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Sample records for mit der oberflaeche

  1. Umsetzung der Unternehmensstrategie mit der Balanced Scorecard

    NASA Astrophysics Data System (ADS)

    Crespo, Isabel; Bergmann, Lars; Portmann, Stefan; Lacker, Thomas; Lacker, Michael; Fleischmann, Jürgen; Kozó, Hans

    Die Balanced Scorecard (BSC) ist ein Ansatz zum strategischen Management, der neben der Ausrichtung des Unternehmens auf finanzielle Zielwerte ebenso großes Gewicht auf so genannte weiche Faktoren legt, die den wirtschaftlichen Erfolg eines Unternehmens erst ermöglichen. Das entscheidende Merkmal der Balanced Scorecard ist dabei, dass sie ein ausgewogenes System strategischer Ziele herstellt, welches das Unternehmen hinsichtlich der vier Perspektiven Finanzen, Kunden, interne Prozesse und Mitarbeiter und Potenziale strategisch ausrichtet (Kaplan u. Norton 1997).

  2. Erlebniseinkauf in der Innenstadt mit hoher Akzeptanz

    NASA Astrophysics Data System (ADS)

    Pangels, Rolf

    2002-03-01

    Im Oktober 2000 führte die BAG zum zehnten Mal die über die Grenzen des Einzelhandels bekannte Untersuchung "Kundenverkehr" in mehr als hundertfünfzig deutschen Städten durch. In Kooperation mit der Swiss Retail Federation sowie mit Unterstützung der femged (European Federation of Medium-size and Major Retailers) wurde die Untersuchung erstmals auch in der Schweiz und in Österreich durchgeführt. Es beteiligten sich insgesamt 463 Unternehmen an der Untersuchung, die knapp 9,5 Mio. Besucher gezählt haben und davon mehr als 360.000 Kunden nach bestimmten Parametern befragten. Die Daten für Deutschland wurden, wie in den Jahren zuvor, vom Institut für Handelsforschung an der Universität Köln ausgewertet. Die Zahlen der Untersuchung in der Schweiz und Österreich wurden von der wirtschafts- und sozialwissenschaftlichen Beratungsgesellschaft ECON-Consult in Köln zusammengetragen und analysiert.

  3. Physik gestern und heute: Visualisierung mit der Schlierenmethode

    NASA Astrophysics Data System (ADS)

    Heering, Peter

    2006-07-01

    Der Name des österreichischen Forschers Ernst Mach ist heute noch mit der Schallgeschwindigkeit verbunden. Diese Auszeichnung resultiert aus Machs Untersuchungen, wie sich Projektile mit Überschallgeschwindigkeit durch die Luft bewegen. Gerade in jüngster Zeit hat die Anwendung derartiger Methoden durch technische Modifikationen wieder einen Aufschwung erfahren.

  4. Mit Mathematik zu Mehr Intelligenz in der Logistik

    NASA Astrophysics Data System (ADS)

    Möhring, Rolf H.; Schenk, Michael

    Die Lösung logistischer Probleme ist ein wichtiger Aspekt menschlichen Handelns seit Menschen gemeinsam zielgerichtet tätig wurden. Die Grundlagen dessen, was wir heute Logistik nennen, entstammen dem militärischen Bereich. So basierte z. B. das römische Imperium in starkem Maße auf militärisch-logistischen Glanzleistungen. Ob damals bereits mathematische Überlegungen eine Rolle spielten, wissen wir heute nicht. Jedoch versuchte z. B. Napoleon, der mit den bedeutendsten Mathematikern seiner Zeit befreundet war, den Transport seiner Truppen und die Verbreitung von Informationen zu optimieren und strategisch einzusetzen.1,2

  5. Grundsätze über die Anlagen neuer Sternwarten mit Beziehung auf die Sternwarte der Universität Göttingen. Von Georg Heinrich Borheck

    NASA Astrophysics Data System (ADS)

    Beuermann, Klaus; Borheck, Georg Heinrich

    Die Göttinger Sternwarte, Wirkungsstätte des berühmten Gelehrten Carl Friedrich Gauß, ist ein bedeutendes Baudenkmal. Im Jahre 2005 wird sie gemeinsam von der Georg-August-Universität und der Akademie der Wissenschaften zu Göttingen renoviert, um dann als repräsentatives Gebäude der Universität und Arbeitsstätte der Akademie zu dienen. Die Nutzung der historischen Räume für Ausstellungen macht diesen imposanten Bau erstmals der Öffentlichkeit zugänglich. Die Sternwarte war bei ihrer Errichtung vor 200 Jahren ein nach seinerzeit neuesten wissenschaftlichen Erkenntnissen konzipierter Bau, der die Universität Göttingen in eine der vordersten Stellen Europa rückte. Auch aufgrund ihrer Architektur ist sie ein großer Wurf des Göttinger Universitätsbaumeisters Georg Heinrich Borheck. Durch die Kriegswirren der Napoleonischen Zeit zerschlug sich Borhecks Versuch einer Publikation seiner Beschreibung des Baus der Göttinger Sternwarte 1805. Doch seine Schrift ist auch heute noch aktuell und wird mit diesem Band erstmals einer breiten Öffentlichkeit zugängig gemacht. Er zeigt die Grundsätze, nach denen damals öffentliche Bauten konzipiert wurden, erläutert die Bedeutung des Baus aus kunst- und wissenschaftshistorischer Sicht und informiert über die Pläne zur Restaurierung der Sternwarte in einem separaten Beitrag und im Geleitwort des Präsidenten der Georg-August Universität Prof. Dr. Dr. h. c. Kurt von Figura.

  6. Photovoltaik Hybrid-Solarzellen mit Nanopartikeln

    NASA Astrophysics Data System (ADS)

    Leute, Angelika

    2004-09-01

    Die organische Photovoltaik auf der Basis halbleitender Polymere bietet eine kostengünstige Alternative zu Solarzellen aus Silizium. Allerdings weisen die organischen Materialien relativ schlechte Ladungstransporteigenschaften auf. Hybrid-Solarzellen, in denen Polymere mit geeigneten anorganischen Halbleitern kombiniert sind, besitzen einerseits die praktischen Vorteile der Organik und andererseits die hohe Elektronenbeweglichkeit der anorganischen Materialien. Wissenschaftler der Technischen Universität Eindhoven haben kürzlich Hybrid-Solarzellen vorgestellt, die aus einem halbleitenden Polymer mit Zinkoxid-Nanopartikeln bestehen.

  7. Kommunikation mit Mitarbeitern

    NASA Astrophysics Data System (ADS)

    Spychala, Anne; Fleischmann, Jürgen

    Kommunikation ist der Austausch von Nachrichten und Informationen zwischen Mitarbeitern eines Unternehmens (O'Hair et al. 1997). Dieser Austausch kann persönlich, aber z.B. auch per Telefon, E-Mail oder durch Computersysteme erfolgen. In diesem Kapitel betrachten wir die persönliche Kommunikation zwischen Vorgesetzten und Mitarbeitern. Zur persönlichen Kommunikation mit Mitarbeitern zählen sowohl formelle Gespräche mit Mitarbeitern als auch eher informelle Gespräche zwischen Tür und Angel. Die Gespräche können dabei mit einzelnen Mitarbeitern (z.B. jährliches Mitarbeitergespräch) oder mit Gruppen von Mitarbeitern (z.B. regelmäßige Projekt- oder Teambesprechungen) stattfinden.

  8. Unfälle mit Pkw

    NASA Astrophysics Data System (ADS)

    Burg, Heinz

    Der Verkehrsunfall ereignete sich innerorts auf einer Kreuzung mit rechts vor links Regelung. Es galt dort die allgemeine Geschwindigkeitsbegrenzung auf 50 km/h. Zur Unfallzeit war es hell und trocken. Die Fahrbahn hatte eine Schwarzdecke.

  9. Zum Stellenwert der Unterdruck-Instillationstherapie in der Dermatologie.

    PubMed

    Müller, Cornelia Sigrid Lissi; Burgard, Barbara; Zimmerman, Monika; Vogt, Thomas; Pföhler, Claudia

    2016-08-01

    Die Methoden zur Behandlung akuter und chronischer Wunden unterliegen einer steten Weiterentwicklung, Reevaluierung und Anwendung innovativer Therapieformen. Die Vakuumtherapie zur Wundbehandlung gehört zu den etablierten Behandlungsmodalitäten. Ein innovatives Verfahren kombiniert die Vakuumtherapie mit der automatisierten, kontrollierten Zufuhr und Drainage wirkstoffhaltiger Lösungen zur topischen Wundbehandlung im Wundbett und auch wirkstofffrei durch Instillation physiologischer Kochsalzlösung (Unterdruck-Instillationstherapie). Hierdurch können die Effekte der konventionellen Vakuumtherapie mit denen der lokalen Antisepsis kombiniert werden. Hierdurch kommt es zu einer Reduktion der Wundfläche, einer Induktion von Granulationsgewebe sowie einer Reduktion der Keimbesiedelung der Wunden. Bisher publizierte Studien konzentrieren sich auf die Anwendung dieses Therapieverfahrens zur Behandlung orthopädisch-chirurgischer Krankheiten. Die Datenlage bezüglich der Vakuum-Instillationstherapie in der Dermatochirurgie beschränkt sich derzeit auf Fallberichte und Einzelfallerfahrungen. Randomisierte, prospektive Studien zum Vergleich der Vakuum-Instillationstherapie zur Behandlung dermatologischer Krankheitsbilder existieren bislang nicht. Ziele des vorliegenden Artikels sind die Vorstellung der Vakuumtherapie mit Instillation einschließlich ihres Wirkprinzips, deren mögliche Komplikationen, die Diskussion erdenklicher Kontraindikationen sowie eine Übersicht über die aktuell verfügbare Datenlage. Zusammenfassend scheint sich die Evidenz zu verdichten, dass mittels Unterdruck-Instillationstherapie sowohl einfache als auch komplizierte Wunden effizient behandelt werden können, was sich in einer deutlichen Beschleunigung der Wundgranulation mit konsekutiv früher möglichem Defektverschluss äußert. PMID:27509413

  10. TÜV - Zertifizierungen in der Life Science Branche

    NASA Astrophysics Data System (ADS)

    Schaff, Peter; Gerbl-Rieger, Susanne; Kloth, Sabine; Schübel, Christian; Daxenberger, Andreas; Engler, Claus

    Life Sciences [1] (Lebenswissenschaften) sind ein globales Innovationsfeld mit Anwendungen der Bio- und Medizinwissenschaften, der Pharma-, Chemie-, Kosmetik- und Lebensmittelindustrie. Diese Branche zeichnet sich durch eine stark interdisziplinäre Ausrichtung aus, mit Anwendung wissenschaftlicher Erkenntnisse und Einsatz von Ausgangsstoffen aus der modernen Biologie, Chemie und Humanmedizin sowie gezielter marktwirtschaftlich orientierter Arbeit.

  11. Brennraumdruckregelung von Dieselmotoren mit homogener Kompressionszündung (HCCI)

    NASA Astrophysics Data System (ADS)

    Kohlhase, Martin

    In den letzten Jahren ist die Zahl der neu zugelassenen Dieselfahrzeuge stark gestiegen. Diese Entwicklung ist zum einen darauf zurückzuführen, dass der Dieselmotor im Vergleich zum Ottomotor einen besseren thermischen Wirkungsgrad aufweist. Einhergehend damit ist der Kraftstoffverbrauch und somit der CO2-Ausstoß im Gegensatz zum Ottomotor deutlich geringer. Zum anderen hat der Dieselmotor im Bereich Fahrspaß und -komfort durch Einzug der Direkteinspritzung basierend auf Common-Rail-Systemen und durch effiziente Abgasturbolader mit variabler Turbinengeometrie (VTG) deutlich an Akzeptanz gewonnen.

  12. Abdichtungen im Verbund mit Fliesen und Platten

    NASA Astrophysics Data System (ADS)

    Platts, Thomas

    Abdichtungen im Verbund mit Fliesen und Platten, im Folgenden auch als Verbundabdichtungen oder mit Kurzzeichen als AIV bezeichnet, haben sich in der Baupraxis insbesondere in Innenräumen wegen des vereinfachten konstruktiven Aufbaus gegenüber Bahnenabdichtungen nach DIN 18195-5 [14.1] in der Mehrzahl der Ausführungen durchgesetzt und bewährt. Sie können im Innen- und Außenbereich angeordnet werden und sind dadurch gekennzeichnet, dass die Nutzschicht in Boden- und Wandbereichen im Dünnbettverfahren unmittelbar auf die Abdichtung aufgebracht wird. Aufwändige Zwischenschichten oder Einbauteile wie armierter Putz, Telleranker etc. entfallen (Bild 14.1) und es lassen sich geringere Aufbauhöhen realisieren.

  13. Historisches Rätsel Der rastlose Amerikaner

    NASA Astrophysics Data System (ADS)

    Loos, Andreas

    2004-09-01

    In der Schule, die er mit acht Jahren zum ersten Mal von innen sah, hielt man ihn nicht für allzu helle - schließlich hinkte der Kleine oft hinter der Klasse her. Und es hat etwas Tragisches, wenn der wohl berühmteste Erfinder aller Zeiten und Halter von 2000 Patenten im Alter über seinen Vater sagt: Er dachte, ich sei dumm. Und ich meinte schon fast selbst, ich sei ein Dummkopf.

  14. Grundlegende Steuerungsverfahren im heterogenen Logistiknetz mit Kanban

    NASA Astrophysics Data System (ADS)

    Dickmann, Eva; Dickmann, Philipp; Lödding, Hermann; Möller, Niklas; Rücker, Thomas; Schneider, Herfried M.; Zäh, Michael F.

    In vielen Unternehmen werden heterogene (verschiedene) Steuerungen in einem abgestimmten Konzept kombiniert. Je nach Anwendungsfall und Rahmenbedingungen werden Kombinationen allgemein bekannter Steuerungen oder Steuerungsvarianten gemischt eingesetzt, um eine optimale Steuerung für unterschiedliche Fälle zu erreichen. Hierbei stehen neben den bekannten und weit verbreiteten Methoden, wie Material Requirements Planning (MRP) oder Kanban, auch weniger bekannte oder neue Methoden zur Auswahl, wie die Produktionssteuerung mit dezentraler, bestandsorientierter Fertigungsregelung (DBF). Kanban ist ein simples und effizientes Steuerungskonzept, das in der klassischen Form für spezifische einfache Anwendungsfälle umsetzbar ist. Hochentwickelte Steuerungsalgorithmen können helfen, komplexe Abläufe optimal abzubilden. Mit einer grundlegenden Vereinfachung der Abläufe kann allerdings in vielen Fällen ein wesentlich stärkerer und umfassender Verbesserungseffekt erzielt werden. Die wesentliche Fragestellung sollte folglich lauten: Warum ist der Ablauf nicht mit einer einfachen Steuerung wie Kanban abzubilden? Um die Vorteile des Konzepts auch in untypischen Bereichen anwenden zu können, sind jedoch verschiedene Varianten oder Kanban-ähnliche Steuerungsmethoden entstanden. Darüber hinaus sind in der Praxis hybride Steuerungen im Einsatz, welche so kombiniert werden, dass die Zusammensetzung anspruchsvolle Eigenschaftsbilder noch exakt abbildet. In der Praxis basieren die Steuerungsentscheidungen nur zu einem kleinen Teil auf den eigentlichen Steuerungsalgorithmen, wie sie uns das MRP-System zur Verfügung stellt. Moderne Steuerungswelten" schließen alle relevanten Informationsquellen in eine heterogene Entscheidungsmatrix mit ein. Letztlich zählt nicht, ob die Entscheidung auf den Informationen aus dem MRP-System oder auf Softfacts basierend getroffen wurde, sondern nur, ob die Entscheidung erfolgreich war.

  15. MIT: Shaping the Future.

    ERIC Educational Resources Information Center

    Manning, Kenneth R., Ed.

    This book provides 16 essays by faculty and staff of the Massachusetts Institute of Technology (MIT) concerning what MIT is like today and offering a guide to its possible future. Emphasis is placed on local, national, and global issues, providing a current sampling of the state of concerns and opinions around MIT. Topics include the question of…

  16. Biochips und ihr Einsatz in der Lebensmittelanalytik

    NASA Astrophysics Data System (ADS)

    Huber, Ingrid; Zeltz, Patric

    Mit der Verbreitung des Begriffes "Biochip“ in den biotechnologischen Medien wurde Ende der 1990er-Jahre zunächst der Eindruck erweckt, dass die Computerelektronik in die molekularbiologischen Anwendungen eingestiegen ist [18]. In nur wenigen Jahren hat sich die Biochiptechnologie zu einem Verfahren entwickelt, das aus der molekularbiologischen Grundlagenforschung nicht mehr wegzudenken ist und über eine Vielzahl von Einsatzbereichen verfügt. Die Biochiptechnologie ermöglicht die Miniaturisierung von DNA-, RNA- bzw. Proteinanalytik in hochparallelen Formaten. Dieser hohe Parallelisierungsgrad ist einer der wesentlichen Vorteile dieser Technik gegenüber klassischen molekularbiologischen Methoden. Sie wird heutzutage vor allem in der Genomforschung eingesetzt, für Genexpressionsstudien, zum Screening von single nucleotide polymorphisms (SNPs), in der pharmakogenetischen Forschung sowie in der Erforschung von Erbkrankheiten und in der Krebsforschung [1, 7, 19]. Neben vielen weiteren Bereichen finden Biochips auch spezielle Anwendungen in der Lebensmittelanalytik.

  17. Sterblichkeit: der paradoxe Kunstgriff des Lebens - Eine Betrachtung vor dem Hintergrund der modernen Biologie

    NASA Astrophysics Data System (ADS)

    Verbeek, Bernhard

    Leben gibt es auf der Erde seit fast 4 Mio. Jahren, trotz allen Katastrophen. Die Idee des Lebens scheint unsterblich. Der Tod aber offenbar auch. Jedes Lebewesen ist davon bedroht, ja für Menschen und andere "höhere“ Lebewesen ist er im Lebensprogramm eingebaut - todsicher. Diese Tatsache ist alles andere als selbstverständlich. Ist sie überhaupt kompatibel mit dem Prinzip der Evolution, nach dem der am besten Angepasste überlebt?

  18. Jahr der Geowissenschaften

    NASA Astrophysics Data System (ADS)

    Wohnlich, Stefan

    2002-06-01

    Das System Erde ist Leitthema des "Jahres der Geowissenschaften", das von der Bundesministerin für Bildung und Forschung in den Vordergrund der Initiative "Wissenschaft im Dialog" für 2002 gestellt wurde. Es soll aufzeigen, dass wir in einer empfindlichen Umwelt leben, die auf die natürlichen Schwankungen, z. B. des Klimas, genauso empfindlich reagiert wie auf die rücksichtslose Nutzung der Erde durch den Menschen. Damit rückt auch das Thema Grundwasser als Teil des globalen Wasserkreislaufes in den Mittelpunkt der derzeitigen Öffentlichkeitsarbeit. Wenn wir uns die bisherige Resonanz auf das Jahr der Geowissenschaften anschauen, dann ist festzustellen, dass gerade die Bereitschaft aus den Medien zur Aufnahme von Geowissenschaftlichen Themen erstaunlich groß ist. Aus dem Bereich des Grund- und Trinkwassers snd vor allem in Universitätsstädten bereits größere Veranstaltungen durchgeführt worden oder stehen noch im Laufe des Jahres aus (Information unter: www.planeterde.de). Tatsächlich ist der Dialog von Wissenschaft und Praxis mit der Öffentlichkeit ein vorrangiges Ziel auch der Fachsektion Hydrogeologie. Nur allzu leicht tritt dieses Ziel im Alltagsbetrieb in den Hintergrund. Die deutschen Universitäten und Wissenschaftsorganisationen haben in die Öffentlichkeitsarbeit erst in den letzten Jahren verstärkt Ideen und Mittel investiert. Dabei ist gerade das Verständnis für die Chancen und Risiken der Forschung und damit auch der Hochschullehre in der breiten Öffentlichkeit eine unabdingbare Voraussetzung. Aber nicht nur die wissenschaftliche Organisationen sind auf die Akzeptanz einer breiten Öffentlichkeit für wissenschaftlich fundiertes Arbeiten angewiesen, sondern auch die von Fachwissen geprägten Aufgaben im Umfeld des Grundwassers brauchen das Verständnis für ihre oft aufwändigen Untersuchungen. Ich habe in den letzten Monaten mehrere Vorträge an verschiedenen Gymnasien zum Thema "Ressource Grundwasser" gehalten. Die Resonanz war f

  19. Jahre Entwicklung der Instandhaltung - von der ausfallorientierten Instandhaltung zum gemeinsamen TPM und RCM

    NASA Astrophysics Data System (ADS)

    Iske, Friedhelm

    Zur Einleitung meines Beitrages möchte ich von einem Gespräch mit einem Mitarbeiter berichten, das ich als junger Vorgesetzter einer Instandhaltungsgruppe 1988 führte. Der engagierte Mitarbeiter feierte damals sein vierzigjähriges Dienstjubiläum und war stolz auf das von ihm Geleistete sowie auf den besonderen Einsatz seiner Altersgruppe, die nach dem Zweiten Weltkrieg das Werk wieder aufgebaut hatte. Auf meine Frage, was denn damals die erste Aufgabe in der Firma war, bekam ich kurz und knapp und mit einer Selbstverständlichkeit die selbstbewusste Antwort: "Unser Pferd füttern und mit dem Pferd die innerbetrieblichen Transporte erledigen“. Als junger, technisch orientierter Vorgesetzter war ich über diese Antwort sehr überrascht. Gedanklich weit entfernt war die Vorstellung, dass in der Vergangenheit Transporte mit einem Pferd erledigt wurden.

  20. Akteure in der Renaturierung

    NASA Astrophysics Data System (ADS)

    Wiegleb, Gerhard; Lüderitz, Volker

    Dieses Kapitel behandelt die Bedeutung von Akteuren in Renaturierungsprojekten. Renaturierung ist die absichtliche Veränderung der Umwelt in Richtung auf einen von den Akteuren als "naturnäher“ erachteten Zustand (Kapitel 1). Betroffen davon ist nicht nur die Umwelt der Akteure, sondern auch die Umwelt anderer. Daraus ergeben sich sowohl aktive wie passive Bezüge zur Renaturierung. Aktive und passive Rollen sind je nach Ausdehnung, Zeithorizont und Trägerschaft nicht immer trennbar, sodass die Unterscheidung in Akteure und Betroffene nur begrenzte Gültigkeit hat. Methodisch basiert die Untersuchung der Teilhabe an Renaturierung auf Akteurs- und Akzeptanzanalysen (vgl. Segert und Zierke 2004, Newig 2004). Die vorliegenden Ausführungen befassen sich schwerpunktmäßig mit dem Aspekt der Akteursanalyse. Die Frage der Akzeptanz wird kurz angesprochen (Kapitel 15, Umweltethische Aspekte). Anhand der Analyse zweier Fallstudien werden dann einige Schlussfolgerungen gezogen. Die Darstellung soll im Wesentlichen das Feld für zukünftig nötige Forschungsarbeiten strukturieren.

  1. Entwicklung und methodische Verbesserung der Arbeitssicherheit in der Instandhaltung

    NASA Astrophysics Data System (ADS)

    Galinski, Marek

    Die Hüttenwerke Krupp Mannesmann gehören zu den führenden Stahlherstellern in Europa. Die Instandhaltung ist einerseits den Anlagen vor Ort zugeordnet, andererseits gibt es für werksweite bzw. spezielle Themen eine zentrale Instandhaltung. Die im Folgenden beschriebenen Methoden wurden für das gesamte Unternehmen entwickelt, jedoch je nach Organisationseinheit unterschiedlich adaptiert und unterschiedlich intensiv verfolgt. Die zentrale Instandhaltung hat insbesondere in den letzten 12 Jahren der Arbeitssicherheit einen hohen Stellenwert beigemessen, und hervorragende Ergebnisse erzielt. So ist die Unfallhäufigkeit in der zentralen Instandhaltung von ca. 30 anzeigepflichtigen Unfällen pro eine Million verfahrener Stunden vor ca. 15 Jahren auf Null in 2007 gesunken! In 2008 konnte dieses hervorragende Ergebnis gehalten werden. Zwei Jahre unfallfrei! Wer hätte das vor 15 Jahren gedacht? Der Schwerpunkt des Beitrags liegt auf der Erläuterung der Ansatzpunkte mit denen dieses Ergebnis erreicht wurde und der Darstellung der Methoden incl. der Anpassung an die veränderten Ansatzpunkte in den betroffenen Bereichen. Die beschriebenen Methoden sind in der zentralen Instandhaltung so angewendet worden.

  2. VDI-Richtlinien - mit Technischen Regeln Wirtschaftlichkeit erhöhen und Standards setzen

    NASA Astrophysics Data System (ADS)

    Mandelartz, Johannes

    Der Verein Deutscher Ingenieure e.V. (VDI) ist ein gemeinnütziger, wirtschaftlich und politisch unabhängiger, technisch-wissenschaftlicher Verein von Ingenieuren und Naturwissenschaftlern. Mit über 137 000 persönlich zugeordneten Mitgliedern ist er eine der größten Ingenieur-Vereinigungen Europas und gilt in Deutschland als führender Sprecher der Technik und der Ingenieure. 1856 gegründet, hat er viele für die Technik wesentliche Entwicklungen in Gang gesetzt, so im Bereich der technischen Überwachung, der technischen Regelsetzung und Normung, der Arbeitsstudien, im gewerblichen Rechtsschutz und im Patentwesen. Seit seiner Gründung sieht es der VDI als seine Aufgabe, "das Zusammenwirken aller geistiger Kräfte der Technik im Bewusstsein ethischer Verantwortung zu fördern“ und die Lebensmöglichkeiten aller Menschen durch Entwicklung und sinnvoller Anwendung technischer Mittel zu verbessern.

  3. E-Learning an der TUM: Entwicklung - Status Quo - Perspektiven

    NASA Astrophysics Data System (ADS)

    Stross, Manfred; Baume, Matthias; Schulze, Elvira

    E-Learning an der Technischen Universität München (TUM) hat sich ähnlich wie an den meisten anderen Hochschulen als ein wesentliches Element der Hochschullehre etabliert. Seit mehr als einem Jahrzehnt werden in diesem Themenfeld Erfahrungen gesammelt und Entwicklungen vorangetrieben. Der Artikel beschäftigt sich zunächst mit E-Learning aus einer allgemeinen Perspektive und greift unterschiedliche Entwicklungsphasen der vergangenen Jahre auf. Im Anschluss daran wird der Fokus auf die TUM gesetzt. Der Beitrag zeigt die spezifische Entwicklung von E-Learning im Verlauf der vergangenen Jahre auf, nennt Funktionen und Verfahren von E-Learning und beschreibt Zielsetzungen für E-Learning an der TUM. Im Anschluss daran wird die aktuelle Situation anhand verschiedener Perspektiven analysiert. Den Abschluss des Beitrags bilden die Darstellung der zukünftigen Herausforderungen von E-Learning an der TUM und ein Ausblick auf weitere Entwicklungen.

  4. Materialbereitstellung in der Montage

    NASA Astrophysics Data System (ADS)

    Nyhuis, Peter; Wiendahl, Hans-Peter; Fiege, Torsten; Mühlenbruch, Helge

    Die Montage verarbeitet eine sehr große Anzahl unterschiedlicher Teile und Baugruppen in zahlreichen Varianten. Sie müssen mit hoher Zuverläs-sigkeit am richtigen Ort zur richtigen Zeit in der richtigen Qualität and zu den richtigen Kosten bereit stehen. Im Gegensatz zum Ausgangsmaterial in einer Fertigung sind sie funktionsfähig and damit meist empfindlich. Bevor sie an einer Montageeinrichtung eintreffen, sind auf dem Wege vom Hersteller zum Verbauort drei unterschiedliche Abschnitte zu erkennen, die von unterschiedlichen inner- und außerbetrieblichen Akteuren geplant, durchgeführt and überwacht werden.

  5. Symmetriebrechung und Emergenz in der Kosmologie.

    NASA Astrophysics Data System (ADS)

    Mainzer, K.

    Seit der Antike wird der Aufbau des Universums mit einfachen und regulären (symmetrischen) Grundstrukturen verbunden. Diese Annahme liegt selbst noch den Standardmodellen der relativistischen Kosmologie zugrunde. Demgegenüber läßt sich die Emergenz neuer Strukturen von den Elementarteilchen über Moleküle bis zu den komplexen Systemen des Lebens als Symmetriebrechung verstehen. Symmetriebrechung und strukturelle Komplexität bestimmen die kosmische Evolution. Damit zeichnet sich ein fachübergreifendes Forschungsprogramm von Physik, Chemie und Biologie ab, in dem die Evolution des Universums untersucht werden kann.

  6. [Beweggründe von Krebspatienten für und gegen die Inanspruchnahme der Misteltherapie].

    PubMed

    Gschwendtner, Kathrin M; Holmberg, Christine; Weis, Joachim

    2016-01-01

    Einleitung: Die Misteltherapie ist im deutschsprachigen Raum ein häufig angewandtes komplementärmedizinisches Verfahren (KM) in der Onkologie. Diese Studie hatte das Ziel, die Beweggründe für oder gegen eine Inanspruchnahme der Misteltherapie zu untersuchen und Themenfeldern zuzuordnen. Patienten und Methoden: Es wurden qualitative leitfadengestützte Interviews mit Krebspatienten geführt. Der Interviewleitfaden fragte nach der Inanspruchnahme von KM, der Motivation zur Inanspruchnahme, Informationsverhalten und -bedürfnissen zu KM sowie nach der Krebserkrankung. Um die Beweggründe für die Inanspruchnahme oder Nichtinanspruchnahme der Misteltherapie zu verstehen, wurden die Interviews inhaltsanalytisch ausgewertet. Ergebnisse: Insgesamt wurden Interviews mit 88 Krebspatienten geführt, davon nutzen 18 (20,5%) die Misteltherapie. Die Beweggründe für oder gegen eine Inanspruchnahme der Misteltherapie ließen sich den 2 Themenfeldern «Wahrgenommene Indikation» und «Abwägungen bei der Entscheidungsfindung» zuordnen. Diskussion und Schlussfolgerungen: Mit der Misteltherapie wird sowohl ein Einfluss auf das Tumorwachstum als auch eine supportive Wirkung assoziiert. Anwender sehen die Misteltherapie als sicheres Verfahren; Nichtnutzer befürchten eher Neben- oder Wechselwirkungen. Die Empfehlung von Fachpersonal spielt eine wichtige Rolle bei der Inanspruchnahme. Zum Teil waren die Nichtnutzer interessiert an der Anwendung der Misteltherapie, befanden sich jedoch noch im Klärungsprozess.

  7. [Beweggründe von Krebspatienten für und gegen die Inanspruchnahme der Misteltherapie].

    PubMed

    Gschwendtner, Kathrin M; Holmberg, Christine; Weis, Joachim

    2016-01-01

    Einleitung: Die Misteltherapie ist im deutschsprachigen Raum ein häufig angewandtes komplementärmedizinisches Verfahren (KM) in der Onkologie. Diese Studie hatte das Ziel, die Beweggründe für oder gegen eine Inanspruchnahme der Misteltherapie zu untersuchen und Themenfeldern zuzuordnen. Patienten und Methoden: Es wurden qualitative leitfadengestützte Interviews mit Krebspatienten geführt. Der Interviewleitfaden fragte nach der Inanspruchnahme von KM, der Motivation zur Inanspruchnahme, Informationsverhalten und -bedürfnissen zu KM sowie nach der Krebserkrankung. Um die Beweggründe für die Inanspruchnahme oder Nichtinanspruchnahme der Misteltherapie zu verstehen, wurden die Interviews inhaltsanalytisch ausgewertet. Ergebnisse: Insgesamt wurden Interviews mit 88 Krebspatienten geführt, davon nutzen 18 (20,5%) die Misteltherapie. Die Beweggründe für oder gegen eine Inanspruchnahme der Misteltherapie ließen sich den 2 Themenfeldern «Wahrgenommene Indikation» und «Abwägungen bei der Entscheidungsfindung» zuordnen. Diskussion und Schlussfolgerungen: Mit der Misteltherapie wird sowohl ein Einfluss auf das Tumorwachstum als auch eine supportive Wirkung assoziiert. Anwender sehen die Misteltherapie als sicheres Verfahren; Nichtnutzer befürchten eher Neben- oder Wechselwirkungen. Die Empfehlung von Fachpersonal spielt eine wichtige Rolle bei der Inanspruchnahme. Zum Teil waren die Nichtnutzer interessiert an der Anwendung der Misteltherapie, befanden sich jedoch noch im Klärungsprozess. PMID:27606463

  8. Checkpoint-Inhibitoren in der Immuntherapie: Ein Meilenstein in der Behandlung des malignen Melanoms.

    PubMed

    Wilden, Sophia M; Lang, Berenice M; Mohr, Peter; Grabbe, Stephan

    2016-07-01

    Seit Jahrzehnten ist bekannt, dass Tumoren vom Immunsystem erkannt und zerstört werden können. Diese, vor allem in Tierversuchen gewonnene Erkenntnis konnte jedoch in der Vergangenheit nicht zum Nutzen unserer Patienten umgesetzt werden, da immunonkologische Therapieansätze in den letzten Jahrzehnten in der Anwendung beim Menschen stets versagt haben. Daher hat, mit Ausnahme der adjuvanten Interferontherapie, keines dieser Verfahren den Einzug in die klinische Versorgung gefunden. Langzeitüberleben unter guter Lebensqualität war dabei sehr wenigen Patienten vorbehalten. Mit den neuen immunologischen Therapieansätzen wird jedoch sowohl das Langzeitüberleben als auch die Lebensqualität onkologischer Patienten neu definiert. Auf die neuen "Immun-Checkpoint-Inhibitoren" spricht erstmals ein relevanter Teil der behandelten Patienten an und diese zeigen in der Regel langandauernde Remissionen bis hin zur Heilung. Schon jetzt ist klar, dass die Immuntherapie in Zukunft eine der wesentlichen Therapiesäulen bei der Behandlung des metastasierten Melanoms und auch vieler anderer fortgeschrittener Tumoren bilden wird. In dieser Übersicht werden die wichtigsten neuen Therapiemodalitäten besprochen und sowohl deren Wirkprinzip als auch klinische Daten zum Therapieansprechen und zu erwartenden Nebenwirkungen der Therapie referiert. PMID:27373243

  9. Unfälle mit Kleintransportern

    NASA Astrophysics Data System (ADS)

    Tschirschwitz, Christian

    Auf einer außerörtlichen Bundesstraße geriet ein mit vier Personen besetzter Pkw Toyota Corolla aus letztlich nicht vollständig geklärten Gründen ins Schleudern. Nachdem sich das Fahrzeug beträchtlich entgegen dem Uhrzeigersinn ausgedreht hatte, prallte ein entgegenkommender Kleintransporter VW T4 frontal an die rechte Flanke des Toyota. Der Transporter wurde gedreht, ausgehoben und durch einen Pkw Ford Escort unterfahren. Alle Fahrzeuge kamen in Kollisionsortnähe zum Endstand. Die vier Toyota-Insassen wurden getötet. Aus den anderen Fahrzeugen wurden sechs Personen überwiegend schwer verletzt. Unbeteiligte Zeugen waren nicht vorhanden.

  10. Endoskopie, minimal invasive chirurgische und navigierte Verfahren in der Urologie

    NASA Astrophysics Data System (ADS)

    Grosse, Joachim; von Walter, Matthias; Jakse, Gerhard

    Betrachtet man die letzten 100 Jahre der Urologie in Deutschland seit Gründung ihrer Fachgesellschaft 1906 in Stuttgart, so sind sicherlich die letzten 25 Jahre von umfassenden Entwicklungen mit z. T. vollständigen Umwälzungen bisheriger Therapien und Methoden auf urologischen Fachgebiet gekennzeichnet. In erster Linie handelte es sich dabei um minimal invasive endoskopische Techniken wie perkutane Nierenchirurgie, Ureterorenoskopie, videoendoskopisch unterstütze transurethrale Elektroresektionen der Prostata und von Blasentumore sowie die Laparoskopie. Sie führten zu besseren operativen Ergebnissen und einer deutlichen Senkung der Morbidität der entsprechenden Behandlung urologischer Krankheitsbilder, mit der Konsequenz, dass einige bisher als Standard gültige offene Operationsverfahren abgelöst wurden.

  11. Vollautomatische Segmentierung der Prostata aus 3D-Ultraschallbildern

    NASA Astrophysics Data System (ADS)

    Heimann, Tobias; Simpfendörfer, Tobias; Baumhauer, Matthias; Meinzer, Hans-Peter

    Diese Arbeit beschreibt ein modellbasiertes Verfahren zur Segmentierung der Prostata aus 3D-Ultraschalldaten. Kern der Methode ist ein statistisches Formmodell, das auf Beispieldaten der Prostata trainiert wird. Erster Schritt der Segmentierung ist ein evolutionärer Algorithmus, mit dem das Modell grob im zu segmentierenden Bild positioniert wird. Für die darauf folgende lokale Suche wurden mehrere Varianten des Algorithmus evaluiert, unter anderem Ausreißer-Unterdrückung, freie Deformation und Gewichtung der verwendeten Erscheinungsmodelle nach ihrer Zuverlässigkeit. Alle Varianten wurden auf 35 Ultraschallbildern getestet und mit manuellen Referenzsegmentierungen verglichen. Die beste Variante erreichte eine durchschnittliche Oberflächenabweichung von 1.1 mm.

  12. Bewertung von Fahrerassistenzsystemen mittels der Vehicle in the Loop-Simulation

    NASA Astrophysics Data System (ADS)

    Bock, Thomas

    Mit der Vehicle in the Loop-Simulation hat Audi eine Test- und Simulationsumgebung für Fahrerassistenzsysteme entwickelt, welche die Vorzüge eines realen Versuchsfahrzeugs mit der Sicherheit und Reproduzierbarkeit von Fahrsimulatoren kombiniert. Virtueller Fremdverkehr, Straßenbegrenzungen oder sonstige simulierte Gegenstände werden durch ein "Optical see through Head Mounted Display“ während der Fahrt realitätsnah und kontaktanalog für den Fahrer eingeblendet. Besonders bei der Erprobung aktiver Fahrerassistenzsysteme eröffnen sich durch das Konzept des virtuellen Fremdverkehrs im realen Versuchsfahrzeug neue Möglichkeiten.

  13. Die qualitätskontrolle als hilfsmittel zur festlegung der produktionsparameter bei der herstellung von lwr-brennstoffen

    NASA Astrophysics Data System (ADS)

    Sondermann, T.

    1982-04-01

    ZusammenfassungDer bekannte Vorteil des AUC-Verfahrens, ein UO 2-Pulver zu liefern, das ohne Zwischenschritte direkt zu Tabletten verpreβt werden kann, geht mit einer weiteren, weniger bekannten positiven Eigenschaft einher: Mit der Wahl der Produktionsparameter bei der UO 2-Pulverherstellung können die Qualitätsmerkmale der Brennstofftabletten direkt gesteuert werden. Wie umfangreiche Untersuchungen gezeigt haben, besteht ein mathematisch formulierbarer Zusammenhang zwischen den Produktionsparametern und den Pulver-bzw. Tablettenqualitäten. Das so erhaltene mathematische Modell gestattet es nun, exakt die Produktionsparameter einzustellen, die zur gewünschten Qualität führen, wobei gleichzeitig die wirtschaftliche Fahrweise gewählt werden kann.

  14. [Evaluation of the Musical Concentration Training with Pepe (MusiKo mit Pepe) for children with attention deficits].

    PubMed

    Rothmann, Kathrin; Hillmer, Jana-Mareike; Hosser, Daniela

    2014-09-01

    Fragestellung: Die vorliegende Studie überprüft die Wirksamkeit des Musikalischen Konzentrationstrainings mit Pepe (MusiKo mit Pepe) für fünf- bis zehnjährige Kinder mit Aufmerksamkeitsproblemen. Methodik: In einem Prä-Post-Kontrollgruppendesign (N = 108) wurden Veränderungen der Aufmerksamkeitsleistung mittels der Testbatterie zur Aufmerksamkeitsprüfung für Kinder (KiTAP) sowie Veränderungen der kindlichen Lebensqualität mittels des Fragebogens für Kinder (KINDL-R) erfasst. Zusätzlich wurden Fremdbeurteilungsbögen zur Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung (FBB-ADHS) sowie zur Störung des Sozialverhaltens (FBB-SSV) des Diagnostik-Systems für psychische Störungen nach ICD-10 und DSM-IV für Kinder und Jugendliche II und der Eltern- und der Lehrerfragebogen über das Verhalten von Kindern und Jugendlichen (CBCL, TRF) eingesetzt. Ergebnisse: Es zeigen sich für die am Training teilnehmenden Kinder im Vergleich zu der Kontrollgruppe über die Zeit signifikante Verbesserungen der Aufmerksamkeitsleistung sowie der Lebensqualität. Darüber hinaus ergibt sich eine signifikante Reduktion der ADHS-Symptomatik im Eltern- und Lehrerurteil sowie eine Verminderung der Internalisierenden Probleme im Elternurteil. Die Behandlungseffektivität ist unabhängig von Alter, Geschlecht, Intelligenz und Migrationshintergrund der teilnehmenden Kinder. Schlussfolgerung: Das musikbasierte Trainingsprogramm MusiKo mit Pepe stellt eine wirkungsvolle Maßnahme zur Behandlung von Aufmerksamkeitsproblemen dar, sollten sich diese Effekte in Replikationsstudien bestätigen.

  15. Kanban - der Weg ist das Ziel

    NASA Astrophysics Data System (ADS)

    Aull, Florian; Berlak, Joachim; Dickmann, Eva; Dickmann, Philipp; Fischäder, Holm; Gerlach, Joachim; Henneberg, Jens; Kapalla, Klaus; Kress, Oliver; Kuttler, Robert; Schneider, Herfried M.; Schürle, Philipp; Stellpflug, Franz-Josef; Wannenwetsch, Ralph; Wulz, Johannes; Zäh, Michael F.

    Wenn man aktuell Produktionsbereiche in Deutschland und Europa besucht, fallen im Zusammenhang mit modernen Produktionsmethoden immer öfter die Begriffe Kanban (jap. Karte, Signal) und Pull-Produktion, und dies nicht ohne Stolz, da diese mit dem schillernden Vorbild des Toyota Produktionssystems in Zusammenhang stehen. Tatsächlich ist Kanban ein integraler Bestandteil moderner Produktionssysteme. Blickt man aber im Rahmen von Prozessanalysen hinter die Fassaden", d. h. in die tägliche Praxis der Arbeitsprozesse, wird man schnell desillusioniert - die viel gepriesenen klassischen Kanban-Regeln werden im Tagesgeschäft nicht eingehalten.

  16. Tycho Brahe - Instrumentenbauer und Meister der Beobachtungstechnik

    NASA Astrophysics Data System (ADS)

    Wolfschmidt, Gudrun

    Vor der Erfindung des Fernrohrs war der dänische Astronom Tycho Brahe (1546 - 1601) der bedeutendste beobachtende Astronom. Von seinem Observatorium Uraniborg auf der - damals dänischen - Insel Hven ist heute noch der Grundriß erkennbar, von Stjerneborg sind die Fundamente erhalten, die Kuppeln in den 1950er Jahren ergänzt. In der Astronomie-Ausstellung im Deutschen Museum gibt es ein Modell der Sternwarte Uraniborg und der zugehörigen Instrumente (Maßstab 1:10); das größere Modell wurde dem Technischen Museum in Malmö geschenkt. Die Instrumente, die er in den Observatorien Uraniborg und Stjerneborg benutzte, sind nicht erhalten. Aber es gibt gute Beschreibungen der Instrumente (Halbkreis, Quadranten, Sextanten, Armillarsphären, Triquetrum, Himmelsglobus) in seinem Buch Astronomiae instauratae mechanica (Wandsbek 1598). Eine Nachbildung des großen hölzernen Quadranten kann man im Runden Turm in Kopenhagen sehen. Zwei Sextanten, hergestellt für Tycho um 1600 von Jost Bürgi und Erasmus Habermel, gibt es noch im Nationalmuseum für Technik in Prag. Ähnlichkeiten von Tychos Instrumenten mit Groß-Instrumenten aus dem islamischen Kulturkreis sind auffällig. Tycho Brahes Meßgeräte markieren einen großen Fortschritt in der Entwicklung astronomischer Instrumente und Meßtechniken und bilden die Grundlage für den weiteren Fortschritt der Positionsastronomie und der damit verbundenen Tabellenwerke. Die Nachwirkungen sind bis ins 17. und 18. Jahrhundert nachweisbar.

  17. [COPD und Klangtherapie: Pilotstudie zur Wirksamkeit einer Behandlung mit Körpertambura bei COPD-Patienten].

    PubMed

    Hartwig, Bernhard; Schmidt, Stefan; Hartwig, Isabella

    2016-01-01

    Hintergrund: Erkrankungen der Atemorgane treten mit steigendem Alter öfter auf, nehmen weltweit zu und sind häufige Ursachen für Morbidität und Mortalität. In dieser Pilotstudie wurde der Frage nachgegangen, ob eine einmalige 10-minütige Behandlung mit einer Körpertambura eine signifikante und effektive Verbesserung der Lungenfunktion von Patienten mit chronisch-obstruktiver Lungenerkrankung (COPD; GOLD-Stadium A oder B) erbringen kann. Patienten und Methoden: 54 Probanden konnten je zur Hälfte in eine Behandlungsgruppe (Körpertambura) und eine aktive Kontrollgruppe (Atemtherapie) randomisiert werden. Eine Bestimmung der Lungenfunktionsmessparameter «Einsekundenkapazität» (FEV1) und «inspiratorische Vitalkapazität» (IVC) zu den Zeitpunkten T1 (Baseline), T2 (direkt nach Behandlung) und als Follow-up etwa 3 Wochen nach T1 (T3). Ergebnisse: Die Behandlungsgruppe zeigte sich der Kontrollgruppe in beiden Werten signifikant überlegen. Die Zeit-×-Gruppe-Interaktion (Varianzanalyse) ergab p = 0,001 (FEV1) bzw. p = 0,04 (IVC). Die Behandlungsgruppe zeigte bei beiden Werten eine Verbesserung von klinischer Relevanz. Schlussfolgerung: Diese Ergebnisse zeigen, dass die Klangbehandlung mittels einer Körpertambura - neben den schulmedizinischen, leitliniengerechten Therapien - eine zusätzliche, nebenwirkungsarme, aber durchaus klinisch wirksame Option für die Behandlung von COPD-Patienten darstellen kann, um deren Lebensqualität zu stabilisieren und zu verbessern. PMID:27606616

  18. Verbesserung der Prozessbedingungen beim Einlippentiefbohren durch unterschiedliche Formen der Vorschubmodulation

    NASA Astrophysics Data System (ADS)

    Eisseler, Rocco

    Das Tiefbohren mit Einlippenwerkzeugen ist bei vielen Anwendungen das Verfahren der ersten Wahl, vor allem wenn kleine und kleinste Bohrungsdurchmesser, ein sehr großes Verhältnis zwischen Bohrtiefe und Durchmesser (l/D) und eine hohe Bearbeitungsqualität gefordert werden. Der erreichbare Durchmesserbereich des Verfahrens liegt zwischen D = 0,5 mm und 40 mm, wobei die möglichen Bohrtiefen von l = 3 x D bis 250 x D reichen. Diese Werte beziehen sich auf das Vollbohren, beim Aufbohren können noch größere Durchmesser erreicht werden [1]. Die erreichbare Oberflächenqualität ist so hoch, dass in den meisten Fällen auf eine nachfolgende Feinbearbeitung verzichtet werden kann.

  19. MIT-CSR XIS Project

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This report outlines the proposers' progress toward MIT's contribution to the X-Ray Imaging Spectrometer (XIS) experiment on the Japanese ASTRO-E mission. The report discusses electrical system design, mechanical system design, and ground support equipment.

  20. MIT research in telerobotics

    NASA Technical Reports Server (NTRS)

    Sheridan, T. B.

    1987-01-01

    Ongoing MIT research in telerobotics (vehicles capable of some autonomous sensing and manipulating, having some remote supervisory control by people) and teleoperation (vehicles for sensing and manipulating which are fully controlled remotely by people) is discussed. The current efforts mix human and artificial intelligence/control. The idea of adjustable impedance at either end of pure master-slave teleoperation, and simultaneous coordinated control of teleoperator/telerobotic systems which have more than six degrees of freedom (e.g., a combined vehicle and arm, each with five or six DOF) are discussed. A new cable-controlled parallel link arm which offers many advantages over conventional arms for space is briefly described. Predictor displays to compensate for time delay in teleoperator loops, the use of state estimation to help human control decisions in space, and ongoing research in supervisory command language are covered. Finally, efforts to build a human flyable real-time dynamic computer-graphic telerobot simulator are described. These projects represent most, but not all, of the telerobotics research in our laboratory, supported by JPL, NASA Ames and NOAA.

  1. Quantenphysikalischer Ursprung der Eichidee

    NASA Astrophysics Data System (ADS)

    Bopp, Fritz

    Betrachtet man die Quantenphysik als Zusammenspiel von elementaren Erzeugungs- und Vernichtungsprozessen, so sind Eichfeldtheorien nicht nur möglich, sondern auch notwendig. Die komplex konjugierten Phasenfaktoren jedes Paares von Erzeugungs- und Vernichtungsoperatoren sind nämlich. willkürlich wählbar. Darum müssen Quantenfeldtheorien vollständig phaseninvariant sein. Das ist ohne Eichfelder nicht möglich.Dem steht im Wege, daß die Diracgleichung nicht einmal global vollständig phaseninvariant ist. Multipliziert man nämlich die Komponenten der Erzeugungs- und Vernichtungsoperatoren mit verschiedenen konstanten Phasenfaktoren, so ändern sich die Diracmatrizen. Nur die Diracschen Vertauschungsrelationen bleiben invariant. Doch sind die Diracgleichungen vor und nach der Transformation physikalisch äquivalent. Man kann also sagen: Systeme freier Fermionen werden erst durch die Klasse aller äquivalenten Diracgleichungen vollständig dargestellt.Da die Diracschen Vertauschungsrelationen gegen beliebige unitäre Transformationen invariant sind, ist die Klasse äquivalenter Diracgleichungen U 4-invariant. Unitäre Diagonalmatrizen liefern willkürliche Phasentransformationen der Spinorkomponenten, so daß die zur Gruppe U 4 gehörigen Eichfelder zu eine allgemein phaseninvarianten Theorie führen. Sie ist so eng mit der QED verwandt, daß wir von einer erweiterten Quantenelektrodynamik, EQE, sprechen können.Hier soll nur gezeigt werden, daß die EQE existiert. Dabei liefert die invariante Untergruppe U 1 von U 4 die QED. Die komplementäre Untergruppe SU 4 umschließt vier Untergruppen SU 3, drei Untergruppen O 4 und sechs Untergruppen SU 2. Letztere könnten den drei Paaren von Quarks und den drei Paaren von Leptonen entsprechen, wobei sich die Quarkpaare zu einer Gruppe SU 3 zusammenschließen. Mehr als zweimal drei Paare von elementaren Fermionen gibt es in der EQE nicht. Sie wird zwar kaum mit der vereinigten QED und QCD identisch sein. Doch sollte sie

  2. MIT's interferometer CST testbed

    NASA Technical Reports Server (NTRS)

    Hyde, Tupper; Kim, ED; Anderson, Eric; Blackwood, Gary; Lublin, Leonard

    1990-01-01

    The MIT Space Engineering Research Center (SERC) has developed a controlled structures technology (CST) testbed based on one design for a space-based optical interferometer. The role of the testbed is to provide a versatile platform for experimental investigation and discovery of CST approaches. In particular, it will serve as the focus for experimental verification of CSI methodologies and control strategies at SERC. The testbed program has an emphasis on experimental CST--incorporating a broad suite of actuators and sensors, active struts, system identification, passive damping, active mirror mounts, and precision component characterization. The SERC testbed represents a one-tenth scaled version of an optical interferometer concept based on an inherently rigid tetrahedral configuration with collecting apertures on one face. The testbed consists of six 3.5 meter long truss legs joined at four vertices and is suspended with attachment points at three vertices. Each aluminum leg has a 0.2 m by 0.2 m by 0.25 m triangular cross-section. The structure has a first flexible mode at 31 Hz and has over 50 global modes below 200 Hz. The stiff tetrahedral design differs from similar testbeds (such as the JPL Phase B) in that the structural topology is closed. The tetrahedral design minimizes structural deflections at the vertices (site of optical components for maximum baseline) resulting in reduced stroke requirements for isolation and pointing of optics. Typical total light path length stability goals are on the order of lambda/20, with a wavelength of light, lambda, of roughly 500 nanometers. It is expected that active structural control will be necessary to achieve this goal in the presence of disturbances.

