Science.gov

Sample records for inzet van biomassa

  1. 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.

  2. VAN method lacks validity

    NASA Astrophysics Data System (ADS)

    Jackson, David D.; Kagan, Yan Y.

    Varotsos and colleagues (the VAN group) claim to have successfully predicted many earthquakes in Greece. Several authors have refuted these claims, as reported in the May 27,1996, special issue of Geophysical Research Letters and a recent book, A Critical Review of VAN [Lighthill 1996]. Nevertheless, the myth persists. Here we summarize why the VAN group's claims lack validity.The VAN group observes electrical potential differences that they call “seismic electric signals” (SES) weeks before and hundreds of kilometers away from some earthquakes, claiming that SES are somehow premonitory. This would require that increases in stress or decreases in strength cause the electrical variations, or that some regional process first causes the electrical signals and then helps trigger the earthquakes. Here we adopt their notation SES to refer to the electrical variations, without accepting any link to the quakes.

  3. Van Gogh Sun

    NASA Video Gallery

    Nicholeen Viall, a solar scientist at NASA's Goddard Space Flight Center creates images of the sun reminiscent of Van Gogh, but it's science, not art. The color of each pixel contains a wealth of i...

  4. Remembering Van Gogh.

    ERIC Educational Resources Information Center

    Freifeld, Susan

    1999-01-01

    Describes an activity in which fourth grade students created a three-dimensional representation of Vincent Van Gogh's room in Arles (France). Expounds that the students had to invent their own strategies for three-dimensional construction and two-dimensional embellishment. Provides directions for creating the room and bed. (CMK)

  5. Segments of van Gogh.

    ERIC Educational Resources Information Center

    Mannlein, Sally

    2002-01-01

    Describes an art project that was used with first grade students in which they learn about Vincent van Gogh's style of painting. Explains that the children learn to create circles and straight lines and how to fill in with color. (CMK)

  6. 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…

  7. Van Gogh's Sunflowers

    ERIC Educational Resources Information Center

    Daddino, Michelle

    2010-01-01

    In this article, the author describes an art project wherein kindergarten students painted sunflowers. These beautiful and colorful sunflowers were inspired by the book "Camille and the Sunflowers" by Laurence Anholt, which does an amazing job of introducing young children to the art and life of Vincent van Gogh.

  8. Van der Waals Forces

    NASA Astrophysics Data System (ADS)

    Parsegian, V. Adrian

    2006-03-01

    This should prove to be the definitive work explaining van der Waals forces, how to calculate them and take account of their impact under any circumstances and conditions. These weak intermolecular forces are of truly pervasive impact, and biologists, chemists, physicists and engineers will profit greatly from the thorough grounding in these fundamental forces that this book offers. Parsegian has organized his book at three successive levels of mathematical sophistication, to satisfy the needs and interests of readers at all levels of preparation. The Prelude and Level 1 are intended to give everyone an overview in words and pictures of the modern theory of van der Waals forces. Level 2 gives the formulae and a wide range of algorithms to let readers compute the van der Waals forces under virtually any physical or physiological conditions. Level 3 offers a rigorous basic formulation of the theory. Author is among the most highly respected biophysicists Van der Waals forces are significant for a wide range of questions and problems in the life sciences, chemistry, physics, and engineering, ranging up to the macro level No other book that develops the subject vigorously, and this book also makes the subject intuitively accessible to students who had not previously been mathematically sophisticated enough to calculate them

  9. Ellis van Creveld syndome.

    PubMed

    Ghanekar, Jaishree; Sangrampurkar, Sujata; Hulinaykar, Raman; Ahmer, Tariq

    2009-07-01

    Ellis-van Creveld syndrome (EVC) or chondroectodermal dysplasia is a rare autosomal recessive disorder. It is a tetrad of chondrodysplasia, ectodermal dysplasia, polydactyly, and congenital heart disease. In several case reports, dysplasia involving other organs has also been identified. The exact prevalence is unknown, but the syndrome seems more common among the Amish community. Many Indian cases have also been reported. This report describes a classical case of EVC syndrome in a 22 year old woman of Indian origin born of a consanginous marriage. The patient had chondrodysplasia of tubular bones resulting in disproportionate dwarfism, postaxial polydactyly, severely dystrophic nails, partially absent teeth, pectus excavatum with narrow chest, knock knees and AV canal defect. PMID:20329417

  10. [Theo van Gogh's medical record].

    PubMed

    Voskuil, P H

    1992-09-01

    In the final months of his life Theo van Gogh was admitted to the 'Geneeskundig Gesticht voor Krankzinnigen te Utrecht'. In November 1990 from the archives of the Willem Arntsz Huis, psychiatric centre in Utrecht, the medical files from this period were made available and a transcription was made by Han van Crimpen and Sjraar van Heugten, scientific collaborators of the Van Gogh Museum. From these data it is acceptable to conclude that Theo van Gogh had dementia paralytica and suffered a fast deterioration of his situation in these last few months. It is, however, probable that at least as early as 1886 Theo showed the first symptoms of this disease when he was in Paris, and that he was treated for this reason by dr. Rivet and dr. Gruby. There are insufficient indications that in Vincent van Gogh's case the same diagnosis can be put forward. It is most probable that during Vincent's visit to Theo in Paris in July 1890 in Theo's case symptoms of his medical deterioration were to be seen and this may have influenced the considerations finally leading to Vincent van Gogh's suicide.

  11. [Van-der-Woude Syndrome].

    PubMed

    Del Frari, B; Amort, M; Janecke, A R; Schutte, B C; Piza-Katzer, H

    2008-01-01

    We report on two families with different expression of a Van-der-Woude-Syndrome (VWS) and with proven mutation of the IRF6- gene. The Van-der-Woude syndrome is a rare disease, typically consisting of congenital pits of the lower lip in combination with cleft lip or cleft palate or both. The Van-der-Woude syndrome is an autosomal dominant syndrome with variable expression. The penetrance is between 0,89 and 0,99. It is important to establish the correct diagnosis by careful investigation of patients with cleft lip or cleft palate and their parents. Genetic counselling is recommended in such cases. PMID:18095255

  12. Ellis-van Creveld syndrome

    MedlinePlus

    Chondroectodermal dysplasia; EVC ... 1 of 2 Ellis-van Creveld syndrome genes ( EVC and EVC2 ). These genes are positioned next to ... performed for mutations in 1 of the 2 EVC genes Skeletal x-ray Ultrasound Urinalysis

  13. 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.

  14. SLAM in a van

    NASA Astrophysics Data System (ADS)

    Binns, Lewis A.; Valachis, Dimitris; Anderson, Sean; Gough, David W.; Nicholson, David; Greenway, Phil

    2002-07-01

    We have developed techniques for Simultaneous Localization and Map Building based on the augmented state Kalman filter, and demonstrated this in real time using laboratory robots. Here we report the results of experiments conducted out doors in an unstructured, unknown, representative environment, using a van equipped with a laser range finder for sensing the external environment, and GPS to provide an estimate of ground truth. The goal is simultaneously to build a map of an unknown environment and to use that map to navigate a vehicle that otherwise would have no way of knowing its location. In this paper we describe the system architecture, the nature of the experimental set up, and the results obtained. These are compared with the estimated ground truth. We show that SLAM is both feasible and useful in real environments. In particular, we explore its repeatability and accuracy, and discuss some practical implementation issues. Finally, we look at the way forward for a real implementation on ground and air vehicles operating in very demanding, harsh environments.

  15. Twisted Van der Waals Systems

    NASA Astrophysics Data System (ADS)

    Gani, Satrio; Rossi, Enrico

    Van der Waals systems formed by two-dimensional (2D) crystals and nanostructures possess electronic properties that make them extremely interesting for basic science and for possible technological applications. By tuning the relative angle (the twist angle) between the layers, or nanostructures, forming the Van der Waals systems experimentalists have been able to control the stacking configuration of such systems. We study the dependence on the twist angle of the electronic properties of two classes of Van der Waals systems: double layers formed by two, one-atom thick, layers of a metal dichalcogenide such as molybdenum disulfide (MoS2), and graphene nanoribbons on a hexagonal boron nitride substrate. We present results that show how, for both classes of systems, the electronic properties can be strongly tuned via the twist angle. Work supported by ACS-PRF-53581-DNI5 and NSF-DMR-1455233.

  16. 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)

  17. Van Gogh's vision. Digitalis intoxication?

    PubMed

    Lee, T C

    1981-02-20

    Vincent van Gogh, the Dutch postimpressionist painter, died in 1890. He was an uncommon man. Automutilation, depression, insanity, and suicide are part of his medical history. During the last few years of his life, his paintings were characterized by halos and the color yellow. Critics have ascribed these aberrations to innumerable causes, including chronic solar injury, glaucoma, and cataracts. Van Gogh may have been under the influence of digitalis intoxication and its side effects: xanthopsia and coronas. This hypothesis is based on his twice having painted his physician holding a foxglove plant; that this medicine was used in the latter part of the 19th century in the treatment of epilepsy; and that the toxic effects of digitalis may have, in part, dictated the artist's technique.

  18. 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..., aircraft, rail cars, trucks, other vehicles, trailers, pallets, cargo vans, lift vans, or similar...

  19. [The psychiatric disease of Vincent van Gogh].

    PubMed

    Lemke, S; Lemke, C

    1993-09-01

    From more than 650 letters of van Gogh psychopathologically striking phrases were collected. Their occurrence in the last 18 years of van Gogh's life was observed. The very different interpretations of his symptoms were compiled in a schedule. Finally the case of van Gogh's is used to discuss the borderline between psychosis and epilepsy, a topic which has long been neglected in German psychiatric teaching.

  20. Indoor Radon Measurement in Van

    NASA Astrophysics Data System (ADS)

    Kam, E.; Osmanlioglu, A. E.; Dogan, I.; Celebi, N.

    2007-04-01

    In this study, indoor radon concentrations obtained from the radon surveys conducted in the Van. Radon monitoring was performed by applying a passive, time-integrating measuring technique. For this purpose, CR-39 nuclear track detectors were installed in dwellings for 2 months. After the monitoring period, detectors were collected. In order to make the alpha tracks visible, chemical etching was applied to the exposed detectors. Nuclear track numbers and the corresponding indoor radon concentrations were determined. Annual effective dose equivalents and the risk probabilities caused by indoor radon inhalation were calculated, and the found results compared with the indoor radon concentrations' data measured in different provinces of Turkey.

  1. Indoor Radon Measurement in Van

    SciTech Connect

    Kam, E.; Osmanlioglu, A. E.; Celebi, N.; Dogan, I.

    2007-04-23

    In this study, indoor radon concentrations obtained from the radon surveys conducted in the Van. Radon monitoring was performed by applying a passive, time-integrating measuring technique. For this purpose, CR-39 nuclear track detectors were installed in dwellings for 2 months. After the monitoring period, detectors were collected. In order to make the alpha tracks visible, chemical etching was applied to the exposed detectors. Nuclear track numbers and the corresponding indoor radon concentrations were determined. Annual effective dose equivalents and the risk probabilities caused by indoor radon inhalation were calculated, and the found results compared with the indoor radon concentrations' data measured in different provinces of Turkey.

  2. Vincent van Gogh: The Postman Roulin.

    ERIC Educational Resources Information Center

    Miller, Stacy

    1989-01-01

    Provides a lesson plan for teaching K-three students to analyze and empathize with a portrait by post-impressionist painter Vincent van Gogh. Describes background of the artist and the painting "The Postman Roulin." Suggests instructional strategies, activities, and evaluation methods. Lists bibliographical material relative to van Gogh's life.…

  3. 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 than three students…

  4. Detection of both vanA & vanB genes in vanA phenotypes of Enterococci by Taq Man RT-PCR

    PubMed Central

    Mirzaei, Bahman; Babaei, Ryhane; Asiabar, Akbar Pour Dadash; Bameri, Zakaria

    2015-01-01

    Twenty seven isolates of vancomycin resistant Enterococci based on the disk diffusion and E- test have been screened; being found eight (0.3%) clinical isolates of vanA & vanB through Taq Man Real Time PCR assay. This study shows the presence of both vanA & vanB genotypes in vanA phenotypes clinical isolates in the three hospitals in Iran. PMID:26221103

  5. Ellis-van Creveld syndrome

    PubMed Central

    Sasalawad, Shilpa S; Hugar, Shivayogi M; Poonacha, K S; Mallikarjuna, Rachappa

    2013-01-01

    Ellis-van Creveld (EvC) syndrome or chondroectodermal dysplasia is an autosomal recessive disorder with characteristic clinical manifestations. The four principal characteristics are chondrodysplasia, polydactyly, ectodermal dysplasia and congenital heart defects. Its incidence in the general population is low. The oral manifestations of EvC syndrome include both soft tissues and teeth, but the dental literature on the subject is scarce. The present case describes the constant and variable oral findings in these patients, which can be diagnosed at any age, even during pregnancy. The presence of a variety of oral manifestations, such as fusion of upper lip to the gingival margin, presence of multiple frenula, abnormally shaped and microdontic teeth and congenitally missing teeth requires multidisciplinary dental treatment, with consideration for the high incidence of cardiac defects in these patients. PMID:23843404

  6. Nonsingular van der Waals potentials

    NASA Astrophysics Data System (ADS)

    Lu, J. X.; Marlow, W. H.

    1995-09-01

    Universal, spherical, nonsingular van der Waals interactions including retardation effect are developed for atoms and small molecules through a semiclassical field approach. Consideration of the finite molecular size effect removes the short-distance singular behavior inherent in the widely used potentials obtained from the point-molecule approximation. Physical arguments lead to the molecular size parameter a (in atomic units) as 1/a=1.25(I/IH)1/2, except for a system that involves at least an atom or a molecule with very different first and second ionization potentials, and for such a system the above numerical factor 1.25 is replaced by unity. Here I and IH are the first ionization potentials for the atom or molecule considered and for a hydrogen atom, respectively. The nonsingular potentials have been tested for the following representative systems: H2 (3Σ+u), He2, Ar2, NaK (3Σ+), LiHg (2Σ+), He-HF, Ne-HF, HF-HF, and Ar-HCl. Very good agreement has been found for each of the systems. Based on the above systems studied, an empirical relation has been obtained between the parameter b in the Born-Mayer repulsive potential Ae-bR and the molecular size parameters (a1 and a2). Applying this relation to dozens of systems with known b from either self-consistent-field calculations or experiments, surprisingly good agreements have been obtained. By the same token, another empirical formula is obtained that relates the van der Waals minimum well parameter Rm to the molecular size parameters (a1 and a2) and the first ionization potentials (Ix and Iy) of interacting species. Again, very good agreements have been achieved in comparison with dozens of systems with known experimental Rm's.

  7. Genetics Home Reference: van der Woude syndrome

    MedlinePlus

    ... people with this disorder are born with a cleft lip , a cleft palate (an opening in the roof ... People with van der Woude syndrome who have cleft lip and/or palate, like other individuals with these ...

  8. 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 --> ∞.

  9. Van Allen Discovery Most Important

    NASA Technical Reports Server (NTRS)

    Jastrow, R.

    1959-01-01

    The first step toward the exploration of space occurred approximately 22 months ago as a part of the International Geophysical Year. In the short interval since October, 1957, the new tools of research, the satellite and the space rocket, have produced two unexpected results of fundamental scientific importance. First, instruments placed in the Explorer satellites by James A. Van Allen have revealed the existence of layers of energetic particles in the outer atmosphere. This discovery constitutes the most significant research achievement of the IGY satellite program. The layers may provide the explanation for the aurora and other geophysical phenomena, and they will also influence the design of vehicles for manned space flight, whose occupants must be shielded against their harmful biological effects. Second, the shape of the earth has been determined very accurately with the aid of data from the first Vanguard. As a result of this investigation, we have found that our planet tends toward the shape of a pear, with its stem at the North Pole. This discovery may produce major changes in our ideas on the interior structure of the earth.

  10. Competition between VanUG Repressor and VanRG Activator Leads to Rheostatic Control of vanG Vancomycin Resistance Operon Expression

    PubMed Central

    Depardieu, Florence; Mejean, Vincent; Courvalin, Patrice

    2015-01-01

    Enterococcus faecalis BM4518 is resistant to vancomycin by synthesis of peptidoglycan precursors ending in D-alanyl-D-serine. In the chromosomal vanG locus, transcription of the resistance genes from the PYG resistance promoter is inducible and, upstream from these genes, there is an unusual three-component regulatory system encoded by the vanURSG operon from the PUG regulatory promoter. In contrast to the other van operons in enterococci, the vanG operon possesses the additional vanUG gene which encodes a transcriptional regulator whose role remains unknown. We show by DNase I footprinting, RT-qPCR, and reporter proteins activities that VanUG, but not VanRG, binds to PUG and negatively autoregulates the vanURSG operon and that it also represses PYG where it overlaps with VanRG for binding. In clinical isolate BM4518, the transcription level of the resistance genes was dependent on vancomycin concentration whereas, in a ΔvanUG mutant, resistance was expressed at a maximum level even at low concentrations of the inducer. The binding competition between VanUG and VanRG on the PYG resistance promoter allowed rheostatic activation of the resistance operon depending likely on the level of VanRG phosphorylation by the VanSG sensor. In addition, there was cross-talk between VanSG and VanR'G, a VanRG homolog, encoded elsewhere in the chromosome indicating a sophisticated and subtle regulation of vancomycin resistance expression by a complex two-component system. PMID:25898178

  11. Ellis-van Creveld syndrome.

    PubMed

    Baujat, Geneviève; Le Merrer, Martine

    2007-06-04

    Ellis-van Creveld syndrome (EVC) is a chondral and ectodermal dysplasia characterized by short ribs, polydactyly, growth retardation, and ectodermal and heart defects. It is a rare disease with approximately 150 cases reported worldwide. The exact prevalence is unknown, but the syndrome seems more common among the Amish community. Prenatal abnormalities (that may be detected by ultrasound examination) include narrow thorax, shortening of long bones, hexadactyly and cardiac defects. After birth, cardinal features are short stature, short ribs, polydactyly, and dysplastic fingernails and teeth. Heart defects, especially abnormalities of atrial septation, occur in about 60% of cases. Cognitive and motor development is normal. This rare condition is inherited as an autosomal recessive trait with variable expression. Mutations of the EVC1 and EVC2 genes, located in a head to head configuration on chromosome 4p16, have been identified as causative. EVC belongs to the short rib-polydactyly group (SRP) and these SRPs, especially type III (Verma-Naumoff syndrome), are discussed in the prenatal differential diagnosis. Postnatally, the essential differential diagnoses include Jeune dystrophy, McKusick-Kaufman syndrome and Weyers syndrome. The management of EVC is multidisciplinary. Management during the neonatal period is mostly symptomatic, involving treatment of the respiratory distress due to narrow chest and heart failure. Orthopedic follow-up is required to manage the bones deformities. Professional dental care should be considered for management of the oral manifestations. Prognosis is linked to the respiratory difficulties in the first months of life due to thoracic narrowness and possible heart defects. Prognosis of the final body height is difficult to predict.

  12. Implementation of Linus Programme Based on the Model of Van Meter and Van Horn

    ERIC Educational Resources Information Center

    Sani, Nazariyah bt; Idris, Abdul Rahman

    2013-01-01

    The purpose of this study is to identify the understanding of school leaders on the implementation of LINUS programme that based on the features contained in the Implementation Model of Van Meter and Van Horn (1975). The study was carried out in the form of qualitative method and particularly, the multiple case studies that were conducted in four…

  13. The illness of Vincent van Gogh.

    PubMed

    Blumer, Dietrich

    2002-04-01

    Vincent van Gogh (1853-1890) had an eccentric personality and unstable moods, suffered from recurrent psychotic episodes during the last 2 years of his extraordinary life, and committed suicide at the age of 37. Despite limited evidence, well over 150 physicians have ventured a perplexing variety of diagnoses of his illness. Henri Gastaut, in a study of the artist's life and medical history published in 1956, identified van Gogh's major illness during the last 2 years of his life as temporal lobe epilepsy precipitated by the use of absinthe in the presence of an early limbic lesion. In essence, Gastaut confirmed the diagnosis originally made by the French physicians who had treated van Gogh. However, van Gogh had earlier suffered two distinct episodes of reactive depression, and there are clearly bipolar aspects to his history. Both episodes of depression were followed by sustained periods of increasingly high energy and enthusiasm, first as an evangelist and then as an artist. The highlights of van Gogh's life and letters are reviewed and discussed in an effort toward better understanding of the complexity of his illness.

  14. Integrable extended van der Waals model

    NASA Astrophysics Data System (ADS)

    Giglio, Francesco; Landolfi, Giulio; Moro, Antonio

    2016-10-01

    Inspired by the recent developments in the study of the thermodynamics of van der Waals fluids via the theory of nonlinear conservation laws and the description of phase transitions in terms of classical (dissipative) shock waves, we propose a novel approach to the construction of multi-parameter generalisations of the van der Waals model. The theory of integrable nonlinear conservation laws still represents the inspiring framework. Starting from a macroscopic approach, a four parameter family of integrable extended van der Waals models is indeed constructed in such a way that the equation of state is a solution to an integrable nonlinear conservation law linearisable by a Cole-Hopf transformation. This family is further specified by the request that, in regime of high temperature, far from the critical region, the extended model reproduces asymptotically the standard van der Waals equation of state. We provide a detailed comparison of our extended model with two notable empirical models such as Peng-Robinson and Soave's modification of the Redlich-Kwong equations of state. We show that our extended van der Waals equation of state is compatible with both empirical models for a suitable choice of the free parameters and can be viewed as a master interpolating equation. The present approach also suggests that further generalisations can be obtained by including the class of dispersive and viscous-dispersive nonlinear conservation laws and could lead to a new type of thermodynamic phase transitions associated to nonclassical and dispersive shock waves.

  15. The illness of Vincent van Gogh.

    PubMed

    Arnold, Wilfred Niels

    2004-03-01

    Vincent van Gogh (1853-1890) was a wonderfully accomplished artist whose work is now widely appreciated. He created a great number of masterpiece paintings and drawings in just one decade devoted to art. His productivity is even more remarkable when considered in the context of his debilitating illness. He suffered from medical crises that were devastating, but in the intervening periods he was both lucid and creative. He left a profound, soul-searching description of his jagged life in his correspondence, which provides the basis for the present analysis. An inherited metabolic disease, acute intermittent porphyria, accounts for all of the signs and symptoms of van Gogh's underlying illness. On this 150th anniversary of the birth of Vincent van Gogh it is appropriate to revisit the subject and to analyze the lack of organized skepticism in the popular media about other diagnoses.

  16. Ellis-van Creveld syndrome: its history.

    PubMed

    Muensterer, Oliver J; Berdon, Walter; McManus, Chris; Oestreich, Alan; Lachman, Ralph S; Cohen, M Michael; Done, Stephen

    2013-08-01

    The story of Ellis-van Creveld syndrome is one of serendipity. By chance, Simon van Creveld and Richard Ellis purportedly met on a train and combined their independently encountered patients with short stature, dental anomalies and polydactyly into one landmark publication in 1940. They included a patient used in work published previously by Rustin McIntosh without naming McIntosh as a coauthor. This patient was followed radiologically by Caffey for nearly two decades. In 1964, Victor McKusick felt compelled to investigate a brief report in an obscure pharmaceutical journal on an unusual geographic cluster of short-statured Amish patients in Pennsylvania. This review highlights the lives of the individuals involved in the discovery of Ellis-van Creveld syndrome in their historic context. PMID:23754541

  17. 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 lift. In the…

  18. Painting with Clay Van Gogh Style.

    ERIC Educational Resources Information Center

    Skophammer, Karen

    1999-01-01

    Discusses Vincent Van Gogh's painting "Starry Night" and describes a lesson where fifth- and sixth-grade students created their own version of the artwork. Explains that the students utilized four colors of Permoplast clay, using their hands and fingers as brushes and blending tools and the clay as paint. (CMK)

  19. Ben van der Veken Honor Issue

    NASA Astrophysics Data System (ADS)

    Durig, James

    2015-02-01

    In acclamation of Ben van der Veken, a former editor of Spectrochimica Acta, many co-authors and friends have submitted papers in his honor. He has collaborated with many scientists from the United States, Russia, England, Scotland as well as some in other countries. His research is known throughout the world.

  20. 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 early…

  1. 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…

  2. 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)

  3. 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…

  4. 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…

  5. 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…

  6. 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…

  7. 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…

  8. 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…

  9. Note on a van der Waals Gas.

    ERIC Educational Resources Information Center

    Bauman, Robert P.; Harrison, Joseph G.

    1996-01-01

    Discusses the difficulties with the standard model for introduction of attractive forces into the van der Waals equation. Presents an analysis in terms of force and time delays and an alternative analysis for more advanced students in terms of energy. (JRH)

  10. 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,…

  11. 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,…

  12. Obituary for Jan van der Pers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    After a short but valiant struggle against cancer, Jan van der Pers died on 29 April, 2006 in the hospital in Hilversum, The Netherlands, close to his home. Our conversations with Jan during the last months of his life showed the remarkable strength and positive attitude typical of him. Discussions...

  13. Cosmic string in the van Stockum cylinder

    NASA Astrophysics Data System (ADS)

    Krisch, J. P.

    2003-05-01

    The low density van Stockum dust solution is extended by including an angular deficit factor. The resulting model describes a rotating Gott-Hiscock string surrounded by an annular dust atmosphere. The interior spacetime can be joined to a vacuum Levi-Civita solution with angular deficit.

  14. Absence of VanA- and VanB-containing enterococci in poultry raised on nonintensive production farms in Brazil.

    PubMed

    Batista Xavier, Diego; Moreno Bernal, Francisco Ernesto; Titze-de-Almeida, Ricardo

    2006-04-01

    We examined cloacal samples from poultry raised on nonintensive production farms in Brazil for the presence of vancomycin-resistant enterococci. No VanA- or VanB-containing enterococci were identified in a total of 200 cloacal swabs. The most prevalent species were Enterococcus gallinarum (vanC1; 13.0%) and E. casseliflavus (vanC2/3; 5.5%).

  15. Van Gogh and the life chart.

    PubMed

    Rahe, R H

    1992-01-01

    Adolf Meyer originally devised the life chart in order to chronologically document a person's major life events and significant illness experiences over his or her life span. It is the purpose of this report to update Meyer's life chart through the presentation of the life events and illnesses of the famous artist Vincent Van Gogh. Van Gogh's life illustrates significant early (predisposing) life stresses, as well as clusterings of stressful (precipitating) life events occurring proximal to the occurrence of his several illnesses. Through the use of a life chart an understanding of why an individual becomes ill at a particular time in their life is enlarged. In addition, a systematic basis for formulating prognosis becomes available.

  16. [Psychiatric case history of Vincent van Gogh].

    PubMed

    van Meekeren, E

    2000-12-23

    Much has been written about Vincent van Gogh's pathological condition. Most authors base their various diagnoses on the symptoms he exhibited in the last years of his life. However, Van Gogh during a much longer part of his life displayed symptoms best consistent with a borderline (personality) disorder: impulsivity, variable moods, self-destructive behaviour, fear of abandonment, an unbalanced self-image, authority conflicts and other complicated relationships. The precipitating element disturbing Vincent's psychic balance--delicate in any case due to a positive family history, malnutrition, intoxication and exhaustion and the borderline disorder--may have been his being deserted by his friend Gauguin. He (also) developed an organic psychosyndrome with psychotic and epileptic elements. The stress (due to social isolation, by his being a psychiatric patient, and by poor prospects), the intoxication going on outside the hospitals and especially also the problems relating to his brother Theo caused a downward spiral culminating in suicide.

  17. Vincent van Gogh and the thujone connection.

    PubMed

    Arnold, W N

    1988-11-25

    During his last two years Vincent van Gogh experienced fits with hallucinations that have been attributed to a congenital psychosis. But the artist admitted to episodes of heavy drinking that were amply confirmed by colleagues and there is good evidence to indicate that addiction to absinthe exacerbated his illness. Absinthe was distilled from an alcoholic steep of herbs. Wormwood (Artemisia absinthium) was the most significant constituent because it contributed thujone. This terpene can cause excitation, convulsions that mimic epilepsy, and even permanent brain damage. Statements in van Gogh's letters and from his friends indicate that he had an affinity for substances with a chemical connection to thujone; the documented examples are camphor and pinene. Perhaps he developed an abnormal craving for terpenes, a sort of pica, that would explain his attempts to eat paints and so on, which were previously regarded as unrelated absurdities.

  18. 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, as 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.

  19. [Drugs and poisons in the life of Vincent van Gogh].

    PubMed

    Berggren, L

    1997-01-01

    Van Gogh was during his last years exposed to several potentially toxic substances such as; bromides, lead, camphor and terpene oils in absinthe liquor. All of them produce signs of toxicity which are similar to the symptoms known from van Gogh's attacks of illness; hallucinations, confusion, delirium, convulsions and agitation. However, the many interpretations of van Gogh's illness and state of mind have in most cases not taken into account the possible influence of toxic chemicals.

  20. 78 FR 28947 - Fund Availability Under VA's Homeless Providers Grant and Per Diem Program (VANS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-16

    ... a job description for the van operator that details the following: (a) Requirements of the position... will take for the van(s) acquisition to occur. Description of Need: The information you provide here...) for special disabled individual transportation? Description of Activity: Describe how the van(s)...

  1. Van Kampen modes for bunch longitudinal motion

    SciTech Connect

    Burov, A.; /Fermilab

    2010-09-01

    Conditions for existence, uniqueness and stability of bunch steady states are considered. For the existence uniqueness problem, simple algebraic equations are derived, showing the result both for the action and Hamiltonian domain distributions. For the stability problem, van Kampen theory is used. Emerging of discrete van Kampen modes show either loss of Landau damping, or instability. This method can be applied for an arbitrary impedance, RF shape and beam distribution function Available areas on intensity-emittance plane are shown for resistive wall wake and single harmonic, bunch shortening and bunch lengthening RF configurations. Language of van Kampen modes is a powerful tool for studying beam stability. Its unique efficiency reveals itself in those complicated cases, when the dielectric function cannot be obtained, as it is for the longitudinal bunch motion. Emergence of a discrete mode means either loss of Landau damping or instability. By definition, the discrete modes lie outside the continuous incoherent spectrum, but they still may stay within the bucket. In the last case, the discrete mode would disappear after a tiny portion of resonant particles would be added. However, if the discrete mode lie outside the bucket, the Landau damping cannot be restored by tiny perturbation of the particle distribution; LLD is called radical in that case. For a given bunch emittance and RF voltage, the intensity is limited either by reduction of the bucket acceptance or by (radical) LLD. In this paper, results are presented for longitudinal bunch stability in weak head-tail approximation and resistive wall impedance; three RF configurations are studied: single harmonic, bunch shortening and bunch lengthening. It is shown that every RF configuration may be preferable, depending on the bunch emittance and intensity.

  2. [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".

  3. [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". PMID:23527448

  4. van der Waals Heterostructures Grown by MBE

    NASA Astrophysics Data System (ADS)

    Hinkle, Christopher

    In this work, we demonstrate the high-quality MBE heterostructure growth of various layered 2D materials by van der Waals epitaxy (VDWE). The coupling of different types of van der Waals materials including transition metal dichalcogenide thin films (e.g., WSe2, WTe2, HfSe2) , insulating hexagonal boron nitride (h-BN), and topological insulators (e.g., Bi2Se3) allows for the fabrication of novel electronic devices that take advantage of unique quantum confinement and spin-based characteristics. The relaxed lattice-matching criteria of van der Waals epitaxy has allowed for high-quality heterostructure growth with atomically abrupt interfaces, allowing us to couple these materials based primarily on their band alignment and electronic properties. We will discuss the impact of sample preparation, surface reactivity, and lattice mismatch of various substrates (sapphire, graphene, TMDs, Bi2Se3) on the growth mode and quality of the films and will discuss our studies of substrate temperature and flux rates on the resultant growth and grain size. Structural and chemical characterization was conducted via reflection high energy electron diffraction (RHEED, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning tunneling microscopy/spectroscopy (STM/S), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Experimentally determined band alignments have been determined and compared with first-principles calculations allowing the design of novel low-power logic and magnetic memory devices. Initial results from the electrical characterization of these grown thin films and some simple devices will also be presented. These VDWE grown layered 2D materials show significant potential for fabricating novel heterostructures with tunable band alignments and magnetic properties for a variety of nanoelectronic and optoelectronic applications.

  5. 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. PMID:7012367

  6. 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.

  7. 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…

  8. 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,…

  9. Vincent van Gogh: a pathographic analysis.

    PubMed

    Correa, R

    2014-02-01

    The life and artistic legacy of Vincent van Gogh has generated great interest among physicians from different areas of specialization in proposing a retrospective differential diagnosis. The aim of the present study is to present a systematic pathographic analysis of the artist and to suggest a diagnosis consistent with the extant evidence. To this end, the available evidence is classified into five types: type I evidence (clinical opinion of an attending physician), type II evidence (description of symptoms in correspondence), type III evidence (historical accounts from first-hand sources or direct observation), type IV evidence (interpretation of the artist's work) and type V evidence (family medical history). Three basic prerequisites for a successful analysis are: (1) consideration of type II, III and V evidence as carrying the greatest pathographic weight, (2) consideration of the course of symptoms over time as a key element in the analysis, and (3) consideration of a single diagnostic hypothesis as the most probable explanation. After reviewing the available evidence in the light of these criteria, the author supports the diagnosis of acute intermittent porphyria (AIP) as the most likely cause of van Gogh's ailment.

  10. [The psychiatric illness of Vincent van Gogh].

    PubMed

    Strik, W K

    1997-05-01

    Vincent van Gogh's illness has been the object of much speculation. Explanations as disparate as acute intermittent porphyria, epilepsy and schizophrenia have been proposed. Many of the diagnostic hypotheses, however, are based on partial or incomplete consideration of the biography and of the reports of his subjective experience in his letters to his brother. Karl Leonhard showed, in a detailed analysis of Vincent's biography, that both the course and symptoms of the disorder were consistent with the diagnosis of a cycloid psychosis (anxiety-elation psychosis). In the present paper, the diagnostic judgement of Leonhard is described and discussed in the light of independent research on van Gogh's letters, his works and biography. The bibliographical sources were investigated for information consistent with a cycloid psychosis, but also for information that might contradict this hypothesis. The course and symptoms of the disorder are presented as comprehensively and systematically as possible and are documented with the respective citations. Furthermore, the most important diagnoses proposed in the literature are critically discussed. Based on this investigation, it was possible to show that only the diagnosis of a cycloid psychosis allowed us to connect all the available information to a typical psychiatric syndrome.

  11. Van der Waals heterostructures and devices

    NASA Astrophysics Data System (ADS)

    Liu, Yuan; Weiss, Nathan O.; Duan, Xidong; Cheng, Hung-Chieh; Huang, Yu; Duan, Xiangfeng

    2016-09-01

    Two-dimensional layered materials (2DLMs) have been a central focus of materials research since the discovery of graphene just over a decade ago. Each layer in 2DLMs consists of a covalently bonded, dangling-bond-free lattice and is weakly bound to neighbouring layers by van der Waals interactions. This makes it feasible to isolate, mix and match highly disparate atomic layers to create a wide range of van der Waals heterostructures (vdWHs) without the constraints of lattice matching and processing compatibility. Exploiting the novel properties in these vdWHs with diverse layering of metals, semiconductors or insulators, new designs of electronic devices emerge, including tunnelling transistors, barristors and flexible electronics, as well as optoelectronic devices, including photodetectors, photovoltaics and light-emitting devices with unprecedented characteristics or unique functionalities. We review the recent progress and challenges, and offer our perspective on the exploration of 2DLM-based vdWHs for future application in electronics and optoelectronics.

  12. 53. Photographer unknown Date unknown VAN DUZEN BRIDGE, HUMBOLDT COUNTY, ...

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

    53. Photographer unknown Date unknown VAN DUZEN BRIDGE, HUMBOLDT COUNTY, SECTION F, HIGHWAY 1. 1. 1-HUM-1-F #24, VAN DUZEN BR. APPRAOCH/ST. 167+50. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  13. United Parcel Service Evaluates Hybrid Electric Delivery Vans (Fact Sheet)

    SciTech Connect

    Not Available

    2010-02-01

    This fact sheet describes how the National Renewable Energy Laboratory's Fleet Test and Evaluation team evaluated the 12-month, in-service performance of six Class 4 hybrid electric delivery vans - fueled by regular diesel - and six comparable conventional diesel vans operated by the United Parcel Service.

  14. 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. Based 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 function

  15. Tunnelling in van der Waals heterostructures

    NASA Astrophysics Data System (ADS)

    Mishchenko, Artem; Novoselov, Kostya; Geim, Andre; Eaves, Laurence; Falko, Vladimir

    When graphene and other conductive two-dimensional (2D) materials are separated by an atomically thin insulating 2D crystal, quantum mechanical tunnelling leads to appreciable current between two 2D conductors due to the overlap of their wavefunctions. These tunnel devices demonstrate interesting physics and potential for applications: such effects as resonant tunnelling, negative differential conductance, light emission and detection have already been demonstrated. In this presentation we will outline the current status and perspectives of tunnelling transistors based on 2D materials assembled into van der Waals heterostructures. Particularly, we will present results on mono- and bilayer graphene tunnelling, tunnelling in 2D crystal-based quantum wells, and tunnelling in superconducting 2D materials. Such effects as momentum and chirality conservation, phonon- and impurity-assisted tunnelling will also be discussed. Finally, we will ponder the implications of discovered effects for practical applications.

  16. Ellis-van Creveld syndrome and dyserythropoiesis.

    PubMed

    Scurlock, Deven; Ostler, Daniel; Nguyen, Andy; Wahed, Amer

    2005-05-01

    Ellis-van Creveld (EVC) syndrome or chondroectodermal dysplasia is a rare autosomal recessive disorder characterized by a variable spectrum of clinical findings. Classical EVC syndrome comprises a tetrad of clinical manifestations of chondrodystrophy, polydactyly, ectodermal dysplasia, and cardiac defects. In several case reports, dysplasia involving other organs has also been identified. Hematologic abnormalities have been rarely reported in patients with EVC syndrome. Here, we report a case of a 3-year-old Hispanic boy with EVC syndrome and marked dyserythropoiesis. The dyserythropoiesis may be part of an isolated myelodysplastic change or a primary myelodysplastic syndrome and likely represents an unusual EVC syndrome association. To our knowledge, this association has not been previously reported.

  17. 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.

  18. van Vleck determinants: Traversable wormhole spacetimes

    SciTech Connect

    Visser, M. )

    1994-04-15

    Prompted by various questions regarding the putative existence, stability, and chronological properties of traversable wormholes, a number of authors have presented calculations of the renormalized stress-energy tensor in wormhole spacetimes. In particular, the use of point-splitting techniques leads to expressions that contain the van Vleck determinant as a common prefactor. Recent technical advances permit one to undertake extensive computations of the van Vleck determinant in traversable wormhole spacetimes, at least in the short-throat flat-space approximation. This paper presents several such computations for various model spacetimes. Implications with regard to Hawking's chronology protection conjecture are discussed. In particular, any attempt to transform a single isolated wormhole into a time machine results in large vacuum polarization effects. These vacuum polarization effects are sufficient to disrupt the internal structure of the wormhole long before the onset of Planck scale physics, and before the onset of time travel. Thus for isolated wormholes, vacuum polarization effects are sufficient to enforce Hawking's chronology protection conjecture. On the other hand, it is possible to conceive of a putative time machine built out of two or more wormholes, each of which taken in isolation is not itself a time machine. Such Roman configurations'' are much more subtle to analyze. For reasonable'' configurations (traversable by humans) the vacuum polarization effects in such multiple wormhole putative time machines become large long before the onset of Planck scale physics. The disruption scale for would-be traversable time machines'' is well above the Planck length. On the other hand, for some particularly bizarre configurations (not traversable by humans) the vacuum polarization effects can be arranged to be arbitrarily small at the onset of Planck scale physics.

  19. Resonance Van Hove singularities in wave kinetics

    NASA Astrophysics Data System (ADS)

    Shi, Yi-Kang; Eyink, Gregory L.

    2016-10-01

    Wave kinetic theory has been developed to describe the statistical dynamics of weakly nonlinear, dispersive waves. However, we show that systems which are generally dispersive can have resonant sets of wave modes with identical group velocities, leading to a local breakdown of dispersivity. This shows up as a geometric singularity of the resonant manifold and possibly as an infinite phase measure in the collision integral. Such singularities occur widely for classical wave systems, including acoustical waves, Rossby waves, helical waves in rotating fluids, light waves in nonlinear optics and also in quantum transport, e.g. kinetics of electron-hole excitations (matter waves) in graphene. These singularities are the exact analogue of the critical points found by Van Hove in 1953 for phonon dispersion relations in crystals. The importance of these singularities in wave kinetics depends on the dimension of phase space D =(N - 2) d (d physical space dimension, N the number of waves in resonance) and the degree of degeneracy δ of the critical points. Following Van Hove, we show that non-degenerate singularities lead to finite phase measures for D > 2 but produce divergences when D ≤ 2 and possible breakdown of wave kinetics if the collision integral itself becomes too large (or even infinite). Similar divergences and possible breakdown can occur for degenerate singularities, when D - δ ≤ 2, as we find for several physical examples, including electron-hole kinetics in graphene. When the standard kinetic equation breaks down, then one must develop a new singular wave kinetics. We discuss approaches from pioneering 1971 work of Newell & Aucoin on multi-scale perturbation theory for acoustic waves and field-theoretic methods based on exact Schwinger-Dyson integral equations for the wave dynamics.

  20. The extraordinary career of Professor Dr. Simon van Creveld.

    PubMed

    Stoelinga, Paul J W; Berdon, Walter E; Cohen, M Michael

    2014-11-01

    Simon van Creveld received both the MD and PhD degrees and had a multifaceted medical and scientific education at many hospitals and research institutes in the Netherlands, Germany, and the UK. He and his wife were the first to develop insulin for the Netherlands. His major interests were in hemophilia and hemorrhagic disorders, which accounted for 87 of his publications. In 1934, van Creveld demonstrated that a dispersed protein fraction obtained from serum could reduce the clotting time of hemophilic blood. His interest in glycogen storage disease resulted in van Creveld-von Gierke disease for which van Creveld contributed four published articles. The Ellis-van Creveld syndrome, also known as chondroectodermal dysplasia, was published in 1940 and became well known to medical geneticists. During the Nazi occupation of the Netherlands, van Creveld's professorship was taken away from him because he was Jewish. His visits to hospitals of concentration camps to treat babies and give pediatric advice while wearing a Jewish Yellow Star and interacting with SS Commandants in charge, and then leaving can only be described as amazing. After the war, his professorship was returned, and in the same year as his retirement, he established a large Hemophila Treatment and Research Center now known as the Van Creveld Clinic, which celebrated its 40th anniversary in 2005. PMID:25269937

  1. [The simultaneous contrast of the colors in Van Gogh paints].

