Science.gov

Sample records for zur untersuchung transienter

  1. 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.

  2. Eine selbstkonsistente Carleman Linearisierung zur Analyse von Oszillatoren

    NASA Astrophysics Data System (ADS)

    Weber, Harry; Mathis, Wolfgang

    2017-09-01

    Die Analyse nichtlinearer dynamischer Schaltungen ist bis heute eine herausfordernde Aufgabe, da nur selten analytische Lösungen angegeben werden können. Daher wurden eine Vielzahl von Methoden entwickelt, um eine qualitative oder quantitative Näherung für die Lösungen der Netzwerkgleichung zu erhalten. Oftmals wird beispielsweise eine Kleinsignalanalyse mit Hilfe einer Taylorreihe in einem Arbeitspunkt durchgeführt, die nach den Gliedern erster Ordnung abgebrochen wird. Allerdings ist diese Linearisierung nur in der Nähe des stabilen Arbeitspunktes für hyperbolische Systeme gültig. Besonders für die Analyse des dynamischen Verhaltens von Oszillatoren treten jedoch nicht-hyperbolische Systeme auf, sodass diese Methode nicht angewendet werden kann Mathis (2000). Carleman hat gezeigt, dass nichtlineare Differentialgleichungen mit polynomiellen Nichtlinearitäten in ein unendliches System von linearen Differentialgleichungen transformiert werden können Carleman (1932). Wird das unendlichdimensionale Gleichungssystem für numerische Zwecke abgebrochen, kann bei Oszillatoren der Übergang in eine stationäre Schwingung (Grenzzyklus) nicht wiedergegeben werden. In diesem Beitrag wird eine selbstkonsistente Carleman Linearisierung zur Untersuchung von Oszillatoren vorgestellt, die auch dann anwendbar ist, wenn die Nichtlinearitäten keinen Polynomen entsprechen. Anstelle einer linearen Näherung um einen Arbeitspunkt, erfolgt mit Hilfe der Carleman Linearisierung eine Approximation auf einem vorgegebenen Gebiet. Da es jedoch mit der selbstkonsistenten Technik nicht möglich ist, das stationäre Verhalten von Oszillatoren zu beschreiben, wird die Berechnung einer Poincaré-Abbildung durchgeführt. Mit dieser ist eine anschließende Analyse des Oszillators möglich.

  3. 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.

  4. Digitalisierung in der Energiewirtschaft - empirische Untersuchung und Wertschöpfungskette

    NASA Astrophysics Data System (ADS)

    Dell, Timo

    Die Energiewirtschaft nutzt seit je her digitale Strukturen zur Umsetzung ihrer Prozesse. Durch den (neuen) verabschiedeten politischen Ordnungsrahmen - dem Gesetz zur Digitalisierung der Energiewende - und durch die rasante Fortentwicklung technologischer Strukturen ergeben sich jedoch die Wertschöpfungsstufen erweiternde, diversifizierende und innovative Möglichkeiten für Energieversorger (EVU) Geschäftsfelder auszubauen bzw. neue zu erschließen. Dabei ist die digitale (R)Evolution keine rein technische Umsetzung, sondern insbesondere auch eine unternehmensinterne, strategische und intern-kulturelle Herausforderung.

  5. The Zur regulon of Corynebacterium glutamicum ATCC 13032

    PubMed Central

    2010-01-01

    Background Zinc is considered as an essential element for all living organisms, but it can be toxic at large concentrations. Bacteria therefore tightly regulate zinc metabolism. The Cg2502 protein of Corynebacterium glutamicum was a candidate to control zinc metabolism in this species, since it was classified as metalloregulator of the zinc uptake regulator (Zur) subgroup of the ferric uptake regulator (Fur) family of DNA-binding transcription regulators. Results The cg2502 (zur) gene was deleted in the chromosome of C. glutamicum ATCC 13032 by an allelic exchange procedure to generate the zur-deficient mutant C. glutamicum JS2502. Whole-genome DNA microarray hybridizations and real-time RT-PCR assays comparing the gene expression in C. glutamicum JS2502 with that of the wild-type strain detected 18 genes with enhanced expression in the zur mutant. The expression data were combined with results from cross-genome comparisons of shared regulatory sites, revealing the presence of candidate Zur-binding sites in the mapped promoter regions of five transcription units encoding components of potential zinc ABC-type transporters (cg0041-cg0042/cg0043; cg2911-cg2912-cg2913), a putative secreted protein (cg0040), a putative oxidoreductase (cg0795), and a putative P-loop GTPase of the COG0523 protein family (cg0794). Enhanced transcript levels of the respective genes in C. glutamicum JS2502 were verified by real-time RT-PCR, and complementation of the mutant with a wild-type zur gene reversed the effect of differential gene expression. The zinc-dependent expression of the putative cg0042 and cg2911 operons was detected in vivo with a gfp reporter system. Moreover, the zinc-dependent binding of purified Zur protein to double-stranded 40-mer oligonucleotides containing candidate Zur-binding sites was demonstrated in vitro by DNA band shift assays. Conclusion Whole-genome expression profiling and DNA band shift assays demonstrated that Zur directly represses in a zinc

  6. Transient Ischemic Attack

    Transient Ischemic Attack TIA , or transient ischemic attack, is a "mini stroke" that occurs when a blood ... The only difference between a stroke and TIA is that with TIA the blockage is transient (temporary). ...