  3. MIT's interferometer CST testbed

    NASA Astrophysics Data System (ADS)

    Hyde, Tupper; Kim, Ed; Anderson, Eric; Blackwood, Gary; Lublin, Leonard

    1990-12-01

    The MIT Space Engineering Research Center (SERC) has developed a controlled structures technology (CST) testbed based on one design for a space-based optical interferometer. The role of the testbed is to provide a versatile platform for experimental investigation and discovery of CST approaches. In particular, it will serve as the focus for experimental verification of CSI methodologies and control strategies at SERC. The testbed program has an emphasis on experimental CST--incorporating a broad suite of actuators and sensors, active struts, system identification, passive damping, active mirror mounts, and precision component characterization. The SERC testbed represents a one-tenth scaled version of an optical interferometer concept based on an inherently rigid tetrahedral configuration with collecting apertures on one face. The testbed consists of six 3.5 meter long truss legs joined at four vertices and is suspended with attachment points at three vertices. Each aluminum leg has a 0.2 m by 0.2 m by 0.25 m triangular cross-section. The structure has a first flexible mode at 31 Hz and has over 50 global modes below 200 Hz. The stiff tetrahedral design differs from similar testbeds (such as the JPL Phase B) in that the structural topology is closed. The tetrahedral design minimizes structural deflections at the vertices (site of optical components for maximum baseline) resulting in reduced stroke requirements for isolation and pointing of optics. Typical total light path length stability goals are on the order of lambda/20, with a wavelength of light, lambda, of roughly 500 nanometers. It is expected that active structural control will be necessary to achieve this goal in the presence of disturbances.

  4. Echtzeit-Ultraschallsimulation auf Grafik-Prozessoren mit CUDA

    NASA Astrophysics Data System (ADS)

    Reichl, Tobias; Passenger, Josh; Acosta, Oscar; Salvado, Olivier

    Trotz der zunehmenden Verbreitung jüngerer bildgebender Verfahren bleibt medizinischer Ultraschall (US) weiterhin ein wichtiges Hilfsmittel bei chirurgischen Eingriffen und der klinischen Diagnose. Viele US-gestützte medizinische Prozeduren erfordern allerdings ausgiebiges Training, so dass es wünschenswert ist, eine realistische Simulation von US-Bildern zur Verfügung zu stellen. Im Gegensatz zu früheren Ansätzen simulieren wir solche Bilder auf der "Graphics Processing Unit“. Wir erweitern hierzu eine Methode, die von Wein et al. für die Abschätzung von US-Reflexionen aus Daten der Computertomographie (CT) vorgeschlagen wurde, zu einer leichter zu berechnenden Form. Zusätzlich schätzen wir die US-Absorption aus den CT-Daten ab. Mit Hilfe von NVIDIAs "Compute Unified Device Architecture“ (CUDA) simulieren wir Reflexion, Verschattung, Rauschen und radiale Unschärfe, ausgehend von unbearbeiteten CT-Daten in Echtzeit und ohne Vorausberechnung.

  5. Cyber-Physical Systems - Wissenschaftliche Herausforderungen Bei Der Entwicklung

    NASA Astrophysics Data System (ADS)

    Broy, Manfred

    Cyber-Physical Systems adressieren die enge Verbindung eingebetteter Systeme zur Überwachung und Steuerung physikalischer Vorgänge mittels Sensoren und Aktuatoren über Kommunikationseinrichtungen mit den globalen digitalen Netzen (dem Cyberspace"). Dieser Typus von Systemen ermöglicht über Wirkketten eine Verbindung zwischen Vorgängen der physischen Realität und den heute verfügbaren digitalen Netzinfrastrukturen. Dies erlaubt vielfältige Applikationen mit hohem wirtschaftlichen Potential, und mit starker Innovationskraft. Die vollständige Ausschöpfung des Potentials erfordert aber gezielte wissenschaftliche Anstrengungen bei der Entwicklung solcher Systeme im Hinblick auf Methodik, Technologie, Kostenbeherrschung und funktionale Angemessenheit.

  6. MIT Space Engineering Research Center

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Miller, David W.

    1990-01-01

    The Space Engineering Research Center (SERC) at MIT, started in Jul. 1988, has completed two years of research. The Center is approaching the operational phase of its first testbed, is midway through the construction of a second testbed, and is in the design phase of a third. We presently have seven participating faculty, four participating staff members, ten graduate students, and numerous undergraduates. This report reviews the testbed programs, individual graduate research, other SERC activities not funded by the Center, interaction with non-MIT organizations, and SERC milestones. Published papers made possible by SERC funding are included at the end of the report.

  7. Einstellung und Wissen von Lehramtsstudierenden zur Evolution - ein Vergleich zwischen Deutschland und der Türkei

    NASA Astrophysics Data System (ADS)

    Graf, Dittmar; Soran, Haluk

    Es wird eine Untersuchung vorgestellt, in der Wissen und Überzeugungen von Lehramtsstudierenden aller Fächer zum Thema Evolution an zwei Universitäten in Deutschland und der Türkei erhoben worden sind. Die Befragung wurde in Dortmund und in Ankara durchgeführt. Es stellte sich heraus, dass ausgeprägte Defizite im Verständnis der Evolutionsmechanismen herrschen. Viele Studierende, insbesondere aus der Türkei, sind nicht von der Faktizität der Evolution überzeugt. Dies gilt sowohl für Studierende mit Fach Biologie als auch für Studierende mit anderen Fächern. Näher untersucht worden sind die Faktoren, die die Überzeugungen zur Evolution beeinflussen können, was ja in Anbetracht der hohen Ablehnungsrate der Evolution von besonderem Interesse ist. Das Vertrauen in die Wissenschaft spielt hierbei eine besondere Rolle: Wer der Wissenschaft vertraut, ist auch eher von der Evolution überzeugt, als diejenigen, die skeptisch gegenüber der Wissenschaft sind.

  8. MIT January Operational Internship Experience

    NASA Technical Reports Server (NTRS)

    Bosanac, Natasha; DeVivero, Charlie; James, Jillian; Perez-Martinez, Carla; Pino, Wendy; Wang, Andrew; Willett, Ezekiel; Williams, Kwami

    2010-01-01

    This viewgraph presentation describes the MIT January Operational Internship Experience (JOIE) program. The topics include: 1) Landing and Recovery; 2) Transportation; 3) Shuttle Processing; 4) Constellation Processing; 5) External Tank; 6) Launch Pad; 7) Ground Operations; 8) Hypergolic Propellants; 9) Environmental; 10) Logistics; 11) Six Sigma; 12) Systems Engineering; and 13) Human Factors.

  9. Identifikationsverfahren zur Analyse von EEG-Signalen bei Epilepsie mit Reaktions-Diffusions Netzwerken

    NASA Astrophysics Data System (ADS)

    Gollas, F.; Tetzlaff, R.

    2007-06-01

    Partielle Differentialgleichungen des Reaktions-Diffusions-Typs beschreiben Phänomene wie Musterbildung, nichtlineare Wellenausbreitung und deterministisches Chaos und werden oft zur Untersuchung komplexer Vorgänge auf den Gebieten der Biologie, Chemie und Physik herangezogen. Zellulare Nichtlineare Netzwerke (CNN) sind eine räumliche Anordnung vergleichsweise einfacher dynamischer Systeme, die eine lokale Kopplung untereinander aufweisen. Durch eine Diskretisierung der Ortsvariablen können Reaktions-Diffusions-Gleichungen häufig auf CNN mit nichtlinearen Gewichtsfunktionen abgebildet werden. Die resultierenden Reaktions-Diffusions-CNN (RD-CNN) weisen dann in ihrer Dynamik näherungsweise gleiches Verhalten wie die zugrunde gelegten Reaktions-Diffusions-Systeme auf. Werden RD-CNN zur Identifikation neuronaler Strukturen anhand von EEG-Signalen herangezogen, so besteht die Möglichkeit festzustellen, ob das gefundene Netzwerk lokale Aktivität aufweist. Die von Chua eingeführte Theorie der lokalen Aktivität Chua (1998); Dogaru und Chua (1998) liefert eine notwendige Bedingung für das Auftreten von emergentem Verhalten in zellularen Netzwerken. Änderungen in den Parametern bestimmter RD-CNN könnten auf bevorstehende epileptische Anfälle hinweisen. In diesem Beitrag steht die Identifikation neuronaler Strukturen anhand von EEG-Signalen durch Reaktions-Diffusions-Netzwerke im Vordergrund der dargestellten Untersuchungen. In der Ergebnisdiskussion wird insbesondere auch die Frage nach einer geeigneten Netzwerkstruktur mit minimaler Komplexität behandelt.

  10. Von Donuts und Zucker: Mit Neutronen biologische Makromoleküle erforschen

    NASA Astrophysics Data System (ADS)

    May, Roland P.

    2003-05-01

    Für die Erforschung von Biomolekülen bieten Neutronen einzigartige Eigenschaften. Vor allem ihre unterschiedliche Wechselwirkung mit dem natürlichen Wasserstoff und seinem schweren Isotop Deuterium ermöglicht tiefe Einblicke in Struktur, Funktion und Dynamik von Proteinen, Nukleinsäuren und Biomembranen. Bei vielen Fragestellungen zur Strukturaufklärung gibt es kaum oder keine Alternative zum Neutron. Das Institut Laue-Langevin trägt Bahnbrechendes zum Erfolg der Neutronen-Methoden in der Biologie bei.

  11. Sitzungsberichte der Heidelberger Akademie der Wissenschaften> " Jahrgang 1990 Sitzungsber.Heidelberg 90 " "Gott hat die Natur einfältig gemacht, sie aber suchen viel Künste"

    NASA Astrophysics Data System (ADS)

    Zehe, Horst

    Der Aufsatz demonstriert anhand ausgiebig kommentierter zeitgenössischer Zeugnisse Goethes Reaktion auf die Arbeiten Fraunhofers, insbesondere auf die Entdeckung der dunklen Linien im Sonnenspektrum. Den Fehlurteilen Goethes werden dabei die Urteile zeitgenössischer Physiker wie Chladni und J.F.W. Herschel gegenübergestellt. Bislang noch ungedruckte Dokumente aus dem Weimarer Goethe- und Schiller-Archiv belegen, daß sich Goethe nicht nur literarisch mit Fraunhofer beschäftigte, sondern daß er auch dessen Versuche mit Hilfe des Jenaer Universitätsmechanikers Körner getreulich zu wiederholen suchte.

  12. Phänomenologische Grundlagen der Wärmelehre

    NASA Astrophysics Data System (ADS)

    Heintze, Joachim

    Die Physik der Wärme lässt sich auf zweierlei Weise formulieren: Einmal als Mechanik eines Systems, das eine enorm große Zahl von Teilchen enthält (statistische Mechanik), und einmal mit Hilfe von ad hoc eingeführten Größen, den sogenannten Zustandsgrößen, die geeignet sind, das Verhalten eines solchen Systems zu beschreiben, ohne dass man die Teilchen selbst und ihre Bewegungen betrachten muss (Thermodynamik). Wir werden beide Ansätze in ihrer einfachsten und anschaulichsten Ausprägung in Kap. 5 (kinetische Gastheorie) bzw. in Kap. 8 (Grundbegriffe der Thermodynamik) behandeln. Obgleich sich die volle Durchführung des Programms als begrifflich und mathematisch recht schwierig erweist - die Vorlesung "Thermodynamik und Statistik" steht gewöhnlich am Ende der Kursvorlesungen über theoretische Physik - werden wir doch auf der Grundlage der Kap. 5 und 8 eine Menge über die Physik der Wärme lernen können. Den Ausgangspunkt der Wärmelehre bilden jedoch allemal die Naturerscheinungen, die wir hier in Kap. 4 behandeln wollen: Wärme, Kälte, Temperaturausgleich. Wir werden untersuchen, wie man diese Begriffe quantifizieren kann, und was bei der Erwärmung oder Abkühlung eines Körpers vor sich geht. Dabei werden wir auf den I. und II. Hauptsatz der Wärmelehre stoßen.

  13. Ökophysik: Plaudereien über das Leben auf dem Land, im Wasser und in der Luft

    NASA Astrophysics Data System (ADS)

    Nachtigall, W.

    Prof. em. Dr. rer. nat. Werner Nachtigall, geb. 1934, war als Zoophysiologe und Biophysiker Leiter des Zoologischen Instituts der Universität des Saarlandes in Saarbrücken. In Forschung und Ausbildung hat er sich insbesondere mit Aspekten der Technischen Biologie und Bionik befasst und mit seinen Forschergruppen viele Basisdaten insbesondere zur Ökologie, Physiologie und Physik des Fliegens und Schwimmens aber auch zur Stabilität beispielsweise der Gräser erarbeitet. Lebewesen überraschen immer wieder durch ihre "Biodiversität", ihre hochspezifischen Ausgestaltungen und Anpassungen.

  14. Unterstützung der IT-Service-Management-Prozesse an der Technischen Universität München durch eine Configuration-Management-Database

    NASA Astrophysics Data System (ADS)

    Knittl, Silvia

    Hochschulprozesse in Lehre und Verwaltung erfordern durch die steigende Integration und IT-Unterstützung ein sogenanntes Business Alignment der IT und damit auch ein professionelleres IT-Service-Management (ITSM). Die IT Infrastructure Library (ITIL) mit ihrer Beschreibung von in der Praxis bewährten Prozessen hat sich zum de-facto Standard im ITSM etabliert. Ein solcher Prozess ist das Konfigurationsmanagement. Es bildet die IT-Infrastruktur als Konfigurationselemente und deren Beziehungen in einem Werkzeug, genannt Configuration Management Database (CMDB), ab und unterstützt so das ITSM. Dieser Bericht beschreibt die Erfahrungen mit der prototypischen Einführung einer CMDB an der Technischen Universität München.

  15. Newtons Wissenschaftslehre als Basis der Quantenphysik

    NASA Astrophysics Data System (ADS)

    Bopp, Fritz

    Es ist richtig zu sagen, die Quantenphysik folge nicht aus der auf Newtons Prinzipien beruhenden klassischen Physik. Es ist aber auch richtig, daß Newtons Wissenschaftslehre, die eng mit der Platonschen zusammenhängt und über diese hinausgeht, von der Quantenphysik nicht berührt wird, wie an anderer Stelle gezeigt ist. Hier wird Newtons Wissenschaftslehre genauer analysiert und der Unterschied zur kartesischen herausgearbeitet, was durch die Newtontradition verschleiert wird. Am Ende werden die Ergebnisse an Beispielen aus der Quantenoptik erläutert.Translated AbstractNewton's Epistemology as Basic Concept of Quantum PhysicsIt is correct to say that quantum physics cannot be derived from classical physics, which is founded on Newton's principles. However, it is also correct that Newton's epistemology, a more developed Platonian one, can be considered as basic for quantum physics. That is previously shown. Here, we remember Newton's epistemology more thoroughly, and consider particularly the difference to the Cartesian epistemology, a difference often veiled in the Newton tradition. Finally, we apply the result on some phenomena of quantum optics.

  16. Erfahrungen im Aufbau des IT Service Desks der Technischen Universität München

    NASA Astrophysics Data System (ADS)

    Vellguth, Karmela

    Durch das Projekt IntegraTUM und die darin eingebettete Einrichtung eines IT Service Desks mit 1st, 2nd und 3rd Level Support gelang eine an ITIL orientierte Neuausrichtung der internen IT-Dienstleistungen. Die vormals existierende Struktur mit einer Vielzahl an Ansprechpartnern bei auftretenden IT-Problemen wurde aufgelöst. Die Nutzer haben nun eine Anlaufstelle erhalten, die sich für die Beantwortung aller Incidents in kürzester Zeit und mit qualitativ hohem Niveau zuständig fühlt.

  17. Die Struktur von schlankem Materialfluss mit Lean Production Kanban und Innovationen

    NASA Astrophysics Data System (ADS)

    Scheid, Wolf-Michael

    In der Literatur wird Materialfluss überwiegend in Spezialdisziplinen betrachtet, etwa der Steuerungslogik, der Logistiktechnik oder dem Supply Chain Management. Ein charakterisierendes Merkmal des Materialflusses ist jedoch, dass er sich aus vielfältigen Einzelbausteinen zusammensetzt, die alle harmonisch abgestimmt sein müssen. Die maximal erreichbare Effizienz wird nicht durch Höchstleistungen in dem einen oder anderen Spezialthema bestimmt, sondern durch das schwächste Glied im gesamten komplexen Netzwerk. Den Schnittstellen zwischen den betroffenen Fachbereichen in einem Unternehmen kommt hier eine ganz besondere Bedeutung zu: Erst ein harmonischer Einklang ermöglicht hohe Effektivität. Dies setzt umfassendes Verständnis für interdisziplinäre Notwendigkeiten, ein hohes Maß an Abstimmung mit den operativen Prozessen und letztlich einen einvernehmlichen Umgang und den Respekt vor den Problemstellungen des Anderen voraus.

  18. Quantifizierung neurodegenerativer Veränderungen bei der Alzheimer Krankheit

    NASA Astrophysics Data System (ADS)

    Fritzsche, Klaus H.; Giesel, Frederik L.; Thomann, Philipp A.; Hahn, Horst K.; Essig, Marco; Meinzer, Hans-Peter

    Die objektive Bewertung neurodegenerativer Prozesse stellt für die Diagnose und Therapiebegutachtung neuropsychiatrischer Krankheiten eine wichtige Grundlage dar. Computerbasierte radiodiagnostische Verfahren können pathologische Veränderungen in verschiedenen Hirnarealen quantifizieren und hierbei die rein visuelle Beurteilung der Bilddaten ergänzen. Inhalt dieser Studie ist die Evaluation einer voll automatischen Methode zur voxelbasierten Messung atrophischer Veränderungen im Gehirn, wie sie bei der Alzheimer-Demenz (AD) oder der leichten kognitiven Störung (LKS) auftreten. Es wurde eine signifikante Korrelation mit den semiautomatisch extrahierten Volumina der Temporalhörner festgestellt. Die Präzision, Benutzerfreundlichkeit, Beobachterunabh ängigkeit sowie die kurze Rechenzeit des automatischen Verfahrens sind wichtige Voraussetzungen für den routinemäßigen klinischen Einsatz.

  19. Der Weltraum. Die Originalfotografien der NASA.

    NASA Astrophysics Data System (ADS)

    Klotz, H.

    This book is based on an exhibition in 1985 of many of the spectacular images obtainedby NASA's planetary missions and Earth reconnaissance satellites during the past two decades. The exhibition was organized by the Baxter Art Gallery, California Institute of Technology, Pasadena. The photographs have been prepared by the Jet Propulsion Laboratory, Pasadena.Contents: Das Sonnensystem - eine geowissenschaftliche Betrachtung (W. Ziegler). Der beharrliche Beobachter (C. Knight).Der Weltraum. Ranger - Der Mond. Surveyor - Der Mond. Lunar-Orbiter -Der Mond. Mariner 4, 6, 7 - Mars. Mariner 10 - Venus, Merkur. Viking - Mars. Voyager - Jupiter. Voyager - Saturn. Voyager - Uranus. Voyager - Neptun. Seasat. IRAS. SIR-A und SIR-B. Galileo. Beta Pictoris. Laufende Weltraumprojekte. Zukünftige Weltraumprojekte. Ein Blick zurück... und nach vorn (M. Maegraith). Anhang - Die Probleme der Bildübertragung. Chronologie der Weltraumflüge.

  20. Kosmische Katastrophen und der Ursprung der Religion.

    NASA Astrophysics Data System (ADS)

    Hoyle, F.

    This book is a German translation, by V. Delavre, from the English original "The origin of the Universe and the origin of religion", published in 1993. Contents: E. Sens: Die unterbrochene Musikstunde. Einleitung zur deutschen Ausgabe. C. Ryskamp: Einführung. R. N. Anshen: Vorwort. F. Hoyle: Kosmische Katastrophen und der Ursprung der Religion - Die Folgen der Respektabilität; Eiszeiten und Kometen; Die allgemeine Situation in den Nacheiszeiten; Kometen und der Ursprung der Religionen; Der Übergang zu Mittelalter und Neuzeit. Diskussionsbeiträge: Ruth Nanda Anshen, Freeman Dyson, Paul Oscar Kristeller, John Archibald Wheeler, James Schwartz, Roger Shinn, Milton Gatch, Philip Solomon, Norman Newell. F. Hoyle: Schlußwort. A. Tollmann: Nachwort zur deutschen Ausgabe.

  1. Methodik der Erfassung und Bewertung von Biodiversitätsschäden aus ökologischer Sicht

    NASA Astrophysics Data System (ADS)

    Wiegleb, Gerhard; Krawczynski, René; Wagner, Hans-Georg

    Mit der Verabschiedung des Umweltschadensgesetzes (USchadG) hat der Schutz der Biodiversität in Deutschland ein neues Stadium erreicht. Zum ersten Male wird selbst die Vermeidung und Restitution der nichtintendierten Schädigung der Biodiversität in Gestalt bestimmter Arten und Lebensräume in ein umfassendes Naturschutzkonzept einbezogen. Das USchadG geht damit über die bisherigen Ansätze zum Schutz der belebten Natur hinaus, da es gleichzeitig neben der Erhaltung eines als günstig erkannten Ist-Zustandes der Biodiversität der Vermeidung vorhersehbarer Schäden sowie auch der Restitution nach einem eingetretenen Schaden verpflichtet ist. Naturschutzsystematisch gehört es wegen der Betonung der Vermeidung und Sanierung zum Bereich des reaktiven Naturschutzes (Gefahrenabwehr und Gefahrenbeseitigung), dem auch die Eingriffsregelung des Bundesnaturschutzgesetzes (BNatSchG), die Umweltverträglichkeitsprüfung nach Umweltverträglichkeitsprüfungsgesetz (UVPG) sowie die FFH-Verträglichkeitsprüfung nach Fauna-Flora-Habitat-Richtlinie (FFH-RL) zuzurechnen sind. Stärker noch als in den genannten Regelungen tritt im USchadG das Verursacherprinzip gegenüber der allgemeinen Umweltvorsorge in den Vordergrund.

  2. Sitzungsberichte der Heidelberger Akademie der Wissenschaften¬Jahrgang 1990 Sitzungsber.Heidelberg 90¬"Gott hat die Natur einfältig gemacht, sie aber suchen viel Künste"

    NASA Astrophysics Data System (ADS)

    Zehe, Horst

    Der Aufsatz demonstriert anhand ausgiebig kommentierter zeitgenössischer Zeugnisse Goethes Reaktion auf die Arbeiten Fraunhofers, insbesondere auf die Entdeckung der dunklen Linien im Sonnenspektrum. Den Fehlurteilen Goethes werden dabei die Urteile zeitgenössischer Physiker wie Chladni und J.F.W. Herschel gegenübergestellt. Bislang noch ungedruckte Dokumente aus dem Weimarer Goethe- und Schiller-Archiv belegen, daß sich Goethe nicht nur literarisch mit Fraunhofer beschäftigte, sondern daß er auch dessen Versuche mit Hilfe des Jenaer Universitätsmechanikers Körner getreulich zu wiederholen suchte.

  3. Grundlagen der Mechatronik

    NASA Astrophysics Data System (ADS)

    Roddeck, Werner

    Der Begriff Mechatronik ist ein Kunstwort, welches durch Eindeutschung des englischen Wortes "Mechatronics“ entstanden ist. Dieses ist wiederum eine Zusammenziehung der englischen Bezeichnungen für "Mechanics“ (Maschinenbau) und "Electronics“ (Elektrotechnik). Der Begriff wurde durch einen japanischen Ingenieur 1969 geprägt und durch eine japanische Firma bis 1972 als Warenzeichen gehalten.

  4. Workstation-assisted education at MIT

    NASA Astrophysics Data System (ADS)

    Champine, George A.

    1992-06-01

    MIT launched a major new initiative called Project Athena in 1983 to improve the quality of education through the introduction of a high-quality computing infrastructure throughout the campus. Implementation of the Project Athena computing environment required eight years, cost about 100 million, and was sponsored by Digital Equipment and IBM in addition to MIT. The Athena computing environment is based almost entirely on workstations from these two vendors using the Unix operating system. Project Athena is now complete. The resulting computer system has been turned over to the campus computing organization for ongoing operation and maintenance. The computing environment available at MIT for education has been significantly improved. Students are graduating today that have never known life at MIT without the ubiquitous availability of high-quality computing. This article provides an overview of the initial objectives and strategies of Project Athena at MIT relative to its educational use. The specific strategies that MIT employed in the use of work-stations in educational are then described. These strategies are contrasted with other available strategies. Specific examples of the use of workstations are presented. An important element in current and future education delivery is multimedia. Athena in conjunction with the MIT Media Lab has one of the largest efforts in multimedia development of any of the universities, and MIT is using multimedia in education on a daily basis. A new laboratory, the Center for Educational Computing Initiatives, has been established with a major focus on multimedia. Finally the lessons learned from Athena relative to its primary objective — that of improving education — are reviewed.

  5. Demographische Entwicklung in der Metropolregion Berlin-Brandenburg

    NASA Astrophysics Data System (ADS)

    Beyer, Wolf; Bluth, Friedrich

    〝Denn eins ist sicher: Die Rente.`` Der vielzitierte Satz des früheren Arbeits- und Sozialministers Norbert Blüm klingt heute vielen wie Hohn. Der Altersaufbau der deutschen Bevölkerung erinnert grafisch immer mehr an einen Baum auf dünnem Stämmchen als an eine Pyramide. Angesichts dessen rücken demographische Entwicklungen mehr und mehr in den Fokus der Öffentlichkeit. Besonders die neuen Bundesländer sind massiv von Abwanderung und einem nie dagewesenen Geburtenrückgang betroffen.DIPL.-GEOGR. UTE C. BAUERsprach mitFRIEDRICH BLUTHundWOLF BEYERüber die Besonderheiten der demographischen Prozesse in Berlin und Brandenburg. Beyer leitete bis Anfang 2004 das brandenburgische Referat für Raumbeobachtung. Seine Aufgabe bestand darin, Planungsgrundlagen für die Gemeinsame Landesplanung Berlin-Brandenburg(GL) zu schaffen. Dazu zählen auch Bevölkerungsprognosen für die Kreise und Städte Brandenburgs. Bluth ist in der Senatsverwaltung für Stadtentwicklung Berlin beschäftigt und leitet dort die Gruppe 〝Stadtwissen, Stadtentwicklungsmonitoring, Bevölkerungsprognose.``

  6. Intraoperative Schnellschnittuntersuchungen parapylorischer Lymphknoten bei der pyloruserhaltenden Pankreaskopfresektion: Gibt es eine klinische Relevanz?

    PubMed Central

    Riediger, Hartwig; Schulz, Antje; Adam, Ulrich; Krüger, Colin M.

    2014-01-01

    Zusammenfassung Hintergrund Die pyloruserhaltende Pankreaskopfresektion (PPPD) ist als onkologisches Standardverfahren etabliert. Lokal fortgeschrittene Tumoren können eine erweiterte Resektion erforderlich machen. Ebenso soll früheren Arbeiten zufolge bei Tumornachweis in den parapylorischen Lymphknoten (PLK) eine distale Magenresektion im Sinne einer klassischen Whipple-Operation indiziert sein. Entsprechend diesen Empfehlungen haben wir intraoperative Schnellschnittuntersuchungen der PLK in unseren Routineablauf integriert. Im Rahmen dieser Studie haben wir die klinische Relevanz dieses Vorgehens hinterfragt. Methoden Bei 105 onkologischen Patienten im Zeitraum von 2006-2012 bestand die Indikation zur PPPD. In allen Fällen erfolgte eine intraoperative Schnellschnittuntersuchung der PLK. Die Patienten wurden bezüglich Primärtumor, Anzahl der untersuchten Lymphknoten (LK) (gesamt und parapylorisch) sowie Auswirkungen auf das operative Konzept untersucht. Es handelt sich um eine retrospektive Studie, die auf prospektiv erhobenen Daten unserer Pankreasdatenbank basiert. Ergebnisse Die Primärtumoren waren 72 Pankreaskopfkarzinome und 33 extrapankreatische Karzinome (Gallengangskarzinom, Ampullenkarzinom, Duodenalkarzinom). 73 Patienten waren nodalpositiv. Insgesamt wurden 2391 LK untersucht, von denen 325 parapylorisch lokalisiert waren. Die intraoperative Schnellschnittuntersuchung erbrachte lediglich bei 4 Patienten mit Pankreaskopfkarzinom jeweils einen positiven PLK; daraufhin erfolgte eine distale Magenresektion. In keinem der distalen Magenresektate waren Tumorresiduen nachweisbar. Lokale chirurgisch-technische Probleme im Sinne von Durchblutungsstörungen des Magens ergaben sich durch die regionale Lymphadenektomie nicht. PLK waren nur beim Pankreaskarzinom positiv. In der Subgruppe der nodalpositiven Patienten mit Pankreaskopfkarzinom hatten 8% der Patienten einen positiven PLK. Schlussfolgerung Die regionale parapylorische Lymphadenektomie ist beim

  7. Ludwig Boltzmann als Experimentalphysiker: Frühe Bestätigung der Maxwell-Theorie

    NASA Astrophysics Data System (ADS)

    Rumpf, Klemens; Granitzer, Petra

    2006-09-01

    Am Beispiel von Boltzmanns Experimenten zur Bestätigung der Maxwell-Theorie wird dessen hervorragende Begabung auch als Experimentalphysiker deutlich. Die dargestellten Arbeiten fanden etwa 15 Jahre vor den Hertzschen Experimenten statt, zu einem Zeitpunkt also, als die noch junge Maxwell-Theorie dringend experimenteller Bestätigung bedurfte. Boltzmann konnte mit seinen experimentellen Untersuchungen eine direkte Konsequenz der Maxwellschen elektromagnetischen Theorie, die so genannte Maxwell-Relation, bestätigen. Seine Experimente stellten nicht nur lange Zeit den stärksten Beleg für die Richtigkeit der Maxwellschen Lichttheorie dar, sondern waren eine experimentelle Spitzenleistung an der Grenze des damals Möglichen. Besonders Boltzmanns Bestimmung der Dielektrizitätskonstanten von Gasen fand noch Jahrzehnte später Erwähnung in namhaften Lehrbüchern.

  8. Wie wissenschaftlich ist der Evolutionsgedanke?

    NASA Astrophysics Data System (ADS)

    Vollmer, Gerhard

    Darwin war ein besonnener Mann; alles Aufsehen war ihm zuwider. Trotzdem hat er eine Revolution ausgelöst, deren Wirkung nicht auf die Biologie beschränkt blieb. Seine Theorie lässt sich in fünf Teiltheorien zerlegen, die sich durch die Begriffe Artenwandel, Verwandtschaft alles Lebendigen und gemeinsamer Ursprung, Artenaufspaltung und Artenvielfalt, Gradualismus, natürliche Auslese charakterisieren lassen. Dadurch wurden mehrere religiöse und weitere weltanschauliche Überzeugungen in Frage gestellt. Deshalb wird die Evolutionstheorie auch heute noch vielfach kritisiert, ja bekämpft. Die Vorwürfe lassen sich ordnen nach den Kriterien, mit denen wir erfahrungswissenschaftliche Theorien beurteilen. Haltbar ist daran nur, dass es für die Evolutionstheorie zwar beliebig viele Bestätigungen gibt, aber nur wenige Widerlegungsmöglichkeiten. Durch die neuerdings entwickelten und durchgeführten Evolutionsexperimente ist die empirische Situation allerdings deutlich besser geworden. Am (erfahrungs)wissenschaftlichen Charakter der Evolutionstheorie besteht deshalb kein Zweifel.

  9. Kants Theorie der Sonne: Physikgeschichte

    NASA Astrophysics Data System (ADS)

    Jacobi, Manfred

    2005-01-01

    Im Rahmen seiner Kosmogonie entwickelte der junge Immanuel Kant eine Theorie der Sonne. Sie ist ein einzigartiges Zeugnis seiner intuitiven Vorstellungskraft und beweist auch die Leistungsfähigkeit der damaligen, vorwiegend von Newton geprägten Weltsicht. Entstehung, Aufbau und Dynamik der Sonne werden in Kants Theorie ebenso erklärt wie etwa das Phänomen der Sonnenflecken.

  10. Zu einer inhaltsorientierten Theorie des Lernens und Lehrens der biologischen Evolution

    NASA Astrophysics Data System (ADS)

    Wallin, Anita

    Der Zweck dieser Studie (zwecks Überblick siehe dazu Abb. 9.1) war zu untersuchen, wie die Schüler der Sekundarstufe II ein Verständnis von der Theorie der biologischen Evolution entwickeln. Vom Ausgangspunkt "Vorurteile der Schüler“ ausgehend wurden Unterrichtssequenzen entwickelt und drei verschiedene Lernexperimente in einem zyklischen Prozess durchgeführt. Das Wissen der Schüler wurde vor, während und nach den Unterrichtssequenzen mit Hilfe von schriftlichen Tests, Interviews und Diskussionsrunden in kleinen Gruppen abgefragt. Etwa 80 % der Schüler hatten vor dem Unterricht alternative Vorstellungen von Evolution, und in dem Nachfolgetest erreichten circa 75 % ein wissenschaftliches Niveau. Die Argumentation der Schüler in den verschiedenen Tests wurde sorgfältig unter Rücksichtnahme auf Vorurteile, der konzeptionellen Struktur der Theorie der Evolution und den Zielen des Unterrichts analysiert. Daraus konnten Einsichten in solche Anforderungen an Lehren und Lernen gewonnen werden, die Herausforderungen an Schüler und Lehrer darstellen, wenn sie anfangen, evolutionäre Biologie zu lernen oder zu lehren. Ein wichtiges Ergebnis war, dass das Verständnis existierender Variation in einer Population der Schlüssel zum Verständnis von natürlicher Selektion ist. Die Ergebnisse sind in einer inhaltsorientierten Theorie zusammengefasst, welche aus drei verschiedenen Aspekten besteht: 1) den inhaltsspezifischen Aspekten, die einzigartig für jedes wissenschaftliche Feld sind; 2) den Aspekten, die die Natur der Wissenschaft betreffen; und 3) den allgemeinen Aspekten. Diese Theorie kann in neuen Experimenten getestet und weiter entwickelt werden.

  11. [Vegetarische und vegane Ernährung bei Kindern - Stand der Forschung und Forschungsbedarf].

    PubMed

    Keller, Markus; Müller, Stine

    2016-01-01

    Die Praxis vegetarischer Ernährungsformen ist in Deutschland im letzten Jahrzehnt deutlich angestiegen. Allerdings ist der Anteil vegetarischer und veganer Kinder dabei unbekannt. Studien mit Erwachsenen zeigen das präventive Potenzial, aber auch potenzielle Schwachstellen pflanzenbasierter Kostformen. Die Vorteile und Risiken einer vegetarischen bzw. veganen Ernährung im Kindesalter wurden bisher jedoch relativ selten untersucht. Außerdem lassen das unterschiedliche Alter der Kinder, das heterogene Studiendesign sowie die teilweise geringe Probandenzahl der Studien keine verbindlichen Aussagen zu. In dieser Übersichtsarbeit werden die Ergebnisse der wenigen Studien zu vegetarisch und vegan ernährten Kindern (< 12 Jahren) in Nordamerika und Europa zusammengefasst. Demnach lag die Zufuhr von Nahrungsenergie und Makronährstoffen vegetarischer und veganer Kinder meist näher an den Empfehlungen der Fachgesellschaften als die Ernährung gleichaltriger Mischkostkinder. Ebenso wiesen vegetarisch und vegan ernährte Kinder eine höhere Zufuhr von und bessere Versorgung mit verschiedenen Vitaminen und Mineralstoffen auf. Häufiger zeigten sich jedoch Defizite bei Vitamin B12, Zink, Kalzium, Eisen und Vitamin D. Das Wachstum und die Entwicklung vegetarisch und vegan ernährter Kinder entsprachen weitgehend den Referenzstandards, wobei sie dazu tendierten, leichter, schlanker und (< 5 Jahren) auch kleiner zu sein. Aufgrund der unzureichenden Studienlage besteht erheblicher Forschungsbedarf zu den Auswirkungen einer vegetarischen und veganen Ernährung im Kindesalter.

  12. [Vegetarische und vegane Ernährung bei Kindern - Stand der Forschung und Forschungsbedarf].

    PubMed

    Keller, Markus; Müller, Stine

    2016-01-01

    Die Praxis vegetarischer Ernährungsformen ist in Deutschland im letzten Jahrzehnt deutlich angestiegen. Allerdings ist der Anteil vegetarischer und veganer Kinder dabei unbekannt. Studien mit Erwachsenen zeigen das präventive Potenzial, aber auch potenzielle Schwachstellen pflanzenbasierter Kostformen. Die Vorteile und Risiken einer vegetarischen bzw. veganen Ernährung im Kindesalter wurden bisher jedoch relativ selten untersucht. Außerdem lassen das unterschiedliche Alter der Kinder, das heterogene Studiendesign sowie die teilweise geringe Probandenzahl der Studien keine verbindlichen Aussagen zu. In dieser Übersichtsarbeit werden die Ergebnisse der wenigen Studien zu vegetarisch und vegan ernährten Kindern (< 12 Jahren) in Nordamerika und Europa zusammengefasst. Demnach lag die Zufuhr von Nahrungsenergie und Makronährstoffen vegetarischer und veganer Kinder meist näher an den Empfehlungen der Fachgesellschaften als die Ernährung gleichaltriger Mischkostkinder. Ebenso wiesen vegetarisch und vegan ernährte Kinder eine höhere Zufuhr von und bessere Versorgung mit verschiedenen Vitaminen und Mineralstoffen auf. Häufiger zeigten sich jedoch Defizite bei Vitamin B12, Zink, Kalzium, Eisen und Vitamin D. Das Wachstum und die Entwicklung vegetarisch und vegan ernährter Kinder entsprachen weitgehend den Referenzstandards, wobei sie dazu tendierten, leichter, schlanker und (< 5 Jahren) auch kleiner zu sein. Aufgrund der unzureichenden Studienlage besteht erheblicher Forschungsbedarf zu den Auswirkungen einer vegetarischen und veganen Ernährung im Kindesalter. PMID:27160086

  13. Testen komplexer digitaler Schaltungen mit Python

    NASA Astrophysics Data System (ADS)

    Reichör, S.; Hueber, G.; Hagelauer, R.; Lindorfer, M.

    2004-05-01

    Die Verifikation von digitalen Schaltungen nimmt heutzutage einen bedeutenden Stellenwert ein. In diesem Paper wird ein Weg beschrieben, der die Erstellung und Wartung von funktionalen Testbenches für digitale Designs unterstützt. Für viele Projekte übersteigt der zeitliche Aufwand für das Testen den Aufwand für die Implementierung der Schaltung. In vielen Fällen beträgt der Aufwand für das Testen bereits 70% des Entwicklungsaufwands (Bergeron, 2000). Typischerweise wird die Testbench auch in der gewählten Hardwarebeschreibungssprache (VHDL oder Verilog) implementiert. Diese Sprachen stellen jedoch nicht die beste Wahl für Verifikationsbelange dar. Gründe dafür sind darin zu suchen, dass diese Sprachen wichtige Konzepte aus den Softwaresprachen (wie z.B. Objektorientierung) nicht kennen. Weiters stehen komfortable Softwarebibliotheken (Zufallszahlengenerierung, Stringverarbeitung, etc.) den Hardwaresprachen nicht zur Verfügung. In diesem Paper wird der Einsatz der Programmiersprache Python (PythonHomepage, 2003; Beazley, 2001) für die Verifikation vorgeschlagen, um die benötigte Zeit für die Funktionalen Tests zu reduzieren.

  14. Die Kosmologie der Griechen.

    NASA Astrophysics Data System (ADS)

    Mittelstraß, J.

    Contents: 1. Mythische Eier. 2. Thales-Welten. 3. "Alles ist voller Götter". 4. Griechische Astronomie. 5. "Rettung der Phänomene". 6. Aristotelische Kosmololgie. 7. Aristoteles-Welt und Platon-Welt. 8. Noch einmal: die Göttlichkeit der Welt. 9. Griechischer Idealismus.

  15. Wrestling with Pedagogical Change: The TEAL Initiative at MIT

    ERIC Educational Resources Information Center

    Breslow, Lori

    2010-01-01

    In the late 1990s, the physics department at the Massachusetts Institute of Technology (MIT) had a problem. The department was responsible for teaching the two required physics courses that are part of the General Institute Requirements (GIRs), MIT's core curriculum--Physics I (mechanics, or in MIT parlance, 8.01) and Physics II (electricity and…

  16. Konstruieren von Pkw-Karosserien: Grundlagen, Elemente und Baugruppen, Vorschriftenübersicht, Beispiele mit CATIA V4 und V5

    NASA Astrophysics Data System (ADS)

    Grabner, Jörg; Nothhaft, Richard

    Die Faszination, die vom Auto ausgeht, ist und bleibt ungebrochen. Entsprechend interessant ist es, sich vor dem Hintergrund konventioneller Konstruktionstechniken über die virtuelle Produktentwicklung von Pkw-Karosserien an modernen CAD-Arbeitsplätzen informieren zu können. Die Autoren führen in die Grundlagen ein und zeigen anhand von Beispielen und zahlreichen Abbildungen, wie mit dem System CATIA der Rohbau sowie die Ausstattung innen und au=C3=9Fen konstruiert werden. Darüber hinaus wird das so genannte "Package" an Beispielen beschrieben, also das Management und die Harmonisierung der Anforderungen an die Bauräume (z.

  17. Melker Meilensteine auf dem Weg in ein naturwissenschaftliches Zeitalter - Glanzlichter der Ausstellung zum Internationalen Astronomiejahr 2009 in der Melker Stiftsbibliothek.

    NASA Astrophysics Data System (ADS)

    Beck, Paul G.; Zotti, Georg

    2009-06-01

    Das Mittelalter wird weithin als die dunkle Epoche in der Geschichte der Europäischen Wissenschaften betrachtet, und insbesondere das Leben in den Klöstern galt lange Zeit als frei von jeglichem Interesse für Naturwissenschaften abseits der Medizin. Im Mittelalter galt die Astronomie bloß als Mittel zum Zweck, um religiöse und zivile Kalender erstellen zu können. Durch den Bestand der Handschriftenkammer der Melker Stiftsbibliothek eröffnet sich uns eine neue Sichtweise auf das gegen Ende des Mittelalters wachsende Interesse an den Naturwissenschaften. Dies wurde durch die starke Aufwertung der Klosterbibliothek im Rahmen der 'Melker Reform' im 15. Jahrhundert noch weiter verstärkt. Diese Epoche fällt mit der Frühphase der Universität Wien und der 'ersten Wiener Schule der Astronomie' zusammen. Dieser Artikel beleuchtet ausgewählte astronomischen Werke in der Melker Stiftsbibliothek zwischen dem frühen 9 und dem 18. Jahrhundert. Einen Schwerpunkt stellt das Wirken der Wiener Schule der Astronomie dar, wobei wir u.a. die Melker Abschrift von Peuerbachs Gutachten über den Kometen von 1456 sowie die im Stift Melk durchgeführte Beobachtung der Mondfinsternis von 1457 durch Regiomontanus und Peuerbach beleuchten. Dieser Beitrag ist der einführende Übersichtsartikel zum Ausstellungsprojekt in der Melker Stiftsbibliothek im Rahmen des Internationalen Jahres der Astronomie 2009. The medieval period is commonly seen as a dark epoch for science in Europe. Especially monasteries were seen as institutions without interest in natural sciences except for medicine. Astronomy was allegedly only a tool to construct religious and civil calendars. The inventory of the medieval manuscript collection of the library of the Abbey of Melk allows a new view on the growing interest in the exact sciences towards the end of the medieval ages. This interest was intensified through the increased importance of the monastery library due to the monastery reform

  18. Regenerative Energieträger im Aufwind: Entwicklung der erneuerbaren Energien

    NASA Astrophysics Data System (ADS)

    Kohl, Harald

    2006-05-01

    2005 kam 4,6 % des deutschen Primär-Energieverbrauchs aus erneuerbaren Energiequellen, bei der Stromproduktion lag ihr Anteil bei 10,2 %. Wesentliche Ursache ist der Boom bei der Windkraft, die vor allem durch Offshore-Windparks auf See weiter ausbaubar ist. Die Wasserkraft lieferte in Deutschland traditionell einen großen Beitrag zur Stromerzeugung, doch ihr Ausbaupotenzial ist gering. Die Photovoltaik, die solar- und die geothermische Stromerzeugung spielen derzeit noch eine kleine Rolle. Den deutschen Bedarf an Wärmeenergie deckten 2004 die erneuerbaren Energien zu 5,4 %, vor allem aus Biomasse. Die solarthermische Wärmeerzeugung hat sich gegenüber 2000 mehr als verdoppelt. Im Straßenverkehr spielen biogene Kraftstoffe mit 5,4 % noch eine untergeordnete Rolle. Bis 2050 könnte in Deutschland der Anteil regenerativer Energien am Primär-Energieverbrauch die Fünfzigprozentmarke überschreiten.

  19. Flight research with the MIT Daedalus prototype

    NASA Technical Reports Server (NTRS)

    Bussolari, Steven R.; Youngren, Harold H.; Langford, John S.

    1987-01-01

    The MIT Light Eagle human-powered aircraft underwent long-duration testing over Rogers Dry Lake in California during January, 1987. Designed as a prototype for the MIT Daedalus Project, the Light Eagle's forty-eight flights provided pilot training, established new distance records for human-powered flight, and provided quantitative data through a series of instrumented flight experiments. The experiments focused on: (1) evaluating physiological loads on the pilot, (2) determining airframe power requirements, and (3) developing an electronic flight control system. This paper discusses the flight test program, its results and their implications for the follow-on Daedalus aircraft, and the potential uses of the Light Eagle as a low Reynolds number testbed.

  20. Mishap Investigation Team (MIT) - Barksdale AFB, Louisiana

    NASA Technical Reports Server (NTRS)

    Stepaniak, Philip

    2005-01-01

    The Shuttle Program is organized to support a Shuttle mishap using the resources of the MIT. The afternoon of Feb. 1, 2003, the MIT deployed to Barksdale AFB. This location became the investigative center and interim storage location for crewmembers received from the Lufkin Disaster Field Office (DFO). Working under the leadership of the MIT Lead, the medical team executed a short-term plan that included search, recovery, and identification including coordination with the Armed Forces Institute of Pathology Temporary operations was set up at Barksdale Air Force Base for two weeks. During this time, coordination with the DFO field recovery teams, AFIP personnel, and the crew surgeons was on going. In addition, the crewmember families and NASA management were updated daily. The medical team also dealt with public reports and questions concerning biological and chemical hazards, which were coordinated with SPACEHAB, Inc., Kennedy Space Center (KSC) Medical Operations and the Johnson Space Center (JSC) Space Medicine office. After operations at Barksdale were concluded the medical team transitioned back to Houston and a long-term search, recovery and identification plan was developed.

  1. Epigenetische Aspekte bei Karzinomen der Kopf-Hals-Region

    PubMed Central

    Schmezer, Peter; Plass, Christoph

    2009-01-01

    Zusammenfassung Plattenepithelkarzinome der Kopf-Hals-Region (HNSCC) zählen seit Jahren zu den weltweit häufigsten Krebsarten. Trotz vieler Bemühungen hat sich das 5-Jahres-Überleben bei Patienten mit HNSCC kaum verbessert. Um einen Fortschritt zu erzielen, ist es notwendig, die der Erkrankung zugrunde liegenden biologischen Prozesse besser zu verstehen. Neben den bekannten genetischen Veränderungen haben molekular-zytogenetische Untersuchungen bei HNSCC gezeigt, dass es weitere Veränderungen gibt, die mit Vermehrung und Verlust chromosomaler Bereiche einhergehen, für die jedoch die krankheitsverursachenden Gene bisher nicht identifiziert wurden. Darüberhinaus haben jüngste Forschungsergebnisse verdeutlicht, dass epigenetische Modifikationen wie die DNA Methylierung eine wichtige Rolle spielen. So konnte gezeigt werden, dass bei HNSCC eine Reihe von Genen (z.B. das Tumorsuppressorgen CDKN2A sowie DAPK1, MGMT, TIMP3, TCF21, und C/EBPα) hypermethylierte Bereiche in regulatorischen DNA Sequenzen aufweisen, wodurch ihre Expression verringert oder unterbunden wird. Die Hypermethylierung solcher Gene könnte als Biomarker zur Früherkennung von HNSCC genutzt werden und nicht zuletzt dadurch zur Verbesserung von Prävention und Therapieerfolg beitragen. PMID:18483718

  2. Star in Deep Freeze Chills Theory, MIT Researchers Report

    NASA Astrophysics Data System (ADS)

    2001-09-01

    also at MIT. "We may have identified a new type of neutron star system that can lie dormant for thousands of years. If so, there could be hundreds of these systems in our Galaxy." The next step is to use Chandra to take the temperature of scores of other neutron stars experiencing various phases of accretion and quiescence. Other members of the observation team include Jon Miller of MIT, Craig Markwardt from NASA Goddard Space Flight Center, and Michiel van der Klis from the University of Amsterdam. The observation was made with Chandra's Advanced CCD Imaging Spectrometer, which was conceived and developed for NASA by Pennsylvania State University and MIT.

  3. MIT Space Engineering Research Center testbed programs

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Miller, David W.

    1991-01-01

    The Space Engineering Research Center (SERC) at M.I.T., started in July 1988, has completed two and one-half years of research. This Semi-Annual Report presents annotated viewgraph material presented at the January 1991 Steering Committee and Technical Representative Review. The objective of the Space Engineering Research Center is to develop and disseminate a unified technology of controlled structures. There has been continued evolution of the concept of intelligent structures (including in this past year the first successful embedding of a microelectronic component into a structural element).

  4. The MIT Program, Competition, and Ethics

    NASA Astrophysics Data System (ADS)

    Bradt, Hale V.

    2013-01-01

    The MIT program in x-ray astronomy was, and still is, diverse and productive. Bruno Rossi and later George Clark, as the nominal leaders of the “x-ray astronomy group” created a “hands-off” culture wherein individual researchers could develop their own independent programs. Walter Lewin, Claude Canizares, and I as well as those in the next academic generations, e.g., Saul Rappaport and George Ricker, were able to thrive in this environment. MIT researchers were principal investigators or providers of x-ray instruments on sounding rockets and balloons in the 1960s and then in later years on nine satellite missions, OSO-7, SAS-3, HEAO-1, Einstein, ASCA, RXTE, Chandra, HETE-2, and Suzaku. Such a diverse program involved collaborations with other institutions and of course striving for primacy in discovery and competition for NASA resources. Looking back, I see a high degree of ethical behavior among the observational x-ray community during those years. In competition, we remembered that we might well be collaborating the following year and behaved accordingly. Many of us in the x-ray community had been friends since graduate school days and did not want to lose those relationships. Am I viewing the past through rose colored glasses? I think not. A vignette on this topic: In 1967, I was debating vigorously with Herb Gursky of AS&E about which institution, MIT or AS&E, should be the lead on the fourth paper (Oda et al. 1967, ApJ 148, L5) based on data from the 1966 AS&E rocket flight which had led to Allan Sandage’s (and Japanese) identification of Sco X-1 (Sandage, et al. 1966, ApJ. 146, 316). I and my Italian colleague, Gianfranco Spada, and our Japanese colleague, Minoru Oda, both then visiting MIT, had actively supported that flight. After one rather heated discussion with Herb about this, - I was the heated one; he always remained calm - he left my office saying: “Hale, however this comes out, let’s remain friends.” I treasured that comment and

  5. Kindern das Wort Geben ein interkulturell-kreativer Arbeitsansatz, aufgezeigt an der Arbeit mit tibetischen Migrantenkindern

    NASA Astrophysics Data System (ADS)

    Rabkin, Gabriele

    2001-03-01

    Promotion of creativity in the cause of peace and international understanding is a fundamental part of the UNESCO programme to build a culture of peace. A central aspect of this undertaking consists in encouraging children to express themselves freely on this subject in writing and art. An approach has been developed to stimulate children's creativity and to create a link between creative expression and education for intercultural understanding. This article is divided into two parts. The first explains the pedagogical and psychological concepts behind this approach. The second describes a project in which these concepts were applied. It focuses on a minority dispersed over many parts of the world, namely children of Tibetan families. The description is accompanied by commentaries of the Fourteenth Dalai Lama, arising from a personal audience granted to the author in 1999.