    PubMed

    Cernea, P

    2002-01-01

    Vincent Van Gogh, Dutchman painter, is a forerunner but also a spokesman of the expressionism. His life was short and sad, marked by a psychic instability. In his paintings the color is subordinated of some subjective motivations. Van Gogh uses complementary colors to get a maximum intensity of the overlapped tones. The chromatic increase serves to obtain some strong emotions. In his landscapes the special distances are suggested through tonal distances. The increase of the pure tones through complementary contrast, the cancel of the imitation colors through sensation-colors, the explosive chromatic are characteristic of her painting. In his singular creation, Vincent Van Gogh created his suffering ego.

  2. The artist in the hospital: the van Gogh case.

    PubMed

    Meissner, W W

    1994-01-01

    As a result of psychotic crises, Vincent van Gogh was hospitalized several times during a period of about a year and a half from December 1888 to May 1890. The author focuses on van Gogh's intense intrapsychic struggle during this relatively brief but critical time. He discusses how van Gogh's painting not only reflected his struggles but also enabled him, for a time, to stave off the hopelessness and despair that eventually overwhelmed him, culminating in his suicide. After reviewing possible factors in the artist's illness, the author agrees with others that the most persuasive explanation involves epileptic underpinnings.

  3. 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.

  4. Characterization of an Enterococcus gallinarum Isolate Carrying a Dual vanA and vanB Cassette.

    PubMed

    Eshaghi, Alireza; Shahinas, Dea; Li, Aimin; Kariyawasam, Ruwandi; Banh, Philip; Desjardins, Marc; Melano, Roberto G; Patel, Samir N

    2015-07-01

    The ability of vancomycin resistance determinants to be horizontally transferred within enterococci species is a concern. Identification and characterization of vancomycin-resistant enterococci (VRE) in a clinical isolate have a significant impact on infection control practices. In this study, we describe a clinical isolate of Enterococcus gallinarum exhibiting high-level resistance to vancomycin and teicoplanin. The genetic characterization of this isolate showed the presence of vanA and vanB genes in addition to the naturally carried vanC gene. vanA was identified on pA6981, a 35,608-bp circular plasmid with significant homology to plasmid pS177. The vanB operon was integrated into the bacterial chromosome and showed a high level of homology to previously reported Tn1549 and Tn5382. To the best of our knowledge, this is the first report of E. gallinarum carrying both vanA and vanB operons, indicating the importance of identifying the vancomycin resistance mechanism in non-E. faecium and non-E. faecalis enterococcal species.

  5. Van Gogh's disease in the light of his correspondence.

    PubMed

    Voskuil, Piet H A

    2013-01-01

    The literary quality of Vincent van Gogh's correspondence is widely recognized. He wrote expressively and evocatively, and had great literary knowledge. In this essay we follow his medical history in many quotes from in his letters to see how Vincent expressed his complaints, knowledge, and emotions connected with his disease. The symptoms became most clear after December 1888. In the beginning, Van Gogh hesitated to tell much about his ailment, but gradually painted in the letters his experiences, making use of the intermittent course of his cycloid psychoses. We will see an indication that, in the network that mediated Van Gogh's brain (dys)function, elements of synesthesia, prosopagnosia, and spatial agnosia might have been activated. Van Gogh's affinity for poetry, already in his early twenty's, makes the hypothesis of a, by epileptic discharges, kindled temporal lobe at most only part of the complex interpretation of this creative and suffering mind.

  6. 46 CFR 194.10-15 - Magazine van construction.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... construction. (a) Vans shall be of substantial metal construction. Their interior shall be insulated with an... label plate stating light weight, gross weight and weight of explosives. Gross weight shall not...

  7. 46 CFR 194.10-15 - Magazine van construction.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... construction. (a) Vans shall be of substantial metal construction. Their interior shall be insulated with an... label plate stating light weight, gross weight and weight of explosives. Gross weight shall not...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... construction. (a) Vans shall be of substantial metal construction. Their interior shall be insulated with an... label plate stating light weight, gross weight and weight of explosives. Gross weight shall not...

  9. 21. View West, Detail Mural, Children's Room, Rip Van Winkle ...

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

    21. View West, Detail Mural, Children's Room, Rip Van Winkle Mural, Project of the CWA (Civil Works Administration) Completed May 1934. - Ives Memorial Library, 133 Elm Street, New Haven, New Haven County, CT

  10. 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.

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

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

    1. Historic American Buildings Survey Cortlandt Van Dyke Hubbard, Photographer June 1960 EXTERIOR OF THE SOUTH AND EAST ELEVATIONS - The Judges Law Office, 100 West Market Street, Georgetown, Sussex County, DE

  12. Genetics Home Reference: Ellis-van Creveld syndrome

    MedlinePlus

    ... bone growth that results in very short stature (dwarfism). People with this condition have particularly short forearms ... Ellis-van Creveld Syndrome Encyclopedia: Polydactyly Health Topic: Dwarfism Genetic and Rare Diseases Information Center (1 link) ...

  13. 76 FR 13192 - Mark E. Van Wormer: Debarment Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-10

    ... the Federal Food, Drug, and Cosmetic Act (the FD&C Act) permanently debarring Mark E. Van Wormer, MD... Imaging and Laser Surgery Center, PC, and the Physicians GreatSkin Clinic. From on or about January...

  14. 1. Photocopy from stereoptican picture (original owned by Charles van ...

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

    1. Photocopy from stereoptican picture (original owned by Charles van Ravenswaay, Wilmington, Delaware) J. C. Macurdy, Photographer ca. 1871 EXTERIOR IN 1871 - St. Peter & Paul Roman Catholic Church, Seventh & Spring Streets, Boonville, Cooper County, MO

  15. 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.

  16. "Public" and "Private" Meanings: The Paintings of van Gogh.

    ERIC Educational Resources Information Center

    Roskill, Mark

    1979-01-01

    Examines the distinctions and interrelation of the artist's intentions and the viewers' understanding of a work of art by using the work of Vincent van Gogh and relating it to the artist's correspondence about his own work. (JMF)

  17. The neuropsychiatric ailment of Vincent Van Gogh.

    PubMed

    Bhattacharyya, Kalyan B; Rai, Saurabh

    2015-01-01

    Vincent Van Gogh is one of the most celebrated creative artists of all time. All his life, he was afflicted by some kind of neurological or psychiatric disorder, which remains a mystery even today. Many historians and his personal physicians believe that he suffered from epilepsy while others felt that he was affected by Ménière's disease. Features such as hypergraphia, atypical sexuality, and viscosity of thinking suggest the possibility of Gastaut-Geschwind phenomenon, a known complication of complex partial seizure. On the contrary, some historians feel that he was forced to sever his right ear in order to get relief from troublesome tinnitus, a complication of Ménière's disease. He was addicted to the liquor absinthe, which is known to lead to xanthopsia, and many authorities argue that this was the reason for his penchant for the deep and bright yellow color in many of his paintings. Others have suggested the possibility of bipolar disorder, sunstroke, acute intermittent porphyria, and digitalis toxicity as well.

  18. Ripplocations in van der Waals layers.

    PubMed

    Kushima, Akihiro; Qian, Xiaofeng; Zhao, Peng; Zhang, Sulin; Li, Ju

    2015-02-11

    Dislocations are topological line defects in three-dimensional crystals. Same-sign dislocations repel according to Frank's rule |b1 + b2|(2) > |b1|(2) + |b2|(2). This rule is broken for dislocations in van der Waals (vdW) layers, which possess crystallographic Burgers vector as ordinary dislocations but feature "surface ripples" due to the ease of bending and weak vdW adhesion of the atomic layers. We term these line defects "ripplocations" in accordance to their dual "surface ripple" and "crystallographic dislocation" characters. Unlike conventional ripples on noncrystalline (vacuum, amorphous, or fluid) substrates, ripplocations tend to be very straight, narrow, and crystallographically oriented. The self-energy of surface ripplocations scales sublinearly with |b|, indicating that same-sign ripplocations attract and tend to merge, opposite to conventional dislocations. Using in situ transmission electron microscopy, we directly observed ripplocation generation and motion when few-layer MoS2 films were lithiated or mechanically processed. Being a new subclass of elementary defects, ripplocations are expected to be important in the processing and defect engineering of vdW layers.

  19. Supercurrent in van der Waals Josephson junction.

    PubMed

    Yabuki, Naoto; Moriya, Rai; Arai, Miho; Sata, Yohta; Morikawa, Sei; Masubuchi, Satoru; Machida, Tomoki

    2016-01-01

    Supercurrent flow between two superconductors with different order parameters, a phenomenon known as the Josephson effect, can be achieved by inserting a non-superconducting material between two superconductors to decouple their wavefunctions. These Josephson junctions have been employed in fields ranging from digital to quantum electronics, yet their functionality is limited by the interface quality and use of non-superconducting material. Here we show that by exfoliating a layered dichalcogenide (NbSe2) superconductor, the van der Waals (vdW) contact between the cleaved surfaces can instead be used to construct a Josephson junction. This is made possible by recent advances in vdW heterostructure technology, with an atomically flat vdW interface free of oxidation and inter-diffusion achieved by eliminating all heat treatment during junction preparation. Here we demonstrate that this artificially created vdW interface provides sufficient decoupling of the wavefunctions of the two NbSe2 crystals, with the vdW Josephson junction exhibiting a high supercurrent transparency.

  20. [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.

  1. Dielectric Genome of van der Waals Heterostructures.

    PubMed

    Andersen, Kirsten; Latini, Simone; Thygesen, Kristian S

    2015-07-01

    Vertical stacking of two-dimensional (2D) crystals, such as graphene and hexagonal boron nitride, has recently lead to a new class of materials known as van der Waals heterostructures (vdWHs) with unique and highly tunable electronic properties. Ab initio calculations should in principle provide a powerful tool for modeling and guiding the design of vdWHs, but in their traditional form such calculations are only feasible for commensurable structures with a few layers. Here we show that the dielectric properties of realistic, incommensurable vdWHs comprising hundreds of layers can be efficiently calculated using a multiscale approach where the dielectric functions of the individual layers (the dielectric building blocks) are computed ab initio and coupled together via the long-range Coulomb interaction. We use the method to illustrate the 2D-3D transition of the dielectric function of multilayer MoS2 crystals, the hybridization of quantum plasmons in thick graphene/hBN heterostructures, and to demonstrate the intricate effect of substrate screening on the non-Rydberg exciton series in supported WS2. The dielectric building blocks for a variety of 2D crystals are available in an open database together with the software for solving the coupled electrodynamic equations.

  2. Supercurrent in van der Waals Josephson junction

    PubMed Central

    Yabuki, Naoto; Moriya, Rai; Arai, Miho; Sata, Yohta; Morikawa, Sei; Masubuchi, Satoru; Machida, Tomoki

    2016-01-01

    Supercurrent flow between two superconductors with different order parameters, a phenomenon known as the Josephson effect, can be achieved by inserting a non-superconducting material between two superconductors to decouple their wavefunctions. These Josephson junctions have been employed in fields ranging from digital to quantum electronics, yet their functionality is limited by the interface quality and use of non-superconducting material. Here we show that by exfoliating a layered dichalcogenide (NbSe2) superconductor, the van der Waals (vdW) contact between the cleaved surfaces can instead be used to construct a Josephson junction. This is made possible by recent advances in vdW heterostructure technology, with an atomically flat vdW interface free of oxidation and inter-diffusion achieved by eliminating all heat treatment during junction preparation. Here we demonstrate that this artificially created vdW interface provides sufficient decoupling of the wavefunctions of the two NbSe2 crystals, with the vdW Josephson junction exhibiting a high supercurrent transparency. PMID:26830754

  3. Van der Waals Interactions Involving Proteins

    NASA Technical Reports Server (NTRS)

    Roth, Charles M.; Neal, Brian L.; Lenhoff, Abraham M.

    1996-01-01

    Van der Waals (dispersion) forces contribute to interactions of proteins with other molecules or with surfaces, but because of the structural complexity of protein molecules, the magnitude of these effects is usually estimated based on idealized models of the molecular geometry, e.g., spheres or spheroids. The calculations reported here seek to account for both the geometric irregularity of protein molecules and the material properties of the interacting media. Whereas the latter are found to fall in the generally accepted range, the molecular shape is shown to cause the magnitudes of the interactions to differ significantly from those calculated using idealized models. with important consequences. First, the roughness of the molecular surface leads to much lower average interaction energies for both protein-protein and protein-surface cases relative to calculations in which the protein molecule is approximated as a sphere. These results indicate that a form of steric stabilization may be an important effect in protein solutions. Underlying this behavior is appreciable orientational dependence, one reflection of which is that molecules of complementary shape are found to exhibit very strong attractive dispersion interactions. Although this has been widely discussed previously in the context of molecular recognition processes, the broader implications of these phenomena may also be important at larger molecular separations, e.g., in the dynamics of aggregation, precipitation, and crystal growth.

  4. The neuropsychiatric ailment of Vincent Van Gogh

    PubMed Central

    Bhattacharyya, Kalyan B.; Rai, Saurabh

    2015-01-01

    Vincent Van Gogh is one of the most celebrated creative artists of all time. All his life, he was afflicted by some kind of neurological or psychiatric disorder, which remains a mystery even today. Many historians and his personal physicians believe that he suffered from epilepsy while others felt that he was affected by Ménière's disease. Features such as hypergraphia, atypical sexuality, and viscosity of thinking suggest the possibility of Gastaut-Geschwind phenomenon, a known complication of complex partial seizure. On the contrary, some historians feel that he was forced to sever his right ear in order to get relief from troublesome tinnitus, a complication of Ménière's disease. He was addicted to the liquor absinthe, which is known to lead to xanthopsia, and many authorities argue that this was the reason for his penchant for the deep and bright yellow color in many of his paintings. Others have suggested the possibility of bipolar disorder, sunstroke, acute intermittent porphyria, and digitalis toxicity as well. PMID:25745302

  5. [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. PMID:24681990

  6. Modern theory of van der Waals interactions

    NASA Astrophysics Data System (ADS)

    Dobson, John

    2014-03-01

    van der Waals (vdW, dispersion) interactions are important in diverse areas such as colloid, surface and nano science, cohesion of molecular crystals, and biomolecular science. They also provide competition in experiments to discover the fifth fundamental force.While vdW interactions have been understood in principle for a century, their quantitative first-principles prediction and modelling down to chemical contact separations have proven stubbornly difficult because the quantal many-electron problem is involved. After some brief historical material, the current state of the art will be discussed with particular reference to several approaches: pairwise additive, perturbative quantum chemical, vdW-DF, Lifshitz-like scattering, RPA-like, Adiabatic Connection Fluctuation Dissipation / Time Dependent DFT based etc.. A potentially useful classification will be introduced to aid in understanding the physical causes of departures from pairwise additivity, that is from the usual sum of C6R-6 contributions. These departures result in non-standard power law decays of nanostructure vdW interactions as a function of separation D, as well as surprising dependences of the attraction on the number, N, of atoms within each vdW-interacting fragment. Some further recent results on non-additivity will also be presented. Work supported by an Australian Research Council Discovery Grant.

  7. Van der Waals Interactions in Aspirin

    NASA Astrophysics Data System (ADS)

    Reilly, Anthony; Tkatchenko, Alexandre

    2015-03-01

    The ability of molecules to yield multiple solid forms, or polymorphs, has significance for diverse applications ranging from drug design and food chemistry to nonlinear optics and hydrogen storage. In particular, aspirin has been used and studied for over a century, but has only recently been shown to have an additional polymorphic form, known as form II. Since the two observed solid forms of aspirin are degenerate in terms of lattice energy, kinetic effects have been suggested to determine the metastability of the less abundant form II. Here, first-principles calculations provide an alternative explanation based on free-energy differences at room temperature. The explicit consideration of many-body van der Waals interactions in the free energy demonstrates that the stability of the most abundant form of aspirin is due to a subtle coupling between collective electronic fluctuations and quantized lattice vibrations. In addition, a systematic analysis of the elastic properties of the two forms of aspirin rules out mechanical instability of form II as making it metastable.

  8. 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.

  9. 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. PMID:21797072

  10. van't Hoff-van der Waals osmotic pressure and energy transformers.

    PubMed

    Zener, C; Levenson, W

    1983-07-01

    We find the van't Hoff relations between osmotic pressure, freezing point depression, and boiling point elevation provide a clue on how, by using salt solutions, one may lower the cost of extracting power from low-grade heat sources. In particular, the ratio of 7 between the heat of evaporation and the heat of freezing of pure water suggests a chemical system that raises 7-fold the temperature difference between heat source and heat sink, while decreasing by the same factor the heat flux. Heat exchangers dominate the cost of heat engines operating upon low-grade heat. Their area for a fixed power output is inversely proportional to the available temperature differential. Herein lies the potential for a great cost reduction. We show that the simple van der Waals concept of a gas of hard elastic spheres suffices to understand the colligative properties of salt solutions, at least up to the concentration of the eutectic composition. This concept enables us to physically interpret the thermodynamic processes during the concentration of salt solutions by evaporation and during the mixing of ice and solid salt hydrates at their eutectic temperature. These are identical to the thermodynamic processes taking place during the isothermal compression and expansion of gases in pumps and in turbines.

  11. van't Hoff-van der Waals osmotic pressure and energy transformers.

    PubMed

    Zener, C; Levenson, W

    1983-07-01

    We find the van't Hoff relations between osmotic pressure, freezing point depression, and boiling point elevation provide a clue on how, by using salt solutions, one may lower the cost of extracting power from low-grade heat sources. In particular, the ratio of 7 between the heat of evaporation and the heat of freezing of pure water suggests a chemical system that raises 7-fold the temperature difference between heat source and heat sink, while decreasing by the same factor the heat flux. Heat exchangers dominate the cost of heat engines operating upon low-grade heat. Their area for a fixed power output is inversely proportional to the available temperature differential. Herein lies the potential for a great cost reduction. We show that the simple van der Waals concept of a gas of hard elastic spheres suffices to understand the colligative properties of salt solutions, at least up to the concentration of the eutectic composition. This concept enables us to physically interpret the thermodynamic processes during the concentration of salt solutions by evaporation and during the mixing of ice and solid salt hydrates at their eutectic temperature. These are identical to the thermodynamic processes taking place during the isothermal compression and expansion of gases in pumps and in turbines. PMID:16593343

  12. van't Hoff-van der Waals osmotic pressure and energy transformers

    PubMed Central

    Zener, Clarence; Levenson, William

    1983-01-01

    We find the van't Hoff relations between osmotic pressure, freezing point depression, and boiling point elevation provide a clue on how, by using salt solutions, one may lower the cost of extracting power from low-grade heat sources. In particular, the ratio of 7 between the heat of evaporation and the heat of freezing of pure water suggests a chemical system that raises 7-fold the temperature difference between heat source and heat sink, while decreasing by the same factor the heat flux. Heat exchangers dominate the cost of heat engines operating upon low-grade heat. Their area for a fixed power output is inversely proportional to the available temperature differential. Herein lies the potential for a great cost reduction. We show that the simple van der Waals concept of a gas of hard elastic spheres suffices to understand the colligative properties of salt solutions, at least up to the concentration of the eutectic composition. This concept enables us to physically interpret the thermodynamic processes during the concentration of salt solutions by evaporation and during the mixing of ice and solid salt hydrates at their eutectic temperature. These are identical to the thermodynamic processes taking place during the isothermal compression and expansion of gases in pumps and in turbines. PMID:16593343

  13. 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

  14. Van de Graaff based positron source production

    NASA Astrophysics Data System (ADS)

    Lund, Kasey Roy

    The anti-matter counterpart to the electron, the positron, can be used for a myriad of different scientific research projects to include materials research, energy storage, and deep space flight propulsion. Currently there is a demand for large numbers of positrons to aid in these mentioned research projects. There are different methods of producing and harvesting positrons but all require radioactive sources or large facilities. Positron beams produced by relatively small accelerators are attractive because they are easily shut down, and small accelerators are readily available. A 4MV Van de Graaff accelerator was used to induce the nuclear reaction 12C(d,n)13N in order to produce an intense beam of positrons. 13N is an isotope of nitrogen that decays with a 10 minute half life into 13C, a positron, and an electron neutrino. This radioactive gas is frozen onto a cryogenic freezer where it is then channeled to form an antimatter beam. The beam is then guided using axial magnetic fields into a superconducting magnet with a field strength up to 7 Tesla where it will be stored in a newly designed Micro-Penning-Malmberg trap. Several source geometries have been experimented on and found that a maximum antimatter beam with a positron flux of greater than 0.55x10 6 e+s-1 was achieved. This beam was produced using a solid rare gas moderator composed of krypton. Due to geometric restrictions on this set up, only 0.1-1.0% of the antimatter was being frozen to the desired locations. Simulations and preliminary experiments suggest that a new geometry, currently under testing, will produce a beam of 107 e+s-1 or more.

  15. Correction to Van Moorselaar et al. (2015).

    PubMed

    2015-11-01

    Reports an error in "Forgotten But Not Gone: Retro-Cue Costs and Benefits in a Double-Cueing Paradigm Suggest Multiple States in Visual Short-Term Memory" by Dirk van Moorselaar, Christian N. L. Olivers, Jan Theeuwes, Victor A. F. Lamme and Ilja G. Sligte (Journal of Experimental Psychology: Learning, Memory, and Cognition, Advanced Online Publication, Apr 13, 2015, np). The Figure 2 (b) legend printed incorrectly. The correct figure is present in the erratum. All versions of this article have been corrected. (The following abstract of the original article appeared in record 2015-15672-001.) Visual short-term memory (VSTM) performance is enhanced when the to-be-tested item is cued after encoding. This so-called retro-cue benefit is typically accompanied by a cost for the noncued items, suggesting that information is lost from VSTM upon presentation of a retrospective cue. Here we assessed whether noncued items can be restored to VSTM when made relevant again by a subsequent second cue. We presented either 1 or 2 consecutive retro-cues (80% valid) during the retention interval of a change-detection task. Relative to no cue, a valid cue increased VSTM capacity by 2 items, while an invalid cue decreased capacity by 2. Importantly, when a second, valid cue followed an invalid cue, capacity regained 2 items, so that performance was back on par. In addition, when the second cue was also invalid, there was no extra loss of information from VSTM, suggesting that those items that survived a first invalid cue, automatically also survived a second. We conclude that these results are in support of a very versatile VSTM system, in which memoranda adopt different representational states depending on whether they are deemed relevant now, in the future, or not at all. We discuss a neural model that is consistent with this conclusion.

  16. Correction to Van Moorselaar et al. (2015).

    PubMed

    2015-11-01

    Reports an error in "Forgotten But Not Gone: Retro-Cue Costs and Benefits in a Double-Cueing Paradigm Suggest Multiple States in Visual Short-Term Memory" by Dirk van Moorselaar, Christian N. L. Olivers, Jan Theeuwes, Victor A. F. Lamme and Ilja G. Sligte (Journal of Experimental Psychology: Learning, Memory, and Cognition, Advanced Online Publication, Apr 13, 2015, np). The Figure 2 (b) legend printed incorrectly. The correct figure is present in the erratum. All versions of this article have been corrected. (The following abstract of the original article appeared in record 2015-15672-001.) Visual short-term memory (VSTM) performance is enhanced when the to-be-tested item is cued after encoding. This so-called retro-cue benefit is typically accompanied by a cost for the noncued items, suggesting that information is lost from VSTM upon presentation of a retrospective cue. Here we assessed whether noncued items can be restored to VSTM when made relevant again by a subsequent second cue. We presented either 1 or 2 consecutive retro-cues (80% valid) during the retention interval of a change-detection task. Relative to no cue, a valid cue increased VSTM capacity by 2 items, while an invalid cue decreased capacity by 2. Importantly, when a second, valid cue followed an invalid cue, capacity regained 2 items, so that performance was back on par. In addition, when the second cue was also invalid, there was no extra loss of information from VSTM, suggesting that those items that survived a first invalid cue, automatically also survived a second. We conclude that these results are in support of a very versatile VSTM system, in which memoranda adopt different representational states depending on whether they are deemed relevant now, in the future, or not at all. We discuss a neural model that is consistent with this conclusion. PMID:26213836

  17. Detection of vanC1 gene transcription in vancomycin-susceptible Enterococcus faecalis.

    PubMed

    Moura, Tiane Martin de; Cassenego, Ana Paula Vaz; Campos, Fabrício Souza; Ribeiro, Andrea Machado Leal; Franco, Ana Cláudia; d'Azevedo, Pedro Alves; Frazzon, Jeverson; Frazzon, Ana Paula Guedes

    2013-06-01

    Here we report the presence and expression levels of the vanC1 and vanC(2/3) genes in vancomycin-susceptible strains of Enterococcus faecalis. The vanC1 and vanC(2/3) genes were located in the plasmid DNA and on the chromosome, respectively. Specific mRNA of the vanC1 gene was detected in one of these strains. Additionally, analysis of the vanC gene sequences showed that these genes are related to the vanC genes of Enterococcus gallinarum and Enterococcus casseliflavus. The presence of vanC genes is useful for the identification of E. gallinarum and E. casseliflavus. Moreover, this is the first report of vanC mRNA in E. faecalis.

  18. [Implication of lead poisoning in psychopathology of Vincent van Gogh].

    PubMed

    González Luque, F J; Montejo González, A L

    1997-01-01

    The authors, by means of documental research, study the possibility that the physical and psychic symptoms of Vincent van Gogh may have been due to chronic lead poisoning. The technique and materials used by Van Gogh are analysed as the cause of repeated exposure to lead as well as the possible means of penetration of the metal. Through historical-biographical analysis, the progressive symptoms of the illness are compared with those of lead poisoning. The authors conclude that the excessive and continuous use by Van Gogh of pigments which were highly toxic due to their high lead content, such as white lead (lead carbonate) and yellow chrome (lead chromium), could have penetrated his organism by digestive system (primarily) in minimal daily amounts, giving rise to a clinical condition of chronic lead poisoning. This type of poisoning coincides with the clinical symptoms Van Gogh describes in his autographed letters: initial debilitation, stomatitis with loss of teeth, recurring abdominal pains, anaemia (with a "plumbic" skin tone), neuropathy of the radial and saturnine encephalopathy including epileptic crises, progressive character changes and periods of delirium. The clinical symptoms shown by Van Gogh meet present criteria for diagnosis of Organic Mental Disorder due to cerebral lesion or somatic illness (F.06; CIE-10) (DSM-IV-R), and Organic Character Disorder (F.07; CIE-10) (DSM-IV-R).

  19. Eos Interviews Robert Van Hook, Former AGU Interim Executive Director

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2010-08-01

    Robert Van Hook, who served as AGU's interim executive director since January 2009, led the organization during a transition period that began with the retirement of long-serving executive director A. F. (“Fred”) Spilhaus Jr. Van Hook's tenure concluded on 30 August when Christine McEntee assumed her position as AGU's new executive director (see Eos, 91(17), 153, 156, 2010). During his tenure at AGU, which overlapped with a global economic recession, Van Hook helped to guide the organization through key structural governance changes, strategic planning, and upgrades in technology, human resources, and accounting. He also helped to revitalize public outreach and member services, among many other efforts. Van Hook, president of Transition Management Consulting, recently reflected upon his tenure, the transition period, and the future of AGU. Van Hook credits AGU's strong volunteer leadership—including past presidents Tim Killeen and Tim Grove, current president Mike McPhaden, and president-elect Carol Finn—for courage in moving the organization through a successful transition. “They were the ones who shoved the boat off from the shore. I was lucky enough to be invited into the boat,” he said. He also credits the staff for their resiliency and commitment to supporting AGU's science.

  20. Van der Waals interaction in uniaxial anisotropic media

    NASA Astrophysics Data System (ADS)

    Kornilovitch, Pavel E.

    2013-01-01

    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.

  1. 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. PMID:23234868

  2. The "van Zijl" Jurassic geomagnetic reversal revisited

    NASA Astrophysics Data System (ADS)

    Courtillot, V.; Moulin, M.; fluteau, F.; Valet, J. M.

    2011-12-01

    In 1962, van Zijl and colleagues published the first record of one of the oldest reversals available in some detail. This was a Jurassic reversal recorded in the basaltic sequence of the Lesotho, part of the Karoo large igneous province. In 2003, Prévot and colleagues provided a second more accurate record (Bushmen's Pass section - BP). We have recently obtained two other detailed records from two sections (Naude's Nek NN and Oxbow-Moteng Pass OM). The reversal is therefore now recorded in some detail in three sections which are up to 200km away from each other (the age being at ~180Ma). The reversal is recorded as 23 transitional directions over 130m in NN. When lava flows having recorded the (statistically) same direction to within a few degrees, which likely belong to the same cooling unit, are regrouped (directional groups or DG), we are left with 10 independent directions. There are 13 transitional directions over 160m in OM, and 8 distinct, independent directions. And in the BP section, there are 35 transitional directions over 200m, and 21 independent directions. The three records are remarkably similar and at the same time complementary. They can be used to retrace the VGP reversal path in a unique and robust way. Directions display 4 strong clusters which are interpreted as times of slow secular variation and/or fast extrusion rate of the lava. The path jumps from transitional reversed to transitional normal directions with no intermediate directions between 30°S and 30°N (once the path has been restored to proper geographical coordinates applicable to the ~180Ma reconstruction of the continents). We have applied several techniques to determine the evolution of relative paleo-intensities during the reversal; all these methods converge to the same conclusion, with intensities lower by a factor close to 10 between the core of the reversal and the time when full normal polarity has been regained, with intermediate intensities just before and after the core

  3. 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

  4. Van der woude syndrome with short review of the literature.

    PubMed

    Deshmukh, Pallavi K; Deshmukh, Kiran; Mangalgi, Anand; Patil, Subhash; Hugar, Deepa; Kodangal, Saraswathi Fakirappa

    2014-01-01

    Van der Woude syndrome (VWS) is a rare autosomal dominant condition with high penetrance and variable expression. Clinical manifestation of this autosomal dominant clefting syndrome includes bilateral midline lower lip pits, cleft lip, and cleft palate along with hypodontia. These congenital lip pits appear as a malformation in the vermilion border of the lip, with or without excretion. Discomfort caused by spontaneous or induced drainage of saliva/mucus when pressure is applied or during a meal as well as poor aesthetic match is one of the main complaints of patients with congenital lip fistula. The pits are treated by surgical resection. Dentists should be aware of the congenital lip pits as in Van der Woude syndrome because they have been reported to be associated with a variety of malformations or other congenital disorders. Here, the authors report a rare case of Van der Woude syndrome with short review of the literature. PMID:25050184

  5. A cartography of the van der Waals territories.

    PubMed

    Alvarez, Santiago

    2013-06-28

    The distribution of distances from atoms of a particular element E to a probe atom X (oxygen in most cases), both bonded and intermolecular non-bonded contacts, has been analyzed. In general, the distribution is characterized by a maximum at short E···X distances corresponding to chemical bonds, followed by a range of unpopulated distances--the van der Waals gap--and a second maximum at longer distances--the van der Waals peak--superimposed on a random distribution function that roughly follows a d(3) dependence. The analysis of more than five million interatomic "non-bonded" distances has led to the proposal of a consistent set of van der Waals radii for most naturally occurring elements, and its applicability to other element pairs has been tested for a set of more than three million data, all of them compared to over one million bond distances.

  6. Spontaneous stacking faults in van der Waals heterostructures

    NASA Astrophysics Data System (ADS)

    Boussinot, G.

    2016-08-01

    The rapid developments in the manipulation of two-dimensional monoatomic layers such as graphene or h-BN allow one to create heterostructures consisting of possibly many chemically different layers, stacked owing to van der Waals attraction. We propose a Frenkel-Kontorova model including a transverse degree of freedom in order to describe local deformations in these heterostructures. We study the case where two dissimilar monolayers are alternatively stacked, and find that stacking faults may emerge spontaneously for a large enough number of stacked layers as a result of the competition between adhesion and elastic energies. This symmetry-breaking transition should become of fundamental importance for the description of three-dimensional van der Waals heterostructures as soon as a precise control on the lattice orientation of the van der Waals layers is achieved.

  7. van der Waals interactions between excited atoms in generic environments

    NASA Astrophysics Data System (ADS)

    Barcellona, Pablo; Passante, Roberto; Rizzuto, Lucia; Buhmann, Stefan Yoshi

    2016-07-01

    We consider the van der Waals force involving excited atoms in general environments, constituted by magnetodielectric bodies. We develop a dynamical approach studying the dynamics of the atoms and the field, mutually coupled. When only one atom is excited, our dynamical theory suggests that for large distances the van der Waals force acting on the ground-state atom is monotonic, while the force acting in the excited atom is spatially oscillating. We show how this latter force can be related to the known oscillating Casimir-Polder force on an excited atom near a (ground-state) body. Our force also reveals a population-induced dynamics: for times much larger that the atomic lifetime the atoms will decay to their ground states leading to the van der Waals interaction between ground-state atoms.

  8. Collisional stabilization of van der Waals states of ozone.

    PubMed

    Ivanov, Mikhail V; Babikov, Dmitri

    2011-05-01

    The mixed quantum-classical theory developed earlier [M. Ivanov and D. Babikov, J. Chem. Phys. 134, 144107 (2011)] is employed to treat the collisional energy transfer and the ro-vibrational energy flow in a recombination reaction that forms ozone. Assumption is that the van der Waals states of ozone are formed in the O + O(2) collisions, and then stabilized into the states of covalent well by collisions with bath gas. Cross sections for collision induced dissociation of van der Waals states of ozone, for their stabilization into the covalent well, and for their survival in the van der Waals well are computed. The role these states may play in the kinetics of ozone formation is discussed.

  9. Collisional stabilization of van der Waals states of ozone

    NASA Astrophysics Data System (ADS)

    Ivanov, Mikhail V.; Babikov, Dmitri

    2011-05-01

    The mixed quantum-classical theory developed earlier [M. Ivanov and D. Babikov, J. Chem. Phys. 134, 144107 (2011)] is employed to treat the collisional energy transfer and the ro-vibrational energy flow in a recombination reaction that forms ozone. Assumption is that the van der Waals states of ozone are formed in the O + O2 collisions, and then stabilized into the states of covalent well by collisions with bath gas. Cross sections for collision induced dissociation of van der Waals states of ozone, for their stabilization into the covalent well, and for their survival in the van der Waals well are computed. The role these states may play in the kinetics of ozone formation is discussed.

  10. 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

  11. Van der Waals stacked 2D layered materials for optoelectronics

    NASA Astrophysics Data System (ADS)

    Zhang, Wenjing; Wang, Qixing; Chen, Yu; Wang, Zhuo; Wee, Andrew T. S.

    2016-06-01

    The band gaps of many atomically thin 2D layered materials such as graphene, black phosphorus, monolayer semiconducting transition metal dichalcogenides and hBN range from 0 to 6 eV. These isolated atomic planes can be reassembled into hybrid heterostructures made layer by layer in a precisely chosen sequence. Thus, the electronic properties of 2D materials can be engineered by van der Waals stacking, and the interlayer coupling can be tuned, which opens up avenues for creating new material systems with rich functionalities and novel physical properties. Early studies suggest that van der Waals stacked 2D materials work exceptionally well, dramatically enriching the optoelectronics applications of 2D materials. Here we review recent progress in van der Waals stacked 2D materials, and discuss their potential applications in optoelectronics.

  12. In Vivo Characterization of the Activation and Interaction of the VanR-VanS Two-Component Regulatory System Controlling Glycopeptide Antibiotic Resistance in Two Related Streptomyces Species

    PubMed Central

    Novotna, Gabriela Balikova; Kwun, Min Jung

    2015-01-01

    The VanR-VanS two-component system is responsible for inducing resistance to glycopeptide antibiotics in various bacteria. We have performed a comparative study of the VanR-VanS systems from two streptomyces strains, Streptomyces coelicolor and Streptomyces toyocaensis, to characterize how the two proteins cooperate to signal the presence of antibiotics and to define the functional nature of each protein in each strain background. The results indicate that the glycopeptide antibiotic inducer specificity is determined solely by the differences between the amino acid sequences of the VanR-VanS two-component systems present in each strain rather than by any inherent differences in general cell properties, including cell wall structure and biosynthesis. VanR of S. coelicolor (VanRsc) functioned with either sensor kinase partner, while VanR of S. toyocaensis (VanRst) functioned only with its cognate partner, S. toyocaensis VanS (VanSst). In contrast to VanRsc, which is known to be capable of phosphorylation by acetylphosphate, VanRst could not be activated in vivo independently of a VanS sensor kinase. A series of amino acid sequence modifications changing residues in the N-terminal receiver (REC) domain of VanRst to the corresponding residues present in VanRsc failed to create a protein capable of being activated by VanS of S. coelicolor (VanSsc), which suggests that interaction of the response regulator with its cognate sensor kinase may require a region more extended than the REC domain. A T69S amino acid substitution in the REC domain of VanRst produced a strain exhibiting weak constitutive resistance, indicating that this particular amino acid may play a key role for VanS-independent phosphorylation in the response regulator protein. PMID:26711760

  13. 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.

  14. Photonic analog of a van Hove singularity in metamaterials

    NASA Astrophysics Data System (ADS)

    Cortes, Cristian L.; Jacob, Zubin

    2013-07-01

    We introduce the photonic analog of electronic van Hove singularities (VHS) in artificial media (metamaterials) with hyperbolic dispersion. Unlike photonic and electronic crystals, the VHS in metamaterials are unrelated to the underlying periodicity and occur due to slow-light modes in the structure. We show that the VHS characteristics are manifested in the near-field local density of optical states in spite of the losses, dispersion, and finite unit-cell size of the hyperbolic metamaterial. Finally, we show that this work should lead to quantum, thermal, nanolasing, and biosensing applications of van Hove singularities in hyperbolic metamaterials achievable by current fabrication technology.

  15. Curves of growth for van der Waals broadened spectral lines

    NASA Technical Reports Server (NTRS)

    Park, C.

    1980-01-01

    Curves of growth are evaluated for a spectral line broadened by the van der Waals interactions during collisions. The growth of the equivalent widths of such lines is shown to be dependent on the product of the perturber density and the 6/10 power of the van der Waals potential coefficient. When the parameter is small, the widths grow as the 1/2 power of the optical depth as they do for the Voigt profile: but when the parameter is large, they grow as 2/3 power and, hence, faster than the Voigt profile. An approximate analytical expression for the computed growth characteristics is given.

  16. 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.

  17. [Van Neck-Odelberg disease. Report of two cases].

    PubMed

    Nagy, Örs; Zuh, Sándor-György; Kovács, Attila; Sólyom, Árpád; Sólyom, Réka; Gergely, István

    2016-05-22

    Osteochondritis ischiopubica or van Neck-Odelberg disease is characterized by atypical ossification of the ischiopubic synchondrosis. Clinical symptoms are usually pain, limping and limited range of motion of the hip joint. Radiologic images may be confused with the possibility of fracture, tumor or inflammation. In some cases it may be difficult to set up the accurate diagnosis, and during the diagnostic process it is essential that van Neck-Odelberg disease should be considered. In this paper the authors draw attention to this rare disorder and they present the history of two patients who posed diagnostic difficulties.

  18. 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.

  19. 78 FR 53816 - Culturally Significant Objects Imported for Exhibition Determinations: “Van Gogh Repetitions”

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ... Culturally Significant Objects Imported for Exhibition Determinations: ``Van Gogh Repetitions'' SUMMARY... that the objects to be included in the exhibition ``Van Gogh Repetitions,'' imported from abroad for temporary exhibition within the United States, are of cultural significance. The objects are...

  20. 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.

  1. Twelve-Month Evaluation of UPS Diesel Hybrid Electric Delivery Vans

    SciTech Connect

    Lammert, M.

    2009-12-01

    Results of an NREL study of a parallel hybrid electric-diesel propulsion system in United Parcel Service-operated delivery vans show that the hybrids had higher fuel economy than standard diesel vans.

  2. Genetic Analysis of a Chromosomal Region Containing vanA and vanB, Genes Required for Conversion of Either Ferulate or Vanillate to Protocatechuate in Acinetobacter†

    PubMed Central

    Segura, Ana; Bünz, Patricia V.; D’Argenio, David A.; Ornston, L. Nicholas

    1999-01-01

    VanA and VanB form an oxygenative demethylase that converts vanillate to protocatechuate in microorganisms. Ferulate, an abundant phytochemical, had been shown to be metabolized through a vanillate intermediate in several Pseudomonas isolates, and biochemical evidence had indicated that vanillate also is an intermediate in ferulate catabolism by Acinetobacter. Genetic evidence supporting this conclusion was obtained by characterization of mutant Acinetobacter strains blocked in catabolism of both ferulate and vanillate. Cloned Acinetobacter vanA and vanB were shown to be members of a chromosomal segment remote from a supraoperonic cluster containing other genes required for completion of the catabolism of ferulate and its structural analogs, caffeate and coumarate, through protocatechuate. The nucleotide sequence of DNA containing vanA and vanB demonstrated the presence of genes that, on the basis of nucleotide sequence similarity, appeared to be associated with transport of aromatic compounds, metabolism of such compounds, or iron scavenging. Spontaneous deletion of 100 kb of DNA containing this segment does not impede the growth of cells with simple carbon sources other than vanillate or ferulate. Additional spontaneous mutations blocking vanA and vanB expression were shown to be mediated by IS1236, including insertion of the newly discovered composite transposon Tn5613. On the whole, vanA and vanB appear to be located within a nonessential genetic region that exhibits considerable genetic malleability in Acinetobacter. The overall organization of genes neighboring Acinetobacter vanA and vanB, including a putative transcriptional regulatory gene that is convergently transcribed and overlaps vanB, is conserved in Pseudomonas aeruginosa but has undergone radical rearrangement in other Pseudomonas species. PMID:10348863

  3. Gene vanXYC encodes D,D -dipeptidase (VanX) and D,D-carboxypeptidase (VanY) activities in vancomycin-resistant Enterococcus gallinarum BM4174.