  7. Structural and Mechanistic Basis of Zinc Regulation Across the E. coli Zur Regulon

    PubMed Central

    Gilston, Benjamin A.; Wang, Suning; Marcus, Mason D.; Canalizo-Hernández, Mónica A.; Swindell, Elden P.; Xue, Yi; Mondragón, Alfonso; O'Halloran, Thomas V.

    2014-01-01

    Commensal microbes, whether they are beneficial or pathogenic, are sensitive to host processes that starve or swamp the prokaryote with large fluctuations in local zinc concentration. To understand how microorganisms coordinate a dynamic response to changes in zinc availability at the molecular level, we evaluated the molecular mechanism of the zinc-sensing zinc uptake regulator (Zur) protein at each of the known Zur-regulated genes in Escherichia coli. We solved the structure of zinc-loaded Zur bound to the PznuABC promoter and show that this metalloregulatory protein represses gene expression by a highly cooperative binding of two adjacent dimers to essentially encircle the core element of each of the Zur-regulated promoters. Cooperativity in these protein-DNA interactions requires a pair of asymmetric salt bridges between Arg52 and Asp49′ that connect otherwise independent dimers. Analysis of the protein-DNA interface led to the discovery of a new member of the Zur-regulon: pliG. We demonstrate this gene is directly regulated by Zur in a zinc responsive manner. The pliG promoter forms stable complexes with either one or two Zur dimers with significantly less protein-DNA cooperativity than observed at other Zur regulon promoters. Comparison of the in vitro Zur-DNA binding affinity at each of four Zur-regulon promoters reveals ca. 10,000-fold variation Zur-DNA binding constants. The degree of Zur repression observed in vivo by comparison of transcript copy number in wild-type and Δzur strains parallels this trend spanning a 100-fold difference. We conclude that the number of ferric uptake regulator (Fur)-family dimers that bind within any given promoter varies significantly and that the thermodynamic profile of the Zur-DNA interactions directly correlates with the physiological response at different promoters. PMID:25369000

  8. Digitale Transformation, aber wie? - Von der Spielwiese zur Umsetzungsplanung

    NASA Astrophysics Data System (ADS)

    Kaiser, Thomas

    Es besteht wohl kaum Anlass zur Annahme, dass die seit Jahrzehnten etablierten Markt- und Technologiestrukturen der Energiewirtschaft sich nicht in einem radikalen Ablöseprozess mit Gewinnern und Verlierern befinden. Aber Vorsicht - vordergründig bereits verloren erscheinende Geschäftsmodelle erfahren im Zuge der Digitalisierung einerseits noch intensiveren Wettbewerbsdruck, können aber andererseits von diesem "technologischen Jungbrunnen" profitieren, um verlorenes Terrain zurückzugewinnen. Im folgenden Kapitel wird ein Managementzyklus aufgezeigt, der in Anlehnung an die bereits erfolgreiche Implementierung digitaler R/Evolutionen anderer Branchen aufzeigt, wie die Geschäftsleitung systematisch kostenbewusst und zielorientiert die Digitalisierung umsetzen kann.

  9. Terminal Transient Phase of Chaotic Transients

    NASA Astrophysics Data System (ADS)

    Lilienkamp, Thomas; Parlitz, Ulrich

    2018-03-01

    Transient chaos in spatially extended systems can be characterized by the length of the transient phase, which typically grows quickly with the system size (supertransients). For a large class of these systems, the chaotic phase terminates abruptly, without any obvious precursors in commonly used observables. Here we investigate transient spatiotemporal chaos in two different models of this class. By probing the state space using perturbed trajectories we show the existence of a "terminal transient phase," which occurs prior to the abrupt collapse of chaotic dynamics. During this phase the impact of perturbations is significantly different from the earlier transient and particular patterns of (non)susceptible regions in state space occur close to the chaotic trajectories. We therefore hypothesize that even without perturbations proper precursors for the collapse of chaotic transients exist, which might be highly relevant for coping with spatiotemporal chaos in cardiac arrhythmias or brain functionality, for example.

  10. PSH Transient Simulation Modeling

    SciT

    Muljadi, Eduard

    PSH Transient Simulation Modeling presentation from the WPTO FY14 - FY16 Peer Review. Transient effects are an important consideration when designing a PSH system, yet numerical techniques for hydraulic transient analysis still need improvements for adjustable-speed (AS) reversible pump-turbine applications.