  6. Grundwassermonitoring im Zusammenhang mit der hydraulischen Stimulation einer Erdölbohrung

    NASA Astrophysics Data System (ADS)

    Bönsch, Carola; Basan, Swantje

    2016-06-01

    The petroleum well Barth-11 in Mecklenburg-Western Pommerania (2700 m deep) is the first well in eastern Germany to use horizontal directional drilling. Hydraulic stimulation was performed in June 2014, connecting the oil reservoir and borehole. Five Pleistocene aquifers lie within the investigation area, with aquifer depths ranging between 5 and 90 m below surface. Three observation wells were installed for groundwater monitoring. Two weeks before hydraulic stimulation, reference measurements were conducted and a data logger was installed for measurements of water level, temperature and electrical conductivity. To detect any possible influence of hydraulic stimulation on groundwater quality, groundwater samples were analysed for several organic and inorganic parameters. The investigation area is located in a natural saline water discharge zone. Hence, it was necessary to develop methods to distinguish hydraulic stimulation water from Triassic and Permian formation saline water in order to uniquely identify any trace of the injected fluid in the natural groundwater. These methods and the monitoring system design are presented and discussed.

  7. MMPI and MIT Discriminators of Biogenic and Psychogenic Impotence

    ERIC Educational Resources Information Center

    Beutler, Larry E.; And Others

    1975-01-01

    Male patients complaining of impotence (N=32) were administered the Male Impotence Test (MIT) and the Minnesota Multiphasic Personality Inventory (MMPI). The results suggested that the MIT is without value for differentiating between psychogenic and biogenic impotence, whereas two rules from the MMPI appropriately classified 90 percent of the…

  8. Der vollständige Brief Brahes an Sørensen über das Erscheinen des Kometen von 1577

    NASA Astrophysics Data System (ADS)

    Kirschner, Stefan

    Es ist erstaunlich, daß sowohl Friis als auch Dreyer in ihrer Ausgabe der Briefe Tycho Brahes den Brief vom 14. November 1577 an Peter Sørensen, die erste bekannte Nachricht Brahes von seiner Entdeckung des Kometen von 1577, nur unvollständig, und zwar ohne den astronomischen Inhalt, ediert haben. Der Brief, dessen Original sehr wahrscheinlich nicht mehr existiert, wurde von dem Kieler Arzt und Medizinprofessor Johann Daniel Major (1634 - 1693) in Kopenhagen in sein Reisetagebuch kopiert. Das Original des Majorschen Reisetagebuches ist verschollen, doch es existieren zwei Abschriften davon (Kopenhagen, Königl. Bibl., Ny Kgl. Sml., 365, Fol. u. Ledreborg, 410, Fol.). Im folgenden wird nach einer kurzen Beschreibung des Stellenwerts, den der Komet von 1577 für Brahe besaß, der Brief nach diesen beiden Abschriften kritisch ediert, mit einer deutschen Übersetzung versehen und kurz kommentiert.

  9. IntegraTUM Teilprojekt Verzeichnisdienst: Identity & Access Management als technisches Rückgrat der Hochschul-IuK-Infrastruktur

    NASA Astrophysics Data System (ADS)

    Boursas, Latifa; Ebner, Ralf; Hommel, Wolfgang; Knittl, Silvia; Pluta, Daniel

    Als zentrales technisches Teilprojekt konzipiert, implementiert und betreibt Teilprojekt (TP) Verzeichnisdienst ein hochschulweites Identity & Access Management (I&AM) System, das eine Vielzahl daran angebundener Systeme und IT-Dienste mit aktuellen, autoritativen Daten über alle für sie relevanten Benutzer der TUM versorgt. Dabei wurden sowohl auf andere Hochschulen übertragbare Architekturen und Werkzeuge geschaffen als auch eine sehr präzise auf die Prozesse und Anforderungen der TUM abgestimmte Instanz realisiert, die auf Basis der im sehr erfolgreichen praktischen Betrieb gewonnenen Erfahrungen kontinuierlich verbessert und weiterentwickelt wurde. In diesem Artikel werden die Zielsetzung des Teilprojekts, die technische Architektur des I&AMSystems, ausgewählte Aspekte der Hochschul-Prozessintegration, Implementierungs-, Migrations- und Betriebsaspekte sowie die umfassenden Aktivitäten zum Know-How-Transfer von TP Verzeichnisdienst vorgestellt.

  10. 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

  11. Untersuchung der Störwirkung von LTE auf SRD Anwendungen bei 868 MHz

    NASA Astrophysics Data System (ADS)

    Welpot, M.; Wunderlich, S.; Gaspard, I.

    2014-11-01

    Moderne Hausautomatisierungssysteme, Alarmanlagen oder auch Funk-Zugangssysteme in Haus und Automobil setzen auf frei nutzbare Frequenzen in ISM/SRD-Bändern. Die rasante Zunahme an privaten und kommerziell genutzten Applikationen im SRD-Band bei 868 MHz und der Ausbau der LTE-Mobilfunknetze im Frequenzbereich unterhalb von 1 GHz ("Digital Dividend") wirft zunehmend die Frage nach der Funkverträglichkeit dieser Systeme untereinander auf. Während die SRD-Funkmodule auf eine geringe Sendeleistung von ~ +14 dBm beschränkt sind (Ralf and Thomas, 2009), beträgt die maximale LTE-Sendeleistung im Uplink nach (ETSI-Norm, 2011) +23 dBm. Zusammen mit der Einführung von LTE im Frequenzbereich unterhalb 1 GHz als DSL-Ersatz vor allem in ländlichen Gebieten, ergibt sich damit als mögliches Störszenario, dass durch die Aussendung des LTE-Endgerätes im Bereich von ca. 850 MHz die SRD-Funkverbindungen bei 868 MHz insbesondere dann gestört werden, wenn die Antennen beider Funksysteme räumlich nahe zueinander angeordnet sind und folglich nur eine geringe zusätzliche Entkopplung der Systeme bieten. In der vorliegenden Arbeit wird das LTE-Störpotential auf SRD-Empfänger praxisnah untersucht.

  12. FORS am Very Large Telescope der Europäischen Südsternwarte

    NASA Astrophysics Data System (ADS)

    1998-09-01

    Erstes wissenschaftliches Beobachtungsinstrument liefert eindrucksvolle Bilder Entsprechend dem straffen Zeitplan wird das ESO Very Large Teleskop Projekt (VLT-Projekt) auf dem Cerro Paranal in Nord-Chile verwirklicht: die volle Betriebsbereitschaft des ersten der vier 8,2m-Einzelteleskope wird Anfang des nächsten Jahres erreicht sein. Am 15. September 1998 wurde ein weiterer wichtiger Meilenstein erfolgreich, rechtzeitig und innerhalb des Kostenplans erreicht. Nur wenige Tage nach seiner Montage am ersten 8,2m-Einzelteleskop des VLT (UT1) konnte FORS1 ( FO cal R educer and S pectrograph) als erstes einer Gruppe leistungsfähiger und komplexer wissenschaftlicher Instrumente seine Beobachtungstätigkeit beginnen. Von Anfang an konnte es eine Reihe exzellenter astronomischer Bilder aufnehmen. Dieses bedeutende Ereignis eröffnet eine Fülle neuer Möglichkeiten für die europäische Astronomie. FORS - ein Höhepunkt an Komplexität FORS1 und das zukünftige Zwillingsinstrument (FORS2) sind das Ergebnis einer der eingehendsten und fortschrittlichsten technologischen Studien, die je für ein Instrument der bodengebundenen Astronomie durchgeführt wurden. Dieses einzigartige Instrument ist nun im Cassegrain-Fokus installiert und verschwindet beinahe, trotz seiner Dimensionen von 3 x 1.5m (Gewicht 2.3t), unterhalb des riesigen 53 m 2 großen Zerodurspiegels. Um die große Spiegelfläche und die hervorragende Bildqualität von UT1 optimal auszunützen, wurde FORS speziell so konstruiert, daß es die lichtschwächsten und entferntesten Objekte im Weltall untersuchen kann. Bald wird dieses komplexe VLT-Instrument den europäischen Astronomen erlauben, die derzeitigen Beobachtungshorizonte entscheidend zu erweitern. Die beiden FORS-Instrumente sind Vielzweck-Beobachtungsinstrumente, die in mehreren unterschiedlichen Beobachtungsarten eingesetzt werden können. Beispielsweise können Bilder mit zwei verschiedenen Abbildungsmaßstäben (Vergrößerungen) sowie Spektren mit

  13. Teaching ``The Physics of Energy'' at MIT

    NASA Astrophysics Data System (ADS)

    Jaffe, Robert

    2009-05-01

    New physics courses on energy are popping up at colleges and universities across the country. Many require little or no previous physics background, aiming to introduce a broad audience to this complex and critical problem, often augmenting the scientific message with economic and policy discussions. Others are advanced courses, focussing on highly specialized subjects like solar voltaics, nuclear physics, or thermal fluids, for example. About two years ago Washington Taylor and I undertook to develop a course on the ``Physics of Energy'' open to all MIT students who had taken MIT's common core of university level calculus, physics, and chemistry. By avoiding higher level prerequisites, we aimed to attract and make the subject relevant to students in the life sciences, economics, etc. --- as well as physical scientists and engineers --- who want to approach energy issues in a sophisticated and analytical fashion, exploiting their background in calculus, mechanics, and E & M, but without having to take advanced courses in thermodynamics, quantum mechanics, or nuclear physics beforehand. Our object was to interweave teaching the fundamental physics principles at the foundations of energy science with the applications of those principles to energy systems. We envisioned a course that would present the basics of statistical, quantum, and fluid mechanics at a fairly sophisticated level and apply those concepts to the study of energy sources, conversion, transport, losses, storage, conservation, and end use. In the end we developed almost all of the material for the course from scratch. The course debuted this past fall. I will describe what we learned and what general lessons our experience might have for others who contemplate teaching energy physics broadly to a technically sophisticated audience.

  14. Evaluation der zentralen TUM-Lernplattform

    NASA Astrophysics Data System (ADS)

    Schulze, Elvira; Baume, Matthias; Graf, Stephan; Gergintchev, Ivan

    Die Notwendigkeit der Qualitätssicherung und -kontrolle für innovative universitäre Lehr-/Lernszenarien ist in der Praxis unbestritten. Die Wirksamkeit der Einführung der zentralen Lernplattform CLIX Campus der imc AG an der TUM wurde mittels quantitativer und qualitativer Evaluation überprüft. Als statistische Bewertungsgrundlage wurde der Erreichungsgrad bestimmter Projektziele herangezogen. Aufbauend auf den theoretischen Grundlagen der Evaluation von Bildungsangeboten gibt diese Studie Aufschluss über die Ergebnisse der Datenerhebungen sowie die Einschätzung der Plattform aus Nutzersicht und belegt die wesentliche Bedeutung der durchgängigen IT-Infrastruktur und speziell der einheitlichen Verfügbarkeit der eLearning Angebote.

  15. Final Technical Report for the MIT Annular Fuel Research Project

    SciTech Connect

    Mujid S. Kazimi; Pavel Hejzlar

    2008-01-31

    MIT-NFC-PR-082 (January 2006) Abstract This summary provides an overview of the results of the U.S. DOE funded NERI (Nuclear Research ENergy Initiative) program on development of the internally and externally cooled annular fuel for high power density PWRs. This new fuel was proposed by MIT to allow a substantial increase in poer density (on the order of 30% or higher) while maintaining or improving safety margins. A comprehensive study was performed by a team consisting of MIT (lead organization), Westinghuse Electric Corporation, Gamma Engineering Corporation, Framatome ANP(formerly Duke Engineering) and Atomic Energy of Canada Limited.

  16. Neue Entwicklungen in der Berufsdermatologie.

    PubMed

    Diepgen, Thomas L

    2016-09-01

    Berufsbedingte Hautkrankheiten nach BK-Nr. 5101 stehen in Deutschland seit vielen Jahren an der Spitze der angezeigten Berufskrankheiten. Durch die Optimierung von Maßnahmen der primären, sekundären und tertiären Prävention können heutzutage die meisten Betroffenen im Beruf verbleiben. Zum 01.01.2015 wurde die Berufskrankheitenverordnung (BKV) novelliert und es wurde die BK-Nr. 5103 "Plattenepithelkarzinome oder multiple aktinische Keratosen der Haut durch natürliche UV-Strahlung" als neue Berufskrankheit in die BK-Liste der BKV aufgenommen. Die Definition von "multipel" bedeutet dabei entweder mehr als fünf einzelne aktinische Keratosen innerhalb eines Zeitraums von 12 Monaten oder das Vorliegen einer Feldkanzerisierung von größer 4 cm(2) . Wichtige Aspekte dieser neuen Berufskrankheit werden aufgezeigt und diskutiert sowie Neuerungen bei der BK 5101 angesprochen. PMID:27607028

  17. MIT ASTROMAG 1.7 meter disk magnet design report

    NASA Technical Reports Server (NTRS)

    Marston, P. G.; Hale, J. R.; Vieira, R.; Zhukovsky, A.; Titus, P. H.; Sullivan, J. D.; Dawson, A. M.

    1990-01-01

    MIT has proposed a magnet design for ASTROMAG, which has demonstrated substantial improvement in performance as compared with the present HEAO baseline design. Several advantages of the MIT disk design are listed along with design characteristics. Details of field contours and active field regions are shown along with comparisons with other designs. Three alternative design configurations for the ASTROMAG disk coils are summarized. The parameters of the conductors are listed and basic parameters for each of the complete systems are shown.

  18. Entwicklung von umwelt- und naturschutzgerechten Verfahren der landwirtschaftlichen Landnutzung für das Biosphärenreservat Schorfheide-Chorin

    NASA Astrophysics Data System (ADS)

    Meyer-Aurich, Andreas

    1999-11-01

    Mit der vorliegenden Arbeit werden exemplarisch Chancen und Grenzen der Integration von Umwelt- und Naturschutz in Verfahren der ackerbaulichen Landnutzung aufgezeigt. Die Umsetzung von Zielen des Umwelt- und Naturschutzes in Verfahren der Landnutzung ist mit verschiedenen Schwierigkeiten verbunden. Diese liegen zum einen in der Konkretisierung der Ziele, um diese umsetzen zu können, zum anderen in vielfach unzulänglichem Wissen über den Zusammenhang zwischen unterschiedlichen Formen der Landnutzung und insbesondere den biotischen Naturschutzzielen. Zunächst wird die Problematik der Zielfestlegung und Konkretisierung erörtert. Das Umweltqualitätszielkonzept von Fürst et al. (1992) stellt einen Versuch dar, Ziele des Umwelt- und Naturschutzes zu konkretisieren. Dieses Konzept haben Heidt et al. (1997) auf einen Landschaftsausschnitt von ca. 6000 ha im Biosphärenreservat Schorfheide-Chorin im Nordosten Brandenburgs angewendet. Eine Auswahl der von Heidt et al. (1997) formulierten Umweltqualitätsziele bildet die Basis dieser Arbeit. Für die ausgewählten Umweltqualitätsziele wurden wesentliche Einflussfaktoren der Landnutzung identifiziert und ein Bewertungssystem entwickelt, mit dem die Auswirkungen von landwirtschaftlichen Anbauverfahren auf diese Umweltqualitätsziele abgebildet werden können. Die praktizierte Landnutzung von 20 Betrieben im Biosphärenreservat Schorfheide-Chorin wurde von 1994 bis 1997 hinsichtlich ihrer Auswirkungen auf die Umweltqualitätsziele analysiert. Die Analyse ergab ein sehr differenziertes Bild, das zum Teil Unterschiede in der Auswirkung auf die Umweltqualitätsziele für den Anbau einzelner Kulturen oder für bestimmte Betriebstypen zeigte. Es zeigte sich aber auch, dass es bei der Gestaltung des Anbaus einzelner Kulturarten große Unterschiede gab, die für Umweltqualitätsziele Bedeutung haben. Neben der Analyse der Landnutzung im Biosphärenreservat Schorfheide-Chorin wurde ein System entwickelt, mit dem die modellhafte

  19. Satellitengeodäsie und Langbasis-Interferometrie auf der Fundamentalstation Wettzell. Kolloquiumsvorträge anläßlich des 60sten Geburtstages von Prof. Manfred Schneider.

    NASA Astrophysics Data System (ADS)

    Ilk, K.-H.

    Contents: Die krumme Geodäte (H. Ruder, M. Ruder). Zur Geschichte der Fundamentalstation Wettzell (H. Seeger et al.). Newtons Philosophiae naturalis principia mathematica (M. Schramm). Von Newton zu Einstein (M. H. Soffel). Geodäsie und Physik (S. Heitz). Erdbebenvorhersage mit SEISMOLAP (J. Zschau).

  20. Ein statistisches Modell zum Einfluß der thermischen Bewegung auf NMR-Festkörperspektren

    NASA Astrophysics Data System (ADS)

    Ploss, W.; Freude, D.; Pfeifer, H.; Schmiedel, H.

    Es wird ein statistisches Modell zum Einfluß der thermischen Bewegung auf die NMR-Linienform vorgestellt, das die Verschmälerung von Festkörper-Spektren bei wachsender Temperatur beschreibt. Das Modell geht von der Annahme aus, daß nach einer Ortsveränderung eines Kerns infolge thermischer Bewegung jede beliebige Kernresonanzfrequenz mit der durch das Festkörperspektrum vorgegebenen Wahrscheinlichkeit angenommen werden kann. Am Beispiel der Festkörper-Gaußlinie wird der Unterschied zu dem bekannten Modell von ANDERSON und WEISS verdeutlicht.Translated AbstractA Statistical Model for the Influence of Thermal Motion on N. M. R. Spectra in SolidsA theory is proposed which allows to describe the narrowing of n. m. r.-line width in the presence of thermal motions of the spins. The model is based on the assumption, that the local resonance frequency of a given spin immediately after the jump is distributed according to the n. m. r.-line shape of the rigid lattice. The difference to the well-known ANDERSON-WEISS-model of spectral narrowing is demonstrated for a gaussian line shape.

  1. Das Programm Oder 2006. Hochwasserschutz in Polen im Zuge der EU-Osterweiterung

    NASA Astrophysics Data System (ADS)

    Kühne, Olaf

    Hochwasser ist ein natürliches Ereignis: Seit jeher sind die Menschen mit Hochwasser und seinen Auswirkungen konfrontiert. Das Ausmaß von Hochwasser reicht dabei von Straßenüberschwemmungen bis zur Überflutung ganzer Landesteile. Auch im Oderflußsystem waren und sind Überschwemmungen keine Seltenheit, in den letzten 200 Jahren ereigneten sie sich in den Jahren 1813, 1838, 1854, 1870, 1903, 1958, 1965, 1970, 1972, 1977, 1981, 1985 und 1997. Das Hochwasser von 1997 war jedoch das schwerste im genannten Zeitraum. Als Reaktion auf das Hochwasser von 1997 wurde in der betroffenen Region das Programm 〝Oder 2006`` entwickelt. Mit seiner Hilfe sollen die Auswirkungen künftiger Hochwasserereignisse abgeschwächt werden.

  2. Kosten der Renaturierung

    NASA Astrophysics Data System (ADS)

    Hampicke, Ulrich

    Die Kapitel 3 bis 14 dieses Buches verdeutlichen die Verschiedenartigkeit der Renaturierungsprozesse in unterschiedlichen Ökosystemen und lassen keinen Zweifel daran, dass deren Kosten auch sehr weit auseinanderklaffen können. Die Kosten können gering sein, wenn die Renaturierung nur darin besteht, ein Biotop, das niemand braucht, sich selbst zu überlassen. Sie können aber auch sehr hoch sein, wenn etwa Sedimente eines Sees ausgebaggert und als Sondermüll entsorgt und aufwändige Klärkapazitäten installiert werden müssen.

  3. Der Strahlenkranz im sonnigen Wasser

    NASA Astrophysics Data System (ADS)

    Schlichting, Hans Joachim

    2000-01-01

    Wie in der Kunst gibt es auch in der Natur neben dem kreisförmigen Heiligenschein einen strahlenförmigen Nimbus um den Kopfschatten "auserwählter" Personen. Er ist in leicht getrübtem Wasser zu beobachten.

  4. Zeit im Wandel der Zeit.

    NASA Astrophysics Data System (ADS)

    Aichelburg, P. C.

    Contents: Einleitung(P. C. Aichelburg). 1. Über Zeit, Bewegung und Veränderung (Aristoteles). 2. Ewigkeit und Zeit (Plotin). 3. Was ist die Zeit? (Augustinus). 4. Von der Zeit (Immanuel Kant). 5. Newtons Ansichten über Zeit, Raum und Bewegung (Ernst Mach). 6. Über die mechanische Erklärung irreversibler Vorgänge (Ludwig Boltzmann). 7. Das Maß der Zeit (Henri Poincaré). 8. Dauer und Intuition (Henri Bergson). 9. Die Geschichte des Unendlichkeitsproblems (Bertrand Russell). 10. Raum und Zeit (Hermann Minkowski). 11. Der Unterschied von Zeit und Raum (Hans Reichenbach). 12. Newtonscher und Bergsonscher Zeitbegriff (Norbert Wiener). 13. Die Bildung des Zeitbegriffs beim Kinde (JeanPiaget).14. Eine Bemerkung über die Beziehungen zwischen Relativitätstheorie und der idealistischen Philosophie (Kurt Gödel). 15. Der zweite Hauptsatz und der Unterschied von Vergangenheit und Zukunft (Carl Friedrich v. Weizsäcker). 16. Zeit als physikalischer Begriff (Friedrich Hund). 17. Zeitmessung und Zeitbegriff in der Astronomie (Otto Heckmann). 18. Kann die Zeit rückwärts gehen? (Martin Gardner). 19. Zeit und Zeiten (Ilya Prigogine, Isabelle Stengers). 20. Zeit als dynamische Größe in der Relativitätstheorie (P. C. Aichelburg).

  5. Über den Einfluß von Wirbelströmen auf die Frequenzabhängigkeit der komplexen Permeabilität hochpermeabler Mangan-Zink-Ferrite

    NASA Astrophysics Data System (ADS)

    Dietzmann, G.; Schaefer, M.

    Nach der Einleitung, in der die Bedeutung der Wirbelströme für den Anstieg der Verluste mit der Frequenz in hochpermeablen Mn-Zn-Ferriten dargelegt wird, werden in Abschn. 2 gemessene Ortskurven der komplexen Permeabilität von Mn-Zn-Ferriten mit Werten der Anfangspermeabilität von 4000 bis 8000 und des spezifischen Widerstandes von 7 bis 138 cm (bei R. T.) vorgestellt. In Abschn. 3 wird der Versuch erläutert, einen gewissen Anfangsteil dieser Ortskurve durch theoretische Wirbelstromortskurven der komplexen Permeabilität, bei denen die Relaxation der komplexen Leitfähigkeit in Form eines von GRANT angegebenen Ausdruckes berücksichtigt ist, wiederzugeben. Die Ergebnisse, die in Abschn. 4 diskutiert werden, erlauben den Schluß, daß die mit der Relaxation der Leitfähigkeit verknüpften kapazitiven Wirbelströme für den Charakter des Anfangsverlaufes der an Ringkernen gemessenen Ortskurven der komplexen Permeabilität von hochpermeablen Mn-Zn-Ferriten bestimmend sein können.Translated AbstractOn the Effect of Eddy Currents on the Magnetic Spectra of High-permeability Manganese-zinc FerritesAfter stressing the importance of eddy currents on the increase of magnetic losses with frequency on high-permeability Mn-Zn-ferrites (in the introduction), experimental curves in the complex plane of the variation of the complex permeability with frequency of Mn-Zn-Ferrites with an initial permeability of 4000 up to 8000 and resistivity of 7 up to 130 ohm . cm are presented in section 2. In section 3 the attempt is stated of reproducing a certain initial part of the curve of complex permeability by theoretical eddy current curves, taking into account the relaxation of complex conductivity in form of an expression given by GRANT. The results discussed in section 4 permit the conclusion, that the capacitive eddy currents due to the relaxation of conductivity may be the essential factor determining the character of the initial turn of the complex magnetic dispersion curve

  6. Ökologische Grundlagen und limitierende Faktoren der Renaturierung

    NASA Astrophysics Data System (ADS)

    Rosenthal, Gert; Eichberg, Carsten

    In den dicht besiedelten und agrarisch besonders intensiv genutzten Regionen Mittel- und Westeuropas ist seit Ende des Zweiten Weltkrieges ein fortschreitender Verlust an naturnahen ökosystemen mit hoher biologischer Vielfalt zu verzeichnen. Spätestens seit den 1970er-Jahren ist daher die Neuschaffung und Wiederherstellung gefährdeter Lebensräume und Biozönosen zunehmend in den Mittelpunkt von Naturschutzmaßnahmen gerückt (Bakker 1989, Muller et al. 1998, Bakker und Berendse 1999). Aufgrund fehlender wissenschaftlicher Grundlagen und praktischer Erfahrungen wurden Renaturierungsmaßnahmen anfangs fast durchweg nach dem trial and error-Prinzip durchgeführt. Im Vordergrund standen dabei zunächst die Wiederherstellung adäquater abiotischer Standortbedingungen sowie die Reorganisation traditioneller Nutzungsmanagements. Bei Ersterem ging es neben der Wiedervernässung entwässerter Feuchtgebiete (Pfadenhauer und Grootjans 1999) vor allem darum, Eutrophierungseffekte zu beseitigen und die Produktivität des Standortes auf das Niveau der Zielgemeinschaft zurückzuführen (Gough und Marrs 1990, Oomes et al. 1996, Snow et al. 1997, Tallowin et al. 1998).

  7. Die Amtliche Sammlung von Untersuchungsverfahren nach § 64 LFGB, § 35 Vorläufiges Tabakgesetz und § 28b Gentechnikgesetz - ein Instrument der amtlichen Lebensmittelüberwachung

    NASA Astrophysics Data System (ADS)

    Renger, Silke; Stachel, Carolin

    Immer wieder werden Skandale in Zusammenhang mit Lebensmitteln bekannt. Schlagworte wie BSE, Gammelfleisch, Acrylamid, Cumarin oder auch Melamin, Dioxin sind den Verbrauchern geläufig und erschüttern das Vertrauen in ein gesundes und ernährungsphysiologisch wertvolles Lebensmittel. Das Bewusstsein des Verbrauchers hinsichtlich der Ernährung und der Auswahl beim Kauf der Lebensmittel hat sich in den vergangenen Jahren deutlich verändert. Bei der Auswahl seiner Lebensmittel liegt sein Augenmerk verstärkt auf gesunden, qualitativ hochwertigen und vor allem sicheren Lebensmitteln. Dies wurde insbesondere bei dem verhaltenen Kauf von Fleisch und Fleischerzeugnissen während der BSE-Krise oder auch dem kürzlich aufgetretenen Gammelfleischskandal deutlich.

  8. [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

  9. Klassifikation von Standardebenen in der 2D-Echokardiographie mittels 2D-3D-Bildregistrierung

    NASA Astrophysics Data System (ADS)

    Bergmeir, Christoph; Subramanian, Navneeth

    Zum Zweck der Entwicklung eines Systems, das einen unerfahrenen Anwender von Ultraschall (US) zur Aufnahme relevanter anatomischer Strukturen leitet, untersuchen wir die Machbarkeit von 2D-US zu 3D-CT Registrierung. Wir verwenden US-Aufnahmen von Standardebenen des Herzens, welche zu einem 3D-CT-Modell registriert werden. Unser Algorithmus unterzieht sowohl die US-Bilder als auch den CT-Datensatz Vorverarbeitungsschritten, welche die Daten durch Segmentierung auf wesentliche Informationen in Form von Labein für Muskel und Blut reduzieren. Anschließend werden diese Label zur Registrierung mittels der Match-Cardinality-Metrik genutzt. Durch mehrmaliges Registrieren mit verschiedenen Initialisierungen ermitteln wir die im US-Bild sichtbare Standardebene. Wir evaluierten die Methode auf sieben US-Bildern von Standardebenen. Fünf davon wurden korrekt zugeordnet.

  10. Das Vakuum kommt zu Kräften: Der Casimir-Effekt

    NASA Astrophysics Data System (ADS)

    Lambrecht, Astrid

    2005-03-01

    Die Casimir-Kraft zwischen zwei Spiegeln im Vakuum wird durch Vakuumfluktuationen verursacht. Dieser bedeutende Effekt ermöglicht es, in präzisen Laborversuchen unser Verständnis vom Quantenvakuum zu vertiefen. Eine Vielzahl neuer Experimente setzt dazu moderne Techniken wie die atomare Kraftmikroskopie oder mikroelektromechanische Systeme ein. Auch die theoretischen Modelle werden verbessert, um diese Experimente realistischer nachzubilden. Bislang stimmen die experimentellen Daten gut mit den theoretischen Vorhersagen überein. Da der Casimir-Effekt auf kurzen Distanzen dominieren kann, wird er für die zukünftige Nanotechnik wichtig sein. Der Grundlagenforschung bietet er eine gute Möglichkeit, neue Theorien zur Vereinigung aller Kräfte zu überprüfen.

  11. Der evolutionäre Naturalismus in der Ethik

    NASA Astrophysics Data System (ADS)

    Kaiser, Marie I.

    Charles Darwin hat eindrucksvoll gezeigt, dass der Mensch ebenso wie alle anderen Lebewesen ein Produkt der biologischen Evolution ist. Die sich an Darwin anschließende Forschung hat außerdem plausibel gemacht, dass sich nicht nur viele der körperlichen Merkmale des Menschen, sondern auch (zumindest einige) seiner Verhaltensdispositionen in adaptiven Selektionsprozessen herausgebildet haben. Die Vorstellung, dass auch die menschliche Moralität evolutionär bedingt ist, scheint daher auf den ersten Blick ganz überzeugend. Schließlich hat die Evolutionstheorie in den vergangenen Jahrzehnten in vielen Bereichen (auch außerhalb der Biologie) ihre weitreichende Bedeutung unter Beweis gestellt. Warum sollte, so könnte man beispielsweise fragen, gerade die Fähigkeit des Menschen, moralische Normen aufzustellen und gemäß ihnen zu handeln, nicht evolutionär erklärt werden können? Und warum sollte eine solche evolutionäre Erklärung der menschlichen Moralität irrelevant für die Rechtfertigung moralischer Normen sein? Warum sollte die Ethik eine Bastion der Philosophen bleiben, für die evolutionsbiologische Forschungsergebnisse über den Menschen und seine nächsten Verwandten keinerlei Relevanz besitzen?

  12. Education Outreach at MIT Plasma Science and Fusion Center

    NASA Astrophysics Data System (ADS)

    Censabella, V.; Rivenberg, P.

    1999-11-01

    Outreach at the MIT PSFC consists of volunteers working together to increase the public's knowledge of fusion and plasma-related experiments. Seeking to generate excitement about science, engineering and mathematics, the PSFC holds a number of outreach activities throughout the year, such as Middle and High School Outreach Days. Outreach also includes the Mr. Magnet Program, which uses an interactive strategy to engage elementary school children. The PSFC maintains a Home Page on the World Widee Web, which can be reached at http://psfc.mit.edu.

  13. MIT Mints a Valuable New Form of Academic Currency

    ERIC Educational Resources Information Center

    Carey, Kevin

    2012-01-01

    The Massachusetts Institute of Technology (MIT) has invented or improved many world-changing things--radar, information theory, and synthetic self-replicating molecules, to name a few. Last month the university announced, to mild fanfare, an invention that could be similarly transformative, this time for higher education itself. It is called MITx.…

  14. MIT Orients Course Materials Online to K-12

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2008-01-01

    Many science and mathematics educators across the country are taking advantage of a Web site created by the Massachusetts Institute of Technology (MIT), the famed research university located in Cambridge, Massachusetts, which offers free video, audio, and print lectures and course material taken straight from the school's classes. Those resources…

  15. Charakterisierung von Sulfotransferasen im Gastrointestinaltrakt von Mensch und Ratte und Aktivierung von Promutagenen in V79-Zellen, die eine intestinale Form (1B1) des Menschen und der Ratte exprimieren

    NASA Astrophysics Data System (ADS)

    Teubner, Wera

    2001-05-01

    Die Ausstattung der gastrointestinalen Mukosa des Menschen und der Ratte mit Sulfotransferasen wurde mit Hilfe von Immunodetektion und Enzymaktivitätsmessungen untersucht. In Proben aus Colon und Rektum von 39 Personen wurden die Formen h1A1, h1A3 und h1B1 identifiziert, wobei in einer weiteren Probe, die als einzige von einem an Colitis Ulcerosa erkrankten Patienten stammte, keine Sulfotransferasen nachgewiesen werden konnten. Bei der Immunblot-Analyse war das Expressionsmuster der einzelnen Formen in allen Proben ähnlich. In wenigen Proben waren die relativen Signalintensitäten der h1A1 und der h1B1 um die Hälfte erniedrigt. Der Gehalt von SULT an zytosolischem Protein zeigte einen bis zu 8 - 10fachen Unterschied, er betrug jedoch bei zwei Dritteln der Proben zwischen 0,15 und 0,3 (h1A1 und h1A3) bzw. 0,6 und 0,8 Promille (h1B1). Die Variation konnte nicht auf Alter, Geschlecht oder Krankheitsbild der Patienten zurückgeführt werden. Auch der für die allelischen Varianten der h1A1 beschriebene Effekt auf die Enzymaktiviät bzw. Stabilität konnte in der Menge an immunreaktivem Protein nicht in diesem Ausma detektiert werden. Die Allelhäufigkeit von h1A1*R und h1A1*H war gegenüber der gesunden Bevölkerung nicht verändert. In den sieben Proben aus dem Dünndarm (Coecum, viermal Ileum, Jejunum) konnten zusätzlich die Formen h1E1 und h2A1 identifiziert werden. Ein möglicherweise der Form h1C1 entsprechendes Protein wurde im Magen detektiert. Im Vergleich zum Menschen war die Expression in der Ratte stärker auf die Leber konzentriert. Während beim Menschen in allen untersuchten Abschnitten Sulfotransferasen in Mengen detektiert wurden, die in zwei Fällen (h1B1 und h1A3) sogar den Gehalt in der Leber überstiegen, beschränkte sich die Expression in der Ratte auf im Vergleich zur Leber geringe Mengen im Magen und Dickdarm. Nachgewiesen wurden die r1B1, r1A1 sowie eine nicht identifizierte Form von 35kD, bei der es sich vermutlich um die r1C2 handelt. Im

  16. Sinn und Möglichkeiten der Theoretischen Physik. Zum 300. Jahrestag von Newtons Philosophiae Naturalis Principia Mathematica

    NASA Astrophysics Data System (ADS)

    Rompe, R.; Thiessen, P. A.; Treder, H.-J.

    Die Newtonschen Prinzipien und die aus ihnen gewonnene Erkenntnis der Existenz von Elementarkonstanten nach Planck, Einstein und Bohr erweisen sich zunehmend als tragfähiges Fundament nicht nur der Physik und ihrer Anwendung in der Technik, sondern überhaupt aller exakten Wissenschaften in breitestem Sinne des Wortes.Die physikalisch inhaltliche Klärung der Begriffe erfolgt seit Newton in engem Verbund mit der Entwicklung mathematischer Methoden. Diese Kombination erweist sich weiterhin als produktiv und sichert den Fortschritt der Physik und der exakten Wissenschaften.Wohl alle Probleme, die im Bereich der Technik Bedeutung haben können, lassen sich bei entsprechendem Aufwand bereits mit dem vorhandenen Fundus an Erkenntnissen und Methoden erfolgreich angehen.Der in der Wirklichkeit verankerte Zusammenhang von Gesetz und Zufall erweist sich als eine Manifestation der Dialektik in der Natur. Es gibt keinen absoluten Zufall. Sie kommt in allen Zweigen der Physik, nicht nur in der Thermodynamik und Quantenphysik, zutage, und muß bereits auf dem Niveau der Newtonschen Prinzipien und der Elementarkonstanten behandelt werden.Die theoretische Physik, so wie sie von Newton initiiert worden ist, wurde so angelegt, daß sie alle Seiten der Wirklichkeit, so weit sie in die Kompetenz der Physik fallen, umfaßt. Es besteht darum kein Gegensatz zwischen der klassischen Physik und der Quantenphysik. Es handelt sich lediglich um eine Differenzierung nach den unterschiedlichen physikalischen Inhalten und den angemessenen mathematischen Methoden, die natürlich von der Wahl der Probleme abhängen.Die theoretische Physik stellt eine allgemein zugängliche Zusammenfassung des gesicherten Wissens der Physik dar, das zugleich das Fundament der exakten Wissenschaften ist.Die theoretische Physik ist damit das Mittel der Verständigung innerhalb der Kooperation, die notwendig ist zur Lösung der großen komplexen Aufgaben der Wissenschaft und Technik.

  17. Profiles of IgE Sensitization to Der f 1, Der f 2, Der f 6, Der f 8, Der f 10, and Der f 20 in Korean House Dust Mite Allergy Patients

    PubMed Central

    Jeong, Kyoung Yong; Lee, June Yong; Son, Mina; Yi, Myung-hee; Yong, Tai-Soon; Shin, Jung U; Lee, Kwang Hoon; Kim, Yoon-Ju; Park, Kyung Hee; Park, Hye Jung; Lee, Jae-Hyun

    2015-01-01

    Purpose Measurement of IgE specific to purified house dust mite (HDM) allergens may improve allergy diagnosis. This study aimed to investigate the sensitization profiles of Korean HDM allergic subjects suffering from respiratory allergy and atopic dermatitis (AD) to Der f 1, Der f 2, Der f 6, Der f 8, Der f 10, and Der f 20. Methods Recombinant HDM allergens were produced in Pichia pastoris (Der f 1) or Escherichia coli (5 allergens). IgE reactivity to the individual recombinant allergens and total extract of mite was assessed by ELISA. Results Der f 1 was recognized by 79.1%, Der f 2 by 79.1%, Der f 6 by 9.3%, Der f 8 by 6.2%, Der f 10 by 6.2%, and Der f 20 by 6.6% of the patients' sera tested, while the prevalence of IgE reactivity to total mite extract was 94.7%. Combination of Der f 1 and Der f 2 had a sensitivity of 87.6%. Specific IgE to Der f 2 alone was detected from 89.4% of HDM-sensitized respiratory allergy subjects and 92.3% to the combination of the 2 major allergens Der f 1 and Der f 2. However, sera from fewer patients with AD, namely 72.4% and 71.0%, recognized Der f 1 and Der f 2, respectively. The combination of 2 major allergens allowed diagnosis of 84.5% of the AD patients. No correlation between sensitization to specific allergens and HDM allergy entity was found. Conclusions Der f 2 was the most frequently sensitized allergen among the HDM-sensitized respiratory and AD patients in Korea, and the combination of the group 1 and 2 major allergens increased the diagnostic sensitivity. Minor allergens did not significantly improve diagnostic sensitivity. However, further studies are needed to analyze the relationship between sensitization to other HDM allergens and the disease entity of the HDM allergy. PMID:25749773

  18. Strategische Planung in der Medizintechnik

    NASA Astrophysics Data System (ADS)

    Leewe, Jörn

    Für den Aufstieg und den Niedergang der Unternehmen spielt die Über- oder Unterlegenheit der Technologie eine zentrale Rolle. Mindestens im gleichen Maße ist jedoch auch ein umsichtiges Management und eine sorgfältige strategische Planung für den Erfolg verantwortlich. Nur ein profitables Unternehmen, welches nachhaltige Gewinne erzielt, ist in der Lage, eine Spitzenforschung aus eigener Kraft zu finanzieren. Dies klingt zunächst trivial. In der langjährigen Consulting-Praxis sind wir jedoch diversen Unternehmen begegnet, die diese Maxime vernachlässigt haben und aufgrund mangelhafter Planungen eine Insolvenz dann nicht mehr abwenden konnten. Damit es erst gar nicht dazu kommt, sollten unterschiedliche Handlungsalternativen im voraus entwickelt und bewertet werden. Die Strategie, also das systematische Aufbauen von Wettbewerbsvorteilen, sollte regelmässig überprüft werden und eine finanzielle Entwicklung des Produktes oder des Unternehmens sollte regelmäßig antizipiert und simuliert werden. Dieser Beitrag soll Einblicke in die strategische Planung erlauben, erhebt allerdings aufgrund der Komplexität des Themas keinen Anspruch auf Vollständigkeit.

  19. 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.

  20. Das Lektin aus der Erbse Pisum sativum : Bindungsstudien, Monomer-Dimer-Gleichgewicht und Rückfaltung aus Fragmenten

    NASA Astrophysics Data System (ADS)

    Küster, Frank

    2002-11-01

    Das Lektin aus Pisum sativum, der Gartenerbse, ist Teil der Familie der Leguminosenlektine. Diese Proteine haben untereinander eine hohe Sequenzhomologie, und die Struktur ihrer Monomere, ein all-ß-Motiv, ist hoch konserviert. Dagegen gibt es innerhalb der Familie eine große Vielfalt an unterschiedlichen Quartärstrukturen, die Gegenstand kristallographischer und theoretischer Arbeiten waren. Das Erbsenlektin ist ein dimeres Leguminosenlektin mit einer Besonderheit in seiner Struktur: Nach der Faltung in der Zelle wird aus einem Loop eine kurze Aminosäuresequenz herausgeschnitten, so dass sich in jeder Untereinheit zwei unabhängige Polypeptidketten befinden. Beide Ketten sind aber stark miteinander verschränkt und bilden eine gemeinsame strukturelle Domäne. Wie alle Lektine bindet Erbsenlektin komplexe Oligosaccharide, doch sind seine physiologische Rolle und der natürliche Ligand unbekannt. In dieser Arbeit wurden Versuche zur Entwicklung eines Funktionstests für Erbsenlektin durchgeführt und seine Faltung, Stabilität und Monomer-Dimer-Gleichgewicht charakterisiert. Um die spezifische Rolle der Prozessierung für Stabilität und Faltung zu untersuchen, wurde ein unprozessiertes Konstrukt in E. coli exprimiert und mit der prozessierten Form verglichen. Beide Proteine zeigen die gleiche kinetische Stabilität gegenüber chemischer Denaturierung. Sie denaturieren extrem langsam, weil nur die isolierten Untereinheiten entfalten können und das Monomer-Dimer-Gleichgewicht bei mittleren Konzentrationen an Denaturierungsmittel auf der Seite der Dimere liegt. Durch die extrem langsame Entfaltung zeigen beide Proteine eine apparente Hysterese im Gleichgewichtsübergang, und es ist nicht möglich, die thermodynamische Stabilität zu bestimmen. Die Stabilität und die Geschwindigkeit der Assoziation und Dissoziation in die prozessierten bzw. nichtprozessierten Untereinheiten sind für beide Proteine gleich. Darüber hinaus konnte gezeigt werden, dass auch unter

  1. Der Begriff der Verständlichkeit in der modernen Physik (1948).

    PubMed

    Feyerabend, Paul K

    2016-06-01

    This is a critical transcription of Paul Feyerabend's earliest extant essay "Der Begriff der Verständlichkeit in der modernen Physik" (1948) recovered from the European Forum Alpbach archives. In it, Feyerabend defends positivism as a progressive framework for scientific research in certain stages of scientific development. He argues that in physics visualizability (Anschaulichkeit) and intelligibility (Verständlichkeit) are time-conditioned concepts: what is deemed visualizable in the development of physical theories is relative to a specific historical context and changes over time. He concludes that from time to time the abandonment of visualizability is crucial for progress in physics, as it is conducive to major theory change, illustrating the point on the basis of advances in atomic theory. PMID:27269264

  2. The Harvard-MIT PHD Program in Bioastronautics

    NASA Astrophysics Data System (ADS)

    Young, Laurence R.; Natapoff, Alan

    2008-06-01

    The National Space Biomedical Research Institute (NSBRI)1 supports a PhD program in Space Life Sciences with a specialty in Bioastronautics at MIT. (A sibling program operates at TAMU.) It gives broad training in life sciences, emphasizes hands-on field experience, provides access to laboratories in the Harvard-MIT community for thesis research, and prepares students for many options in space biomedicine. The Program trains prospective leaders in the field able to manage the challenges of design for the life-hostile space environment. Beyond subject and thesis work, students participate in a summer internship and a clinical preceptorship at a NASA center--and an introduction to clinical medicine and medical engineering.

  3. Wirkungen biogener Amine auf die Erregungs-Sekretions-Kopplung in der Speicheldrüse von Periplaneta americana (L.)

    NASA Astrophysics Data System (ADS)

    Rietdorf, Katja

    2003-07-01

    habe gefunden, dass die Aktivität der Na+-K+-ATPase wichtig für die Modifikation des DA-stimulierten Primärspeichels ist. Im Gegensatz dazu ist sie für die Modifikation des 5-HT-stimulierten Primärspeichels nicht von Bedeutung. Bezüglich der Flüssigkeitssekretion habe ich keinen Einfluss der Na+-K+-ATPase-Aktivität auf die DA-stimulierten Sekretionsraten gefunden, dagegen ist die 5-HT-stimulierte Sekretionsrate in Anwesenheit von Ouabain gesteigert. Die Aktivität des NKCC ist für beide sekretorische Prozesse, die Ionen- und die Flüssigkeitssekretion, wichtig. Eine Hemmung des NKCC bewirkt eine signifikante Verringerung der Raten der Flüssigkeitssekretion nach DA- und 5-HT-Stimulierung sowie in beiden Fällen einen signifikanten Abfall der Ionenkonzentrationen im Endspeichel. Im zweiten Teil meiner Arbeit habe ich versucht, Änderungen der intrazellulären Ionenkonzentrationen in den Acinuszellen während einer DA- oder 5-HT-Stimulierung zu messen. Diese Experimente sollten mit der Methode des "ratiometric imaging" durchgeführt werden. Messungen mit dem Ca2+-sensitiven Fluoreszenzfarbstoff Fura-2 zeigten keinen globalen Anstieg in der intrazellulären Ca2+-Konzentration der P-Zellen. Aufgrund von Problemen mit einer schlechten Beladung der Zellen, einer starken und sich während der Stimulierung ändernden Autofluoreszenz der Zellen sowie Änderungen im Zellvolumen wurden keine Messungen mit Na+- und K+-sensitiven Fluoreszenzfarbstoffen durchgeführt. Im dritten Teil dieser Arbeit habe ich die intrazellulären Signalwege untersucht, die zwischen einer 5-HT-Stimulierung der Drüse und der Proteinsekretion vermitteln. Dazu wurde der Proteingehalt im Endspeichel biochemisch mittels eines modifizierten Bradford Assay gemessen. Eine erstellte Dosis-Wirkungskurve zeigt, dass die Rate der Proteinsekretion von der zur Stimulierung verwendeten 5-HT-Konzentration abhängt. In einer Serie von Experimenten habe ich die intrazellulären Konzentrationen von Ca2+, c

  4. The Kubo-Greenwood expression and 2d MIT transport

    NASA Astrophysics Data System (ADS)

    Castner, Theodore

    2010-03-01

    The 2d MIT in GaAs heterostructures (p- and n-type)features a mobility that drops continuously as the reduced density x= n/nc-1 is decreased. The Kubo-Greenwood result [1] predicts μ = (eɛh/hnc)α^2(x) where α is a normalized DOS. α(x)is obtained from the data [p-type, Gao et al. [2]; n-type Lilly et al. [3

  5. Ancillary Services Provided from DER

    SciTech Connect

    Campbell, J.B.

    2005-12-21

    Distributed energy resources (DER) are quickly making their way to industry primarily as backup generation. They are effective at starting and then producing full-load power within a few seconds. The distribution system is aging and transmission system development has not kept up with the growth in load and generation. The nation's transmission system is stressed with heavy power flows over long distances, and many areas are experiencing problems in providing the power quality needed to satisfy customers. Thus, a new market for DER is beginning to emerge. DER can alleviate the burden on the distribution system by providing ancillary services while providing a cost adjustment for the DER owner. This report describes 10 types of ancillary services that distributed generation (DG) can provide to the distribution system. Of these 10 services the feasibility, control strategy, effectiveness, and cost benefits are all analyzed as in the context of a future utility-power market. In this market, services will be provided at a local level that will benefit the customer, the distribution utility, and the transmission company.

  6. Terror mit Atomwaffen: reale Gefahr? Nukleare und Radiologische Waffen

    NASA Astrophysics Data System (ADS)

    Harigel, Gert G.

    2006-01-01

    Können Terroristen sich nukleare Massenvernichtungswaffen beschaffen? Dazu müssten sie ausreichende Mengen an waffenfähigem, spaltbarem Material stehlen. Selbst der Bau einer primitiven Atombombe erfordert einen hohen technischen Aufwand und Spezialisten. Wahrscheinlicher ist deshalb der Diebstahl einer kleinen taktischen Kernwaffe. Alternativ könnten Terroristen sich radioaktives Material aus zivilen Quellen beschaffen und daraus eine Schmutzige Bombe bauen. Eine solche radiologische Waffe wäre keine echte Massenvernichtungswaffe, doch ihre psychologische Wirkung könnte stark sein. Das macht sie für Terroristen attraktiv, weswegen diese Gefahr ernst genommen werden muss.

  7. Kartenerstellung mit Geostatistik und Fuzzy-Geostatistik. Ein Methodenvergleich am Beispiel der Verteilung der Sulfatkonzentrationen im oberflächennahen Grundwasserleiter in Bremen Nord

    NASA Astrophysics Data System (ADS)

    Azouzi, Blel; Schröter, Jürgen

    2012-12-01

    In order to visualize sulfate contents distributions in near surface groundwater north of Bremen, maps were regionalized by Ordinary Kriging, Fuzzy Kriging and the Natural Neighbor method and compared with a conventionally provided distribution map. The computations were made with uniform parameters and a uniform raster grid. The original data sets contained fuzzy data of sulfate concentrations like "<40 mg/l", which were used in different variants for the interpolation. The regionalization of the sulfate concentrations by Ordinary Kriging shows—depending on the conversion of these values—strongly smoothed results, particularly within the range of locally arising concentration maxima in the southern investigation area. In comparison, the maps by Fuzzy Kriging and the Natural Neighbor method identified high concentration gradients much better. The Fuzzy Kriging approach links the quality of a geostatistical method with the possibility of dealing with imprecise data, and is therefore preferred in comparison to the other methods.

  8. Systeme mit veränderlicher Teilchenzahl, Gasentartung

    NASA Astrophysics Data System (ADS)

    Heintze, Joachim

    Bisher haben wir die Zustandsgrößen ν (Zahl der Mole) und N (Zahl der Teilchen im System) als konstant betrachtet. In diesem Kapitel wollen wir untersuchen, wie sich Veränderungen von ν bzw. von N beschreiben lassen. Dazu werden wir eine neue thermodynamische Größe einführen, das chemische Potential μ. Als Beispiele für die Veränderung von Teilchenzahlen werden wir diffusive Prozesse und chemische Reaktionen betrachten. Am Ende des Kapitels werden wir die quantenmechanische Gasentartung diskutieren, bei der das chemische Potential ebenfalls eine Rolle spielt. Wir werden feststellen, dass es nicht schwierig ist, einige Eigenschaften dieses interessanten Materiezustands zu verstehen. Wir behandeln das Thema bereits hier und nicht erst in der Quantenphysik am Ende des Buches, weil es in die Wärmelehre gehört und weil auf dieser Grundlage die elektrischen Eigenschaften von Metallen in Bd. III/9 leicht diskutiert werden können.