    PubMed

    Reynolds, P E; Arias, C A; Courvalin, P

    1999-10-01

    VanX and VanY have strict D,D-dipeptidase and D,D-carboxypeptidase activity, respectively, that eliminates production of peptidoglycan precursors ending in D-alanyl-D-alanine (D-Ala-D-Ala) in glycopeptide-resistant enterococci in which the C-terminal D-Ala residue has been replaced by D-lactate. Enterococcus gallinarum BM4174 synthesizes peptidoglycan precursors ending in D-Ala-D-serine (D-Ala-D-Ser) essential for VanC-type vancomycin resistance. Insertional inactivation of the vanC-1 gene encoding the ligase that catalyses synthesis of D-Ala-D-Ser has a polar effect on both D, D-dipeptidase and D,D-carboxypeptidase activities. The open reading frame downstream from vanC-1 encoded a soluble protein designated VanXYC (Mr 22 318), which had both of these activities. It had 39% identity and 74% similarity to VanY in an overlap of 158 amino acids, and contained consensus sequences for binding zinc, stabilizing the binding of substrate and catalysing hydrolysis that are present in both VanX- and VanY-type enzymes. It had very low dipeptidase activity against D-Ala-D-Ser, unlike VanX, and no activity against UDP-MurNAc-pentapeptide[D-Ser], unlike VanY. The introduction of plasmid pAT708(vanC-1,XYC) or pAT717(vanXYC) into vancomycin-susceptible Enterococcus faecalis JH2-2 conferred low-level vancomycin resistance only when D-Ser was present in the growth medium. The peptidoglycan precursor profiles of E. faecalis JH2-2 and JH2-2(pAT708) and JH2-2(pAT717) indicated that the function of VanXYC was hydrolysis of D-Ala-D-Ala and removal of D-Ala from UDP-MurNAc-pentapeptide[D-Ala]. VanC-1 and VanXYC were essential, but not sufficient, for vancomycin resistance.

  4. [Van Gogh, the stigmatized man of the society].

    PubMed

    Bénézech, M; Addad, M

    1984-11-01

    After briefly recalling the labelling theory of deviant behaviour (criminality, mental pathology), the authors set out to illustrate the relationship between madness and stigma by analyzing the biography and letters of Vincent Van Gogh. They conclude that the artist interiorized the process of family and social stigmatization owing to a particular psychological preparatory ground originating from the circumstances of his birth.

  5. 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.

  6. Research at the BNL Tandem Van de Graaff Facility, 1980

    SciTech Connect

    Not Available

    1981-03-01

    Research programs at the Brookhaven Van de Graaff accelerators are summarized. Major accomplishments of the laboratory are discussed including quasielastic reactions, high-spin spectroscopy, yrast spectra, fusion reactions, and atomic physics. The outside user program at the Laboratory is discussed. Research proposed for 1981 is outlined. (GHT)

  7. 75 FR 52534 - Su Van Ho: Debarment Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Su Van Ho: Debarment Order AGENCY: Food and Drug... Dade'' fish and 461 cartons of Pineapple Brand Betel Nut as ``Frozen Palmnut.'' On or about...

  8. 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

  9. 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.

  10. Charging belt noise in a Van de Graaff accelerator

    SciTech Connect

    Trainor, T.A.

    1988-01-01

    With the aid of a Fast Fourier Transformer (FFT) spectrum analyzer it has been possible to decompose Van de Graaff terminal voltage noise into components that can be related to various properties of the charging belt. One consequence has been the elimination of the fundamental belt frequency component by a novel belt charge transfer device. 18 figs.

  11. Statistical complexity, virial expansion, and van der Waals equation

    NASA Astrophysics Data System (ADS)

    Pennini, F.; Plastino, A.

    2016-09-01

    We investigate the notion of LMC statistical complexity with regards to a real gas and in terms of the second virial coefficient. The ensuing results are applied to the van der Waals equation. Interestingly enough, one finds a complexity-interpretation for the associated phase transition.

  12. Wnt signalling: a moving picture emerges from van gogh.

    PubMed

    Heisenberg, Carl-Philipp; Tada, Masazumi

    2002-02-19

    Recent studies on vertebrate homologues of the van gogh/strabismus (vang/stbm) gene, a key player in planar cell polarity signalling in Drosophila, show that vang/stbm is involved in patterning and morphogenesis during vertebrate gastrulation where it modulates two distinct Wnt signals.

  13. 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.

  14. Excited nucleon as a van der Waals system of partons

    SciTech Connect

    Jenkovszky, L. L.; Muskeyev, A. O. Yezhov, S. N.

    2012-06-15

    Saturation in deep inelastic scattering (DIS) and deeply virtual Compton scattering (DVCS) is associated with a phase transition between the partonic gas, typical of moderate x and Q{sup 2}, and partonic fluid appearing at increasing Q{sup 2} and decreasing Bjorken x. We suggest the van der Waals equation of state to describe properly this phase transition.

  15. [Van Gogh, the stigmatized man of the society].

    PubMed

    Bénézech, M; Addad, M

    1984-11-01

    After briefly recalling the labelling theory of deviant behaviour (criminality, mental pathology), the authors set out to illustrate the relationship between madness and stigma by analyzing the biography and letters of Vincent Van Gogh. They conclude that the artist interiorized the process of family and social stigmatization owing to a particular psychological preparatory ground originating from the circumstances of his birth. PMID:6398974

  16. The Evaluation of the Parameters in the van Deemter Equation.

    ERIC Educational Resources Information Center

    Moody, Harvey W.

    1982-01-01

    Describes experiment expanding on principles behind measuring efficiency of chromatographic columns and allowing calculation of parameters in the van Deemter equation. Easily accomplished in a three-hour period using a gas chromatograph in which gas flow can be changed and measured. Mathematical solutions can be attained with programmable…

  17. 46 CFR 194.10-15 - Magazine van construction.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Magazine van construction. 194.10-15 Section 194.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-15 Magazine...

  18. 46 CFR 194.10-15 - Magazine van construction.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Magazine van construction. 194.10-15 Section 194.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-15 Magazine...

  19. 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…

  20. The Evolving Space Weather System—Van Allen Probes Contribution

    NASA Astrophysics Data System (ADS)

    Zanetti, L. J.; Mauk, B. H.; Fox, N. J.; Barnes, R. J.; Weiss, M.; Sotirelis, T. S.; Raouafi, N.-E.; Kessel, R. L.; Becker, H. N.

    2014-10-01

    The overarching goal and purpose of the study of space weather is clear—to understand and address the issues caused by solar disturbances on humans and technological systems. Space weather has evolved in the past few decades from a collection of concerned agencies and researchers to a critical function of the National Weather Service of NOAA. The general effects have also evolved from the well-known telegraph disruptions of the mid-1800s to modern day disturbances of the electric power grid, communications and navigation, human spaceflight and spacecraft systems. The last two items in this list, and specifically the effects of penetrating radiation, were the impetus for the space weather broadcast implemented on NASA's Van Allen Probes' twin pair of satellites, launched in August of 2012 and orbiting directly through Earth's severe radiation belts. The Van Allen Probes mission, formerly the Radiation Belt Storm Probes (RBSP), was renamed soon after launch to honor the discoverer of Earth's radiation belts at the beginning of the space age, the late James Van Allen (the spacecraft themselves are still referred to as RBSP-A and RBSP-B). The Van Allen Probes are one part of NASA's Living With a Star program formulated to advance the scientific understanding of the connection between solar disturbances, the resulting heliospheric conditions, and their effects on the geospace and Earth environment.

  1. Obituary: Leon Van Speybroeck, 1935-2002

    NASA Astrophysics Data System (ADS)

    Gorenstein, Paul; Tananbaum, Harvey Dale

    2003-12-01

    Leon Van Speybroeck, a master designer of X-ray telescope mirrors and the telescope scientist for the Chandra X-ray Observatory, died in Newton, Massachusetts, on 25 December 2002, shortly after learning that he had metastatic melanoma. Leon was born on 27 August 1935 in Wichita, Kansas. His father, Paul, was Assistant Treasurer and head of the accounting department at Beech Aircraft, and his mother, Anna Florence (Utley), was a homemaker. Both parents died in 1996. Leon's younger sister, Saundra, is a nurse and his younger brother, John, is a surgeon. Leon received a BS in 1957 and a PhD in 1965, both in physics, from MIT. His PhD thesis, ``Elastic Electron-Deuteron Scattering at High Momentum Transfer," was carried out under the supervision of Henry Kendall and Jerome Friedman. Leon spent two more years at MIT as a research associate. In 1967, he was hired by American Science and Engineering (AS&E) in Cambridge, Massachusetts, and joined the X-ray astronomy group led by Riccardo Giacconi, who received the 2002 Nobel Prize in Physics for contributions to astrophysics that led to the discovery of cosmic X-ray sources. Leon soon became involved in the design and construction of high-resolution, grazing-incidence X-ray telescopes, starting with the Apollo Telescope Mount flown on NASA's Skylab from 1973 to 1974. A series of high-resolution X-ray images of the solar corona led to dramatic changes in ideas about the solar corona, with new emphasis on magnetic dynamo processes. When the Smithsonian Astrophysical Observatory and the Harvard College Observatory morphed into the Harvard-Smithsonian Center for Astrophysics (CfA) in 1973, Leon, with Giacconi and other senior X-ray astronomers from AS&E, joined the CfA and formed the high-energy astrophysics division. Leon guided the design and development of the X-ray mirrors on NASA's Einstein Observatory, which was flown from 1978 to 1981 as the first cosmic X-ray observatory with an imaging telescope. Along the way, he

  2. Did Van Gogh have Ménière's disease?

    PubMed

    Martin, C

    2011-09-01

    Very surprising diagnoses have sometimes been made of the illness from which Vincent van Gogh suffered. Most of them can be safely ignored; the diagnosis of Ménière's disease, however, put forward by K. I. Arenberg, deserves attention. This diagnosis was first criticized in a doctoral thesis in 1992 in the university of Saint-Etienne (France), and again in a book published by Henri André Martin in 1994, and the present study is based on these. Analyzing van Gogh's pathology presupposes awareness of the family context in which he lived, his eventful life, his artistic career and of his correspondence, which notably provides no support for a diagnosis of Ménière's disease. Analysis, indeed, enables Ménière's disease to be categorically eliminated in favor of temporal epilepsy, as confirmed in 1956 by Gastaut following the diagnosis initially made half a century earlier by Dr Rey. Van Gogh's illness is an example of the contradictory changes in affect, behavior and personality to be observed in epileptic patients. Absinth intoxication doubtless aggravated van Gogh's epilepsy and may account for certain prolonged episodes of confusion. It would be wrong, however, to speak of alcoholic dementia rather than of a probable epileptic psychosis or other pathology such as hallucinatory psychosis, or delirious attack, either isolated or related to late-onset schizophrenia. Apart from certain episodes of severe mental disorder, however, van Gogh's exceptional creativity was maintained up to the very end. Like any other artist, his temperament was expressed in his art, exalted rather than impaired by his illness.

  3. 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. PMID:26887249

  4. Detection of seasonal asymptomatic dermatophytes in Van cats

    PubMed Central

    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. PMID:26887249

  5. Did Van Gogh have Ménière's disease?

    PubMed

    Martin, C

    2011-09-01

    Very surprising diagnoses have sometimes been made of the illness from which Vincent van Gogh suffered. Most of them can be safely ignored; the diagnosis of Ménière's disease, however, put forward by K. I. Arenberg, deserves attention. This diagnosis was first criticized in a doctoral thesis in 1992 in the university of Saint-Etienne (France), and again in a book published by Henri André Martin in 1994, and the present study is based on these. Analyzing van Gogh's pathology presupposes awareness of the family context in which he lived, his eventful life, his artistic career and of his correspondence, which notably provides no support for a diagnosis of Ménière's disease. Analysis, indeed, enables Ménière's disease to be categorically eliminated in favor of temporal epilepsy, as confirmed in 1956 by Gastaut following the diagnosis initially made half a century earlier by Dr Rey. Van Gogh's illness is an example of the contradictory changes in affect, behavior and personality to be observed in epileptic patients. Absinth intoxication doubtless aggravated van Gogh's epilepsy and may account for certain prolonged episodes of confusion. It would be wrong, however, to speak of alcoholic dementia rather than of a probable epileptic psychosis or other pathology such as hallucinatory psychosis, or delirious attack, either isolated or related to late-onset schizophrenia. Apart from certain episodes of severe mental disorder, however, van Gogh's exceptional creativity was maintained up to the very end. Like any other artist, his temperament was expressed in his art, exalted rather than impaired by his illness. PMID:21616739

  6. 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

  7. Obituary: Leon Van Speybroeck, 1935-2002

    NASA Astrophysics Data System (ADS)

    Gorenstein, Paul; Tananbaum, Harvey Dale

    2003-12-01

    Leon Van Speybroeck, a master designer of X-ray telescope mirrors and the telescope scientist for the Chandra X-ray Observatory, died in Newton, Massachusetts, on 25 December 2002, shortly after learning that he had metastatic melanoma. Leon was born on 27 August 1935 in Wichita, Kansas. His father, Paul, was Assistant Treasurer and head of the accounting department at Beech Aircraft, and his mother, Anna Florence (Utley), was a homemaker. Both parents died in 1996. Leon's younger sister, Saundra, is a nurse and his younger brother, John, is a surgeon. Leon received a BS in 1957 and a PhD in 1965, both in physics, from MIT. His PhD thesis, ``Elastic Electron-Deuteron Scattering at High Momentum Transfer," was carried out under the supervision of Henry Kendall and Jerome Friedman. Leon spent two more years at MIT as a research associate. In 1967, he was hired by American Science and Engineering (AS&E) in Cambridge, Massachusetts, and joined the X-ray astronomy group led by Riccardo Giacconi, who received the 2002 Nobel Prize in Physics for contributions to astrophysics that led to the discovery of cosmic X-ray sources. Leon soon became involved in the design and construction of high-resolution, grazing-incidence X-ray telescopes, starting with the Apollo Telescope Mount flown on NASA's Skylab from 1973 to 1974. A series of high-resolution X-ray images of the solar corona led to dramatic changes in ideas about the solar corona, with new emphasis on magnetic dynamo processes. When the Smithsonian Astrophysical Observatory and the Harvard College Observatory morphed into the Harvard-Smithsonian Center for Astrophysics (CfA) in 1973, Leon, with Giacconi and other senior X-ray astronomers from AS&E, joined the CfA and formed the high-energy astrophysics division. Leon guided the design and development of the X-ray mirrors on NASA's Einstein Observatory, which was flown from 1978 to 1981 as the first cosmic X-ray observatory with an imaging telescope. Along the way, he

  8. 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

  9. 76 FR 58649 - Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List Van Rossem...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-21

    ... In our November 15, 1994, Candidate Notice of Review (59 FR 58982), we included van Rossem's gull... van Rossem's gull-billed tern. This decision was finalized on December 5, 1996 (61 FR 64481). Since... data suggested van Rossem's gull-billed terns bred in Mexico (van Rossem and Hachisuka 1937, p....

  10. Integratie van opleiding en onderzoek in de opleiding tot psychiater.

    PubMed

    Verhoeven, W M; Goessens, L F; van den Berg, Y W; Tuinier, S

    1999-03-01

    In the training program for residents in psychiatry, scientific education and participation in research projects are relatively underdeveloped. This may result in a gap between recently acquired scientific knowledge and its implementation in clinical practice. Since the start of the residency training in psychiatry in 1989 in the Vincent van Gogh Institute for Psychiatry, several research lines have been developed especially concerning dimensional diagnostic procedures, evaluation of treatment effects, stress and psychopathology, pharmacokinetics of psychotropic compounds and disordered impulse and aggression regulation. It is concluded that active participation in research projects by both psychiatrists and residents in psychiatry is increasingly mandatory due to social-economic en scientific developments. Despite several countervailing factors, the Vincent van Gogh Institute for Psychiatry has succeeded in the creation of a scientific orientation in the residency program resulting in a number of publications.

  11. [Neuropsychiatry and creativity: "Starry night" of Van Gogh].

    PubMed

    Abundes-Corona, Rodolfo Arturo; Corona Vázquez, Teresa

    2014-01-01

    The life of Vincent van Gogh (1853-1890) has been studied thoroughly by humanists and scientists alike. His biography is an archetype of the relationship between creativity and disease. In 1956, Henri Gastaut defined his diagnosis as temporal lobe epilepsy. The artist was known for an eccentric personality and unpredictable mood, with recurrent psychotic bouts through the last two years of his life. Several authors have considered the possibility that van Gogh also suffered from bipolar affective disorder. We conducted a biographical and epistolary review with the objective of analyzing the complexity of his disease and the effects it had on his art, which ultimately placed him as one of the greatest geniuses in art.

  12. Generalized van der Waals density functional theory for nonuniform polymers

    SciTech Connect

    Patra, Chandra N.; Yethiraj, Arun

    2000-01-15

    A density functional theory is presented for the effect of attractions on the structure of polymers at surfaces. The theory treats the ideal gas functional exactly, and uses a weighted density approximation for the hard chain contribution to the excess free energy functional. The attractive interactions are treated using a van der Waals approximation. The theory is in good agreement with computer simulations for the density profiles at surfaces for a wide range of densities and temperatures, except for low polymer densities at low temperatures where it overestimates the depletion of chains from the surface. This deficiency is attributed to the neglect of liquid state correlations in the van der Waals term of the free energy functional. (c) 2000 American Institute of Physics.

  13. Photovoltaic effect in an electrically tunable van der Waals heterojunction.

    PubMed

    Furchi, Marco M; Pospischil, Andreas; Libisch, Florian; Burgdörfer, Joachim; Mueller, Thomas

    2014-08-13

    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.

  14. van der Waals explosion of cold Rydberg clusters

    NASA Astrophysics Data System (ADS)

    Faoro, R.; Simonelli, C.; Archimi, M.; Masella, G.; Valado, M. M.; Arimondo, E.; Mannella, R.; Ciampini, D.; Morsch, O.

    2016-03-01

    We report on the direct measurement in real space of the effect of the van der Waals forces between individual Rydberg atoms on their external degrees of freedom. Clusters of Rydberg atoms with interparticle distances of around 5 μ m are created by first generating a small number of seed excitations in a magneto-optical trap, followed by off-resonant excitation that leads to a chain of facilitated excitation events. After a variable expansion time the Rydberg atoms are field ionized, and from the arrival time distributions the size of the Rydberg cluster after expansion is calculated. Our experimental results agree well with a numerical simulation of the van der Waals explosion.

  15. Charge Transfer Excitons at van der Waals Interfaces.

    PubMed

    Zhu, Xiaoyang; Monahan, Nicholas R; Gong, Zizhou; Zhu, Haiming; Williams, Kristopher W; Nelson, Cory A

    2015-07-01

    The van der Waals interfaces of molecular donor/acceptor or graphene-like two-dimensional (2D) semiconductors are central to concepts and emerging technologies of light-electricity interconversion. Examples include, among others, solar cells, photodetectors, and light emitting diodes. A salient feature in both types of van der Waals interfaces is the poorly screened Coulomb potential that can give rise to bound electron-hole pairs across the interface, i.e., charge transfer (CT) or interlayer excitons. Here we address common features of CT excitons at both types of interfaces. We emphasize the competition between localization and delocalization in ensuring efficient charge separation. At the molecular donor/acceptor interface, electronic delocalization in real space can dictate charge carrier separation. In contrast, at the 2D semiconductor heterojunction, delocalization in momentum space due to strong exciton binding may assist in parallel momentum conservation in CT exciton formation. PMID:26001297

  16. Van Allen Probes: Resolving Fundamental Physics with Practical Consequences

    NASA Astrophysics Data System (ADS)

    Ukhorskiy, Aleksandr; Sibeck, David; Fox, Nicola; Mauk, Barry; Kessel, Ramona

    The Van Allen Probes twin spacecraft were launched on 30 August 2012 into nearly identical, 1.1 x 5.8 Re elliptical, low inclination (10°) Earth orbits with one of the two spacecraft lapping the other about every 2.5 months. The goal of the mission is to provide understanding of how populations of relativistic electrons and penetrating ions in space form or change in response to variable inputs of energy from the Sun. In this paper we overview the new understanding and discoveries of the Van Allen Probes science investigations since the operational mission began on 1 November 2012, which include formation of multiple coherently ordered structures within the outer electron belt and new persistent “zebra stripes” in the inner electron belt.

  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. Van der Waals interaction-tuned heat transfer in nanostructures.

    PubMed

    Sun, Tao; Wang, Jianxiang; Kang, Wei

    2013-01-01

    Interfaces usually impede heat transfer in heterogeneous structures. Recent experiments show that van der Waals (vdW) interactions can significantly enhance thermal conductivity parallel to the interface of a bundle of nanoribbons compared to a single layer of freestanding nanoribbon. In this paper, by simulating heat transfer in nanostructures based on a model of nonlinear one-dimensional lattices interacting via van der Waals interactions, we show that the vdW interface interaction can adjust the thermal conductivity parallel to the interface. The efficiency of the adjustment depends on the intensity of interactions and temperature. The nonlinear dependence of the conductivity on the intensity of interactions agrees well with experimental results for carbon nanotube bundles, multi-walled carbon nanotubes, multi-layer graphene, and nanoribbons.

  19. 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

  20. Quantum field theory of van der Waals friction

    SciTech Connect

    Volokitin, A. I.; Persson, B. N. J.

    2006-11-15

    van der Waals friction between two semi-infinite solids, and between a small neutral particle and semi-infinite solid is studied using thermal quantum field theory in the Matsubara formulation. We show that the friction to linear order in the sliding velocity can be obtained from the equilibrium Green functions and that our treatment can be extended for bodies with complex geometry. The calculated friction agrees with the friction obtained using a dynamical modification of the Lifshitz theory, which is based on the fluctuation-dissipation theorem. We show that it should be possible to measure the van der Waals friction in noncontact friction experiment using state-of-the-art equipment.

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

    SciTech Connect

    Alvaro Calle Cordon, Enrique Ruiz Arriola

    2011-12-01

    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 computed 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.

  2. Persistent hysteresis in graphene-mica van der Waals heterostructures.

    PubMed

    Mohrmann, Jens; Watanabe, Kenji; Taniguchi, Takashi; Danneau, Romain

    2015-01-01

    We report the study of electronic transport in graphene-mica van der Waals heterostructures. We have designed various graphene field-effect devices in which mica is utilized as a substrate and/or gate dielectric. When mica is used as a gate dielectric we observe a very strong positive gate voltage hysteresis of the resistance, which persists in samples that were prepared in a controlled atmosphere down to even millikelvin temperatures. In a double-gated mica-graphene-hBN van der Waals heterostructure, we found that while a strong hysteresis occurred when mica was used as a substrate/gate dielectric, the same graphene sheet on mica substrate no longer showed hysteresis when the charge carrier density was tuned through a second gate with the hBN dielectric. While this hysteretic behavior could be useful for memory devices, our findings confirm that the environment during sample preparation has to be controlled strictly.

  3. The wing of madness: the illness of Vincent van Gogh.

    PubMed

    Morrant, J C

    1993-09-01

    This paper briefly describes some aspects of Vincent van Gogh's life and attitudes. It discusses absinthe and several psychodynamic factors that may have contributed to his psychotic episodes at Arles, when he cut off his ear. It discusses Vincent's descriptions of his illness, especially at Saint Rémy de Provence and concludes that he probably suffered from partial complex seizures (temporal lobe epilepsy) with manic depressive mood swings aggravated by absinthe, brandy, nicotine and turpentine.

  4. Computerized Comparison and Analysis of Vincent van Gogh's Painting Brushstrokes

    NASA Astrophysics Data System (ADS)

    Wang, James Z.

    2009-03-01

    With advanced digitization techniques, museums have routinely begun to assemble vast digital libraries of images of their collections. These images can be analyzed by computers to assist art historians for a number of tasks. In our work, we focus on three challenges: artist identification, dating of an art work, and finding distinguishing features among artists. Two complementary approaches were taken: (1) the analysis of the geometric statistics based on the extracted individual brushstroke, and (2) the modeling of overall brushstroke texture. These approaches aim at assisting art historians in comparing a painting or parts of a painting to a group of paintings based on multiple criteria. Statistical methods have been used to compare groups of paintings. Each painting image is divided into subimages. Individual brushstrokes are segmented automatically. Geometric features, including the curvature, the overall orientation, and the size, are computed for each brushstroke. We also compute the features representing the interactivity of the brushstrokes extracted. The statistics, including average and standard deviation, of those features are used to model certain aspects of the artist's brushstrokes. For capturing the local brushstroke texture, we first apply a wavelet transform to the image. A spatial model, the 2-D hidden Markov model, is used to model the texture features of each subimage. The methods have shown to be able to distinguish van Gogh paintings and non van Gogh paintings to a great extent. The techniques can provide clues for the dating of van Gogh paintings. A comparison of the van Gogh paintings, Monticelli's paintings, and paintings by contemporary artists provides insights on their similarities and differences. The analysis has provided numerical statistics for further studying these and other paintings.

  5. A reappraisal of the possible seizures of Vincent van Gogh.

    PubMed

    Hughes, John R

    2005-06-01

    The tragic life of Vincent van Gogh is summarized, emphasizing his early departure from formal education, failure as a successful salesman in the art world, attempt at religious studies, difficulty with female and family relationships, return to the art world, and tendencies toward extremes of poor nutrition or near self-starvation and excessive drinking and smoking. In Paris he joined the Impressionists, but drank very heavily both absinthe and cognac. Southward he went to Arles and was joined by Paul Gauguin, with whom he had major personality problems, causing van Gogh to cut off part of his left ear. He experienced paranoid ideation and confinement in mental institutions in Arles, and then returned to Paris and onto Auvers-sur-Oise, where he committed suicide at age 37. Possible physical diagnoses include glaucoma, Meniere's disease, acute intermittent porphyria, and chronic lead poisoning, but these diagnoses seem unlikely. Possible psychiatric diagnoses include borderline personality disorder, anxiety-depressive disorder with episodes of depression and hypomania, and also paranoid schizophrenia. Van Gogh did not have spontaneous seizures and, therefore, did not have epilepsy. Before he began to drink heavily, when he was near starvation, he had "fainting fits," and after drinking, especially absinthe, a convulsant drug, he continued to have similar attacks. His episodes of unconsciousness can be well explained by chronic malnutrition and alcohol abuse, only possibly exacerbated by drinking large quantities of absinthe. Although van Gogh is an excellent example of the Geschwind syndrome, at times associated with temporal lobe epilepsy, this fact does not establish such an epilepsy. Thus, the syndrome is an orphan without the parent condition.

  6. Isolated lower lip fistulas in Van der Woude syndrome.

    PubMed

    Etöz, Osman A; Etöz, Abdullah

    2009-09-01

    Van der Woude syndrome (VWS) is a dominantly inherited disease of orofacial region. Characteristic features of this syndrome are bilateral lower lip sinuses along with cleft lip or palate deformity. However, isolated lower lip pits in VWS without any cleft syndrome is uncommon. Lip pits in VWS are usually asymptomatic; however, patients may complain of watery drainage and/or infection. In this report, asymptomatic isolated lower lip sinuses without any cleft syndrome in a patient and his father are presented. PMID:19816310

  7. Van der Woude syndrome with an unusual intraoral finding.

    PubMed

    Sarode, Gargi S; Desai, Rajiv S; Sarode, Sachin C; Kulkarni, Meena A

    2011-01-01

    Orofacial manifestations of Van der Woude syndrome (VWS) include cleft lip or palate, lower lip pits, hypodontia, hypernasal voice, cleft or bifid uvula, syngnathia, narrow high arched palate, and ankyloglossia. Extraoral manifestations include limb anomalies, popliteal webs, accessory nipples, congenital heart defects, and Hirschsprung disease. We report an interesting case of VWS with characteristic orofacial features along with an unusual additional finding of fusion of primary mandibular left lateral incisor and canine in a 7-year-old boy. PMID:21525698

  8. Van der Waals interactions: accuracy of pair potential approximations.

    PubMed

    Cole, Milton W; Kim, Hye-Young; Liebrecht, Michael

    2012-11-21

    Van der Waals interactions between single atoms and solids are discussed for the regime of large separation. A commonly employed approximation is to evaluate this interaction as a sum of two-body interactions between the adatom and the constituent atoms of the solid. The resulting potentials are here compared with known results in various geometries. Analogous comparisons are made for diatomic molecules near either single atoms or semi-infinite surfaces and for triatomic molecules' interactions with single atoms. PMID:23181315

  9. 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 excess 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.

  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. PMID:27610412

  11. 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.

  12. Nonadiabatic Van der Pol oscillations in molecular transport

    NASA Astrophysics Data System (ADS)

    Kartsev, Alexey; Verdozzi, Claudio; Stefanucci, Gianluca

    2014-01-01

    The force exerted by the electrons on the nuclei of a current-carrying molecular junction can be manipulated to engineer nanoscale mechanical systems. In the adiabatic regime a peculiarity of these forces is negative friction, responsible for Van der Pol oscillations of the nuclear coordinates. In this work we study the robustness of the Van der Pol oscillations against high-frequency sources. For this purpose we go beyond the adiabatic approximation and perform full Ehrenfest dynamics simulations. The numerical scheme implements a mixed quantum-classical algorithm for open systems and is capable to deal with arbitrary time-dependent driving fields. We find that the Van der Pol oscillations are extremely stable. The nonadiabatic electron dynamics distorts the trajectory in the momentum-coordinate phase space but preserves the limit cycles in an average sense. We further show that high-frequency fields change both the oscillation amplitudes and the average nuclear positions. By switching the fields off at different times one obtains cycles of different amplitudes which attain the limit cycle only after considerably long times.

  13. 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

  14. 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.

  15. 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.

  16. Comment to the Article by van Arensbergen and van den Besselaar "The Selection of Scientific Talent in the Allocation of Research Grants"

    ERIC Educational Resources Information Center

    Maessen, K. M. H.

    2012-01-01

    The article entitled "The selection of scientific talent in the allocation of research grants" by van Arensbergen and van den Besselaar published in "Higher Education Policy" 25/3 (2012) is based on research that both researchers carried out on behalf of The Netherlands Organisation for Scientific Research. In this comment, we want to address…

  17. 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

  18. [Development of a simplified assay for detection of van gene harbored enterococci using the automated BD MAX platform].

    PubMed

    Sakanashi, Daisuke; Yamagishi, Yuka; Miyazaki, Narimi; Suzuki, Takayoshi; Ohno, Tomoko; Yamada, Atsuko; Koita, Isao; Miyajima, Setsuo; Suematsu, Hiroyuki; Mikamo, Hiroshige

    2014-10-01

    We developed and evaluated of multiplex real-time PCR assay for detection of vancomycin-resistant genes (vanA, vanB, vanC1 and vanC2/C3) using the new, fully automated BD MAX platform. Ct value analyses of real-time PCR simultaneous repeatability test have showed the usefulness; coefficient of variation: CV (%) were determined 2.09%, 1.72%, 1.41% and 1.52% with vanA, vanB, vanC1 and vanC2/C3, respectively. We also evaluated with 43 strains of enterococci were characterized by conventional PCR method; 4/4 for vanA-positive, 14/14 for vanB-positive, 1/1 for vanB plus vanC1-positive, 6/6 for vanC1-positive, 4/4 for vanC2/C3- positive and 14/14 for all-van gene-negative strains were identified correctly. This assay was automatically performing before and after PCR operations previously done manually by operator, such as DNA extraction, sample dispensing and gel electrophoresis or the ethidium bromide dyeing. As a result, work burden and the risk of the contamination were largely reduced and were shortened to about half for measurement time. We conclude that this assay could greatly contribute to efficient and rapid detection of vancomycin-resistant genes.

  19. Substrate Inhibition of VanA by d-Alanine Reduces Vancomycin Resistance in a VanX-Dependent Manner.

    PubMed

    van der Aart, Lizah T; Lemmens, Nicole; van Wamel, Willem J; van Wezel, Gilles P

    2016-08-01

    The increasing resistance of clinical pathogens against the glycopeptide antibiotic vancomycin, a last-resort drug against infections with Gram-positive pathogens, is a major problem in the nosocomial environment. Vancomycin inhibits peptidoglycan synthesis by binding to the d-Ala-d-Ala terminal dipeptide moiety of the cell wall precursor lipid II. Plasmid-transferable resistance is conferred by modification of the terminal dipeptide into the vancomycin-insensitive variant d-Ala-d-Lac, which is produced by VanA. Here we show that exogenous d-Ala competes with d-Lac as a substrate for VanA, increasing the ratio of wild-type to mutant dipeptide, an effect that was augmented by several orders of magnitude in the absence of the d-Ala-d-Ala peptidase VanX. Liquid chromatography-mass spectrometry (LC-MS) analysis showed that high concentrations of d-Ala led to the production of a significant amount of wild-type cell wall precursors, while vanX-null mutants produced primarily wild-type precursors. This enhanced the efficacy of vancomycin in the vancomycin-resistant model organism Streptomyces coelicolor, and the susceptibility of vancomycin-resistant clinical isolates of Enterococcus faecium (VRE) increased by up to 100-fold. The enhanced vancomycin sensitivity of S. coelicolor cells correlated directly to increased binding of the antibiotic to the cell wall. Our work offers new perspectives for the treatment of diseases associated with vancomycin-resistant pathogens and for the development of drugs that target vancomycin resistance. PMID:27270282

  20. Rhythmic brushstrokes distinguish van Gogh from his contemporaries: findings via automated brushstroke extraction.

    PubMed

    Li, Jia; Yao, Lei; Hendriks, Ella; Wang, James Z

    2012-06-01

    Art historians have long observed the highly characteristic brushstroke styles of Vincent van Gogh and have relied on discerning these styles for authenticating and dating his works. In our work, we compared van Gogh with his contemporaries by statistically analyzing a massive set of automatically extracted brushstrokes. A novel extraction method is developed by exploiting an integration of edge detection and clustering-based segmentation. Evidence substantiates that van Gogh's brushstrokes are strongly rhythmic. That is, regularly shaped brushstrokes are tightly arranged, creating a repetitive and patterned impression. We also found that the traits that distinguish van Gogh's paintings in different time periods of his development are all different from those distinguishing van Gogh from his peers. This study confirms that the combined brushwork features identified as special to van Gogh are consistently held throughout his French periods of production (1886-1890).

  1. Rhythmic brushstrokes distinguish van Gogh from his contemporaries: findings via automated brushstroke extraction.

    PubMed

    Li, Jia; Yao, Lei; Hendriks, Ella; Wang, James Z

    2012-06-01

    Art historians have long observed the highly characteristic brushstroke styles of Vincent van Gogh and have relied on discerning these styles for authenticating and dating his works. In our work, we compared van Gogh with his contemporaries by statistically analyzing a massive set of automatically extracted brushstrokes. A novel extraction method is developed by exploiting an integration of edge detection and clustering-based segmentation. Evidence substantiates that van Gogh's brushstrokes are strongly rhythmic. That is, regularly shaped brushstrokes are tightly arranged, creating a repetitive and patterned impression. We also found that the traits that distinguish van Gogh's paintings in different time periods of his development are all different from those distinguishing van Gogh from his peers. This study confirms that the combined brushwork features identified as special to van Gogh are consistently held throughout his French periods of production (1886-1890). PMID:22516651

  2. van der Waals coefficients for systems with ultracold polar alkali-metal molecules

    NASA Astrophysics Data System (ADS)

    Żuchowski, P. S.; Kosicki, M.; Kodrycka, M.; Soldán, P.

    2013-02-01

    A systematic study of the leading isotropic van der Waals coefficients for the alkali-metal atom+molecule and molecule+molecule systems is presented. Dipole moments and static and dynamic dipole polarizabilities are calculated employing high-level quantum chemistry calculations. The dispersion, induction, and rotational parts of the isotropic van der Waals coefficient are evaluated. The known van der Waals coefficients are then used to derive characteristics essential for simple models of the collisions involving the corresponding ultracold polar molecules.

  3. Project Overview: United Parcel Service's Second-Generation Hybrid-Electric Delivery Vans (Fact Sheet)

    SciTech Connect

    Not Available

    2011-11-01

    This fact sheet describes UPS second generation hybrid-electric delivery vehicles as compared to conventional delivery vehicles. Medium-duty commercial vehicles such as moving trucks, beverage-delivery trucks, and package-delivery vans consume almost 2,000 gal of fuel per year on average. United Parcel Service (UPS) operates hybrid-electric package-delivery vans to reduce the fuel use and emissions of its fleet. In 2008, the National Renewable Energy Laboratory's (NREL's) Fleet Test and Evaluation Team evaluated the first generation of UPS' hybrid delivery vans. These hybrid vans demonstrated 29%-37% higher fuel economy than comparable conventional diesel vans, which contributed to UPS' decision to add second-generation hybrid vans to its fleet. The Fleet Test and Evaluation Team is now evaluating the 18-month, in-service performance of 11 second-generation hybrid vans and 11 comparable conventional diesel vans operated by UPS in Minneapolis, Minnesota. The evaluation also includes testing fuel economy and emissions at NREL's Renewable Fuels and Lubricants (ReFUEL) Laboratory and comparing diesel particulate filter (DPF) regeneration. In addition, a followup evaluation of UPS' first-generation hybrid vans will show how those vehicles performed over three years of operation. One goal of this project is to provide a consistent comparison of fuel economy and operating costs between the second-generation hybrid vans and comparable conventional vans. Additional goals include quantifying the effects of hybridization on DPF regeneration and helping UPS select delivery routes for its hybrid vans that maximize the benefits of hybrid technology. This document introduces the UPS second-generation hybrid evaluation project. Final results will be available in mid-2012.

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

    SciTech Connect

    Benali, Anouar; Shulenburger, Luke; Romero, Nichols A.; Kim, Jeongnim; von Lilienfeld, O. Anatole

    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.

  5. Interim Project Results: United Parcel Service's Second-Generation Hybrid-Electric Delivery Vans (Fact Sheet)

    SciTech Connect

    Not Available

    2012-01-01

    This fact sheet describes the performance evaluation of United Parcel Service's second-generation hybrid-electric delivery vans. The Fleet Test and Evaluation Team at the National Renewable Energy Laboratory (NREL) is evaluating the 18-month, in-service performance of 11 of these vans along with 11 comparable conventional diesel vans operating in Minneapolis, Minnesota. As a complement to the field study, the team recently completed fuel economy and emissions testing at NREL's Renewable Fuels and Lubricants (ReFUEL) laboratory.

  6. Combating vancomycin resistance in bacteria: targeting the D-ala-D-ala dipeptidase VanX.

    PubMed

    Crowder, Michael W

    2006-06-01

    In the past 20 years, vancomycin and other glycopeptide antibiotics have been administered to patients with Streptococcal and Staphylococcal infections that were resistant to all other antibiotics or to patients who were allergic to penicillins and cephalosporins. After extensive use of vancomycin and other glycopeptide antibiotics in humans, several strains of Enterococcus have developed high-level vancomycin resistance (collectively called VRE, vancomycin-resistant Enterococcus), and this resistance phenotype has spread to other organisms. The spread of vancomycin resistance to other pathogens and, potentially, to bacterial strains on the CDC's bioterrorism watch list is a major biomedical concern. Bacteria most often become resistant to vancomycin by acquiring a transposon containing genes that encode for a number of proteins, five of which are essential for the high-level resistance phenotype. The five essential gene products are called VanR, VanS, VanH, VanA, and VanX. Previous studies have shown that the inactivation of VanX results in an organism that is sensitive to vancomycin and that VanX is an excellent inhibitor target. In this review the known inhibitors and structural and mechanistic properties of VanX will be discussed. These data will be used to offer suggestions for novel, rationally-designed or -redesigned inhibitors, which could potentially be used in combination with existing glycopeptide antibiotics as a treatment for vancomycin-resistant bacterial infections.

  7. 46 CFR 195.11-10 - Design and construction of portable vans.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... escape, arrangement, interior construction, and electrical installations. (d) Power vans are those outfitted with electrical power generating machinery or batteries providing electrical power for other...

  8. 46 CFR 195.11-10 - Design and construction of portable vans.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... escape, arrangement, interior construction, and electrical installations. (d) Power vans are those outfitted with electrical power generating machinery or batteries providing electrical power for other...

  9. 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.

  10. Van der Waals interaction between two crossed carbon nanotubes.

    PubMed

    Zhbanov, Alexander I; Pogorelov, Evgeny G; Chang, Yia-Chung

    2010-10-26

    The analytical expressions for the van der Waals potential energy and force between two crossed carbon nanotubes are presented. The Lennard-Jones potential between pairs of carbon atoms and the smeared-out approximation suggested by L. A. Girifalco (J. Phys. Chem. 1992, 96, 858) were used. The exact formula is expressed in terms of rational and elliptical functions. The potential and force for carbon nanotubes were calculated. The uniform potential curves for single- and multiwall nanotubes were plotted. The equilibrium distance, maximal attractive force, and potential energy have been evaluated. PMID:20863127

  11. van Hove singularities in disordered multichannel quantum wires and nanotubes

    NASA Astrophysics Data System (ADS)

    Hügle, S.; Egger, R.

    2002-11-01

    We present a theory for the van Hove singularity (VHS) in the tunneling density of states (TDOS) of disordered multichannel quantum wires, in particular multiwall carbon nanotubes. We assume close-by gates that screen off electron-electron interactions. Diagrammatic perturbation theory within the noncrossing approximation yields analytical expressions governing the disorder-induced broadening and shift of VHS's as new subbands are opened. This problem is nontrivial because the (lowest-order) Born approximation breaks down close to the VHS. Interestingly, compared to the bulk case, the boundary TDOS shows drastically altered VHS's, even in the clean limit.

  12. Reconstruction of the lower lip in Van der Woude syndrome.

    PubMed

    Bozkurt, Mehmet; Kulahci, Yalcin; Zor, Fatih; Kapi, Emin; Yucetas, Altan

    2009-04-01

    Van der Woude syndrome (VWS) is a congenital disease characterized by labial cysts, accessory salivary glands, congenital lower lip pits, fistula, and paramedian sinuses, and is often accompanied by cleft lip and palate. VWS is an autosomal dominant craniofacial syndrome, which represents only lower lip pits due to variable gene expression. The principles of VWS surgery include excision of lower lip pits and accessory glands, reconstruction of the lip and nose, and correction of accompanying anomalies. In this article, we present a technique with dermal allograft reconstruction to prevent deformities after excision of the accessory gland in the lower lip pit. PMID:19325355

  13. Lower lip pits: van der woude or kabuki syndrome?

    PubMed

    David-Paloyo, Ferri P; Yang, Xuecai; Lin, Ju-Li; Wong, Fen-Hwa; Wu-Chou, Yah-Huei; Lo, Lun-Jou

    2014-11-01

    Kabuki syndrome (KS) is a multiple congenital anomaly/mental retardation syndrome with characteristic facial features. Despite more than 350 documented cases and recent correlation of MLL2 mutations as a genetic cause, its full clinical spectrum is still being defined. This report describes two patients who were initially diagnosed with Van der Woude syndrome (VWS) based on the presence of lower lip pits. However, this finding can occur with KS, albeit infrequently. For patients with lower lip pits, a thorough evaluation should be made to distinguish between VWS and KS, as there are differences in long-term prognosis. PMID:24088119

  14. Nonadditivity of van der Waals forces on liquid surfaces

    NASA Astrophysics Data System (ADS)

    Venkataram, Prashanth S.; Whitton, Jeremy D.; Rodriguez, Alejandro W.