  11. Transient ischemic attack

    MedlinePlus

    ... artery surgery - discharge Stroke - discharge Taking warfarin (Coumadin) Images Endarterectomy Transient Ischemic attack (TIA) References Biller J, Ruland S, Schneck MJ. Ischemic cerebrovascular disease. In Daroff ...

  12. Liquid Biopsy zur Überwachung von Melanompatienten.

    PubMed

    Gaiser, Maria Rita; von Bubnoff, Nikolas; Gebhardt, Christoffer; Utikal, Jochen Sven

    2018-04-01

    In den letzten sechs Jahren wurden verschiedene innovative systemische Therapien zur Behandlung des metastasierten malignen Melanoms (MM) entwickelt. Die konventionelle Chemotherapie wurde durch neuartige Primärtherapien abgelöst, darunter systemische Immuntherapien (Anti-CTLA4- und Anti-PD1-Antikörper; Zulassung von Anti-PDL1-Antikörpern erwartet) und Therapien, die gegen bestimmte Mutationen gerichtet sind (BRAF, NRAS und c-KIT). Daher stehen die behandelnden Ärzte neuen Herausforderungen gegenüber, beispielsweise der Stratifizierung von Patienten für geeignete Behandlungen und der Überwachung von Langzeit-Respondern auf Progression. Folglich werden zuverlässige Methoden zur Überwachung von Krankheitsprogression oder Behandlungsresistenz benötigt. Lokalisierte und fortgeschrittene Krebserkrankungen können zur Bildung zirkulierender Tumorzellen und Tumor-DNA (ctDNA) führen, die sich in Proben von peripherem Blut nachweisen und quantifizieren lassen (Liquid Biopsy). Im Fall von Melanompatienten können die Ergebnisse von Liquid Biopsy als neuartige prädiktive Biomarker bei therapeutischen Entscheidungen hilfreich sein, insbesondere im Zusammenhang mit mutationsbasierten zielgerichteten Therapien. Die Herausforderungen bei der Anwendung der Liquid Biopsy beinhalten strikte Kriterien für den Phänotyp der zirkulierenden MM-Zellen oder ihrer Fragmente und die Instabilität von ctDNA im Blut. In diesem Übersichtsartikel diskutieren wir die Beschränkungen der Liquid Biopsy hinsichtlich ihrer Anwendung in der Routinediagnostik. © 2018 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  13. Transient Ischemic Attack

    MedlinePlus

    A transient ischemic attack (TIA) is a stroke that lasts only a few minutes. It happens when the blood supply to part of the brain is briefly blocked. Symptoms of a TIA are like other stroke symptoms, but do not ...

  14. Transient familial hyperbilirubinemia

    MedlinePlus

    ... Babies with this disorder are born with severe jaundice . Causes Transient familial hyperbilirubinemia is an inherited disorder. ... death. Symptoms The newborn may have: Yellow skin (jaundice) Yellow eyes (icterus) Lethargy If untreated, seizures and ...

  15. Transient Global Amnesia

    MedlinePlus

    ... global amnesia is a sudden, temporary episode of memory loss that can't be attributed to a ... know well. But that doesn't make your memory loss less disturbing. Fortunately, transient global amnesia is ...

  16. Transient Astrophysics Observatory (TAO)

    NASA Astrophysics Data System (ADS)

    Racusin, J. L.; TAO Team

    2016-10-01

    The Transient Astrophysics Observatory (TAO) is a NASA MidEx mission concept (formerly known as Lobster) designed to provide simultaneous wide-field gamma-ray, X-ray, and near-infrared observations of the sky.

  17. Transient multivariable sensor evaluation

    SciT

    Vilim, Richard B.; Heifetz, Alexander

    A method and system for performing transient multivariable sensor evaluation. The method and system includes a computer system for identifying a model form, providing training measurement data, generating a basis vector, monitoring system data from sensor, loading the system data in a non-transient memory, performing an estimation to provide desired data and comparing the system data to the desired data and outputting an alarm for a defective sensor.

  18. Gamma ray transients

    NASA Technical Reports Server (NTRS)

    Cline, Thomas L.

    1987-01-01

    The discovery of cosmic gamma ray bursts was made with systems designed at Los Alamos Laboratory for the detection of nuclear explosions beyond the atmosphere. HELIOS-2 was the first gamma ray burst instrument launched; its initial results in 1976, seemed to deepen the mystery around gamma ray transients. Interplanetary spacecraft data were reviewed in terms of explaining the behavior and source of the transients.