  9. Untergrundstörungen durch organische Lösungsmittel in der Atomabsorptionsspektrometrie mit Graphitöfen

    NASA Astrophysics Data System (ADS)

    Gücer, S.; Massmann, H.

    In atomic absorption spectrometry with graphite furnaces, marked background interferences may occur during the atomization step, when organic solvents are used. Aromatic molecules can sorb to the graphite, partly very firmly, so that they appear in the absorption volume only during the atomizing step, even after preceding interim heating to 800°C. The undissociated molecules show characteristic vibrational spectra in which bands with relative sharp edges can be observed. No rotational structure is recognizable. Reliable background measurements may prove problematic if not entirely impossible in some wavelength regions.

  10. Comments on the MIT Assessment of the Mars One Plan

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.

    2015-01-01

    The MIT assessment of the Mars One mission plan reveals design assumptions that would cause significant difficulties. Growing crops in the crew chamber produces excessive oxygen levels. The assumed in-situ resource utilization (ISRU) equipment has too low a Technology Readiness Level (TRL). The required spare parts cause a large and increasing launch mass logistics burden. The assumed International Space Station (ISS) Environmental Control and Life Support (ECLS) technologies were developed for microgravity and therefore are not suitable for Mars gravity. Growing food requires more mass than sending food from Earth. The large number of spares is due to the relatively low reliability of ECLS and the low TRL of ISRU. The Mars One habitat design is similar to past concepts but does not incorporate current knowledge. The MIT architecture analysis tool for long-term settlements on the Martian surface includes an ECLS system simulation, an ISRU sizing model, and an analysis of required spares. The MIT tool showed the need for separate crop and crew chambers, the large spare parts logistics, that crops require more mass than Earth food, and that more spares are needed if reliability is lower. That ISRU has low TRL and ISS ECLS was designed for microgravity are well known. Interestingly, the results produced by the architecture analysis tool - separate crop chamber, large spares mass, large crop chamber mass, and low reliability requiring more spares - were also well known. A common approach to ECLS architecture analysis is to build a complex model that is intended to be all-inclusive and is hoped will help solve all design problems. Such models can struggle to replicate obvious and well-known results and are often unable to answer unanticipated new questions. A better approach would be to survey the literature for background knowledge and then directly analyze the important problems.

  11. Real-time control of the MIT vehicle emulation system

    NASA Technical Reports Server (NTRS)

    Durfee, William K.; Idris, Husni R.; Dubowsky, Steven

    1991-01-01

    The MIT vehicle emulation system (VES) is an experimental facility designed to facilitate the study of controlling robots fixed to nonstationary bases. This includes assembly and repair manipulators attached to space vehicles, or to the space shuttle arm, as well as manipulators fixed to the bed of moving ground vehicles. Controlling manipulators under these conditions for endpoint force and positioning tasks requires both the development of new theory, and the development of a testbed for verifying theoretical results through experimentation. A description is presented of the technical details of the real-time controller for the second generation VES system.

  12. Research in Boron Neutron Capture Therapy at MIT LABA

    SciTech Connect

    Yanch, J.C.; Shefer, R.E.; Klinkowstein, R.E.; Howard, W.B.; Song, H.; Blackburn, B.; Binello, E.

    1997-02-01

    A 4.1 MeV tandem electrostatic accelerator designed for research into Boron Neutron Capture Therapy (BNCT) has recently been installed in the MIT Laboratory for Accelerator Beam Applications (LABA). This accelerator uses a very high current switch mode high voltage power supply in conjunction with a multi-cusp negative ion source to supply the multimilliampere current required for clinical BNCT applications. A number of individual research projects aimed at evaluating the potential of this accelerator design as a hospital-based neutron source for radiation therapy of both tumors and rheumatoid arthritis are described here. {copyright} {ital 1997 American Institute of Physics.}

  13. Characteristics of the MIT microwiggler for free electron laser applications

    SciTech Connect

    Catravas, P.; Stoner, R.; Bekefi, G.

    1995-12-31

    We report work on the development of microwiggler technology for free electron laser research. The MIT microwiggler is a pulsed electromagnet with 70 periods of 8.8 mm each which generates a peak on-axis field of 4.2 kG. The wiggler is characterized by extensive tunability. We developed a novel tuning regimen to control 140 degrees of freedom afforded by the individually tunable half periods and achieved an rms spread in the peak amplitudes of 0.08%. This is the lowest attained to date in any sub-cm period wiggler. The microwiggler design and comprehensive measurements of its characteristics will be described.

  14. Stabile Expression von Sulfotransferasen - allein oder in Kombination mit Cytochrom P450 - in Zelllinien für Mutagenitätsuntersuchungen

    NASA Astrophysics Data System (ADS)

    Pabel, Ulrike

    2003-10-01

    -dimethylaminoazobenzol; 0,1 µM für 2-Aminoanthracen; 10 µM für 2,4-Diaminotoluol). Die stärkste Aktivierung von 2-Acetylaminofluoren und 3′-Methyl-4-dimethylaminoazobenzol erfolgte in der Zelllinie, die CYP1A2 und SULT1A2 koexprimierte; die stärkste Aktivierung von 2,4-Diaminotoluol und 2-Aminoanthracen erfolgte in der Zelllinie, die CYP1A2 und SULT1A1 koexprimierte. Sowohl SULT1A1 als auch SULT1A2 sind im Menschen genetisch polymorph. Ein unterschiedlich starkes Aktivierungspotenzial der Alloenzyme könnte eine individuell unterschiedliche Suszeptibilität für die durch aAA ausgelöste Kanzerogenese bedingen. In HPRT-Mutationsuntersuchungen mit rekombinanten Zellen zeigten die allelischen Varianten der SULT1A2 starke Unterschiede in ihrem Aktivierungpotenzial. Nur in der Zelllinie, die das Alloenzym SULT1A2*1 mit CYP1A2 koexprimierte, wurde 2-Acetylaminofluoren zum Mutagen aktiviert. Zur Aktivierung von 3′-Methyl-4-dimethylaminoazobenzol waren jedoch sowohl das Alloenzym SULT1A2*1 als auch das Alloenzym SULT1A2*2 in der Lage. Die Alloenzyme der SULT1A1 zeigten ein ähnlich gutes Aktivierungspotenzial für aAA. In früheren Studien wurde gezeigt, dass die SULT1C1 der Ratte eine wichtige Rolle bei der Aktivierung der aAA in dieser Spezies spielt. Dahingegen war die humane SULT1C1 nicht in der Lage die untersuchten aAA zu aktivieren. Die Kenntnis solcher Spezieunterschiede könnte wichtig sein um unterschiedliche Organotropismen aAA in Menschen und Tiermodellen zu erklären, da SULT mit starker Gewebespezifität exprimiert werden und das Expressionsmuster für die einzelnen SULT-Formen in Menschen und Ratten sich stark unterscheidet. Aromatic amines and amides (aAA) represent a group of chemicals with great toxicological importance due to their wide distribution in the environment and their carcinogenic potency. The carcinogenicity of aAA is mediated by the mutagenic action of highly reactive metabolites. They are frequently formed by N-hydroxylation of the exocyclic

  15. Friedrich Möglich - sein Beitrag zum Aufbau der Physik in der DDR. Friedrich Möglich - langjähriger Mitherausgeber und Chefredakteur der Annalen der Physik

    NASA Astrophysics Data System (ADS)

    Rompe, Robert

    Friedrich Möglich, ein Schüler von Max von Laue und Erwin Schrödinger, übernahm 1947 die Chefredaktion der Annalen der Physik.Translated AbstractFriedrich Möglich - His Contributions to the Formation of Physics in GDRFriedrich Möglich a student of Max von Laue and Erwin Schrödinger took over as editor in chief of Annalen der Physik in 1947.

  16. Kosmische Weiten. Kurze Geschichte der Entfernungsmessung im Weltall.

    NASA Astrophysics Data System (ADS)

    Herrmann, D. B.

    Contents: 1. Einleitung. 2. Trigonometrische (jährliche) Fixsternparallaxen. 3. Fotometrische Parallaxen. 4. Überblick über weitere Methoden der Entfernungsbestimmung. 5. Entfernungen der extragalaktischen Objekte. 6. Ausblick. 7. Elementare Grundlagen der Entfernungsbestimmung.

  17. MIT Lincoln Laboratory: Physics and Technology in the National Interest

    NASA Astrophysics Data System (ADS)

    Ralston, Richard

    2001-03-01

    This year, MIT is celebrating the 50th anniversary of the founding of Lincoln Laboratory, which was formed at the request of the DoD with the initial goal of developing a national air defense system. In its 50 years, the Laboratory staff have made significant contributions in diverse areas including radar imaging, satellite communications, digital signal processing, computer science, semiconductor materials and solid state physics. The Laboratory has been true to its mission statement, which places strong emphasis on the application of advanced electronics to R&D in the national interest. Much of the technology is transitioned to U.S. industry for both government and commercial use. Annually more than 500 publications and meeting speeches are given, and cooperative developments with industry have targeted technology transitions ranging from next-generation photolithographic tools to microchip lasers. The Laboratory staff have been granted over 400 patents, and license to this intellectual property is at the core of many of the over 70 spin-off companies. MIT employs 2,300 people at Lincoln, including 1,200 professionals with degrees in physics, math, computer science, materials science and the engineering disciplines. Two-fifths of the professional staff are at the doctoral level; over two-thirds hold advanced degrees. This presentation will describe recent examples of research challenges for physicists in a multidisciplinary project-oriented environment.

  18. MIT nuclear reactor laboratory high school teaching program

    SciTech Connect

    Olmez, I. )

    1991-11-01

    For the last 6 years, the Massachusetts Institute of Technology (MIT) Nuclear Reactor Laboratory's academic and scientific staff{sup a} have been conducting evening seminars for precollege science teachers, parents, and high school students from the New England area. These seminars, as outlined in this paper, are intended to give general information on nuclear technologies with specific emphasis on radiation physics, nuclear medicine, nuclear chemistry, and ongoing research activities at the MIT research reactor. The ultimate goal is to create interest or build on the already existing interest in science and technology by, for example, special student projects. Several small projects have already been completed ranging from environmental research to biological reactions with direct student involvement. Another outcome of these seminars was the change in attitudes of science teachers toward nuclear technology. Numerous letters have been received from the teachers and parents stating their previous lack of knowledge on the beneficial aspects of nuclear technologies and the subsequent inclusion of programs in their curriculum for educating students so that they may also develop a more positive attitude toward nuclear power.

  19. Education Outreach at MIT Plasma Science Fusion Center

    NASA Astrophysics Data System (ADS)

    Censabella, V.; Nachtrieb, R.; Rivenberg, P.

    1998-11-01

    Outreach at the MIT PSFC consists of volunteers working together to increase the public's knowledge of fusion and plasma-related experiments. Seeking to generate excitement about science, engineering and mathematics, the PSFC holds a number of outreach activities throughout the year, such as Middle and High School Outreach Days. Outreach also includes the Mr. Magnet Program, which uses an interactive strategy to engage elementary school children. Included in this year's presentation will be a live demo of a compressed-air bottle rocket (really a one-liter plastic soda bottle) for use in high school science classrooms that researchers at the Cambridge Physics Outlet (a PSFC spin-off company) have developed. To prepare the rocket for launch, the bottle is filled with compressed air at pressures up to 80 psi and the end is plugged. The rocket is released when the plug is pulled. The gas escapes at supersonic velocities and accelerates the bottle at over 1000 m/s^2. The velocity of the bottle is measured at many locations along its ``trajectory". A simple thermodynamic model predicts performance in excellent agreement with observation. The PSFC maintains a Home Page on the World Wide Web, which can be reached at http://pfc.mit.edu.

  20. Von Humboldt bis Einstein. Berlin als Weltzentrum der exakten Wissenschaften.

    NASA Astrophysics Data System (ADS)

    Meschkowski, H.

    Contents: 1. Die Anfänge. 2. Die Ära Dirichlet-Jacobi. 3. Der Ausbau der experimentellen Naturwissenschaften. 4. Alexander von Humboldt. 5. Berlin wird "Weltzentrum" der Mathematik. 6. Die Ära Helmholtz. 7. Neue Arbeitsweisen der Astronomie. 8. Chemie: Forschung und Industrie. 9. Max Planck. 10. Ins technische Zeitalter. 11. Zur Mathematik der zwanziger Jahre. 12. Albert Einstein. 13. Fortschritte der Grundlagenforschung. 14. Erwin Schrödinger: Physiker, Philosoph und Poet. 15. Zum Schluß.

  1. Der Kalte Krieg in der Peripherie Griechische Physiker und Atomenergie nach dem Zweiten Weltkrieg

    NASA Astrophysics Data System (ADS)

    Vlahakis, George N.

    Die vorliegende Arbeit analysiert Ansichten griechischer Physiker zur Atomenergie und deren mögliche Anwendung nach dem Zweiten Weltkrieg, insbesondere während des Kalten Kriegs. Einerseits werden Ansichten von Physik- Professoren griechischer Universitäten präsentiert - beispielsweise von Dimitrios Hondros, der Student von Arnold Sommerfeld und Mitarbeiter von Peter Debye in München war, und andererseits wird die Politik der griechischen Regierung für die Etablierung eines Forschungsinstitutes diskutiert, das der Entwicklung der Atomenergie dienen sollte; ebenfalls wird eine öffentliche Meinungsumfrage zu diesen Thema, die in den Tageszeitungen der damaligen Zeit präsentiert wurde, diskutiert.

  2. M.I.T. and the Federal Government. An Examination of the Effects of Government Regulation and Research Support on Selected Parts of M.I.T.

    ERIC Educational Resources Information Center

    Garvin, David

    A self-study was undertaken at the Massachusetts Institute of Technology (M.I.T.) to examine the impact of the federal government on it. M.I.T. is a large institution with an enrollment of 8,000, a faculty of 950, and a total teaching staff of 1,700. Of its operating expenses by far the largest source of funds in recent years has been sponsored…

  3. Mobile-IT Education (MIT.EDU): M-Learning Applications for Classroom Settings

    ERIC Educational Resources Information Center

    Sung, M.; Gips, J.; Eagle, N.; Madan, A.; Caneel, R.; DeVaul, R.; Bonsen, J.; Pentland, A.

    2005-01-01

    In this paper, we describe the Mobile-IT Education (MIT.EDU) system, which demonstrates the potential of using a distributed mobile device architecture for rapid prototyping of wireless mobile multi-user applications for use in classroom settings. MIT.EDU is a stable, accessible system that combines inexpensive, commodity hardware, a flexible…

  4. Assessing International Product Design and Development Graduate Courses: The MIT-Portugal Program

    ERIC Educational Resources Information Center

    Dori, Yehudit Judy; Silva, Arlindo

    2010-01-01

    The Product Design and Development (PDD) course is part of the graduate curriculum in the Engineering Design and Advanced Manufacturing (EDAM) study in the MIT-Portugal Program. The research participants included about 110 students from MIT, EDAM, and two universities in Portugal, Instituto Superior Técnico-Universidade Técnica de Lisboa (IST) and…

  5. Scratch that: MIT's Mitchel Resnick Says Kids Should Do It for Themselves

    ERIC Educational Resources Information Center

    Traylor, Scott

    2008-01-01

    Mitchel Resnick is a researcher, inventor, and professor at MIT's Media Laboratory in Cambridge, MA, and the founder of the Lifelong Kindergarten Group at MIT. He is the lead innovator behind many cutting-edge learning technologies and projects for children, including the Computer Clubhouse, PicoCrickets, and the wildly successful consumer…

  6. Wilhelm Julius Foerster und die "Vereinigung von Freunden der Astronomie und kosmischen Physik" (1891 bis 1914).

    NASA Astrophysics Data System (ADS)

    Tiemann, K.-H.

    Am 19. Mai 1891 wurde ins Leben gerufen die "Vereinigung von Freunden der Astronomie und der kosmischen Physik (nachfolg.: V.A.P.) - eine der beiden institutionellen Vorläufer der sich 1953 konstituierenden "Vereinigung der Sternfreunde".

  7. "Der Bleistift roch nach Rosmarin": the art of foraging in Stifter, Handke, and Beuys.

    PubMed

    Brady, Martin

    2012-01-01

    Taking as its starting point the notion of ‘reading’ as ‘gathering’, implied by the word Lesen, this essay examines some correspondences between foraging, naming, writing, drawing, and reading to establish a clear distinction between foraging and collecting more generally. By way of example, three kinds of foraging are addressed: berry picking, in Adalbert Stifter's short story Der Waldsteig; mushroom collecting, in Peter Handke's fairy-tale Lucie im Wald mit den Dingsda; gathering medicinal herbs, in particular rosemary, in the drawings, performances, and social sculptures of Joseph Beuys (including Manresa, Barraque D’dull Odde, Geruchsplastik, Blitzschlag mit Lichtschein auf Hirsch). In the literary and visual works discussed here, foraging and its products are therapeutic both physically and spiritually, what Handke terms ‘traumerweiternd’. Moreover, in the case of Beuys in particular this healing process has explicitly social and political implications. The essay also examines foraging as an analogy for the construction of meaning and concludes with a discussion of the clearing as a privileged space in which foraging and gathering, both literally and figuratively, can take place. PMID:22375299

  8. Temperature-driven and photo-induced MIT behaviors of VO2 nanowires

    NASA Astrophysics Data System (ADS)

    Sohn, Ahrum; Kim, Dong-Wook; Byun, Ji-Won; Baik, Jeong Min

    2014-03-01

    VO2 shows a metal-insulator transition (MIT) and structural phase transition (SPT) at critical temperature (Tc) of 343K. It has been known that the MIT and SPT behaviors of VO2 can be tuned by external stimuli such as light, electric-field, and strain. We carried out comparative studies of MIT behaviors of VO2 nanowires during heating-cooling cycles with and without illumination using several light sources (red, blue, and UV). Light can induce change in Tc and hysteresis width of the resistance change. We have investigated influences of light on SPT during MIT. In this presentation, we will discuss possible physical origins for the photo-induced effects on the MIT behaviors of the VO2 nanowires.

  9. Child Care is Everybody's Baby: A Comprehensive Report of Child Care Services, Past, Present, and Future at M.I.T. Final Child Care Proposals as Accepted by M.I.T.

    ERIC Educational Resources Information Center

    Swartz, Marilyn S.

    The report on child care services at M.I.T. explores the following areas: (1) Planning Issues: Why Should M.I.T. Be Involved in Child Care?--educational concerns, services, benefits and costs, priorities, resource allocation; (2) Background for Planning; Current Institute Child Care Programs--a concise history, M.I.T. summer day camp, the…

  10. MIT-KSC space life sciences telescience testbed

    NASA Technical Reports Server (NTRS)

    1989-01-01

    A Telescience Life Sciences Testbed is being developed. The first phase of this effort consisted of defining the experiments to be performed, investigating the various possible means of communication between KSC and MIT, and developing software and hardware support. The experiments chosen were two vestibular sled experiments: a study of ocular torsion produced by Y axis linear acceleration, based on the Spacelab D-1 072 Vestibular Experiment performed pre- and post-flight at KSC; and an optokinetic nystagmus (OKN)/linear acceleration interaction experiment. These two experiments were meant to simulate actual experiments that might be performed on the Space Station and to be representative of space life sciences experiments in general in their use of crew time and communications resources.

  11. Energy Flow in the Magnetosphere-Ionosphere-Thermosphere (MIT) System

    NASA Astrophysics Data System (ADS)

    Huang, C. Y.; Huang, Y.; Su, Y. J.; Sutton, E. K.; Hairston, M. R.

    2015-12-01

    The conventional model of energy input and dissipation in the IT system assumes that the auroral zone is the primary locus for these processes. Recent work has revealed that, contrary to this traditional view, the polar cap can play a significant role in energy transfer during magnetic storms. DMSP measurements of DC Poynting flux shows high levels of electromagnetic energy entering the polar cap at all local times (LTs) in both hemispheres during storms. An analysis of ion temperature observations at DMSP altitudes shows that the largest temperature increases occur at polar latitudes during magnetic activity. Finally, observations of neutral densities from the CHAMP, GRACE and GOCE spacecraft show that the highest frequency of occurrence of heated neutrals occurs close to the poles in both hemispheres. These results demand a revision of the standard paradigm for MIT coupling.

  12. [R]MIT Research Centre at Delft University of Technology: A Bridge between Research, Education, Society and Profession

    ERIC Educational Resources Information Center

    Zijlstra, Hielkje

    2009-01-01

    In 2006, we launched the [R]MIT Research Centre (Modification, Intervention Transformation) at the Faculty of Architecture at Delft University of Technology. [R]MIT was founded to respond to the need for an integrated, multi-disciplinary approach to the transformation of the built environment. [R]MIT aims to bring momentum to the renewal of…

  13. 2mit, an Intronic Gene of Drosophila melanogaster timeless2, Is Involved in Behavioral Plasticity

    PubMed Central

    Benna, Clara; Leonardi, Emanuela; Romoli, Ottavia; Cognolato, Moira; Tosatto, Silvio C. E.; Costa, Rodolfo; Sandrelli, Federica

    2013-01-01

    Background Intronic genes represent ~6% of the total gene complement in Drosophila melanogaster and ~85% of them encode for proteins. We recently characterized the D. melanogaster timeless2 (tim2) gene, showing its active involvement in chromosomal stability and light synchronization of the adult circadian clock. The protein coding gene named 2mit maps on the 11th tim2 intron in the opposite transcriptional orientation. Methodology/Principal Findings Here we report the molecular and functional characterization of 2mit. The 2mit gene is expressed throughout Drosophila development, localizing mainly in the nervous system during embryogenesis and mostly in the mushroom bodies and ellipsoid body of the central complex in the adult brain. In silico analyses revealed that 2mit encodes a putative leucine-Rich Repeat transmembrane receptor with intrinsically disordered regions, harboring several fully conserved functional interaction motifs in the cytosolic side. Using insertional mutations, tissue-specific over-expression, and down-regulation approaches, it was found that 2mit is implicated in adult short-term memory, assessed by a courtship conditioning assay. In D. melanogaster, tim2 and 2mit do not seem to be functionally related. Bioinformatic analyses identified 2MIT orthologs in 21 Drosophilidae, 4 Lepidoptera and in Apis mellifera. In addition, the tim2-2mit host-nested gene organization was shown to be present in A. mellifera and maintained among Drosophila species. Within the Drosophilidae 2mit-hosting tim2 intron, in silico approaches detected a neuronal specific transcriptional binding site which might have contributed to preserve the specific host-nested gene association across Drosophila species. Conclusions/Significance Taken together, these results indicate that 2mit, a gene mainly expressed in the nervous system, has a role in the behavioral plasticity of the adult Drosophila. The presence of a putative 2mit regulatory enhancer within the 2mit-hosting tim2

  14. IntegraTUM Teilprojekt E-Mail: Aufbau eines mandantenfähigen Groupware-Services und seine Integration in Identity Management und E-Mail Infrastruktur der Technischen Universität München

    NASA Astrophysics Data System (ADS)

    Diehn, Max

    Die E-Mail-Infrastruktur an der Technischen Universität München (TUM) ist historisch bedingt sehr heterogen und komplex. Viele Einrichtungen müssen wertvolle Arbeitskraft auf die Administration eigener Mailserver verwenden. Auf der anderen Seite wird bei einigen Einrichtungen der Ruf nach Groupware-Funktionalitäten wie z.B. gemeinsame Kalender immer lauter. Das Teilprojekt E-Mail stellt einen zentralen Mail- und Groupware-Service bereit, der den Einrichtungen ermöglichen soll, den Betrieb eigener Server und zugehöriger Systeme (etwa lokaler Benutzerverwaltungen) für diesen Zweck aufzugeben und diese Dienste an das Teilprojekt E-Mail zu migrieren, ohne ihre Verwaltungshoheit oder ihre Maildomains aufgeben zu müssen. Dieser Service versteht sich als eine Ergänzung zur bestehenden Grundversorgung der TUM mit den Maildiensten des myTUM-Mailers, ist mandantenfähig aufgebaut und kann daher künftig neben der TUM auch weiteren Organisationen im Münchner Wissenschaftsnetz zur Verfügung gestellt werden.

  15. 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.

  16. Qualitätsmanagement in der Lebensmittelindustrie

    NASA Astrophysics Data System (ADS)

    Thorn, Volker

    Die wesentlichen Kunden der Lebensmittelindustrie sind der Einzel- und Großhandel und die Verbraucher. Jedes Unternehmen kann mittel- und langfristig nur existieren, wenn seine Kunden zufrieden sind. Kunden sind zufrieden, wenn ihre Erwartungen, die sie an Produkt, Service und Preis stellen, erfüllt werden. Also die bestimmte erwartete Qualität (Leistung) sichergestellt wird. Trotz aller Bemühungen und Anstrengungen der Anbieter, Qualitätsprodukte auf den Markt zu bringen, kames in den letzten Jahren immer wieder zu Lebensmittelskandalen.

  17. Werner Heisenberg zum 100. Geburtstag: Pionier der Quantenmechanik

    NASA Astrophysics Data System (ADS)

    Jacobi, Manfred

    2001-11-01

    Werner Heisenberg war eine der prägendsten Gestalten der Physik des 20. Jahrhunderts. Zu seinen wichtigsten Verdiensten gehören die Grundlegung der Quantenmechanik, die Formulierung der Unschärferelationen sowie die Beteiligung an der Ausarbeitung der Kopenhagener Deutung der Quantenmechanik. Darüber hinaus lieferte er Arbeiten von fundamentalem Charakter zur Theorie des Atomkerns, zur kosmischen Strahlung und zur Quantenfeldtheorie. Während des Krieges war er an den Arbeiten des Uranvereins beteiligt, der die Möglichkeit einer Entwicklung von Kernwaffen untersuchte, jedoch über Vorarbeiten zur Reaktorphysik nicht hinauskam. Wegen dieser Tätigkeit wurde er bei Kriegsende für einige Monate in England interniert. Nach seiner Rückkehr widmete er sich vor allem dem Aufbau der Physik in Deutschland, die während der NS-Zeit nahezu ihrer gesamten Substanz beraubt worden war.

  18. Having Fun with Physics at the MIT Plasma Science and Fusion Center

    NASA Astrophysics Data System (ADS)

    Rivenberg, P.; Thomas, P.; Censabella, V.; Granville, J.; Nachtrieb, R.; Gangadhara, S.

    1997-11-01

    MIT Plasma Science and Fusion Center staff and students are convinced that students learn best not by studying but by doing. This was the impetus behind a group of MIT graduate students who created Cambridge Physics Outlet, a PSFC spin-off company dedicated to creating hands-on experiments. The same impulse fostered the award-winning Mr. Magnet Program, a traveling presentation which uses a hands-on strategy to engage elementary school children. A number of ingenious experiments will be demonstrated. The PSFC maintains a Home Page on the World Wide Web, which can be reached at HTTP://PFC.MIT.EDU.

  19. 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 ...

  20. Vertebrate MitBASE: a specialised database on vertebrate mitochondrial DNA sequences.

    PubMed

    Carone, A; Malladi, S B; Attimonelli, M; Saccone, C

    1999-01-01

    Vertebrate MitBASE is a specialized database where all the vertebrate mitochondrial DNA entries from primary databases are collected, revised and integrated with new information emerging from the literature. Variant sequences are also analyzed, aligned and linked to reference sequences. Data related to the same species and fragment can be viewed over the WWW. The database has a flexible interface and a retrieval system to help non-expert users and contains information not currently available in the primary databases. Vertebrate MitBASE is now available through the MitBASE home page at URL: http://www.ebi.ac.uk/htbin/Mitbase/mitb ase.pl. This work is part of a larger project, MitBASE which is a network of databases covering the full panorama of knowledge on mitochondrial DNA from protists to human sequences.

  1. MIT Study Sees Nuclear Power as Green Weapon Against Global Warming

    NASA Astrophysics Data System (ADS)

    Dawson, Jim

    2003-12-01

    Although the public doesn't yet view nuclear power as a way to mitigate global warming, an MIT study says a global tripling of nuclear power generation could avoid nearly 2 billion tonnes of carbon emissions annually.

  2. Lessons learned from the MIT Tara control and data system

    SciTech Connect

    Gaudreau, M.P.J.; Sullivan, J.D.; Fredian, T.W.; Irby, J.H.; Karcher, C.A.; Rameriz, R.A.; Sevillano, E.; Stillerman, J.A.; Thomas, P.

    1987-10-01

    The control and data system of the MIT Tara Tandem Mirror has worked successfully throughout the lifetime of the experiment (1983 through 1987). As the Tara project winds down, it is appropriate to summarize the lessons learned from the implementation and operation of the control and data system over the years and in its final form. The control system handled approx.2400 I/0 points in real time throughout the 5 to 10 minute shot cycle while the data system, in near real time, handled approx.1000 signals with a total of 5 to 7 Mbytes of data each shot. The implementation depended upon a consistent approach based on separating physics and engineering functions and on detailed functional diagrams with narrowly defined cross communication. This paper is a comprehensive treatment of the principal successes, residual problems, and dilemmas that arose from the beginning until the final hardware and software implementation. Suggestions for future systems of either similar size or of larger scale such as CIT are made in the conclusion. 11 refs., 1 fig.

  3. Educational Outreach at the MIT Plasma Science and Fusion Center

    NASA Astrophysics Data System (ADS)

    Rivenberg, Paul; Thomas, Paul

    2006-10-01

    At the MIT PSFC, student and staff volunteers work together to increase the public's knowledge of fusion science and plasma technology. Seeking to generate excitement in young people about science and engineering, the PSFC hosts a number of educational outreach activities throughout the year, including Middle and High School Outreach Days. The PSFC also has an in-school science demonstration program on the theme of magnetism. The Mr. Magnet Program, headed by Mr. Paul Thomas, has been bringing lively demonstrations on magnetism into local elementary and middle schools for 15 years. This year Mr. Magnet presented the program to nearly 30,000 students at over 67 schools and other events, reaching kindergartners through college freshmen. In addition to his program on magnetism, he is offering an interactive lecture about plasma to high schools. The "Traveling Plasma Lab" encourages students to learn more about plasma science while having fun investigating plasma properties using actual laboratory techniques and equipment. Beyond the classroom, Paul Thomas has provided technical training for Boston Museum of Science staff in preparation for the opening of a Star Wars exhibit. His hands-on demos have also been filmed by the History Channel for a one-hour program about Magnetism, which aired in June 2006.

  4. Research and Demonstration Program of Day Care Services for M.I.T. Employees. Interim Report.

    ERIC Educational Resources Information Center

    Arterton, Janet Bond

    A survey of day care needs of M.I.T. employees, its resulting information, and a description of the pilot program of day care services undertaken by M.I.T. are included in this report. A survey was administered to all 4,650 Institute employees in April, 1970, and enjoyed a 35% rate of response. The compiled data supports the conclusion that a…

  5. Boer-Mulders function of the pion in the MIT bag model

    NASA Astrophysics Data System (ADS)

    Lu, Zhun; Ma, Bo-Qiang; Zhu, Jiacai

    2012-11-01

    We apply the MIT bag model to study the Boer-Mulders function of the pion, a T-odd function that describes the transverse polarization distribution of the quark inside the pion. We simulate the effect of the gauge link through the “one-gluon-exchange” approximation. We consider both the quark helicity nonflip and double-flip contributions. The result in the MIT bag model is compared with those in the spectator models.

  6. Benchmarking on Tsunami Currents with ComMIT

    NASA Astrophysics Data System (ADS)

    Sharghi vand, N.; Kanoglu, U.

    2015-12-01

    There were no standards for the validation and verification of tsunami numerical models before 2004 Indian Ocean tsunami. Even, number of numerical models has been used for inundation mapping effort, evaluation of critical structures, etc. without validation and verification. After 2004, NOAA Center for Tsunami Research (NCTR) established standards for the validation and verification of tsunami numerical models (Synolakis et al. 2008 Pure Appl. Geophys. 165, 2197-2228), which will be used evaluation of critical structures such as nuclear power plants against tsunami attack. NCTR presented analytical, experimental and field benchmark problems aimed to estimate maximum runup and accepted widely by the community. Recently, benchmark problems were suggested by the US National Tsunami Hazard Mitigation Program Mapping & Modeling Benchmarking Workshop: Tsunami Currents on February 9-10, 2015 at Portland, Oregon, USA (http://nws.weather.gov/nthmp/index.html). These benchmark problems concentrated toward validation and verification of tsunami numerical models on tsunami currents. Three of the benchmark problems were: current measurement of the Japan 2011 tsunami in Hilo Harbor, Hawaii, USA and in Tauranga Harbor, New Zealand, and single long-period wave propagating onto a small-scale experimental model of the town of Seaside, Oregon, USA. These benchmark problems were implemented in the Community Modeling Interface for Tsunamis (ComMIT) (Titov et al. 2011 Pure Appl. Geophys. 168, 2121-2131), which is a user-friendly interface to the validated and verified Method of Splitting Tsunami (MOST) (Titov and Synolakis 1995 J. Waterw. Port Coastal Ocean Eng. 121, 308-316) model and is developed by NCTR. The modeling results are compared with the required benchmark data, providing good agreements and results are discussed. Acknowledgment: The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant

  7. 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.

  8. Knocking down mitochondrial iron transporter (MIT) reprograms primary and secondary metabolism in rice plants.

    PubMed

    Vigani, Gianpiero; Bashir, Khurram; Ishimaru, Yasuhiro; Lehmann, Martin; Casiraghi, Fabio Marco; Nakanishi, Hiromi; Seki, Motoaki; Geigenberger, Peter; Zocchi, Graziano; Nishizawa, Naoko K

    2016-03-01

    Iron (Fe) is an essential micronutrient for plant growth and development, and its reduced bioavailability strongly impairs mitochondrial functionality. In this work, the metabolic adjustment in the rice (Oryza sativa) mitochondrial Fe transporter knockdown mutant (mit-2) was analysed. Biochemical characterization of purified mitochondria from rice roots showed alteration in the respiratory chain of mit-2 compared with wild-type (WT) plants. In particular, proteins belonging to the type II alternative NAD(P)H dehydrogenases accumulated strongly in mit-2 plants, indicating that alternative pathways were activated to keep the respiratory chain working. Additionally, large-scale changes in the transcriptome and metabolome were observed in mit-2 rice plants. In particular, a strong alteration (up-/down-regulation) in the expression of genes encoding enzymes of both primary and secondary metabolism was found in mutant plants. This was reflected by changes in the metabolic profiles in both roots and shoots of mit-2 plants. Significant alterations in the levels of amino acids belonging to the aspartic acid-related pathways (aspartic acid, lysine, and threonine in roots, and aspartic acid and ornithine in shoots) were found that are strictly connected to the Krebs cycle. Furthermore, some metabolites (e.g. pyruvic acid, fumaric acid, ornithine, and oligosaccharides of the raffinose family) accumulated only in the shoot of mit-2 plants, indicating possible hypoxic responses. These findings suggest that the induction of local Fe deficiency in the mitochondrial compartment of mit-2 plants differentially affects the transcript as well as the metabolic profiles in root and shoot tissues. PMID:26685186

  9. 76 FR 31230 - Safety Zone; M.I.T.'s 150th Birthday Celebration Fireworks, Charles River, Boston, MA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-31

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; M.I.T.'s 150th Birthday Celebration...) Zone for the M.I.T.'s 150th Birthday Celebration Fireworks display. This safety zone is necessary to.... 165.T01-0375 to read as follows: Sec. 165.T01-0375 Safety Zone; M.I.T.'s 150th Birthday...

  10. Kommunikationsanforderungen an verteilte Echtzeitsysteme in der Fertigungsautomatisierung

    NASA Astrophysics Data System (ADS)

    Just, Roman; Trsek, Henning

    Kommunikationssysteme der Automatisierung müssen hohe zeitliche Anforderungen erfüllen, damit die entsprechenden industriellen Anwendungen realisiert werden können. Im Gegensatz zum IT-Bereich sind diese Anforderungen jedoch häufig nicht genau bekannt, was insbesondere beim Einsatz von drahtlosen Technologien Probleme bereiten kann1. In dieser Arbeit werden Verkehrsmuster einer realen Anlage aus dem Bereich der Fertigungsautomatisierung bestimmt. Die Zwischenankunfts- und Latenzzeiten einzelner Sensorund Aktorsignale ermöglichen Rückschlüsse auf zeitliche Anforderungen und Charakteristiken der untersuchten Anwendung. Im Anschluss werden die erzielten Erkenntnisse hinsichtlich ausgewählter Kommunikationsanforderungen analysiert und aktuell gültige Anforderungen von realen Automatisierungsanlagen abgeleitet. Weiterhin werden sie zukünftig zur Entwicklung realitätsnaher Simulationsmodelle genutzt.

  11. Mit1 Transcription Factor Mediates Methanol Signaling and Regulates the Alcohol Oxidase 1 (AOX1) Promoter in Pichia pastoris.

    PubMed

    Wang, Xiaolong; Wang, Qi; Wang, Jinjia; Bai, Peng; Shi, Lei; Shen, Wei; Zhou, Mian; Zhou, Xiangshan; Zhang, Yuanxing; Cai, Menghao

    2016-03-18

    The alcohol oxidase 1 (AOX1) promoter (P AOX1) of Pichia pastoris is the most powerful and commonly used promoter for driving protein expression. However, mechanisms regulating its transcriptional activity are unclear. Here, we identified a Zn(II)2Cys6-type methanol-induced transcription factor 1 (Mit1) and elucidated its roles in regulating PAOX1 activity in response to glycerol and methanol. Mit1 regulated the expression of many genes involved in methanol utilization pathway, including AOX1, but did not participate in peroxisome proliferation and transportation of peroxisomal proteins during methanol metabolism. Structural analysis of Mit1 by performing domain deletions confirmed its specific and critical role in the strict repression of P AOX1 in glycerol medium. Importantly, Mit1, Mxr1, and Prm1, which positively regulated P AOX1 in response to methanol, were bound to P AOX1 at different sites and did not interact with each other. However, these factors cooperatively activated P AOX1 through a cascade. Mxr1 mainly functioned during carbon derepression, whereas Mit1 and Prm1 functioned during methanol induction, with Prm1 transmitting methanol signal to Mit1 by binding to the MIT1 promoter (P MIT1), thus increasingly expressing Mit1 and subsequently activating P AOX1.

  12. MIT Clean Energy Prize: Final Technical Report May 12, 2010 - May 11, 2011

    SciTech Connect

    Snyder, Chris; Campbell, Georgina; Salony, Jason; Aulet, Bill

    2011-08-09

    The MIT Clean Energy Prize (MIT CEP) is a venture creation and innovation competition to encourage innovation in the energy space, specifically with regard to clean energy. The Competition invited student teams from any US university to submit student-led ventures that demonstrate a high potential of successfully making clean energy more affordable, with a positive impact on the environment. By focusing on student ventures, the MIT CEP aims to educate the next generation of clean energy entrepreneurs. Teams receive valuable mentoring and hard deadlines that complement the cash prize to accelerate development of ventures. The competition is a year-long educational process that culminates in the selection of five category finalists and a Grand Prize winner and the distribution of cash prizes to each of those teams. Each entry was submitted in one of five clean energy categories: Renewables, Clean Non-Renewables, Energy Efficiency, Transportation, and Deployment.

  13. A New Tool for Inundation Modeling: Community Modeling Interface for Tsunamis (ComMIT)

    NASA Astrophysics Data System (ADS)

    Titov, V. V.; Moore, C. W.; Greenslade, D. J. M.; Pattiaratchi, C.; Badal, R.; Synolakis, C. E.; Kânoğlu, U.

    2011-11-01

    Almost 5 years after the 26 December 2004 Indian Ocean tragedy, the 10 August 2009 Andaman tsunami demonstrated that accurate forecasting is possible using the tsunami community modeling tool Community Model Interface for Tsunamis (ComMIT). ComMIT is designed for ease of use, and allows dissemination of results to the community while addressing concerns associated with proprietary issues of bathymetry and topography. It uses initial conditions from a precomputed propagation database, has an easy-to-interpret graphical interface, and requires only portable hardware. ComMIT was initially developed for Indian Ocean countries with support from the United Nations Educational, Scientific, and Cultural Organization (UNESCO), the United States Agency for International Development (USAID), and the National Oceanic and Atmospheric Administration (NOAA). To date, more than 60 scientists from 17 countries in the Indian Ocean have been trained and are using it in operational inundation mapping.

  14. MITR-III: Upgrade and relicensing studies for the MIT Research Reactor. Second annual report

    SciTech Connect

    Trosman, H.G.; Lanning, D.D.; Harling, O.K.

    1994-08-01

    The current operating license of the MIT research reactor will expire on May 7, 1996 or possibly a few years later if the US Nuclear Regulatory Commission agrees that the license period can start with the date of initial reactor operation. Driven by the imminent expiration of the operating license, a team of nuclear engineering staff and students have begun a study of the future options for the MIT Research Reactor. These options have included the range from a major rebuilding of the reactor to its decommissioning. This document reports the results of a two year intensive activity which has been supported by a $148,000 grant from the USDOE contract Number DEFG0293ER75859, approximately $100,000 of internal MIT funds and Nuclear Engineering Department graduate student fellowships as well as assistance from international visiting scientists and engineers.

  15. Fusion Science Outreach at the MIT Plasma Science and Fusion Center

    NASA Astrophysics Data System (ADS)

    Censabella, V.; Rivenberg, P.; Granville, J.; Nachtrieb, R.; Gangadhara, S.

    1997-11-01

    Educational Outreach at the MIT Plasma Science and Fusion Center is organized and energized by volunteers working together to increase the public's knowledge of fusion and plasma-related experiments. The PSFC holds a number of outreach activities throughout the year, such as Middle and High School Outreach Days. Included in these days is a demonstration of how magnets affect plasma using the ``Plasma Demo," an educational tool which will be on display for the first time outside the MIT area. Also featured is ``C-Mod Jr.," a video game which helps students discover how computers manipulate magnetic pulses to keep a plasma confined in the C-Mod tokamak for as long as possible. The PSFC maintains a Home Page on the World Wide Web, which can be reached at HTTP://PFC.MIT.EDU.

  16. Darwin, Engels und die Rolle der Arbeit in der biologischen und kulturellen Evolution des Menschen

    NASA Astrophysics Data System (ADS)

    Reichholf, Josef H.

    Im Jahre 1876, 5 Jahre nach Erscheinen von Darwins Buch über die Evolution des Menschen und die sexuelle Selektion (Darwin 1871), veröffentlichte Friedrich Engels den berühmt gewordenen Essay "Anteil der Arbeit an der Menschwerdung des Affen“ (Engels 1876). Die Kernfrage darin lautet in Kurzform: Warum hat der Mensch eigentlich ein Bedürfnis nach Arbeit? Engels Antwort wird nachfolgend näher betrachtet und vom gegenwärtigen Kenntnisstand aus beurteilt. Wie sich zeigen wird, beantworten seine Überlegungen die Frage nicht wirklich. Sie ist weiterhin offen. Es können lediglich einige zusätzliche Anhaltspunkte zur Diskussion gestellt werden. Angesichts des drängenden Problems millionenfacher Arbeitslosigkeit und der Forderungen nach einem "Grundrecht auf Arbeit“ kommt den Überlegungen zum möglichen Ursprung des Bedürfnisses nach Arbeit mehr als nur akademisches Interesse zu.

  17. 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.

  18. Auf der Suche nach extrasolaren Transitplaneten

    NASA Astrophysics Data System (ADS)

    Heller, René

    2010-06-01

    Planeten um andere Sonnen, die von der Erde aus gesehen einmal während ihres Orbits vor ihrem Zentralstern vorbeiziehen, eröffnen eine bis vor Kurzem ungeahnte Palette an Möglichkeiten zu ihrer Untersuchung. Nur: Wo am Himmel lassen sich diese Kandidaten für Sternbedeckungen eigentlich finden?

  19. 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)

  20. 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,…

  1. 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...

  2. Center for Multiscale Plasma Dynamics: Report on Activities (UCLA/MIT), 2009-2010

    SciTech Connect

    Troy Carter

    2011-04-18

    The final 'phaseout' year of the CMPD ended July 2010; a no cost extension was requested until May 2011 in order to enable the MIT subcontract funds to be fully utilized. Research progress over this time included verification and validation activities for the BOUT and BOUT++ code, studies of spontaneous reconnection in the VTF facility at MIT, and studies of the interaction between Alfven waves and drift waves in LAPD. The CMPD also hosted the 6th plasma physics winter school in 2010 (jointly with the NSF frontier center the Center for Magnetic Self-Organization, significant funding came from NSF for this most recent iteration of the Winter School).

  3. Chirurgische Behandlung von Melanomen in der Schwangerschaft: eine praktische Anleitung.

    PubMed

    Crisan, Diana; Treiber, Nicolai; Kull, Thomas; Widschwendter, Peter; Adolph, Oliver; Schneider, Lars Alexander

    2016-06-01

    Als ein Tumor, der primär eine chirurgische Behandlung erfordert, ist ein neu diagnostiziertes oder vorbestehendes Melanom in der Schwangerschaft eine klinische Rarität. In solchen Fällen steht der Chirurg vor der Herausforderung, ein geeignetes therapeutisches Vorgehen festlegen zu müssen. Auf der Grundlage unserer klinischen Erfahrung und einer Übersicht über die Literatur geben wir in der vorliegenden Arbeit eine Anleitung für das praktische Vorgehen bei dieser seltenen klinischen Konstellation. Unserer Erfahrung nach müssen schwangere Melanom-Patientinnen im Hinblick auf ihre therapeutischen Optionen ausführlich beraten werden. Naturgemäß setzen sie ihr ungeborenes Kind an die erste Stelle und zögern, der erforderlichen Operation zuzustimmen, obwohl bei ihnen eine möglicherweise lebensbedrohliche Erkrankung diagnostiziert worden ist. Daher ist es entscheidend, diese Patientinnen klar darüber zu informieren, dass, wie die vorliegenden medizinischen Erfahrungen zeigen, eine Schwangerschaft per se kein Grund ist, eine notwendige Melanom-Operation aufzuschieben. Jedoch müssen bei einigen Parametern wie den präoperativen Bildgebungsverfahren, der Positionierung auf dem Operationstisch, der Überwachung, Anästhesie und der perioperativen Medikation bestimmte Anpassungen vorgenommen werden, um der speziellen Situation Rechnung zu tragen. PMID:27240063

  4. How Much Have They Retained? Making Unseen Concepts Seen in a Freshman Electromagnetism Course at MIT

    ERIC Educational Resources Information Center

    Dori, Yehudit Judy; Hult, Erin; Breslow, Lori; Belcher, John W.

    2007-01-01

    The introductory freshmen electromagnetism course at MIT has been taught since 2000 using a studio physics format entitled TEAL--Technology Enabled Active Learning. TEAL has created a collaborative, hands-on environment where students carry out desktop experiments, submit web-based assignments, and have access to a host of visualizations and…

  5. Graduate Training and Potential Employment for Political Scientists: The MIT Perspective.

    ERIC Educational Resources Information Center

    Altshuler, Alan

    This paper presents ideas on ways to help graduate students in political science to become more marketable for nonacademic positions. It also includes background information on the changing employment market for Ph.D.'s. These ideas were discussed at a 1980 meeting of teachers, graduate students, and recent Ph.D.'s at MIT. The purpose of the…

  6. Zum Wissenschaftsverständnis der modernen Evolutionsbiologie

    NASA Astrophysics Data System (ADS)

    Sommer, Ralf J.

    Die moderne Evolutionsbiologie hat ihren Ursprung in den Arbeiten von Charles Darwin und Alfred Wallace (Darwin 1963). Der gemeinsame Ausgangspunkt des Evolutionsgedanken ist dabei die Beobachtung, dass die biologische Welt nicht konstant ist. Biologische Systeme und alle darin lebenden Organismen unterliegen über längere Zeiträume hinweg einer stetigen Veränderung. Diese grundlegende Eigenschaft biologischer Systeme macht die Biologie zu einer historischen Wissenschaft und stellt einen wichtigen Gegensatz zu großen Teilen der Physik dar. Obwohl die Aussage von der Veränderlichkeit der Arten heute trivial klingt, war sie im 19. Jahrhundert eine Revolution, da die Konstanz der Arten und der Welt eine vorherrschende Stellung im damaligen Weltbild hatte (Amundson 2005).

  7. Datenqualitäts-Modell der Volkswagen Financial Services AG

    NASA Astrophysics Data System (ADS)

    Moser, Helena

    Im Rahmen der Vertriebsaktivitäten und der umfangreichen rechtlichen und regulatorischen Anforderungen u. a. Basel II hat die Volkswagen Financial Services AG (nachfolgend VW FS AG) beschlossen, dem Thema Datenqualität und Datenqualitätsmanagement, insbesondere unter dem Blickwinkel der Konzern Leitlinien Kundennähe, Schaffung von Werten und Höchstleistung, eine hohe Priorität einzuräumen.

  8. Bereits nach Ablauf der Halbwertszeit droht der vollständige Zerfall Die britische Atomic Scientists’ Association, die Ideologie der „objektiven” Wissenschaft und die H-Bombe

    NASA Astrophysics Data System (ADS)

    Laucht, Christoph

    Präsident Harry Trumans Verlautbarung vom 31.1.1950, seine Regierung wolle die Entwicklung der Wasserstoffbombe vorantreiben, fand große Beachtung in den britischen Medien. Die illustrierte Zeitschrift Picture Post widmete der HBombe einen Artikel, der unter anderem kurze Stellungnahmen der britischen Atomwissenschaftler Eric Burhop, Kathleen Lonsdale, Harrie Massey, Rudolf Peierls und Maurice Pryce enthielt, die alle Mitglieder der Atomic Scientists' Association (ASA) waren.

  9. Information Interaction Study for DER and DMS Interoperability

    NASA Astrophysics Data System (ADS)

    Liu, Haitao; Lu, Yiming; Lv, Guangxian; Liu, Peng; Chen, Yu; Zhang, Xinhui

    The Common Information Model (CIM) is an abstract data model that can be used to represent the major objects in Distribution Management System (DMS) applications. Because the Common Information Model (CIM) doesn't modeling the Distributed Energy Resources (DERs), it can't meet the requirements of DER operation and management for Distribution Management System (DMS) advanced applications. Modeling of DER were studied based on a system point of view, the article initially proposed a CIM extended information model. By analysis the basic structure of the message interaction between DMS and DER, a bidirectional messaging mapping method based on data exchange was proposed.