    2016-09-01

    We present an approach for modeling nanoscale wetting and dewetting of textured solid surfaces that exploits recently developed, sophisticated techniques for computing exact long-range dispersive van der Waals (vdW) or (more generally) Casimir forces in arbitrary geometries. We apply these techniques to solve the variational formulation of the Young-Laplace equation and predict the equilibrium shapes of liquid-vacuum interfaces near solid gratings. We show that commonly employed methods of computing vdW interactions based on additive Hamaker or Derjaguin approximations, which neglect important electromagnetic boundary effects, can result in large discrepancies in the shapes and behaviors of liquid surfaces compared to exact methods.

  15. The Van Fault, Eastern Turkey: A Preliminary Geological Slip Rate

    NASA Astrophysics Data System (ADS)

    Mackenzie, D.; Elliott, J. R.; Altunel, E.; Kurban, Y.; Walker, R. T.; Parsons, B.

    2014-12-01

    We present a preliminary quaternary slip-rate study on the Van fault, the source of the 2011 Mw7.1 reverse-slip earthquake which caused heavy damage to the cities of Van and Ercis, eastern Turkey. From the InSAR solution, we see a strong depth cut-off at 10km depth, above which there was no slip on the fault. We have carried out an investigation of the geomorphological expression of the fault in quaternary material, to determine whether the fault reaches the surface and, if so, whether this upper section could fail in an earthquake. On the western segment of the Van fault, we observe quaternary scarps coincident with the surface projection of the fault segment identified by InSAR, which displace quaternary alluvial fan and lake-bed deposits. These are coincident with the observation of fault gouge in quaternary deposits at a road cutting, providing evidence for a fault reaching the surface and suggesting that the upper section is capable of rupturing seismically. We use structure-from-motion photogrammetry, differential GPS and terrestrial LiDAR to determine offsets on two generations of fault scarps, and the creep offsets from the period following the earthquake. Preliminary radiocarbon and OSL dates from two uplifted terrace surfaces allow us to estimate a late quaternary geological slip-rate for the fault. Following the GPS and InSAR solution of Dogan et al. 2014 (GRL v41,i7), we also present field evidence and satellite image observations confirming the presence of a splay fault within the northern suburbs of Van city, which experienced creep following the 2011 earthquake. This fault is observed to be particularly evident in the early high resolution satellite imagery from the declassified CORONA missions, highlighting the potential for these datasets in identifying faults in areas now covered by urban sprawl. It remains unclear whether this fault could fail seismically. The fault which failed in 2011 is a north dipping reverse fault, unmapped prior to the

  16. Dandy-Walker malformation in Ellis-van Creveld syndrome.

    PubMed

    Zangwill, K M; Boal, D K; Ladda, R L

    1988-09-01

    We report on 2 Old Order Amish patients with Ellis-van Creveld (EvC) syndrome and the Dandy-Walker malformation; a similar case is noted in the literature. Pedigree analysis of our patients documents extensive inbreeding in successive generations. Considering the rarity of EvC syndrome and Dandy-Walker malformation as isolated malformations, the appearance of both in our 2 patients plus the patient in the literature suggests that Dandy-Walker malformation may be a manifestation in the EvC syndrome. However, in this isolate the coincidental occurrence of 2 rare recessive traits cannot be excluded. PMID:3223493

  17. Ellis-van Creveld syndrome: A rare clinical entity.

    PubMed

    Kamal, Reet; Dahiya, Parveen; Kaur, Simerpreet; Bhardwaj, Rohit; Chaudhary, Karun

    2013-01-01

    Ellis-van Creveld (EVC) syndrome is a genetic disorder with autosomal recessive transmission, which may clinically present as small stature, short limbs, fine sparse hair, hypoplastic fingernails, multiple musculofibrous frenula, conical teeth, hypoplasia of the enamel, hypodontia, and malocclusion. Heart defects, especially abnormalities of atrial septation, have been found in about 60% of cases. The mutation in EVC and EVC2 gene is responsible for this syndrome. The presence of multiple orodental findings makes this syndrome important for dentists. The aim of this article is to present a rare case of EVC syndrome in a 10-year-old girl along with the review of literature.

  18. Ellis-van Creveld Syndrome with Sagittal Craniosynostosis.

    PubMed

    Fischer, Andrew S; Weathers, William M; Wolfswinkel, Erik M; Bollo, Robert J; Hollier, Larry H; Buchanan, Edward P

    2015-06-01

    Ellis-van Creveld syndrome (EVC) is a rare disorder (the incidence is estimated at around 7/1,000,000) characterized by the clinical tetrad of chondrodystrophy, polydactyly, ectodermal dysplasia, and cardiac anomalies. Sagittal synostosis is characterized by a dolichocephalic head shape resulting from premature fusion of the sagittal suture. Both are rare disorders, which have never been reported together. We present a case of EVC and sagittal synostosis. We report the clinical features of a Hispanic boy with EVC and sagittal craniosynostosis who underwent cranial vault remodeling. The presentation of this patient is gone over in detail. A never before reported case of EVC and sagittal synostosis is presented in detail.

  19. 10. Whitney Arms Company, Van Slyck steel engraving, 1880 Photocopied ...

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

    10. Whitney Arms Company, Van Slyck steel engraving, 1880 Photocopied from Charles B. Norton, American Inventions and Improvements in Breech-Loading Small Arms (Springfield, Mass., 1880), p. 154 The engraving does not seem to have been included in the earlier 1872 edition. This is probably the single most widely copied view of the Whitney Arms Company works, and it is without doubt the most accurate. Compare with site plan, photo CT-2-13. - Eli Whitney Armory, West of Whitney Avenue, Armory Street Vicinity, Hamden, New Haven County, CT

  20. Baseline tests of the power-train electric delivery van

    NASA Technical Reports Server (NTRS)

    Lumannick, S.; Dustin, M. O.; Bozek, J. M.

    1977-01-01

    Vehicle maximum speed, range at constant speed, range over stop-and-go driving schedules, maximum acceleration, gradeability, gradeability limit, road energy consumption, road power, indicated energy consumption, braking capability, battery charger efficiency, and battery characteristics were determined for a modified utility van powered by sixteen 6-volt batteries connected in series. A chopper controller actuated by a foot accelerator pedal changes the voltage applied to the 22-kilowatt (30-hp) series-wound drive motor. In addition to the conventional hydraulic braking system, the vehicle has hydraulic regenerative braking. Cycle tests and acceleration tests were conducted with and without hydraulic regeneration.

  1. 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.

  2. Hybrid Meson Potentials and the Gluonic van der Waals Force

    SciTech Connect

    O. Lakhina; E.S. Swanson

    2004-03-01

    The chromoelectric polarizability of mesons governs the strength of the gluonic van der Waals force and therefore of non-quark-exchange processes in hadronic physics. We compute the polarizability of heavy mesons with the aid of lattice gauge theory and the Born--Oppenheimer adiabatic expansion. We find that the operator product expansion breaks down at surprisingly large quarks masses due to nonperturbative gluodynamics and that previous conclusions concerning J/{psi}--nuclear matter interactions and J/{psi} dissociation in the quark-gluon plasma must be substantially modified.

  3. [Van Heerden: the first female doctor in South Africa].

    PubMed

    Lammes, Frits B

    2013-01-01

    Petronella van Heerden (1887-1975) was born in South Africa. She studied medicine in Amsterdam from 1908 to 1915 and then worked as the first female doctor in her native country for 4 years before specialising in gynaecology in London. She then returned to Amsterdam, where she gained a PhD in 1923 on a thesis on endometriosis that was written in Afrikaans. She settled in Cape Town and participated in many political and emancipatory activities alongside her work as a doctor. She wrote two autobiographies. PMID:24103131

  4. 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. PMID:25846514

  5. A Novel Membrane Protein, VanJ, Conferring Resistance to Teicoplanin

    PubMed Central

    Novotna, Gabriela; Hill, Chris; Vincent, Karen; Liu, Chang

    2012-01-01

    Bacterial resistance to the glycopeptide antibiotic teicoplanin shows some important differences from the closely related compound vancomycin. They are currently poorly understood but may reflect significant differences in the mode of action of each antibiotic. Streptomyces coelicolor possesses a vanRSJKHAX gene cluster that when expressed confers resistance to both vancomycin and teicoplanin. The resistance to vancomycin is mediated by the enzymes encoded by vanKHAX, but not by vanJ. vanHAX effect a reprogramming of peptidoglycan biosynthesis, which is considered to be generic, conferring resistance to all glycopeptide antibiotics. Here, we show that vanKHAX are not in fact required for teicoplanin resistance in S. coelicolor, which instead is mediated solely by vanJ. vanJ is shown to encode a membrane protein oriented with its C-terminal active site exposed to the extracytoplasmic space. VanJ also confers resistance to the teicoplanin-like antibiotics ristocetin and A47934 and to a broad range of semisynthetic teicoplanin derivatives, but not generally to antibiotics or semisynthetic derivatives with vancomycin-like structures. vanJ homologues are found ubiquitously in streptomycetes and include staP from the Streptomyces toyocaensis A47934 biosynthetic gene cluster. While overexpression of staP also conferred resistance to teicoplanin, similar expression of other vanJ homologues (SCO2255, SCO7017, and SAV5946) did not. The vanJ and staP orthologues, therefore, appear to represent a subset of a larger protein family whose members have acquired specialist roles in antibiotic resistance. Future characterization of the divergent enzymatic activity within this new family will contribute to defining the molecular mechanisms important for teicoplanin activity and resistance. PMID:22232274

  6. The Biopesticide Paenibacillus popilliae Has a Vancomycin Resistance Gene Cluster Homologous to the Enterococcal VanA Vancomycin Resistance Gene Cluster

    PubMed Central

    Patel, Robin; Piper, Kerryl; Cockerill, Franklin R.; Steckelberg, James M.; Yousten, Allan A.

    2000-01-01

    We have previously identified, in Paenibacillus popilliae, a 708-bp sequence which has homology to the sequence of the enterococcal vanA gene. We have performed further studies revealing five genes encoding homologues of VanY, VanZ, VanH, VanA, and VanX in P. popilliae. The predicted amino acid sequences are similar to those in VanA vancomycin-resistant enterococci: 61% identity for VanY, 21% for VanZ, 74% for VanH, 77% for VanA, and 79% for VanX. The genes in P. popilliae may have been a precursor to or have had ancestral genes in common with vancomycin resistance genes in enterococci. The use of P. popilliae biopesticidal preparations in agricultural practice may have an impact on bacterial resistance in human pathogens. PMID:10681342

  7. Two-dimensional van der Waals C60 molecular crystal

    PubMed Central

    Reddy, C. D.; Gen Yu, Zhi; Zhang, Yong-Wei

    2015-01-01

    Two-dimensional (2D) atomic crystals, such as graphene and transition metal dichalcogenides et al. have drawn extraordinary attention recently. For these 2D materials, atoms within their monolayer are covalently bonded. An interesting question arises: Can molecules form a 2D monolayer crystal via van der Waals interactions? Here, we first study the structural stability of a free-standing infinite C60 molecular monolayer using molecular dynamic simulations, and find that the monolayer is stable up to 600 K. We further study the mechanical properties of the monolayer, and find that the elastic modulus, ultimate tensile stress and failure strain are 55–100 GPa, 90–155 MPa, and 1.5–2.3%, respectively, depending on the stretching orientation. The monolayer fails due to shearing and cavitation under uniaxial tensile loading. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the monolayer are found to be delocalized and as a result, the band gap is reduced to only 60% of the isolated C60 molecule. Interestingly, this band gap can be tuned up to ±30% using strain engineering. Owing to its thermal stability, low density, strain-tunable semi-conducting characteristics and large bending flexibility, this van der Waals molecular monolayer crystal presents aplenty opportunities for developing novel applications in nanoelectronics. PMID:26183501

  8. [Van Leeuwenhoek's discovery of bacteria: a look too far ahead].

    PubMed

    James, J

    2004-12-25

    During the 17th century microscopy was practised at the Royal Society in London by the curator Robert Hooke (1635-1703). He made use of the compound microscope (with uncorrected lenses) and published a book describing the most varied observations of botanical and animal specimens, among which he introduced the concept of 'cellula', observed in botanical material. The useful magnification was limited to 30-40 times. During the same period, the passionate amateur Anthonie van Leeuwenhoek in Delft (1632-1723) was engaged in microscopy, using a so-called simple microscope which was difficult to use but could be applied--albeit with a greater effort--at a much larger aperture so that magnifications in the range of 75-150 times were feasible. Using these self-made instruments, Van Leeuwenhoek was able to observe and describe bacteria, but this could not be confirmed at the Royal Society. It took 150 years before the compound microscope reached this level and bacteria were recognized as pathogenic organisms. PMID:15646862

  9. van der Waals forces influencing adhesion of cells

    PubMed Central

    Kendall, K.; Roberts, A. D.

    2015-01-01

    Adhesion molecules, often thought to be acting by a ‘lock and key’ mechanism, have been thought to control the adhesion of cells. While there is no doubt that a coating of adhesion molecules such as fibronectin on a surface affects cell adhesion, this paper aims to show that such surface contamination is only one factor in the equation. Starting from the baseline idea that van der Waals force is a ubiquitous attraction between all molecules, and thereby must contribute to cell adhesion, it is clear that effects from geometry, elasticity and surface molecules must all add on to the basic cell attractive force. These effects of geometry, elasticity and surface molecules are analysed. The adhesion force measured between macroscopic polymer spheres was found to be strongest when the surfaces were absolutely smooth and clean, with no projecting protruberances. Values of the measured surface energy were then about 35 mJ m−2, as expected for van der Waals attractions between the non-polar molecules. Surface projections such as abrasion roughness or dust reduced the molecular adhesion substantially. Water cut the measured surface energy to 3.4 mJ m−2. Surface active molecules lowered the adhesion still further to less than 0.3 mJ m−2. These observations do not support the lock and key concept. PMID:25533101

  10. Vincent van Gogh (1853-90): the plumbic artist.

    PubMed

    Weissman, Edward

    2008-05-01

    Following Vincent van Gogh's death in 1890, numerous physicians have offered diagnostic opinions regarding his still unverified illness. The discovery that he had ingested leaded oil paints prompted research that revealed his exposure to additional sources of lead and other toxic substances for 13 years before death. His complaints, derived from poignant letters to his brother, added compelling evidence that he had suffered neurotoxicity, encephalopathy and other consequences of lead. Vincent's suicide may have been precipitated by plumbism. Mankind has endured lead's presence for millennia, yet its destructive effects have been recognized sporadically. That symptoms of plumbism mimic other illnesses should prod a heightened index of suspicion. Had it not been for the financial and emotional support of Vincent by his brother, Theo, and the dedication of the latter's wife, Johanna, the artist's genius might never have been recognized. Widowed by the death of her husband six months after Vincent's demise, Johanna(1) remained the guardian of the painter's extraordinary artistic and literary output until critical acclaim established him as one of Europe's greatest artists. Her efforts, assisted by her son, in framing and exhibiting van Gogh's works, were crucial. She then translated and systematized his more than 750 letters to Theo, their sister, Willemien, their mother, fellow artists and others.(2).

  11. 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.

  12. Observations of Whistler-Mode Chorus with Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Kurth, William; Hospodarsky, George; Santolik, Ondrej; Kletzing, Craig; Bounds, Scott

    2014-10-01

    The Van Allen Probes mission provides an excellent opportunity to observe whistler-mode chorus and its role in the radiation belts. The plasma wave instrument on the two probes, called Waves, includes six identical waveform receivers covering the frequency range from 10 Hz to 12 kHz. The instrument measures three orthogonal magnetic field components and three orthogonal electric field components of waves. This complement supports wave-normal and Poynting flux analyses of chorus as well as other wave modes that interact with radiation belt particles. Extensive use of burst modes provides multicomponent waveforms enabling the study of individual chorus elements, including their substructure. The early-mission publications confirm the importance of chorus to the local acceleration of electrons in the outer radiation belts. The orbital precession of the twin Van Allen Probes through a complete range of local times now allows for a new survey of the distribution of chorus emissions. Hence, we now have the tools to study chorus from the nonlinear growth in chorus element substructures through synoptic studies of the near-equatorial occurrence of chorus out to a distance of approximately 5.8 Earth radii.

  13. 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)

  14. 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.

  15. [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. PMID:26202623

  16. Van der Waals Epitaxy of Ultrathin Halide Perovkistes

    NASA Astrophysics Data System (ADS)

    Wang, Yiping; Shi, Yunfeng; Shi, Jian

    We present our understanding, with CH3NH3PbX3 as a model system, on the 2D van der Waals growth and kinetics of 3D parent materials. We show the successful synthesis of ultrathin (sub-10 nm), large scale (a few tens of μm) single crystalline 2D perovskite thin films on layered mica substrate by van der Waals (VDW) epitaxy. Classical nucleation and growth model explaining conventional epitaxy has been modified to interpret the unique 2D results under VDW mechanism. The generalization of our model shows that a 3D crystal with low cohesive energy tends to favor the 2D growth while the one with strong cohesive energy has less kinetic window. With Monte Carlo simulations, we show that the fractal 2D morphology in perovskite precisely manifests the kinetic competition between VDW diffusivity and thermodynamic driving force, a unique phenomenon to VDW growth, suggesting a fundamental limit on the morphology stability of the 2D form of a 3D material. On the other hand, our single crystal thin film growth results and subsequent cryogenic study in the iodide perovskite provide a perfect resource for the exploration of its complex optical and electronic properties and unveiling the origins of its popularity in the energy conversion field.

  17. Landau, Case, van Kampen and Collisionless Fluid Closures

    NASA Astrophysics Data System (ADS)

    Joseph, Ilon

    2015-11-01

    Landau damping represents a fundamental paradox within plasma physics. The equations of motion of classical particles and fields are symmetric under time-reversal; yet, the open system formed by integration over velocity space is not invariant and damping results from phase-mixing. Here, it is shown that the Case-van Kampen theorem can be extended to magnetized plasmas: the linear eigenfunctions provide a complete representation of the particle distribution function and exponentially damped and growing eigenmodes must appear in pairs. The numerical Case-van Kampen transformation can performed efficiently in Fourier velocity space and allows fast timescales in the evolution of the system to be treated using exponential integration. On the other hand, fluid moments require integration over velocity space, and, thus, representation of Landau damping requires explicit introduction of the arrow of time through a collisionless damping operator. This operator captures linear phenomena at the cost of damping nonlinear phenomena such as the plasma echo. Numerical comparisons of these two rather different representations will be presented. LLNL-ABS-674917 prepared by LLNL under Contract DE-AC52-07NA27344.

  18. [Van Leeuwenhoek's discovery of bacteria: a look too far ahead].

    PubMed

    James, J

    2004-12-25

    During the 17th century microscopy was practised at the Royal Society in London by the curator Robert Hooke (1635-1703). He made use of the compound microscope (with uncorrected lenses) and published a book describing the most varied observations of botanical and animal specimens, among which he introduced the concept of 'cellula', observed in botanical material. The useful magnification was limited to 30-40 times. During the same period, the passionate amateur Anthonie van Leeuwenhoek in Delft (1632-1723) was engaged in microscopy, using a so-called simple microscope which was difficult to use but could be applied--albeit with a greater effort--at a much larger aperture so that magnifications in the range of 75-150 times were feasible. Using these self-made instruments, Van Leeuwenhoek was able to observe and describe bacteria, but this could not be confirmed at the Royal Society. It took 150 years before the compound microscope reached this level and bacteria were recognized as pathogenic organisms.

  19. Magnetic quantum phase transitions and entropy in Van Vleck magnet

    NASA Astrophysics Data System (ADS)

    Lavanov, G. Yu.; Kalita, V. M.; Ivanova, I. M.; Loktev, V. M.

    2016-10-01

    Field-induced magnetic quantum phase transitions in the Van Vleck paramagnet with easy-plane single-ion anisotropy and competing Ising exchange between ions with the spin S=1 have been studied theoretically. The description was made by minimizing the Lagrange function at zero temperature (T=0) and the free energy at T ≠ 0 . Stable and unstable solutions of equations corresponding to the case ψ0 = | 0 > asymptotically transform into those following from the Lagrange function at T=0. First-order phase transitions from the Van Vleck paramagnet state into the ferromagnet one were found to take place at a sufficiently high single-ion anisotropy. The entropy of such a magnet was shown to grow with its magnetization, as it occurs for antiferromagnets. At the point of quantum phase transition, the entropy has a jump, which magnitude depends on the ratio between the Ising exchange and anisotropy constants, as well as on the temperature. The described magnetic phase transition was supposed to be accompanied by the magnetocaloric effect. In the case when the Ising exchange dominates over the single-ion anisotropy, the magnetization reversal of ferromagnetic state by an external field was shown to be a phase transition of the first kind, which does not belong to orientational ones and which should be regarded as a quantum order-order phase transition.

  20. [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.

  1. Preserving the History of Wesleyan University's Van Vleck Observatory

    NASA Astrophysics Data System (ADS)

    Kilgard, Roy E.; Erickson, Paul; Herbst, William; Redfield, Seth; Williams, Amrys

    2016-01-01

    Since its opening in 1916, the Van Vleck Observatory at Wesleyan University has been dedicated to the joint mission of astronomical education and research. In celebration of the Observatory's centennial year, we are undertaking a number of projects to preserve and chronicle its history. The centerpiece of these efforts has been the renovation of the 20-inch Alvan Clark refracting telescope. Through careful compromise of historical restoration and modernization, we have ensured the future of one of the nation's last large, long-focus refractors well into the 21st century. In addition, we are producing an historical exhibition in the Observatory and online that will open to the public in the spring of 2016. Our exhibition explores the place-based nature of astronomical research, the scientific instruments, labor, and individuals that have connected places around the world in networks of observation, and the broader history of how observational astronomy has linked local people, amateur observers, professional astronomers, and the tools and objects that have facilitated their work under Connecticut's skies over the past 100 years. We are also collecting memories from the community to enrich our exhibition. If you have a story about the Van Vleck Observatory you would like to share with our researchers, please contact one of the authors.

  2. Determination of selected endocrine disrupting chemicals in Lake Van, Turkey.

    PubMed

    Oğuz, Ahmet R; Kankaya, Ertuğrul

    2013-09-01

    In the present study, we investigated the distribution of 17β-estradiol (E2), 17α-ethynylestradiol (EE2), alkylphenol ethoxylates (APEs) and organochlorine pesticides (DDE/DDT) in water and sediment samples in the Eastern Anatolia of Turkey, Lake Van, which is the largest soda lake in the world. The procedure consisted of solid phase extraction performed with OASIS HLB cartridges followed by non-competitive enzyme-linked immunosorbent assays (ELISA). The endocrine disrupting compounds E2, EE2, and DDT/DDE were detected in most of the lake samples with mean concentrations of 0.996 ± 0.304, 0.050 ± 0.022, and 0.749 ± 0.658 ng/L in water, respectively. Mean concentrations of E2, EE2 and DDT/DDE in sediment were 0.098 ± 0.053, 0.091 ± 0.072, and 1.281 ± 0.754 ng/g, respectively. APEs were not measured in the sediment samples. The EDCs levels in surface water and sediment samples were lower than that of other countries. The EDCs were also found in effluent and influent municipal sewage samples. Van city municipal wastewater treatment plant has no removal efficiency for EDCs. PMID:23771312

  3. 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

  4. 77 FR 54646 - Culturally Significant Objects Imported for Exhibition Determinations: “Becoming Van Gogh”

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-05

    ... Culturally Significant Objects Imported for Exhibition Determinations: ``Becoming Van Gogh'' SUMMARY: Notice... objects to be included in the exhibition ``Becoming Van Gogh,'' imported from abroad for temporary exhibition within the United States, are of cultural significance. The objects are imported pursuant to...

  5. 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 education,…

  6. 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…

  7. 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…

  8. 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... transfer of ownership or title, in their capacity as carriers of goods or as instruments of such carriers... to sale or other transfer from ownership in the United States to ownership abroad. If a vessel,...

  9. Synchronous regimes in ensembles of coupled Bonhoeffer-van der Pol oscillators.

    PubMed

    Kryukov, Alexey K; Osipov, Grigory V; Polovinkin, Andrey V; Kurths, Jürgen

    2009-04-01

    We study synchronous behavior in ensembles of locally coupled nonidentical Bonhoeffer-van der Pol oscillators. We show that, in a chain of N elements not less than 2;{N-1}, different coexisting regimes of global synchronization are possible, and we investigate wave-induced synchronous regimes in a chain and in a lattice of coupled nonidentical Bonhoeffer-van der Pol oscillators.

  10. 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 "other world"…

  11. 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 include:…

  12. 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 include:…

  13. MA-9 ASTRONAUT L. GORDON COOPER LEAVES TRANSFER VAN AT LAUNCH COMPLEX 14

    NASA Technical Reports Server (NTRS)

    1963-01-01

    MA-9 ASTRONAUT L. GORDON COOPER LEAVES TRANSFER VAN AT LAUNCH COMPLEX 14 S-63-6247 P-07136, ARCHIVE-03808 Astronaut L. Gordon Cooper, Jr., leaves the transfer van at Pad #14 for his ride up the gantry elevator to the 11th deck where he will be inserted into the spacecraft for his 22-orbit mission.

  14. 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 include:…

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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…

  1. Are Fast Interceptive Actions Continuously Guided by Vision? Revisiting Bootsma and van Wieringen (1990)

    ERIC Educational Resources Information Center

    van Soest, A. J.; Casius, L. J. R.; de Kok, W.; Krijger, M.; Meeder, M.; Beek, P. J.

    2010-01-01

    In an influential study, R. J. Bootsma and P. C. W. van Wieringen (1990) argued that 2 of their 5 participants used visual information continuously during the attacking forehand drive in table tennis, its brief duration vis-a-vis the visuomotor delay notwithstanding. The authors repeated Bootsma and van Wieringen's experiment and included a…

  2. 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…

  3. 76 FR 77299 - Culturally Significant Objects Imported for Exhibition Determinations: “Van Gogh. Up Close”

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Culturally Significant Objects Imported for Exhibition Determinations: ``Van Gogh. Up Close'' SUMMARY: Notice... objects to be included in the exhibition ``Van Gogh. Up Close.,'' imported from abroad for...

  4. The VanRS Homologous Two-Component System VnlRSAb of the Glycopeptide Producer Amycolatopsis balhimycina Activates Transcription of the vanHAXSc Genes in Streptomyces coelicolor, but not in A. balhimycina

    PubMed Central

    Kilian, Regina; Frasch, Hans-Joerg; Kulik, Andreas; Wohlleben, Wolfgang

    2016-01-01

    In enterococci and in Streptomyces coelicolor, a glycopeptide nonproducer, the glycopeptide resistance genes vanHAX are colocalized with vanRS. The two-component system (TCS) VanRS activates vanHAX transcription upon sensing the presence of glycopeptides. Amycolatopsis balhimycina, the producer of the vancomycin-like glycopeptide balhimycin, also possesses vanHAXAb genes. The genes for the VanRS-like TCS VnlRSAb, together with the carboxypeptidase gene vanYAb, are part of the balhimycin biosynthetic gene cluster, which is located 2 Mb separate from the vanHAXAb. The deletion of vnlRSAb did not affect glycopeptide resistance or balhimycin production. In the A. balhimycina vnlRAb deletion mutant, the vanHAXAb genes were expressed at the same level as in the wild type, and peptidoglycan (PG) analyses proved the synthesis of resistant PG precursors. Whereas vanHAXAb expression in A. balhimycina does not depend on VnlRAb, a VnlRAb-depending regulation of vanYAb was demonstrated by reverse transcriptase polymerase chain reaction (RT-PCR) and RNA-seq analyses. Although VnlRAb does not regulate the vanHAXAb genes in A. balhimycina, its heterologous expression in the glycopeptide-sensitive S. coelicolor ΔvanRSSc deletion mutant restored glycopeptide resistance. VnlRAb activates the vanHAXSc genes even in the absence of VanS. In addition, expression of vnlRAb increases actinorhodin production and influences morphological differentiation in S. coelicolor. PMID:27420548

  5. 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.

  6. 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

  7. Geomagnetic Storms and EMIC waves: Van Allen Probe observations

    NASA Astrophysics Data System (ADS)

    Wang, D.; Yuan, Z.; Yu, X.; Deng, X.; Zhou, M.; Huang, S.; Li, H.

    2015-12-01

    EMIC waves are believed to play an important role in the dynamics of ring current ions and radiation belt electrons, especially during geomagnetic storms. But, in which phase of the storm do the EMIC waves occur more is still under debate. Ground and some low altitude satellite observations demonstrate that EMIC waves are observed more frequently during the recovery phase, rather than during the main phase. Halford et al. 2010 looked at the occurrences of EMIC waves during 119 storms occurring throughout the CRRES mission. They found that 49 of the 119 (41%) storms observed EMIC waves and the majority, 56.25%, of storm time EMIC waves occurring during the main phase, while 35.57% in the recovery phase. One shortcoming of the CRRES mission is that the apogee of it did not covered the dawn to noon sector during its life time. Therefore, some dayside EMIC waves caused by the compression of magnetosphere may not be included in Halford et al 2010, as they mentioned. The apogee of Van Allen Probes covered all the MLT sectors from their launch to April 2014. Utilizing the data from magnetometer instrument on board the Van Allen Probe A, Wang et al. 2015 studied the occurrence rate of H-band and He-band EMIC waves in different MLT sectors, and Yu et al 2015 reported the O-band EMIC wave observations. In this work, we analysis the occurrence of EMIC waves during storms. According to the criteria of storm in Halford et al. 2010, we find 76 storms in our interested period, 8 September 2012 to 30 April 2014, when the apogee of Van Allen Probe A covered all the MLT sectors. To identify the onset of geomagnetic storm more accurately, we corrected the Sym-H index referred to Zhao and Zong (2011), which is helpful to demonstrate the activity of ring current. 50 of the 76 storms (66%) observed 124 EMIC wave events, in which 80 (64.5%) EMIC wave events are found in the recovery phase, more than the EMIC wave events in the main phase (35, 28.2%). The remaining 9 (7.3%) EMIC wave

  8. 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.

  9. Micro-Bubble Experiments at the Van de Graaff Accelerator

    SciTech Connect

    Sun, Z. J.; Wardle, Kent E.; Quigley, K. J.; Gromov, Roman; Youker, A. J.; Makarashvili, Vakhtang; Bailey, James; Stepinski, D. C.; Chemerisov, S. D.; Vandegrift, G. F.

    2015-02-01

    In order to test and verify the experimental designs at the linear accelerator (LINAC), several micro-scale bubble ("micro-bubble") experiments were conducted with the 3-MeV Van de Graaff (VDG) electron accelerator. The experimental setups included a square quartz tube, sodium bisulfate solution with different concentrations, cooling coils, gas chromatography (GC) system, raster magnets, and two high-resolution cameras that were controlled by a LabVIEW program. Different beam currents were applied in the VDG irradiation. Bubble generation (radiolysis), thermal expansion, thermal convection, and radiation damage were observed in the experiments. Photographs, videos, and gas formation (O2 + H2) data were collected. The micro-bubble experiments at VDG indicate that the design of the full-scale bubble experiments at the LINAC is reasonable.

  10. Characterization of rarefaction waves in van der Waals fluids.

    PubMed

    Yuen, Albert; Barnard, John J

    2015-12-01

    We calculate the isentropic evolution of an instantaneously heated foil, assuming a van der Waals equation of state with the Maxwell construction. The analysis by Yuen and Barnard [Phys. Rev. E 92, 033019 (2015)] is extended for the particular case of three degrees of freedom. We assume heating to temperatures in the vicinity of the critical point. The self-similar profiles of the rarefaction waves describing the evolution of the foil display plateaus in density and temperature due to a phase transition from the single-phase to the two-phase regime. The hydrodynamic equations are expressed in a dimensionless form and the solutions form a set of universal curves, depending on a single parameter: the dimensionless initial entropy. We characterize the rarefaction waves by calculating how the plateau length, density, pressure, temperature, velocity, internal energy, and sound speed vary with dimensionless initial entropy. PMID:26764692

  11. Ellis-van Creveld syndrome: a case report.

    PubMed

    Shah, B; Ashok, L; Sujatha, G P

    2008-01-01

    Ellis-van Creveld syndrome (EvC) is a disease complex, where all the three embryonic layers appear to be involved. This disorder is also called as Chondroectodermal dysplasia. EvC is an autosomal recessive disorder resulting from mutations in these patients. Mutations in the two genes EVC and EVC2, have been identified to cause the condition. It has been considered as a skeletal dysplasia with an incidence of approximately 1 out of 1,50,000 live births. A high prevalence has been reported among certain populations like Amish and Arabs of Gaza strip. There are more than 300 cases of EvC reported into the literature. About 50-60% of cases have been reported with congenital cardiac malformations. PMID:18974540

  12. Heterostructures based on inorganic and organic van der Waals systems

    SciTech Connect

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

    2014-09-01

    The two-dimensional limit of layered materials has recently been realized through the use of van der Waals (vdW) heterostructures composed of weakly interacting layers. In this paper, we describe two different classes of vdW heterostructures: inorganic vdW heterostructures prepared by co-lamination and restacking; and organic-inorganic hetero-epitaxy created by physical vapor deposition of organic molecule crystals on an inorganic vdW substrate. Both types of heterostructures exhibit atomically clean vdW interfaces. Employing such vdW heterostructures, we have demonstrated various novel devices, including graphene/hexagonal boron nitride (hBN) and MoS{sub 2} heterostructures for memory devices; graphene/MoS{sub 2}/WSe{sub 2}/graphene vertical p-n junctions for photovoltaic devices, and organic crystals on hBN with graphene electrodes for high-performance transistors.

  13. Ellis-van Creveld Syndrome: Mutations Uncovered in Lebanese Families.

    PubMed

    Valencia, Maria; Tabet, Lara; Yazbeck, Nadine; Araj, Alia; Ruiz-Perez, Victor L; Charaffedine, Khalil; Fares, Farah; Badra, Rebecca; Farra, Chantal

    2015-01-01

    Background. Ellis-van Creveld (EvC) syndrome is a rare, autosomal recessive disorder characterized by short stature, short limbs, growth retardation, polydactyly, and ectodermal defects with cardiac anomalies occurring in around 60% of cases. EVC syndrome has been linked to mutations in EVC and EVC2 genes. Case Presentation. We report EvC syndrome in two unrelated Lebanese families both having homozygous mutations in the EVC2 gene, c.2653C>T (p.(Arg885(*))) and c.2012_2015del (p.(Leu671(*))) in exons 15 and 13, respectively, with the latter being reported for the first time. Conclusion. Although EvC has been largely described in the medical literature, clinical features of this syndrome vary. While more research is required to explore other genes involved in EvC, early diagnosis and therapeutic care are important to achieve a better quality of life.

  14. Ellis-van Creveld syndrome: a case report.

    PubMed

    Shah, B; Ashok, L; Sujatha, G P

    2008-01-01

    Ellis-van Creveld syndrome (EvC) is a disease complex, where all the three embryonic layers appear to be involved. This disorder is also called as Chondroectodermal dysplasia. EvC is an autosomal recessive disorder resulting from mutations in these patients. Mutations in the two genes EVC and EVC2, have been identified to cause the condition. It has been considered as a skeletal dysplasia with an incidence of approximately 1 out of 1,50,000 live births. A high prevalence has been reported among certain populations like Amish and Arabs of Gaza strip. There are more than 300 cases of EvC reported into the literature. About 50-60% of cases have been reported with congenital cardiac malformations.

  15. A crossover in anisotropic nanomechanochemistry of van der Waals crystals

    NASA Astrophysics Data System (ADS)

    Shimamura, Kohei; Misawa, Masaaki; Li, Ying; Kalia, Rajiv K.; Nakano, Aiichiro; Shimojo, Fuyuki; Vashishta, Priya

    2015-12-01

    In nanoscale mechanochemistry, mechanical forces selectively break covalent bonds to essentially control chemical reactions. An archetype is anisotropic detonation of layered energetic molecular crystals bonded by van der Waals (vdW) interactions. Here, quantum molecular dynamics simulations reveal a crossover of anisotropic nanomechanochemistry of vdW crystal. Within 10-13 s from the passage of shock front, lateral collision produces NO2 via twisting and bending of nitro-groups and the resulting inverse Jahn-Teller effect, which is mediated by strong intra-layer hydrogen bonds. Subsequently, as we transition from heterogeneous to homogeneous mechanochemical regimes around 10-12 s, shock normal to multilayers becomes more reactive, producing H2O assisted by inter-layer N-N bond formation. These time-resolved results provide much needed atomistic understanding of nanomechanochemistry that underlies a wider range of technologies.

  16. Dynamics of a delayed van der Pol-Mathieu oscillator

    NASA Astrophysics Data System (ADS)

    Sarmah, Dipak; Bora, Madhurjya P.

    2014-02-01

    The dynamics of a van der Pol-Mathieu (vdPM) equation with time delay is considered. The vdPM model can be realized as the governing equation for dust density in a simplified model of dusty plasma. The dynamics of the time-delayed equation is analyzed by separating the time-scales of the system assuming that the fundamental simple harmonic oscillator is at least an ϐ(ɛ) dominating other terms of the oscillator including time-delay, where ɛ ≪ 1. Our analytic prediction of the slow-flow system correctly represents the dynamics of the original system, showing periodic creation and annihilation of multi-periodic limit cycles. The original system is then analyzed using the DDE-Biftool [1] bifurcation analysis tool. We show that for large time-delay, the system undergoes a double-Hopf bifurcation, whereas for small delay, it undergoes a Bogdanov-Takens bifurcation.

  17. Extended van Hove singularity and superconducting instability in doped graphene.

    PubMed

    McChesney, J L; Bostwick, Aaron; Ohta, Taisuke; Seyller, Thomas; Horn, Karsten; González, J; Rotenberg, Eli

    2010-04-01

    We have investigated the effects of doping on a single layer of graphene using angle-resolved photoemission spectroscopy. We show that many-body interactions severely warp the Fermi surface, leading to an extended van Hove singularity (EVHS) at the graphene M point. The ground state properties of graphene with such an EVHS are calculated, analyzing the competition between a magnetic instability and the tendency towards superconductivity. We find that the latter plays the dominant role as it is enhanced by the strong modulation of the interaction along the Fermi line, leading to an energy scale for the onset of the pairing instability as large as 1 meV when the Fermi energy is sufficiently close to the EVHS. PMID:20481902

  18. Ion spectral structures observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Ferradas, C.; Zhang, J.; Spence, H. E.; Kistler, L. M.; Larsen, B.; Reeves, G. D.; Skoug, R. M.; Funsten, H. O.

    2015-12-01

    During the last decades several missions have recorded the presence of dynamic spectral features of energetic ions in the inner magnetosphere. Previous studies have reported single "nose-like" structures occurring alone and simultaneous nose-like structures (up to three). These ion structures are named after the characteristic shapes of energy bands or gaps in the energy-time spectrograms of in situ measured ion fluxes. They constitute the observational signatures of ion acceleration, transport, and loss in the global magnetosphere. The HOPE mass spectrometer onboard the Van Allen Probes measures energetic hydrogen, helium, and oxygen ions near the inner edge of the plasma sheet, where these ion structures are observed. We present a statistical study of nose-like structures, using 2-years measurements from the HOPE instrument. The results provide important details about the spatial distribution (dependence on geocentric distance), spectral features of the structures (differences among species), and geomagnetic conditions under which these structures occur.

  19. A crossover in anisotropic nanomechanochemistry of van der Waals crystals

    SciTech Connect

    Shimamura, Kohei; Misawa, Masaaki; Li, Ying; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya; Shimojo, Fuyuki

    2015-12-07

    In nanoscale mechanochemistry, mechanical forces selectively break covalent bonds to essentially control chemical reactions. An archetype is anisotropic detonation of layered energetic molecular crystals bonded by van der Waals (vdW) interactions. Here, quantum molecular dynamics simulations reveal a crossover of anisotropic nanomechanochemistry of vdW crystal. Within 10{sup −13} s from the passage of shock front, lateral collision produces NO{sub 2} via twisting and bending of nitro-groups and the resulting inverse Jahn-Teller effect, which is mediated by strong intra-layer hydrogen bonds. Subsequently, as we transition from heterogeneous to homogeneous mechanochemical regimes around 10{sup −12} s, shock normal to multilayers becomes more reactive, producing H{sub 2}O assisted by inter-layer N-N bond formation. These time-resolved results provide much needed atomistic understanding of nanomechanochemistry that underlies a wider range of technologies.

  20. Van der Waals Density Functional Theory with Applications

    NASA Astrophysics Data System (ADS)

    Langreth, David C.

    2004-03-01

    We discuss the development of electronic density functionals that are applicable for weakly bound systems where the van der Waals interaction and its ramifications become important. Our current functionals approach the correct asymptotic dependence at large distances and are seamless at small distances. The first form of the functional, appropriate for layered systems, has been recently applied to graphite, boron nitride, and molybdenum sulfide [H. Rydberg et al., Phys. Rev. Lett. 91, 126402 (2003) and D. C. Langreth, Int. J. Quant. Chem. (submitted), see http//:www.physics.rutgers.edu/ ˜langreth/preprints/dft2003.pdf]. The second form of the functional [M. Dion it et al. (to be published)] is appropriate for arbitrary geometries. Recent results on rare gas dimers and the benzene dimer suggest promise for this method as well.

  1. Van der Waals Interactions in Density Functional Theory: Intermolecular Complexes

    NASA Astrophysics Data System (ADS)

    Kannemann, Felix; Becke, Axel

    2010-03-01

    Conventional density functional theory (GGA and hybrid functionals) fails to account for dispersion interactions and is therefore not applicable to systems where van der Waals interactions play a dominant role, such as intermolecular complexes and biomolecules. The exchange-hole dipole moment (XDM) dispersion model of Becke and Johnson [A. D. Becke and E. R. Johnson, J. Chem. Phys. 127, 154108 (2007)] corrects for this deficiency. We have previously shown that the XDM dispersion model can be combined with standard GGA functionals (PW86 for exchange and PBE for correlation) to give accurate binding energy curves for rare-gas diatomics [F. O. Kannemann and A. D. Becke, J. Chem. Theory Comput. 5, 719 (2009)]. Here we present further tests of the GGA-XDM method using benchmark sets including hydrogen bonding, electrostatic, dispersion and stacking interactions, and systems ranging from rare-gas diatomics to biomolecular complexes.

  2. Van Allen Probe Charging During the St. Patrick's Day Event

    NASA Technical Reports Server (NTRS)

    Parker, L. Neergaard; Minow, J. I.

    2015-01-01

    The geomagnetic storms on and around March 17, 2015 marked the largest storms seen in the declining phase of the solar cycle to date. We use the Helium Oxygen Proton Electron (HOPE) mass spectrometer on board the Van Allen Probe - A and B satellites to study in detail the charging effects seen on these spacecraft during this time. Ion particle flux data provides information on the magnitude of the charging events using the ion line charging signature due to low energy ions accelerated by the spacecraft potential. Electron flux observations are used to correlate the charging environment with variations in spacecraft potential through the event. We also investigate the density and temperature of ions and electrons during the time of the charging event.