  19. The Components of the Unique Zur Regulon of Cupriavidus metallidurans Mediate Cytoplasmic Zinc Handling

    PubMed Central

    Bütof, Lucy; Schmidt-Vogler, Christopher; Herzberg, Martin; Große, Cornelia

    2017-01-01

    ABSTRACT Zinc is an essential trace element, yet it is toxic at high concentrations. In the betaproteobacterium Cupriavidus metallidurans, the highly efficient removal of surplus zinc from the periplasm is responsible for the outstanding metal resistance of the organism. Rather than having a typical Zur-dependent, high-affinity ATP-binding cassette transporter of the ABC protein superfamily for zinc uptake at low concentrations, C. metallidurans has the secondary zinc importer ZupT of the zinc-regulated transporter, iron-regulated transporter (ZRT/IRT)-like protein (ZIP) family. It is important to understand, therefore, how this zinc-resistant bacterium copes with exposure to low zinc concentrations. Members of the Zur regulon in C. metallidurans were identified by comparing the transcriptomes of a Δzur mutant and its parent strain. The consensus sequence of the Zur-binding box was derived for the zupTp promoter-regulatory region by use of a truncation assay. The motif was used to predict possible Zur boxes upstream of Zur regulon members. The binding of Zur to these boxes was confirmed. Two Zur boxes upstream of the cobW1 gene, encoding a putative zinc chaperone, proved to be required for complete repression of cobW1 and its downstream genes in cells cultivated in mineral salts medium. A Zur box upstream of each of zur-cobW2, cobW3, and zupT permitted both low expression levels of these genes and their upregulation under conditions of zinc starvation. This demonstrates a compartmentalization of zinc homeostasis in C. metallidurans, where the periplasm is responsible for the removal of surplus zinc, cytoplasmic components are responsible for the management of zinc as an essential cofactor, and the two compartments are connected by ZupT. IMPORTANCE Elucidating zinc homeostasis is necessary for understanding both host-pathogen interactions and the performance of free-living bacteria in their natural environments. Escherichia coli acquires zinc under conditions of

  20. The components of the unique Zur regulon of Cupriavidus metallidurans mediate cytoplasmic zinc handling.

    PubMed

    Bütof, Lucy; Schmidt-Vogler, Christopher; Herzberg, Martin; Große, Cornelia; Nies, Dietrich H

    2017-08-14

    Zinc is an essential trace element and at the same time it is toxic at high concentrations. In the beta-proteobacterium Cupriavidus metallidurans the highly efficient removal of surplus zinc from the periplasm is responsible for its outstanding metal resistance. Rather than having a typical Zur-dependent, high-affinity ATP-binding cassette transporter of the ABC protein superfamily for zinc uptake at low concentrations, C. metallidurans instead has the secondary zinc importer ZupT of the ZRT/IRT (ZIP) family. It is important to understand, therefore, how this zinc-resistant bacterium copes when it is exposed to low zinc concentrations. Members of the Zur regulon in C. metallidurans were identified by comparing the transcriptomes of a Δ zur mutant and its parent strain. The consensus sequence of the Zur-binding box was derived for the zupTp promoter-regulatory region using a truncation assay. The motif was used to predict possible Zur-boxes upstream of Zur regulon members. Binding of Zur to these boxes was confirmed. Two Zur-boxes upstream of the cobW 1 gene, encoding a putative zinc chaperone, proved to be required for complete repression of cobW 1 and its downstream genes in cells cultivated in mineral salts medium. A Zur box upstream of each of zur-cobW 2 , cobW 3 and zupT permitted low-expression level of these genes plus their up-regulation under zinc starvation conditions. This demonstrates a compartmentalization of zinc homeostasis in C. metallidurans with the periplasm being responsible for removal of surplus zinc and cytoplasmic components for management of zinc as an essential co-factor, with both compartments connected by ZupT. Importance Elucidating zinc homeostasis is necessary to understand both host-pathogen interactions and performance of free-living bacteria in their natural environment. Escherichia coli acquires zinc under low zinc concentrations by the Zur-controlled ZnuABC importer of the ABC superfamily, and this was also the paradigm for other

  1. Variabilität des Reviergesangs des Buchfinken (Fringilla coelebs) zur Raum-Zeit-Beschreibung von Metapopulationen

    NASA Astrophysics Data System (ADS)