  10. Nanomedical strategy to prolong survival period, heighten cure rate, and lower systemic toxicity of S180 mice treated with MTX/MIT

    PubMed Central

    Song, Ning; Zhao, Ming; Wang, Yuji; Hu, Xi; Wu, Jianhui; Jiang, Xueyun; Li, Shan; Cui, Chunying; Peng, Shiqi

    2016-01-01

    In spite of the usual combination form of methotrexate (MTX)/mitoxantrone (MIT) and various complex combination regimens of MTX/MIT with other anticancer drugs, the survival period, cure rate, and systemic toxicity still need to be improved. For this purpose, a nanostructured amino group-modified mesoporous silica nanoparticles (MSNN)−MTX/MIT was designed. In the preparation, the surface of mesoporous silica nanoparticles (MSNs) was modified with amino groups to form MSNN. The covalent modification of the amino groups on the surface of MSNN with MTX resulted in MSNN−MTX. The loading of MIT into the surface pores of MSNN−MTX produced nanostructured MSNN−MTX/MIT. Compared with the usual combination form (MTX/MIT), nanostructured MSNN−MTX/MIT increased the survival period greatly, heightened the cure rate to a great extent, and lowered the systemic toxicity of the treated S180 mice, significantly. These superior in vivo properties of nanostructured MSNN−MTX/MIT over the usual combination form (MTX/MIT) were correlated with the former selectively releasing MTX and MIT in tumor tissue and inside cancer cells in vitro. The chemical structure and the nanostructure of MSNN−MTX/MIT were characterized using infrared and differential scanning calorimeter spectra as well as transmission electron microscope images, respectively. PMID:27621591

  11. Nanomedical strategy to prolong survival period, heighten cure rate, and lower systemic toxicity of S180 mice treated with MTX/MIT

    PubMed Central

    Song, Ning; Zhao, Ming; Wang, Yuji; Hu, Xi; Wu, Jianhui; Jiang, Xueyun; Li, Shan; Cui, Chunying; Peng, Shiqi

    2016-01-01

    In spite of the usual combination form of methotrexate (MTX)/mitoxantrone (MIT) and various complex combination regimens of MTX/MIT with other anticancer drugs, the survival period, cure rate, and systemic toxicity still need to be improved. For this purpose, a nanostructured amino group-modified mesoporous silica nanoparticles (MSNN)−MTX/MIT was designed. In the preparation, the surface of mesoporous silica nanoparticles (MSNs) was modified with amino groups to form MSNN. The covalent modification of the amino groups on the surface of MSNN with MTX resulted in MSNN−MTX. The loading of MIT into the surface pores of MSNN−MTX produced nanostructured MSNN−MTX/MIT. Compared with the usual combination form (MTX/MIT), nanostructured MSNN−MTX/MIT increased the survival period greatly, heightened the cure rate to a great extent, and lowered the systemic toxicity of the treated S180 mice, significantly. These superior in vivo properties of nanostructured MSNN−MTX/MIT over the usual combination form (MTX/MIT) were correlated with the former selectively releasing MTX and MIT in tumor tissue and inside cancer cells in vitro. The chemical structure and the nanostructure of MSNN−MTX/MIT were characterized using infrared and differential scanning calorimeter spectra as well as transmission electron microscope images, respectively.

  12. Nanomedical strategy to prolong survival period, heighten cure rate, and lower systemic toxicity of S180 mice treated with MTX/MIT.

    PubMed

    Song, Ning; Zhao, Ming; Wang, Yuji; Hu, Xi; Wu, Jianhui; Jiang, Xueyun; Li, Shan; Cui, Chunying; Peng, Shiqi

    2016-01-01

    In spite of the usual combination form of methotrexate (MTX)/mitoxantrone (MIT) and various complex combination regimens of MTX/MIT with other anticancer drugs, the survival period, cure rate, and systemic toxicity still need to be improved. For this purpose, a nanostructured amino group-modified mesoporous silica nanoparticles (MSNN)-MTX/MIT was designed. In the preparation, the surface of mesoporous silica nanoparticles (MSNs) was modified with amino groups to form MSNN. The covalent modification of the amino groups on the surface of MSNN with MTX resulted in MSNN-MTX. The loading of MIT into the surface pores of MSNN-MTX produced nanostructured MSNN-MTX/MIT. Compared with the usual combination form (MTX/MIT), nanostructured MSNN-MTX/MIT increased the survival period greatly, heightened the cure rate to a great extent, and lowered the systemic toxicity of the treated S180 mice, significantly. These superior in vivo properties of nanostructured MSNN-MTX/MIT over the usual combination form (MTX/MIT) were correlated with the former selectively releasing MTX and MIT in tumor tissue and inside cancer cells in vitro. The chemical structure and the nanostructure of MSNN-MTX/MIT were characterized using infrared and differential scanning calorimeter spectra as well as transmission electron microscope images, respectively. PMID:27621591

  13. The MIT Accelerator Laboratory for Diagnostic Development for OMEGA, Z and the NIF

    NASA Astrophysics Data System (ADS)

    Petrasso, R.; Gatu Johnson, M.; Armstrong, E.; Orozco, D.; Rinderknecht, H. G.; Rojas Herrera, J.; Rosenberg, M.; Sio, H.; Zylstra, A.; Frenje, J.; Li, C. K.; Seguin, F. H.; Hahn, K.; Jones, B.; Ruiz, C. L.; Sangster, T. C.

    2014-10-01

    The MIT Linear Electrostatic Ion Accelerator generates D-D and D-3He fusion products, which are used for development of nuclear diagnostics for OMEGA, Z, and the NIF. Fusion reaction rates around 106 s-1 are routinely achieved with this accelerator, and fluence and energy of the fusion products are accurately characterized. Diagnostics developed and calibrated at this facility include CR-39 based charged-particle spectrometers, neutron detectors, and the particle Time-Of-Flight (pTOF) CVD-diamond-based bang time detector. The accelerator is also a vital tool in the education of graduate and undergraduate students at MIT. This work was supported in part by SNL, DOE, LLE and LLNL.

  14. Educational Outreach at the M.I.T. Plasma Fusion Center

    NASA Astrophysics Data System (ADS)

    Censabella, V.

    1996-11-01

    Educational outreach at the MIT Plasma Fusion Center consists of volunteers working together to increase the public's knowledge of fusion and plasma-related experiments. Seeking to generate excitement about science, engineering and mathematics, the PFC holds a number of outreach activities throughout the year, such as Middle and High School Outreach Days. Outreach also includes the Mr. Magnet Program, which uses an interactive strategy to engage elementary school children. Included in this year's presentation will be a new and improved C-MOD Jr, a confinement video game which helps students to discover how computers manipulate magnetic pulses to keep a plasma confined for as long as possible. Also on display will be an educational toy created by the Cambridge Physics Outlet, a PFC spin-off company. The PFC maintains a Home Page on the World Wide Web, which can be reached at http://cmod2.pfc.mit.edu/.

  15. Die Deutsche Statistische Gesellschaft in der Weimarer Republik und während der Nazidiktatur

    NASA Astrophysics Data System (ADS)

    Wilke, Jürgen

    Nach anfänglichen Schwierigkeiten durch den 1. Weltkrieg erlangte die Deutsche Statistische Gesellschaft (DStatG) unter dem renommierten Statistiker und Vorsitzenden der DStatG, Friedrich Zahn, durch eine Vielzahl von Aktivitäten hohes Ansehen. Es gab Bestrebungen, Statistiker aus allen Arbeitsfeldern der Statistik in die DStatG zu integrieren, wobei die "Mathematische Statistik" nur zögerlich akzeptiert wurde (Konjunkturforschung, Zeitreihenanalyse). Nach der Machtübernahme 1933 durch Adolf Hitler geriet die DStatG in das Fahrwasser nationalsozialistischer Ideologie und Politik (Führerprinzip, Gleichschaltung des Vereinswesens). Damit war eine personelle Umstrukturierung in der DStatG verbunden. Politisch Missliebige und rassisch Verfolgte mussten die DStatG verlassen (Bernstein, Freudenberg, Gumbel u.a.). Unter den Statistikern gab es alle Abstufungen im Verhalten zum Regime von Ablehnung und zwangsweiser Anpassung über bereitwilliges Mitläufertum bis zu bewusster Täterschaft. Besonders die Bevölkerungsstatistik wurde durch die NS- Rassenpolitik auf lange Sicht diskreditiert. Im Rahmen von Wirtschaftsplanung und Aufrüstung wurden neue zukunftsträchtige statistische Modelle (Grünig, Bramstedt, Leisse) entwickelt.

  16. Biological activity of recombinant Der p 2, Der p 5 and Der p 7 allergens of the house-dust mite Dermatophagoides pteronyssinus.

    PubMed

    Lynch, N R; Thomas, W R; Garcia, N M; Di Prisco, M C; Puccio, F A; L'opez, R I; Hazell, L A; Shen, H D; Lin, K L; Chua, K Y

    1997-09-01

    Der p 2, Der p 5 and Der p 7 are three allergens of the house-dust mite Dermatophagoides pteronyssinus that have been cloned and expressed in Escherichia coli as fusion proteins with glutathione-S-transferase (GST). We showed that these recombinant allergens produced immediate hypersensitivity skin-test reactions in 70, 60 and 52% respectively of a group of mite-sensitive allergic patients who were strongly positive to whole mite extract (WME). Comparable positivities were found for serum levels of specific IgE antibody against these allergens, as measured by the radioallergosorbant test (RAST). Overall, for the group of allergic patients that we evaluated, the serum IgE antibody concentrations against Der p 2, 5 and 7 were calculated to represent about one third, one quarter and one fifth respectively of the levels measured against the WME. However, for some patients the activity determined against the separate allergens was far higher than that detected against the WME, thus indicating that the concentration of these can be limiting in the WME. We found no significant correlations between the RAST levels against Derp 2 and either Derp 5 or 7, and RAST-inhibition tests indicated a lack of cross-reactivity between Der p 2 and the other two allergens. In contrast, the RAST results revealed the existence of a significant immunological relationship between Der p 5 and 7. Although a certain degree of reactivity against the GST fusion partner was found in the allergic patients studied, this was not a significant influence in determining the positivity against the recombinant allergens. These results confirm the in vivo biological activity of recombinant Der p 2, 5 and 7, and indicate that whilst Der p 2 is undoubtedly a major mite allergen, both Der p 5 and 7 make important contributions toward the overall allergenic activity of house-dust mites. PMID:9303332

  17. Franz Selety (1893-1933?). His cosmological investigations and the correspondence with Einstein (German Title: Franz Selety (1893-1933?). Seine kosmologischen Arbeiten und der Briefwechsel mit Einstein)

    NASA Astrophysics Data System (ADS)

    Jung, Tobias

    In 1922, Franz Selety, university-bred philosopher and self-educated physicist and cosmologist, developed a molecular hierarchical, spatially infinite, Newtonian cosmological model. His considerations were based on his earlier philosophical work published in 1914 as well as on the early correspondence with Einstein in 1917. Historically, the roots of hierarchical models can be seen in 18th century investigations by Thomas Wright of Durham, Immanuel Kant and Johann Heinrich Lambert. Those investigations were taken up by Edmund Fournier d'Albe and Carl Charlier at the beginning of the 20th century. Selety's cosmological model was criticized by Einstein mainly due to its spatial infiniteness which in Einstein's opinion seemed to contradict Mach's principle. This criticism sheds light on Einstein's conviction that with his first cosmological model, namely the static, spatially infinite, though unbounded Einstein Universe of 1917, the appropriate cosmological theory already had been established.

  18. Die Arbeit mit Schulfernsehsendungen in Abschluss--und Aufbauklassen der Hauptschule (Working with School Television Broadcasts in Terminal and Continuation Grades of the Hauptschule ["Terminal" 9-Grade School])

    ERIC Educational Resources Information Center

    Bebermeier, Hans

    1978-01-01

    Finds school television broadcasting a useful language teaching device, and television films in particular useful for "situational teaching." Various aspects are discussed, including the use of video recorders. (Text is in German.) (IFS/WGA)

  19. der(16)t(1;16)/der(1;16) in breast cancer detected by fluorescence in situ hybridization is an indicator of better patient prognosis.

    PubMed

    Tsuda, H; Takarabe, T; Fukutomi, T; Hirohashi, S

    1999-01-01

    By two-color fluorescence in situ hybridization (FISH), der(16)t(1;16) or der(1;16) was frequently detected in low-grade papillary carcinoma but not in benign intraductal papilloma of the breast. In order to clarify the incidence and clinicopathological significance of der(16)t(1;16)/der(1;16) in common breast cancers, der(16)t(1;16)/der(1;16) was examined by two-color FISH in breast cancers resected from 51 patients by using DNA probes for 16cen, 16q11.2, and 1q12 labeled with biotin or digoxigenin. der(16)t(1;16)/der(1;16) was clonally detected in 16 cancers (31%), being more frequent in ductal carcinomas of lower grade and invasive lobular carcinoma than in high-grade invasive ductal carcinoma (P<0.001). der(16)t(1;16)/der(1;16) was also correlated with a higher amount of hormone receptors in the tumor (P<0.05). Disease-free and overall survival rates of the patient group with der(16)t(1;16)/der(1;16)-positive cancer were higher (88% and 94%) than those of the group with der(16)t(1;16)/der(1; 16)-negative cancer (39% and 68%) (P<0.05). Among the 16 patients with lymph node metastasis who received one of two similar forms of postsurgical adjuvant chemo-endocrine therapy, the prognosis of those with der(16)t(1;16)/der(1;16)-positive cancer was better than that of those with der(16)t(1;16)/der(1;16)-negative cancer (P<0.05). der(16)t(1;16)/der(1;16) detected by FISH is considered helpful in identifying patients with a better prognosis and for stratification of patients in randomized clinical trials of adjuvant chemo-endocrine therapies. PMID:9892111

  20. 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.

  1. The neurosciences research program at MIT and the beginning of the modern field of neuroscience.

    PubMed

    Adelman, George

    2010-01-15

    The interdisciplinary field, "neuroscience," began at MIT in 1962 with the founding of the Neurosciences Research Program (NRP) by Francis O. Schmitt and a group of US and international scientists - physical, biological, medical, and behavioral - interested in understanding the brain basis of behavior and mind. They organized and held specialist meetings of basic topics in neuroscience, and the journal and book publications over the next 20 years, based on these meetings, helped establish the new field.

  2. The MIT high resolution X-ray spectroscopy instruments on AXAF

    NASA Astrophysics Data System (ADS)

    Canizares, C. R.; Dewey, D.; Galton, E. B.; Markert, T. H.; Smith, Henry I.; Schattenburg, M. L.; Woodgate, B. E.; Jordan, S.

    1992-03-01

    The general design and performance characteristics of MIT's two dispersive spectrometers, the Bragg Crystal Spectrometer (BCS) and the High Energy Transmission Grating Spectrometer (HETG), now being developed for the Advanced X-ray Astrophysics Facility (AXAF), are described. Particular attention is given to the development of the critical technologies incorporated into these instruments, including BCS diffractors, imaging gas flow proportional counters, and grating elements for the HETG. The principal stages and the current status of the developments are reviewed.

  3. Teleoperation experiments with a Utah/MIT hand and a VPL DataGlove

    NASA Technical Reports Server (NTRS)

    Clark, D.; Demmel, J.; Hong, J.; Lafferriere, Gerardo; Salkind, L.; Tan, X.

    1989-01-01

    A teleoperation system capable of controlling a Utah/MIT Dextrous Hand using a VPL DataGlove as a master is presented. Additionally the system is capable of running the dextrous hand in robotic (autonomous) mode as new programs are developed. The software and hardware architecture used is presented and the experiments performed are described. The communication and calibration issues involved are analyzed and applications to the analysis and development of automated dextrous manipulations are investigated.

  4. Gaussian frequency blending algorithm with matrix inversion tomosynthesis (MITS) and filtered back projection (FBP) for better digital breast tomosynthesis reconstruction

    NASA Astrophysics Data System (ADS)

    Chen, Ying; Lo, Joseph Y.; Baker, Jay A.; Dobbins, James T., III

    2006-03-01

    Breast cancer is a major problem and the most common cancer among women. The nature of conventional mammpgraphy makes it very difficult to distinguish a cancer from overlying breast tissues. Digital Tomosynthesis refers to a three-dimensional imaging technique that allows reconstruction of an arbitrary set of planes in the breast from limited-angle series of projection images as the x-ray source moves. Several tomosynthesis algorithms have been proposed, including Matrix Inversion Tomosynthesis (MITS) and Filtered Back Projection (FBP) that have been investigated in our lab. MITS shows better high frequency response in removing out-of-plane blur, while FBP shows better low frequency noise propertities. This paper presents an effort to combine MITS and FBP for better breast tomosynthesis reconstruction. A high-pass Gaussian filter was designed and applied to three-slice "slabbing" MITS reconstructions. A low-pass Gaussian filter was designed and applied to the FBP reconstructions. A frequency weighting parameter was studied to blend the high-passed MITS with low-passed FBP frequency components. Four different reconstruction methods were investigated and compared with human subject images: 1) MITS blended with Shift-And-Add (SAA), 2) FBP alone, 3) FBP with applied Hamming and Gaussian Filters, and 4) Gaussian Frequency Blending (GFB) of MITS and FBP. Results showed that, compared with FBP, Gaussian Frequency Blending (GFB) has better performance for high frequency content such as better reconstruction of micro-calcifications and removal of high frequency noise. Compared with MITS, GFB showed more low frequency breast tissue content.

  5. MIT: A Future Mission to Investigate Magnetosphere-Ionosphere-Thermosphere Coupling with Multipoint Observations

    NASA Astrophysics Data System (ADS)

    Liu, Y.

    2015-12-01

    The Magnetosphere, Ionosphere and Thermosphere (MIT) mission is one of the Space Science Strategic Pioneer Projects of the Chinese Academy of Sciences (CAS). Its major scientific objectives focus on the heating, acceleration and transport processes of ions in the polar regions and on their impact on the ring current and radiation belts. Because of the dynamic nature of these processes that also vary with altitude, it is imperative to cover with MIT altitudes from a few 100 km to several earth radii. This will be accomplished with a novel constellation of four spacecraft in polar orbits that provide periodic simultaneous measurements in the polar regions at three different altitudes. The two Ionospheric spacecraft have a polar orbit of 500km*1500km. The other two spacecraft have symmetric polar orbits with geocentric distances of 2Re*8Re (Re is the radius of the Earth).With instrument packages covering particle and field measurements over a wide energy range on all four spacecraft we will be able to monitor and investigate all relevant processes, including ion outflow from the source region in the ionosphere, their acceleration at mid-altitudes, to their final destination in the magnetosphere. Presently, MIT is in the background study stage that will be completed in 2015, with the engineering stage planed to start in 2016, if selected.

  6. MIT: A Future Mission to Investigate Magnetosphere-Ionosphere-Thermosphere Coupling with Multipoint Observations

    NASA Astrophysics Data System (ADS)

    Liu, Yong; Wang, Chi; Xu, Jiyao; Li, Xiaoyu; Klecker, Berndt

    2015-04-01

    The Magnetosphere, Ionosphere and Thermosphere (MIT) mission is one of the Space Science Strategic Pioneer Projects of the Chinese Academy of Sciences (CAS). Its major scientific objectives focus on the heating, acceleration and transport processes of ions in the polar regions and on their impact on the ring current and radiation belts. Because of the dynamic nature of these processes that also vary with altitude, it is imperative to cover with MIT altitudes from a few 100 km to several earth radii. This will be accomplished with a novel constellation of four spacecraft in polar orbits that provide periodic simultaneous measurements in the polar regions at three different altitudes. The two Ionospheric spacecraft have a polar orbit of 500km*1500km. The other two spacecraft have symmetric polar orbits with geocentric distances of 2Re*8Re (Re is the radius of the Earth). With instrument packages covering particle and field measurements over a wide energy range on all four spacecraft we will be able to monitor and investigate all relevant processes, including ion outflow from the source region in the ionosphere, their acceleration at mid-altitudes, to their final destination in the magnetosphere. Presently, MIT is in the background study stage that will be completed in 2015, with the engineering stage planed to start in 2016, if selected.

  7. Crystal Structures of Mite Allergens Der f 1 and Der p 1 Reveal Differences in Surface-Exposed Residues that May Influence Antibody Binding

    SciTech Connect

    Chruszcz, Maksymilian; Chapman, Martin D.; Vailes, Lisa D.; Stura, Enrico A.; Saint-Remy, Jean-Marie; Minor, Wladek; Pomés, Anna

    2009-12-01

    The Group 1 mite allergens, Der f 1 and Der p 1, are potent allergens excreted by Dermatophagoides farinae and Dermatophagoides pteronyssinus, respectively. The human IgE antibody responses to the Group 1 allergens show more cross-reactivity than the murine IgG antibody responses which are largely species-specific. Here, we report the crystal structure of the mature form of Der f 1, which was isolated from its natural source, and a new, high-resolution structure of mature recombinant Der p 1. Unlike Der p 1, Der f 1 is monomeric both in the crystalline state and in solution. Moreover, no metal binding is observed in the structure of Der f 1, despite the fact that all amino acids involved in Ca{sup 2+} binding in Der p 1 are completely conserved in Der f 1. Although Der p 1 and Der f 1 share extensive sequence identity, comparison of the crystal structures of both allergens revealed structural features which could explain the differences in murine and human IgE antibody responses to these allergens. There are structural differences between Der f 1 and Der p 1 which are unevenly distributed on the allergens' surfaces. This uneven spatial arrangement of conserved versus altered residues could explain both the specificity and cross-reactivity of antibodies against Der f 1 and Der p 1.

  8. Teaching practical leadership in MIT satellite development class: CASTOR and Exoplanet projects

    NASA Astrophysics Data System (ADS)

    Babuscia, Alessandra; Craig, Jennifer L.; Connor, Jane A.

    2012-08-01

    For more than a decade, the Aeronautics and Astronautics Department at MIT has offered undergraduate students the opportunity of conceiving, developing, implementing and operating new spacecraft's missions. During a three term class, junior and senior students experience all the challenges of a true engineering team project: design, analysis, testing, technical documentation development, team management, and leadership. Leadership instruction is an important part of the curricula; through the development of leadership skills, students learn to manage themselves and each other in a more effective way, increasing the overall productivity of the team. Also, a strong leadership education is a key factor in improving the abilities of future engineers to be effective team members and leaders in the companies and agencies in which they will work. However, too often leadership instruction is presented in an abstract way, which does not provide students with suggestions for immediate applicability. As a consequence, students underestimate the potential that leadership education can have on the development of their projects. To counteract that effect, a new approach for teaching "practical" leadership has been developed. This approach is composed of a set of activities developed to improve students' leadership skills in the context of a project. Specifically, this approach has been implemented in the MIT satellite development class. In that class, students experienced the challenges of building two satellites: CASTOR and Exoplanet. These two missions are real space projects which will be launched in the next two years, and which involve cooperation with different entities (MIT, NASA, and Draper). Hence, the MIT faculty was interested in developing leadership activities to improve the productivity of the teams in a short time. In fact, one of the key aspects of the approach proposed is that it can be quickly implemented in a single semester, requiring no more than 4 h of

  9. Deletion of PdMit1, a homolog of yeast Csg1, affects growth and Ca(2+) sensitivity of the fungus Penicillium digitatum, but does not alter virulence.

    PubMed

    Zhu, Congyi; Wang, Weili; Wang, Mingshuang; Ruan, Ruoxin; Sun, Xuepeng; He, Meixian; Mao, Cungui; Li, Hongye

    2015-04-01

    GDP-mannose:inositol-phosphorylceramide (MIPC) and its derivatives are important for Ca(2+) sensitization of Saccharomyces cerevisiae and for the virulence of Candida albicans, but its role in the virulence of plant fungal pathogens remains unclear. In this study, we report the identification and functional characterization of PdMit1, the gene encoding MIPC synthase in Penicillium digitatum, one of the most important pathogens of postharvest citrus fruits. To understand the function of PdMit1, a PdMit1 deletion mutant was generated. Compared to its wild-type control, the PdMit1 deletion mutant exhibited slow radial growth, decreased conidia production and delayed conidial germination, suggesting that PdMit1 is important for the growth of mycelium, sporulation and conidial germination. The PdMit1 deletion mutant also showed hypersensitivity to Ca(2+). Treatment with 250 mmol/l Ca(2+) induced vacuole fusion in the wild-type strain, but not in the PdMit1 deletion mutant. Treatment with 250mmol/lCaCl2 upregulated three Ca(2+)-ATPase genes in the wild-type strain, and this was significantly inhibited in the PdMit1 deletion mutant. These results suggest that PdMit1 may have a role in regulating vacuole fusion and expression of Ca(2+)-ATPase genes by controlling biosynthesis of MIPC, and thereby imparts P. digitatum Ca(2+) tolerance. However, we found that PdMit1 is dispensable for virulence of P. digitatum.

  10. 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.

  11. elecTUM: Umsetzung der eLearning-Strategie der Technischen Universität München

    NASA Astrophysics Data System (ADS)

    Rathmayer, Sabine; Gergintchev, Ivan

    An der TUM wurde ein umfassendes und integriertes eLearning-Konzept umgesetzt, welches Präsenzstudium und eLearning in allen Leistungsbereichen der Universität miteinander verzahnt. Ein besonderer Schwerpunkt lag dabei in der Schaffung einer effizienten und wettbewerbsfähigen integrierten eLearning Infrastruktur in Hinblick auf die noch weiter steigenden Studienanfängerzahlen ab dem Jahr 2011 sowie die Umsetzung von eBologna. Die Etablierung einer hochschulweiten Lernplattform stellte eine wesentliche Basis für die Umsetzung der eLearning-Strategie dar. Die wissenschaftliche und wirtschaftliche Anschlussfähigkeit im Hinblick auf eine Verwertung der Projektergebnisse wurde durch die aktive Beteiligung an einer Vielzahl hochschulübergreifender Arbeitskreise, Fachtagungen und Kooperationen, vor allem über Organisations- und Dienstleistungsmodelle sowie innovative technische Entwicklungen, sichergestellt.

  12. Prospective pilot trial of PerMIT versus standard anticoagulation service management of patients initiating oral anticoagulation.

    PubMed

    Borgman, Mark P; Pendleton, Robert C; McMillin, Gwendolyn A; Reynolds, Kristen K; Vazquez, Sara; Freeman, Andrew; Wilson, Andrew; Valdes, Roland; Linder, Mark W

    2012-09-01

    We performed a randomised pilot trial of PerMIT, a novel decision support tool for genotype-based warfarin initiation and maintenance dosing, to assess its efficacy for improving warfarin management. We prospectively studied 26 subjects to compare PerMIT-guided management with routine anticoagulation service management. CYP2C9 and VKORC1 genotype results for 13 subjects randomly assigned to the PerMIT arm were recorded within 24 hours of enrolment. To aid in INR interpretation, PerMIT calculates estimated loading and maintenance doses based on a patient's genetic and clinical characteristics and displays calculated S-warfarin plasma concentrations based on planned or administered dosages. In comparison to control subjects, patients in the PerMIT study arm demonstrated a 3.6-day decrease in the time to reach a stabilised INR within the target therapeutic range (4.7 vs. 8.3 days, p = 0.015); a 12.8% increase in time spent within the therapeutic interval over the first 25 days of therapy (64.3% vs. 55.3%, p = 0.180); and a 32.9% decrease in the frequency of warfarin dose adjustments per INR measurement (38.3% vs. 57.1%, p = 0.007). Serial measurements of plasma S-warfarin concentrations were also obtained to prospectively evaluate the accuracy of the pharmacokinetic model during induction therapy. The PerMIT S-warfarin plasma concentration model estimated 62.8% of concentrations within 0.15 mg/l. These pilot data suggest that the PerMIT method and its incorporation of genotype/phenotype information may help practitioners increase the safety, efficacy, and efficiency of warfarin therapeutic management. PMID:22836303

  13. MitProNet: A knowledgebase and analysis platform of proteome, interactome and diseases for mammalian mitochondria.

    PubMed

    Wang, Jiabin; Yang, Jian; Mao, Song; Chai, Xiaoqiang; Hu, Yuling; Hou, Xugang; Tang, Yiheng; Bi, Cheng; Li, Xiao

    2014-01-01

    Mitochondrion plays a central role in diverse biological processes in most eukaryotes, and its dysfunctions are critically involved in a large number of diseases and the aging process. A systematic identification of mitochondrial proteomes and characterization of functional linkages among mitochondrial proteins are fundamental in understanding the mechanisms underlying biological functions and human diseases associated with mitochondria. Here we present a database MitProNet which provides a comprehensive knowledgebase for mitochondrial proteome, interactome and human diseases. First an inventory of mammalian mitochondrial proteins was compiled by widely collecting proteomic datasets, and the proteins were classified by machine learning to achieve a high-confidence list of mitochondrial proteins. The current version of MitProNet covers 1124 high-confidence proteins, and the remainders were further classified as middle- or low-confidence. An organelle-specific network of functional linkages among mitochondrial proteins was then generated by integrating genomic features encoded by a wide range of datasets including genomic context, gene expression profiles, protein-protein interactions, functional similarity and metabolic pathways. The functional-linkage network should be a valuable resource for the study of biological functions of mitochondrial proteins and human mitochondrial diseases. Furthermore, we utilized the network to predict candidate genes for mitochondrial diseases using prioritization algorithms. All proteins, functional linkages and disease candidate genes in MitProNet were annotated according to the information collected from their original sources including GO, GEO, OMIM, KEGG, MIPS, HPRD and so on. MitProNet features a user-friendly graphic visualization interface to present functional analysis of linkage networks. As an up-to-date database and analysis platform, MitProNet should be particularly helpful in comprehensive studies of complicated

  14. Der f 21, a novel allergen from dermatophagoides farina.

    PubMed

    Wu, Yulan; Jiang, Congli; Li, Meng; Yu, Haiqiong; Xiao, Xiaojun; Fan, Xiaoqin; Lin, Jianli; Liu, Xiaoyu; Zhang, Min; Yang, Pingchang; Liu, Zhigang

    2016-01-01

    The Dermatophagoides farina (D. farina) allergens are an important factor contributing to allergic disease. To identify new allergens is important for diagnosis and treatment of allergic diseases. In this study, we sought to characterize the biological activity of Der f 21 of D. farina. The recombinant Der f 21 protein was characterized by western-blot, ELISA and Skin prick test using clinic patient's serum.An allergic asthma mouse model was established with the rDer f 21 as a specific antigen. The results showed that the sera from 28.9% in 38 dust mite allergic children displayed positive results in response to rDer f 21, and 42% in 98 dust mite allergic patients displayed positive response in skin prick test. In addition, Immune inhibition assays showed there was IgE cross-reactivity between rDer f 21 and rDer f 5. Moreover, an allergic asthma mouse model was established. Airway hyperresponsiveness, serum specific IgE, IgG1, eosinophil infiltration in the allergic mice, interleukin-4(IL-4) and interferon-γ (INF-γ) from spleen cells were markedly increased in the allergic mice. The results demonstrate that Der f 21 is a novel allergen.

  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. Kernschmelze Der nachhaltige Einfluss von Nuklearwaffen auf Politik und Wirtschaft

    NASA Astrophysics Data System (ADS)

    Greiner, Bernd

    "Was sollen wir von einer Kultur halten, der die Ethik stets als wesentliches Element des menschlichen Lebens galt, die aber - außer in fachlicher oder spieltheoretischer Terminologie - nicht in der Lage war, über die Möglichkeit zu sprechen, nahezu alle Menschen zu töten?" Der Fragesteller gehört zu den berühmtesten Physikern des 20. Jahrhunderts und zu den nach wie vor Umstrittensten. über ihn wurde in den 1960er Jahren ein international viel beachtetes Theaterstück geschrieben, vor wenigen Jahren gar eine Oper.

  17. Einsteins Spuren in den Archiven der Wissenschaft: Physikgeschichte

    NASA Astrophysics Data System (ADS)

    Marx, Werner

    2005-07-01

    Die Erwähnungen und Zitierungen von Einsteins Arbeiten dokumentieren lediglich den quantifizierbaren Anteil von Einsteins Beitrag zur Physik. Gleichwohl belegen sie die außergewöhnliche Resonanz und Langzeitwirkung seiner Arbeiten. Die Häufigkeit der Zitierungen entspricht nicht der allgemeinen Einschätzung ihrer Bedeutung. Insbesondere die Pionierarbeiten werden inzwischen als bekannt vorausgesetzt und nicht mehr explizit zitiert. Interessanterweise ist seine nach 1945 meist zitierte Arbeit nicht eine der Pionierarbeiten zur Quantenphysik oder Relativitätstheorie, sondern jene aus dem Jahr 1935 zum berühmten Einstein-Podolsky-Rosen-Paradoxon.

  18. Regional climate projection of the Maritime Continent using the MIT Regional Climate Model

    NASA Astrophysics Data System (ADS)

    IM, E. S.; Eltahir, E. A. B.

    2014-12-01

    Given that warming of the climate system is unequivocal (IPCC AR5), accurate assessment of future climate is essential to understand the impact of climate change due to global warming. Modelling the climate change of the Maritime Continent is particularly challenge, showing a high degree of uncertainty. Compared to other regions, model agreement of future projections in response to anthropogenic emission forcings is much less. Furthermore, the spatial and temporal behaviors of climate projections seem to vary significantly due to a complex geographical condition and a wide range of scale interactions. For the fine-scale climate information (27 km) suitable for representing the complexity of climate change over the Maritime Continent, dynamical downscaling is performed using the MIT regional climate model (MRCM) during two thirty-year period for reference (1970-1999) and future (2070-2099) climate. Initial and boundary conditions are provided by Community Earth System Model (CESM) simulations under the emission scenarios projected by MIT Integrated Global System Model (IGSM). Changes in mean climate as well as the frequency and intensity of extreme climate events are investigated at various temporal and spatial scales. Our analysis is primarily centered on the different behavior of changes in convective and large-scale precipitation over land vs. ocean during dry vs. wet season. In addition, we attempt to find the added value to downscaled results over the Maritime Continent through the comparison between MRCM and CESM projection. Acknowledgements.This research was supported by the National Research Foundation Singapore through the Singapore MIT Alliance for Research and Technology's Center for Environmental Sensing and Modeling interdisciplinary research program.

  19. Sampling Technique for Robust Odorant Detection Based on MIT RealNose Data

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A.

    2012-01-01

    This technique enhances the detection capability of the autonomous Real-Nose system from MIT to detect odorants and their concentrations in noisy and transient environments. The lowcost, portable system with low power consumption will operate at high speed and is suited for unmanned and remotely operated long-life applications. A deterministic mathematical model was developed to detect odorants and calculate their concentration in noisy environments. Real data from MIT's NanoNose was examined, from which a signal conditioning technique was proposed to enable robust odorant detection for the RealNose system. Its sensitivity can reach to sub-part-per-billion (sub-ppb). A Space Invariant Independent Component Analysis (SPICA) algorithm was developed to deal with non-linear mixing that is an over-complete case, and it is used as a preprocessing step to recover the original odorant sources for detection. This approach, combined with the Cascade Error Projection (CEP) Neural Network algorithm, was used to perform odorant identification. Signal conditioning is used to identify potential processing windows to enable robust detection for autonomous systems. So far, the software has been developed and evaluated with current data sets provided by the MIT team. However, continuous data streams are made available where even the occurrence of a new odorant is unannounced and needs to be noticed by the system autonomously before its unambiguous detection. The challenge for the software is to be able to separate the potential valid signal from the odorant and from the noisy transition region when the odorant is just introduced.

  20. Lasers, their development, and applications at M.I.T. Lincoln Laboratory

    NASA Technical Reports Server (NTRS)

    Rediker, R. H.; Melngailis, I.; Mooradian, A.

    1984-01-01

    A historical account of the work on lasers at MIT Lincoln Laboratory is presented. Highlighted are the efforts that led to the coinvention of the semiconductor laser and the Laboratory's later role in establishing the feasibility of GaInAsP/InP semiconductor lasers for use in fiber telecommunications at 1.3-1.5 micron wavelengths. Descriptions of other important developments include tunable lead-salt semiconductor and solid-state lasers for spectroscopy and LIDAR applications, respectively, as well as ultrastable CO2 lasers for coherent infrared radar.

  1. Charakterisierung von Sulfotransferasen im Gastrointestinaltrakt von Mensch und Ratte und Aktivierung von Promutagenen in V79-Zellen, die eine intestinale Form (1B1) des Menschen und der Ratte exprimieren

    NASA Astrophysics Data System (ADS)

    Teubner, Wera

    2001-05-01

    Die Ausstattung der gastrointestinalen Mukosa des Menschen und der Ratte mit Sulfotransferasen wurde mit Hilfe von Immunodetektion und Enzymaktivitätsmessungen untersucht. In Proben aus Colon und Rektum von 39 Personen wurden die Formen h1A1, h1A3 und h1B1 identifiziert, wobei in einer weiteren Probe, die als einzige von einem an Colitis Ulcerosa erkrankten Patienten stammte, keine Sulfotransferasen nachgewiesen werden konnten. Bei der Immunblot-Analyse war das Expressionsmuster der einzelnen Formen in allen Proben ähnlich. In wenigen Proben waren die relativen Signalintensitäten der h1A1 und der h1B1 um die Hälfte erniedrigt. Der Gehalt von SULT an zytosolischem Protein zeigte einen bis zu 8 - 10fachen Unterschied, er betrug jedoch bei zwei Dritteln der Proben zwischen 0,15 und 0,3 (h1A1 und h1A3) bzw. 0,6 und 0,8 Promille (h1B1). Die Variation konnte nicht auf Alter, Geschlecht oder Krankheitsbild der Patienten zurückgeführt werden. Auch der für die allelischen Varianten der h1A1 beschriebene Effekt auf die Enzymaktiviät bzw. Stabilität konnte in der Menge an immunreaktivem Protein nicht in diesem Ausma detektiert werden. Die Allelhäufigkeit von h1A1*R und h1A1*H war gegenüber der gesunden Bevölkerung nicht verändert. In den sieben Proben aus dem Dünndarm (Coecum, viermal Ileum, Jejunum) konnten zusätzlich die Formen h1E1 und h2A1 identifiziert werden. Ein möglicherweise der Form h1C1 entsprechendes Protein wurde im Magen detektiert. Im Vergleich zum Menschen war die Expression in der Ratte stärker auf die Leber konzentriert. Während beim Menschen in allen untersuchten Abschnitten Sulfotransferasen in Mengen detektiert wurden, die in zwei Fällen (h1B1 und h1A3) sogar den Gehalt in der Leber überstiegen, beschränkte sich die Expression in der Ratte auf im Vergleich zur Leber geringe Mengen im Magen und Dickdarm. Nachgewiesen wurden die r1B1, r1A1 sowie eine nicht identifizierte Form von 35kD, bei der es sich vermutlich um die r1C2 handelt. Im

  2. 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.

  3. MitBASE : a comprehensive and integrated mitochondrial DNA database. The present status

    PubMed Central

    Attimonelli, M.; Altamura, N.; Benne, R.; Brennicke, A.; Cooper, J. M.; D’Elia, D.; Montalvo, A. de; Pinto, B. de; De Robertis, M.; Golik, P.; Knoop, V.; Lanave, C.; Lazowska, J.; Licciulli, F.; Malladi, B. S.; Memeo, F.; Monnerot, M.; Pasimeni, R.; Pilbout, S.; Schapira, A. H. V.; Sloof, P.; Saccone, C.

    2000-01-01

    MitBASE is an integrated and comprehensive database of mitochondrial DNA data which collects, under a single interface, databases for Plant, Vertebrate, Invertebrate, Human, Protist and Fungal mtDNA and a Pilot database on nuclear genes involved in mitochondrial biogenesis in Saccharomyces cerevisiae. MitBASE reports all available information from different organisms and from intraspecies variants and mutants. Data have been drawn from the primary databases and from the literature; value adding information has been structured, e.g., editing information on protist mtDNA genomes, pathological information for human mtDNA variants, etc. The different databases, some of which are structured using commercial packages (Microsoft Access, File Maker Pro) while others use a flat-file format, have been integrated under ORACLE. Ad hoc retrieval systems have been devised for some of the above listed databases keeping into account their peculiarities. The database is resident at the EBI and is available at the following site: http://www3.ebi.ac.uk/Research/Mitbase/mitbase.pl . The impact of this project is intended for both basic and applied research. The study of mitochondrial genetic diseases and mitochondrial DNA intraspecies diversity are key topics in several biotechnological fields. The database has been funded within the EU Biotechnology programme. PMID:10592207

  4. Evaluation of Dynamics of the West African Monsoon Jump Simulated by the MIT Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Eltahir, Elfatih A. B.; Im, Eun-Soon

    2015-04-01

    The seasonal advance and retreat of the West African monsoon behaves abrupt northward jump of maximum rainfall from the Guinean coast to the Sahel region. Both global and regional climate models have difficulties in accurately reproducing such a behavior due to its complexity combined the dynamical and physical processes. In this study, we evaluate the performance of the MIT Regional Climate Model (MRCM) in simulating the West African monsoon. For this, 20-year long-term simulation (1989-2008) is performed using the ERAInterim reanalysis as the initial and boundary condition, and the analysis primarily focuses on the dynamics associated with abrupt phase transitions of the monsoon rainfall. We first examine detailed characteristics in terms of the onset, maximum, and retreat of the monsoon rainfall using daily precipitation. We then present the dynamical explanation behind rainfall variability from the analysis of the absolute vorticity near the tropopause and the meridional gradient of boundary-layer entropy within the dynamical theory proposed by Eltahir and Gong (1996). Acknowledgements : This research was supported by the National Research Foundation Singapore through the Singapore MIT Alliance for Research and Technology's Center for Environmental Sensing and Modeling interdisciplinary research program.

  5. How Much Have They Retained? Making Unseen Concepts Seen in a Freshman Electromagnetism Course at MIT

    NASA Astrophysics Data System (ADS)

    Dori, Yehudit Judy; Hult, Erin; Breslow, Lori; Belcher, John W.

    2007-08-01

    The introductory freshmen electromagnetism course at MIT has been taught since 2000 using a studio physics format entitled TEAL—Technology Enabled Active Learning. TEAL has created a collaborative, hands-on environment where students carry out desktop experiments, submit web-based assignments, and have access to a host of visualizations and simulations. These learning tools help them visualize unseen electromagnetic concepts and develop stronger intuition about related phenomena. A previous study has shown that students who took the course in the TEAL format (the experimental group) gained significantly better conceptual understanding than those who took it in the traditional lecture-recitation format (the control group). The present longitudinal study focuses on the extent to which these two research groups (experimental and control) retain conceptual understanding about a year to 18 months after finishing the course. It also examines students attitudes about whether the teaching format (TEAL or traditional) contributes to their learning in advanced courses. Our research has indicated that the long-term effect of the TEAL course on students' retention of concepts was significantly stronger than that of the traditional course. This research is significant because it documents the long-term cognitive and affective impact of the TEAL studio physics format on learning outcomes of MIT students.

  6. Distinct mechanisms of recognizing endosomal sorting complex required for transport III (ESCRT-III) protein IST1 by different microtubule interacting and trafficking (MIT) domains.

    PubMed

    Guo, Emily Z; Xu, Zhaohui

    2015-03-27

    The endosomal sorting complex required for transport (ESCRT) machinery is responsible for membrane remodeling in a number of biological processes including multivesicular body biogenesis, cytokinesis, and enveloped virus budding. In mammalian cells, efficient abscission during cytokinesis requires proper function of the ESCRT-III protein IST1, which binds to the microtubule interacting and trafficking (MIT) domains of VPS4, LIP5, and Spartin via its C-terminal MIT-interacting motif (MIM). Here, we studied the molecular interactions between IST1 and the three MIT domain-containing proteins to understand the structural basis that governs pairwise MIT-MIM interaction. Crystal structures of the three molecular complexes revealed that IST1 binds to the MIT domains of VPS4, LIP5, and Spartin using two different mechanisms (MIM1 mode versus MIM3 mode). Structural comparison revealed that structural features in both MIT and MIM contribute to determine the specific binding mechanism. Within the IST1 MIM sequence, two phenylalanine residues were shown to be important in discriminating MIM1 versus MIM3 binding. These observations enabled us to deduce a preliminary binding code, which we applied to provide CHMP2A, a protein that normally only binds the MIT domain in the MIM1 mode, the additional ability to bind the MIT domain of Spartin in the MIM3 mode.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Stufenweise Integration von eLearning an der Technischen Universität München

    NASA Astrophysics Data System (ADS)

    Pätzold, Sebastian; Graf, Stephan; Gergintchev, Ivan; Pongratz, Hans; Rathmayer, Sabine

    Der vorliegende Beitrag beschreibt als Best Practice Beispiel die stufenweise Integration eines Learning Management Systems (LMS) in die Infrastruktur von Information und Kommunikation (IuK) der Technischen Universität München (TUM). Dabei wird sowohl die Konsolidierung mehrfach angebotener Funktionalitäten und Dienste in den verschiedenen Portalen der Universität als auch die sukzessive Optimierung der Abläufe aufgezeigt. Gleichzeitig wird auf zukünftige weitere Entwicklungen hin zu einer vollständigen Integration der IuK, aber auch auf die Probleme in den unterschiedlichen Stadien der Entwicklung eingegangen.

  15. Advanced Communication and Control Solutions of Distributed Energy Resources (DER)

    SciTech Connect

    Asgeirsson, Haukur; Seguin, Richard; Sherding, Cameron; de Bruet, Andre, G.; Broadwater, Robert; Dilek, Murat

    2007-01-10

    This report covers work performed in Phase II of a two phase project whose objective was to demonstrate the aggregation of multiple Distributed Energy Resources (DERs) and to offer them into the energy market. The Phase I work (DE-FC36-03CH11161) created an integrated, but distributed, system and procedures to monitor and control multiple DERs from numerous manufacturers connected to the electric distribution system. Procedures were created which protect the distribution network and personnel that may be working on the network. Using the web as the communication medium for control and monitoring of the DERs, the integration of information and security was accomplished through the use of industry standard protocols such as secure SSL,VPN and ICCP. The primary objective of Phase II was to develop the procedures for marketing the power of the Phase I aggregated DERs in the energy market, increase the number of DER units, and implement the marketing procedures (interface with ISOs) for the DER generated power. The team partnered with the Midwest Independent System Operator (MISO), the local ISO, to address the energy market and demonstrate the economic dispatch of DERs in response to market signals. The selection of standards-based communication technologies offers the ability of the system to be deployed and integrated with other utilities’ resources. With the use of a data historian technology to facilitate the aggregation, the developed algorithms and procedures can be verified, audited, and modified. The team has demonstrated monitoring and control of multiple DERs as outlined in phase I report including procedures to perform these operations in a secure and safe manner. In Phase II, additional DER units were added. We also expanded on our phase I work to enhance communication security and to develop the market model of having DERs, both customer and utility owned, participate in the energy market. We are proposing a two-part DER energy market model--a utility

  16. Deletion of PdMit1, a homolog of yeast Csg1, affects growth and Ca2+ sensitivity of the fungus Penicillium digitatum, but does not alter virulence

    PubMed Central

    Zhu, Congyi; Wang, Weili; Wang, Mingshuang; Ruan, Ruoxin; Sun, Xuepeng; He, Meixian; Mao, Cungui; Li, Hongye

    2015-01-01

    GDP-mannose:inositol-phosphorylceramide (MIPC) and its derivatives are important for Ca2+ sensitization of Saccharomyces cerevisiae and for the virulence of Candida albicans, but its role in the virulence of plant fungal pathogens remains unclear. In this study, we report the identification and functional characterization of PdMit1, the gene encoding MIPC synthase in Penicillium digitatum, one of the most important pathogens of postharvest citrus fruits. To understand the function of PdMit1, a PdMit1 deletion mutant was generated. Compared to its wild-type control, the PdMit1 deletion mutant exhibited slow radial growth, decreased conidia production and delayed conidial germination, suggesting that PdMit1 is important for the growth of mycelium, sporulation and conidial germination. The PdMit1 deletion mutant also showed hypersensitivity to Ca2+. Treatment with 250 mmol/l Ca2+ induced vacuole fusion in the wild-type strain, but not in the PdMit1 deletion mutant. Treatment with 250 mmol/lCaCl2 upregulated three Ca2+-ATPase genes in the wild-type strain, and this was significantly inhibited in the PdMit1 deletion mutant. These results suggest that PdMit1 may have a role in regulating vacuole fusion and expression of Ca2+-ATPase genes by controlling biosynthesis of MIPC, and thereby imparts P. digitatum Ca2+ tolerance. However, we found that PdMit1 is dispensable for virulence of P. digitatum. PMID:25725383

  17. Draft Genome Sequences of Supercritical CO2-Tolerant Bacteria Bacillus subterraneus MITOT1 and Bacillus cereus MIT0214.

    PubMed

    Peet, Kyle C; Thompson, Janelle R

    2015-01-01

    We report draft genome sequences of Bacillus subterraneus MITOT1 and Bacillus cereus MIT0214 isolated through enrichment of samples from geologic sequestration sites in pressurized bioreactors containing a supercritical (sc) CO2 headspace. Their genome sequences expand the phylogenetic range of sequenced bacilli and allow characterization of molecular mechanisms of scCO2 tolerance.

  18. Evaluation of the MIT RMID 1000 system for the identification of Listeria species:AOAC performance tested method 090325

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The MIT 1000 RMID System is a rapid microbial identification device that uses the principles of light scattering coupled with proprietary algorithms to identify bacteria after being cultured and placed in a vial of filtered water. This specific method is for pure culture identification of Listeria ...

  19. Interactive Web-Based and Hands-On Engineering Education: A Freshman Aerospace Design Course at MIT.

    ERIC Educational Resources Information Center

    Newman, Dava J.

    "Introduction to Aerospace and Design" is a 3-hour per week freshman elective course at Massachusetts Institute of Technology (MIT) that culminates in a Lighter-Than-Air (LTA) vehicle design competition, exposing freshmen to the excitement of aerospace engineering design typically taught in the junior or senior years. In addition to the hands-on…

  20. Excellence in Research: Creative Organizational Responses at Berkeley, Harvard, MIT, and Stanford. ASHE 1985 Annual Meeting Paper.

    ERIC Educational Resources Information Center

    Gardiner, John J.

    Research environments of four leading universities were studied: University of California at Berkeley (UC-Berkeley), Harvard University, Massachusetts Institute of Technology (MIT), and Stanford University. Attention was directed to organizational responses for encouraging collaboration in research at these leading universities, as well as to…

  1. Rapid identification of Listeria spp.: an AOAC performance test of the MIT 1000 rapid microbial identification system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methods that rapidly confirm the identification of foodborne pathogens are highly desired. The Micro Imaging Technology (MIT) 1000 Rapid Microbial Identification (RMID) System is a benchtop instrument that detects laser light scattered from individual bacterial cells in solution with an array of 35 ...

  2. Understanding the Self-Directed Online Learning Preferences, Goals, Achievements, and Challenges of MIT OpenCourseWare Subscribers

    ERIC Educational Resources Information Center

    Bonk, Curtis J.; Lee, Mimi Miyoung; Kou, Xiaojing; Xu, Shuya; Sheu, Feng-Ru

    2015-01-01

    This research targeted the learning preferences, goals and motivations, achievements, challenges, and possibilities for life change of self-directed online learners who subscribed to the monthly OpenCourseWare (OCW) e-newsletter from MIT. Data collection included a 25-item survey of 1,429 newsletter subscribers; 613 of whom also completed an…

  3. Designing Materials for the Language Lab of the Future: An Overview of the MIT Athena Language Learning Project.

    ERIC Educational Resources Information Center

    Kramsch, Claire; And Others

    1985-01-01

    Details the current status, the future plans and the reasoning behind a five-year, campus-wide educational experiment for the integration of computers into the foreign language curriculum at MIT. The project is to use artificial intelligence in natural processing and to include interactive video and interactive audio components. (Author/SED)

  4. Trouble and Triumph: German Life-Turkish Tradition in Renan Demirkan's "Schwarzer Tee mit drei Stuck Zucker"

    ERIC Educational Resources Information Center

    Ebert, Reika

    2004-01-01

    This paper explores Demirkan's narrative strategies in "Schwarzer Tee mit drei Stuck Zucker" to negotiate issues of a life between two cultures and traditions. Based on Bhabha's insights that mainstream culture needs intellectual and artistic infusion from the margins of a society in order to remain vital; and that cultural production itself is a…

  5. Whistler mode based explanation for the fast reconnection rate measured in the mit versatile toroidal facility.

    PubMed

    Singh, Nagendra

    2011-12-01

    Despite the widely discussed role of whistler waves in mediating magnetic reconnection (MR), the direct connection between such waves and the MR has not been demonstrated by comparing the characteristic temporal and spatial features of the waves and the MR process. Using the whistler wave dispersion relation, we theoretically predict the experimentally measured rise time (τ(rise)) of a few microseconds for the fast rising MR rate in the Versatile Toroidal Facility at MIT. The rise time is closely given by the inverse of the frequency bandwidth of the whistler waves generated in the evolving current sheet. The wave frequencies lie much above the ion cyclotron frequency, but they are limited to less than 0.1% of the electron cyclotron frequency in the argon plasma. The maximum normalized MR rate R=0.35 measured experimentally is precisely predicted by the angular dispersion of the whistler waves.