  3. Characterization of rarefaction waves in van der Waals fluids

    NASA Astrophysics Data System (ADS)

    Yuen, Albert; Barnard, John J.

    2015-12-01

    We calculate the isentropic evolution of an instantaneously heated foil, assuming a van der Waals equation of state with the Maxwell construction. The analysis by Yuen and Barnard [Phys. Rev. E 92, 033019 (2015), 10.1103/PhysRevE.92.033019] is extended for the particular case of three degrees of freedom. We assume heating to temperatures in the vicinity of the critical point. The self-similar profiles of the rarefaction waves describing the evolution of the foil display plateaus in density and temperature due to a phase transition from the single-phase to the two-phase regime. The hydrodynamic equations are expressed in a dimensionless form and the solutions form a set of universal curves, depending on a single parameter: the dimensionless initial entropy. We characterize the rarefaction waves by calculating how the plateau length, density, pressure, temperature, velocity, internal energy, and sound speed vary with dimensionless initial entropy.

  4. [Determination of parasite fauna of chicken in the Van region].

    PubMed

    Orunç, Ozlem; Biçek, Kamile

    2009-01-01

    The aim of this study was to determine the parasite fauna of the chicken in Van Province in 2002 and 2003. The material of the present study included endoparasites and ectoparasites determined by rutine parasitological examinations. Direct, flotation and sedimentation techniques for endoparasites were used. The total of endoparasites and ectoparasites were determined as 85% and 76% respectively. The ratios of endoparasites obtained from the chicken were coccidial oocystis 65%, Echinostoma spp. 2%, Davania proglottina 8%, Raillietina spp. 10%, Trichostrongylus tenuis 4%, Dispharynx nasuta 1%, Ascaridia galli 13%, Heterakis gallinarum 15%, Capillaria spp. 30% whereas ratios of ectoparasites were Goniocotes hologaster 32%, Lipeurus heteragraphus 6%, Eomenacanthus stramineus 42%, Menacanthus cornutus 11%, Menopon gallinae 22%.

  5. Characterization of rarefaction waves in van der Waals fluids.

    PubMed

    Yuen, Albert; Barnard, John J

    2015-12-01

    We calculate the isentropic evolution of an instantaneously heated foil, assuming a van der Waals equation of state with the Maxwell construction. The analysis by Yuen and Barnard [Phys. Rev. E 92, 033019 (2015)] is extended for the particular case of three degrees of freedom. We assume heating to temperatures in the vicinity of the critical point. The self-similar profiles of the rarefaction waves describing the evolution of the foil display plateaus in density and temperature due to a phase transition from the single-phase to the two-phase regime. The hydrodynamic equations are expressed in a dimensionless form and the solutions form a set of universal curves, depending on a single parameter: the dimensionless initial entropy. We characterize the rarefaction waves by calculating how the plateau length, density, pressure, temperature, velocity, internal energy, and sound speed vary with dimensionless initial entropy.

  6. [Intestinal parasitoses detected in primary schoolchildren in the Van province].

    PubMed

    Taş Cengiz, Zeynep; Akbayram, Sinan; Ciçek, Mutalip; Yilmaz, Hasan

    2009-01-01

    This study was carried out on school children in primary schools in the Van province in order to investigate the distribution of intestinal parasitoses. The study was conducted in 7-15 year-old primary schoolchildren during the years from 2003-2005. Stool specimens were taken from 2975 school children; of these, 1289 were female and 1686, male. The specimens were examined by native-Lugol, flotation and trichrome staining methods in the parasitology laboratory of the Health Research and Training Hospital, Yüzüncü Yil University. One or more parasite species were detected in 1916 (64.4%) stool specimens of 2975 children. Parasitosis was detected in 65.7% of females and in 63.4% of males. Blastocystis hominis, Giardia intestinalis, Entamoeba coli, Iodamoeba butschlii, Chilomastix mesnili, Endolimax nana, Entamoeba histolytica/Entamoeba dispar, Entamoeba hartmanni, Enteromonas hominis, Retortamonas intestinalis, Dientamoeba fragilis, Trichomonas hominis, Ascaris lumbricoides, Hymenolepis nana, Trichuris trichiura, Enterobius vermicularis and Fasciola hepatica were detected in 27.4%, 16.4%, 14.9%, 3.9%, 2.9%, 1.8%, 1.1%, 0.6%, 0.5%, 0.5%, 0.4%, 0.2%, 7.5%, 5.3%, 0.7%, 0.6% and 0.03% of the specimens, respectively. In conclusion, there are still high rates of intestinal parasitoses in school children in this region because care is not taken in hygiene and the socioeconomic status is low in the Van province. PMID:20101580

  7. The 2011 Mw 7.1 Van (Eastern Turkey) earthquake

    USGS Publications Warehouse

    Elliot, John R.; Copley, Alex C.; Holley, R.; Scharer, Katherine M.; Parsons, Barry

    2013-01-01

    We use interferometric synthetic aperture radar (InSAR), body wave seismology, satellite imagery, and field observations to constrain the fault parameters of the Mw 7.1 2011 Van (Eastern Turkey) reverse-slip earthquake, in the Turkish-Iranian plateau. Distributed slip models from elastic dislocation modeling of the InSAR surface displacements from ENVISAT and COSMO-SkyMed interferograms indicate up to 9 m of reverse and oblique slip on a pair of en echelon NW 40 °–54 ° dipping fault planes which have surface extensions projecting to just 10 km north of the city of Van. The slip remained buried and is relatively deep, with a centroid depth of 14 km, and the rupture reaching only within 8–9 km of the surface, consistent with the lack of significant ground rupture. The up-dip extension of this modeled WSW striking fault plane coincides with field observations of weak ground deformation seen on the western of the two fault segments and has a dip consistent with that seen at the surface in fault gouge exposed in Quaternary sediments. No significant coseismic slip is found in the upper 8 km of the crust above the main slip patches, except for a small region on the eastern segment potentially resulting from the Mw 5.9 aftershock on the same day. We perform extensive resolution tests on the data to confirm the robustness of the observed slip deficit in the shallow crust. We resolve a steep gradient in displacement at the point where the planes of the two fault segments ends are inferred to abut at depth, possibly exerting some structural control on rupture extent.

  8. vanA in Enterococcus faecium, Enterococcus faecalis, and Enterococcus casseliflavus detected in French cattle.

    PubMed

    Haenni, Marisa; Saras, Estelle; Châtre, Pierre; Meunier, Danièle; Martin, Sylvie; Lepage, Gérard; Ménard, Marie-Françoise; Lebreton, Patricia; Rambaud, Thomas; Madec, Jean-Yves

    2009-11-01

    The goal of this study was to assess the presence of enterococci species presenting van-mediated glycopeptide resistance in French cattle. Fecal samples were collected from healthy and sick animals, and enterococci were screened for vancomycin resistance. Vancomycin resistance was principally encountered in Enterococcus gallinarum and Enterococcus casseliflavus strains. However, glycopeptide resistance was detected in three different species of enterococci (E. faecalis, E. faecium, and E. casseliflavus). Molecular characterization of the genetic support proved that they all presented the prototypic VanA element. Interestingly, the E. casseliflavus strain displayed a remarkable VanB phenotype/vanA-vanC genotype. Transferability, associated resistances, and factors of vanA cotransfer were sought. This study proved that acquired vanA genes can still be detected in food-producing animals more than a decade after the avoparcin ban. Indeed, calves, which are recurrently exposed to antibiotics in France, may allow the re-emergence of glycopeptide resistance through coselection factors, and this might potentially be concerning for human health. PMID:19694552

  9. Thirty-Six Month Evaluation of UPS Diesel Hybrid-Electric Delivery Vans

    SciTech Connect

    Lammert, M.; Walkowicz, K.

    2012-03-01

    This evaluation compared six hybrids and six standard diesels in UPS facilities in Phoenix, Arizona. Dispatch and maintenance practices are the same at both facilities. GPS logging, fueling, and maintenance records are used to evaluate the performance of these step delivery vans. The hybrids' average monthly mileage rate was 18% less than the diesel vans. The hybrids consistently were driven a fewer number of miles throughout the evaluation period. The hybrids idled more and operating at slower speeds than the diesels, and the diesels spent slightly more time operating at greater speeds, accounting for much of the hybrids fewer monthly miles. The average fuel economy for the hybrid vans is 13.0 mpg, 23% greater than the diesel vans 10.6 mpg. Total hybrid maintenance cost/mile of $0.141 was 9% more than the $0.130 for the diesel vans. Propulsion-related maintenance cost/mile of $0.037 for the hybrid vans was 25% more than the $0.029 for the diesel vans. Neither difference was found to be statistically significant. The hybrid group had a cumulative average of 96.3% uptime, less than the diesel group's 99.0% uptime. The hybrids experienced troubleshooting and recalibration issues related to prototype components that were primarily responsible for the lower uptime figures.

  10. Ontogenic Caste Differences in the Van der Vecht Organ of Primitively Eusocial Neotropical Paper Wasps

    PubMed Central

    de Souza, André Rodrigues; Petrocelli, Iacopo; Lino-Neto, José; Santos, Eduardo Fernando; Noll, Fernando Barbosa; Turillazzi, Stefano

    2016-01-01

    Recent studies have reported incipient morphological caste dimorphism in the Van der Vecht organ size of some temperate Polistes paper wasps. Whether species other than the temperate ones show a similar pattern remains elusive. Here, we have studied some Neotropical Polistes species. By comparing females collected through the year, we showed caste related differences in the size of the Van der Vecht organ in P. ferreri (body size corrected Van der Vech organ size of queens = 0.45 ± 0.06, workers = 0.38 ± 0.07 mm2, p = 0.0021), P. versicolor (body size corrected Van der Vech organ size of queens = 0.54 ± 0.11, workers = 0.46 ± 0.09 mm2, p = 0.010), but not P. simillimus (body size corrected Van der Vech organ size of queens = 0.52 ± 0.05, workers = 0.49 ± 0.06 mm2, p = 0.238). Therefore, it seems that queens and workers of some Neotropical Polistes have diverged in their ontogenic trajectory of the Van der Vecht organ size, providing clear evidence for incipient morphological caste dimorphism. As Polistes are distributed mostly in the tropics, we propose that physical caste differences may be widespread in the genus. Also, we highlight that morphological divergence in the queen–worker phenotypes may have started through differential selection of body structures, like the Van der Vecht organ. PMID:27167514

  11. Ontogenic Caste Differences in the Van der Vecht Organ of Primitively Eusocial Neotropical Paper Wasps.

    PubMed

    de Souza, André Rodrigues; Petrocelli, Iacopo; Lino-Neto, José; Santos, Eduardo Fernando; Noll, Fernando Barbosa; Turillazzi, Stefano

    2016-01-01

    Recent studies have reported incipient morphological caste dimorphism in the Van der Vecht organ size of some temperate Polistes paper wasps. Whether species other than the temperate ones show a similar pattern remains elusive. Here, we have studied some Neotropical Polistes species. By comparing females collected through the year, we showed caste related differences in the size of the Van der Vecht organ in P. ferreri (body size corrected Van der Vech organ size of queens = 0.45 ± 0.06, workers = 0.38 ± 0.07 mm2, p = 0.0021), P. versicolor (body size corrected Van der Vech organ size of queens = 0.54 ± 0.11, workers = 0.46 ± 0.09 mm2, p = 0.010), but not P. simillimus (body size corrected Van der Vech organ size of queens = 0.52 ± 0.05, workers = 0.49 ± 0.06 mm2, p = 0.238). Therefore, it seems that queens and workers of some Neotropical Polistes have diverged in their ontogenic trajectory of the Van der Vecht organ size, providing clear evidence for incipient morphological caste dimorphism. As Polistes are distributed mostly in the tropics, we propose that physical caste differences may be widespread in the genus. Also, we highlight that morphological divergence in the queen-worker phenotypes may have started through differential selection of body structures, like the Van der Vecht organ. PMID:27167514

  12. 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 of 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.

  13. Cell permeable vanX inhibitors as vancomycin re-sensitizing agents.

    PubMed

    Muthyala, Ramaiah; Rastogi, Namrata; Shin, Woo Shik; Peterson, Marnie L; Sham, Yuk Yin

    2014-06-01

    VanX is an induced zinc metallo d-Ala-d-Ala dipeptidase involved in the viable remodeling of bacterial cell wall that is essential for the development of VREF. Here we report two cyclic thiohydroxamic acid-based peptide analogs that were designed, synthesized and investigated as vancomycin re-sensitizing agents. These compounds exhibit low micromolar inhibitory activity against vanX, with low cytotoxicity and were shown to increase vancomycin sensitivity against VREF. The improved pharmacological properties of these novel inhibitors over previous transition state mimics should provide an enhanced platform for designing potent vanX inhibitors for overcoming vancomycin resistance. PMID:24751446

  14. Tuning the van der Waals Interaction of Graphene with Molecules via Doping

    NASA Astrophysics Data System (ADS)

    Huttmann, Felix; Martínez-Galera, Antonio J.; Caciuc, Vasile; Atodiresei, Nicolae; Schumacher, Stefan; Standop, Sebastian; Hamada, Ikutaro; Wehling, Tim O.; Blügel, Stefan; Michely, Thomas

    2015-12-01

    We use scanning tunneling microscopy to visualize and thermal desorption spectroscopy to quantitatively measure that the binding of naphthalene molecules to graphene, a case of pure van der Waals interaction, strengthens with n and weakens with p doping of graphene. Density-functional theory calculations that include the van der Waals interaction in a seamless, ab initio way accurately reproduce the observed trend in binding energies. Based on a model calculation, we propose that the van der Waals interaction is modified by changing the spatial extent of graphene's π orbitals via doping.

  15. Orion GNC Mitigation Efforts for Van Allen Radiation

    NASA Technical Reports Server (NTRS)

    King, Ellis T.; Jackson, Mark

    2013-01-01

    The Orion Crew Module (CM) is NASA's next generation manned space vehicle, scheduled to return humans to lunar orbit in the coming decade. The Orion avionics and GN&C architectures have progressed through a number of project phases and are nearing completion of a major milestone. The first unmanned test mission, dubbed "Exploration Flight Test One" (EFT-1) is scheduled to launch from NASA Kennedy Space Center late next year and provides the first integrated test of all the vehicle systems, avionics and software. The EFT-1 mission will be an unmanned test flight that includes a high speed re-entry from an elliptical orbit, which will be launched on an expendable launch vehicle (ELV). The ELV will place CM and the ELV upper stage into a low Earth orbit (LEO) for one revolution. After the first LEO, the ELV upper stage will re-ignite and place the combined upper stage/CM into an elliptical orbit whose perigee results in a high energy entry to test CM response in a relatively high velocity, high heating environment. While not producing entry velocities as high as those experienced in returning from a lunar orbit, the trajectory was chosen to provide higher stresses on the thermal protection and guided entry systems, as compared against a lower energy LEO entry. However the required entry geometry with constraints on inclination and landing site result in a trajectory that lingers for many hours in the Van Allen radiation belts. This exposes the vehicle and avionics to much higher levels of high energy proton radiation than a typical LEO or lunar trajectory would encounter. As a result, Van Allen radiation poses a significant risk to the Orion avionics system, and particularly the Flight Control Module (FCM) computers that house the GN&C flight software. The measures taken by the Orion GN&C, Flight Software and Avionics teams to mitigate the risks associated with the Van Allen radiation on EFT-1 are covered in the paper. Background on the Orion avionics subsystem is

  16. Van earthquakes (23 October 2011 and 9 November 2011) and performance of masonry and adobe structures

    NASA Astrophysics Data System (ADS)

    Güney, D.

    2012-11-01

    Earthquakes, which are unavoidable natural phenomena in Turkey, have often produced economic and social disaster. The latest destructive earthquakes happened in Van city. Van, Turkey, earthquakes with M = 7.2 occurred on 23 October 2011 at 13:41 (local time), whose epicenter was about 16 km north of Van (Tabanlı village) and M = 5.6 on 9 November 2011 epicentered near the town of Edremit south of Van in eastern Turkey and caused the loss of life and heavy damages. Both earthquakes killed 644 people and 2608 people were injured. Approximately 4000 buildings collapsed or were seriously damaged. The majority of the damaged structures were seismically insufficient, unreinforced masonry and adobe buildings in rural areas. In this paper, site surveys of the damaged masonry and adobe buildings are presented and the reasons for the caused damages are discussed in detail.

  17. Evaluating a Test of van Hiele Levels: A Response to Crowley and Wilson.

    ERIC Educational Resources Information Center

    Usiskin, Zalman; Senk, Sharon

    1990-01-01

    Responds to Crowley's and Wilson's articles on the reliability of the van Hiele Geometry Test. Discusses the issue of the difficulty of trying to maximize content validity while minimizing measurement error. (YP)

  18. van der Waals rovibration levels and the high resolution spectrum of the argon-benzene dimer

    NASA Astrophysics Data System (ADS)

    van der Avoird, Ad

    1993-04-01

    The van der Waals vibrations of Ar-benzene are calculated from two different intermolecular potentials, which are analytic fits to the same ab initio potential. The rovibrational Hamiltonian was derived earlier; the wave functions of the large amplitude vibrations are expanded in products of harmonic oscillator functions. The rotational structure of each van der Waals state is obtained from perturbation theory, as well as from variational calculations of the complete rovibrational states for J=0, 1, and 2. The degenerate bending modes and combinations have a large vibrational angular momentum; for their rotational structure it is important to include all first, second, and higher order rovibrational (Coriolis) coupling. The calculated vibrational frequencies, the information about rovibrational coupling, and the PI(C6v) selection rules for van der Waals transitions, in combination with the vibronic 601 transition on the benzene monomer, lead to a partially new assignment of the three van der Waals sidebands observed in high resolution UV spectra.

  19. Van Hove singularities of some icosahedral boron-rich solids by differential reflectivity spectra

    NASA Astrophysics Data System (ADS)

    Werheit, Helmut

    2015-09-01

    Differential reflectivity spectra of some icosahedral boron rich solids, β-rhombohedral boron, boron carbide and YB66-type crystals, were measured. The derivatives yield the van Hove singularities, which are compared with results obtained by other experimental methods.

  20. Quantitative determination of van Gogh's painting grounds using SEM/EDX.

    PubMed

    Haswell, Ralph; Carlyle, Leslie; Mensch, Kees T J

    2011-10-01

    We have investigated the potential of utilizing analytical electron microscopy to quantitatively examine the grounds used by van Gogh and, in particular, the absolute amount of extender employed. To determine the accuracy that can be achieved, a series of oil paint reconstructions were used as standards. The proportion of extender was measured using scanning electron microscopy and energy dispersive X-ray spectroscopy, and a relative error of 10% or better was achieved. The same method was then used to determine the ground composition of real samples from van Gogh paintings. The results obtained in this work are part of a more quantitative method of comparing and classifying paint cross sections, which will supplement the more traditional qualitative approach. The information obtained from this study is being used to add to our knowledge of the methods and materials used by van Gogh, which is helping in the reconstruction of van Gogh's oeuvre and attribution. PMID:21144113

  1. 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)

  2. Detection of vanA and vanB2-containing enterococci from food samples in Spain, including Enterococcus faecium strains of CC17 and the new singleton ST425.

    PubMed

    López, María; Sáenz, Yolanda; Rojo-Bezares, Beatriz; Martínez, Santiago; del Campo, Rosa; Ruiz-Larrea, Fernanda; Zarazaga, Myriam; Torres, Carmen

    2009-07-31

    Two-hundred-twenty-nine food samples of animal origin were tested to know the prevalence of vancomycin-resistant enterococci (VRE) after a decade of avoparcin ban as animal growth promoter in Spain. VRE with acquired mechanism of resistance were detected in 9 of these 229 samples (3.9%, obtained from chicken, veal and rabbit), and one VRE per food sample was further characterized. The vanA gene was identified in seven isolates (2 E. faecium, 3 E. durans, and 2 E. hirae), and the vanB2 gene in the remaining 2 isolates (identified as E. faecium). The two vanB2 isolates showed a phenotype of multiresistance that included, in addition to vancomycin, also ampicillin, erythromycin, tetracycline, streptomycin, kanamycin, ciprofloxacin, chloramphenicol and trimethoprim-sulfamethoxazole and contained, among others, erm(B), tet(M), ant(6), and aph(3')-III genes. Most of vanA enterococci showed erythromycin and tetracycline resistance and contained the erm(B) and tet(M) genes. One vanA- and both vanB2-positive E. faecium isolates were classified by MLST analysis into the CC17 clonal complex (ST17 and ST78), and one additional vanA isolate was included in a new sequence type named ST425 (singleton). Co-transference by conjugation of erm(B) and vanA genes was demonstrated in one vanA-positive E. faecium isolate. The inclusion of vanB2 cluster into Tn5382 structure was demonstrated in the two vanB2 isolates, as well as the linkage pbp5-Tn5382, and beta-haemolysis and gelatinase production was identified in one of them. Food sample of animal origin could be a vehicle of transference of VRE of vanA and vanB2 type that could be transferred to humans. PMID:19493581

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

    DOE PAGESBeta

    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 wasmore » 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 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 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.« less

  4. New orbits for comets C/1843 J1 (Mauvais) and C/1853 W1 (van Arsdale)

    NASA Astrophysics Data System (ADS)

    Branham, R. L., Jr.

    2015-12-01

    New orbits for comet C/1843 J1 (Mauvais) and comet C/1853 W1 (van Arsdale) are calculated. Both orbits are hyperbolic, with e=1.001145 and semi-major axis a= -1412.18 AU for Mauvais and e=1.000700 and a= -2919.24 AU for van Arsdale. Integrating the orbits backwards indicate that both comets were born in the far Oort cloud.

  5. High Rates of Fecal Carriage of Nonenterococcal vanB in both Children and Adults▿

    PubMed Central

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

    2008-01-01

    We examined the rate of fecal carriage of vanB in the absence of cultivable vancomycin-resistant enterococci in three distinct populations (children, community adults, and hemodialysis patients). Nonenterococcal vanB carriage was similarly high in hemodialysis patients (45%) and community adults (63%; P = 0.066) and significantly more common among community adults than children (27%; P = 0.001). PMID:18180361

  6. 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.

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

    SciTech Connect

    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 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 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.

  8. Probable identity of Goltz syndrome and Van Allen-Myhre syndrome: evidence from phenotypic evolution.

    PubMed

    Hancock, Susan; Pryde, Peter; Fong, Christine; Brazy, Jane E; Stewart, Katharina; Favour, Amy; Pauli, Richard M

    2002-07-15

    We describe a girl who was diagnosed with split foot-split hand anomaly prenatally, in whom at birth the diagnosis of Van Allen-Myhre syndrome was made, and who at 8 months of age was recognized to have Goltz syndrome. Based on the evolution of clinical features in this infant, we suggest that our case, as well as that reported by Van Allen and Myhre, is an example of unusually severe Goltz syndrome.

  9. 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

  10. Consistent van der Waals radii for the whole main group.

    PubMed

    Mantina, Manjeera; Chamberlin, Adam C; Valero, Rosendo; Cramer, Christopher J; Truhlar, Donald G

    2009-05-14

    Atomic radii are not precisely defined but are nevertheless widely used parameters in modeling and understanding molecular structure and interactions. The van der Waals radii determined by Bondi from molecular crystals and data for gases are the most widely used values, but Bondi recommended radius values for only 28 of the 44 main-group elements in the periodic table. In the present Article, we present atomic radii for the other 16; these new radii were determined in a way designed to be compatible with Bondi's scale. The method chosen is a set of two-parameter correlations of Bondi's radii with repulsive-wall distances calculated by relativistic coupled-cluster electronic structure calculations. The newly determined radii (in A) are Be, 1.53; B, 1.92; Al, 1.84; Ca, 2.31; Ge, 2.11; Rb, 3.03; Sr, 2.49; Sb, 2.06; Cs, 3.43; Ba, 2.68; Bi, 2.07; Po, 1.97; At, 2.02; Rn, 2.20; Fr, 3.48; and Ra, 2.83.

  11. van Hove Singularity Enhanced Photochemical Reactivity of Twisted Bilayer Graphene.

    PubMed

    Liao, Lei; Wang, Huan; Peng, Han; Yin, Jianbo; Koh, Ai Leen; Chen, Yulin; Xie, Qin; Peng, Hailin; Liu, Zhongfan

    2015-08-12

    Twisted bilayer graphene (tBLG) exhibits van Hove singularities (VHSs) in the density of states that can be tuned by changing the twist angle (θ), sparking various novel physical phenomena. Much effort has been devoted to investigate the θ-dependent physical properties of tBLG. Yet, the chemical properties of tBLG with VHSs, especially the chemical reactivity, remain unexplored. Here we report the first systematic study on the chemistry of tBLG through the photochemical reaction between graphene and benzoyl peroxide. Twisted bilayer graphene exhibits θ-dependent reactivity, and remarkably enhanced reactivity is obtained when the energy of incident laser matches with the energy interval of the VHSs of tBLG. This work provides an insight on the chemistry of tBLG, and the successful enhancement of chemical reactivity derived from VHS is highly beneficial for the controllable chemical modification of tBLG as well as the development of tBLG based devices.

  12. Clinical significance and prevalence of Blastocystis hominis in Van, Turkey

    PubMed Central

    Beyhan, Yunus E.; Yilmaz, Hasan; Cengiz, Zeynep T.; Ekici, Abdurrahman

    2015-01-01

    Objectives: To determine the associated clinical symptoms and prevalence of Blastocystis hominis (B. hominis). Methods: Stool samples of 50,185 patients (26,784 males and 23,401 females) who were received at the Parasitology Laboratory of Yuzuncu Yil University Faculty of Medicine, Van, Turkey in the last 5 years were inspected microscopically using saline and iodine-stained wet-mount preparations. Age, gender, and symptoms of patients were recorded and their significance was evaluated. Results: The prevalence of B. hominis in the total sample was 0.54% (275/50185). Out of 275 infected patients, 143 (52%) were males, and 132 (48%) were female (χ2=0.884; p=0.348). The distribution of B. hominis infection was high in 7-13 aged children (34.9%) (χ2=306.8; p=0.001). Blastocystis was higher among symptomatic patients (70.2%) compared with asymptomatic patients (29.8%) (χ2=107.13; p=0.001). The most frequent clinical symptoms associated with the disease were abdominal pain (27.3%) and diarrhea (19.6%) followed by anorexia, fever, saliva, anal itching, and nausea. Conclusion: Blastocystis hominis is considered a causative agent of human disease in patients with recurrent symptoms. Due to the significant risk for zoonotic transmission, molecular techniques must be used to determine the route and source of infection. PMID:26318472

  13. Van Der Pol model of a Cerenkov maser

    SciTech Connect

    Kleckner, M.; Ron, A.; Botton, M.

    1995-12-31

    A non-linear analysis of a Cerenkov maser is presented. The system consists of a ring configuration of a cylindrical waveguide filled with a dielectric material. A single transverse-magnetic mode is assumed to propagate in the system. A low-density pencil electron beam travels in part of the ring, confined by a strong axial magnetic field. Using the single-particle description for the beam and the wave equation for the field, we obtain a set of two coupled non-linear differential equations describing the slowly varying amplitude and phase of the electromagnetic mode. The gain per path is assumed to be small and the spatial growth of the field is neglected. The resulting time dependent amplitude includes the exponential gain of the linear stage and the saturation to its maximum value. The time dependent frequency is also calculated. The two equations are combined to a single Van Der Pol equation with a non-linear restoring force. This description demonstrates the similarities and differences between the Cerenkov maser and other lasing systems.

  14. Abnormal brain structure in adults with Van der Woude syndrome.

    PubMed

    Nopoulos, P; Richman, L; Andreasen, N C; Murray, J C; Schutte, B

    2007-06-01

    Van der Woude syndrome (VWS) is an autosomal dominant disorder manifested in cleft lip and/or palate and lip pits. Isolated clefts of the lip and/or palate (ICLP) have both genotype and phenotype overlap with VWS. Subjects with ICLP have abnormalities in brain structure and function. Given the similarities between VWS and ICLP, the current study was designed to evaluate the pattern of brain structure of adults with VWS. Fourteen adults with VWS were compared to age- and gender-matched healthy controls. Brain structure was evaluated using magnetic resonance imaging. All subjects with VWS had enlarged volumes of the anterior regions of the cerebrum. Men with VWS had reduced volumes of the posterior cerebrum. Anterior cerebrum volume was negatively correlated with intelligent quotient in the subjects with VWS indicating that the enlargement of this brain region was 'pathologic.' The pattern of brain structure in VWS is nearly identical to those seen in ICLP. In addition, men are affected more severely. Pathologic enlargement of the tissue and a gender effect with men affected more severely are common features of neurodevelopmental disorders supporting the notion that the brain structure of VWS and ICLP may be because of abnormal brain development. PMID:17539900

  15. Synchronization of two memristively coupled van der Pol oscillators

    NASA Astrophysics Data System (ADS)

    Ignatov, M.; Hansen, M.; Ziegler, M.; Kohlstedt, H.

    2016-02-01

    The objective of this letter is to convey two essential principles of biological computing—synchronization and memory—in an electronic circuit with two van der Pol (vdP) oscillators coupled via a memristive device. The coupling was mediated by connecting the gate terminals of two programmable unijunction transistors through a resistance-capacitance network comprising an Ag-TiOx-Al memristive device. In the high resistance state the memristance was in the order of MΩ, which leads to two independent self-sustained oscillators characterized by the different frequencies f1 and f2 and no phase relation between the oscillations. Depending on the mediated pulse amplitude, the memristive device switched to the low resistance state after a few cycles and a frequency adaptation and phase locking were observed. The experimental results are underlined by theoretically considering a system of two coupled vdP equations. This experiment may pave the way to larger neuromorphic networks in which the coupling parameters (through memristive devices) can vary in time and strength and are able to remember the history of applied electrical potentials.

  16. Growth charts for children with Ellis-van Creveld syndrome.

    PubMed

    Verbeek, Sabine; Eilers, Paul H C; Lawrence, Kate; Hennekam, Raoul C M; Versteegh, Florens G A

    2011-02-01

    Ellis-van Creveld (EvC) syndrome is a congenital malformation syndrome with marked growth retardation. In this study, specific growth charts for EvC patients were derived to allow better follow-up of growth and earlier detection of growth patterns unusual for EvC. With the use of 235 observations of 101 EvC patients (49 males, 52 females), growth charts for males and females from 0 to 20 years of age were derived. Longitudinal and cross-sectional data were collected from an earlier review of growth data in EvC, a database of EvC patients, and from recent literature. To model the growth charts, the GAMLSS package for the R statistical program was used. Height of EvC patients was compared to healthy children using Dutch growth charts. Data are presented both on a scale for age and on a scale for the square root of age. Compared to healthy Dutch children, mean height standard deviation score values for male and female EvC patients were -3.1 and -3.0, respectively. The present growth charts should be useful in the follow-up of EvC patients. Most importantly, early detection of growth hormone deficiency, known to occur in EvC, will be facilitated.

  17. Spatially Correlated Disorder in Epitaxial van der Waals Heterostructures

    NASA Astrophysics Data System (ADS)

    Laanait, Nouamane; Zhang, Zhan; Schleputz, Christian; Liu, Ying; Wojcik, Michael; Myers-Ward, Rachael; Gaskill, D. Kurt; Fenter, Paul; Li, Lian

    The structural cohesion of van der Waals (vdW) heterostructures relies upon a cooperative balance between strong intra-layer bonded interactions and weak inter-layer coupling. The confinement of extended defects to within a single vdW layer and competing interactions introduced by epitaxial constraints could generate fundamentally new structural disorders. Here we report on the presence of spatially correlated and localized disorder states that coexist with the near perfect crystallographic order along the growth direction of epitaxial vdW heterostructure of Bi2Se3/graphene/SiC grown by molecular beam epitaxy. With the depth penetration of hard X-ray diffraction microscopy and high-resolution surface scattering, we imaged local structural configurations from the atomic to mesoscopic length scales, and found that these disorder states result as a confluence of atomic scale modulations in the strength of vdW layer-layer interactions and nanoscale boundary conditions imposed by the substrate. These findings reveal a vast landscape of novel disorder states that can be manifested in epitaxial vdW heterostructures. Supported by the Wigner Fellowship program at Oak Ridge Nat'l Lab.

  18. Scientia sexualis versus ars erotica: Foucault, van Gulik, Needham.

    PubMed

    Rocha, Leon Antonio

    2011-09-01

    This paper begins with a discussion of the scientia sexualis/ars erotica distinction, which Foucault first advances in History of Sexuality Vol. 1, and which has been employed by many scholars to do a variety of analytical work. Though Foucault has expressed his doubts regarding his conceptualization of the differences between Western and Eastern discourses of desire, he never entirely disowns the distinction. In fact, Foucault remains convinced that China must have an ars erotica. I will explore Foucault's sources of authority. To this end, I introduce the work of famous Dutch sinologist Robert Hans van Gulik, who published the tremendously influential Sexual Life in Ancient China in 1961, and also explore Joseph Needham's view on Chinese sex. I argue that, Foucault, in his fierce polemic against the "Repressive Hypothesis", himself imagined a utopian Other where pleasure and desire were organised differently. I end on a discuss on Orientalism and the project of "Sinography" of comparative literature scholars Haun Saussy, Eric Hayot and others.

  19. The van der Waals potential of the magnesium dimer.

    PubMed

    Li, P; Xie, W; Tang, K T

    2010-08-28

    The ground state van der Waals potential of the magnesium dimer is described by the Tang-Toennies potential model, which requires five essential parameters. Among them, the three dispersion coefficients C(6), C(8), and C(10) are available from accurate ab initio calculations. The other two are the Born-Mayer parameters in A exp(-bR). In this paper, we show that A and b can be determined from the self-consistent Hartree-Fock calculations and the experimental dissociation energy D(0). The predicted well depth D(e) and equilibrium distance R(e) are in nearly perfect agreement with the experiment. In fact, the entire potential energy curve, which is given by a single analytic function, is in excellent agreement with the pointwise potential energies constructed from the spectroscopic measurements in the interval of 6a(0)-14a(0) and in good agreement with the experimental repulsive potential determined from Franck-Condon factors of the bound-free transitions for R less than 6a(0). The reduced potential of Mg(2) is analyzed in terms of its components, and the number of terms in the dispersion series necessary for convergence is investigated.

  20. Butterfly inclusions in Van Schrieck masterpieces. Techniques and optical properties

    NASA Astrophysics Data System (ADS)

    Berthier, S.; Boulenguez, J.; Menu, M.; Mottin, B.

    2008-07-01

    Dutch painter Otto Marseus Van Schrieck (1619 1678) is famous for his invention of “sottobosco”. These specific still-life paintings are characterized by the presence of various living organisms (mainly insects and plants) directly on the canvas. We will focus our attention on the painting kept in the museum of Grenoble, France, where a real butterfly is pasted on the canvas. The actual butterfly is a common Nymphalidae, Inachis io, presented in a static position on the dorsal side, without any perspective, compared to the neighboring butterflies. The colors of this butterfly are mainly due to pigments, melanin (black to brown) and ommochromes (yellow, orange, red) often in granules configuration that introduce scattering of light superimposed to the classical selective absorption, except in the ocelli of the hind wings where the blue coloration is due to interferential effects. The nearly perfect refraction index equality between the varnish and the chitin, the main constituent of the butterfly wings, deeply affects its colors. This leads the artist to a final intervention in some parts of the wings, revealed by microscope observation.

  1. Nanoindentation and the micromechanics of Van Gogh oil paints

    NASA Astrophysics Data System (ADS)

    Salvant, Johanna; Barthel, Etienne; Menu, Michel

    2011-08-01

    Understanding the mechanical properties of ancient paintings is a major issue for conservation and restoration. One strategy is to measure the mechanical properties of reconstructed paints: however, the aging process is poorly known, so it is also desirable to measure mechanical properties directly on ancient paint samples. Using nanoindentation, we have characterized submillimetric samples recovered from restoration of two Van Gogh paintings and compared the results with reconstructed paint samples. We demonstrate that the reduced modulus and hardness of historical paints can be measured at a very local scale, even differentiating between each paint layer. Our reconstructed paint samples exhibit elastic moduli comparable to values of the literature, but the values measured on the two 19th century paint samples are found to be significantly larger. Similarly, the compositional dependence of the elastic modulus is consistent with literature results for our reconstructed samples while our preliminary results for ancient samples do not readily fall into the same pattern. These results all point out to a significant impact of long term aging, in a manner which is difficult to predict in our present state of understanding. They demonstrate that nanoindentation is a very adequate tool to improve our knowledge of art paint mechanics and aging.

  2. The Benton-Van Allen faces: a lateralized tachistoscopic study.

    PubMed

    Püschel, J; Zaidel, E

    1994-03-01

    The Benton-Van Allen Facial Recognition Test (FRT) was adapted to a lateralized same-different task. The lateralized same targets were either physically identical to the central upright faces or had the same face identity but were transformed (3/4-views or shadowed faces). Faces were also modified to include or exclude external features. There was a left hemifield (right hemisphere) advantage only for the most difficult, shadowed faces. The absence of a left hemifield advantage for the matching of upright faces to identical or 3/4-view faces shows bilateral competence for face processing, both by physical and by face identity, and confirms previous observations that the FRT does not discriminate left from right hemisphere-damaged patients. Removal of external features affected performance in the right but not the left visual field, suggesting that the left hemisphere uses a less feature-dependent mechanism than the right hemisphere. This effect was only present in females, who were more lateralized than males.

  3. Wave acceleration of electrons in the Van Allen radiation belts.

    PubMed

    Horne, Richard B; Thorne, Richard M; Shprits, Yuri Y; Meredith, Nigel P; Glauert, Sarah A; Smith, Andy J; Kanekal, Shrikanth G; Baker, Daniel N; Engebretson, Mark J; Posch, Jennifer L; Spasojevic, Maria; Inan, Umran S; Pickett, Jolene S; Decreau, Pierrette M E

    2005-09-01

    The Van Allen radiation belts are two regions encircling the Earth in which energetic charged particles are trapped inside the Earth's magnetic field. Their properties vary according to solar activity and they represent a hazard to satellites and humans in space. An important challenge has been to explain how the charged particles within these belts are accelerated to very high energies of several million electron volts. Here we show, on the basis of the analysis of a rare event where the outer radiation belt was depleted and then re-formed closer to the Earth, that the long established theory of acceleration by radial diffusion is inadequate; the electrons are accelerated more effectively by electromagnetic waves at frequencies of a few kilohertz. Wave acceleration can increase the electron flux by more than three orders of magnitude over the observed timescale of one to two days, more than sufficient to explain the new radiation belt. Wave acceleration could also be important for Jupiter, Saturn and other astrophysical objects with magnetic fields.

  4. Some factors affecting tannase production by Aspergillus niger Van Tieghem

    PubMed Central

    Aboubakr, Hamada A.; El-Sahn, Malak A.; El-Banna, Amr A.

    2013-01-01

    One variable at a time procedure was used to evaluate the effect of qualitative variables on the production of tannase from Aspergillus niger Van Tieghem. These variables including: fermentation technique, agitation condition, tannins source, adding carbohydrates incorporation with tannic acid, nitrogen source type and divalent cations. Submerged fermentation under intermittent shaking gave the highest total tannase activity. Maximum extracellular tannase activity (305 units/50 mL) was attained in medium containing tannic acid as tannins source and sodium nitrate as nitrogen source at 30 °C for 96 h. All added carbohydrates showed significant adverse effects on the production of tannase. All tested divalent cations significantly decreased tannase production. Moreover, split plot design was carried out to study the effect of fermentation temperature and fermentation time on tannase production. The results indicated maximum tannase production (312.7 units/50 mL) at 35 °C for 96 h. In other words, increasing fermentation temperature from 30 °C to 35 °C resulted in increasing tannase production. PMID:24294255

  5. Photocurrent generation with two-dimensional van der Waals semiconductors.

    PubMed

    Buscema, Michele; Island, Joshua O; Groenendijk, Dirk J; Blanter, Sofya I; Steele, Gary A; van der Zant, Herre S J; Castellanos-Gomez, Andres

    2015-06-01

    Two-dimensional (2D) materials have attracted a great deal of interest in recent years. This family of materials allows for the realization of versatile electronic devices and holds promise for next-generation (opto)electronics. Their electronic properties strongly depend on the number of layers, making them interesting from a fundamental standpoint. For electronic applications, semiconducting 2D materials benefit from sizable mobilities and large on/off ratios, due to the large modulation achievable via the gate field-effect. Moreover, being mechanically strong and flexible, these materials can withstand large strain (>10%) before rupture, making them interesting for strain engineering and flexible devices. Even in their single layer form, semiconducting 2D materials have demonstrated efficient light absorption, enabling large responsivity in photodetectors. Therefore, semiconducting layered 2D materials are strong candidates for optoelectronic applications, especially for photodetection. Here, we review the state-of-the-art in photodetectors based on semiconducting 2D materials, focusing on the transition metal dichalcogenides, novel van der Waals materials, black phosphorus, and heterostructures.

  6. How well do train driver's sleep in relay vans?

    PubMed

    Lamond, Nicole; Darwent, David; Dawson, Drew

    2005-01-01

    Relay working operations typically require two crews of train drivers to work a rotating 8-h schedule for two or more days. While one crew is driving, the other has the opportunity to sleep onboard the train. The current study investigated the impact of relay work on drivers sleep quantity and quality. Fourteen drivers wore wrist activity monitors and completed sleep/wake diaries for 3 d prior to and during short (<48 h) relay trips. Drivers obtained an average of 7.8 h sleep per night while at home, and an average of 4 h sleep per opportunity during the relay trip. Sleep obtained in the relay van was associated with longer sleep onset latencies, lower efficiency and poorer subjective quality than sleep at home. During the relay trip, drivers obtained significantly more sleep during opportunities that occurred in the evening, than those that occurred early morning or during the day. These findings suggest that while drivers are able to obtain sleep during short relay operations, it is of poorer quality than sleep obtained at home. Further, the timing of the sleep opportunities during the relay trip impacts on the quantity and quality of sleep obtained.

  7. Van Gogh's fantasies of replacement: being a double and a twin.

    PubMed

    Blum, Harold P

    2009-12-01

    The replacement child, often given the name of the deceased, is prone to fantasies that he or she is the embodiment of the dead child. Vincent van Gogh was born one year to the day after a stillborn brother of the identical name, including the middle name, Willem. In the parish register van Gogh was given the same number twenty-nine as his predecessor brother. Van Gogh's fantasies of death and rebirth, of being a double and a twin, contributed to both his psychopathology and his creativity. The replacement theme in van Gogh's life and work is evident in his voluminous correspondence containing drawings and references to his art. His parents and his brother Theo are viewed as having shared a familial fantasy system. Van Gogh's self-portraits are regarded as relevant to his being a replacement child. No single fantasy or theme can account for the complexities of development, disorder, or creativity. Van Gogh's art was vastly overdetermined, including extraordinary endowment and the motivation of a replacement child to justify his survival, surpass his rival double/twin through great achievement, repair parental depression, and defy death through immortality.