    Nolte, Björn

    2003-10-01

    Der Buchfinkengesang wurde in Potsdam in zwei Hauptpopulationen über drei Jahre aufgenommen. Jedes Individuum wurde eindeutig am individuellen Strophentypenrepertoire identifiziert. Ein weiterer Punkt der die individuelle Wiedererkennung bestätigt ist die hohe Standorttreue der adulten Männchen. Die beschriebene Methode eignet sich für die Untersuchung von gesamten Populationen, um den Wandel des Gesangs von Populationen in Raum und Zeit zu beschreiben. Die Haupterkenntnisse der Arbeit sind: - Die Gesamtanzahl der Grundstrophentypen innerhalb einer Population bleibt über Jahre konstant. - Die relative Häufigkeit jedes einzelnen Strophentyps variiert von Jahr zu Jahr und von Population zu Population. - Gesangslernen erfolgt exakt mit einem Korrektheitsgrad von mindestens 96%. - Das Song-Sharing ist innerhalb der Population hoch. Die diskutierten Mechanismen für das Song-Sharing sind: Die Lebenserwartung, das Zugverhalten, das Lernverhalten, die Etabliertheit von Strophentypen, Weibchenpräferenzen und die Reaktionen der territorialen Männchen. - Weiterhin wurde ein Modell zur kulturellen Evolution des Buchfinkengesangs programmiert, um die Rolle der Einflussfaktoren, wie Fehlerquote, Abwanderungsrate und Laufzeit zu ermitteln. Der Wandel des Dialektes erfolgt graduell in Raum und Zeit. Daher sind keine scharfen Dialektgrenzen anzutreffen. Trotz dieser Tatsache markieren die etablierten Strophentypen die Population. 50 % der Juvenilen siedeln am Geburtsort, auf diese Weise bleibt der Dialekt erhalten und Inzest wird vermieden. -Analysiert man das Repertoire benachbarten Männchen bei isolierten Alleen, so entspricht die Gesangsangleichung in etwa dem Zufall. -Intraindividuelle Vergleiche der quantitativen Parameter des jeweiligen Strophentyps wurden saisonal und annuell durchgeführt. Saisonal konnten für einen Strophentyp ein Trend ermittelt werden. Bei jährlichen Vergleichen konnten intraindividuell ausschließlich nicht signifikante Ergebnisse ermittelt

  2. Transient flow combustion

    NASA Technical Reports Server (NTRS)

    Tacina, R. R.

    1984-01-01

    Non-steady combustion problems can result from engine sources such as accelerations, decelerations, nozzle adjustments, augmentor ignition, and air perturbations into and out of the compressor. Also non-steady combustion can be generated internally from combustion instability or self-induced oscillations. A premixed-prevaporized combustor would be particularly sensitive to flow transients because of its susceptability to flashback-autoignition and blowout. An experimental program, the Transient Flow Combustion Study is in progress to study the effects of air and fuel flow transients on a premixed-prevaporized combustor. Preliminary tests performed at an inlet air temperature of 600 K, a reference velocity of 30 m/s, and a pressure of 700 kPa. The airflow was reduced to 1/3 of its original value in a 40 ms ramp before flashback occurred. Ramping the airflow up has shown that blowout is more sensitive than flashback to flow transients. Blowout occurred with a 25 percent increase in airflow (at a constant fuel-air ratio) in a 20 ms ramp. Combustion resonance was found at some conditions and may be important in determining the effects of flow transients.

  3. Transient Optical Sky survey

    NASA Astrophysics Data System (ADS)

    Hadjiyska, Elena Ivanova

    2009-06-01

    Optical transients have been studied in isolated cases, but never mapped into a comprehensive data base in the past. These events vary in duration and signature, yet they are united under the umbrella of time varying observables and represent a significant portion of the dynamical processes in the universe. The Transient Optical Sky Survey (TOSS) System is a dedicated, ground-based system of small optical telescopes, observing nightly at fixed Declination while gathering 90 sec exposures and thus creating a repeated partial map of the sky. Presented here is a brief overview of some of the signatures of transient events and a description of the TOSS system along with the data acquired during the 2008-2009 observing campaign, potentially producing over 100,000 light curves.

  4. Coherent Transient Systems Evaluation

    DTIC Science & Technology

    1993-06-17

    europium doped yttrium silicate in collaboration with IBM Almaden Research Center. Research into divalent ion doped crystals as photon gated materials...noise limited model and ignore the non-ideal properties of the medium, nonlinear effects, spatial crosstalk, gating efficiencies, local heating, the...demonstration of the coherent transient continuous optical processor was performed in europium doped yttrium silicate. Though hyperfine split ground

  5. Bright ZTF transients

    NASA Astrophysics Data System (ADS)

    Fremling, C.; Kulkarni, S. R.; Taggart, K.; Perley, D.

    2018-05-01

    As a part of ongoing commissioning of the Zwicky Transient Facility (ZTF; ATel #11266) Alert Infrastructure, here we report bright probable supernovae identified in the raw alert stream resulting from the public ZTF Northern Sky Survey ("Celestial Cinematagrophy"; see Bellm & Kulkarni, Nature Astronomy 1, 71, 2017).