  6. Oncogenic MITF dysregulation in clear cell sarcoma: defining the MiT family of human cancers.

    PubMed

    Davis, Ian J; Kim, Jessica J; Ozsolak, Fatih; Widlund, Hans R; Rozenblatt-Rosen, Orit; Granter, Scott R; Du, Jinyan; Fletcher, Jonathan A; Denny, Christopher T; Lessnick, Stephen L; Linehan, W Marston; Kung, Andrew L; Fisher, David E

    2006-06-01

    Clear cell sarcoma (CCS) harbors a pathognomonic chromosomal translocation fusing the Ewing's sarcoma gene (EWS) to the CREB family transcription factor ATF1 and exhibits melanocytic features. We show that EWS-ATF1 occupies the MITF promoter, mimicking melanocyte-stimulating hormone (MSH) signaling to induce expression of MITF, the melanocytic master transcription factor and an amplified oncogene in melanoma. Knockdown/rescue studies revealed that MITF mediates the requirement of EWS-ATF1 for CCS survival in vitro and in vivo as well as for melanocytic differentiation. Moreover, MITF and TFE3 reciprocally rescue one another in lines derived from CCS or pediatric renal carcinoma. Seemingly unrelated tumors thus employ distinct strategies to oncogenically dysregulate the MiT family, collectively broadening the definition of MiT-associated human cancers.

  7. MIT-NASA/KSC space life science experiments - A telescience testbed

    NASA Technical Reports Server (NTRS)

    Oman, Charles M.; Lichtenberg, Byron K.; Fiser, Richard L.; Vordermark, Deborah S.

    1990-01-01

    Experiments performed at MIT to better define Space Station information system telescience requirements for effective remote coaching of astronauts by principal investigators (PI) on the ground are described. The experiments were conducted via satellite video, data, and voice links to surrogate crewmembers working in a laboratory at NASA's Kennedy Space Center. Teams of two PIs and two crewmembers performed two different space life sciences experiments. During 19 three-hour interactive sessions, a variety of test conditions were explored. Since bit rate limits are necessarily imposed on Space Station video experiments surveillance video was varied down to 50 Kb/s and the effectiveness of PI controlled frame rate, resolution, grey scale, and color decimation was investigated. It is concluded that remote coaching by voice works and that dedicated crew-PI voice loops would be of great value on the Space Station.

  8. Space applications of the MITS electron-photon Monte Carlo transport code system

    SciTech Connect

    Kensek, R.P.; Lorence, L.J.; Halbleib, J.A.; Morel, J.E.

    1996-07-01

    The MITS multigroup/continuous-energy electron-photon Monte Carlo transport code system has matured to the point that it is capable of addressing more realistic three-dimensional adjoint applications. It is first employed to efficiently predict point doses as a function of source energy for simple three-dimensional experimental geometries exposed to simulated uniform isotropic planar sources of monoenergetic electrons up to 4.0 MeV. Results are in very good agreement with experimental data. It is then used to efficiently simulate dose to a detector in a subsystem of a GPS satellite due to its natural electron environment, employing a relatively complex model of the satellite. The capability for survivability analysis of space systems is demonstrated, and results are obtained with and without variance reduction.

  9. MC21 analysis of the MIT PWR benchmark: Hot zero power results

    SciTech Connect

    Kelly Iii, D. J.; Aviles, B. N.; Herman, B. R.

    2013-07-01

    MC21 Monte Carlo results have been compared with hot zero power measurements from an operating pressurized water reactor (PWR), as specified in a new full core PWR performance benchmark from the MIT Computational Reactor Physics Group. Included in the comparisons are axially integrated full core detector measurements, axial detector profiles, control rod bank worths, and temperature coefficients. Power depressions from grid spacers are seen clearly in the MC21 results. Application of Coarse Mesh Finite Difference (CMFD) acceleration within MC21 has been accomplished, resulting in a significant reduction of inactive batches necessary to converge the fission source. CMFD acceleration has also been shown to work seamlessly with the Uniform Fission Site (UFS) variance reduction method. (authors)

  10. Rapid Speech Transmission Index predictions and auralizations of unusual instructional spaces at MIT's new Stata Center

    NASA Astrophysics Data System (ADS)

    Conant, David A.

    2005-04-01

    The Stata Center for Computer, Information and Intelligence Sciences, recently opened at the Massachusetts Institute of Technology, includes a variety of oddly-shaped seminar rooms in addition to lecture spaces of somewhat more conventional form. The architects design approach prohibited following conventional, well understood room-acoustical behavior yet MIT and the design team were keenly interested in ensuring that these spaces functioned exceptionally well, acoustically. CATT-Acoustic room modeling was employed to assess RASTI through multiple design iterations for all these spaces. Presented here are computational and descriptive results achieved for these rooms which are highly-regarded by faculty. They all sound peculiarly good, given their unusual form. In addition, binaural auralizations for selected spaces are provided.

  11. Structure-based design and screening of inhibitors for an essential bacterial GTPase, Der.

    PubMed

    Hwang, Jihwan; Tseitin, Vladimir; Ramnarayan, Kal; Shenderovich, Mark D; Inouye, Masayori

    2012-05-01

    Der is an essential and widely conserved GTPase that assists assembly of a large ribosomal subunit in bacteria. Der associates specifically with the 50S subunit in a GTP-dependent manner and the cells depleted of Der accumulate the structurally unstable 50S subunit, which dissociates into an aberrant subunit at a lower Mg(2+) concentration. As Der is an essential and ubiquitous protein in bacteria, it may prove to be an ideal cellular target against which new antibiotics can be developed. In the present study, we describe our attempts to identify novel antibiotics specifically targeting Der GTPase. We performed the structure-based design of Der inhibitors using the X-ray crystal structure of Thermotoga maritima Der (TmDer). Virtual screening of commercially available chemical library retrieved 257 small molecules that potentially inhibit Der GTPase activity. These 257 chemicals were tested for their in vitro effects on TmDer GTPase and in vivo antibacterial activities. We identified three structurally diverse compounds, SBI-34462, -34566 and -34612, that are both biologically active against bacterial cells and putative enzymatic inhibitors of Der GTPase homologs. We also presented the possible interactions of each compound with the Der GTP-binding site to understand the mechanism of inhibition. Therefore, our lead compounds inhibiting Der GTPase provide scaffolds for the development of novel antibiotics against antibiotic-resistant pathogenic bacteria. PMID:22377538

  12. [Professor Hans Otto Lüders].

    PubMed

    Tsuji, Sadatoshi

    2014-11-01

    Professor Lüders has made significant contributions to Clinical Neurology and particularly to Epilepsy and Clinical Neurophysiology. Some of his most important contributions include the following: 1.He pioneered the use of chronically implanted, large plates of subdural electrodes in the presurgical evaluation of patient who were candidates for epilepsy surgery. These electrodes were used to record epileptic seizures and by electrical stimulation to establish the location of eloquent cortex. Lately he has also advocated the use in the USA of stereotactically implanted depth electrodes for presurgical evaluation of epilepsy patients who had deep seated epileptic foci which were impossible to assess with subdural electrodes. These techniques were imported from Europe. 2.Mapping studies with subdural electrodes led to the discovery of a number of cortical eloquent areas that had not been described before: a. The basal temporal language area located in the dominant fusiform gyrus. b. The "negative motor areas" located in the caudal region of the inferior frontal gyrus (bilaterally) and immediately in mesial frontal pre-SMA region (also bilaterally). He concluded that these "negative motor areas" most likely correspond to praxis regions. c. The dominant posterior fusiform gyrus which plays a crucial role in processing reading material. Stimulation of that area produces "alexia without agraphia". 3.He developed a new classification of epileptic seizures based exclusively on semiological ictal characteristics. With the development of the semiological seizure classification he also defined several new seizure types: a. Dialeptic seizures, b. Hypnopompic seizures, c. Hypomotor seizures. 4.Working with general epilepsy principles, he established the existence of 6 zones that characterize the epilepsies: the epileptogenic zone, the irritative zone, the seizure onset zone, the epileptogenic lesion, the symptomatogenic zone and functional deficit zone. 5.He described the ictal

  13. [Professor Hans Otto Lüders].

    PubMed

    Tsuji, Sadatoshi

    2014-11-01

    Professor Lüders has made significant contributions to Clinical Neurology and particularly to Epilepsy and Clinical Neurophysiology. Some of his most important contributions include the following: 1.He pioneered the use of chronically implanted, large plates of subdural electrodes in the presurgical evaluation of patient who were candidates for epilepsy surgery. These electrodes were used to record epileptic seizures and by electrical stimulation to establish the location of eloquent cortex. Lately he has also advocated the use in the USA of stereotactically implanted depth electrodes for presurgical evaluation of epilepsy patients who had deep seated epileptic foci which were impossible to assess with subdural electrodes. These techniques were imported from Europe. 2.Mapping studies with subdural electrodes led to the discovery of a number of cortical eloquent areas that had not been described before: a. The basal temporal language area located in the dominant fusiform gyrus. b. The "negative motor areas" located in the caudal region of the inferior frontal gyrus (bilaterally) and immediately in mesial frontal pre-SMA region (also bilaterally). He concluded that these "negative motor areas" most likely correspond to praxis regions. c. The dominant posterior fusiform gyrus which plays a crucial role in processing reading material. Stimulation of that area produces "alexia without agraphia". 3.He developed a new classification of epileptic seizures based exclusively on semiological ictal characteristics. With the development of the semiological seizure classification he also defined several new seizure types: a. Dialeptic seizures, b. Hypnopompic seizures, c. Hypomotor seizures. 4.Working with general epilepsy principles, he established the existence of 6 zones that characterize the epilepsies: the epileptogenic zone, the irritative zone, the seizure onset zone, the epileptogenic lesion, the symptomatogenic zone and functional deficit zone. 5.He described the ictal

  14. 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.

  15. Van der Waals interaction in uniaxial anisotropic media.

    PubMed

    Kornilovitch, Pavel E

    2013-01-23

    Van der Waals interactions between flat surfaces in uniaxial anisotropic media are investigated in the nonretarded limit. The main focus is the effect of nonzero tilt between the optical axis and the surface normal on the strength of the van der Waals attraction. General expressions for the van der Waals free energy are derived using the surface mode method and the transfer-matrix formalism. To facilitate numerical calculations a temperature-dependent three-band parameterization of the dielectric tensor of the liquid crystal 5CB is developed. A solid slab immersed in a liquid crystal experiences a van der Waals torque that aligns the surface normal relative to the optical axis of the medium. The preferred orientation is different for different materials. Two solid slabs in close proximity experience a van der Waals attraction that is strongest for homeotropic alignment of the intervening liquid crystal for all the materials studied. The results have implications for the stability of plate-like colloids in liquid crystal hosts. PMID:23234868

  16. Effects of tissue heterogeneity on single-coil, scanning MIT imaging

    NASA Astrophysics Data System (ADS)

    Feldkamp, J. R.; Quirk, S.

    2016-03-01

    We recently reported on the use of a single induction coil to accomplish imaging of the electrical conductivity in human tissues via magnetic induction tomography (MIT). A key to the method was the development of a mapping equation that quantitatively relates an arbitrary electrical conductivity distribution to ohmic loss in a coil consisting of concentric circular loops in a plane. By making multiple coil loss measurements at a number of locations in the vicinity of the target (scan), this mapping equation can be used to build an algorithm for 3D image construction of electrical conductivity. Important assumptions behind the mathematical formula included uniform relative permittivity throughout all space and continuous variation in conductivity. In this paper, these two assumptions were tested in a series of experiments involving the use of human tissue phantoms created from agarose, doped with sufficient sodium chloride to yield physiological conductivities. Inclusions of doped agarose were scanned both while isolated and also while embedded in a matrix of agarose gel having lowered conductivity - to help evaluate the effects of abrupt permittivity change. The effects of discontinuous conductivity change were simulated by filling 5 cm diameter petri dishes with 1.4% aqueous KCl and placing them in a much larger, 14 cm diameter petri dish - gap distance varied from about 3 mm to 30 mm. In either case, we will show that these effects are minimal on resultant images, helping to further validate the mapping equation used to construct MIT images. Because of their simplicity, scans reported here did not include coil rotation. To acknowledge the importance of rotation, however, we have devoted a section of this work to illustrate the profound benefits of coil rotation during a scan - though virtual data are used, where coil rotation is more easily specified.

  17. Entropy Generation/Availability Energy Loss Analysis Inside MIT Gas Spring and "Two Space" Test Rigs

    NASA Technical Reports Server (NTRS)

    Ebiana, Asuquo B.; Savadekar, Rupesh T.; Patel, Kaushal V.

    2006-01-01

    The results of the entropy generation and availability energy loss analysis under conditions of oscillating pressure and oscillating helium gas flow in two Massachusetts Institute of Technology (MIT) test rigs piston-cylinder and piston-cylinder-heat exchanger are presented. Two solution domains, the gas spring (single-space) in the piston-cylinder test rig and the gas spring + heat exchanger (two-space) in the piston-cylinder-heat exchanger test rig are of interest. Sage and CFD-ACE+ commercial numerical codes are used to obtain 1-D and 2-D computer models, respectively, of each of the two solution domains and to simulate the oscillating gas flow and heat transfer effects in these domains. Second law analysis is used to characterize the entropy generation and availability energy losses inside the two solution domains. Internal and external entropy generation and availability energy loss results predicted by Sage and CFD-ACE+ are compared. Thermodynamic loss analysis of simple systems such as the MIT test rigs are often useful to understand some important features of complex pattern forming processes in more complex systems like the Stirling engine. This study is aimed at improving numerical codes for the prediction of thermodynamic losses via the development of a loss post-processor. The incorporation of loss post-processors in Stirling engine numerical codes will facilitate Stirling engine performance optimization. Loss analysis using entropy-generation rates due to heat and fluid flow is a relatively new technique for assessing component performance. It offers a deep insight into the flow phenomena, allows a more exact calculation of losses than is possible with traditional means involving the application of loss correlations and provides an effective tool for improving component and overall system performance.

  18. Solarzellen aus Folien-Silizium: Neue Materialien der Photovoltaik

    NASA Astrophysics Data System (ADS)

    Hahn, Giso

    2004-01-01

    Die Photovoltaik wird auf absehbare Zeit vor allem kristallines Silizium als Baumaterial nutzen, mit Tendenz zu billigeren, multikristallinen Wafern. Allerdings werden heutige Wafer aus großen Silizium-Blöcken gesägt, was viel Material verpulvert. Das treibt den Anteil des Wafers an den Gesamtkosten des Solarmoduls auf 50% hoch. Folien-Silizium nutzt dagegen durch eine andere Herstellungstechnik das Material viel besser aus und senkt so die Waferkosten erheblich. Im Wirkungsgrad können Solarzellen aus Folien-Silizium schon fast mit herkömmlichen Zellen konkurrieren. Ein weiterer Vorteil von Folien-Silizium: Es kann relativ problemlos in die Produktionslinien heutiger Solarzellen aus kristallinem Silizium eingegliedert werden. Allerdings sind die attraktivsten Herstellungsverfahren noch nicht serienreif.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Web-gestütztes Social Networking am Beispiel der Plattform Wissensmanagement"

    NASA Astrophysics Data System (ADS)

    Lindstaedt, Stefanie; Thurner, Claudia

    Anhand der Plattform Wissensmanagement, der größten deutschsprachigen Community im Themenfeld Wissensmanagement, werden organisationale Rahmenbedingungen, technische Werkzeuge und Rollen der Moderatorin diskutiert, die Bedingungen für den erfolgreichen Betrieb einer Community im Web 2.0 sind. Weiters wird dargestellt, wie Communities für das betriebliche Wissensmanagement eingesetzt werden können.

  9. The MIT Integrated Global System Model: A facility for Assessing and Communicating Climate Change Uncertainty (Invited)

    NASA Astrophysics Data System (ADS)

    Prinn, R. G.

    2013-12-01

    The world is facing major challenges that create tensions between human development and environmental sustenance. In facing these challenges, computer models are invaluable tools for addressing the need for probabilistic approaches to forecasting. To illustrate this, I use the MIT Integrated Global System Model framework (IGSM; http://globalchange.mit.edu ). The IGSM consists of a set of coupled sub-models of global economic and technological development and resultant emissions, and physical, dynamical and chemical processes in the atmosphere, land, ocean and ecosystems (natural and managed). Some of the sub-models have both complex and simplified versions available, with the choice of which version to use being guided by the questions being addressed. Some sub-models (e.g.urban air pollution) are reduced forms of complex ones created by probabilistic collocation with polynomial chaos bases. Given the significant uncertainties in the model components, it is highly desirable that forecasts be probabilistic. We achieve this by running 400-member ensembles (Latin hypercube sampling) with different choices for key uncertain variables and processes within the human and natural system model components (pdfs of inputs estimated by model-observation comparisons, literature surveys, or expert elicitation). The IGSM has recently been used for probabilistic forecasts of climate, each using 400-member ensembles: one ensemble assumes no explicit climate mitigation policy and others assume increasingly stringent policies involving stabilization of greenhouse gases at various levels. These forecasts indicate clearly that the greatest effect of these policies is to lower the probability of extreme changes. The value of such probability analyses for policy decision-making lies in their ability to compare relative (not just absolute) risks of various policies, which are less affected by the earth system model uncertainties. Given the uncertainties in forecasts, it is also clear that

  10. The MIT IGSM-CAM framework for uncertainty studies in global and regional climate change

    NASA Astrophysics Data System (ADS)

    Monier, E.; Scott, J. R.; Sokolov, A. P.; Forest, C. E.; Schlosser, C. A.

    2011-12-01

    The MIT Integrated Global System Model (IGSM) version 2.3 is an intermediate complexity fully coupled earth system model that allows simulation of critical feedbacks among its various components, including the atmosphere, ocean, land, urban processes and human activities. A fundamental feature of the IGSM2.3 is the ability to modify its climate parameters: climate sensitivity, net aerosol forcing and ocean heat uptake rate. As such, the IGSM2.3 provides an efficient tool for generating probabilistic distribution functions of climate parameters using optimal fingerprint diagnostics. A limitation of the IGSM2.3 is its zonal-mean atmosphere model that does not permit regional climate studies. For this reason, the MIT IGSM2.3 was linked to the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM) version 3 and new modules were developed and implemented in CAM in order to modify its climate sensitivity and net aerosol forcing to match that of the IGSM. The IGSM-CAM provides an efficient and innovative framework to study regional climate change where climate parameters can be modified to span the range of uncertainty and various emissions scenarios can be tested. This paper presents results from the cloud radiative adjustment method used to modify CAM's climate sensitivity. We also show results from 21st century simulations based on two emissions scenarios (a median "business as usual" scenario where no policy is implemented after 2012 and a policy scenario where greenhouse-gas are stabilized at 660 ppm CO2-equivalent concentrations by 2100) and three sets of climate parameters. The three values of climate sensitivity chosen are median and the bounds of the 90% probability interval of the probability distribution obtained by comparing the observed 20th century climate change with simulations by the IGSM with a wide range of climate parameters values. The associated aerosol forcing values were chosen to ensure a good agreement of the simulations

  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. 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.

  13. Das Universum der Sterne. Himmelsbeobachtungen und Streifzüge durch die moderne Astronomie.

    NASA Astrophysics Data System (ADS)

    Rowan-Robinson, M.

    This book is a German translation, by M. Röser, of the English original published in 1990 (see 52.003.046). Contents: 1. Der Halleysche Komet. 2. Alpha Centauri - Der sonnennächste Stern. 3. Sirius und sein Begleiter, ein Weißer Zwerg. 4. Polaris - Der Polarstern. 5. Wega - Ein Planetensystem im Entstehen? 6. Mira - Der erste bekannte veränderliche Stern. 7. Der Ring-Nebel - "Todeskampf" eines sonnenähnlichen Sterns. 8. Der Orion-Nebel - Die Geburt neuer Sterne. 9. Delta Cephei - Die Meßlatte des Weltalls. 10. Algol - Der Teufelsstern. 11. Nova Aquilae - Der neue Stern von 1918. 12. Der Krebs-Nebel - Die Supernova des Jahres 1054. 13. Die Hyaden und Plejaden - Sternhaufen. 14. Die Milchstraße - Unsere Galaxis. 15. Die Magellanschen Wolken - Unsere Nachbarn im Weltall. 16. Der Andromeda-Nebel - Zwilling unserer Galaxis. 17. Messier 87 - Eine Radiogalaxie. 18. 3C 273 - Rätselhafter Quasar. 19. Messier 82 - Eine "Starburst"-Galaxie. 20. Der Virgo-Haufen - Ein reicher Galaxienhaufen. 21. Das Universum.

  14. A Preliminary MIT-VLA Snapshot Survey Catalog: 8000 MG/PMN Sources at 4.8/8.4 GHz and 0.''3 Resolution

    NASA Astrophysics Data System (ADS)

    Fletcher, A. B.; Burke, B. F.; Conner, S. R.; Herold, L. K.; Lehar, J.; Winn, J. N.; Hewitt, J. N.; Langston, G. I.; Lawrence, C. R.; Bennett, C. L.

    1999-09-01

    A preliminary catalog of the 1981-1994 MIT-VLA Snapshot Survey for radio-loud gravitational lenses will be made available via anonymous ftp from MIT in June 1999 (ftp zenobia.mit.edu; cd pub/fletcher; get mitvla.readme). This plain text catalog contains detailed information on the VLA positions, flux densities and morphologies of ~ 6200 northern MIT-Greenbank (MG) and ~ 1800 Parkes-MIT-NRAO (PMN) radio sources at 4.8 and 8.4 GHz, and at angular resolutions ranging from 0.2 to 0.4 arcseconds. These sources represent ~ 80% of the entire 15 year MIT-VLA Snapshot Survey effort from 1981 to 1995, and are complementary to MIT's VLA-Magellan Gravitational Lens Survey of ~ 1900 flat-spectrum sources begun last year (see J. Winn et al., 1998, BAAS 30(4), p.1425, with a paper recently submitted to the ApJS). The 4.8 GHz single-dish flux densities of the ~ 8000 MIT-VLA sources range from ~ 70 mJy to ~ 5000 mJy. Though the sample is incomplete, it is consistently representative of the wide variety of source morphologies and spectral indices appearing in the MIT-VLA Snapshot Survey. This preliminary MIT-VLA catalog will be improved and checked before publication. It is meanwhile intended as a general purpose resource for the astronomical community; possible uses include (1) organizing an optical follow-up of known gravitational lens candidates within the sample (see A. Fletcher, 1998, MIT Ph.D. thesis), (2) assembling samples of new compact MG and PMN radio sources requiring further imaging using VLBI, such as compact doubles and position calibrators, (3) estimating the mean growth rate of the kiloparsec-scale extended structures in radio-loud AGN (see A. Fletcher & B. Burke, 1998, BAAS 30(4), p.1249), and (4) providing sub-arcsecond information missing from overlapping radio sky surveys made at lower angular resolution, such as the FIRST, WENSS, NVSS and Molonglo Wide Field Surveys.

  15. Harvard-MIT research program in short-lived radiopharmaceuticals. Final report

    SciTech Connect

    Adelstein, S.J.

    1995-02-01

    The Harvard-MIT Research Program in Short-lived Radiopharmaceuticals was established in 1977 to foster interaction among groups working in radiopharmaceutical chemistry at Harvard Medical School, the Massachusetts Institute of Technology, and the Massachusetts General Hospital. To this was added a group at The Childrens Hospital. From these collaborations and building upon the special strengths of the participating individuals, laboratories and institutions, it was hoped that original approaches would be found for the design of new, clinically useful, radiolabeled compounds. The original thrust of this proposal included: (a) examination of the coordination chemistry of technetium as a basis for rational radiopharmaceutical design, (b) development of an ultrashort-lived radionuclide generator for the diagnosis of congenital heart disease in newborns, (c) synthesis of receptor-site-directed halopharmaceuticals, (d) improved facile labeling of complex molecules with positron-emitting radionuclides. The authors` 1986 proposal was oriented toward organs and disease, emphasizing radiolabeled agents that delineate specific functions and the distribution of receptors in brain, heart, and tumors. In 1989, they further refined their purposes and focused on two major aims: (a) synthesis and utilization of neutral technetium and rhenium complexes of high specific activity, and (b) development of new approaches to the radiolabeling of proteins, peptides, immunoglobulins, and their fragments. In 1992, the authors amended this proposal to concentrate their efforts on biologically active peptides and proteins for targeted radiodiagnosis and therapy.

  16. Vibratory Loads Reduction Testing of the NASA/Army/MIT Active Twist Rotor

    NASA Technical Reports Server (NTRS)

    Wilbur, Matthew; Mirick, Paul H.; Yeager, William T., Jr.; Langston, Chester W.; Cesnik, Carlos E. S.; Shin, SangJoon

    2001-01-01

    Recent studies have indicated that controlled strain-induced blade twisting can be attained using piezoelectric active fiber composite technology, and that such advancement may provide a mechanism for reduced rotorcraft vibrations and increased rotor performance. In order to validate these findings experimentally, a cooperative effort between the NASA Langley Research Center, the Army Research Laboratory, and the MIT Active Materials and Structures Laboratory has been developed. As a result of this collaboration a four-bladed, aeroelastically-scaled, active-twist model rotor has been designed and fabricated for testing in the heavy gas test medium of the NASA Langley Transonic Dynamics Tunnel. Initial wind tunnel testing has been conducted to assess the impact of active blade twist on both fixed- and rotating-system vibratory loads in forward flight. The active twist control was found to have a pronounced effect on all system loads and was shown to generally offer reductions in fixed-system loads of 60% to 95%, depending upon flight condition, with 1.1 to 1.4 of dynamic blade twist observed. A summary of the systems developed and the vibratory loads reduction results obtained are presented in this paper.

  17. Hover Testing of the NASA/Army/MIT Active Twist Rotor Prototype Blade

    NASA Technical Reports Server (NTRS)

    Wilbur, Matthew L.; Yeager, William T., Jr.; Wilkie, W. Keats; Cesnik, Carlos E. S.; Shin, Sangloon

    2000-01-01

    Helicopter rotor individual blade control promises to provide a mechanism for increased rotor performance and reduced rotorcraft vibrations and noise. Active material methods, such as piezoelectrically actuated trailing-edge flaps and strain-induced rotor blade twisting, provide a means of accomplishing individual blade control without the need for hydraulic power in the rotating system. Recent studies have indicated that controlled strain induced blade twisting can be attained using piezoelectric active fiber composite technology. In order to validate these findings experimentally, a cooperative effort between NASA Langley Research Center, the Army Research Laboratory, and the MIT Active Materials and Structures Laboratory has been developed. As a result of this collaboration an aeroelastically-scaled active-twist model rotor blade has been designed and fabricated for testing in the heavy gas environment of the Langley Transonic Dynamics Tunnel (TDT). The results of hover tests of the active-twist prototype blade are presented in this paper. Comparisons with applicable analytical predictions of active-twist frequency response in hovering flight are also presented.

  18. NASA Education and Public Outreach Initiatives at the MIT Center for Space Research

    NASA Astrophysics Data System (ADS)

    Porro, I. L.

    2003-12-01

    Since its inception in 1999, the EPO office of the MIT Center for Space Research (CSR) has fostered direct participation of local scientists in educational initiatives such as teachers workshops and public tours of the Chandra Operations and Control Center. The role played by the CSR EPO office has grown significantly, thanks to the award of a number of EPO grants associated with the Chandra and HETE missions. In the past year about one-third of the CSR research staff was involved in the office's EPO initiatives: more than 500 K-12 students, about half from underrepresented groups, were included in formal education programs and informal education events attracted an estimated 900 people. Today the mission of the CSR EPO office is focused in two areas: professional development for K-12 science teachers, and educational programs in out-of-school time. To be associated with major NASA research missions is beneficial to our mission in several respects, but provides also specific challenges. We present here some of the strategies and intiatives that we have undertaken to overcome those challenges.

  19. A Truck, a Plasma and a Pickle: On the Road with MIT's Traveling Plasma Lab

    NASA Astrophysics Data System (ADS)

    Thomas, Paul

    2004-11-01

    For the past 12 years MIT's Mr. Magnet community outreach program has brought the excitement of magnetism into New England's local schools. Averaging 60-70 school visits each year, Mr. Magnet has become a popular school assembly choice. Paul Thomas, the program's creator, has recently expanded the program to offer a one-hour lecture on the principles of plasma science, geared toward middle schools and high schools. The behavior of particles of matter and light in a plasma is complex. Rather than attempt to convey a complete understanding of their quantum nature in a single lecture, Paul Thomas focuses on presenting just enough information to excite a student's imagination. Using a glow discharge plasma, an emission spectrometer, and such ubiquitous substances as nail polish remover, local dirt and a pickle, students discover, by experiment, the unique properties of the plasma state. Equal parts teacher and showman, Paul explains the basic science of plasma while engaging students with hands-on experiments. Paul Thomas will showcase some of his plasma experiments ``live on stage.'' He will explain some of the mechanics involved with traveling to schools, and how he succeeds in engaging students in science exploration. His goal is to spark curiosity, which may lead a student to study science in college or pursue science as a career. He hopes also to encourage APS-DPP members who may wish to establish educational outreach programs for their local communities.

  20. Field Measurement-Based System Identification and Dynamic Response Prediction of a Unique MIT Building.

    PubMed

    Cha, Young-Jin; Trocha, Peter; Büyüköztürk, Oral

    2016-01-01

    Tall buildings are ubiquitous in major cities and house the homes and workplaces of many individuals. However, relatively few studies have been carried out to study the dynamic characteristics of tall buildings based on field measurements. In this paper, the dynamic behavior of the Green Building, a unique 21-story tall structure located on the campus of the Massachusetts Institute of Technology (MIT, Cambridge, MA, USA), was characterized and modeled as a simplified lumped-mass beam model (SLMM), using data from a network of accelerometers. The accelerometer network was used to record structural responses due to ambient vibrations, blast loading, and the October 16th 2012 earthquake near Hollis Center (ME, USA). Spectral and signal coherence analysis of the collected data was used to identify natural frequencies, modes, foundation rocking behavior, and structural asymmetries. A relation between foundation rocking and structural natural frequencies was also found. Natural frequencies and structural acceleration from the field measurements were compared with those predicted by the SLMM which was updated by inverse solving based on advanced multiobjective optimization methods using the measured structural responses and found to have good agreement. PMID:27376303

  1. Field Measurement-Based System Identification and Dynamic Response Prediction of a Unique MIT Building

    PubMed Central

    Cha, Young-Jin; Trocha, Peter; Büyüköztürk, Oral

    2016-01-01

    Tall buildings are ubiquitous in major cities and house the homes and workplaces of many individuals. However, relatively few studies have been carried out to study the dynamic characteristics of tall buildings based on field measurements. In this paper, the dynamic behavior of the Green Building, a unique 21-story tall structure located on the campus of the Massachusetts Institute of Technology (MIT, Cambridge, MA, USA), was characterized and modeled as a simplified lumped-mass beam model (SLMM), using data from a network of accelerometers. The accelerometer network was used to record structural responses due to ambient vibrations, blast loading, and the October 16th 2012 earthquake near Hollis Center (ME, USA). Spectral and signal coherence analysis of the collected data was used to identify natural frequencies, modes, foundation rocking behavior, and structural asymmetries. A relation between foundation rocking and structural natural frequencies was also found. Natural frequencies and structural acceleration from the field measurements were compared with those predicted by the SLMM which was updated by inverse solving based on advanced multiobjective optimization methods using the measured structural responses and found to have good agreement. PMID:27376303

  2. > Elektromobilität - Elemente, Herausforderungen, Potenziale

    NASA Astrophysics Data System (ADS)

    Hanselka, Holger; Jöckel, Michael

    Begrenzte Ressourcen, die CO2-Debatte und der Schutz unserer Umwelt sind beherrschende Themen in der öffentlichen Diskussion. Es ist mittlerweile Konsens, dass der effiziente Umgang mit Energie eine der vordringlichsten Herausforderungen der Zukunft darstellt.

  3. Characterization of arginine kinase, anovel allergen of dermatophagoides farinae (Der f 20)

    PubMed Central

    Xing, Peng; Yu, Haiqiong; Li, Meng; Xiao, Xiaojun; Jiang, Congli; Mo, Lihua; Zhang, Min; Yang, Pingchang; Liu, Zhigang

    2015-01-01

    Objective: To characterize a novel allergen, the Dermatophagoides farinae-derived arginine kinase (Der f 20). Methods: The protein of Der f 20 was synthesized by genetic engineering approaches. The allergenicity of Der f 20 was tested by enzyme-linked immunosorbent assay and an airway allergy mouse model. Results: The Der f 20 gene was cloned andpresented in the Gene Bank with an accession number of AAP57094. The Der f 20 is an arginine kinase (AK), whichshowed a close relationship with D. pteronyssinus AK and Aleuroglyphusovatus AK. Western-blot and ELISA studies showed the IgE binding capacity of Der f 20 was 66.7% in the sera from 6 dust mite allergic patients. Immune inhibition assayresults showed the IgE cross-reactivity between Der f 20 and DME (Dust mite extract). Positive responses to Der f 20 were 41.2% as shown by skin prick tests in 17 DME-allergic patients. In vitro experimental results showed that Der f 20 induced Th2 cell differentiation and the expression of T cell Ig mucin domain molecule-4 (TIM4) in DCs. Conclusions; The Der f 20 protein is a novel subtype of thedust mite allergen. PMID:26885278

  4. Expression, purification and characterization of Der f 27, a new allergen from dermatophagoides farinae.

    PubMed

    Lin, Jianli; Li, Meng; Liu, Yulin; Jiang, Congli; Wu, Yulan; Wang, Yuanyuan; Gao, Anjian; Liu, Zhigang; Yang, Pingchang; Liu, Xiaoyu

    2015-01-01

    The house dust mite (HDM), Dermatophagoidesfarinae (D. farina), is one of the most important indoor allergen sources and a major elicitor of allergic asthma; itscharacterization is important in the diagnosis and immunotherapy of mite allergen-relevant diseases. This study aims to characterize a novel allergen, the D. farinae-derived serpin (Der f 27). In this study, the total RNA of D. farinae was extracted, and the Der f 27 gene was cloned and expressed. The allergenicity of recombinant Der f 27 protein was determined by enzyme-linked immunosorbent assay, and Western-blotting with the sera of asthma patients, and skin prick test (SPT) in allergic human subjects. A r-Der f 27 allergic asthma mouse model was established. The cloned Der f 27 gene has been presented at the Gene Bank with an accession number of KM009995. The IgE levels of r-Der f 27 in the serum from r-Der f 27 SPT positive allergic patients were 3 folds more than healthy subjects. The Der f 27 SPT positive ratewas 42.1% in 19 DM-SPT positive patients. Airway hyperresponsiveness, serum specific IgE, and levels of interleukin-4 in the spleen cell culture supernatant were significantly increased in allergic asthma mice sensitized to r-Der f 27. In conclusion, Der f 27 is a new subtype of house mite allergen.

  5. Development of Improved Models, Stochasticity, and Frameworks for the MIT Extensible Air Network Simulation

    NASA Technical Reports Server (NTRS)

    Clarke, John-Paul

    2004-01-01

    MEANS, the MIT Extensible Air Network Simulation, was created in February of 2001, and has been developed with support from NASA Ames since August of 2001. MEANS is a simulation tool which is designed to maximize fidelity without requiring data of such a low level as to preclude easy examination of alternative scenarios. To this end, MEANS is structured in a modular fashion to allow more detailed components to be brought in when desired, and left out when they would only be an impediment. Traditionally, one of the difficulties with high-fidelity models is that they require a level of detail in their data that is difficult to obtain. For analysis of past scenarios, the required data may not have been collected, or may be considered proprietary and thus difficult for independent researchers to obtain. For hypothetical scenarios, generation of the data is sufficiently difficult to be a task in and of itself. Often, simulations designed by a researcher will model exactly one element of the problem well and in detail, while assuming away other parts of the problem which are not of interest or for which data is not available. While these models are useful for working with the task at hand, they are very often not applicable to future problems. The MEAN Simulation attempts to address these problems by using a modular design which provides components of varying fidelity for each aspect of the simulation. This allows for the most accurate model for which data is available to be used. It also provides for easy analysis of sensitivity to data accuracy. This can be particularly useful in the case where accurate data is available for some subset of the situations that are to be considered. Furthermore, the ability to use the same model while examining effects on different parts of a system reduces the time spent learning the simulation, and provides for easier comparisons between changes to different parts of the system.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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

  18. Twilight of the gods: John Henry Mackay's Der Unschuldige.

    PubMed

    Kennedy, H

    1993-01-01

    The writings of the Scotch-German John Henry Mackay are important for the early cultural history of the modern gay movement. This article recalls this unjustly neglected anarchist writer and advocate of man/boy love by tracing his biography and pointing out his contacts with others in the movement. His late novella Der Unschuldige is analyzed to show that Mackay has encoded homosexuality there in a unique and individual way. PMID:8113599

  19. Laboratory tests of IEC DER object models for grid applications.

    SciTech Connect

    Blevins, John D.; Menicucci, David F.; Byrd, Thomas, Jr.; Gonzalez, Sigifredo; Ginn, Jerry W.; Ortiz-Moyet, Juan

    2007-02-01

    This report describes a Cooperative Research and Development Agreement (CRADA) between Salt River Project Agricultural Improvement and Power District (SRP) and Sandia National Laboratories to jointly develop advanced methods of controlling distributed energy resources (DERs) that may be located within SRP distribution systems. The controls must provide a standardized interface to allow plug-and-play capability and should allow utilities to take advantage of advanced capabilities of DERs to provide a value beyond offsetting load power. To do this, Sandia and SRP field-tested the IEC 61850-7-420 DER object model (OM) in a grid environment, with the goal of validating whether the model is robust enough to be used in common utility applications. The diesel generator OM tested was successfully used to accomplish basic genset control and monitoring. However, as presently constituted it does not enable plug-and-play functionality. Suggestions are made of aspects of the standard that need further development and testing. These problems are far from insurmountable and do not imply anything fundamentally unsound or unworkable in the standard.

  20. Messen, Kalibrieren, Eichen in der Radiologie: Prinzipien und Praxis

    NASA Astrophysics Data System (ADS)

    Wagner, Siegfried R.

    Nach einleitender Erläuterung der unterschiedlichen Meßbedingungen in der Strahlentherapie und im Strahlenschutz werden die metrologischen Probleme am Beispiel der Größenkategorie Äquivalentdosis diskutiert. Als spezielle Größen werden effektive Äquivalentdosis und Umgebungs-Äquivalentdosis eingeführt. Es wird gezeigt, wie richtiges Messen durch ein konsistentes System von Bauartanforderungen an Meßgeräte, durch Kalibrieren und durch Eichen gewährleistet werden kann. Die Bedeutung von Meßunsicherheiten und Fehlergrenzen wird erläutert und ihre Auswirkung auf die Interpretation von Meßergebnissen behandelt.Translated AbstractMeasurements, Calibration, Verification in Radiology: Principles and PracticeThe different measuring conditions in radiotherapy and in radiation protection are discussed in the introduction. Then, the metrological problems are discussed exemplarily with the dose equivalent as a category of quantity. Effective dose equivalent and ambient dose equivalent are introduced as special quantities. It is demonstrated, how correct measurements can be secured by a consistent system of instrument pattern requirements, by calibration and verification. The importance of uncertainties of measurements and of error limits is illustrated and their influence on the interpretation of the results of measurements is treated.

  1. 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.

  2. Autolytic activity of human calpain 7 is enhanced by ESCRT-III-related protein IST1 through MIT-MIM interaction.

    PubMed

    Osako, Yohei; Maemoto, Yuki; Tanaka, Ryohei; Suzuki, Hironori; Shibata, Hideki; Maki, Masatoshi

    2010-11-01

    Calpain 7, a mammalian ortholog of yeast Cpl1/Rim13 and fungal PalB, is an atypical calpain that lacks a penta-EF-hand domain. Previously, we reported that a region containing a tandem repeat of microtubule-interacting and transport (MIT) domains in calpain 7 interacts with a subset of endosomal sorting complex required for transport (ESCRT)-III-related proteins, suggesting involvement of calpain 7 in the ESCRT system. Although yeast and fungal calpains are thought to be involved in alkaline adaptation via limited proteolysis of specific transcription factors, proteolytic activity of calpain 7 has not been demonstrated yet. In this study, we investigated the interaction between calpain 7 and a newly reported ESCRT-III family member, increased sodium tolerance-1 (IST1), which possesses two different types of MIT-interacting motifs (MIM1 and MIM2). We found that glutathione-S-transferase (GST)-fused tandem MIT domains of calpain 7 (calpain 7MIT) pulled down FLAG-tagged IST1 expressed in HEK293T cells. Coimmunoprecipitation assays with various deletion or point mutants of epitope-tagged calpain 7 and IST1 revealed that both repetitive MIT domains and MIMs are required for efficient interaction. Direct MIT-MIM binding was confirmed by a pulldown experiment with GST-fused IST1 MIM and purified recombinant calpain 7MIT. Furthermore, we found that the GST-MIM protein enhances the autolysis of purified Strep-tagged monomeric green fluorescent protein (mGFP)-fused calpain 7 (mGFP-calpain 7-Strep). The autolysis was almost completely abolished by 10 mmN-ethylmaleimide but only partially inhibited by 1 mm leupeptin or E-64. The putative catalytic Cys290-substituted mutant (mGFP-calpain 7(C290S)-Strep) showed no autolytic activity. These results demonstrate for the first time that human calpain 7 is proteolytically active, and imply that calpain 7 is activated in the ESCRT system. PMID:20849418

  3. 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.

  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. The MitCHAP-60 disease is due to entropic destabilization of the human mitochondrial Hsp60 oligomer.

    PubMed

    Parnas, Avital; Nadler, Michal; Nisemblat, Shahar; Horovitz, Amnon; Mandel, Hanna; Azem, Abdussalam

    2009-10-01

    The 60-kDa heat shock protein (mHsp60) is a vital cellular complex that mediates the folding of many of the mitochondrial proteins. Its function is executed in cooperation with the co-chaperonin, mHsp10, and requires ATP. Recently, the discovery of a new mHsp60-associated neurodegenerative disorder, MitCHAP-60 disease, has been reported. The disease is caused by a point mutation at position 3 (D3G) of the mature mitochondrial Hsp60 protein, which renders it unable to complement the deletion of the homologous bacterial protein in Escherichia coli (Magen, D., Georgopoulos, C., Bross, P., Ang, D., Segev, Y., Goldsher, D., Nemirovski, A., Shahar, E., Ravid, S., Luder, A., Heno, B., Gershoni-Baruch, R., Skorecki, K., and Mandel, H. (2008) Am. J. Hum. Genet. 83, 30-42). The molecular basis of the MitCHAP-60 disease is still unknown. In this study, we present an in vitro structural and functional analysis of the purified wild-type human mHsp60 and the MitCHAP-60 mutant. We show that the D3G mutation leads to destabilization of the mHsp60 oligomer and causes its disassembly at low protein concentrations. We also show that the mutant protein has impaired protein folding and ATPase activities. An additional mutant that lacks the first three amino acids (N-del), including Asp-3, is similarly impaired in refolding activity. Surprisingly, however, this mutant exhibits profound stabilization of its oligomeric structure. These results suggest that the D3G mutation leads to entropic destabilization of the mHsp60 oligomer, which severely impairs its chaperone function, thereby causing the disease.

  6. Measuring Neutron Spectrum at MIT Research Reactor Utilizing He-3 Bonner Cylinder Approach with an Unfolding Analysis

    NASA Astrophysics Data System (ADS)

    Leder, Alexander; Ricochet Collaboration

    2016-03-01

    The Ricochet experiment seeks to measure Coherent (neutral-current) Elastic Neutrino-Nucleus Scattering (CENNS) using dark matter style detectors placed near a neutrino source, possibly the MIT research reactor (MITR), which offers a high continuous neutrino flux at high energies. Currently, Ricochet is characterizing the backgrounds at MITR. The main background is the neutrons emitted simultaneously from the core. To characterize this background, we wrapped a Bonner cylinder around a 3He thermal neutron detector, whose data was then unfolded to produce a neutron energy spectrum across several orders of magnitude. We discuss the resulting spectrum as well its implications for deploying Ricochet in the future.

  7. Comparative costs of the Mouse Inoculation Test (MIT) and Virus Isolation in Cell Culture (VICC) for use in rabies diagnosis in Brazil.

    PubMed

    Bones, Vanessa C; Gameiro, Augusto H; Castilho, Juliana G; Molento, Carla F M

    2015-05-01

    The decision to use laboratory animals rather than in vitro methods is frequently based on the financial costs involved, so the objective of our study was to compare the costs of performing the Mouse Inoculation Test (MIT) and Virus Isolation in Cell Culture (VICC) for use in rabies diagnosis in Brazil. Based on observations of laboratory routines at the Pasteur Institute, São Paulo, we listed the fixed cost (FC) and variable cost (VC) items necessary to perform both tests. Considering that 200 MITs are equivalent to 350 VICC assays, in terms of facilities and staff-hours needed per month, we calculated, for both tests, the average total cost per sample, the costs of the implementation of the laboratory structure, and the costs of routine use. With regard to absolute values, the total cost was mainly influenced by FC items, as they represented 60% of the cost for the MIT and 86% of the cost for VICC. A sample analysed by the MIT costs around 205% more than one analysed by using VICC. The MIT costs 74% and 406% more than VICC, when implementation costs and routine use per month, respectively, are taken into account. Our results can assist in the resolution of costing disputes that could hinder the replacement of animals for rabies diagnosis in Brazil. The method demonstrated here might also be useful for cost comparisons in other situations where animal use still continues when validated alternatives exist.

  8. First results from the ‘Violin-Mode’ tests on an advanced LIGO suspension at MIT

    NASA Astrophysics Data System (ADS)

    Lockerbie, N. A.; Carbone, L.; Shapiro, B.; Tokmakov, K. V.; Bell, A.; Strain, K. A.

    2011-12-01

    This paper describes the first results from ‘Violin-Mode’ measurements made on the four suspension fibres of a fully suspended 40 kg test mass. These measurements were made at the LIGO lab, Gravitational Wave Observatory test facility, at MIT. Here, an aluminium-alloy (dummy) test mass, simulating an advanced LIGO (Laser Interferometer Gravitational Wave Observatory) test mass/mirror, had been suspended in air from a test suspension by four fused-silica suspension fibres, each measuring 400 µm in diameter × 600 mm long. Violin-Mode measurements were made on these highly tensioned fibres by retrofitting a prototype system of four novel shadow sensors to the test suspension, one per fibre, these sensors having, collectively, a displacement sensitivity of (6.9 ± 1.3) × 10-11 m (rms) Hz-1/2, at 500 Hz, over a measuring span of ±0.1 mm. Violin-Mode fundamental resonances were detected in all four fibres: with frequencies ˜ 485 Hz when the test mass was supported lightly from below, and at ˜500 Hz when it was fully suspended. In the latter case the Violin-Mode detection took place whilst the test mass, together with its suspension fibres, was undergoing relatively large-amplitude ‘pendulum-mode’ motion, at ˜0.6 Hz. This motion was measured to have a peak-peak amplitude at one of the suspension fibres of up to ˜140 µm (35 µm, rms)—the shadow sensors each having subsidiary outputs for monitoring such low-frequency, large amplitude, motion. Under fully suspended conditions, a calibrated Violin-Mode ‘free-oscillation’ amplitude of 430 ± 20 picometres, rms, was measured at 500.875 Hz, in the same suspension fibre which was found to be undergoing, simultaneously, the ˜140 µm peak-peak motion. Over the bandwidth monitored (dc to 3.2 kHz), Violin-Mode harmonics up to the sixth were recorded in an evoked response. It was concluded that the prototype system had demonstrated amply its practical viability as a detector of Violin-Mode resonances in the

  9. The Ashima/MIT Mars GCM and argon in the martian atmosphere

    NASA Astrophysics Data System (ADS)

    Lian, Yuan; Richardson, Mark I.; Newman, Claire E.; Lee, Christopher; Toigo, Anthony D.; Mischna, Michael A.; Campin, Jean-Michel

    2012-04-01

    We investigate the ability of modern general circulation models (GCMs) to simulate transport in the martian atmosphere using measurements of argon as a proxy for the transport processes. Argon provides the simplest measure of transport as it is a noble gas with no sinks or sources on seasonal timescales. Variations in argon result solely from 'freeze distillation', as the atmosphere condenses at the winter poles, and from atmospheric transport. Comparison of all previously published models when rescaled to a common definition of the argon enhancement factor (EF) suggest that models generally do a poor job in predicting the peak enhancement in southern winter over the winter pole - the time when the capability of the model transport approaches are most severely tested. Despite observed peak EF values of ˜6, previously published model predictions peaked at EF values of only 2-3. We introduce a new GCM that provides a better treatment of mass conservation within the dynamical core, includes more sophisticated tracer transport approaches, and utilizes a cube-sphere grid structure thus avoiding the grid-point convergence problem at the pole that exists for most current Mars GCMs. We describe this model - the Ashima Research/Massachusetts Institute of Technology Mars General Circulation Model (Ashima/MIT Mars GCM) and use it to demonstrate the significant sensitivity of peak EF to the choices of transport approach for both tracers and heat. We obtain a peak EF of 4.75 which, while over 50% higher than any prior model, remains well short of the observed value. We show that the polar EF value in winter is primarily determined by the competition between two processes: (1) mean meridional import of lower-latitude air not enriched in argon and (2) the leakage of enriched argon out of the polar column by eddies in the lowest atmospheric levels. We suggest possibilities for improving GCM representation of the CO2 cycle and the general circulation that may further improve the

  10. Mit castor satellite: Design, implementation, and testing of the communication system

    NASA Astrophysics Data System (ADS)

    Babuscia, Alessandra; McCormack, Matthew Michael; Munoz, Michael; Parra, Spencer; Miller, David W.

    2012-12-01

    Cathode Anode Satellite Thruster for Orbital Reposition (CASTOR) is an orbital manoeuvre and transfer micro-satellite bus developed at MIT Space System Laboratory. The technical objective of the mission is achieving 1 km/s of delta-V over a 1 year mission in Low Earth Orbit (LEO). This will be accomplished using a novel electric propulsion system, the Diverging Cusped Field Thruster (DCFT), which enables high efficiency orbital changes of the ESPA-ring class satellite. CASTOR is capable of improving rapid access to space capabilities by providing an orbital transfer platform with a very high performance to mass ratio, thus greatly reducing launch costs and allowing for highly efficient orbital manoeuvre. Furthermore, CASTOR is highly scalable and modular, allowing it to be adapted to a wide range of scales and applications. CASTOR is developed as part of the University Nanosatellite Program (UNP) funded by Air Force Research Laboratory (AFRL). In order to accomplish CASTOR mission objective, a highly optimized, scalable, light weight, and low cost communication system needed to be developed. These constraints imply the development of trade studies to select the final communication system architecture able to maximize the amount of data transmitted, while guaranteeing reliability, redundancy and limited mass, power consumption, and cost. A special attention is also required to guarantee a reliable communication system in cases of tumbling, or in case of strong Doppler shift which is inevitable due to the high delta-V capabilities of the vehicle. In order to accomplish all the mission requirements, different features have been introduced in the design of the communication system for this mission. Specifically, customized patch antennas have been realized, and a customized communication protocol has been designed and implemented. The communication subsystem has been validated through an intense testing campaign which included software tests in the laboratory, hardware

  11. Analyse der Plasmakoma des Kometen P/Halley mittels Bildverarbeitung der Bochumer Photoplatten

    NASA Astrophysics Data System (ADS)

    Voelzke, M. R.