  8. Outbreak of vancomycin-susceptible Enterococcus faecium containing the wild-type vanA gene.

    PubMed

    Szakacs, Tom A; Kalan, Lindsay; McConnell, Michael J; Eshaghi, Alireza; Shahinas, Dea; McGeer, Allison; Wright, Gerry D; Low, Donald E; Patel, Samir N

    2014-05-01

    Accurate detection of vancomycin-resistant enterococci (VRE) is essential in preventing transmission in health care settings. Chromogenic media are widely used for screening VRE because of fast turnaround times (TAT) and high sensitivity. We report an outbreak of Enterococcus faecium bearing vanA yet susceptible to vancomycin (vancomycin-variable Enterococcus [VVE]). Between October 2009 to March 2011, clinical and screening specimens (n=14,747) were screened for VRE using VRE-selective medium and/or PCR. VVE isolates were genotyped to determine relatedness. Plasmids from these isolates were characterized by sequencing. Overall, 52 VVE isolates were identified, comprising 15% of all VRE isolates identified. Isolates demonstrated growth on Brilliance VRE agar (Oxoid) at 24 h of incubation but did not grow on brain heart infusion agar with 6 μg/ml vancomycin (Oxoid) or bile esculin azide agar with 6 μg/ml vancomycin (Oxoid) and were susceptible to vancomycin. Genotyping of 20 randomly selected VVE isolates revealed that 15/20 were identical, while 5 were highly related. PCR of the VVE transposon confirmed the presence of vanHAXY gene cluster; however, vanS (sensor) and vanR (regulator) genes were absent. The outbreak was controlled through routine infection control measures. We report an emergence of a fit strain of E. faecium containing vanA yet susceptible to vancomycin. Whether this new strain represents VRE has yet to be determined; however, unique testing procedures are required for reliable identification of VVE. PMID:24523464

  9. Outbreak of vancomycin-susceptible Enterococcus faecium containing the wild-type vanA gene.

    PubMed

    Szakacs, Tom A; Kalan, Lindsay; McConnell, Michael J; Eshaghi, Alireza; Shahinas, Dea; McGeer, Allison; Wright, Gerry D; Low, Donald E; Patel, Samir N

    2014-05-01

    Accurate detection of vancomycin-resistant enterococci (VRE) is essential in preventing transmission in health care settings. Chromogenic media are widely used for screening VRE because of fast turnaround times (TAT) and high sensitivity. We report an outbreak of Enterococcus faecium bearing vanA yet susceptible to vancomycin (vancomycin-variable Enterococcus [VVE]). Between October 2009 to March 2011, clinical and screening specimens (n=14,747) were screened for VRE using VRE-selective medium and/or PCR. VVE isolates were genotyped to determine relatedness. Plasmids from these isolates were characterized by sequencing. Overall, 52 VVE isolates were identified, comprising 15% of all VRE isolates identified. Isolates demonstrated growth on Brilliance VRE agar (Oxoid) at 24 h of incubation but did not grow on brain heart infusion agar with 6 μg/ml vancomycin (Oxoid) or bile esculin azide agar with 6 μg/ml vancomycin (Oxoid) and were susceptible to vancomycin. Genotyping of 20 randomly selected VVE isolates revealed that 15/20 were identical, while 5 were highly related. PCR of the VVE transposon confirmed the presence of vanHAXY gene cluster; however, vanS (sensor) and vanR (regulator) genes were absent. The outbreak was controlled through routine infection control measures. We report an emergence of a fit strain of E. faecium containing vanA yet susceptible to vancomycin. Whether this new strain represents VRE has yet to be determined; however, unique testing procedures are required for reliable identification of VVE.

  10. A Silenced vanA Gene Cluster on a Transferable Plasmid Caused an Outbreak of Vancomycin-Variable Enterococci

    PubMed Central

    Sivertsen, Audun; Pedersen, Torunn; Larssen, Kjersti Wik; Bergh, Kåre; Rønning, Torunn Gresdal; Radtke, Andreas

    2016-01-01

    We report an outbreak of vancomycin-variable vanA+ enterococci (VVE) able to escape phenotypic detection by current guidelines and demonstrate the molecular mechanisms for in vivo switching into vancomycin resistance and horizontal spread of the vanA cluster. Forty-eight vanA+ Enterococcus faecium isolates and one Enterococcus faecalis isolate were analyzed for clonality with pulsed-field gel electrophoresis (PFGE), and their vanA gene cluster compositions were assessed by PCR and whole-genome sequencing of six isolates. The susceptible VVE strains were cultivated in brain heart infusion broth containing vancomycin at 8 μg/ml for in vitro development of resistant VVE. The transcription profiles of susceptible VVE and their resistant revertants were assessed using quantitative reverse transcription-PCR. Plasmid content was analyzed with S1 nuclease PFGE and hybridizations. Conjugative transfer of vanA was assessed by filter mating. The only genetic difference between the vanA clusters of susceptible and resistant VVE was an ISL3-family element upstream of vanHAX, which silenced vanHAX gene transcription in susceptible VVE. Furthermore, the VVE had an insertion of IS1542 between orf2 and vanR that attenuated the expression of vanHAX. Growth of susceptible VVE occurred after 24 to 72 h of exposure to vancomycin due to excision of the ISL3-family element. The vanA gene cluster was located on a transferable broad-host-range plasmid also detected in outbreak isolates with different pulsotypes, including one E. faecalis isolate. Horizontally transferable silenced vanA able to escape detection and revert into resistance during vancomycin therapy represents a new challenge in the clinic. Genotypic testing of invasive vancomycin-susceptible enterococci by vanA-PCR is advised. PMID:27139479

  11. Van der Waals coefficients beyond the classical shell model

    SciTech Connect

    Tao, Jianmin; Fang, Yuan; Hao, Pan; Scuseria, G. E.; Ruzsinszky, Adrienn; Perdew, John P.

    2015-01-14

    Van der Waals (vdW) coefficients can be accurately generated and understood by modelling the dynamic multipole polarizability of each interacting object. Accurate static polarizabilities are the key to accurate dynamic polarizabilities and vdW coefficients. In this work, we present and study in detail a hollow-sphere model for the dynamic multipole polarizability proposed recently by two of the present authors (JT and JPP) to simulate the vdW coefficients for inhomogeneous systems that allow for a cavity. The inputs to this model are the accurate static multipole polarizabilities and the electron density. A simplification of the full hollow-sphere model, the single-frequency approximation (SFA), circumvents the need for a detailed electron density and for a double numerical integration over space. We find that the hollow-sphere model in SFA is not only accurate for nanoclusters and cage molecules (e.g., fullerenes) but also yields vdW coefficients among atoms, fullerenes, and small clusters in good agreement with expensive time-dependent density functional calculations. However, the classical shell model (CSM), which inputs the static dipole polarizabilities and estimates the static higher-order multipole polarizabilities therefrom, is accurate for the higher-order vdW coefficients only when the interacting objects are large. For the lowest-order vdW coefficient C{sub 6}, SFA and CSM are exactly the same. The higher-order (C{sub 8} and C{sub 10}) terms of the vdW expansion can be almost as important as the C{sub 6} term in molecular crystals. Application to a variety of clusters shows that there is strong non-additivity of the long-range vdW interactions between nanoclusters.

  12. The “van Zijl” Jurassic geomagnetic reversal revisited

    NASA Astrophysics Data System (ADS)

    Moulin, Maud; Courtillot, Vincent; Fluteau, FréDéRic; Valet, Jean-Pierre

    2012-03-01

    We have collected two new detailed records of what could be the second oldest well documented reversal, the "van Zijl" Jurassic (˜180 Ma) reversal recorded in the thick basalt sequences of the Karoo large igneous province in Lesotho and South Africa. Sections yielded 10 and 8 independent transitional paleomagnetic directions respectively over two continuous 130 m and 160 m sequences. The corresponding VGP reversing paths share a number of consistent features and are integrated with a third record at Bushmen's Pass from Prévot et al. (2003) to yield a single reversal path with: 1- a large directional jump with no transitional poles between 45°S and 45°N in the first, main phase of the reversal, 2- a large elongated loop (multiple hairpin) to the SE with poles going down to ˜20° latitudes in the second phase of the reversal, and 3- a rebound before finally settling in normal polarity. We have measured relative paleo-intensities on a set of carefully selected samples. Intensity was low prior to the directional changes and recovery to the following normal polarity was progressive. Transitional intensity is 80 to 90% lower than full polarity values. There is no significant increase in intensity at the time of transitional directional clusters. Our results are consistent with a weak non-dipolar reversing field, with faster and larger directional secular variation as the equator is crossed by VGPs. They tend to vindicate the notion of a short duration of the directional reversal, though one cannot draw global conclusions from a record limited to essentially a single location.

  13. Quorum sensing in Vibrio anguillarum: characterization of the vanI/vanR locus and identification of the autoinducer N-(3-oxodecanoyl)-L-homoserine lactone.

    PubMed Central

    Milton, D L; Hardman, A; Camara, M; Chhabra, S R; Bycroft, B W; Stewart, G S; Williams, P

    1997-01-01

    Certain gram-negative pathogens are known to control virulence gene expression through cell-cell communication via small diffusible signal molecules termed autoinducers. This intercellular signal transduction mechanism termed quorum sensing depends on the interaction of an N-acylhomoserine lactone (AHL) auto-inducer molecule with a receptor protein belonging to the LuxR family of positive transcriptional activators. Vibrio anguillarum is a gram-negative pathogen capable of causing a terminal hemorrhagic septicemia known as vibriosis in fish such as rainbow trout. In this study, we sought to determine whether V. anguillarum employs AHLs to regulate virulence gene expression. Spent V. anguillarum culture supernatants stimulated bioluminescence in a recombinant lux-based Escherichia coli AHL biosensor strain, whereas they both stimulated and inhibited AHL-mediated violacein pigment production in Chromobacterium violaceum. This finding suggested that V. anguillarum may produce multiple AHL signal molecules. Using high-performance liquid chromatography and high-resolution tandem mass spectrometry, we identified the major V. anguillarum AHL as N-(3-oxodecanoyl)-L-homoserine lactone (ODHL), a structure which was unequivocally confirmed by chemical synthesis. The gene (vanI) responsible for ODHL synthesis was cloned and sequenced and shown to belong to the LuxI family of putative AHL synthases. Further sequencing downstream of vanI revealed a second gene (vanR) related to the LuxR family of transcriptional activators. Although deletion of vanI abolished ODHL synthesis, no reduction of either metalloprotease production or virulence in a fish infection model was observed. However, the vanI mutant remained capable of weakly activating both bioluminescence and violacein in the E. coli and C. violaceum biosensors, respectively, indicating the existence of additional layers of AHL-mediated regulatory complexity. PMID:9139920

  14. Clamping instability and van der Waals forces in carbon nanotube mechanical resonators.

    PubMed

    Aykol, Mehmet; Hou, Bingya; Dhall, Rohan; Chang, Shun-Wen; Branham, William; Qiu, Jing; Cronin, Stephen B

    2014-05-14

    We investigate the role of weak clamping forces, typically assumed to be infinite, in carbon nanotube mechanical resonators. Due to these forces, we observe a hysteretic clamping and unclamping of the nanotube device that results in a discrete drop in the mechanical resonance frequency on the order of 5-20 MHz, when the temperature is cycled between 340 and 375 K. This instability in the resonant frequency results from the nanotube unpinning from the electrode/trench sidewall where it is bound weakly by van der Waals forces. Interestingly, this unpinning does not affect the Q-factor of the resonance, since the clamping is still governed by van der Waals forces above and below the unpinning. For a 1 μm device, the drop observed in resonance frequency corresponds to a change in nanotube length of approximately 50-65 nm. On the basis of these findings, we introduce a new model, which includes a finite tension around zero gate voltage due to van der Waals forces and shows better agreement with the experimental data than the perfect clamping model. From the gate dependence of the mechanical resonance frequency, we extract the van der Waals clamping force to be 1.8 pN. The mechanical resonance frequency exhibits a striking temperature dependence below 200 K attributed to a temperature-dependent slack arising from the competition between the van der Waals force and the thermal fluctuations in the suspended nanotube. PMID:24758201

  15. Van, Turkey earthquake of 23 october 2011, mw 7.2; an overview on disaster management.

    PubMed

    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

  16. Comparing heat exchangers of thermacoustic prime movers with a Van der Pol model

    NASA Astrophysics Data System (ADS)

    Cox, I.; Jorgensen, M.; Andersen, B.

    2010-10-01

    A thermoacoustic standing-wave prime mover is a self-sustained oscillator whose initial growth of acoustic pressure into amplitude saturation can be modeled by the Van der Pol equation. The nonlinear Van der Pol equation is calculated computationally, using 4^th order Runge-Kutta. The Van der Pol model gives quantitative loss and gain parameters, when using a best-fit with experimental data. The engines tested in this study have an average frequency of 2700 Hz, which suggests that the first second of oscillations when using the Van der Pol model can reveal information about the steady-state performance of the device. This model is applied to studying the effect of different heat exchanger sizes. All sixteen possible permutations were tested using different copper wire mesh dimensions: 24X24, 40X40, 60X60, and 80X80 for the hot and cold heat exchangers (where ##X## indicates wires per inch). Plotting the steady-state acoustic pressure as a function of the gain term divided by the loss term shows roughly, a linear relationship. The engine with the highest gain term and smallest loss term was using 80X80 for the hot heat exchanger combined with the 24X24 for the cold heat exchanger and is consistent with the highest steady-state pressure achieved. The modeling process has been very successful and fits the Van der Pol equation.

  17. 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.

  18. 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

  19. Pathologies of van Stockum dust/Tipler's time machine

    NASA Astrophysics Data System (ADS)

    Lindsay, David S.

    2016-09-01

    We study the internal solution, and external vacuum solution for radial cutoff, of "van Stockum dust", an infinitely long rotating pressureless dust column; its density increases with radius. This interesting but poorly explored spacetime turns out to have a number of exotic properties, especially in the external vacuum region. These solutions have been known for decades, but it seems that they have never been investigated in detail. In this paper we analyze them and describe their peculiar properties. There are three regimes of radial cutoff that are of interest: (1) If the dust column is thick enough that closed timelike loops (CTLs or "time machines") exist inside the column, then the radius of the entire "universe" is finite, and in fact does not extend much beyond the edge of the matter, even though the metric's radial parameter is unbounded. This interesting finite proper radius seems to have been missed by earlier investigators. Other exotic properties of the external vacuum in this regime: CTLs exist in cylindrical shells, alternating with shells having no circular CTLs; there are infinitely many such shells, getting closer and closer together as one gets farther from the rotation axis. Also, a separate set of infinitely many cylindrical shells exists, having what might be termed "extreme frame-dragging", within which motion is possible only in one direction; they alternate with "normal" shells allowing motion in either direction. Gravitational attraction and tides increase with distance from the matter column, and diverge at the "edge of the universe". In addition, though the radius of the universe is finite, its circumference is infinite; and its boundary is a circle, not a cylinder (the z-axis has shrunk to nothing at the edge). (2) For smaller radial cutoff, but still large enough to produce CTLs, the radius of the universe is infinite; but there are still infinitely many cylindrical shells of CTLs alternating with non-CTL shells. However, the innermost

  20. 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.

  1. First report of VanA Enterococcus gallinarum dissemination within an intensive care unit in Argentina.

    PubMed

    Corso, A; Faccone, D; Gagetti, P; Togneri, A; Lopardo, H; Melano, R; Rodríguez, V; Rodriguez, M; Galas, M

    2005-01-01

    Enterococcusgallinarum is intrinsically resistant to low levels of vancomycin and has been described as a colonizing microorganism causing bacteraemia and infection among immunosupresed patients. Between August 2000 and February 2001, 15 highly glycopeptide-resistant E. gallinarum isolates, one from blood and the remaining from rectal swabs, were recovered in a general hospital of Buenos Aires Province, Argentina. All isolates were characterized by biochemical assays, and displayed MICs of vancomycin in the range 16-128 mg/l and MICs of teicoplanin in the range 16-32 mg/l. In all cases, PCR analysis yield positive results for both vanC1 and vanA genes. E. gallinarum isolates were classified as two clonal types by SmaI-PFGE: clone A (n = 8) and clone B (n = 7) and both harboured a transferable vanA element.

  2. Analysis of life cycle costs for electric vans with advanced battery systems

    SciTech Connect

    Marr, W.W.; Walsh, W.J.; Miller, J.F.

    1989-01-01

    The performance of advanced Zn/Br/sub 2/, LiAl/FeS, Na/S, Ni/Fe, and Fe/Air batteries in electric vans was compared to that of tubular lead-acid technology. The MARVEL computer analysis system evaluated these batteries for the G-Van and IDSEP vehicles over two driving schedules. Each of the advanced batteries exhibited the potential for major improvements in both range and life cycle cost compared with tubular lead-acid. A sensitivity analysis reveals specific energy, battery initial cost, and cycle life to be the dominant factors in reducing life cycle cost for the case of vans powered by tubular lead-acid batteries.

  3. Analysis of life cycle costs for electric vans with advanced battery systems

    SciTech Connect

    Marr, W.W.; Walsh, W.J.; Miller, J.F.

    1988-11-01

    The performance of advanced Zn/Br/sub 2/, LiAl/FeS, Na/S, Ni/Fe, and Fe/Air batteries in electric vans was compared to that of tubular lead-acid technology. The MARVEL computer analysis system evaluated these batteries for the G-Van and IDSEP vehicles over two driving schedules. Each of the advanced batteries exhibited the potential for major improvements in both range and life cycle cost compared with tubular lead-acid. A sensitivity analysis revealed specific energy, battery initial cost, and cycle life to be the dominant factors in reducing life cycle cost for the case of vans powered by tubular lead-acid batteries. 5 refs., 8 figs., 2 tabs.

  4. Sample size estimation for the van Elteren test--a stratified Wilcoxon-Mann-Whitney test.

    PubMed

    Zhao, Yan D

    2006-08-15

    The van Elteren test is a type of stratified Wilcoxon-Mann-Whitney test for comparing two treatments accounting for strata. In this paper, we study sample size estimation methods for the asymptotic version of the van Elteren test, assuming that the stratum fractions (ratios of each stratum size to the total sample size) and the treatment fractions (ratios of each treatment size to the stratum size) are known in the study design. In particular, we develop three large-sample sample size estimation methods and present a real data example to illustrate the necessary information in the study design phase in order to apply the methods. Simulation studies are conducted to compare the performance of the methods and recommendations are made for method choice. Finally, sample size estimation for the van Elteren test when the stratum fractions are unknown is also discussed.

  5. Oral manifestations in Ellis-van Creveld syndrome: report of five cases.

    PubMed

    Cahuana, Abel; Palma, Camila; Gonzáles, Wilber; Geán, Esther

    2004-01-01

    Ellis-van Creveld syndrome, or chondroectodermal dysplasia, is an autosomal recessive disorder with characteristic clinical manifestations. Its incidence in the general population is low. The oral manifestations of Ellis-van Creveld are found in soft tissues and teeth, but the dental literature on the subject is scarce. In the last 20 years, 5 cases of Ellis-van Creveld syndrome have been followed at the Pediatric Dentistry Service of the Hospital Sant Joan de Déu, Barcelona. The present study describes the constant and variable oral findings in these patients, which play an important role in the diagnosis criteria for the syndrome. The presence of a great variety of oral manifestations such as fusion of the upper lip to the gingival margin, presence of multiple frenula, abnormally shaped and microdontic teeth, and congenitally missing teeth requires multidisciplinary dental treatment, with consideration for the high incidence of cardiac defects in these patients. PMID:15185812

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    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.

  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. Space Weather data processing and Science Gateway for the Van Allen Probes

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    A near real-time data processing pipeline for the Space Weather broadcast data from the Van Allen Probes is presented. The Van Allen Probes broadcasts a sub-set of the science data in real-time when not downlinking the principal science data. This broadcast is received by several ground stations and relayed to APL in near real time to be ingested into the space weather processing pipeline. This pipeline processes the available level zero space weather data into higher level science data products. These products are made available to the public via the Van Allen Probes Science Gateway website (http://athena.jhuapl.edu). The website acts as pivotal point though which all other instrument SOC's can be accessed. Several other data products (e.g KP/DST indices) and tools (e.g orbit calculator) are made also available to the general public.

  10. 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).

  11. van der Waals interaction between a microparticle and a single-walled carbon nanotube

    SciTech Connect

    Blagov, E. V.; Mostepanenko, V. M.; Klimchitskaya, G. L.

    2007-06-15

    The Lifshitz-type formulas describing the free energy and the force of the van der Waals interaction between an atom (molecule) and a single-walled carbon nanotube are obtained. The single-walled nanotube is considered as a cylindrical sheet carrying a two-dimensional free-electron gas with appropriate boundary conditions on the electromagnetic field. The obtained formulas are used to calculate the van der Waals free energy and force between a hydrogen atom (molecule) and single-walled carbon nanotubes of different radii. Comparison studies of the van der Waals interaction of hydrogen atoms with single-walled and multiwalled carbon nanotubes show that depending on atom-nanotube separation distance, the idealization of graphite dielectric permittivity is already applicable to nanotubes with only two or three walls.

  12. The role of collective motion in the ultrafast charge transfer in van der Waals heterostructures

    PubMed Central

    Wang, Han; Bang, Junhyeok; Sun, Yiyang; Liang, Liangbo; West, Damien; Meunier, Vincent; Zhang, Shengbai

    2016-01-01

    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 interface. Application to the MoS2/WS2 heterostructure yields good agreement with experiments, indicating near complete charge transfer within a timescale of 100 fs. PMID:27160484

  13. William P. Van Wagenen (1897-1961): pupil, mentor, and neurosurgical pioneer.

    PubMed

    Kimmell, Kristopher T; Petraglia, Anthony L; Ballou, Mary Ann; Pilcher, Webster H

    2013-09-01

    William Perrine ("Van") Van Wagenen (1897-1961) was the first Chief of Neurosurgery at the University of Rochester Medical Center (URMC), serving from 1928 to 1954, and was a leading figure in 20th-century neurosurgery. He was a devoted pupil of Dr. Harvey Cushing and helped to found the Harvey Cushing Society (now the AANS) in honor of his mentor and was elected as its first President in 1932. He served as the 27th President of the Society of Neurological Surgeons in 1952. Upon his death in 1961 he bequeathed an endowment for the Van Wagenen Fellowship, which has advanced the education of many leaders in American neurosurgery. His legacy of operative skill, his commitment to resident education and research in neurological disease, his inspiration for the foundation of the Cushing Brain Tumor registry, and his contributions to organized neurosurgery form the foundation of the legacy of neurosurgery at URMC. PMID:23662824

  14. Quantum vacuum photon modes and repulsive Lifshitz-van der Waals interactions

    NASA Astrophysics Data System (ADS)

    Dellieu, Louis; Deparis, Olivier; Muller, Jérôme; Kolaric, Branko; Sarrazin, Michaël

    2015-12-01

    The bridge between quantum vacuum photon modes and properties of patterned surfaces is currently being established on solid theoretical grounds. Based on these foundations, the manipulation of quantum vacuum photon modes in a nanostructured cavity is theoretically shown to be able to change the Lifshitz-van der Waals forces from attractive to repulsive regime. Since this concept relies on surface nanopatterning instead of chemical composition changes, it drastically relaxes the usual conditions for achieving repulsive Lifshitz-van der Waals forces. As a case study, the potential interaction energy between a nanopatterned polyethylene slab and a flat polyethylene slab with water as the intervening medium is calculated. Extremely small corrugation heights (<10 nm) are shown to be able to change the Lifshitz-van der Waals force from attractive to repulsive, the interaction strength being controlled by the corrugation height. This new approach could lead to various applications in surface science.

  15. Conjugate observations of quasiperiodic emissions by the Cluster, Van Allen Probes, and THEMIS spacecraft

    NASA Astrophysics Data System (ADS)

    Němec, F.; Hospodarsky, G.; Pickett, J. S.; Santolík, O.; Kurth, W. S.; Kletzing, C.

    2016-08-01

    We present results of a detailed analysis of two electromagnetic wave events observed in the inner magnetosphere at frequencies of a few kilohertz, which exhibit a quasiperiodic (QP) time modulation of the wave intensity. The events were observed by the Cluster and Van Allen Probes spacecraft and in one event also by the THEMIS E spacecraft. The spacecraft were significantly separated in magnetic local time, demonstrating a huge azimuthal extent of the events. Geomagnetic conditions at the times of the observations were very quiet, and the events occurred inside the plasmasphere. The modulation period observed by the Van Allen Probes and THEMIS E spacecraft (duskside) was in both events about twice larger than the modulation period observed by the Cluster spacecraft (dawnside). Moreover, individual QP elements occur about 15 s earlier on THEMIS E than on Van Allen Probes, which might be related to a finite propagation speed of a modulating ULF wave.

  16. 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.

  17. Sample size estimation for the van Elteren test--a stratified Wilcoxon-Mann-Whitney test.

    PubMed

    Zhao, Yan D

    2006-08-15

    The van Elteren test is a type of stratified Wilcoxon-Mann-Whitney test for comparing two treatments accounting for strata. In this paper, we study sample size estimation methods for the asymptotic version of the van Elteren test, assuming that the stratum fractions (ratios of each stratum size to the total sample size) and the treatment fractions (ratios of each treatment size to the stratum size) are known in the study design. In particular, we develop three large-sample sample size estimation methods and present a real data example to illustrate the necessary information in the study design phase in order to apply the methods. Simulation studies are conducted to compare the performance of the methods and recommendations are made for method choice. Finally, sample size estimation for the van Elteren test when the stratum fractions are unknown is also discussed. PMID:16372389

  18. William P. Van Wagenen (1897-1961): pupil, mentor, and neurosurgical pioneer.

    PubMed

    Kimmell, Kristopher T; Petraglia, Anthony L; Ballou, Mary Ann; Pilcher, Webster H

    2013-09-01

    William Perrine ("Van") Van Wagenen (1897-1961) was the first Chief of Neurosurgery at the University of Rochester Medical Center (URMC), serving from 1928 to 1954, and was a leading figure in 20th-century neurosurgery. He was a devoted pupil of Dr. Harvey Cushing and helped to found the Harvey Cushing Society (now the AANS) in honor of his mentor and was elected as its first President in 1932. He served as the 27th President of the Society of Neurological Surgeons in 1952. Upon his death in 1961 he bequeathed an endowment for the Van Wagenen Fellowship, which has advanced the education of many leaders in American neurosurgery. His legacy of operative skill, his commitment to resident education and research in neurological disease, his inspiration for the foundation of the Cushing Brain Tumor registry, and his contributions to organized neurosurgery form the foundation of the legacy of neurosurgery at URMC.

  19. Hydrology and land use in Van Buren County, Michigan

    USGS Publications Warehouse

    Cummings, T.R.; Twenter, F.R.; Holtschlag, D.J.

    1984-01-01

    This report gives the results of an investigation to determine the chemical and physical characteristics of ground and surface water in Van Buren County and to relate these characteristics to the agricultural use of land. Chemical inputs to the hydrologic system, including those from precipitation, animal wastes, septic tanks, and fertilizers, are assessed. Land-use, geologic setting, and hydrologic conditions are given as a necessary framework for interpretations. The land surface in Van Buren county in southwestern Michigan is flat to rolling, and ranges in altitude from 580 to 1,050 feet. About 30,000 acres or 7.4 percent of land is irrigated. Annual precipitation ranges from 34 to 36 inches. Two rivers--the Paw Paw and South Branch Black--drain most of the county. During this study, the maximum discharge of the Paw Paw River was 2,500 cubic feet per second; the minimum discharge was 202 cubic feet per second. The average discharge of the South Branch Black River during a 17- year period of record has been 106 cubic feet per second. Glacial deposits are the principal source of ground-water supplies. These deposits range in thickness from 100 to 600 feet and consist of till, outwash, and materials of lacustrine and eolian origin. In places the deposits fill buried valleys that are as much as 400 feet deep. The Coldwater Shale of Mississippian age, which underlies the glacial deposits, is mostly shale and usually yields only small amounts of salty water. Of the glacial deposits, outwash is the most productive aquifer. Most domestic wells obtain water from outwash at depths ranging from 15 to 160 feet. Irrigation wells capable of yielding 1,000 gallons per minute generally are about 200 feet deep. In places in the western part of the county, glacial deposits, which are several hundred feet thick, are mostly clay and yield little or no water. Areal variations in the chemical and physical characteristics of ground and surface water are related to land use and

  20. 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

  1. Van-Gogh-like 2 antagonises the canonical WNT pathway and is methylated in colorectal cancers

    PubMed Central

    Piazzi, G; Selgrad, M; Garcia, M; Ceccarelli, C; Fini, L; Bianchi, P; Laghi, L; D'Angelo, L; Paterini, P; Malfertheiner, P; Chieco, P; Boland, C R; Bazzoli, F; Ricciardiello, L

    2013-01-01

    Background: Aberrant activation of the canonical WNT signaling is a feature of colorectal cancer (CRC). Van-Gogh-like 2 (VANGL2) belongs to the non-canonical WNT pathway whose activation inhibits canonical WNT signaling. In this study, we investigated the role of VANGL2 and its epigenetic regulation in CRC. Methods: Van-Gogh-like 2 expression and promoter methylation after 5-aza-2′-deoxycytidine (5-aza) treatment were evaluated in CRC cells. DNA samples from 418 sporadic CRCs were tested for VANGL2 promoter methylation and microsatellite instability (MSI). Proliferation, colony formation and activation of the WNT pathway were tested in cells after VANGL2 overexpression. Results: Van-Gogh-like 2 mRNA was significantly higher in 5-aza-treated RKO, LOVO and SW48, whereas no differences were found in SW480. Van-Gogh-like 2 was fully methylated in RKO, SW48, HCT116, DLD1 and Caco2; partially methylated in LOVO, LS174T and SW837; and unmethylated in SW480, SW620 and HT29. Higher expression of VANGL2 mRNA was found in the unmethylated cell lines. In CRC specimens (8.93% MSI), methylated VANGL2 was associated with MSI, higher grade, proximal colon location and BRAF mutation. Van-Gogh-like 2 overexpression in SW480 significantly decreased proliferation, colony formation and β-catenin levels. Conclusion: Van-Gogh-like 2 is frequently methylated in MSI-CRCs with BRAF mutation and may act as a tumour suppressor gene, counteracting WNT/β-catenin signaling. PMID:23579212

  2. Role of the Vision Van, a mobile ophthalmic outpatient clinic, in the Great East Japan Earthquake

    PubMed Central

    Yuki, Kenya; Nakazawa, Toru; Kurosaka, Daijiro; Yoshida, Tsunehiko; Alfonso, Eduardo C; Lee, Richard K; Takano, Shigeru; Tsubota, Kazuo

    2014-01-01

    Purpose The Great East Japan Earthquake of March 11, 2011 triggered powerful tsunami waves off the northeastern Pacific coast of Japan that destroyed almost all of the built-up areas along the coast. The study reported here examined the role played by the Vision Van, a mobile outpatient ophthalmological clinic, in providing eye care to disaster evacuees. Methods This was a retrospective case-series study of 2,070 victims (male: 732, female: 1,338) who visited the Vision Van. The subjects’ medical records were examined retrospectively and analyzed in terms of age, sex, and date of visit to the Vision Van. Information regarding each patient’s chief complaint, diagnosis, medication(s) prescribed, and eyeglasses and contact lenses provided, was also examined. Results The Vision Van was used to conduct medical examinations on 39 days between April 23 and June 29, 2011. The average number of subjects visiting the Vision Van each day was 53±31 (range: 7–135), with examinations carried out in Miyagi Prefecture and Iwate Prefecture. The most frequent complaint was a need for eye drops (871/2,070 [42.1%]). The second and third most frequent complaints, respectively, were the need for contact lenses (294/2,070 [14.2%]) and eyeglasses (280/2,070 [13.5%]). The most frequent ocular disease diagnosis was cataract (497/2,070 [24.0%]). Eye drops were prescribed to 74.1% of the subjects. Conclusion Mobile clinics such as the Vision Van provide valuable care, in this case, particularly to individuals who lost or left behind eyeglasses or contact lenses while escaping a natural disaster, and to subjects with chronic eye disease. PMID:24741288

  3. 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.

  4. Analyzing Longitudinal Magnetoresistance Asymmetry to Quantify Doping Gradients: Generalization of the van der Pauw Method

    NASA Astrophysics Data System (ADS)

    Zhou, Wang; Yoo, H. M.; Prabhu-Gaunkar, S.; Tiemann, L.; Reichl, C.; Wegscheider, W.; Grayson, M.

    2015-10-01

    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.

  5. General theory based on fluctuational electrodynamics for van der Waals interactions in colloidal systems

    SciTech Connect

    Yannopapas, Vassilios

    2007-12-15

    A rigorous theory for the determination of the van der Waals interactions in colloidal systems is presented. The method is based on fluctuational electrodynamics and a multiple-scattering method which provides the electromagnetic Green's tensor. In particular, expressions for the Green's tensor are presented for arbitrary, finite collections of colloidal particles, for infinitely periodic or defected crystals, as well as for finite slabs of crystals. The presented formalism allows for ab initio calculations of the van der Waals interactions in colloidal systems since it takes fully into account retardation, many-body, multipolar, and near-field effects.

  6. 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. PMID:27563733

  7. Chemical reaction rates using the semiclassical Van-Vleck initialvalue representation

    SciTech Connect

    Venkataraman, Charulatha; Miller, William H.

    2006-11-29

    A semiclassical IVR formulation using the Van-Vleck propagator has been used to calculate the flux correlation function and thereby reaction rate constants. This Van-Vleck formulation of the flux-flux correlation function is computationally as simple as the classical Wigner model. However unlike the latter, it has the ability to capture quantum interference/coherence effects. Classical trajectories are evolved starting from the dividing surface that separates reactants and products, and are evolved negatively in time. This formulation has been tested on model problems ranging from the Eckart barrier, double well to the collinear H + H{sub 2}.

  8. 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.

  9. Robert Jemison ``Tee'' Van de Graaff: From Football Fields to Electric Fields

    NASA Astrophysics Data System (ADS)

    Graham, M. Talmage; Young, James

    2004-11-01

    Robert Van de Graaff's three older brothers made the family name famous in football, and it seemed that Robert was also headed toward being a sports star. Unfortunately, his football career was cut short by an injury. However, it is interesting to note that principles involved in his most memorable invention have some remarkable analogs in that sport. Few details of Robert's early life have heretofore been published. The purpose of this paper, during the 75th anniversary year of the invention of the Van de Graaff generator, is to provide some of this interesting historical background.

  10. Solution phase van der Waals epitaxy of ZnO wire arrays

    NASA Astrophysics Data System (ADS)

    Zhu, Yue; Zhou, Yong; Bakti Utama, Muhammad Iqbal; Mata, María De La; Zhao, Yanyuan; Zhang, Qing; Peng, Bo; Magen, Cesar; Arbiol, Jordi; Xiong, Qihua

    2013-07-01

    As an incommensurate epitaxy, van der Waals epitaxy allows defect-free crystals to grow on substrates even with a large lattice mismatch. Furthermore, van der Waals epitaxy is proposed as a universal platform where heteroepitaxy can be achieved irrespective of the nature of the overlayer material and the method of crystallization. Here we demonstrate van der Waals epitaxy in solution phase synthesis for seedless and catalyst-free growth of ZnO wire arrays on phlogopite mica at low temperature. A unique incommensurate interface is observed even with the incomplete initial wetting of ZnO onto the substrate. Interestingly, the imperfect contacting layer does not affect the crystalline and optical properties of other parts of the wires. In addition, we present patterned growth of a well-ordered array with hexagonal facets and in-plane alignment. We expect our seedless and catalyst-free solution phase van der Waals epitaxy synthesis to be widely applicable in other materials and structures.As an incommensurate epitaxy, van der Waals epitaxy allows defect-free crystals to grow on substrates even with a large lattice mismatch. Furthermore, van der Waals epitaxy is proposed as a universal platform where heteroepitaxy can be achieved irrespective of the nature of the overlayer material and the method of crystallization. Here we demonstrate van der Waals epitaxy in solution phase synthesis for seedless and catalyst-free growth of ZnO wire arrays on phlogopite mica at low temperature. A unique incommensurate interface is observed even with the incomplete initial wetting of ZnO onto the substrate. Interestingly, the imperfect contacting layer does not affect the crystalline and optical properties of other parts of the wires. In addition, we present patterned growth of a well-ordered array with hexagonal facets and in-plane alignment. We expect our seedless and catalyst-free solution phase van der Waals epitaxy synthesis to be widely applicable in other materials and structures

  11. Numerical integration of nearly-Hamiltonian systems. [Van der Pol oscillator and perturbed Keplerian motion

    NASA Technical Reports Server (NTRS)

    Bond, V. R.

    1978-01-01

    The reported investigation is concerned with the solution of systems of differential equations which are derived from a Hamiltonian function in the extended phase space. The problem selected involves a one-dimensional perturbed harmonic oscillator. The van der Pol equation considered has an exact asymptotic value for its amplitude. Comparisons are made between a numerical solution and a known analytical solution. In addition to the van der Pol problem, known solutions regarding the restricted problem of three bodies are used as examples for perturbed Keplerian motion. The extended phase space Hamiltonian discussed by Stiefel and Scheifele (1971) is considered. A description is presented of two canonical formulations of the perturbed harmonic oscillator.

  12. Effect of van der Waals interaction on the mode I fracture characteristics of graphene sheet

    NASA Astrophysics Data System (ADS)

    Parashar, Avinash; Mertiny, Pierre

    2013-11-01

    In this paper a study has been performed to investigate the effect of van der Waals interaction forces on the mode I (opening mode) fracture characteristics of a graphene sheet. Finite element based atomistic approach was employed to perform the investigation, where graphene structure was assumed to behave like a space frame structure. Few graphene sheets were modeled in finite element environment with different set of interlayer spacing. Modified virtual crack closure technique (VCCT) was employed to estimate the strain energy release rate (SERR) under mode I of fracture criteria. Significant effect of van der Waals forces was observed on the mode I fracture characteristics of graphene.

  13. Replica-exchange method in van der Waals radius space: overcoming steric restrictions for biomolecules.

    PubMed

    Itoh, Satoru G; Okumura, Hisashi; Okamoto, Yuko

    2010-04-01

    We present a new type of the Hamiltonian replica-exchange method, where the van der Waals radius parameter and not the temperature is exchanged. By decreasing the van der Waals radii, which control spatial sizes of atoms, this Hamiltonian replica-exchange method overcomes the steric restrictions and energy barriers. Furthermore, the simulation based on this method escapes from the local-minimum free-energy states and realizes effective sampling in the conformational space. We applied this method to an alanine dipeptide in aqueous solution and showed the effectiveness of the method by comparing the results with those obtained from the conventional canonical and replica-exchange methods.

  14. [A case of lymphocyst infection caused by vanB type VRE].

    PubMed

    Imafuku, Y; Yoshida, H; Sato, T; Yamada, H; Sato, A; Hiramatsu, K

    1999-05-01

    A case of post-operative abdominal lymphocyst infection caused by vanB type vancomycin resistant enterococcus (VRE) in reported. A 27-year-old female was diagnosed as pregnancy with uterine cervical carcinoma and underwent Cesarean section and radical hysterectomy. After discharge, she developed a high fever which was diagnosed as a lymphocyst infection. Microbiological examination demonstrated the presence of vanB type VRE in the cyst fluid. Cyst cleaning and minocyclin injection were effective. This is the first case of VRE infection in Japan.

  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. [Legitimation of Andries Van Wesele, Andreas Vesalius's father, by the Holy Roman Emperor Charles the Fifth].

    PubMed

    Izumi, Hyonosuke

    2006-06-01

    Andries van Wesele, Andreas Vesalius's father and a court pharmacist of the Holy Roman Emperor Charles the fifth, was an illegitimate son of Everard van Wesele, a court physician of the Hapsburgs. In the year of 1531, Andries was legitimated by the Emperor. The legitimation letter was written in French. The author tried to translate and analyze the letter. By this legitimation, not only Andries himself was legitimated but also his successors were approved to succeed Andries. By this letter, Andreas Vesalius obtained his position as a hereditary member of a family serving the court of the Hapsburgs, and as a result, he started his career as a physician of the court.

  17. 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.

  18. 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…

  19. 77 FR 33491 - Phillips-Van Heusen Corporation, Izod Women's Wholesale Division, New York, NY; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-06

    ... published in the Federal Register on April 19, 2012 (77 FR 23511). The initial investigation resulted in a... Employment and Training Administration Phillips-Van Heusen Corporation, Izod Women's Wholesale Division, New... former workers of Phillips-Van Heusen Corporation, Izod Women's Wholesale Division, New York, New...

  20. What Gets Processed in Processing Instruction? A Commentary on Bill VanPatten's "Processing Instruction: An Update."

    ERIC Educational Resources Information Center

    DeKeyser, Robert; Salaberry, Rafael; Robinson, Peter; Harrington, Michael

    2002-01-01

    Responds to VanPatten's update of the findings for processing instruction. Questions the explanatory adequacy of the model of input processing that VanPatten proposed and that underpins his pedagogic proposals. Questions the validity of the limited-capacity, single-resource model of attention proposed for second language learning. (Author/VWL)

  1. Population structure and acquisition of the vanB resistance determinant in German clinical isolates of Enterococcus faecium ST192

    PubMed Central

    Bender, Jennifer K.; Kalmbach, Alexander; Fleige, Carola; Klare, Ingo; Fuchs, Stephan; Werner, Guido

    2016-01-01

    In the context of the global action plan to reduce the dissemination of antibiotic resistances it is of utmost importance to understand the population structure of resistant endemic bacterial lineages and to elucidate how bacteria acquire certain resistance determinants. Vancomycin resistant enterococci represent one such example of a prominent nosocomial pathogen on which nation-wide population analyses on prevalent lineages are scarce and data on how the bacteria acquire resistance, especially of the vanB genotype, are still under debate. With respect to Germany, an increased prevalence of VRE was noted in recent years. Here, invasive infections caused by sequence type ST192 VRE are often associated with the vanB-type resistance determinant. Hence, we analyzed 49 vanB-positive and vanB-negative E. faecium isolates by means of whole genome sequencing. Our studies revealed a distinct population structure and that spread of the Tn1549-vanB-type resistance involves exchange of large chromosomal fragments between vanB-positive and vanB-negative enterococci rather than independent acquisition events. In vitro filter-mating experiments support the hypothesis and suggest the presence of certain target sequences as a limiting factor for dissemination of the vanB element. Thus, the present study provides a better understanding of how enterococci emerge into successful multidrug-resistant nosocomial pathogens. PMID:26902259

  2. 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…

  3. On Attempting to Do What Lord Said Was Impossible: Commentary on van der Linden's "Some Conceptual Issues in Observed-Score Equating"

    ERIC Educational Resources Information Center

    Dorans, Neil J.