  6. Transient Astrophysics Probe

    NASA Astrophysics Data System (ADS)

    Camp, Jordan; Transient Astrophysics Probe Team

    2018-01-01

    The Transient Astrophysics Probe (TAP) is a wide-field multi-wavelength transient mission proposed for flight starting in the late 2020s. The mission instruments include unique “Lobster-eye” imaging soft X-ray optics that allow a ~1600 deg2 FoV; a high sensitivity, 1 deg2 FoV soft X-ray telescope; a 1 deg2 FoV Infrared telescope with bandpass 0.6-3 micron; and a set of 8 NaI gamma-ray detectors. TAP’s most exciting capability will be the observation of tens per year of X-ray and IR counterparts of GWs involving stellar mass black holes and neutron stars detected by LIGO/Virgo/KAGRA/LIGO-India, and possibly several per year X-ray counterparts of GWs from supermassive black holes, detected by LISA and Pulsar Timing Arrays. TAP will also discover hundreds of X-ray transients related to compact objects, including tidal disruption events, supernova shock breakouts, and Gamma-Ray Bursts from the epoch of reionization.

  7. Workshop on Radio Transients

    NASA Astrophysics Data System (ADS)

    Croft, Steve; Gaensler, Bryan

    2012-04-01

    abstract-type="normal">SummaryWe are entering a new era in the study of variable and transient radio sources. This workshop discussed the instruments and the strategies employed to study those sources, how they are identified and classified, how results from different surveys can be compared, and how radio observations tie in with those at other wavelengths. The emphasis was on learning what common ground there is between the plethora of on-going projects, how methods and code can be shared, and how best practices regarding survey strategy could be adopted. The workshop featured the four topics below. Each topic commenced with a fairly brief introductory talk, which then developed into discussion. By way of preparation, participants had been invited to upload and discuss one slide per topic to a wiki ahead of the workshop. 1. Telescopes, instrumentation and survey strategy. New radio facilities and on-going projects (including upgrades) are both studying the variability of the radio sky, and searching for transients. The discussion first centred on the status of those facilities, and on projects with a time-domain focus, both ongoing and planned, before turning to factors driving choices of instrumentation, such as phased array versus single pixel feeds, the field of view, spatial and time resolution, frequency and bandwidth, depth, area, and cadence of the surveys. 2. Detection, pipelines, and classification. The workshop debated (a) the factors that influence decisions to study variability in the (u,v) plane, in images, or in catalogues, (b) whether, and how much, pipeline code could potentially be shared between one project and another, and which software packages are best for different approaches, (c) how data are stored and later accessed, and (d) how transients and variables are defined and classified. 3. Statistics, interpretation, and synthesis. It then discussed how (i) the choice of facility and strategy and (ii) detection and classification schemes

  8. Thermal transient anemometer

    DOEpatents

    Bailey, James L.; Vresk, Josip

    1989-01-01

    A thermal transient anemometer having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe.

  9. Thermal transient anemometer

    DOEpatents

    Bailey, J.L.; Vresk, J.

    1989-07-18

    A thermal transient anemometer is disclosed having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe. 12 figs.

  10. Characterizing Nanoscale Transient Communication.

    PubMed

    Chen, Yifan; Anwar, Putri Santi; Huang, Limin; Asvial, Muhamad

    2016-04-01

    We consider the novel paradigm of nanoscale transient communication (NTC), where certain components of the small-scale communication link are physically transient. As such, the transmitter and the receiver may change their properties over a prescribed lifespan due to their time-varying structures. The NTC systems may find important applications in the biomedical, environmental, and military fields, where system degradability allows for benign integration into life and environment. In this paper, we analyze the NTC systems from the channel-modeling and capacity-analysis perspectives and focus on the stochastically meaningful slow transience scenario, where the coherence time of degeneration Td is much longer than the coding delay Tc. We first develop novel and parsimonious models to characterize the NTC channels, where three types of physical layers are considered: electromagnetism-based terahertz (THz) communication, diffusion-based molecular communication (DMC), and nanobots-assisted touchable communication (TouchCom). We then revisit the classical performance measure of ϵ-outage channel capacity and take a fresh look at its formulations in the NTC context. Next, we present the notion of capacity degeneration profile (CDP), which describes the reduction of channel capacity with respect to the degeneration time. Finally, we provide numerical examples to demonstrate the features of CDP. To the best of our knowledge, the current work represents a first attempt to systematically evaluate the quality of nanoscale communication systems deteriorating with time.

  11. Measurand transient signal suppressor

    NASA Technical Reports Server (NTRS)

    Bozeman, Richard J., Jr. (Inventor)

    1994-01-01

    A transient signal suppressor for use in a controls system which is adapted to respond to a change in a physical parameter whenever it crosses a predetermined threshold value in a selected direction of increasing or decreasing values with respect to the threshold value and is sustained for a selected discrete time interval is presented. The suppressor includes a sensor transducer for sensing the physical parameter and generating an electrical input signal whenever the sensed physical parameter crosses the threshold level in the selected direction. A manually operated switch is provided for adapting the suppressor to produce an output drive signal whenever the physical parameter crosses the threshold value in the selected direction of increasing or decreasing values. A time delay circuit is selectively adjustable for suppressing the transducer input signal for a preselected one of a plurality of available discrete suppression time and producing an output signal only if the input signal is sustained for a time greater than the selected suppression time. An electronic gate is coupled to receive the transducer input signal and the timer output signal and produce an output drive signal for energizing a control relay whenever the transducer input is a non-transient signal which is sustained beyond the selected time interval.