    1993-12-01

    Photographic and photoeletric observations of comet P/Halley's ion gas coma from CO+ at 4250 A were part of the Bochum Halley Monitoring Program, conducted from 1986 February 17, to April 17 at the European Southern Observatory on La Silla (Chile). In this spectral range it is possible to watch the continuous formation, motion and expansion of plasma structures. To observe the morphology of these structures 32 CO+ photos (glass plates) from P/Halley's comet have been analysed. They have a field of view of 28.6 X 28.6 degrees and were obtained from 1986 March 29, to April 17 with exposure times between 20 and 120 minutes. All photos were digitized with a PDS 2020 GM (Photometric Data System) microdensitometer at the Astronomisches Institut der Westfalischen Wilhelms-Universitaet in Muenster (one pixel = 25 X 25 microns approximately 46.88 X 46.88 arcsec). After digitization the data were reduced to relative intensities, and the part with proper calibrations were also converted to absolute intensities, expressed in terms of column densities using the image data systems MIDAS (Munich Image Data Analysis System; ESO - Image Processing Group, 1988) and IHAP (Image Handling And Processing; Middleburg, 1983). With the help of the Stellingwerf-Theta-Minimum-Method (Stellingwerf, 1978) a period of (2.22 +/- 0.09) days result from analysis of structures in the plasma-coma by subtracting subsequent images. The idea behind subtracting subsequent images is that rotation effects are only 10% phenomena on gas distribution. Difference images are than used to supress the static component of the gas cloud. The CO+ column density data (in molecules cm^-2) were compared with the data of CN column density from Schulz (1990) in all common days. The results show that the relations between CO+ and CN in average column density values (N_CO^+/N_CN) are 11.6 for a circular slit with average diameter (Phi) of 6.1 arcminute which corresponds to a distance from the nucleus (rho) equal to 6.3 X

  12. The MIT HEDP Accelerator Facility for education and advanced diagnostics development for OMEGA, Z and the NIF

    NASA Astrophysics Data System (ADS)

    Petrasso, R.; Gatu Johnson, M.; Armstrong, E.; Han, H. W.; Kabadi, N.; Lahmann, B.; Orozco, D.; Rojas Herrera, J.; Sio, H.; Sutcliffe, G.; Frenje, J.; Li, C. K.; Séguin, F. H.; Leeper, R.; Ruiz, C. L.; Sangster, T. C.

    2015-11-01

    The MIT HEDP Accelerator Facility utilizes a 135-keV linear electrostatic ion accelerator, a D-T neutron source and two x-ray sources for development and characterization of nuclear diagnostics for OMEGA, Z, and the NIF. The ion accelerator generates D-D and D-3He fusion products through acceleration of D ions onto a 3He-doped Erbium-Deuteride target. Fusion reaction rates around 106 s-1 are routinely achieved, and fluence and energy of the fusion products have been accurately characterized. The D-T neutron source generates up to 6 × 108 neutrons/s. The two x-ray generators produce spectra with peak energies of 35 keV and 225 keV and maximum dose rates of 0.5 Gy/min and 12 Gy/min, respectively. Diagnostics developed and calibrated at this facility include CR-39 based charged-particle spectrometers, neutron detectors, and the particle Time-Of-Flight (pTOF) and Magnetic PTOF CVD-diamond-based bang time detectors. The accelerator is also a vital tool in the education of graduate and undergraduate students at MIT. This work was supported in part by SNL, DOE, LLE and LLNL.

  13. 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

  14. Schröder Triangles, Paths, and Parallelogram Polyominoes

    NASA Astrophysics Data System (ADS)

    Pergola, Elisa; Sulanke, Robert A.

    1998-05-01

    This paper considers combinatorial interpretations for two triangular recurrence arrays containing the Schröder numbers s_n = 1, 1, 3, 11, 45 197, ... and r_n = 1, 2, 6, 22, 90, 394, ... , for n = 0, 1, 2, .... These interpretations involve the enumeration of constrained lattice paths and bicolored parallelogram polyominoes, called zebras. In addition to two recent inductive constructions of zebras and their associated generating trees, we present two new ones and a bijection between zebras and constrained lattice paths. We use the constructions with generating function methods to count sets of zebras with respect to natural parameters.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. MIT jar test of the natural polymer chitosan with fresh pond water from the Cambridge Water Department, November-December 1992

    SciTech Connect

    Murcott, S.; Harleman, D.R.F.

    1993-01-01

    The purpose of the MIT (Massachusetts Institute of Technology) jar tests of chitosan using CWD (Cambridge Water Department Treatment Plant) water was to demonstrate the effectiveness of chitosan as a coagulant in drinking water applications. The approach was to compare the performance of the natural organic coagulant, chitosan, to the performance of alum and other chemical coagulants in terms of the parameters turbidity, color, pH and alkalinity. Twenty-five jar tests were conducted during November and December, 1992, at Parsons Laboratory, MIT, Cambridge, Massachusetts.

  20. Flexible DER Utility Interface System: Final Report, September 2004--May 2006

    SciTech Connect

    Lynch, J.; John, V.; Danial, S. M.; Benedict, E.; Vihinen, I.; Kroposki, B.; Pink, C.

    2006-08-01

    In an effort to accelerate deployment of Distributed Energy Resources (DER) such as wind, solar, and conventional backup generators to our nation's electrical grid, Northern Power Systems (NPS), the California Energy Commission (CEC), and the National Renewable Energy Laboratory (NREL) collaborated to create a prototype universal interconnect device called the DER Switch.

  1. 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.

  2. Creatio ex zero. Ursprungs-Konzepte in der mathematischen Naturphilosophie des 19. Jahrhunderts.

    NASA Astrophysics Data System (ADS)

    Heuser, M.-L.

    Die Autorin zeigt in ihrem Beitrag, daß Ansätze der heutigen Selbstorganisationstheorien, die diese in Richtung einer vereinheitlichten dynamischen Theorie verallgemeinern wollen, zumindest in konzeptueller Hinsicht, schon in der Mathematik und Naturphilosophie des 19. Jahrhunderts gewisse Vorläufer finden könnten.

  3. Schönheit und andere Provokationen - Eine neue evolutionsbiologische Theorie der Kunst

    NASA Astrophysics Data System (ADS)

    Junker, Thomas

    Die Evolution hat viele spektakuläre Phänomene hervorgebracht - von der Eleganz des Vogelflugs über die gigantischen Körper der Dinosaurier und die farbenprächtige Vielfalt der Korallenriffe bis hin zu ihrem jüngsten Geniestreich - der menschlichen Kunst. Die schönen Künste - Malerei, Bildhauerei und Architektur, Theater, Tanz, Oper und Filmkunst, Musik und Literatur - Produkte der Evolution? Diese Vorstellung mutet vielen Menschen fremd an, aber wie könnte es anders sein? Denn wenn Charles Darwin recht hat, dann sind nicht nur die körperlichen Merkmale der Menschen als Antworten auf die Erfordernisse des Lebens entstanden, sondern auch ihre geistigen Fähigkeiten und Verhaltensweisen. Im Jahr 1859 hatte er auf den letzten Seiten seines berühmten Buches über die Entstehung der Arten eine kühne Prophezeiung gemacht: Durch die Evolutionstheorie werde es "zu einer bemerkenswerten Revolution in der Naturwissenschaft kommen […]. Die Psychologie wird auf die neue Grundlage gestellt, dass jede geistige Kraft und Fähigkeit notwendigerweise durch graduelle Übergänge erworben wird“ (Darwin 1859, S. 484, 488; Junker 2008).

  4. 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.

  5. Der neue Kosmos. Einführung in die Astronomie und Astrophysik

    NASA Astrophysics Data System (ADS)

    Unsöld, Albrecht; Baschek, Bodo

    Der neue Kosmos bietet in überschaubarem Umfang eine zusammenhängende Einführung in das Gesamtgebiet der Astronomie und Astrophysik. Aus den Bereichen: Klassische Astronomie und Planetensystem, Instrumente und Beobachtungsverfahren, Sonne und Sterne, Milchstraße und Galaxien, Kosmologie, Entstehung des Planetensystems, Entwicklung der Erde und des Lebens werden die Beobachtungsmethoden und die Ergebnisse astronomischer Forschung sowie deren theoretische Grundlagen und wechselseitigen Zusammenhänge vermittelt. Die aktualisierte 7. Auflage berücksichtigt den raschen Fortschritt astronomischer Forschung der letzten drei Jahre von unserem Planetensystem und den Entdeckungen zahlreicher Planeten bei anderen Sternen, über die fernsten Galaxien und Quasare bis zur Entwicklung der modernen Kosmologie.

  6. 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

  7. Herschel und die Zukunft der Fern-Infrarot-Astronomie

    NASA Astrophysics Data System (ADS)

    Linz, Hendrik

    2015-06-01

    Schon lange ist die beobachtende Astronomie den engen Grenzen des optisch Sichbaren entwachsen und hat fast alle Bereiche des elektromagnetischen Spektrums für sich dienstbar gemacht. Im sogenannten nahen und mittleren Infrarot (Wellenlängen zwischen 1-30 μm) sowie im Millimeter- und Radio-Regime (Wellenlängen zwischen 1 mm und 10 m) ist die Erdatmosphäre relativ gut durchlässig für elektromagnetische Signale oder hat zumindest eine Vielzahl von spektral begrenzten Transmissionsfenstern, die astronomische Beobachtungen zumindest von höheren Bergen aus möglich machen. Allerdings ist das sogenannte Ferne Infrarot (FIR, 30-300 μm Wellenlänge) von der Erde aus fast völlig unzugänglich für astronomische Beobachtungen. Selbst für die besten Beobachtungsplätze der Erde bleibt die atmosphärische Transmission durch die immense Wasserdampf- Absorption auf ein absolutes Minimum beschränkt. Jedoch erlaubt uns das FIR Zugang zu Informationen, die sehr nützlich sind für die astrophysikalische Forschung und komplementär zu anderen Wellenlängen-Bereichen.

  8. 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

  9. 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)

  10. 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.

  11. Effect of Amino Acid Polymorphisms of House Dust Mite Der p 2 Variants on Allergic Sensitization

    PubMed Central

    Tanyaratsrisakul, Sasipa; Jirapongsananuruk, Orathai; Kulwanich, Bhakkawarat; Hales, Belinda J.; Thomas, Wayne R.

    2016-01-01

    Purpose The sequence variations of the Der p 2 allergen of Dermatophagoides pteronyssinus diverge along 2 pathways with particular amino acid substitutions at positions 40,47,111, and 114. The environmental prevalence and IgE binding to Der p 2 variants differ among regions. To compare IgE binding to Der p 2 variants between sera from Bangkok, Thailand and Perth, Western Australia with different variants and to determine the variant-specificity of antibodies induced by vaccination with recombinant variants. Methods The structures of recombinant variants produced in yeast were compared by circular dichroism and 1-anilinonaphthalene 8-sulfonic acid staining of their lipid-binding cavity. Sera from subjects in Bangkok and Perth where different variants are found were compared by the affinity (IC50) of IgE cross-reactivity to different variants and by direct IgE binding. Mice were immunized with the variants Der p 2.0101 and Der p 2.0110, and their IgG binding to Der p 2.0103, 2.0104, and 2.0109 was measured. Results The secondary structures of the recombinant variants resembled the natural allergen but with differences in ANS binding. The IC50 of Der p 2.0101 required 7-fold higher concentrations to inhibit IgE binding to the high-IgE-binding Der p 2.0104 than for homologous inhibition in sera from Bangkok where it is absent, while in sera from Perth that have both variants the IC50 was the same and low. Reciprocal results were obtained for Der p 2.0110 not found in Perth. Direct binding revealed that Der p 2.0104 was best for detecting IgE in both regions, followed by Der p 2.0101 with binding to other variants showing larger differences. Mouse anti-Der p 2.0101 antibodies had a high affinity of cross-reactivity but bound poorly to other variants. Conclusions The affinity of IgE antibody cross-reactivity, the direct IgE binding, and the specificities of antibodies induced by vaccination show that measures of allergic sensitization and therapeutic strategies could be

  12. The Effect of Multiple Intelligences Theory (MIT)-based Instruction on Attitudes towards the Course, Academic Success, and Permanence of Teaching on the Topic of "Respiratory Systems"

    ERIC Educational Resources Information Center

    Koksal, Mustafa Serdar; Yel, Mustafa

    2007-01-01

    Studies on the effective teaching of biology have been continuously increasing since the 1800s. New teaching approaches have been purposed and tried out along the way. The multiple intelligences theory (MIT)-based approaches which give more importance to individual in educational settings can provide alternatives for meeting this requirement. An…

  13. Van der Waals Epitaxy of Functional Oxide Heterostructures

    NASA Astrophysics Data System (ADS)

    Chu, Ying-Hao

    In the diligent pursuit of low-power consumption, multifunctional, and environmentally friendly electronics, more sophisticated requirements on functional materials are on demand. Recently, the discovery of 2D layered materials has created a revolution to this field. Pioneered by graphene, these new 2D materials exhibit abundant unusual physical phenomena that is undiscovered in bulk forms. These materials are characterized with their layer form and almost pure 2D electronic behavior. The confinement of charge and heat transport at such ultrathin planes offers possibilities to overcome the bottleneck of present device development in thickness limitation, and thus push the technologies into next generation. Van der Waals epitaxy, an epitaxial growth method to combine 2D and 3D materials, is one of current reliable manufacturing processes to fabricate 2D materials by growing these 2D materials epitaxially on 3D materials. Then, transferring the 2D materials to the substrates for practical applications. In the mean time, van der Waals epitaxy has also been used to create free-standing 3D materials by growing 3D materials on 2D materials and then removing them from 2D materials since the interfacial boding between 2D and 3D materials should be weak van der Waals bonds. In this study, we intend to take the same concept, but to integrate a family of functional materials in order to open new avenue to flexible electronics. Due to the interplay of lattice, charge, orbital, and spin degrees of freedom, correlated electrons in oxides generate a rich spectrum of competing phases and physical properties. Recently, lots of studies have suggested that oxide heterostructures provide a powerful route to create and manipulate the degrees of freedom and offer new possibilities for next generation devices, thus create a new playground for researchers to investigate novel physics and the emergence of fascinating states of condensed matter. In this talk, we use a 2D layered material as

  14. Enhancing undergraduate education in aerospace engineering and planetary sciences at MIT through the development of a CubeSat mission

    NASA Astrophysics Data System (ADS)

    Smith, Matthew W.; Miller, David W.; Seager, Sara

    2011-09-01

    CubeSats are a class of nanosatellites that conform to a standardized 10 cm x 10 cm x 10 cm, 1 kg form factor. This miniaturization, along with a standardized deployment device for launch vehicles, allows CubeSats to be launched at low cost by sharing the trip to orbit with other spacecraft. Part of the original motivation for the CubeSat platform was also to allow university students to participate more easily in space technology development and to gain hands-on experience with flight hardware. The Department of Aeronautics and Astronautics along with the Department of Earth, Atmospheric, and Planetary Studies (EAPS) at the Massachusetts Institute of Technology (MIT) recently completed a three semester-long course that uses the development of a CubeSat-based science mission as its core teaching method. Serving as the capstone academic experience for undergraduates, the goal of this class is to design and build a CubeSat spacecraft that serves a relevant science function, such as the detection of exoplanets transiting nearby stars. This project-based approach gives students essential first hand insights into the challenges of balancing science requirements and engineering design. Students are organized into subsystem-specific teams that refine and negotiate requirements, explore the design trade space, perform modeling and simulation, manage interfaces, test subsystems, and finally integrate prototypes and flight hardware. In this work we outline the heritage of capstone design/build classes at MIT, describe the class format in greater detail, and give results on the ability to meet learning objectives using this pedagogical approach.

  15. Characterization of Der f 29, a new allergen from dermatophagoides farinae

    PubMed Central

    Jiang, Congli; Fan, Xiaoqin; Li, Meng; Xing, Peng; Liu, Xiaoyu; Wu, Yulan; Zhang, Min; Yang, Pingchang; Liu, Zhigang

    2015-01-01

    More than 30 allergens have been identified from Dermatophagoides farina (D. farina), which is one of the main species of house dust mites. The mite allergens are an important factor contributing to allergic disease in the world. As the detection and identification of new allergens is critical for the diagnosis or treatment of allergic diseases, we sought to characterize the profilin of D. farina (Der f 29) in this study. The results showed that 21% of allergic patients displayed positive results in skin prick test with recombinant Der f 29 (rDer f 29) as the specific allergen; specific IgE reactivity to rDer f 29 was shown by Western Blot and ELISA. In addition, rDer f 29 induced bone marrow-derived dendritic cells (DC) to produce T cells immunoglobulin domain and mucin domain protein 4 (TIM4). Moreover, an allergic asthma mouse model was established by challenging with rDer f 29. Airway hyperresponsiveness, serum specific IgE, IgG1, eosinophil infiltration in the allergic mice bronchoalveolar lavage fluid, the cytokines interleukin-4 (IL-4) and interferon-γ (INF-γ) from spleen cells were markedly increased; the histology showed severe inflammation in the lung. In conclusion, Der f 29 is identified as a new type of the house dust mite allergen. PMID:26328014

  16. Characterization of Der f 29, a new allergen from dermatophagoides farinae.

    PubMed

    Jiang, Congli; Fan, Xiaoqin; Li, Meng; Xing, Peng; Liu, Xiaoyu; Wu, Yulan; Zhang, Min; Yang, Pingchang; Liu, Zhigang

    2015-01-01

    More than 30 allergens have been identified from Dermatophagoides farina (D. farina), which is one of the main species of house dust mites. The mite allergens are an important factor contributing to allergic disease in the world. As the detection and identification of new allergens is critical for the diagnosis or treatment of allergic diseases, we sought to characterize the profilin of D. farina (Der f 29) in this study. The results showed that 21% of allergic patients displayed positive results in skin prick test with recombinant Der f 29 (rDer f 29) as the specific allergen; specific IgE reactivity to rDer f 29 was shown by Western Blot and ELISA. In addition, rDer f 29 induced bone marrow-derived dendritic cells (DC) to produce T cells immunoglobulin domain and mucin domain protein 4 (TIM4). Moreover, an allergic asthma mouse model was established by challenging with rDer f 29. Airway hyperresponsiveness, serum specific IgE, IgG1, eosinophil infiltration in the allergic mice bronchoalveolar lavage fluid, the cytokines interleukin-4 (IL-4) and interferon-γ (INF-γ) from spleen cells were markedly increased; the histology showed severe inflammation in the lung. In conclusion, Der f 29 is identified as a new type of the house dust mite allergen.

  17. 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

  18. 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

  19. Das singuläre Modell der über der Oberfläche von Kryodielektrikas lokalisierten Elektronenzustände

    NASA Astrophysics Data System (ADS)

    Dorofeyev, O. F.; Lysov, B. A.; Pavlova, O. S.; Ternov, I. M.

    Wir schlagen ein neues Modell zur Beschreibung der in der Nähe der Oberfläche von Kryodielektrika lokalisierten Elektronenzustände vor. Dabei wird die Nichteindeutigkeit der selbstadjungierten Erweiterung des Hamilton-Operators der elektrostatischen Bildkräfte an der flachen Grenze Dielektrikum-Vakuum benutzt. Im Unterschied zum bekannten Modell von Grimes enthält das von uns vorgeschlagene Modell nur einen einzigen phänomenologischen Parameter, den Vermischungswinkel. Es zeigt sich, daß die entsprechende Wahl des Vermischungswinkels es erlaubt, die spektroskopischen Daten von elektrischen Dipolübergängen zwischen den Einteilchen-Elektronenzuständen, die über der Oberfläche flüssigen 4He und 3He sowie festen Wasserstoffe lokalisiert sind, vollständig zu beschreiben.Translated AbstractA Singular Model of Electronic States, Localized over the Surface of Cryogenized DielectricA new model for the description of localized electronic states near the surface of a cryogenized dielectric is proposed. In this model an ambiguity of the self-adjoined extention of the Hamiltonian for the problem of the motion of an electron in the field of the electrostatic image at flat boundary dielectric-vacuum is used. The proposed model, in contrast with the well known model of Grimes, contains as only phenomenological parameter the mixing angle. It is shown that the proper choise of the mixing angle makes it possible to completely account for the spectroscopic data on electric dipole transitions between singleparticle electronic states localized over the surfaces of 4He, 3He and also solid hydrogen.

  20. The architecture of Hamburg-Bergedorf Observatory 1906 - 1912, compared with other observatories (German Title: Die Architektur der Hamburg-Bergedorfer Sternwarte 1906 - 1912 im Vergleich mit anderen Observatorien)

    NASA Astrophysics Data System (ADS)

    Müller, Peter

    The foundation of the astrophysical observatories in Potsdam-Telegrafenberg in 1874, in Meudon near Paris in 1875 and in Mount Hamilton in California in 1875 resulted in a complete change of observatory architecture. Astrometry had become irrelevant; meridian halls, i.e. an exact north-south orientation, were no longer necessary. The location in the centre of a (university) town was disadvantageous, due to vibrations caused by traffic and artificial light at night. New principles were defined: considerable distance (from the city center), secluded and exposed position (on a mountain) and construction of pavilions: inside a park a pavilion was built for each instrument. Other observatories of this type are: Pic du Midi in the French Alps, built as from 1878 as the first permanent observatory in the high mountains; Nice, Mont Gros, (1879); Brussels, Uccle (1883); Edinburgh, Blackford Hill (1892); Heidelberg, Königstuhl (1896); Barcelona, Monte Tibidado (1902). The original Hamburg Observatory was a modest rectangular building near the Millernrtor; in 1833 it became a State institute. As from 1906 erection of a spacious complex in Bergedorf, 20 km northeast of the city center, took place. Except for the unavailable position on a mountain, this complex fulfilled all principles of a modern observatory: in a park pavilion architecture in an elegant neo-baroque style designed by Albert Erbe (architect of the new Hamburger Kunsthalle with cupola). At the Hamburg Observatory the domed structures were cleverly hierarchised leaving an open view to the south. At the beginning astrometry and astrophysics were equally important; there was still a meridian circle. Apart from that, the instruments were manifold: a large refractor 0.60 m (installed by Repsold/Hamburg, 9 m focal length) and a large reflector 1 m (Zeiss/Jena, 3m focal length). Both were the largest instruments of their kind in the German Empire. In addition, there was the Lippert Astrograph on an elegant polar-axis-type mounting, used for astrophotography. In 1931, Bernhard Schmidt developed the Schmidt telescope here, consisting of a special correction plate and a spherical mirror adequate for “coma-free” astrophotography. To this day, it is still used worldwide. In the Second World War Hamburg was severely hit by Anglo-American bombings. Fortunately, the Bergedorf Observatory on the outskirts was spared. In the meantime, many buildings have been repeatedly restored - the entire complex is of high monument value.

  1. The MIT/WHOI Joint Program in Oceanography and Applied Ocean Science and Engineering: An Ongoing Experiment in Graduate Education and the Sverdrup, Johnson and Fleming Influence.

    NASA Astrophysics Data System (ADS)

    Farrington, J. W.

    2002-12-01

    On May 8, 1968 Paul M. Fye, President of Woods Hole Oceanographic Institution and Howard W. Johnson, President of Massachusetts Institute of Oceanography, signed a Memorandum of Agreement of one and one-half pages in which both partner institutions "have each approved the creation of a Joint Graduate Program in Oceanography for which there will be established appropriate graduate degrees to be conferred jointly by the Massachusetts Institute of Technology and Woods Hole Oceanographic Institution." The partnership brought together the MIT experience with formal graduate education in sciences and engineering involving classroom instruction and more traditional academic advising with the less formal one to one "apprenticeship" or European tutorial style of education at WHOI. During the first year the graduate program involved only the physical sciences with the MIT home being in the Earth, Atmospheric and Planetary Sciences Department. Ocean Engineering was added the following year with the MIT home being the Ocean Engineering Department. Biological Oceanography was added in 1970 with the MIT home being the Biology Department. The existing graduate curricula of the home departments at MIT, the inclusion of ocean engineering, and the fact that several of the early program instructors and advisers at WHOI entered oceanography after formal graduate training in more traditional disciplines such as chemistry, geology, physics, biology and mathematics was not conducive to an automatic adoption of the Sverdrup, Johnson and Fleming paradigm of core courses that predominated in other leading graduate programs in oceanography. Despite this caveat, the Sverdrup, Johnson and Fleming paradigm has influenced the learning environment in the Joint Program. Taking into account lessons learned in the process, some suggestions for the future of graduate education in ocean sciences and ocean engineering will be presented.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  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.

  11. [Ernst von der Porten : looking for facts before and after forced emigration].

    PubMed

    Goerig, M; Bruijn, L

    2014-10-01

    The Ernst von der Porten medal has been awarded for many years to exceptional personalities by the Alliance of German Anesthesiologists to honor the outstanding achievements of the physician Ernst von der Porten from Hamburg in the development of anesthesiology as an autonomous discipline Only recent access to hitherto inaccessible documents enabled the reconstruction of his final years. He was persecuted and excluded by the National Socialist (NS) regime due to his Jewish roots and finally forced to emigrate. Records revealed that even in the so-called safe exile, degrading treatment and humiliation continued for Ernst von der Porten and his family. He eventually evaded this situation by committing suicide.

  12. 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.

  13. Vom Urknall zum Zerfall. Die Welt zwischen Anfang und Ende.

    NASA Astrophysics Data System (ADS)

    Fritzsch, H.

    Contents: Der Tanz mit dem Ozean. Galaktische Landkarte. Das Maß der Dinge. Der würfelnde Gott der Quantenphysik. Geheimnisvolle Felder. Materie und Antimaterie. Quarks - Urstoff unserer Welt. Zerfallende Protonen und die Einheit der Physik. Der Zauberofen. Das überschaubare Universum. Das explodierende Universum. Nachhall der Schöpfung. Der achtfache Weg der kosmischen Entwicklung. Das Ende der Welt. Einheit in der Vielfalt. Das geistige Universum. Gott und das absurde Universum.

  14. GEO 600 spitzt die Ohren. Der deutsche Gravitationswellendetektor erreicht seine geplante Empfindlichkeit

    NASA Astrophysics Data System (ADS)

    Borgeest, Ulf

    2005-04-01

    Die Physiker und Astronomen betreiben weltweit fünf große Laserinterferometer zur Messung von Gravitationswellen, darunter GEO 600 bei Hannover. Die hochempfindlichen Detektoren sollen helfen, die energiereichsten Vorgänge im Weltall aufzuklären und fundamentale physikalische Probleme zu lösen. Zur Zeit beginnen die ersten Messungen mit einer Empfindlichkeit, die astronomische Beobachtungen erlaubt.

  15. NetCoDer: A Retransmission Mechanism for WSNs Based on Cooperative Relays and Network Coding.

    PubMed

    Valle, Odilson T; Montez, Carlos; Medeiros de Araujo, Gustavo; Vasques, Francisco; Moraes, Ricardo

    2016-01-01

    Some of the most difficult problems to deal with when using Wireless Sensor Networks (WSNs) are related to the unreliable nature of communication channels. In this context, the use of cooperative diversity techniques and the application of network coding concepts may be promising solutions to improve the communication reliability. In this paper, we propose the NetCoDer scheme to address this problem. Its design is based on merging cooperative diversity techniques and network coding concepts. We evaluate the effectiveness of the NetCoDer scheme through both an experimental setup with real WSN nodes and a simulation assessment, comparing NetCoDer performance against state-of-the-art TDMA-based (Time Division Multiple Access) retransmission techniques: BlockACK, Master/Slave and Redundant TDMA. The obtained results highlight that the proposed NetCoDer scheme clearly improves the network performance when compared with other retransmission techniques. PMID:27258280

  16. 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.

  17. NetCoDer: A Retransmission Mechanism for WSNs Based on Cooperative Relays and Network Coding

    PubMed Central

    Valle, Odilson T.; Montez, Carlos; Medeiros de Araujo, Gustavo; Vasques, Francisco; Moraes, Ricardo

    2016-01-01

    Some of the most difficult problems to deal with when using Wireless Sensor Networks (WSNs) are related to the unreliable nature of communication channels. In this context, the use of cooperative diversity techniques and the application of network coding concepts may be promising solutions to improve the communication reliability. In this paper, we propose the NetCoDer scheme to address this problem. Its design is based on merging cooperative diversity techniques and network coding concepts. We evaluate the effectiveness of the NetCoDer scheme through both an experimental setup with real WSN nodes and a simulation assessment, comparing NetCoDer performance against state-of-the-art TDMA-based (Time Division Multiple Access) retransmission techniques: BlockACK, Master/Slave and Redundant TDMA. The obtained results highlight that the proposed NetCoDer scheme clearly improves the network performance when compared with other retransmission techniques. PMID:27258280

  18. Der Physik-Nobelpreis vor 100 Jahren Die Entdeckung des trägen Gases

    NASA Astrophysics Data System (ADS)

    Jacobi, Manfred

    2004-11-01

    Im Jahr 1904 erhielt der britische Physiker Lord Rayleigh (John William Strutt, 1842 bis 1919) den Nobelpreis für seine Untersuchungen über die Dichte von Gasen und die Entdeckung des Edelgases Argon.

  19. Optimizing Distributed Energy Resources and building retrofits with the strategic DER-CAModel

    DOE PAGES

    Stadler, M.; Groissböck, M.; Cardoso, G.; Marnay, C.

    2014-08-05

    The pressuring need to reduce the import of fossil fuels as well as the need to dramatically reduce CO2 emissions in Europe motivated the European Commission (EC) to implement several regulations directed to building owners. Most of these regulations focus on increasing the number of energy efficient buildings, both new and retrofitted, since retrofits play an important role in energy efficiency. Overall, this initiative results from the realization that buildings will have a significant impact in fulfilling the 20/20/20-goals of reducing the greenhouse gas emissions by 20%, increasing energy efficiency by 20%, and increasing the share of renewables to 20%,more » all by 2020. The Distributed Energy Resources Customer Adoption Model (DER-CAM) is an optimization tool used to support DER investment decisions, typically by minimizing total annual costs or CO2 emissions while providing energy services to a given building or microgrid site. This document shows enhancements made to DER-CAM to consider building retrofit measures along with DER investment options. Specifically, building shell improvement options have been added to DER-CAM as alternative or complementary options to investments in other DER such as PV, solar thermal, combined heat and power, or energy storage. The extension of the mathematical formulation required by the new features introduced in DER-CAM is presented and the resulting model is demonstrated at an Austrian Campus building by comparing DER-CAM results with and without building shell improvement options. Strategic investment results are presented and compared to the observed investment decision at the test site. Results obtained considering building shell improvement options suggest an optimal weighted average U value of about 0.53 W/(m2K) for the test site. This result is approximately 25% higher than what is currently observed in the building, suggesting that the retrofits made in 2002 were not optimal. Furthermore, the results obtained with

  20. Optimizing Distributed Energy Resources and building retrofits with the strategic DER-CAModel

    SciTech Connect

    Stadler, M.; Groissböck, M.; Cardoso, G.; Marnay, C.

    2014-08-05

    The pressuring need to reduce the import of fossil fuels as well as the need to dramatically reduce CO2 emissions in Europe motivated the European Commission (EC) to implement several regulations directed to building owners. Most of these regulations focus on increasing the number of energy efficient buildings, both new and retrofitted, since retrofits play an important role in energy efficiency. Overall, this initiative results from the realization that buildings will have a significant impact in fulfilling the 20/20/20-goals of reducing the greenhouse gas emissions by 20%, increasing energy efficiency by 20%, and increasing the share of renewables to 20%, all by 2020. The Distributed Energy Resources Customer Adoption Model (DER-CAM) is an optimization tool used to support DER investment decisions, typically by minimizing total annual costs or CO2 emissions while providing energy services to a given building or microgrid site. This document shows enhancements made to DER-CAM to consider building retrofit measures along with DER investment options. Specifically, building shell improvement options have been added to DER-CAM as alternative or complementary options to investments in other DER such as PV, solar thermal, combined heat and power, or energy storage. The extension of the mathematical formulation required by the new features introduced in DER-CAM is presented and the resulting model is demonstrated at an Austrian Campus building by comparing DER-CAM results with and without building shell improvement options. Strategic investment results are presented and compared to the observed investment decision at the test site. Results obtained considering building shell improvement options suggest an optimal weighted average U value of about 0.53 W/(m2K) for the test site. This result is approximately 25% higher than what is currently observed in the building, suggesting that the retrofits made in 2002 were not optimal. Furthermore

  1. EPITOPE-BASED VACCINE FOR THE TREATMENT OF DER F 3 ALLERGY.

    PubMed

    Zhan, Xiaodong; Li, Chaopin; Jiang, Yuxing; Li, Na

    2015-12-01

    Introducción: el asma alérgica está causada por la exposición a los ácaros del polvo casero (HDM). Der f 3 se cree que es uno de los principales alérgenos en los ácaros del asma alérgica. El trabajo consistió en identificar las características inmunológicas de la vacuna basada en epítopo-Der f 3 que contienen las células T y las células B. Métodos: se generaron líneas de células T a partir de células mononucleares de sangre periférica de pacientes alérgicos a Der f 3. Tres epítopos de células T y cinco epítopos de células B de Der f 3, que hemos identificado previamente, fueron seleccionados para diseñar un polipéptido (denominados péptidos Der f 3). Construcciones de DNA que codifican estos péptidos Der f 3 se expresaron en Escherichia coli. Las líneas de células T se estimularon con los péptidos y se utilizaron en el ensayo por su capacidad proliferativa y la producción de citoquinas. Resultados: el plásmido pET28a (+) - Der f 3-péptidos se construyó y se expresaron en E. coli BL21, y la proteína de Der f 3-péptidos se purificó y se confirmaron mediante transferencia de Western. Los Der f 3-péptidos fueron reconocidos por los clones de células T procedentes de pacientes alérgicos. Valor SI de Der f 3 grupo y f grupo 3-péptidos Der eran tanto mayor que la del grupo de PBS (P.

  2. Construction of a Der p2-transgenic plant for the alleviation of airway inflammation.

    PubMed

    Lee, C C; Ho, H; Lee, K T; Jeng, S T; Chiang, B L

    2011-09-01

    In clinical therapy, the amount of antigen administered to achieve oral tolerance for allergic diseases is large, and the cost is a major consideration. In this study, we used tobacco plants to develop a large-scale protein production system for allergen-specific immunotherapy, and we investigated the mechanisms of oral tolerance induced by a transgenic plant-derived antigen. We used plants (tobacco leaves) transgenic for the Dermatophagoides pteronyssinus 2 (Der p2) antigen to produce Der p2. Mice received total protein extract from Der p2 orally once per day over 6 days (days 0-2 and days 6-8). Mice were also sensitized and challenged with yeast-derived recombinant Der p2 (rDer p2), after which the mice were examined for airway hyper-responsiveness and airway inflammation. After sensitization and challenge with rDer p2, mice that were fed with total protein extracted from transgenic plants showed decreases in serum Der p2-specific IgE and IgG1 titers, decreased IL-5 and eotaxin levels in bronchial alveolar lavage fluid, and eosinophil infiltration in the airway. In addition, hyper-responsiveness was also decreased in mice that were fed with total protein extracted from transgenic plants, and CD4(+)CD25(+)Foxp3(+) regulatory T cells were significantly increased in mediastinal and mesenteric lymph nodes. Furthermore, splenocytes isolated from transgenic plant protein-fed mice exhibited decreased proliferation and increased IL-10 secretion after stimulation with rDer p2. The data here suggest that allergen-expressing transgenic plants could be used for therapeutic purposes for allergic diseases.

  3. Molekulare Methoden zum Nachweis, zur Quantifizierung und zum Monitoring der Mykotoxinbildung lebensmittelrelevanter Pilze

    NASA Astrophysics Data System (ADS)

    Geisen, Rolf

    Schimmelpilze kommen ubiquitär vor und spielen besonders bei pflanzlichen Lebensmitteln und Rohprodukten eine besondere Rolle als Verderbsorganismen. Es wird geschätzt, dass 20-25 % der jährlichen Produktion an pflanzlichen Produkten durch Schimmelpilze verdorben werden (Smith et al., 1994). Viele der lebensmittelrelevanten Schimmelpilze sind zudem in der Lage, Mykotoxine, toxische Sekundärmetabolite, zu bilden, was das Ausmaß des Problems deutlich macht. Die wichtigsten mykotoxinbildenden Spezies gehören zu den Fusarien (Trichothecene, Fumonisine, Zearalenon), Aspergillen (Aflatoxin, Ochratoxin, Cyclopiazonsäure) und Penicillien (Patulin, Ochratoxin). Für viele Mykotoxine, wie die Aflatoxine, Ochratoxin, Fumonisine und Trichothecene sind Grenzwerte erlassen worden, die die Verkehrsfähigkeit betroffener Produkte regeln. Die Einhaltung der Grenzwerte kann sehr genau durch offizielle chemisch-analytische Methoden, wie HPLC, GC-MS etc. kontrolliert werden. Diese analytischen Methoden sind aber für die Anwendung eines HACCP-Ansatzes zur Kontrolle der Mykotoxinbildung nur bedingt geeignet, da sie Endpunktkontrollen darstellen und nur das über eine längere Zeit gebildete Mykotoxin bestimmen. Sie sagen daher nichts über die biologischen Bedingungen zur Zeit der Bildung durch den Pilz aus.

  4. BOOK REVIEW: Meilensteine der Astronomie - Von Aristoteles bis Hawking

    NASA Astrophysics Data System (ADS)

    Duerbeck, H. W.; Hamel, J.

    2006-12-01

    A writer, more specific a writer on the history of astronomy, might from time to time look at the collected document folders with all the research material and reprints, and might wonder: has this been all? Especially at a time when recycling is in vogue? And, perhaps with a request or an invitation to submit something, he or she might consider re-using the material before its definitive disposal. Well, such are my feelings when I looked at Jurgen Hamel's new book Milestones of Astronomy - From Aristoteles to Hawking . A slight chance for survival of medium-sized publishers like Kosmos is to offer popular books, and a title must attract potential buyers: Aristoteles means the "old" times, and as concerns the "mad scientist" of modern times, Stephen Hawking has by now dethroned Einstein. In 1998, Hamel had published a Geschichte der Astronomie - Von den Anfangen bis zur Gegenwart (History of astronomy, from the beginnings to the present), which, of course, he could not simply copy. This time, he selected some stones from his research areas - milestones, touchstones, stumbling blocks in the long road of astronomical evolution - and put them between the covers of his new book. So let us look at these (mile)stones . The reader is informed about Aristoteles on 2 pages, but his medieval interpreter Johannes de Sacrobosco gets 8 pages! Copernicus' life and achievements are described on 9 pages, closely followed by his devotee and translator Rothmann with 8 pages; Copernicus' contemporary, Peter Apian, however, gets about 13! Bessel's and Herschel's lifes and works are described on well-deserved 13 and 15 pages, while the achievements of the two Lucasian professors, Isaac Newton and Stephen Hawking, are just outlined in a single paragraph! Thus, importance is sometimes inversely proportional to text length... But let us become serious now. Why should an active historian outline, for the hundreth time, the life of Copernicus, while there are so many interesting, and often

  5. Conversion of Der p 23, a New Major House Dust Mite Allergen, into a Hypoallergenic Vaccine

    PubMed Central

    Banerjee, Srinita; Weber, Milena; Blatt, Katharina; Swoboda, Ines; Focke-Tejkl, Margit; Valent, Peter; Valenta, Rudolf; Vrtala, Susanne

    2015-01-01

    Der p 23, a new, major house dust mite (HDM) allergen that is recognized by >70% of HDM-allergic patients, has high allergenic activity and, therefore, must be considered an important component for HDM-specific immunotherapy. We constructed and characterized a hypoallergenic Der p 23 vaccine for HDM immunotherapy. Three nonallergenic peptides from the C-terminal IgE epitope-containing part of Der p 23 (P4, P5) and P6, a mutant peptide containing serines instead of cysteines, were identified. Peptides were fused to the hepatitis B virus–derived PreS domain as recombinant fusion proteins (i.e., PreS-2XP4P5 and PreS-4XP6) that were expressed in Escherichia coli and purified to homogeneity. Compared with Der p 23, PreS-2XP4P5 and PreS-4XP6 showed no relevant IgE reactivity and exhibited considerably reduced allergenic activity in basophil activation tests using blood from HDM-allergic patients. Upon immunization of rabbits, only PreS-2XP4P5 induced high levels of Der p 23–specific IgG Abs that inhibited binding of patients’ IgE to Der p 23, comparable to IgG Abs induced with Der p 23, whereas Abs induced with PreS-4XP6 had only low blocking capacity. Additionally, IgG Abs induced with PreS-2XP4P5 inhibited Der p 23–induced basophil activation comparable to IgG Abs induced with Der p 23. Compared with Der p 23, PreS-2XP4P5 induced lower T cell proliferation but higher levels of the tolerogenic cytokine IL-10 and the Th1 cytokine IFN-γ in PBMCs from HDM-allergic patients, indicating an immunomodulatory capacity of the fusion protein. Therefore, PreS-2XP4P5 represents a promising candidate for immunotherapy of HDM-allergic patients. PMID:24733847

  6. Sub-micrometer aerosol particles in the upper troposphere/lowermost stratosphere as measured by CARIBIC and modeled using the MIT-CAM3 global climate model

    NASA Astrophysics Data System (ADS)

    Ekman, Annica M. L.; Hermann, Markus; Groß, Peter; Heintzenberg, Jost; Kim, Dongchul; Wang, Chien

    2012-06-01

    In this study, we compare modeled (MIT-CAM3) and observed (CARIBIC) sub-micrometer nucleation (N4-12, 4 ≤ d ≤ 12 nm) and Aitken mode (N12, d > 12 nm) particle number concentrations in the upper troposphere and lowermost stratosphere (UT/LMS). Modeled and observed global median N4-12 and N12 agree fairly well (within a factor of two) indicating that the relatively simplified binary H2SO4-H2O nucleation parameterization applied in the model produces reasonable results in the UT/LMS. However, a comparison of the spatiotemporal distribution of sub-micrometer particles displays a number of discrepancies between MIT-CAM3 and CARIBIC data: N4-12is underestimated by the model in the tropics and overestimated in the extra-topics. N12 is in general overestimated by the model, in particular in the tropics and during summer months. The modeled seasonal variability of N4-12 is in poor agreement with CARIBIC data whereas it agrees rather well for N12. Modeled particle frequency distributions are in general narrower than the observed ones. The model biases indicate an insufficient diffusive mixing in MIT-CAM3 and a too large vertical transport of carbonaceous aerosols. The overestimated transport is most likely caused by the constant supersaturation threshold applied in the model for the activation of particles into cloud droplets. The annually constant SO2 emissions in the model may also partly explain the poor representation of the N4-12seasonal cycle. Comparing the MIT-CAM3 with CARIBIC data, it is also clear that care has to be taken regarding the representativeness of the measurement data and the time frequency of the model output.

  7. 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.

  8. 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.

  9. 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

  10. Helmholtz's early empiricism and the Erhaltung der Kraft.

    PubMed

    Jurkowitz, Edward

    2010-01-01

    Hermann Helmholtz has often been understood to have started research under the influence of Kant, and then to have made a transition to a later mature empiricist phase. Without claiming that in 1847 Helmholtz held the same positions that he later espoused, I suggest that already in his 1847 'Uber die Erhaltung der Kraft' one may find important aspects of his later empiricism. I highlight the ways in which, from early on, Helmholtz turned Kant to use in developing an empirical program of inquiry into possible basic natural causes. To that end, I indicate how, throughout his arguments, Helmholtz employed, sometimes explicitly, but often tacitly, an empiricist logic, one that ran contrary to any form of transcendental deduction, and even to all a priori knowledge. Instead of deriving aspects about the ultimate constituents of nature, Helmholtz aimed to define the proper project for physical natural science. The first part of the paper describes the context of discussion in which Helmholtz entered. The bulk of the paper then analyzes Helmholtz's arguments in order to make space between (1) Kantian, and other, deductions of characteristics that must be true of nature and (2) Helmholtz's delineation of empirically determinable characteristics of presumed ultimate elements of nature, ones that he meant to be specified and delimited through future experimental research. The paper highlights that throughout his discussion Helmholtz meant to define the proper project for physical natural science, a project rife with empiricist aspects. PMID:20503777

  11. 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.

  12. 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.

  13. 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.

  14. Helmholtz's early empiricism and the Erhaltung der Kraft.

    PubMed

    Jurkowitz, Edward

    2010-01-01

    Hermann Helmholtz has often been understood to have started research under the influence of Kant, and then to have made a transition to a later mature empiricist phase. Without claiming that in 1847 Helmholtz held the same positions that he later espoused, I suggest that already in his 1847 'Uber die Erhaltung der Kraft' one may find important aspects of his later empiricism. I highlight the ways in which, from early on, Helmholtz turned Kant to use in developing an empirical program of inquiry into possible basic natural causes. To that end, I indicate how, throughout his arguments, Helmholtz employed, sometimes explicitly, but often tacitly, an empiricist logic, one that ran contrary to any form of transcendental deduction, and even to all a priori knowledge. Instead of deriving aspects about the ultimate constituents of nature, Helmholtz aimed to define the proper project for physical natural science. The first part of the paper describes the context of discussion in which Helmholtz entered. The bulk of the paper then analyzes Helmholtz's arguments in order to make space between (1) Kantian, and other, deductions of characteristics that must be true of nature and (2) Helmholtz's delineation of empirically determinable characteristics of presumed ultimate elements of nature, ones that he meant to be specified and delimited through future experimental research. The paper highlights that throughout his discussion Helmholtz meant to define the proper project for physical natural science, a project rife with empiricist aspects.

  15. 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.

  16. Blick in das kalte Weltall. Protosterne, Staubscheiben und schwarze Löcher.

    NASA Astrophysics Data System (ADS)

    Mezger, P. G.

    Contents: 1. Radioastronomie: Ein neues Fenster ins Weltall öffnet sich. Die Entwicklung der Radioastronomie. Vom Anfang der Welt: Der Urknall. Die Milchstraße und ihr infrarotes Bild. Sterne und interstellare Materie. Die Suche nach den Protosternen. Der Zentralbereich der Milchstraße. Im Zentrum der Milchstraße: Ein schwarzes Loch mit einer Akkretionsscheibe? 2. Der Wissenschaftsbetrieb.

  17. Early results from the MIT millimeter and sub-millimeter balloon-borne anisotropy measurement. [of cosmic microwave background radiation

    NASA Technical Reports Server (NTRS)

    Meyer, Stephan S.; Cheng, Edward S.; Page, Lyman A.

    1991-01-01

    The MIT balloon-borne bolometric search for Cosmic Microwave Background Radiation (CMBR) anisotropies places the most stringent constraints to date on fluctuations in the CMBR. Four maps of half of the Northern Hemisphere at 1.8, 1.1, 0.63 and 0.44 mm wavelength, have a beam size of 3.8 deg with a 1 sigma sensitivity of less than 0.1 mK (thermodynamic) per FOV in each of the first two channels. Analysis of the sky map at 1.8 mm wavelength using a likelihood ratio test for galactic latitudes of 15 deg and greater yields a 95 percent confidence level (CL) upper limit on fluctuations of the CMBR at DeltaT/T less than or equal to 1.6 x 10 exp -5 with a statistical power of 92 percent for Gaussian fluctuations at a correlation angle of 13 deg. Between 3 deg and 22 deg, the upper limit for fluctuations is DeltaT/T less than or equal to 4.0 x 10 exp -5 (95 percent CL).

  18. VizieR Online Data Catalog: The MIT-Green Bank 5GHz Survey (Bennett+, 1986-91)

    NASA Astrophysics Data System (ADS)

    Bennett, C. L.; Lawrence, C. R.; Burke, B. F.; Hewitt, J. N.; Mahoney, J.

    1999-04-01

    The MIT-Green Bank 5 GHz survey catalog was produced from four separate surveys with the National Radio Astronomy Observatory (NRAO) 91m transit telescope (Bennett et al., 1986ApJS...61....1B (MG1); Langston et al., 1990ApJS...72..621L (MG2); Griffith et al., 1990ApJS...74..129G (MG3); Griffith et al. 1991ApJS...75..801G (MG4)). The sky coverage of the various surveys is: 00h < RAB < 24h, -00d30'13" < DECB < +19d29'47" for MG1; 04h < RAJ < 21h, +17.0d < DECJ < +39d09' for MG2; 16h30m < RAB < 05h, +17d < DECB < +39d09' for MG3; and 15h30m < RAB < 02h30m, +37.00d < DECB < +50d58'48" for MG4; where RAB and DECB refer to B1950 coordinates, and RAJ and DECJ refer to J2000 coordinates. The catalog contains 20344 sources detected with a signal-to-noise ratio greater than 5 and 3836 possible detections (MG1) with a signal-to-noise ratio less than 5. Spectral indices are computed for MG1 sources also identified in the Texas 365 MHz survey (Douglas et al. 1980), and for MG1-MG4 sources also identified in the NRAO 1400 MHz Survey (Condon and Broderick 1985). (1 data file).

  19. VizieR Online Data Catalog: The MIT-Green Bank 5GHz Survey (Bennett+, 1986-91)

    NASA Astrophysics Data System (ADS)

    Bennett, C. L.; Lawrence, C. R.; Burke, B. F.; Hewitt, J. N.; Mahoney, J.

    2003-08-01

    The MIT-Green Bank 5GHz survey catalog was produced from four separate surveys with the National Radio Astronomy Observatory (NRAO) 91m transit telescope (Bennett et al., 1986ApJS...61....1B (MG1); Langston et al., 1990ApJS...72..621L (MG2); Griffith et al., 1990ApJS...74..129G (MG3); Griffith et al. 1991ApJS...75..801G (MG4)). The sky coverage of the various surveys is: 00h < RAB < 24h, -00d30'13" < DECB < +19d29'47" for MG1; 04h < RAJ < 21h, +17.0d < DECJ < +39d09' for MG2; 16h30m < RAB < 05h, +17d < DECB < +39d09' for MG3; and 15h30m < RAB < 02h30m, +37.00d < DECB < +50d58'48" for MG4; where RAB and DECB refer to B1950 coordinates, and RAJ and DECJ refer to J2000 coordinates. The catalog contains 20344 sources detected with a signal-to-noise ratio greater than 5 and 3836 possible detections (MG1) with a signal-to-noise ratio less than 5. Spectral indices are computed for MG1 sources also identified in the Texas 365MHz survey (Douglas et al. 1980), and for MG1-MG4 sources also identified in the NRAO 1400MHz Survey (Condon and Broderick 1985). (1 data file).

  20. Massachusetts Beryllium Screening Program for Former Workers of Wyman-Gordon, Norton Abrasives, and MIT/Nuclear Metals

    SciTech Connect

    Pepper, L. D.

    2008-05-21

    The overall objective of this project was to provide medical screening to former workers of Wyman-Gordon Company, Norton Abrasives, and MIT/Nuclear Metals (NMI) in order to prevent and minimize the health impact of diseases caused by site related workplace exposures to beryllium. The program was developed in response to a request by the U.S. Department of Energy (DOE) that had been authorized by Congress in Section 3162 of the 1993 Defense Authorization Act, urging the DOE to carry out a program for the identification and ongoing evaluation of current and former DOE employees who are subjected to significant health risks during such employment." This program, funded by the DOE, was an amendment to the medical surveillance program for former DOE workers at the Nevada Test Site (NTS). This program's scope included workers who had worked for organizations that provided beryllium products or materials to the DOE as part of their nuclear weapons program. These organizations have been identified as Beryllium Vendors.

  1. Upgrade of the MIT Linear Electrostatic Ion Accelerator (LEIA) for nuclear diagnostics development for Omega, Z and the NIF.

    PubMed

    Sinenian, N; Manuel, M J-E; Zylstra, A B; Rosenberg, M; Waugh, C J; Rinderknecht, H G; Casey, D T; Sio, H; Ruszczynski, J K; Zhou, L; Gatu Johnson, M; Frenje, J A; Séguin, F H; Li, C K; Petrasso, R D; Ruiz, C L; Leeper, R J

    2012-04-01

    The MIT Linear Electrostatic Ion Accelerator (LEIA) generates DD and D(3)He fusion products for the development of nuclear diagnostics for Omega, Z, and the National Ignition Facility (NIF). Significant improvements to the system in recent years are presented. Fusion reaction rates, as high as 10(7) s(-1) and 10(6) s(-1) for DD and D(3)He, respectively, are now well regulated with a new ion source and electronic gas control system. Charged fusion products are more accurately characterized, which allows for better calibration of existing nuclear diagnostics. In addition, in situ measurements of the on-target beam profile, made with a CCD camera, are used to determine the metrology of the fusion-product source for particle-counting applications. Finally, neutron diagnostics development has been facilitated by detailed Monte Carlo N-Particle Transport (MCNP) modeling of neutrons in the accelerator target chamber, which is used to correct for scattering within the system. These recent improvements have resulted in a versatile platform, which continues to support the existing nuclear diagnostics while simultaneously facilitating the development of new diagnostics in aid of the National Ignition Campaign at the National Ignition Facility.