    2013-01-01

    van der Linden (this issue) uses words differently than Holland and Dorans. This difference in language usage is a source of some confusion in van der Linden's critique of what he calls equipercentile equating. I address these differences in language. van der Linden maintains that there are only two requirements for score equating. I maintain…

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

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Astronaut James D. van Hoften on the Discovery's remote manipulator system (RMS) visually tracking the Syncom IV-3 communications satellite after its second release. The satellite is partially visible at the edge of the frame. Clouds over the ocean form the backdrop.

  5. KITCHEN (NORTH WING), BRICK OVEN, WRITING ON DOOR “THE VAN ...

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

    KITCHEN (NORTH WING), BRICK OVEN, WRITING ON DOOR “THE VAN HOUTEN DOOR, SIZE 12 x 28, March 26, 95 (PAT), MANUFACTURED BY DUTCHESS TOOL CO., BEACON, N.Y - Ormond Hotel, 15 East Granada, Ormond Beach, Volusia County, FL

  6. Ellis-van Creveld syndrome: report of 15 cases in an inbred kindred.

    PubMed Central

    da Silva, E O; Janovitz, D; de Albuquerque, S C

    1980-01-01

    An inbred kindred with 15 cases of the autosomal recessive Ellis-van Creveld syndrome is reported. The ages of the 12 living affected varied between 3 and 82 years. The main characteristics include polydactyly of the hands and feet and several other skeletal anomalies, oral manifestations, and malformations of the heart in 50% of the living affected. Images PMID:7218275

  7. The Van Horn Engineering & Technology Magnet High School: 1990-1991. Formative Evaluation.

    ERIC Educational Resources Information Center

    Atwater, Jay, Ed.

    This report presents a formative evaluation of the Van Horn Engineering and Technology Magnet High School in the Kansas City School District, Missouri. It presents data collected throughout the program's first year, including student demographics, program implementation information, achievement data, and perceptions of the program held by staff…

  8. Generalized van der Waals Hamiltonian: periodic orbits and C1 nonintegrability.

    PubMed

    Guirao, Juan L G; Llibre, Jaume; Vera, Juan A

    2012-03-01

    The aim of this paper is to study the periodic orbits of the generalized van der Waals Hamiltonian system. The tool for studying such periodic orbits is the averaging theory. Moreover, for this Hamiltonian system we provide information on its C(1) nonintegrability, i.e., on the existence of a second first integral of class C(1).

  9. 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…

  10. Gas Temperature Determination in Argon-Helium Plasma at Atmospheric Pressure using van der Waals Broadening

    SciTech Connect

    Munoz, Jose; Yubero, Cristina; Calzada, Maria Dolores; Dimitrijevic, Milan S.

    2008-10-22

    The use of the van der Waals broadening of Ar atomic lines to determine the gas temperature in Ar-He plasmas, taking into account both argon and helium atoms as perturbers, has been analyzed. The values of the gas temperature inferred from this broadening have been compared with those obtained from the spectra of the OH molecular species in the discharge.

  11. Ecological mindfulness, spirituality, and life-long (hybrid, dialogical) learning: a tribute to Michiel van Eijck

    NASA Astrophysics Data System (ADS)

    Roth, Wolff-Michael

    2015-03-01

    In this tribute, I articulate the contributions Michiel van Eijck made to science education, as experienced through our relation, which ranged from supervisor and colleague to friend. His ecological thinking about human knowing, which was reflected in his spiritual inclinations, constitutes his legacy that will have an impact on our field for years to come.

  12. Maxwell's Relations for a van der Waals Gas and a Nuclear Paramagnetic System.

    ERIC Educational Resources Information Center

    Herlihy, James; And Others

    1981-01-01

    Since Maxwell's relations are derived in general form from the first to second laws, and students often wonder what they mean and how they are used, appropriate partition functions for van der Waals gas and the nuclear paramagnetic system are used to obtain entropy expressions and equations of state. (Author/SK)

  13. Generalized van der Waals theory for the thermodynamic properties of square-well fluids

    NASA Astrophysics Data System (ADS)

    Largo, J.; Solana, J. R.

    2003-06-01

    A theory previously developed for the coordination number of square-well fluids is used within the context of a generalized van der Waals theory to obtain the compressibility factor and the internal energy of these fluids. Results are compared with computer simulations for several densities, temperatures, and potential widths, which are also reported.

  14. The Reception of J. H. van't Hoff's Theory of the Asymmetric Carbon Atom

    ERIC Educational Resources Information Center

    Snelders, H. A. M.

    1974-01-01

    Discusses Jacobus Henricus van't Hoff's revolutionary theory of the asymmetric carbon atom and its early reception among his contemporaries in the Netherlands. Indicates that the extension of the new idea to practical problems gives the impetus to the development of stereochemistry. (CC)

  15. A simple van't Hoff law for calculating Langmuir constants in clathrate hydrates

    NASA Astrophysics Data System (ADS)

    Lakhlifi, Azzedine; Dahoo, Pierre Richard; Picaud, Sylvain; Mousis, Olivier

    2015-02-01

    This work gives a van't Hoff law expression of Langmuir constants of different species for determining their occupancy in clathrate hydrates. First, a pairwise site-site interaction potential energy model is used to calculate the Langmuir constants in an otherwise anisotropic potential environment, as a function of temperature. The results are then fitted to a van't Hoff law expression to give a set of parameters that can be used for calculating clathrates compositions. The van't Hoff law's parameters are given for eighteen gas species trapped in the small and large cavities of structure types I and II. The accuracy of this approach is based on a detailed comparison with available experimental and/or previously calculated data for ethane, cyclo-propane, methane and carbon dioxide clathrate hydrates. A comparison with the analytical cell method is also carried out to better understand the importance of asymmetry and possible limitations of the van't Hoff temperature dependence.

  16. 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…

  17. Using pedotransfer functions to estimate the van Genuchten-Mualem soil hydraulic properties: A review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this paper, we review the use of the van Genuchten Mualem (VGM) model to parameterize the soil moisture retention characteristic (MRC) and the nsaturated hydraulic conductivity curve (HCC), as well as its use in developing pedotransfer functions (PFTs). Analysis of literature data showed that MRC...

  18. Ecological Mindfulness, Spirituality, and Life-Long (Hybrid, Dialogical) Learning: A Tribute to Michiel Van Eijck

    ERIC Educational Resources Information Center

    Roth, Wolff-Michael

    2015-01-01

    In this tribute, I articulate the contributions Michiel van Eijck made to science education, as experienced through our relation, which ranged from supervisor and colleague to friend. His ecological thinking about human knowing, which was reflected in his spiritual inclinations, constitutes his legacy that will have an impact on our field for…

  19. van der Waals Density Functional Theory vdW-DFq for Semihard Materials

    NASA Astrophysics Data System (ADS)

    Peng, Qing; de, Suvranu

    There are a large number of materials with mild stiffness, which are not as soft as tissues and not as strong as metals. These semihard materials includes energetic materials, molecular crystals, layered materials, and van der Waals crystals. The integrity and mechanical stability are mainly determined by the interactions between instantaneously induced dipoles, the so called London dispersion force or van der Waals force. It is challenging to accurately model the structural and mechanical properties of these semihard materials in the frame of density functional theory where the non-local correlation functionals are not well known. Here we propose a van der Waals density functional named vdW-DFq to accurately model the density and geometry of semihard materials. Using β-cyclotetramethylene tetranitramine as a prototype, we adjust the enhancement factor of the exchange energy functional with generalized gradient approximations. We find this method to be simple and robust over a wide tuning range when calibrating the functional on-demand with experimental data. With a calibrated value q = 1 . 05 , the proposed vdW-DFq method shows good performance in predicting the geometries of 11 common energetic material molecular crystals and 3 typical layered van der Waals crystals. The authors would like to acknowledge the generous financial support from the Defense Threat Reduction Agency (DTRA) Grant # HDTRA1-13-1-0025.

  20. 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…

  1. Approximating the 3D Character of a Van Der Waals Atom-Solid Potential

    NASA Astrophysics Data System (ADS)

    Bruch, L. W.

    2016-10-01

    A truncated Fourier decomposition of the atom-substrate potential energy is developed for three-dimensional models of van der Waals systems, specifically for adsorption on the basal plane surface of graphite or the (111) face of a face-centered-cubic lattice. This provides a framework for analysis of a priori calculations of physical adsorption energies.

  2. The Legacy of Miriam Van Waters: The Warden Who Would Be Their Teacher First

    ERIC Educational Resources Information Center

    Chlup, Dominique T.

    2006-01-01

    Dr. Miriam Van Waters was the superintendent (warden) of the Massachusetts Reformatory for Women at Framingham for twenty-five years. She has the distinct honor of holding that position the longest. In 1949, she rose to national prominence when the new Massachusetts Commissioner of Corrections, under allegations of lax administrative policies,…

  3. The first record of Pyxidium tardigradum Van der Land, 1964 (Ciliophora) in Romania.

    PubMed

    Ciobanu, Daniel Adrian; Roszkowska, Milena; Moglan, Ioan; Kaczmarek, Łukasz

    2015-04-02

    In three lichen samples collected from eastern part of Romania, three populations of Ramazzottius cf. oberhaeuseri (Doyère, 1840) infested by Pyxidium tardigradum Van der Land 1964 were found. In this short correspondence we present a first record of P. tardigradum in Romania and infestation rates in studied populations according to the different life stages.

  4. Mt. Druitt Early Childhood Project. Third, Fourth, and Fifth Annual Reports to Bernard Van Leer Foundation.

    ERIC Educational Resources Information Center

    Macquarie Univ., North Ryde (Australia). School of Education.

    This series of the third, fourth, and fifth annual reports to the Bernard Van Leer Foundation on the Mt. Druitt Early Childhood Project of Macquarie University, Australia, describes the general activities, program developments, and research activities of the project for the period 1977-1979. The main objective of the project is to develop,…

  5. 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…

  6. 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…

  7. Cross-Racial Voicing: Carl Van Vechten's Imagination and the Search for an African American Ethos

    ERIC Educational Resources Information Center

    Holmes, David G.

    2006-01-01

    The author uses a discussion of Van Vechten's "Nigger Heaven" to argue that cross-racial voicing on the part of white writers may in fact express an attempt to acknowledge and perhaps explore the rhetorical efficacy of a black ethos. He also suggests that English studies scholars of all races need to create forums where cross-racial voicing can be…

  8. First principles calculations of solid-state thermionic transport in layered van der Waals heterostructures.

    PubMed

    Wang, Xiaoming; Zebarjadi, Mona; Esfarjani, Keivan

    2016-08-21

    This work aims at understanding solid-state energy conversion and transport in layered (van der Waals) heterostructures in contact with metallic electrodes via a first-principles approach. As an illustration, a graphene/phosphorene/graphene heterostructure in contact with gold electrodes is studied by using density functional theory (DFT)-based first principles calculations combined with real space Green's function (GF) formalism. We show that for a monolayer phosphorene, quantum tunneling dominates the transport. By adding more phosphorene layers, one can switch from tunneling-dominated transport to thermionic-dominated transport, resulting in transporting more heat per charge carrier, thus, enhancing the cooling coefficient of performance. The use of layered van der Waals heterostructures has two advantages: (a) thermionic transport barriers can be tuned by changing the number of layers, and (b) thermal conductance across these non-covalent structures is very weak. The phonon thermal conductance of the present van der Waals heterostructure is found to be 4.1 MW m(-2) K(-1) which is one order of magnitude lower than the lowest value for that of covalently-bonded interfaces. The thermionic coefficient of performance for the proposed device is 18.5 at 600 K corresponding to an equivalent ZT of 0.13, which is significant for nanoscale devices. This study shows that layered van der Waals structures have great potential to be used as solid-state energy-conversion devices.

  9. 49 CFR 523.7 - Heavy-duty pickup trucks and vans.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 523.7 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.7 Heavy-duty pickup... engines manufactured for use in heavy-duty pickup trucks or vans. See references in 40 CFR 1037.104 and...

  10. First principles calculations of solid-state thermionic transport in layered van der Waals heterostructures.

    PubMed

    Wang, Xiaoming; Zebarjadi, Mona; Esfarjani, Keivan

    2016-08-21

    This work aims at understanding solid-state energy conversion and transport in layered (van der Waals) heterostructures in contact with metallic electrodes via a first-principles approach. As an illustration, a graphene/phosphorene/graphene heterostructure in contact with gold electrodes is studied by using density functional theory (DFT)-based first principles calculations combined with real space Green's function (GF) formalism. We show that for a monolayer phosphorene, quantum tunneling dominates the transport. By adding more phosphorene layers, one can switch from tunneling-dominated transport to thermionic-dominated transport, resulting in transporting more heat per charge carrier, thus, enhancing the cooling coefficient of performance. The use of layered van der Waals heterostructures has two advantages: (a) thermionic transport barriers can be tuned by changing the number of layers, and (b) thermal conductance across these non-covalent structures is very weak. The phonon thermal conductance of the present van der Waals heterostructure is found to be 4.1 MW m(-2) K(-1) which is one order of magnitude lower than the lowest value for that of covalently-bonded interfaces. The thermionic coefficient of performance for the proposed device is 18.5 at 600 K corresponding to an equivalent ZT of 0.13, which is significant for nanoscale devices. This study shows that layered van der Waals structures have great potential to be used as solid-state energy-conversion devices. PMID:27314610

  11. The Wim Van Leer Competition for Young Film Makers at the Jerusalem Film Festival.

    ERIC Educational Resources Information Center

    Mendel, Gilli

    1999-01-01

    Describes the Jerusalem Film Center and the background, history, and organization of the Wim Van Leer Competition which was established for young filmmakers in high school. Describes the Jerusalem Film Festival, film studies programs at Israeli high schools, and future possibilities. (Author/LRW)

  12. 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) "Fathers Matter…

  13. Comments on "Some Conceptual Issues in Observed-Score Equating" by Wim J. van der Linden

    ERIC Educational Resources Information Center

    Bradlow, Eric T.

    2013-01-01

    The van der Linden article (this issue) provides a roadmap for future research in equating. My belief is that the roadmap begins and ends with collecting auxiliary data that can be utilized to provide improved equating, especially when data are sparse or equating beyond simple moments is desired.

  14. The Average IQ of Sub-Saharan Africans: Comments on Wicherts, Dolan, and van der Maas

    ERIC Educational Resources Information Center

    Lynn, Richard; Meisenberg, Gerhard

    2010-01-01

    Wicherts, Dolan, and van der Maas (2009) contend that the average IQ of sub-Saharan Africans is about 80. A critical evaluation of the studies presented by WDM shows that many of these are based on unrepresentative elite samples. We show that studies of 29 acceptably representative samples on tests other than the Progressive Matrices give a…

  15. 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.

  16. First kind symmetric periodic solutions of the generalized van der Waals Hamiltonian

    NASA Astrophysics Data System (ADS)

    Alberti, Angelo; Vidal, Claudio

    2016-07-01

    The aim of this paper is to prove the existence of a new symmetric family of periodic solutions of the generalized van der Waals Hamiltonian. In fact, we prove the existence of several families of first kind symmetric periodic solutions as continuation of circular orbits of the Kepler problem in the spatial case.

  17. Goiter in paintings by Rogier van der Weyden (1399-1464).

    PubMed

    Lazzeri, Davide; Pozzilli, Paolo; Zhang, Yi Xin; Persichetti, Paolo

    2015-05-01

    Figures affected by goiter were only sparsely depicted by Peter Paul Rubens and Albrecht Dürer among Flemish artists, because obvious goiter was not common in regions such as the Netherlands and Belgium. However, the recent observation of two figures with a goiter elegantly depicted by Rogier van der Weyden has raised our interest in this topic. When taking a close look at the paintings of this Flemish Renaissance painter, it is interesting to note that 16 portrayed subjects show an abnormal profile of the neck with swelling, suggestive of a presumptive medico-artistic diagnosis of goiter. Van der Weyden travelled to Italy where he soon acquired great fame and was second only to the other Flemish painter of the time, Jan Van Eyck. It is very likely that in Italy he had the opportunity to look at several female figures depicted with goiter, which may have influenced his paintings. Van der Weyden was appreciated because of his style to mix realistic details with idealized softened features to increase the beauty and appeal of his models. It is also likely that the integration of the goiter may have been part of the Renaissance tendency toward a more realistic and precise representation of subjects. The fact that in almost all cases the goiter was a low-to-moderate grade enlargement of the thyroid may confirm our speculation that perhaps the painter used the same model or the template derived from one model for subsequent paintings. PMID:25747746

  18. An Interview with Dr. Roach van Allen (Leaders in Reading Research and Instruction).

    ERIC Educational Resources Information Center

    Searfoss, Lyndon; Jerrolds, Bob W.

    1989-01-01

    Presents an interview with Dr. Roach van Allen in which he describes how he became involved in education, who influenced him professionally, his proudest accomplishments (a theoretical model for a language experience program), what he sees as the current problems in reading education, and what he sees in the future. (RS)

  19. An Instrument for Measuring Performance in Geometry Based on the Van Hiele Model

    ERIC Educational Resources Information Center

    Sánchez-García, Ana B.; Cabello, Ana Belén

    2016-01-01

    In this paper we present the process of constructing a test for assessing student performance in geometry corresponding to the first year of Secondary Education. The main goal was to detect student errors in the understanding of geometry in order to develop a proposal according to the Van Hiele teaching model, explained in this paper. Our research…

  20. Precipitation of relativistic electrons of the Van Allen belts into the proton aurora

    SciTech Connect

    Jordanova, Vania K; Miyoshi, Y; Sakaguchi, K; Shiokawa, K; Evans, D S; Connors, M

    2008-01-01

    The Van Allen electron belts consist of two regions encircling the earth in which relativistic electrons are trapped in the earth's magnetic field. Populations of relativistic electrons in the Van Allen belts vary greatly with geomagnetic disturbance and they are a major source of damage to space vehicles. In order to know when and by how much these populations of relativistic electrons increase, it is important to elucidate not only the cause of acceleration of relativistic electrons but also the cause of their loss from the Van Allen belts. Here we show the first evidence that left-hand polarized electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere, on the basis of results of an excellent set of ground and satellite observations showing coincident precipitation of ions with energies of tens of keV and of relativistic electrons into an isolated proton aurora. The proton aurora was produced by precipitation of ions with energies of tens of keV due to EMIC waves near the plasma pause, which is a manifestation of wave-particle interactions. These observations clarify that ions with energies of tens of keV affect the evolution of relativistic electrons in the Van Allen belts via parasitic resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970's.

  1. 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.

  2. 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.

  3. Description of a new species of Pseudomegischus van Achterberg from China (Hymenoptera, Stephanidae)

    PubMed Central

    Chen, Hua-yan; Hong, Chun-dan; van Achterberg, Cornelis; Xu, Zai-fu

    2016-01-01

    Abstract A new species of the genus Pseudomegischus van Achterberg, Pseudomegischus yunnanensis sp. n., is described and illustrated from Yunnan Province, China. This is the second species of the genus reported from China. A modified section of the identification key to species of Pseudomegischus is added to include the new species. PMID:27551191

  4. 77 FR 66493 - Van Eck Funds, et al.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-05

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Van Eck Funds, et al.; Notice of Application October 25, 2012. AGENCY: Securities and Exchange Commission (``Commission''). ACTION: Notice of application for an order under section 17(d) of the...

  5. Dynamics of Gold Nanoparticles on Carbon Nanostructures Driven by van der Waals and Electrostatic Interactions.

    PubMed

    La Torre, Alessandro; Gimenez-Lopez, Maria del Carmen; Fay, Michael W; Lucas, Carlos Herreros; Brown, Paul D; Khlobystov, Andrei N

    2015-06-01

    Transmission electron microscopy studies on the assembly and growth of gold nanoparticles on carbon nanotubes supported on few-layer graphene and amorphous carbon reveal a competition between van der Waals forces and electrostatic interactions, enabling controlled positioning and sizing of adsorbed nanoparticles at the nanochannels formed between the carbon nanotube and the few-layer graph-ene surface. PMID:25689488

  6. Goiter in paintings by Rogier van der Weyden (1399-1464).

    PubMed

    Lazzeri, Davide; Pozzilli, Paolo; Zhang, Yi Xin; Persichetti, Paolo

    2015-05-01

    Figures affected by goiter were only sparsely depicted by Peter Paul Rubens and Albrecht Dürer among Flemish artists, because obvious goiter was not common in regions such as the Netherlands and Belgium. However, the recent observation of two figures with a goiter elegantly depicted by Rogier van der Weyden has raised our interest in this topic. When taking a close look at the paintings of this Flemish Renaissance painter, it is interesting to note that 16 portrayed subjects show an abnormal profile of the neck with swelling, suggestive of a presumptive medico-artistic diagnosis of goiter. Van der Weyden travelled to Italy where he soon acquired great fame and was second only to the other Flemish painter of the time, Jan Van Eyck. It is very likely that in Italy he had the opportunity to look at several female figures depicted with goiter, which may have influenced his paintings. Van der Weyden was appreciated because of his style to mix realistic details with idealized softened features to increase the beauty and appeal of his models. It is also likely that the integration of the goiter may have been part of the Renaissance tendency toward a more realistic and precise representation of subjects. The fact that in almost all cases the goiter was a low-to-moderate grade enlargement of the thyroid may confirm our speculation that perhaps the painter used the same model or the template derived from one model for subsequent paintings.

  7. A van der Waals Equation of State for a Dilute Boson Gas

    ERIC Educational Resources Information Center

    Deeney, F. A.; O'Leary, J. P.

    2012-01-01

    An equation of state of a system is a relationship that connects the thermodynamic variables of the system such as pressure and temperature. Such equations are well known for classical gases but less so for quantum systems. In this paper we develop a van der Waals equation of state for a dilute boson gas that may be used to explain the occurrence…

  8. Bonded Paths and van der Waals Interactions in Orpiment, As2S3

    SciTech Connect

    Gibbs, Gerald V.; Wallace, Adam F.; Zallen, Richard; Downs, R. T.; Ross, Nancy L.; Cox, David F.; Rosso, Kevin M.

    2010-06-17

    Bond critical properties and bond paths have been calculated for the thioarsenide molecular crystal orpiment, As2S3. In addition to the intramolecular As-S bond paths and van der Waals As-S and S-S bond paths within the layers, intermolecular S-S, As-S and As-As van der Waals paths exist between the layers. The S-S bond paths between the layers are identified with the main interlayer restoring forces responsible for the vibrational internal-mode splitting and the low frequency rigid layer modes previously documented in infrared and Raman studies of orpiment. These S-S bond paths are comparable with those calculated for orthorhombic native sulfur and the As4Sn (n = 3,4,5) molecules for several arsenide molecular crystals. The As-S bond paths show that the two nonequivalent arsenic atoms are each coordinated by a highly distorted octahedral array of sulfur atoms. The octahedra consist of three As-S intramolecular bonded interactions and three longer van der Waals interactions (two intramolecular and one intermolecular). One of the arsenic atoms is also coordinated by an arsenic atom in an interlayer As-As bonded interaction. Laplacian isosurface envelopes calculated for the arsenic and sulfur atoms are comparable with those calculated for native arsenic and orthorhombic sulfur. The intermolecular As-S bond paths connect Lewis acid domains on arsenic and an Lewis base domains on sulfur. Van der Waals interactions are traditionally defined as attractive interactions other than those ascribed to bond formation. However, theoretical evidence and arguments, as well as the connection between the bond paths and the vibrational spectra, indicate that the van der Waals interactions in orpiment are directed bonded interactions in the Slater sense. The experimental bond lengths for the As-S and S-S bonded interactions decrease nonlinearly with the increasing value of the electron density at the bond critical point, concomitant with a decrease in the bonded radii of arsenic and

  9. Discrete characteristics of the aftershock sequence of the 2011 Van earthquake

    NASA Astrophysics Data System (ADS)

    Toker, Mustafa

    2014-10-01

    An intraplate earthquake of magnitude Mw 7.2 occurred on a NE-SW trending blind oblique thrust fault in accretionary orogen, the Van region of Eastern Anatolia on October 23, 2011. The aftershock seismicity in the Van earthquake was not continuous but, rather, highly discrete. This shed light on the chaotic nonuniformity of the event distribution and played key roles in determining the seismic coupling between the rupturing process and seismogeneity. I analyzed the discrete statistical mechanics of the 2011 Van mainshock-aftershock sequence with an estimation of the non-dimensional tuning parameters consisting of; temporal clusters (C) and the random (RN) distribution of aftershocks, range of size scales (ROSS), strength change (εD), temperature (T), P-value of temporal decay, material parameter R-value, seismic coupling χ, and Q-value of aftershock distribution. I also investigated the frequency-size (FS), temporal (T) statistics and the sequential characteristics of aftershock dynamics using discrete approach and examined the discrete evolutionary periods of the Van earthquake Gutenberg-Richter (GR) distribution. My study revealed that the FS and T statistical properties of aftershock sequence represent the Gutenberg-Richter (GR) distribution, clustered (C) in time and random (RN) Poisson distribution, respectively. The overall statistical behavior of the aftershock sequence shows that the Van earthquake originated in a discrete structural framework with high seismic coupling under highly variable faulting conditions. My analyses relate this larger dip-slip event to a discrete seismogenesis with two main components of complex fracturing and branching framework of the ruptured fault and dynamic strengthening and hardening behavior of the earthquake. The results indicate two dynamic cases. The first is associated with aperiodic nature of aftershock distribution, indicating a time-independent Poissonian event. The second is associated with variable slip model

  10. 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

  11. Functional relationships for the estimation of van Genuchten parameter values in landfill processes models.

    PubMed

    White, Jim; Zardava, Kiriaki; Nayagum, Dharumarajen; Powrie, William

    2015-04-01

    Numerical models of landfill processes need to be able to estimate the capillary pressure and relative permeability of waste as a function of moisture content using analytical equations such as the van Genuchten equations. The paper identifies the range of van Genuchten parameter values for use in models and proposes a formulaic relationship between these parameter values and saturated moisture content. The concept of porous material, its behaviour under unsaturated conditions and Mualem's integral transform equation that estimates relative permeability from capillary pressure are reviewed. The application of the algebraic form of the capillary pressure function proposed by van Genuchten and its application using Mualem's transform to obtain the van Genuchten algebraic functions for relative permeability are discussed. Functional relationships are identified between saturated moisture content and the van Genuchten parameters using a database of results from other sources. These relationships may be used in numerical modelling of unsaturated flow in landfilled waste where the saturated moisture content varies significantly as the result of compression, settlement and degradation. A 2D numerical model simulation of leachate recirculation is used to investigate the sensitivity of the simulation to the introduction of these functional relationships. It is found that the transient liquid and gas flows across the model boundaries appear to be insensitive to whether or not the functions are incorporated into the model algorithm. However it is observed that using the relationships does have some impact on the distribution of the degree of saturation throughout the model and on the transient behaviour of the way in which the recirculation recharges the waste. However it is not thought that this impact would be sufficient to influence the design of a leachate recirculation system.

  12. Functional relationships for the estimation of van Genuchten parameter values in landfill processes models.

    PubMed

    White, Jim; Zardava, Kiriaki; Nayagum, Dharumarajen; Powrie, William

    2015-04-01

    Numerical models of landfill processes need to be able to estimate the capillary pressure and relative permeability of waste as a function of moisture content using analytical equations such as the van Genuchten equations. The paper identifies the range of van Genuchten parameter values for use in models and proposes a formulaic relationship between these parameter values and saturated moisture content. The concept of porous material, its behaviour under unsaturated conditions and Mualem's integral transform equation that estimates relative permeability from capillary pressure are reviewed. The application of the algebraic form of the capillary pressure function proposed by van Genuchten and its application using Mualem's transform to obtain the van Genuchten algebraic functions for relative permeability are discussed. Functional relationships are identified between saturated moisture content and the van Genuchten parameters using a database of results from other sources. These relationships may be used in numerical modelling of unsaturated flow in landfilled waste where the saturated moisture content varies significantly as the result of compression, settlement and degradation. A 2D numerical model simulation of leachate recirculation is used to investigate the sensitivity of the simulation to the introduction of these functional relationships. It is found that the transient liquid and gas flows across the model boundaries appear to be insensitive to whether or not the functions are incorporated into the model algorithm. However it is observed that using the relationships does have some impact on the distribution of the degree of saturation throughout the model and on the transient behaviour of the way in which the recirculation recharges the waste. However it is not thought that this impact would be sufficient to influence the design of a leachate recirculation system. PMID:25573738

  13. Improved Detection of vanB2-Containing Enterococcus faecium with Vancomycin Susceptibility by Etest Using Oxgall Supplementation▿

    PubMed Central

    Grabsch, E. A.; Chua, K.; Xie, S.; Byrne, J.; Ballard, S. A.; Ward, P. B.; Grayson, M. L.

    2008-01-01

    We have isolated a number of vanB-containing Enterococcus faecium isolates on bile esculin screening agar containing 6 mg/liter vancomycin, which on subsequent susceptibility testing using Etest have repeatedly demonstrated vancomycin MICs of ≤4 mg/liter. To investigate this genotype-phenotype incongruence of “low-MIC vancomycin-resistant enterococci” (LM-VRE), we examined the molecular characteristics of these isolates, including the presence of the vanB operon, using PCR amplification and DNA sequencing. All LM-VRE isolates contained vanB associated with the transposon Tn1549 and were polyclonal. Sequencing of the vanB ligase gene showed no differences from the prototype vanB2. In addition, we examined supplemented media to improve phenotypic detection of these isolates. Etest detection of LM-VRE improved when Mueller-Hinton agar (MHA) and brain heart infusion agar (BHIA) were supplemented with 10 g/liter oxgall (MHA-Oxg and BHIA-Oxg, respectively). We assessed the sensitivity and specificity of these media to detect vancomycin resistance using vancomycin-resistant vanB-containing E. faecium (n = 11), vancomycin-susceptible (van negative) E. faecium (n = 11), vancomycin-susceptible (van negative) E. faecalis (n = 11), and our LM-VRE (n = 23) isolates. After 48 h of incubation, both MHA-Oxg and BHIA-Oxg were 100% (34/34) sensitive and 100% (22/22) specific in the identification of vancomycin resistance. These findings suggest that supplementation of MHA or BHIA with 10 g/liter oxgall should be considered in laboratories where VRE detection protocols rely primarily on strain phenotype rather than early vanB gene detection by PCR. PMID:18434564

  14. In-situ epitaxial growth of graphene/h-BN van der Waals heterostructures by molecular beam epitaxy.

    PubMed

    Zuo, Zheng; Xu, Zhongguang; Zheng, Renjing; Khanaki, Alireza; Zheng, Jian-Guo; Liu, Jianlin

    2015-01-01

    Van der Waals materials have received a great deal of attention for their exceptional layered structures and exotic properties, which can open up various device applications in nanoelectronics. However, in situ epitaxial growth of dissimilar van der Waals materials remains challenging. Here we demonstrate a solution for fabricating van der Waals heterostructures. Graphene/hexagonal boron nitride (h-BN) heterostructures were synthesized on cobalt substrates by using molecular beam epitaxy. Various characterizations were carried out to evaluate the heterostructures. Wafer-scale heterostructures consisting of single-layer/bilayer graphene and multilayer h-BN were achieved. The mismatch angle between graphene and h-BN is below 1°.

  15. vanG element insertions within a conserved chromosomal site conferring vancomycin resistance to Streptococcus agalactiae and Streptococcus anginosus.

    PubMed

    Srinivasan, Velusamy; Metcalf, Benjamin J; Knipe, Kristen M; Ouattara, Mahamoudou; McGee, Lesley; Shewmaker, Patricia L; Glennen, Anita; Nichols, Megin; Harris, Carol; Brimmage, Mary; Ostrowsky, Belinda; Park, Connie J; Schrag, Stephanie J; Frace, Michael A; Sammons, Scott A; Beall, Bernard

    2014-01-01

    Three vancomycin-resistant streptococcal strains carrying vanG elements (two invasive Streptococcus agalactiae isolates [GBS-NY and GBS-NM, both serotype II and multilocus sequence type 22] and one Streptococcus anginosus [Sa]) were examined. The 45,585-bp elements found within Sa and GBS-NY were nearly identical (together designated vanG-1) and shared near-identity over an ~15-kb overlap with a previously described vanG element from Enterococcus faecalis. Unexpectedly, vanG-1 shared much less homology with the 49,321-bp vanG-2 element from GBS-NM, with widely different levels (50% to 99%) of sequence identity shared among 44 related open reading frames. Immediately adjacent to both vanG-1 and vanG-2 were 44,670-bp and 44,680-bp integrative conjugative element (ICE)-like sequences, designated ICE-r, that were nearly identical in the two group B streptococcal (GBS) strains. The dual vanG and ICE-r elements from both GBS strains were inserted at the same position, between bases 1328 and 1329, within the identical RNA methyltransferase (rumA) genes. A GenBank search revealed that although most GBS strains contained insertions within this specific site, only sequence type 22 (ST22) GBS strains contained highly related ICE-r derivatives. The vanG-1 element in Sa was also inserted within this position corresponding to its rumA homolog adjacent to an ICE-r derivative. vanG-1 insertions were previously reported within the same relative position in the E. faecalis rumA homolog. An ICE-r sequence perfectly conserved with respect to its counterpart in GBS-NY was apparent within the same site of the rumA homolog of a Streptococcus dysgalactiae subsp. equisimilis strain. Additionally, homologous vanG-like elements within the conserved rumA target site were evident in Roseburia intestinalis. Importance: These three streptococcal strains represent the first known vancomycin-resistant strains of their species. The collective observations made from these strains reveal a specific

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

    PubMed Central

    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

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

    PubMed Central

    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

  18. Evaluation of the iNtRON VRE vanA/vanB Real-Time PCR Assay for Detection of Vancomycin-Resistant Enterococci

    PubMed Central

    Huh, Hee Jae; Jang, Mi-Ae; Seo, Ja Young; Kim, Ji-Youn; Kim, Jong-Won; Lee, Nam Yong

    2015-01-01

    Background Recently, the iNtRON VRE vanA/vanB real-time PCR (iNtRON; iNtRON Biotechnology, Korea) assay, a multiplex real-time PCR method, was introduced. In this prospective study, we compared the iNtRON assay with the Seeplex VRE ACE detection kit (Seeplex; Seegene, Korea), a conventional multiplex PCR assay. Methods A chromogenic agar-based culture, in which pre-selected vancomycin-resistant enterococci (VRE) was grown and subsequently plated on blood agar with vancomycin disks, was regarded as the reference method. A total of 304 consecutive rectal swab specimens were tested for VRE by culture and by iNtRON and Seeplex PCR assays. For the PCR assays, specimens were enriched for 16-24 hr before PCR. Results VRE were isolated from 44 (14.5%) specimens by chromogenic agar-based culture. The clinical sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the iNtRON assay were 100% (95% confidence interval: 89.8%-100%), 99.2% (96.9%-99.9%), 95.6% (83.6%-99.2%), and 100% (98.2%-100%), respectively, while those of the Seeplex assay were 97.7% (86.2%-99.9%), 99.6% (97.5%-99.9%), 97.7% (86.2%-99.9%), and 99.6% (97.5%-99.9%), respectively. The iNtRON assay had a detection limit of 3,159 copies/µL and 13,702 copies/µL for the vanA and vanB genes, respectively. No cross-reactivity was observed in 11 non-VRE bacterial culture isolates. Conclusions The overall performance of the iNtRON assay was comparable to that of a chromogenic agar-based culture method for prompt identification of VRE-colonized patients in hospitals. This assay could be an alternative or supportive method for the effective control of nosocomial VRE infection. PMID:25553284

  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. 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

  1. Binding and Diffusion of Lithium in Graphite: Quantum Monte Carlo Benchmarks and Validation of van der Waals Density Functional Methods.

    PubMed

    Ganesh, P; Kim, Jeongnim; Park, Changwon; Yoon, Mina; Reboredo, Fernando A; Kent, Paul R C

    2014-12-01

    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. 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 on point charges such as DFT-D are inaccurate unless the local charge transfer is assessed. The 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. PMID:26583215

  2. 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; Yoon, Mina; Reboredo, Fernando A.; Kent, Paul R. C.

    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 on 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.

  3. Binding and Diffusion of Lithium in Graphite: Quantum Monte Carlo Benchmarks and Validation of van der Waals Density Functional Methods.

    PubMed

    Ganesh, P; Kim, Jeongnim; Park, Changwon; Yoon, Mina; Reboredo, Fernando A; Kent, Paul R C

    2014-12-01

    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. 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 on point charges such as DFT-D are inaccurate unless the local charge transfer is assessed. The 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.

  4. Ford Van Dyke: Compressed Air Management Program Leads to Improvements that Reduce Energy Consumption at an Automotive Transmission Plant

    SciTech Connect

    2010-06-25

    Staff at the Ford Van Dyke Transmission Plant in Sterling Heights, Michigan, have increased the efficiency of the plant’s compressed air system to enhance its performance while saving energy and improving production.

  5. Coexisting two canards and their breakdown into chaos in the van der Pol oscillator under weak periodic perturbation

    NASA Astrophysics Data System (ADS)

    Sekikawa, Munehisa; Inaba, Naohiko; Aihara, Kazuyuki

    2007-04-01

    Two coexisting stable canards are discussed in a periodically driven singularly perturbed van der Pol equation, where the amplitude of the driving force is extremely small. Canard breakdown into chaos via period-doubling bifurcations is also observed.

  6. Historical case: "Portrait of a one-eyed man" by Vincent Van Gogh.

    PubMed

    Meulemans, J; Huskens, I; Piessens, P

    2014-01-01

    The post-impressionist Dutch painter Vincent Willem Van Gogh (1853-1890) painted the "Portrait of a one-eyed man" (1889) when he was admitted to the mental hospital of Saint Paul-de-Mausole. The portrait probably depicts one of Van Gogh's fellow patients who was suffering from a left-sided upper eyelid ptosis. Neurofibromatosis type I with orbitotemporal involvement has been suggested as the underlying disease process. However, from an otorhinolaryngological point of view, alternative diagnoses are possible. In this paper, the entities of giant frontal sinus osteoma and giant frontal sinus mucocoele are discussed, as well as the operative procedures available at the end of the nineteenth century to treat these lesions.

  7. [Growth, orthodontics and orthopedics, by Pierre Fauchard (1928), Hendrik Van Deventer (1739) and Nicolas Andry (1740)].

    PubMed

    Gysel, C

    1977-01-01

    In the eightteenth century (by Fauchard) and orthopaedics (by H. Van Deventer, a Dutch surgeon) have been founded independently as practcal sciences without the faculties of medicine. The famous book of Andry, "L'orthopédie", also translated in English (1743), has not been written for the medical profession. It deals only with "such means as may easily be put in practice by Parents themselves, and all such as are employed in Educating children". Nevertheless it states precisely the name of the speciality and defines some ethical, aesthetical and physiological principles also applicable to orthodontics. This is also the case for H. Van Deventer, who was the first to take plaster casts before, during and after treatment.

  8. Universal curves for the van der Waals interaction between single-walled carbon nanotubes.

    PubMed

    Pogorelov, Evgeny G; Zhbanov, Alexander I; Chang, Yia-Chung; Yang, Sung

    2012-01-17

    We report very simple and accurate algebraic expressions for the van der Waals (VDW) potentials and the forces between two parallel and crossed carbon nanotubes. The Lennard-Jones potential for two carbon atoms and the method of the smeared-out approximation suggested by Girifalco were used. It is found that the interaction between parallel and crossed tubes is described by two universal curves for parallel and crossed configurations that do not depend on the van der Waals constants, the angle between tubes, and the surface density of atoms and their nature but only on the dimensionless distance. The explicit functions for equilibrium VDW distances, well depths, and maximal attractive forces have been given. These results may be used as a guide for the analysis of experimental data to investigate the interaction between nanotubes of various natures. PMID:22129302

  9. Van der Waals heterostructure of phosphorene and hexagonal boron nitride: First-principles modeling

    NASA Astrophysics Data System (ADS)

    Peng, Zhang; Jing, Wang; Xiang-Mei, Duan

    2016-03-01

    We have studied the structural and electronic properties of a hybrid hexagonal boron nitride with phosphorene nanocomposite using ab initio density functional calculations. It is found that the interaction between the hexagonal boron nitride and phosphorene is dominated by the weak van der Waals interaction, with their own intrinsic electronic properties preserved. Furthermore, the band gap of the nanocomposite is dependent on the interfacial distance. Our results could shed light on the design of new devices based on van der Waals heterostructure. Projected supported by the National Natural Science Foundation of China (Grant No. 11574167), the New Century 151 Talents Project of Zhejiang Province,China, and the K. C. Wong Magna Foundation in Ningbo University, China.

  10. Selectively enhanced photocurrent generation in twisted bilayer graphene with van Hove singularity.

    PubMed

    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.

  11. Electrical and optical properties of SnS2/WSe2 van der Waals Heterojunction FETs

    NASA Astrophysics Data System (ADS)

    Zubair, Ahmad; Nourbakhsh, Amirhasan; Dresselhaus, Mildred; Palacios, Tomas

    Two dimensional crystals based on atomically thin films of transition metal dichalcogenides offer an exciting platform for various optoelectronic applications. Their unique crystal properties make them particularly attractive for van der Waals heterostructures which open up an additional degree of freedom to tailor the material properties into new physics and device applications. In this work, we explore, for the first time, the optoelectronic properties of van der Waals SnS2/WSe2 heterojunction. WSe2 is an ambipolar semiconductor while SnS2 is an n-type wide bandgap semiconductor. We use the pickup and dry transfer methods to fabricate SnS2/WSe2 heterojunction transistors (hetero-FETs). We observe negative differential transconductance in the SnS2/WSe2 hetero-FET. Also, the heterostructure couples strongly to incident light and shows high photovoltaic responsivity which can find applications in nano-devices such as photo-detectors and solar cells.

  12. Van der Waals force: a dominant factor for reactivity of graphene.

    PubMed

    Lee, Jong Hak; Avsar, Ahmet; Jung, Jeil; Tan, Jun You; Watanabe, K; Taniguchi, T; Natarajan, Srinivasan; Eda, Goki; Adam, Shaffique; Castro Neto, Antonio H; Özyilmaz, Barbaros

    2015-01-14

    Reactivity control of graphene is an important issue because chemical functionalization can modulate graphene's unique mechanical, optical, and electronic properties. Using systematic optical studies, we demonstrate that van der Waals interaction is the dominant factor for the chemical reactivity of graphene on two-dimensional (2D) heterostructures. A significant enhancement in the chemical stability of graphene is achieved by replacing the common SiO2 substrate with 2D crystals such as an additional graphene layer, WS2, MoS2, or h-BN. Our theoretical and experimental results show that its origin is a strong van der Waals interaction between the graphene layer and the 2D substrate. This results in a high resistive force on graphene toward geometric lattice deformation. We also demonstrate that the chemical reactivity of graphene can be controlled by the relative lattice orientation with respect to the substrates and thus can be used for a wide range of applications including hydrogen storage.