  12. Reciprocal capacitance transients?

    NASA Astrophysics Data System (ADS)

    Gfroerer, Tim; Simov, Peter; Wanlass, Mark

    2007-03-01

    When the reverse bias across a semiconductor diode is changed, charge carriers move to accommodate the appropriate depletion thickness, producing a simultaneous change in the device capacitance. Transient capacitance measurements can reveal inhibited carrier motion due to trapping, where the depth of the trap can be evaluated using the temperature-dependent escape rate. However, when we employ this technique on a GaAs0.72P0.28 n+/p diode (which is a candidate for incorporation in multi-junction solar cells), we observe a highly non-exponential response under a broad range of experimental conditions. Double exponential functions give good fits, but lead to non-physical results. The deduced rates depend on the observation time window and fast and slow rates, which presumably correspond to deep and shallow levels, have identical activation energies. Meanwhile, we have discovered a universal linear relationship between the inverse of the capacitance and time. An Arrhenius plot of the slope of the reciprocal of the transient yields an activation energy of approximately 0.4 eV, independent of the observation window and other experimental conditions. The reciprocal behavior leads us to hypothesize that hopping, rather than escape into high-mobility bands, may govern the transport of trapped holes in this system.

  13. Verbesserte Visualisierung der Koronararterien in MSCT-Daten mit direkter Vergleichbarkeit zur Angiographie

    NASA Astrophysics Data System (ADS)

    Lacalli, Christina; Jähne, Marion; Wesarg, Stefan

    In diesem Beitrag stellen wir neue, automatisierte Verfahren zur Visualisierung der Koronararterien einerseits und für eine direkte Vergleichbarkeit mit konventionellen Angiogrammen andererseits vor. Unser Ansatz umfasst Methoden für die automatische Extraktion des Herzens aus kontrastverstärkten CT-Daten, sowie für die Maskierung grosser kontrastmittelgefüllter Kavitäten des Herzens, um die Sichtbarkeit der Koronararterien bei der Darstellung mittels Volumenrendering zu verbessern. Zum direkten Vergleich mit konventionellen Angiographien wurde ein Verfahren zur automatischen Generierung von Projektionsansichten aus den CT-Daten entwickelt.

  14. Calculating transient rates from surveys

    NASA Astrophysics Data System (ADS)

    Carbone, D.; van der Horst, A. J.; Wijers, R. A. M. J.; Rowlinson, A.

    2017-03-01

    We have developed a method to determine the transient surface density and transient rate for any given survey, using Monte Carlo simulations. This method allows us to determine the transient rate as a function of both the flux and the duration of the transients in the whole flux-duration plane rather than one or a few points as currently available methods do. It is applicable to every survey strategy that is monitoring the same part of the sky, regardless the instrument or wavelength of the survey, or the target sources. We have simulated both top-hat and Fast Rise Exponential Decay light curves, highlighting how the shape of the light curve might affect the detectability of transients. Another application for this method is to estimate the number of transients of a given kind that are expected to be detected by a survey, provided that their rate is known.

  15. The joy of transient chaos.

    PubMed

    Tél, Tamás

    2015-09-01

    We intend to show that transient chaos is a very appealing, but still not widely appreciated, subfield of nonlinear dynamics. Besides flashing its basic properties and giving a brief overview of the many applications, a few recent transient-chaos-related subjects are introduced in some detail. These include the dynamics of decision making, dispersion, and sedimentation of volcanic ash, doubly transient chaos of undriven autonomous mechanical systems, and a dynamical systems approach to energy absorption or explosion.

  16. The ZTF Bright Transient Survey

    NASA Astrophysics Data System (ADS)

    Fremling, C.; Sharma, Y.; Kulkarni, S. R.; Miller, A. A.; Taggart, K.; Perley, D. A.; Gooba, A.

    2018-06-01

    As a supplement to the Zwicky Transient Facility (ZTF; ATel #11266) public alerts (ATel #11685) we plan to report (following ATel #11615) bright probable supernovae identified in the raw alert stream from the ZTF Northern Sky Survey ("Celestial Cinematography"; see Bellm & Kulkarni, 2017, Nature Astronomy 1, 71) to the Transient Name Server (https://wis-tns.weizmann.ac.il) on a daily basis; the ZTF Bright Transient Survey (BTS; see Kulkarni et al., 2018; arXiv:1710.04223).

  17. Transient Infrared Emission Spectroscopy

    NASA Astrophysics Data System (ADS)

    Jones, Roger W.; McClelland, John F.