  2. Effect of Adding a Regenerator to Kornhauser's MIT "Two-Space" (Gas-Spring+Heat Exchanger) Test Rig

    NASA Technical Reports Server (NTRS)

    Ebiana, Asuquo B.; Gidugu, Praveen

    2008-01-01

    This study employed entropy-based second law post-processing analysis to characterize the various thermodynamic losses inside a 3-space solution domain (gas spring+heat exchanger+regenerator) operating under conditions of oscillating pressure and oscillating flow. The 3- space solution domain is adapted from the 2-space solution domain (gas spring+heat exchanger) in Kornhauser's MIT test rig by modifying the heat exchanger space to include a porous regenerator system. A thermal nonequilibrium model which assumes that the regenerator porous matrix and gas average temperatures can differ by several degrees at a given axial location and time during the cycle is employed. An important and primary objective of this study is the development and application of a thermodynamic loss post-processor to characterize the major thermodynamic losses inside the 3-space model. It is anticipated that the experience gained from thermodynamic loss analysis of the simple 3-space model can be extrapolated to more complex systems like the Stirling engine. It is hoped that successful development of loss post-processors will facilitate the improvement of the optimization capability of Stirling engine analysis codes through better understanding of the heat transfer and power losses. It is also anticipated that the incorporation of a successful thermal nonequilibrium model of the regenerator in Stirling engine CFD analysis codes, will improve our ability to accurately model Stirling regenerators relative to current multidimensional thermal-equilibrium porous media models.

  3. mit-o-matic: a comprehensive computational pipeline for clinical evaluation of mitochondrial variations from next-generation sequencing datasets.

    PubMed

    Vellarikkal, Shamsudheen Karuthedath; Dhiman, Heena; Joshi, Kandarp; Hasija, Yasha; Sivasubbu, Sridhar; Scaria, Vinod

    2015-04-01

    The human mitochondrial genome has been reported to have a very high mutation rate as compared with the nuclear genome. A large number of mitochondrial mutations show significant phenotypic association and are involved in a broad spectrum of diseases. In recent years, there has been a remarkable progress in the understanding of mitochondrial genetics. The availability of next-generation sequencing (NGS) technologies have not only reduced sequencing cost by orders of magnitude but has also provided us good quality mitochondrial genome sequences with high coverage, thereby enabling decoding of a number of human mitochondrial diseases. In this study, we report a computational and experimental pipeline to decipher the human mitochondrial DNA variations and examine them for their clinical correlation. As a proof of principle, we also present a clinical study of a patient with Leigh disease and confirmed maternal inheritance of the causative allele. The pipeline is made available as a user-friendly online tool to annotate variants and find haplogroup, disease association, and heteroplasmic sites. The "mit-o-matic" computational pipeline represents a comprehensive cloud-based tool for clinical evaluation of mitochondrial genomic variations from NGS datasets. The tool is freely available at http://genome.igib.res.in/mitomatic/.

  4. Direct analysis of airborne mite allergen (Der f1) in the residential atmosphere by chemifluorescent immunoassay using bioaerosol sampler.

    PubMed

    Miyajima, Kumiko; Suzuki, Yurika; Miki, Daisuke; Arai, Moeka; Arakawa, Takahiro; Shimomura, Hiroji; Shiba, Kiyoko; Mitsubayashi, Kohji

    2014-06-01

    Dermatophagoides farinae allergen (Der f1) is one of the most important indoor allergens associated with allergic diseases in humans. Mite allergen Der f1 is usually associated with particles of high molecular weight; thus, Der f1 is generally present in settled dust. However, a small quantity of Der f1 can be aerosolized and become an airborne component. Until now, a reliable method of detecting airborne Der f1 has not been developed. The aim of this study was to develop a fiber-optic chemifluorescent immunoassay for the detection of airborne Der f1. In this method, the Der f1 concentration measured on the basis of the intensity of fluorescence amplified by an enzymatic reaction between the labeled enzyme by a detection antibody and a fluorescent substrate. The measured Der f1 concentration was in the range from 0.49 to 250 ng/ml and a similar range was found by enzyme-linked immunosorbent assay (ELISA). This method was proved to be highly sensitive to Der f1 compared with other airborne allergens. For the implementation of airborne allergen measurement in a residential environment, a bioaerosol sampler was constructed. The airborne allergen generated by a nebulizer was conveyed to a newly sampler we developed for collecting airborne Der f1. The sampler was composed of polymethyl methacrylate (PMMA) cells for gas/liquid phases and some porous membranes which were sandwiched in between the two phases. Der f1 in air was collected by the sampler and measured using the fiber-optic immunoassay system. The concentration of Der f1 in aerosolized standards was in the range from 0.125 to 2.0 mg/m(3) and the collection rate of the device was approximately 0.2%.

  5. Institute for Science Education. Institut fur die Padagogik der Naturwissenschaften an der Universitat Kiel. IPN Report-in-Brief 11. 3rd Edition.

    ERIC Educational Resources Information Center

    Blansdorf, Klaus, Ed.

    The Institut fur die Padagogik der Naturwissenschaften (IPN) is the research institute for science education, with a national function in the Federal Republic of Germany. The IPN consists of biology education, chemistry education, physics education, educational science, research methodology/statistics, and administration/general services…

  6. Cloning, expression, purification, characterization, crystallization and X-ray crystallographic analysis of recombinant Der f 21 (rDer f 21) from Dermatophagoides farinae.

    PubMed

    Pang, Sze Lei; Ho, Kok Lian; Waterman, Jitka; Teh, Aik Hong; Chew, Fook Tim; Ng, Chyan Leong

    2015-11-01

    Dermatophagoides farinae is one of the major house dust mite (HDM) species that cause allergic diseases. N-terminally His-tagged recombinant Der f 21 (rDer f 21), a group 21 allergen, with the signal peptide truncated was successfully overexpressed in an Escherichia coli expression system. The purified rDer f 21 protein was initially crystallized using the sitting-drop vapour-diffusion method. Well diffracting protein crystals were obtained after optimization of the crystallization conditions using the hanging-drop vapour-diffusion method with a reservoir solution consisting of 0.19 M Tris-HCl pH 8.0, 32% PEG 400 at 293 K. X-ray diffraction data were collected to 1.49 Å resolution using an in-house X-ray source. The crystal belonged to the C-centered monoclinic space group C2, with unit-cell parameters a = 123.46, b = 27.71, c = 90.25 Å, β = 125.84°. The calculated Matthews coefficient (VM) of 2.06 Å(3) Da(-1) suggests that there are two molecules per asymmetric unit, with a solvent content of 40.3%. Despite sharing high sequence identity with Blo t 5 (45%) and Blo t 21 (41%), both of which were determined to be monomeric in solution, size-exclusion chromatography, static light scattering and self-rotation function analysis indicate that rDer f 21 is likely to be a dimeric protein.

  7. Genomic insights into growth and survival of supercritical-CO2 tolerant bacterium MIT0214 under conditions associated with geologic carbon dioxide sequestration

    NASA Astrophysics Data System (ADS)

    Peet, K. C.; Freedman, A. J.; Hernandez, H.; Thompson, J. R.

    2011-12-01

    Carbon capture and storage (CCS) of CO2 has the potential to significantly reduce the emissions of greenhouse gasses associated with fossil fuel combustion. The largest potential for storing captured CO2 in the United Sates is in deep geologic saline formations. Currently, little is known about the effects of CO2 storage on biologically active microbial communities found in the deep earth biosphere. Therefore, to investigate how deep earth microbial communities will be affected by the storage of CO2 we have enriched for a microbial consortium from the saline formation waters of the Frio 2 project site (Texas Gulf Coast) that is capable of growth in nutrient media under a supercritical CO2 headspace (Hernandez, et al). The cultivation of actively growing cells in an environment containing scCO2 is unexpected based on previous experimental evidence of microbial sterilization attributed to the acidic, desiccating, and solvent-like properties of scCO2. We have isolated strain MIT0214 from this supercritical CO2 based enrichment and have sequenced its genome using the Illumina platform followed by de novo assembly of reads and targeted Sanger sequencing to reduce gaps in the draft assembly. The genome of strain MIT0214 is approximately 5,551,062 base pairs with 35% GC-content and is most similar to nonpathogenic Bacillus cereus strain ATCC 14597. Annotation of the draft assembly of the MIT0214 genome by the Rapid Annotation using Subsystem Technology (RAST) server revealed 5538 coding sequences where 4145 of the coding sequences were assigned putative functions. These functions were enriched in cell wall and capsule formation, phage/prophage and plasmids, gene regulation and signaling, and nitrogen and sulfur metabolism relative to the genome of the most closely-related surface-isolated B. cereus reference (ATCC 14597) and in total 773,416 bp of the MIT0214 genome content was distinct from the B. cereus reference. Notably, this set of distinct sequences were most

  8. 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.

  9. 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

  10. Der p 5 Crystal Structure Provides Insight into the Group 5 Dust Mite Allergens

    SciTech Connect

    Mueller, G.; Gosavi, R; Krahn, J; Edwards, L; Cuneo, M; Glesner, J; Pomes, A; Chapman, M; London, R; Pedersen, L

    2010-01-01

    Group 5 allergens from house dust mites elicit strong IgE antibody binding in mite-allergic patients. The structure of Der p 5 was determined by x-ray crystallography to better understand the IgE epitopes, to investigate the biologic function in mites, and to compare with the conflicting published Blo t 5 structures, designated 2JMH and 2JRK in the Protein Data Bank. Der p 5 is a three-helical bundle similar to Blo t 5, but the interactions of the helices are more similar to 2JMH than 2JRK. The crystallographic asymmetric unit contains three dimers of Der p 5 that are not exactly alike. Solution scattering techniques were used to assess the multimeric state of Der p 5 in vitro and showed that the predominant state was monomeric, similar to Blo t 5, but larger multimeric species are also present. In the crystal, the formation of the Der p 5 dimer creates a large hydrophobic cavity of {approx}3000 {angstrom}{sup 3} that could be a ligand-binding site. Many allergens are known to bind hydrophobic ligands, which are thought to stimulate the innate immune system and have adjuvant-like effects on IgE-mediated inflammatory responses.

  11. Der p 1 facilitates transepithelial allergen delivery by disruption of tight junctions.

    PubMed

    Wan, H; Winton, H L; Soeller, C; Tovey, E R; Gruenert, D C; Thompson, P J; Stewart, G A; Taylor, G W; Garrod, D R; Cannell, M B; Robinson, C

    1999-07-01

    House dust mite (HDM) allergens are important factors in the increasing prevalence of asthma. The lung epithelium forms a barrier that allergens must cross before they can cause sensitization. However, the mechanisms involved are unknown. Here we show that the cysteine proteinase allergen Der p 1 from fecal pellets of the HDM Dermatophagoides pteronyssinus causes disruption of intercellular tight junctions (TJs), which are the principal components of the epithelial paracellular permeability barrier. In confluent airway epithelial cells, Der p 1 led to cleavage of the TJ adhesion protein occludin. Cleavage was attenuated by antipain, but not by inhibitors of serine, aspartic, or matrix metalloproteinases. Putative Der p 1 cleavage sites were found in peptides from an extracellular domain of occludin and in the TJ adhesion protein claudin-1. TJ breakdown nonspecifically increased epithelial permeability, allowing Der p 1 to cross the epithelial barrier. Thus, transepithelial movement of Der p 1 to dendritic antigen-presenting cells via the paracellular pathway may be promoted by the allergen's own proteolytic activity. These results suggest that opening of TJs by environmental proteinases may be the initial step in the development of asthma to a variety of allergens.

  12. 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.

  13. BOOK REVIEW: Meilensteine der Astronomie - Von Aristoteles bis Hawking

    NASA Astrophysics Data System (ADS)

    Duerbeck, H. W.; Hamel, J.

    2006-12-01

    A writer, more specific a writer on the history of astronomy, might from time to time look at the collected document folders with all the research material and reprints, and might wonder: has this been all? Especially at a time when recycling is in vogue? And, perhaps with a request or an invitation to submit something, he or she might consider re-using the material before its definitive disposal. Well, such are my feelings when I looked at Jurgen Hamel's new book Milestones of Astronomy - From Aristoteles to Hawking . A slight chance for survival of medium-sized publishers like Kosmos is to offer popular books, and a title must attract potential buyers: Aristoteles means the "old" times, and as concerns the "mad scientist" of modern times, Stephen Hawking has by now dethroned Einstein. In 1998, Hamel had published a Geschichte der Astronomie - Von den Anfangen bis zur Gegenwart (History of astronomy, from the beginnings to the present), which, of course, he could not simply copy. This time, he selected some stones from his research areas - milestones, touchstones, stumbling blocks in the long road of astronomical evolution - and put them between the covers of his new book. So let us look at these (mile)stones . The reader is informed about Aristoteles on 2 pages, but his medieval interpreter Johannes de Sacrobosco gets 8 pages! Copernicus' life and achievements are described on 9 pages, closely followed by his devotee and translator Rothmann with 8 pages; Copernicus' contemporary, Peter Apian, however, gets about 13! Bessel's and Herschel's lifes and works are described on well-deserved 13 and 15 pages, while the achievements of the two Lucasian professors, Isaac Newton and Stephen Hawking, are just outlined in a single paragraph! Thus, importance is sometimes inversely proportional to text length... But let us become serious now. Why should an active historian outline, for the hundreth time, the life of Copernicus, while there are so many interesting, and often

  14. Molecular, Structural and Immunological Characterization of Der p 18, a Chitinase-Like House Dust Mite Allergen

    PubMed Central

    Resch, Yvonne; Blatt, Katharina; Malkus, Ursula; Fercher, Christian; Swoboda, Ines; Focke-Tejkl, Margit; Chen, Kuan-Wei; Seiberler, Susanne; Mittermann, Irene; Lupinek, Christian; Rodriguez-Dominguez, Azahara; Zieglmayer, Petra; Zieglmayer, René; Keller, Walter; Krzyzanek, Vladislav; Valent, Peter; Valenta, Rudolf; Vrtala, Susanne

    2016-01-01

    Background The house dust mite (HDM) allergen Der p 18 belongs to the glycoside hydrolase family 18 chitinases. The relevance of Der p 18 for house dust mite allergic patients has only been partly investigated. Objective To perform a detailed characterization of Der p 18 on a molecular, structural and immunological level. Methods Der p 18 was expressed in E. coli, purified to homogeneity, tested for chitin-binding activity and its secondary structure was analyzed by circular dichroism. Der p 18-specific IgG antibodies were produced in rabbits to localize the allergen in mites using immunogold electron microscopy and to search for cross-reactive allergens in other allergen sources (i.e. mites, crustacea, mollusca and insects). IgE reactivity of rDer p 18 was tested with sera from clinically well characterized HDM-allergic patients (n = 98) and its allergenic activity was analyzed in basophil activation experiments. Results Recombinant Der p 18 was expressed and purified as a folded, biologically active protein. It shows weak chitin-binding activity and partial cross-reactivity with Der f 18 from D. farinae but not with proteins from the other tested allergen sources. The allergen was mainly localized in the peritrophic matrix of the HDM gut and to a lower extent in fecal pellets. Der p 18 reacted with IgE from 10% of mite allergic patients from Austria and showed allergenic activity when tested for basophil activation in Der p 18-sensitized patients. Conclusion Der p 18 is a rather genus-specific minor allergen with weak chitin-binding activity but exhibits allergenic activity and therefore should be included in diagnostic test panels for HDM allergy. PMID:27548813

  15. VizieR Online Data Catalog: MGIV (Fourth MIT-Green Bank) 5GHz Survey (Griffith+ 1991)

    NASA Astrophysics Data System (ADS)

    Griffith, M.; Langston, G.; Heflin, M.; Conner, S.; Burke, B.

    1998-10-01

    The MIT-Green Bank IV (MG IV) 5 GHz survey covers 0.504 sr of sky in the right ascension range 15.5 to 2.5 hours, between +37.00 and +50.98 degrees declination (B1950). The final MG IV catalog contains 3427 sources detected with a signal-to-noise ratio greater than 5. The catalog was produced from two separate north and south surveys with the National Radio Astronomy Observatory (NRAO) 91m transit telescope. The north survey was produced from data collected while scanning the telescope north from +39.0 to +50.98 degrees declination and the south survey from data collected from scans from +48.98 to +37.00 degrees declination. The completeness and reliability of the final source list is checked by examination of north and south source lists in a twice observed comparison region, lying between +39.15 and +48.83 degrees declination and excluding the area between +/-10 degrees Galactic latitude. The comparison region covers 0.270 sr of sky and contains 1094 sources. In this region, the MG IV catalog contains 423 sources brighter than 90 mJy and is shown to be 99.1 +/- 1.2% complete at this flux density level. Spectral indices are computed for sources identified in the NRAO 1400 MHz Survey (published by Condon and Broderick in 1985). A comparison of the spectral index distributions between +/- 10 and outside of +/- 10 degrees Galactic latitude is presented. (1 data file).

  16. Arzt und Hobby-Astronom in stürmischen Zeiten Der Büchernachlass des Doktor Johannes Häringshauser, Viertelsmedicus in Mistelbach (1630-1641) in der Melker Stiftsbibliothek.

    NASA Astrophysics Data System (ADS)

    Davison, Giles; Glaßner, Gottfried

    2009-06-01

    Auf der Suche nach astronomischer Literatur stieß Giles Davison in der Melker Stiftsbibliothek auf den Namen "Doctor Johannes Häringshauser“ als Besitzer seltener und interessanter astronomischer Werke u.a. von Johannes Regiomontan, Georg von Peuerbach, Michael Mästlin, Johannes Kepler und Daniel Sennert. Weitere in den Jahren 2007-2009 durchgeführte Nachforschungen ergaben, dass es sich um den von 1630-1641 in Mistelbach, Niederösterreich, als Landschaftsarzt tätigen Vater des Melker Konventualen und Bibliothekars Sigismund Häringshauser (1631-1698) handelt. Er wurde 1603 als Sohn des aus Magdeburg stammenden Apothekers Johannes Häringshauser geboren und starb 1642 in Mistelbach. Johannes Häringshauser Sen. bekleidete von 1613-1640 eine Reihe wichtiger Ämter in der Wiener Stadtregierung und starb 1647. Der Studienaufenthalt von Dr. Johannes Häringshauser Jun. in Padua (1624-1626) dürfte das Interesse für Astronomie geweckt haben, das sich in seiner in die Bestände der Melker Stiftsbibliothek eingegangenen Privatbibliothek widerspiegelt. Der Großteil der 10 dem Fachbereich der Astronomie und Astrologie zuzuweisenden Titel wurde von ihm in den Jahren 1636 und 1637 erworben.

  17. Die Pugwash Conferences on Science and World Affairs Ein Beispiel für erfolgreiche „Track-II-Diplomacy“ der Naturwissenschaftler im Kalten Krieg

    NASA Astrophysics Data System (ADS)

    Neuneck, Götz

    "Kein Zeitalter der Geschichte ist stärker von den Naturwissenschaften durchdrungen und abhängiger von ihnen als das 20. Jahrhundert" schreibt Eric Hobsbawn im Kapitel "Zauberer und Lehrlinge: Die Naturwissenschaften" seines Buches "Zeitalter der Extreme".

  18. Photovoltaic DER System Could Save USPS $25,000 per Year in Marina del Rey, California

    SciTech Connect

    Not Available

    2002-11-01

    In numerous projects, government agencies are demonstrating the economic and environmental value of using distributed energy resources (DER) to provide reliable electricity for Federal facilities. These projects also show how renewable DER systems such as photovoltaics (PV) can be effectively integrated into utility power grids to provide added power during peak demand periods in populous regions and states. This four-page case study describes a recent project in which the United States Postal Service (USPS) worked with the U.S. Department of Energy (DOE) Federal Energy Management Program (FEMP), a national laboratory, the local utility, and a private company to install a PV DER system at the USPS Marina Processing and Distribution Center in Inglewood, California. This system is expected to shave 10% off the facility's 1.2-megawatt peak power demand and save more $25,000 per year in utility costs.

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. Amerikas Einschätzung der deutschen Atomforschung: Das deutsche Uranprojekt

    NASA Astrophysics Data System (ADS)

    Walker, Mark

    2002-07-01

    Die amerikanischen Wissenschaftler und ihre emigrierten Kollegen, die am Bau der Atombombe beteiligt waren, verfügten über sehr widersprüchliche und großteils falsche Informationen über den Fortschritt des deutschen Uranprogramms. Noch nach Kriegsende lässt sich dies an Aussagen des Leiters der amerikanischen Alsos-Mission, Samuel Goudsmit, festmachen. Tatsächlich war das deutsche Programm hinsichtlich seiner wissenschaftlichen Grundlagen und des Managements nicht so unterlegen, wie vielfach behauptet wurde. Aber die deutschen Behörden waren nicht in der Lage, Geld und Ressourcen in gleichem Maße in das Uranprojekt zu investieren, wie etwa in das Peenemünder Raketenprojekt.

  5. 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

  6. Renaturierung von Salzgrasländern bzw. Salzwiesen der Küsten

    NASA Astrophysics Data System (ADS)

    Seiberling, Stefan; Stock, Martin

    Die deutschen Meeresküsten werden im übergang vom Land zum Meer weitgehend von zwei ökosystemtypen geprägt. Auf die augenfälligeren, die Dünen, gehen wir hier nicht ein (siehe v. a.Grootjans et al. 2001, 2002, Rozé und Lemauviel 2004, Ketner-Oostra et al. 2006, Aptroot et al. 2007, Bossuyt et al. 2007). Gegenstand dieses Kapitels sind vielmehr die Salzwiesen, die im Wattenmeer der Nordsee als natürlicher Lebensraum auftreten und an der Ostseeküste — hier werden sie Salzgrasländer genannt — zu den ältesten Bestandteilen der Kulturlandschaft zählen. Naturnahe Küstensalzwiesen sind nicht nur Lebensraum für speziell angepasste Pflanzenund Tierarten, sondern tragen auch zur Regulation des marinen Stoffhaushalts und zum Küstenschutz bei.

  7. 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.

  8. Expression and refolding of mite allergen pro-Der f1 from inclusion bodies in Escherichia coli.

    PubMed

    Ling, Chunfang; Zhang, Junyan; Chen, Huifang; Zou, Zehong; Lai, He; Zhang, Jianguo; Lin, Deqiu; Tao, Ailin

    2015-05-01

    House dust mite (Dermatophagoides farinae) allergen Der f1 is one of the most important indoor allergens associated with asthma, eczema and allergic rhinitis in humans. Therefore, sufficient quantities of Der f1 cysteine protease to be used for both experimental and therapeutic purposes are very much needed. Using recombinant DNA technology, high expression rates of cysteine proteases were obtained. The cDNA sequence encoding pro-Der f1 was cloned and expressed in Escherichia coli using the T7 based expression vector pET-44a and induced by isopropyl-β-d-thiogalactoside at a final concentration of 0.2mM. Recombinant pro-Der f1 (pro-rDer f1) was expressed as an inclusion body and the isolated protease was solubilized, refolded and purified. The protease activities and IgE reactivities of pro-rDer f1 that were refolded by size-exclusion chromatography (SEC) were higher than those obtained by dilution. The pair of pro-rDer f1 polypeptides produced by this method could be used for more effective and safer allergen-specific immunotherapy or to produce enzymatically and immunologically active Der f1 for diagnostic testing and deciphering of immunotherapy mechanisms.

  9. 49 CFR 40.215 - What information about the DER do employers have to provide to BATs and STTs?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... to provide to BATs and STTs? 40.215 Section 40.215 Transportation Office of the Secretary of... Personnel § 40.215 What information about the DER do employers have to provide to BATs and STTs? As an employer, you must provide to the STTs and BATs the name and telephone number of the appropriate DER (and...

  10. 49 CFR 40.215 - What information about the DER do employers have to provide to BATs and STTs?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... to provide to BATs and STTs? 40.215 Section 40.215 Transportation Office of the Secretary of... Personnel § 40.215 What information about the DER do employers have to provide to BATs and STTs? As an employer, you must provide to the STTs and BATs the name and telephone number of the appropriate DER (and...

  11. 49 CFR 40.215 - What information about the DER do employers have to provide to BATs and STTs?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... to provide to BATs and STTs? 40.215 Section 40.215 Transportation Office of the Secretary of... Personnel § 40.215 What information about the DER do employers have to provide to BATs and STTs? As an employer, you must provide to the STTs and BATs the name and telephone number of the appropriate DER (and...

  12. 49 CFR 40.215 - What information about the DER do employers have to provide to BATs and STTs?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... to provide to BATs and STTs? 40.215 Section 40.215 Transportation Office of the Secretary of... Personnel § 40.215 What information about the DER do employers have to provide to BATs and STTs? As an employer, you must provide to the STTs and BATs the name and telephone number of the appropriate DER (and...

  13. 49 CFR 40.215 - What information about the DER do employers have to provide to BATs and STTs?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... to provide to BATs and STTs? 40.215 Section 40.215 Transportation Office of the Secretary of... Personnel § 40.215 What information about the DER do employers have to provide to BATs and STTs? As an employer, you must provide to the STTs and BATs the name and telephone number of the appropriate DER (and...

  14. Der p 11 Is a Major Allergen for House Dust Mite-Allergic Patients Suffering from Atopic Dermatitis

    PubMed Central

    Banerjee, Srinita; Resch, Yvonne; Chen, Kuan-Wei; Swoboda, Ines; Focke-Tejkl, Margit; Blatt, Katharina; Novak, Natalija; Wickman, Magnus; van Hage, Marianne; Ferrara, Rosetta; Mari, Adriano; Purohit, Ashok; Pauli, Gabrielle; Sibanda, Elopy N.; Ndlovu, Portia; Thomas, Wayne R.; Krzyzanek, Vladislav; Tacke, Sebastian; Malkus, Ursula; Valent, Peter; Valenta, Rudolf; Vrtala, Susanne

    2015-01-01

    House dust mites (HDMs) belong to the most potent indoor allergen sources worldwide and are associated with allergic manifestations in the respiratory tract and the skin. Here we studied the importance of the high-molecular-weight group 11 allergen from Dermatophagoides pteronyssinus (Der p 11) in HDM allergy. Sequence analysis showed that Der p 11 has high homology to paramyosins from mites, ticks, and other invertebrates. A synthetic gene coding for Der p 11 was expressed in Escherichia coli and rDer p 11 purified to homogeneity as folded, alpha-helical protein as determined by circular dichroism spectroscopy. Using antibodies raised against rDer p 11 and immunogold electron microscopy, the allergen was localized in the muscle beneath the skin of mite bodies but not in feces. IgE reactivity of rDer p 11 was tested with sera from HDM-allergic patients from Europe and Africa in radioallergosorbent test–based dot-blot assays. Interestingly, we found that Der p 11 is a major allergen for patients suffering from atopic dermatitis (AD), whereas it is only a minor allergen for patients suffering from respiratory forms of HDM allergy. Thus, rDer p 11 might be a useful serological marker allergen for the identification of a subgroup of HDM-allergic patients suffering from HDM-associated AD. PMID:24999597

  15. Evolution und Kreationismus im Schulunterricht aus Sicht Großbritanniens. Ist Evolution eine Sache der Akzeptanz oder des Glaubens?

    NASA Astrophysics Data System (ADS)

    Williams, James D.

    Ist Kreationismus eine Weltanschauung oder eine falsche Vorstellung? Ausgehend vom Standpunkt der Naturwissenschaft ist der Unterschied wichtig. Falsche Vorstellungen können herausgefordert und durch gründliche wissenschaftliche Lehre korrigiert werden. Weltanschauungen sind Teil eines etablierten Glaubenssystems, und diese Überzeugungen sind von Natur aus schwer zu verändern (Cohen 1992).

  16. Schule in der Transformation--Transformation der Schule? Was man aus Gesprachen mit ehemaligen Schulern uber die Schule "zwischen zwei Diktaturen" erfahren kann (Schools in Transitions--Transformation of the School? What Can Be Learnt from Former Students Who Experienced Schooling under Two Dictatorial Regimes).

    ERIC Educational Resources Information Center

    Kluchert, Gerhard; Leschinsky, Achim

    1998-01-01

    Addresses interviews that focused on former students' educations under two dictatorial regimes. All the interviewees took their school-leaving examinations between 1951 and 1954. Explains that the interviews are evaluated according to the preconditions, limits, and mechanisms of the school's influence on children and adolescents. (CMK)

  17. Efficacies of immunotherapy with polypeptide vaccine from ProDer f 1 in asthmatic mice

    PubMed Central

    Li, Chaopin; Li, Qiuyu; Jiang, Yuxin

    2015-01-01

    Allergic asthma is associated with the major house dust mite group 1 allergens Der p 1 and Der f 1, which belongs to the papin-like protease family and is the most potent of indoor allergens and allergen-specific immunotherapy (SIT), is seen as effective intervention for the entity. The current study was designed to verify the SIT efficacies of the enzymatic hydrolysates (papain and trypsin) in mice with asthma. We initially developed the asthmatic mouse models with ProDer f 1, and respectively applied recombinant ProDer f 1 protein and the two kinds of enzymatic hydrolysates for SIT. The results were verified by measuring the contents of IL-4, IL-10, IL-17 and IFN-γ changed in both bronchoalveolar lavage fluid (BALF) and supernatant of splenocyte culture as well as level changes of specific IgE and IgG2a in the serum. After SIT intervention, the symptoms of allergic inflammation was alleviated significantly in mice treated with ProDer f 1 protein and the two enzymatic hydrolysates via detection of the lung tissue sections, and infiltration of inflammatory cells was also notably depressed as compared with the models, though the epithelial structure in airways remained similar with the PBS group. In addition, we observed lower serum contents of the specific IgE antibody and lower levels of IL-4, IL-17 in BALF and splenic cells in mice undergone SIT, whereas specific IgG2a, IFN-γ and IL-10 in BALF and supernatant of splenocyte culture were higher as compared to the asthma group. The findings suggest the SIT using the above two kinds of hydrolysates may effectively inhibit the allergic inflammation in the airways of mouse models sensitized with ProDer f 1 protein. PMID:25932130

  18. 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.

  19. 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.

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

    PubMed

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

    2016-09-14

    We demonstrate near-unity, broadband absorbing optoelectronic devices using sub-15 nm thick transition metal dichalcogenides (TMDCs) of molybdenum and tungsten as van der Waals semiconductor active layers. Specifically, we report that near-unity light absorption is possible in extremely thin (<15 nm) van der Waals semiconductor structures by coupling to strongly damped optical modes of semiconductor/metal heterostructures. We further fabricate Schottky junction devices using these highly absorbing heterostructures and characterize their optoelectronic performance. Our work addresses one of the key criteria to enable TMDCs as potential candidates to achieve high optoelectronic efficiency. PMID:27563733

  1. Discriminating between Lüders and von Neumann measuring devices: An NMR investigation

    NASA Astrophysics Data System (ADS)

    Sudheer Kumar, C. S.; Shukla, Abhishek; Mahesh, T. S.

    2016-10-01

    Quantum state after measuring a degenerate observable is given by Lüders and von Neumann state update rules. While the former preserves superpositions, the latter does not. Even though both rules are valid and realizable, which rule a given measuring device ("Black Box") obeys, depends on its internal details. Recently Hegerfeldt and Mayato (2012) [5] had formulated a protocol to discriminate between the two kinds of measuring devices. Here we have reformulated this protocol for system and measuring qubits. We then experimentally investigated this protocol on an NMR spectrometer, and found that Lüders rule is favoured.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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…

  9. Connecting Distributed Energy Resources to the Grid: Their Benefits to the DER Owner etc.

    SciTech Connect

    Poore, WP

    2003-07-09

    The vision of the Distributed Energy Research Program (DER) program of the U.S. Department of Energy (DOE) is that the United States will have the cleanest and most efficient and reliable energy system in the world by maximizing the use of affordable distributed energy resources. Electricity consumers will be able to choose from a diverse number of efficient, cost-effective, and environmentally friendly distributed energy options and easily connect them into the nation's energy infrastructure while providing benefits to their owners and other stakeholders. The long-term goal of this vision is that DER will achieve a 20% share of new electric capacity additions in the United States by 2010, thereby helping to make the nation's electric power generation and delivery system more efficient, reliable, secure, clean, economical, and diverse in terms of fuel use (oil, natural gas, solar, hydroelectric, etc.) and prime mover resource (solar, wind, gas turbines, etc.). Near- and mid-term goals are to develop new technologies for implementing and operating DER and address barriers associated with DER usage and then to reduce costs and emissions and improve the efficiency and reliability of DER. Numerous strategies for meeting these goals have been developed into a research, development, and demonstration (RD&D) program that supports generation and delivery systems architecture, including modeling and simulation tools. The benefits associated with DER installations are often significant and numerous. They almost always provide tangible economic benefits, such as energy savings or transmission and distribution upgrade deferrals, as well as intangible benefits, such as power quality improvements that lengthen maintenance or repair intervals for power equipment. Also, the benefits routinely are dispersed among end users, utilities, and the public. For instance, an end user may use the DER to reduce their peak demand and save money due to lower demand charges. Reduced end user

  10. Bridging the Gap: A Literacy-Oriented Approach to Teaching the Graphic Novel "Der erste Fruhling"

    ERIC Educational Resources Information Center

    Bridges, Elizabeth

    2009-01-01

    This article examines the phenomenon of graphic novels generally, and in particular, their utility in second-language contexts via the example of the graphic adaptation of Klaus Kordoris "Der erste Fruhling." This text lends itself especially to bridging thematic gaps in 20th-century German literature courses, as well as the "language/literature…

  11. 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).

  12. 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.

  13. 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)

  14. 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.

  15. Read the Book or Watch the Movie? "Der Richter und sein Henker" at the Intermediate Level.

    ERIC Educational Resources Information Center

    Hamilton, Elizabeth C.

    2002-01-01

    Examines the debate over the text or media that best enable second-year learners of German to increase their active vocabulary. Suggests the novel "Der Richter und sein Henker" can be enriched by the film adaptation. Classroom tested activities incorporate care fully-sequenced visuals and culminate in analysis of both the book and the film. Sample…

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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…

  3. 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.

  4. 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.

  5. Characterization of a new subtype of allergen in dermatophagoides farinae—Der f 28

    PubMed Central

    Lin, Jian-Li; Wang, Yuan-Yuan; Xiao, Xiao-Jun; Wu, Yu-Lan; Sun, Bao-Qing; Gao, An-Jian; Liu, Zhi-Gang

    2015-01-01

    Background House dust mites (HDMs) are the major sources of indoor allergens which induce asthma, dermatitis, rhinitis, and some other allergic diseases. Close to 30 sub-allergens have been identified. Methods Through analyzing the full genome sequence of dust mite, a new allergen whose primary structure belongs to the heat shock protein family was identified. The sequence of this allergen was determined by cDNA cloning. The allergenicity was assayed by skin prick test, Western-blot and enzyme-linked immunosorbent assay (ELISA). Results r-Der f 28 bound to serum IgE from mite allergic patients. Positive responses to r-Der f 28 were shown in 11.5% by skin prick testing from 26 DM-allergic patients. Airway hyperresponsiveness, serum specific IgE and IL-4 were significantly increased in allergic asthma mouse model sensitized to r-Der f 28. Conclusions Der f 28 is a new subtype of allergen in dermatophagoides farinae. PMID:26623108

  6. Von Tondern nach Gotha. Der Astronom Peter Andreas Hansen, 1795 - 1874.

    NASA Astrophysics Data System (ADS)

    Strumpf, M.; Pehlemann, E.; Wolfschmidt, G.

    This companion booklet to an exposition in honor of Peter Andreas Hansen's 200th birthday contains three papers. Contents: 1. Peter Andreas Hansen - Leben und Wirken in Gotha (M. Strumpf). 2. Peter Andreas Hansens wissenschaftliches Werk (E. Pehlemann). 3. Beobachtungsinstrumente der Sternwarte Gotha zur Zeit Hansens (G. Wolfschmidt).

  7. 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.

  8. 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

  9. 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…

  10. „Überholen ohne einzuholen“ Die Entwicklung von Technologien für übermorgen in Kernenergie und Mikroelektronik der DDR

    NASA Astrophysics Data System (ADS)

    Barkleit, Gerhard

    Dem nuklearen Patt zwischen Ostblock und westlichem Staatenbündnis ist es nach weitgehend übereinstimmender Auffassung von Politik und Wissenschaft zu danken, dass der "Kalte Krieg" in der zweiten Hälfte des 20. Jahrhunderts nicht zum weltumfassenden Flächenbrand eskalierte. An der raschen Herstellung dieses Patts waren zwei Dresdner Physiker maßgeblich beteiligt, deren einer im Manhattan-Projekt in den USA gearbeitet hatte und später in England der Spionage für die Sowjetunion und des Verrats des Know-how der Atombombe überführt wurde.

  11. 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

  12. Quantenphysik und Gravitation Äquivalenzprinzip gilt auch für Quantenobjekte

    NASA Astrophysics Data System (ADS)

    Fray, Sebastian; Hänsch, Theodor W.; Weitz, Martin

    2005-03-01

    Gravitationstheorie und die Quantentheorie zu einer gemeinsamen Theorie vereinheitlichen, das ist eines der ungelösten Probleme der modernen Physik. Garchinger und Tübinger Wissenschaftler haben nun das Äquivalenzprinzip, einen Eckstein der Gravitationstheorie, mit der Methode der Atominterferometrie, die sich der quantenmechanischen Natur von Atomen bedient, überprüft.

  13. Assessment of (mu)grid distributed energy resource potential using DER-CAM and GIS

    SciTech Connect

    Edwards, Jennifer L.; Marnay, Chris; Bartholomew, Emily; Ouaglal, Boubekeur; Siddiqui, Afzal S.; LaCommare, Kristina S.H.

    2002-01-01

    This report outlines an approach to assess the local potential for deployment of distributed energy resources (DER), small power-generation installations located close to the point where the energy they produce will be consumed. Although local restraints, such as zoning, building codes, and on-site physical barriers are well-known frustrations to DER deployment, no analysis method has been developed to address them within a broad economic analysis framework. The approach developed here combines established economic optimization techniques embedded in the Distributed Energy Resource Customer Adoption Model (DER-CAM) with a geographic information system (GIS) analysis of local land-use constraint. An example case in the San Diego area is developed from a strictly customer perspective, based on the premise that future development of DER may take the form of microgrids ((mu)Grids) under the control of current utility customers. Beginning with assumptions about which customer combinations h ave complementary energy loads, a GIS was used to locate specific neighborhoods in the San Diego area with promising customer combinations. A detailed energy analysis was conducted for the commercial/residential area chosen covering both electrical and heat energy requirements. Under various scenarios, different combinations of natural gas reciprocating engines were chosen by DER-CAM, ranging in size from 25 kW to 500 kW, often with heat recovery or absorption cooling. These generators typically operate throughout the day and are supplemented by purchased electricity during late-night and early-morning hours, when utility time-of-use prices are lowest. Typical (mu)Grid scenarios displaced about 80 percent of their annual gas heat load through CHP. Self-generation together with absorption cooling dramatically reduce electricity purchases, which usually only occur during nighttime hours.

  14. Effect of the house dust mite allergen Der p 1 on tryptase release from human mast cells.

    PubMed

    Wang, D Q; Shen, Y Y; Xu, J H; Tang, H

    2016-07-14

    This study aimed to investigate the effects of the house dust mite allergen Der p 1 on the secretion of tryptase from the human mast cell line HMC-1. Flow cytometry was used to determine the expression levels of protease-activated receptor-2 (PAR2) on the surface of HMC-1 cells. HMC-1 cells were treated with Der p 1, SLIGRL-NH2 (PAR2 agonist), LRGILS-NH2 (control peptide for PAR2), or Der p 1 + FSLLRY (PAR2 antagonist), and the tryptase levels were measured using enzyme-linked immunosorbent assay. The biological functions of PAR2 were determined using the calcium green indicator, and intracellular calcium fluorescence intensity in the different groups (Der p 1, SLIGRL-NH2, LRGILS- NH2, Der p 1 + FSLLRY, tryptase, tryptase + FSLLRY, or cell culture medium) was detected by laser scanning confocal microscopy. The mast cells expressed PAR2 receptor on their surfaces. Der p 1 alone induced a significant release of intracellular calcium and tryptase in HMC-1 cells compared with the SLIGRL- NH2 treatment group and the control group. The combination of Der p 1 and FSLLRY partly inhibited intracellular calcium and tryptase release in HMC-1 cells compared with the Der p 1 treatment group. Moreover, tryptase induced a significant release of intracellular calcium in the HMC-1 cells. Der p 1 induced HMC-1 cell degranulation and the release of tryptase by activating the PAR2 receptor on the cell surfaces. Tryptase activated the PAR2 receptor and induced intracellular calcium release from the HMC-1 cells in a positive feedback loop.

  15. Effect of the house dust mite allergen Der p 1 on tryptase release from human mast cells.

    PubMed

    Wang, D Q; Shen, Y Y; Xu, J H; Tang, H

    2016-01-01

    This study aimed to investigate the effects of the house dust mite allergen Der p 1 on the secretion of tryptase from the human mast cell line HMC-1. Flow cytometry was used to determine the expression levels of protease-activated receptor-2 (PAR2) on the surface of HMC-1 cells. HMC-1 cells were treated with Der p 1, SLIGRL-NH2 (PAR2 agonist), LRGILS-NH2 (control peptide for PAR2), or Der p 1 + FSLLRY (PAR2 antagonist), and the tryptase levels were measured using enzyme-linked immunosorbent assay. The biological functions of PAR2 were determined using the calcium green indicator, and intracellular calcium fluorescence intensity in the different groups (Der p 1, SLIGRL-NH2, LRGILS- NH2, Der p 1 + FSLLRY, tryptase, tryptase + FSLLRY, or cell culture medium) was detected by laser scanning confocal microscopy. The mast cells expressed PAR2 receptor on their surfaces. Der p 1 alone induced a significant release of intracellular calcium and tryptase in HMC-1 cells compared with the SLIGRL- NH2 treatment group and the control group. The combination of Der p 1 and FSLLRY partly inhibited intracellular calcium and tryptase release in HMC-1 cells compared with the Der p 1 treatment group. Moreover, tryptase induced a significant release of intracellular calcium in the HMC-1 cells. Der p 1 induced HMC-1 cell degranulation and the release of tryptase by activating the PAR2 receptor on the cell surfaces. Tryptase activated the PAR2 receptor and induced intracellular calcium release from the HMC-1 cells in a positive feedback loop. PMID:27421012

  16. 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°.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. Recent KBO (Pluto/Charon and beyond, including Quaoar) Occultation Observations by the Williams College Team as part of the Williams-MIT Collaboration

    NASA Astrophysics Data System (ADS)

    Pasachoff, Jay M.; Babcock, B. A.; Davis, A. B.; Pandey, S.; Lu, M.; Rogosinski, Z.; Person, M. J.; Bosh, A. S.; Zangari, A. M.; Zuluaga, C. A.; Gulbis, A. S.; Naranjo, O.; Navas, G.; Zerpa, L.; Villarreal, J.; Rojo, P.; Förster, F.; Servajean, E.

    2013-10-01

    The Williams College-MIT collaboration has observed numerous occultations of stars by Pluto/Charon and other Kuiper-belt objects (www.stellaroccultations.info), since its establishment three decades ago with an attempted discovery of Neptune's rings in 1983. In this paper, we describe several recent occultation observations, both successful and (for reasons of path uncertainties and/or weather) unsuccessful. Light curves made or arranged by Williams College faculty and students were used together with light curves by MIT colleagues and others to study Pluto's atmosphere and Charon's size, to discover one of the highest-known solar-system albedos (KBO 55636), and to attempt to study 1000-km-diameter Quaoar. Observations discussed include light curves for KBO 55636 on 9 October 2009 from Hawaii; Pluto on 3/4 July 2010 from Chile, 22 May 2011 from Williamstown, Massachusetts, 23 June 2011 from Hawaii (in support of SOFIA observations of Pluto's atmosphere, discussed in an article in press in AJ and of the pair of Pluto/Charon occultations of the same star), and 4 May 2013 (Bosh et al., this conference) and 15 July 2013 from Williamstown; Charon on 15 June 2013 from Williamstown; Quaoar from a picket fence ranging from Chile through Venezuela (with a detection there) to Massachusetts on July 8/9 and in South Africa on 12 July 2013. This work was supported in part by NASA Planetary Astronomy grants NNX08AO50G and NNH11ZDA001N to Williams College, NNX10AB27G to MIT, and USRA grant #8500-98-003 to Lowell Observatory. We thank Steven P. Souza at Williams; Steven Levine at Lowell Obs.; Jennifer G. Winters (GSU) in Chile; Richard Rojas/Jorge Moreno in Venezuela; Scott Sheppard; Federica Bianco; David Osip; and others. ZR (Vassar '14) was a Keck Northeast Astronomy Consortium Summer Fellow at Williams College, supported by an NSF/REU grant to the Keck Northeast Astronomy Consortium. ES: partial support from Programa Nacional de Becas de Postgrado (CONICYT Grant 21110496). FF

  2. Black phosphorene/monolayer transition-metal dichalcogenides as two dimensional van der Waals heterostructures: a first-principles study.

    PubMed

    You, Baiqing; Wang, Xiaocha; Zheng, Zhida; Mi, Wenbo

    2016-03-14

    The electronic structure of black phosphorene (BP)/monolayer 1H-XT2 (X = Mo, W; T = S, Se, Te) two dimensional (2D) van der Waals heterostructures have been calculated by the first-principles method. It is found that the electronic band structures of both BP and XT2 are preserved in the combined van der Waals heterostructures. The WSe2/BP van der Waals heterostructure demonstrates a type-I band alignment, but the MoS2/BP, MoSe2/BP, MoTe2/BP, WS2/BP and WTe2/BP van der Waals heterostructures demonstrate a type-II band alignment. In particular, the n-type XT2/p-type BP van der Waals heterostructures can be applied in p-n diode and logical devices. Strong spin splitting appears in all of the heterostructures when considering the spin orbital coupling. Our results play a significant role in the prediction of novel 2D van der Waals heterostructures that have potential applications in spin-filter devices, spin field effect transistors, optoelectronic devices, etc. PMID:26899350

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Nonlocal van der Waals functionals: the case of rare-gas dimers and solids.

    PubMed

    Tran, Fabien; Hutter, Jürg

    2013-05-28

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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  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. [Heinrich Hoffmann's Der Struwwelpeter (1845/1859): a parody on the romantic cult of childhood].

    PubMed

    Wesseling, Lies

    2006-01-01

    This article analyzes the cultural dynamics of the construction and deconstruction of childhood images, by means of a case study of Heinrich Hoffmann's classic picture book, Der Struwwelpeter (1845/1859). Childhood images are the joint product of sciences (especially anthropology, pedagogy and developmental psychology) and arts (especially painting, photography and (children's) literature). These images are historically variable, because childhood is the permanent target of idealization and demystification. This article interprets Der Struwwelpeter as a demystication of Romantic idealizations of childhood as propounded by Romantic Naturphilosophie and, more specifically, the pedagogy of Friedrich Fröbel (1772-1852). In my view, this picture book satirizes the developmentalism and the pastoryl idyll which informed the Romantic image of childhood, through its verbal and visual components. As I argue at length, this satire directly bears upon leading scientific and political controversies of Hoffmann's time.

  4. 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.

  5. 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.

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

    DOE PAGES

    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. 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

  9. 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.

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  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. PMID:21469648

  16. van der Waals epitaxy and photoresponse of two-dimensional CdSe plates

    NASA Astrophysics Data System (ADS)

    Zhu, Dan-Dan; Xia, Jing; Wang, Lei; Li, Xuan-Ze; Tian, Li-Feng; Meng, Xiang-Min

    2016-06-01

    Here we demonstrate the first growth of two-dimensional (2D) single-crystalline CdSe plates on mica substrates via van der Waals epitaxy. The as-synthesized 2D plates exhibit hexagonal, truncated triangular and triangular shapes with the lateral size around several microns. Photodetectors based on 2D CdSe plates present a fast response time of 24 ms, revealing that 2D CdSe is a promising building block for ultrathin optoelectronic devices.

  17. Epitaxial growth of molecular crystals on van der waals substrates for high-performance organic electronics.

    PubMed

    Lee, Chul-Ho; Schiros, Theanne; Santos, Elton J G; Kim, Bumjung; Yager, Kevin G; Kang, Seok Ju; Lee, Sunwoo; Yu, Jaeeun; Watanabe, Kenji; Taniguchi, Takashi; Hone, James; Kaxiras, Efthimios; Nuckolls, Colin; Kim, Philip

    2014-05-01

    Epitaxial van der Waals (vdW) heterostructures of organic and layered materials are demonstrated to create high-performance organic electronic devices. High-quality rubrene films with large single-crystalline domains are grown on h-BN dielectric layers via vdW epitaxy. In addition, high carrier mobility comparable to free-standing single-crystal counterparts is achieved by forming interfacial electrical contacts with graphene electrodes. PMID:24458727

  18. Assessment of MIT and UCB wall condensation tests and of the pre-release RELAP5/MOD3.2 code condensation models

    SciTech Connect

    Shumway, R.W.

    1995-01-01

    In recent years, a new class of reactor designs has been proposed that utilize passive safety systems. General Electric has developed a Simplified Boiling Water Reactor (SBWR) design that relies on such passive systems. The SBWR has two passive cooling systems that involve energy transfer by condensation. These are the isolation condenser system (ICS) and the passive containment cooling systems (PCCS). It is important that such heat transfer phenomena be correctly understood and quantified. The General Electric Company has sponsored tests at the Massachusetts Institute of Technology (MIT) and at the University of California at Berkeley (UCB) to obtain data simulating PCCS conditions. Data was obtained with pure steam, steam-air mixtures and steam-helium mixtures. INEL has been contracted by the NRC to evaluate these tests and assess existing condensation heat transfer correlations against the test data. This report assesses the relevance of the tests to SBWR conditions and shows RELAP5/MOD3.2 predictions of the tests.

  19. Development of the system for visualization of electric conductivity distribution in human brain and its activity by the magnetic induction tomography (MIT) method

    NASA Astrophysics Data System (ADS)

    Sapetsky, S.; Cherepenin, V.; Korjenevsky, A.; Kornienko, V.; Vartanov, A.

    2010-04-01

    Currently rapid development of functional activity researches of human brain sets the problem of reliable and non-invasive detection of mental processes and states. At present we know some traditional methods of rapid and contactless acquisition of brain activity characteristics, such as functional tomography (fMRI) and magnetoencephalography. But these methods have low temporal resolution, complicated and ambiguous association of measured values with information processes in brain. So possibility of MIT application is investigated. Estimation of possibility of such changes registration is performed. Investigations of magnetic field configuration, schematics of transmit-receive modules and numerical algorithms are in progress. It may allow us to register high speed conductivity changes in brain tissues.

  20. Adjustable impedance, force feedback and command language aids for telerobotics (parts 1-4 of an 8-part MIT progress report)

    NASA Technical Reports Server (NTRS)

    Sheridan, Thomas B.; Raju, G. Jagganath; Buzan, Forrest T.; Yared, Wael; Park, Jong

    1989-01-01

    Projects recently completed or in progress at MIT Man-Machine Systems Laboratory are summarized. (1) A 2-part impedance network model of a single degree of freedom remote manipulation system is presented in which a human operator at the master port interacts with a task object at the slave port in a remote location is presented. (2) The extension of the predictor concept to include force feedback and dynamic modeling of the manipulator and the environment is addressed. (3) A system was constructed to infer intent from the operator's commands and the teleoperation context, and generalize this information to interpret future commands. (4) A command language system is being designed that is robust, easy to learn, and has more natural man-machine communication. A general telerobot problem selected as an important command language context is finding a collision-free path for a robot.