  13. Stochastic bifurcations in a bistable Duffing-Van der Pol oscillator with colored noise.

    PubMed

    Xu, Yong; Gu, Rencai; Zhang, Huiqing; Xu, Wei; Duan, Jinqiao

    2011-05-01

    This paper aims to investigate Gaussian colored-noise-induced stochastic bifurcations and the dynamical influence of correlation time and noise intensity in a bistable Duffing-Van der Pol oscillator. By using the stochastic averaging method, theoretically, one can obtain the stationary probability density function of amplitude for the Duffing-Van der Pol oscillator and can reveal interesting dynamics under the influence of Gaussian colored noise. Stochastic bifurcations are discussed through a qualitative change of the stationary probability distribution, which indicates that system parameters, noise intensity, and noise correlation time, respectively, can be treated as bifurcation parameters. They also imply that the effects of multiplicative noise are rather different from that of additive noise. The results of direct numerical simulation verify the effectiveness of the theoretical analysis. Moreover, the largest Lyapunov exponent calculations indicate that P and D bifurcations have no direct connection. PMID:21728638

  14. van der Waals interactions at the nanoscale: The effects of nonlocality

    PubMed Central

    Luo, Yu; Zhao, Rongkuo; Pendry, John B.

    2014-01-01

    Calculated using classical electromagnetism, the van der Waals force increases without limit as two surfaces approach. In reality, the force saturates because the electrons cannot respond to fields of very short wavelength: polarization charges are always smeared out to some degree and in consequence the response is nonlocal. Nonlocality also plays an important role in the optical spectrum and distribution of the modes but introduces complexity into calculations, hindering an analytical solution for interactions at the nanometer scale. Here, taking as an example the case of two touching nanospheres, we show for the first time, to our knowledge, that nonlocality in 3D plasmonic systems can be accurately analyzed using the transformation optics approach. The effects of nonlocality are found to dramatically weaken the field enhancement between the spheres and hence the van der Waals interaction and to modify the spectral shifts of plasmon modes. PMID:25468982

  15. The gene for the Ellis-van Creveld syndrome is located on chromosome 4p16.

    PubMed

    Polymeropoulos, M H; Ide, S E; Wright, M; Goodship, J; Weissenbach, J; Pyeritz, R E; Da Silva, E O; Ortiz De Luna, R I; Francomano, C A

    1996-07-01

    Ellis-van Creveld syndrome (EVC) is an autosomal recessive disorder characterized by disproportionate dwarfism, polydactyly, and congenital heart disease. This rare disorder is found with increased frequency among the Old Order Amish community in Lancaster County, Pennsylvania. We have used linkage analysis to localize the gene responsible for the EVC phenotype in nine interrelated Amish pedigrees and three unrelated families from Mexico, Ecuador, and Brazil. We now report the linkage for the Ellis-van Creveld syndrome gene to markers on the distal short arm of human chromosome 4, with Zmax = 6.91 at theta = 0.02 for marker HOX7, in a region proximal to the FGFR3 gene responsible for the achondroplasia phenotype. PMID:8661097

  16. First principles calculations of solid-state thermionic transport in layered van der Waals heterostructures

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoming; Zebarjadi, Mona; Esfarjani, Keivan

    2016-08-01

    This work aims at understanding solid-state energy conversion and transport in layered (van der Waals) heterostructures in contact with metallic electrodes via a first-principles approach. As an illustration, a graphene/phosphorene/graphene heterostructure in contact with gold electrodes is studied by using density functional theory (DFT)-based first principles calculations combined with real space Green's function (GF) formalism. We show that for a monolayer phosphorene, quantum tunneling dominates the transport. By adding more phosphorene layers, one can switch from tunneling-dominated transport to thermionic-dominated transport, resulting in transporting more heat per charge carrier, thus, enhancing the cooling coefficient of performance. The use of layered van der Waals heterostructures has two advantages: (a) thermionic transport barriers can be tuned by changing the number of layers, and (b) thermal conductance across these non-covalent structures is very weak. The phonon thermal conductance of the present van der Waals heterostructure is found to be 4.1 MW m-2 K-1 which is one order of magnitude lower than the lowest value for that of covalently-bonded interfaces. The thermionic coefficient of performance for the proposed device is 18.5 at 600 K corresponding to an equivalent ZT of 0.13, which is significant for nanoscale devices. This study shows that layered van der Waals structures have great potential to be used as solid-state energy-conversion devices.This work aims at understanding solid-state energy conversion and transport in layered (van der Waals) heterostructures in contact with metallic electrodes via a first-principles approach. As an illustration, a graphene/phosphorene/graphene heterostructure in contact with gold electrodes is studied by using density functional theory (DFT)-based first principles calculations combined with real space Green's function (GF) formalism. We show that for a monolayer phosphorene, quantum tunneling dominates the

  17. On the pseudopotential approximation in the van der Waals density functional calculations

    NASA Astrophysics Data System (ADS)

    Hamada, Ikutaro; Callsen, Martin

    The van der Waals density functional (vdW-DF) is a density functional that is able to describe van der Waals and covalent interactions in a seamless fashion, and has been applied to a variety of systems. In practical calculations, the pseudopotential (PP) approximation has been employed, for which the PPs should be generated consistently for the chosen exchange correlation XC functional. However, usually PPs generated with a generalized gradient approximation (GGA) XC functional are used and the effect of the approximation to the XC functional applied in the PP generation is scarcely discussed. In this work, we discuss the appropriate XC functionals in the PP generation for the vdW-DF calculations. Furthermore, we compare the vdW-DF results for several systems using the PP's generated with appropriate XC and those with GGA XC.

  18. Nuclear spin-spin coupling anisotropy in the van der Waals-bonded 129Xe dimer.

    PubMed

    Jokisaari, Jukka; Vaara, Juha

    2013-07-21

    The spin-spin coupling constant, J, in the van der Waals-bonded (129)Xe-(129)Xe dimer cannot be determined experimentally because of the magnetic equivalence of the two nuclei. In contrast, the anisotropy of the coupling tensor, ΔJ, can be obtained from the so called effective dipole-dipole coupling determined in a solid state inclusion compound whose cages accommodate two xenon atoms. For the determination of the experimental ΔJ((129)Xe, (129)Xe) we exploited the data reported earlier in this journal. [D. H. Brouwer et al., Phys. Chem. Chem. Phys., 2007, 9, 1093.] The experimental value and the value obtained from relativistic first-principles computation are in perfect agreement. To the best of our knowledge this is the first investigation of spin-spin coupling anisotropy in a van der Waals-bonded system. PMID:23743998

  19. William P. van Wagenen and the first corpus callosotomies for epilepsy.

    PubMed

    Mathews, Marlon S; Linskey, Mark E; Binder, Devin K

    2008-03-01

    As a trainee of Dr. Harvey Cushing, cofounder and first president of the American Association of Neurological Surgeons, and founder of a prestigious international academic fellowship, Dr. William P. van Wagenen is an important figure in the history of neurological surgery. Perhaps less well known or appreciated is his seminal role as the first neurosurgeon to attempt, study, and publish results of the corpus callosotomy procedure for patients with epilepsy, and his collaboration with Andrew J. Akelaitis, which led to the description of some features of "split-brain" patients 2 decades before similar work in the 1960s eventually resulted in a Nobel Prize for Roger W. Sperry in 1981. These contributions firmly establish William P. van Wagenen as one of the founding pioneers in the surgical treatment of patients with epilepsy. PMID:18312112

  20. Automated determination of electron density from electric field measurements on the Van Allen Probes spacecraft

    NASA Astrophysics Data System (ADS)

    Zhelavskaya, Irina; Kurth, William; Spasojevic, Maria; Shprits, Yuri

    2016-07-01

    We present the Neural-network-based Upper-hybrid Resonance Determination (NURD) algorithm for automatic inference of the electron number density from plasma wave measurements made onboard NASA's Van Allen Probes mission. A feedforward neural network is developed to determine the upper hybrid resonance frequency, f_{uhr}, from electric field measurements, which is then used to calculate the electron number density. In previous missions, the plasma resonance bands were manually identified, and there have been few attempts to do robust, routine automated detections. We describe the design and implementation of the algorithm and perform an initial analysis of the resulting electron number density distribution obtained by applying NURD to 2.5 years of data collected with the EMFISIS instrumentation suite of the Van Allen Probes mission. Densities obtained by NURD are compared to those obtained by another recently developed automated technique and also to an existing empirical plasmasphere and trough density model.

  1. [Legitimation of Andries Van Wesele, Andreas Vesalius's father, by the Holy Roman Emperor Charles the Fifth].

    PubMed

    Izumi, Hyonosuke

    2006-06-01

    Andries van Wesele, Andreas Vesalius's father and a court pharmacist of the Holy Roman Emperor Charles the fifth, was an illegitimate son of Everard van Wesele, a court physician of the Hapsburgs. In the year of 1531, Andries was legitimated by the Emperor. The legitimation letter was written in French. The author tried to translate and analyze the letter. By this legitimation, not only Andries himself was legitimated but also his successors were approved to succeed Andries. By this letter, Andreas Vesalius obtained his position as a hereditary member of a family serving the court of the Hapsburgs, and as a result, he started his career as a physician of the court. PMID:17152536

  2. Stochastic bifurcations in a bistable Duffing-Van der Pol oscillator with colored noise.

    PubMed

    Xu, Yong; Gu, Rencai; Zhang, Huiqing; Xu, Wei; Duan, Jinqiao

    2011-05-01

    This paper aims to investigate Gaussian colored-noise-induced stochastic bifurcations and the dynamical influence of correlation time and noise intensity in a bistable Duffing-Van der Pol oscillator. By using the stochastic averaging method, theoretically, one can obtain the stationary probability density function of amplitude for the Duffing-Van der Pol oscillator and can reveal interesting dynamics under the influence of Gaussian colored noise. Stochastic bifurcations are discussed through a qualitative change of the stationary probability distribution, which indicates that system parameters, noise intensity, and noise correlation time, respectively, can be treated as bifurcation parameters. They also imply that the effects of multiplicative noise are rather different from that of additive noise. The results of direct numerical simulation verify the effectiveness of the theoretical analysis. Moreover, the largest Lyapunov exponent calculations indicate that P and D bifurcations have no direct connection.

  3. Two dimensional graphene nanogenerator by coulomb dragging: Moving van der Waals heterostructure

    SciTech Connect

    Zhong, Huikai; Li, Xiaoqiang; Wu, Zhiqian; Zhang, Shengjiao; Xu, Zhijuan; Chen, Hongsheng; Lin, Shisheng

    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 between 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.

  4. Fermi Surface and Van Hove Singularities in the Itinerant Metamagnet Sr(3)Ru(2)O(7)

    SciTech Connect

    Tamai, A.; Allan, M.P.; Mercure, J.F.; Meevasana, W.; Dunkel, R.; Lu, D.H.; Perry, R.S.; Mackenzie, A.P.; Singh, D.J.; Shen, Z.-X.; Baumberger, F.; /Scottish U. Research Reactor Ctr. /St. Andrews U.

    2011-01-04

    The low-energy electronic structure of the itinerant metamagnet Sr{sub 3}Ru{sub 2}O{sub 7} is investigated by angle resolved photoemission and density functional calculations. We find well-defined quasiparticle bands with resolution limited line widths and Fermi velocities up to an order of magnitude lower than in single layer Sr{sub 2}RuO{sub 4}. The complete topography, the cyclotron masses and the orbital character of the Fermi surface are determined, in agreement with bulk sensitive de Haas - van Alphen measurements. An analysis of the dxy band dispersion reveals a complex density of states with van Hove singularities (vHs) near the Fermi level; a situation which is favorable for magnetic instabilities.

  5. Automated Determination of Electron Density from Electric Field Measurements on the Van Allen Probes Spacecraft

    NASA Astrophysics Data System (ADS)

    Zhelavskaya, Irina; Spasojevic, Maria; Shprits, Yuri; Kurth, William

    2016-04-01

    We present the Neural-network-based Upper-hybrid Resonance Determination (NURD) algorithm for automatic inference of the electron number density from plasma wave measurement made onboard NASA's Van Allen Probes mission. A feedforward neural network is developed to determine the upper hybrid resonance frequency, fuhr, from electric field measurements, which is then used to calculate the electron number density. In previous missions, the plasma resonance bands were manually identified, and there have been few attempts to do robust, routine automated detection. We describe the design and implementation of the algorithm and perform initial analysis of the resulting electron number density distribution obtained by applying NURD to 2.5 years of data collected with the EMFISIS instrumentation suite of the Van Allen Probes mission. Densities obtained by NURD are compared to those obtained by another recently developed automated technique and also to an existing empirical plasmasphere and trough density model.

  6. Automated determination of electron density from electric field measurements on the Van Allen Probes spacecraft

    NASA Astrophysics Data System (ADS)

    Zhelavskaya, I. S.; Spasojevic, M.; Shprits, Y. Y.; Kurth, W. S.

    2016-05-01

    We present the Neural-network-based Upper hybrid Resonance Determination (NURD) algorithm for automatic inference of the electron number density from plasma wave measurements made on board NASA's Van Allen Probes mission. A feedforward neural network is developed to determine the upper hybrid resonance frequency, fuhr, from electric field measurements, which is then used to calculate the electron number density. In previous missions, the plasma resonance bands were manually identified, and there have been few attempts to do robust, routine automated detections. We describe the design and implementation of the algorithm and perform an initial analysis of the resulting electron number density distribution obtained by applying NURD to 2.5 years of data collected with the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrumentation suite of the Van Allen Probes mission. Densities obtained by NURD are compared to those obtained by another recently developed automated technique and also to an existing empirical plasmasphere and trough density model.

  7. Detection of vanA-containing Enterococcus species in faecal microbiota of gilthead seabream (Sparus aurata).

    PubMed

    Barros, Joana; Andrade, Margarida; Radhouani, Hajer; López, Maria; Igrejas, Gilberto; Poeta, Patricia; Torres, Carmen

    2012-01-01

    Vancomycin-resistant Enterococcus faecalis, E. faecium and E. durans isolates with the genotype vanA were detected in 7 of 118 faecal samples (5.9%) of natural gilthead seabream recovered off the coast of Portugal, and one vancomycin-resistant isolate/sample was further characterized. The genes erm(B), tet(L), tet(M), aac(6')-aph(2"), aph(3')-IIIa and/or ant(6)-Ia were identified in most of the 7 vancomycin-resistant enterococci. Sequence types ST273, ST313 and ST76 were detected in three E. faecium isolates and ST6 in two E. faecalis isolates. VanA-containing enterococci are suggested to be disseminated in fish in marine ecosystems close to areas of human activity.

  8. Bonding in mercury-alkali molecules: Orbital-driven van der Waals complexes.

    PubMed

    Kraka, Elfi; Cremer, Dieter

    2008-06-01

    The bonding situation in mercury-alkali diatomics HgA ((2)Sigma(+)) (A = Li, Na, K, Rb) has been investigated employing the relativistic all-electron method Normalized Elimination of the Small Component (NESC), CCSD(T), and augmented VTZ basis sets. Although Hg,A interactions are typical of van der Waals complexes, trends in calculated D(e) values can be explained on the basis of a 3-electron 2-orbital model utilizing calculated ionization potentials and the D(e) values of HgA(+)((1)Sigma(+)) diatomics. HgA molecules are identified as orbital-driven van der Waals complexes. The relevance of results for the understanding of the properties of liquid alkali metal amalgams is discussed.

  9. Nuclear spin-spin coupling anisotropy in the van der Waals-bonded 129Xe dimer.

    PubMed

    Jokisaari, Jukka; Vaara, Juha

    2013-07-21

    The spin-spin coupling constant, J, in the van der Waals-bonded (129)Xe-(129)Xe dimer cannot be determined experimentally because of the magnetic equivalence of the two nuclei. In contrast, the anisotropy of the coupling tensor, ΔJ, can be obtained from the so called effective dipole-dipole coupling determined in a solid state inclusion compound whose cages accommodate two xenon atoms. For the determination of the experimental ΔJ((129)Xe, (129)Xe) we exploited the data reported earlier in this journal. [D. H. Brouwer et al., Phys. Chem. Chem. Phys., 2007, 9, 1093.] The experimental value and the value obtained from relativistic first-principles computation are in perfect agreement. To the best of our knowledge this is the first investigation of spin-spin coupling anisotropy in a van der Waals-bonded system.

  10. Van Allen Probe Spacecraft Potential Fluctuations and Electromagnetic Waves: A Parameter Space Survey

    NASA Astrophysics Data System (ADS)

    Sturner, A. P.; Ergun, R.; Malaspina, D.

    2013-12-01

    The study of chorus waves, an important mechanism for the energization and loss of particles in the radiation belts and inner magnetosphere, has been significantly aided by observations of fluctuations in a spacecraft's potential, which have been shown to be correlated with plasma density structures. However, recent analysis of Van Allen Probe data suggests that the oscillatory electromagnetic fields of chorus waves may also induce spacecraft potential fluctuations via enhanced photoelectron escape, calling into question our understanding of chorus waves. We use a fully 3D particle tracing simulation to study the equilibrium potential of a model Van Allen Probe spacecraft under various plasma conditions, varying thermal temperature, electric and magnetic field strength, plasma density, etc., to better understand the parameter space under which enhanced photoelectron escape becomes important.

  11. van der Waals forces in density functional theory: Perturbational long-range electron-interaction corrections

    SciTech Connect

    Angyan, Janos G.; Gerber, Iann C.; Savin, Andreas; Toulouse, Julien

    2005-07-15

    Long-range exchange and correlation effects, responsible for the failure of currently used approximate density functionals in describing van der Waals forces, are taken into account explicitly after a separation of the electron-electron interaction in the Hamiltonian into short- and long-range components. We propose a 'range-separated hybrid' functional based on a local density approximation for the short-range exchange-correlation energy, combined with a long-range exact exchange energy. Long-range correlation effects are added by a second-order perturbational treatment. The resulting scheme is general and is particularly well adapted to describe van der Waals complexes, such as rare gas dimers.

  12. A new addition to the genus Anthalona Van Damme, Sinev & Dumont, 2011 (Branchiopoda: Anomopoda: Chydoridae).

    PubMed

    Damme, Kay Van

    2016-01-01

    Continued fine-tuning of taxonomy in the Chydoridae Dybowksi & Grochowski, 1894 (Crustacea: Branchiopoda: Anomopoda) is important for the assessment of the diversity in this speciose family and our progress in chydorid biogeography and evolution. The continuation of the taxonomical study of single taxa, however tedious and seemingly unimportant, provides a fundamental basis for applied fields. Within this context, morphological studies on lesser known taxa and the establishment of their validity should continue, as so many uncertainties remain, e.g., in the lump genus Alona Baird, 1843 (Van Damme et al. 2010). Recent studies suggest that we are still far from a realistic image on cladoceran diversity, in particular for the Chydoridae (Forró et al. 2008, Van Damme et al. 2010). The current correspondence discusses the validity and the position of a single species, Alona milleri Kiser, 1948, originally described from the Pearl River, China (Kiser 1948). PMID:27470817

  13. Prosthodontic Rehabilitation for a Patient with Ellis-Van Creveld Syndrome: A Case Report.

    PubMed

    Siddiqui, Muhammad Musaab; Taylor, Philip D

    2016-03-01

    Patients suffering from Ellis-Van-Creveld syndrome are a challenge for dental management. Aesthetics are a major concern with limited manual dexterity, making choice of treatment critical. A 38 year old female diagnosed with Ellis-Van-Creveld syndrome presented with stained teeth and un-aesthetic smile and related that to her low self-esteem and depression. Intra-oral examination revealed mal-aligned megadont central incisors in the maxillary arch, fused mandibular canines with laterals and missing central incisors with space discrepancy and pronounced reverse over jet and overbite. Treatment involved non-surgical periodontal management, fabrication of veneers and dentine bonded crowns for maxillary anteriors and fixed-fixed resin retained bridge for mandibular arch. PMID:27039477

  14. Electron acceleration in the heart of the Van Allen radiation belts.

    PubMed

    Reeves, G D; Spence, H E; Henderson, M G; Morley, S K; Friedel, R H W; Funsten, H O; Baker, D N; Kanekal, S G; Blake, J B; Fennell, J F; Claudepierre, S G; Thorne, R M; Turner, D L; Kletzing, C A; Kurth, W S; Larsen, B A; Niehof, J T

    2013-08-30

    The Van Allen radiation belts contain ultrarelativistic electrons trapped in Earth's magnetic field. Since their discovery in 1958, a fundamental unanswered question has been how electrons can be accelerated to such high energies. Two classes of processes have been proposed: transport and acceleration of electrons from a source population located outside the radiation belts (radial acceleration) or acceleration of lower-energy electrons to relativistic energies in situ in the heart of the radiation belts (local acceleration). We report measurements from NASA's Van Allen Radiation Belt Storm Probes that clearly distinguish between the two types of acceleration. The observed radial profiles of phase space density are characteristic of local acceleration in the heart of the radiation belts and are inconsistent with a predominantly radial acceleration process.

  15. van der Waals binding and band structure effects in graphene overlayers and graphane multilayers

    NASA Astrophysics Data System (ADS)

    Hyldgaard, Per; Rohrer, Jochen

    2011-03-01

    We study graphene formation (by selective Si evaporation) and adhesion on SiC surfaces as well as stacking and binding of graphane multilayers using a number of versions of the van der Waals Density Functional (vdW-DF) method and plane-wave density functional theory calculations. For the graphene/SiC systems and for the graphane multilayers we document that the bonding is entirely dominated by van der Waals (vdW) forces. At the same time we find that dispersive forces acting on the layers produce significant modifications in the graphene and graphane band structure. We interpret the changes and discuss a competition between wave function hybridization and interaction with the charge enhancement (between the layers) that results from density overlap. Supported by Svenska Vetenskapsrådet VR #621-2008-4346.

  16. Spectroscopic measurement of the titanium-helium van der Waals molecule: TiHe

    NASA Astrophysics Data System (ADS)

    Quiros, Nancy; Tariq, Naima; Weinstein, Jonathan

    2016-05-01

    Atoms that are weakly bound by the van der Waals (vdW) interaction are known as van der Waals molecules. The existence and formation of vdW molecules is favorable at low temperatures due to their weak binding energy. We have used laser ablation and helium buffer gas cooling to create the exotic vdW diatomic molecule made of titanium (Ti) and helium (He). TiHe molecules were detected through laser-induced-fluorescence spectroscopy closely blue-detuned from the a3F2 --> y3F3 atomic Ti transition at 25227 cm-1. Measurements of the binding energy of TiHe were obtained by studying its equilibrium thermodynamic properties. It is believed the molecules are formed from the constituent cold atoms through three-body recombination. Progress towards measuring the three-body recombination rate coefficient will be discussed. This material is based upon work supported by National Science Foundation under Grant No. PHY 1265905.

  17. Stochastic bifurcations induced by correlated noise in a birhythmic van der Pol system

    NASA Astrophysics Data System (ADS)

    Mbakob Yonkeu, R.; Yamapi, R.; Filatrella, G.; Tchawoua, C.

    2016-04-01

    We investigate the effects of exponentially correlated noise on birhythmic van der Pol type oscillators. The analytical results are obtained applying the quasi-harmonic assumption to the Langevin equation to derive an approximated Fokker-Planck equation. This approach allows to analytically derive the probability distributions as well as the activation energies associated to switching between coexisting attractors. The stationary probability density function of the van der Pol oscillator reveals the influence of the correlation time on the dynamics. Stochastic bifurcations are discussed through a qualitative change of the stationary probability distribution, which indicates that noise intensity and correlation time can be treated as bifurcation parameters. Comparing the analytical and numerical results, we find good agreement both when the frequencies of the attractors are about equal or when they are markedly different.

  18. William P. van Wagenen and the first corpus callosotomies for epilepsy.

    PubMed

    Mathews, Marlon S; Linskey, Mark E; Binder, Devin K

    2008-03-01

    As a trainee of Dr. Harvey Cushing, cofounder and first president of the American Association of Neurological Surgeons, and founder of a prestigious international academic fellowship, Dr. William P. van Wagenen is an important figure in the history of neurological surgery. Perhaps less well known or appreciated is his seminal role as the first neurosurgeon to attempt, study, and publish results of the corpus callosotomy procedure for patients with epilepsy, and his collaboration with Andrew J. Akelaitis, which led to the description of some features of "split-brain" patients 2 decades before similar work in the 1960s eventually resulted in a Nobel Prize for Roger W. Sperry in 1981. These contributions firmly establish William P. van Wagenen as one of the founding pioneers in the surgical treatment of patients with epilepsy.

  19. 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

  20. [The development of Rein van Bemmelens (1904-1983) undation theory: forty years of Dutch geology].

    PubMed

    Barzilay, Willemjan

    2009-01-01

    The Dutch geologist Rein van Bemmelen was the greatest opponent of plate tectonics in The Netherlands. He lived and worked during an important period in the history of earth sciences. He had studied geology when Wegeners theory was introduced and enthusiastically received in the Netherlands and he worked as a geologists during the period in which, after Wegeners theory was rejected in The Netherlands, several Dutch geologists came with their own theories to explain the origin of continents and oceans and in which plate tectonics was introduced in The Netherlands. He had proposed his own theory, the undation theory, at the beginning of the 1930s and kept on developing it during the following years. He continued to do so until his death in 1983. The history of the undation theory thus sheds light on the history of geology in The Netherlands. I will trace the history of geology in The Netherlands using Rein van Bemmelen and his undation theory as a lens.

  1. Microwave spectra of van der Waals complexes of importance in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Suenram, R. D.; Lovas, F. J.

    1990-01-01

    The Fourier-transform Fabry-Perot pulsed-molecular-beam microwave spectrometer at NIST was used to study the microwave spectra of a number of molecular dimers and trimers that may be present in planetary atmospheres. The weak van der Waals bonds associated with these species usually give rise to rotational-tunneling splittings in the microwave spectra. The microwave spectrum of the water dimer species was used to illustrate the complications that can arise in the study of the rotational spectra of these loosely bound species. In addition to the water dimer species, the microwave spectra of the following hydrogen-bonded and van der Waals complexes were studied: (CO2)2-H2O, CO2-(H2O)2, CO2-H2S, N2-H2O, CO-H2O, SO2-H2O, and O3-H2O.

  2. The Van der Woude syndrome: a case report and review of the literature.

    PubMed

    Dissemond, J; Haberer, D; Franckson, T; Hillen, U

    2004-09-01

    The Van der Woude syndrome is a rare autosomal dominant developmental malformation usually associated with bilateral lower lip pits. These congenital lip pits appear clinically as a malformation in the vermilion border of the lip, with or without excretion. As a genetic defect has been identified as a microdeletion of chromosome bands 1q32-q41, genetic counselling of patients may be considered. A nonsense mutation in the interferon regulatory factor-6 (IRF-6) is discussed as a pathogenic relevant factor. Therapeutic intervention is generally not necessary, although surgical excision is especially indicated in patients with recurrent inflammation. Physicians should be aware of the Van der Woude syndrome because it has been reported to be associated with a variety of malformations or other congenital disorders. PMID:15324408

  3. Van der Waals pressure and its effect on trapped interlayer molecules

    NASA Astrophysics Data System (ADS)

    Vasu, K. S.; Prestat, E.; Abraham, J.; Dix, J.; Kashtiban, R. J.; Beheshtian, J.; Sloan, J.; Carbone, P.; Neek-Amal, M.; Haigh, S. J.; Geim, A. K.; Nair, R. R.

    2016-07-01

    Van der Waals assembly of two-dimensional crystals continue attract intense interest due to the prospect of designing novel materials with on-demand properties. One of the unique features of this technology is the possibility of trapping molecules between two-dimensional crystals. The trapped molecules are predicted to experience pressures as high as 1 GPa. Here we report measurements of this interfacial pressure by capturing pressure-sensitive molecules and studying their structural and conformational changes. Pressures of 1.2+/-0.3 GPa are found using Raman spectrometry for molecular layers of 1-nm in thickness. We further show that this pressure can induce chemical reactions, and several trapped salts are found to react with water at room temperature, leading to two-dimensional crystals of the corresponding oxides. This pressure and its effect should be taken into account in studies of van der Waals heterostructures and can also be exploited to modify materials confined at the atomic interfaces.

  4. A simplified implementation of van der Waals density functionals for first-principles molecular dynamics applications

    NASA Astrophysics Data System (ADS)

    Wu, Jun; Gygi, François

    2012-06-01

    We present a simplified implementation of the non-local van der Waals correlation functional introduced by Dion et al. [Phys. Rev. Lett. 92, 246401 (2004)] and reformulated by Román-Pérez et al. [Phys. Rev. Lett. 103, 096102 (2009)]. The proposed numerical approach removes the logarithmic singularity of the kernel function. Complete expressions of the self-consistent correlation potential and of the stress tensor are given. Combined with various choices of exchange functionals, five versions of van der Waals density functionals are implemented. Applications to the computation of the interaction energy of the benzene-water complex and to the computation of the equilibrium cell parameters of the benzene crystal are presented. As an example of crystal structure calculation involving a mixture of hydrogen bonding and dispersion interactions, we compute the equilibrium structure of two polymorphs of aspirin (2-acetoxybenzoic acid, C9H8O4) in the P21/c monoclinic structure.

  5. vanG Element Insertions within a Conserved Chromosomal Site Conferring Vancomycin Resistance to Streptococcus agalactiae and Streptococcus anginosus

    PubMed Central

    Srinivasan, Velusamy; Metcalf, Benjamin J.; Knipe, Kristen M.; Ouattara, Mahamoudou; McGee, Lesley; Shewmaker, Patricia L.; Glennen, Anita; Nichols, Megin; Harris, Carol; Brimmage, Mary; Ostrowsky, Belinda; Park, Connie J.; Schrag, Stephanie J.; Frace, Michael A.; Sammons, Scott A.

    2014-01-01

    ABSTRACT Three vancomycin-resistant streptococcal strains carrying vanG elements (two invasive Streptococcus agalactiae isolates [GBS-NY and GBS-NM, both serotype II and multilocus sequence type 22] and one Streptococcus anginosus [Sa]) were examined. The 45,585-bp elements found within Sa and GBS-NY were nearly identical (together designated vanG-1) and shared near-identity over an ~15-kb overlap with a previously described vanG element from Enterococcus faecalis. Unexpectedly, vanG-1 shared much less homology with the 49,321-bp vanG-2 element from GBS-NM, with widely different levels (50% to 99%) of sequence identity shared among 44 related open reading frames. Immediately adjacent to both vanG-1 and vanG-2 were 44,670-bp and 44,680-bp integrative conjugative element (ICE)-like sequences, designated ICE-r, that were nearly identical in the two group B streptococcal (GBS) strains. The dual vanG and ICE-r elements from both GBS strains were inserted at the same position, between bases 1328 and 1329, within the identical RNA methyltransferase (rumA) genes. A GenBank search revealed that although most GBS strains contained insertions within this specific site, only sequence type 22 (ST22) GBS strains contained highly related ICE-r derivatives. The vanG-1 element in Sa was also inserted within this position corresponding to its rumA homolog adjacent to an ICE-r derivative. vanG-1 insertions were previously reported within the same relative position in the E. faecalis rumA homolog. An ICE-r sequence perfectly conserved with respect to its counterpart in GBS-NY was apparent within the same site of the rumA homolog of a Streptococcus dysgalactiae subsp. equisimilis strain. Additionally, homologous vanG-like elements within the conserved rumA target site were evident in Roseburia intestinalis. PMID:25053786

  6. The role of collective motion in the ultrafast charge transfer in van der Waals heterostructures

    DOE PAGESBeta

    Wang, Han; Bang, Junhyeok; Sun, Yiyang; West, Damien; Meunier, Vincent; Zhang, Shengbai; Liang, Linagbo

    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

  7. Estimation of Some Parameters from Morse-Morse-Spline-Van Der Waals Intermolecular Potential

    SciTech Connect

    Coroiu, I.

    2007-04-23

    Some parameters such as transport cross-sections and isotopic thermal diffusion factor have been calculated from an improved intermolecular potential, Morse-Morse-Spline-van der Waals (MMSV) potential proposed by R.A. Aziz et al. The treatment was completely classical and no corrections for quantum effects were made. The results would be employed for isotope separations of different spherical and quasi-spherical molecules.

  8. [Physiological properties of the vancomycin-resistant strain Staphylococcus epidermidis 33 GISK VAN(R)].

    PubMed

    Kononova, L I; Korobov, V P

    2015-01-01

    Physiological properties of a selected Staphylococcus epidermidis strain 33 GISK VAN(R) with high resistance to vancomycin, multiple resistance to various antibiotics, as well as decreased sensitivity to lysozyme, lysostaphin, and the low-molecular mass peptide warnerin were studied. The strain was characterized by a thicker cell wall, resulting in considerably decreased rates of vancomycin penetration into the cells and in limited access of the antibiotic to its targets on the bacterial membrane.

  9. 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.

  10. Van der woude syndrome associated with hypodontia: a rare clinical entity.

    PubMed

    Soni, Romesh; Vivek, Rajul; Srivastava, Adit; Singh, Ankita; Srivastava, Shalabh; Chaturvedi, T P

    2012-01-01

    Van der Woude syndrome (VWS) is usually underreported and frequently not diagnosed. The phenomenon that cleft lip and palate are regularly combined in the same pedigree makes it unique. A meticulous examination of a patient with lip pits may reveal a hidden form of a cleft, for example, submucous. This paper presents a case of VWS in a ten-year-old boy with characteristic orofacial features. Special emphasis has also been given on the need for appropriate genetic counseling. PMID:23326687

  11. Stability analysis for periodic solutions of the Van der Pol-Duffing forced oscillator

    NASA Astrophysics Data System (ADS)

    Cui, Jifeng; Liang, Jiaming; Lin, Zhiliang

    2016-01-01

    Based on the homotopy analysis method (HAM), the high accuracy frequency response curve and the stable/unstable periodic solutions of the Van der Pol-Duffing forced oscillator with the variation of the forced frequency are obtained and studied. The stability of the periodic solutions obtained is analyzed by use of Floquet theory. Furthermore, the results are validated in the light of spectral analysis and bifurcation theory.

  12. EXPERIMENTAL AND THEORETICAL STUDIES OF THE CN-AR VAN DER WAALS COMPLEX

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The CN-Ar van der Waals complex has been observed using B2E+-X2E+ and A2II-X2E+ electronic transitions. The spectra yielded a dissociation energy of D0"=109+2 cm1 and a zero point rational constant of B0"=0.067+0.005 cm-1 for CN(x)-Ar. The dissociation energy for Cn(A)-Ar was found to be D0"=132+2...

  13. [From gene to disease; EVC, EVC2, and Ellis-van Creveld syndrome].

    PubMed

    van Hagen, J M; Baart, J A; Gille, J J P

    2005-04-23

    Ellis-van Creveld syndrome is an autosomal recessive disorder characterised by short stature with short limbs, postaxial polydactyly and congenital cardiac defects. The syndrome can be caused by mutations in the EVC gene or the EVC2 gene. The genes are located close to each other in a head-to-head configuration on chromosome 4p16. Clinical diagnosis can be confirmed by DNA analysis, which is currently offered by two laboratories in Italy.

  14. American crows as carriers of vancomycin-resistant enterococci with vanA gene.

    PubMed

    Oravcova, Veronika; Zurek, Ludek; Townsend, Andrea; Clark, Anne B; Ellis, Julie C; Cizek, Alois; Literak, Ivan

    2014-04-01

    We studied the vanA-carrying vancomycin-resistant enterococci (VRE) isolated from American crows in the United States during the winter 2011/2012. Faecal samples from crows were cultured selectively for VRE and characterized. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to examine epidemiological relationships of vanA-containing VRE. Isolates were tested in vitro for their ability to horizontally transfer the vancomycin resistance trait. VRE with the vanA gene were found in 15 (2.5%) of 590 crows samples, from which we obtained 22 different isolates. Enterococcal species were Enterococcus faecium (14) and E. faecalis (8). One, two and 19 isolates originated from Kansas, New York State and Massachusetts, respectively. Based on MLST analysis, E. faecium isolates were grouped as ST18 (6 isolates), ST555 (2), and novel types ST749 (1), ST750 (3), ST751 (1), ST752 (1). Enterococcus faecalis isolates belonged to ST6 (1), ST16 (3) and ST179 (4). All isolates were able to transfer the vancomycin resistance trait via filter mating with very high transfer range. Clinically important enterococci with the vanA gene occur in faeces of wild American crows throughout the United States. These migrating birds may contribute to the dissemination of VRE in environment over large distances. [Correction added after first online publication on 06 August 2013: The number of E. faecium ST752 isolate is now amended to '1', consistent with that shown in the 'Results' section and Figure 2.].

  15. 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.

  16. Fitness cost of VanA-type vancomycin resistance in methicillin-resistant Staphylococcus aureus.

    PubMed

    Foucault, Marie-Laure; Courvalin, Patrice; Grillot-Courvalin, Catherine

    2009-06-01

    We have quantified the biological cost of VanA-type glycopeptide resistance due to the acquisition of the resistance operon by methicillin-resistant Staphylococcus aureus (MRSA) from Enterococcus sp. Exponential growths of recipient strain HIP11713, its transconjugant VRSA-1, VRSA-5, and VRSA-6 were compared in the absence or, except for HIP11713, in the presence of vancomycin. Induction of resistance was performed by adding vancomycin in both the preculture and the culture or the culture at only 1/50 the MIC. In the absence of vancomycin, the growth rates of the vancomycin-resistant S. aureus (VRSA) strains were similar to that of susceptible MRSA strain HIP11713. When resistance was induced, and under both conditions, there was a significant reduction of the growth rate of the VRSA strains relative to that of HIP11713 and to those of their noninduced counterparts, corresponding to a ca. 20% to 38% reduction in fitness. Competition experiments between isogenic VRSA-1 and HIP11713 mixed at a 1:1, 1:100, or 100:1 ratio revealed a competitive disadvantage of 0.4% to 3% per 10 generations of the transconjugant versus the recipient. This slight fitness burden can be attributed to the basal level of expression of the van genes in the absence of induction combined with a gene dosage effect due to the presence of the van operon on multicopy plasmids. These data indicate that VanA-type resistance, when induced, is highly costly for the MRSA host, whereas in the absence of induction, its biological cost is minimal. Thus, the potential for the dissemination of VRSA clinical isolates should not be underestimated.

  17. Van der Waals epitaxial double heterostructure: InAs/single-layer graphene/InAs.

    PubMed

    Hong, Young Joon; Yang, Jae Won; Lee, Wi Hyoung; Ruoff, Rodney S; Kim, Kwang S; Fukui, Takashi

    2013-12-17

    Van der Waals (vdW) epitaxial double heterostructures have been fabricated by vdW epitaxy of InAs nanostructures on both sides of graphene. InAs nanostructures diametrically form on/underneath graphene exclusively along As-polar direction, indicating polarity inversion of the double heterostructures. First-principles and density functional calculations demonstrate how and why InAs easily form to be double heterostructures with polarity inversion.

  18. Controlled Synthesis of Organic/Inorganic van der Waals Solid for Tunable Light-Matter Interactions.

    PubMed

    Niu, Lin; Liu, Xinfeng; Cong, Chunxiao; Wu, Chunyang; Wu, Di; Chang, Tay Rong; Wang, Hong; Zeng, Qingsheng; Zhou, Jiadong; Wang, Xingli; Fu, Wei; Yu, Peng; Fu, Qundong; Najmaei, Sina; Zhang, Zhuhua; Yakobson, Boris I; Tay, Beng Kang; Zhou, Wu; Jeng, Horng Tay; Lin, Hsin; Sum, Tze Chien; Jin, Chuanhong; He, Haiyong; Yu, Ting; Liu, Zheng

    2015-12-16

    High-quality organic and inorganic van der Waals (vdW) solids are realized using methylammonium lead halide (CH3 NH3 PbI3 ) as the organic part (organic perovskite) and 2D inorganic monolayers as counterparts. By stacking on various 2D monolayers, the vdW solids exhibit dramatically different light emissions. Futhermore, organic/h-BN vdW solid arrays are patterned for red-light emission.

  19. Enterococcus gallinarum carrying the vanA gene cluster: first report in Brazil.

    PubMed

    Camargo, I L B C; Barth, A L; Pilger, K; Seligman, B G S; Machado, A R L; Darini, A L C

    2004-11-01

    In 2000, Enterococcus faecalis resistant to vancomycin was first reported at a tertiary hospital in Porto Alegre, southern Brazil. The resistance spread to other hospitals and surveillance programs were established by hospital infection committees to prevent the spread of vancomycin-resistant enterococci. In February 2002, an isolate initially identified at the genus level as Enterococcus was obtained by surveillance culture (rectal swab) from a patient admitted to a hospital for treatment of septic arthritis in the shoulder. The isolate proved to be resistant to vancomycin by the disc diffusion method and confirmed by an E-test resulting in a minimal inhibitory concentration of > or = 256 microg/ml. This isolate was sent to a reference laboratory (Laboratorio Especial de Bacteriologia e Epidemiologia Molecular, Faculdade de Ciencias Farmaceuticas de Ribeirao Preto, USP) for further study and proved to be an E. gallinarum by the polymerase chain reaction (PCR) using specific primers for the species. Due to the phenotype of unusually high vancomycin resistance, the isolate presumably had the resistance genes (vanA and vanB) and this was confirmed by PCR, which indicated the presence of the vanA gene. A 10.8-kb Tn1546-related transposon was also identified by long-PCR. Interspecies transfer of the vancomycin-resistance gene from the donor E. gallinarum was performed in a successful conjugation experiment in vitro, using E. faecium GE-1 and E. faecalis JH22 as receptors. This is the first report of the detection of a vanA determinant naturally acquired by E. gallinarum in Brazil, indicating the importance of characterizing VRE by both phenotype and genotype methods.

  20. CONNECTING LOCAL STRUCTURE TO INTERFACE FORMATION: A Molecular Scale van der Waals Theory of Nonuniform Liquids

    NASA Astrophysics Data System (ADS)

    Weeks, John D.

    2002-10-01

    This article reviews a new and general theory of nonuniform fluids that naturally incorporates molecular scale information into the classical van der Waals theory of slowly varying interfaces. The method optimally combines two standard approximations, molecular (mean) field theory to describe interface formation and linear response (or Gaussian fluctuation) theory to describe local structure. Accurate results have been found in many different applications in nonuniform simple fluids and these ideas may have important implications for the theory of hydrophobic interactions in water.