    1989-12-01

    Transient Infrared Emission Spectroscopy (TIRES) is a new technique that reduces the occurrence of self-absorption in optically thick solid samples so that analytically useful emission spectra may be observed. Conventional emission spectroscopy, in which the sample is held at an elevated, uniform temperature, is practical only for optically thin samples. In thick samples the emission from deep layers of the material is partially absorbed by overlying layers.1 This self-absorption results in emission spectra from most optically thick samples that closely resemble black-body spectra. The characteristic discrete emission bands are severely truncated and altered in shape. TIRES bypasses this difficulty by using a laser to heat only an optically thin surface layer. The increased temperature of the layer is transient since the layer will rapidly cool and thicken by thermal diffusion; hence the emission collection must be correlated with the laser heating. TIRES may be done with both pulsed and cw lasers.2,3 When a pulsed laser is used, the spectrometer sampling must be synchronized with the laser pulsing so that only emission during and immediately after each laser pulse is observed.3 If a cw laser is used, the sample must move rapidly through the beam. The hot, transient layer is then in the beam track on the sample at and immediately behind the beam position, so the spectrometer field of view must be limited to this region near the beam position.2 How much self-absorption the observed emission suffers depends on how thick the heated layer has grown by thermal diffusion when the spectrometer samples the emission. Use of a pulsed laser synchronized with the spectrometer sampling readily permits reduction of the time available for heat diffusion to about 100 acs .3 When a cw laser is used, the heat-diffusion time is controlled by how small the spectrometer field of view is and by how rapidly the sample moves past within this field. Both a very small field of view and a

  18. The Zwicky Transient Facility

    NASA Astrophysics Data System (ADS)

    Kulkarni, Shrinivas R.

    2016-01-01

    The Zwicky Transient Facility (ZTF) has been designed with a singular focus: a systematic exploration of the night sky at a magnitude level well suited for spectral classification and follow up with the existing class of 4-m to 10-m class telescopes. ZTF is the successor to the Palomar Transient Factory (PTF). The discovery engine for ZTF is a 47 square degree camera (realized through 16 e2V monolithic CCDs) that fills the entire focal plane of the 48-inch Oschin telescope of the Palomar Observatory. Single 30-s epoch sensitivity is about 20.5 in g and R bands. The Infarared Processing & Analysis Center (IPAC) is the data center for ZTF. ZTF is a public-private partnership with equal contributions from a consortium of world-wide partners and an NSF MSIP grant. Forty percent of ZTF time is set aside for two major community surveys: a 3-day cadence survey of high latitudes (to mimic LSST) and a time domain survey of the entire Northern Galactic plane. We expect first light in February 2017 and begin a 3-year survey starting summer of 2017. The first year will be spent on building up deep reference images of the sky (a must for transient surveys). During the second year IPAC will deliver near archival quality photometric products within 12 hours of observations. By comparison to reference images photometric alerts will be sent out. Year 3 will see the near real-time release of image differencing products. A Community Science Advisory Committee (CSAC), chaired by S. Ridgway (NOAO), has been set up to both advise the PI and to ensure that the US community's interests are well served. Astronomers interested in getting a head start on ZTF may wish to peruse the data releases from PTF. Young people (or young at heart) may wish to attend the annual summer school on PTF/ZTF (August, Caltech campus). The Principal Investigator (PI) for the project is S. Kulkarni and the Project Scientist is Eric Bellm.For further details please consult http://www.ptf.caltech.edu/ztf

  19. Transient complex peroxisomal interactions

    PubMed Central

    Bonekamp, Nina A.; Schrader, Michael

    2012-01-01

    Mitochondria and peroxisomes are ubiquitous subcellular organelles that fulfill essential metabolic functions, rendering them indispensable for human development and health. Both are highly dynamic organelles that can undergo remarkable changes in morphology and number to accomplish cellular needs. While mitochondrial dynamics are also regulated by frequent fusion events, the fusion of mature peroxisomes in mammalian cells remained a matter of debate. In our recent study, we clarified systematically that there is no complete fusion of mature peroxisomes analogous to mitochondria. Moreover, in contrast to key division components such as DLP1, Fis1 or Mff, mitochondrial fusion proteins were not localized to peroxisomes. However, we discovered and characterized novel transient, complex interactions between individual peroxisomes which may contribute to the homogenization of the often heterogeneous peroxisomal compartment, e.g., by distribution of metabolites, signals or other “molecular information” via interperoxisomal contact sites. PMID:23336019

  20. Optical transient monitor

    NASA Astrophysics Data System (ADS)

    Bernas, Martin; Páta, Petr; Hudec, René; Soldán, Jan; Rezek, Tomáš; Castro-Tirado, Alberto J.

    1998-05-01

    Although there are several optical GRB follow-up systems in operation and/or in development, some of them with a very short response time, they will never be able to provide true simultaneous (no delay) and pre-burst optical data for GRBs. We report on the development and tests of a monitoring experiment expected to be put into test operation in 1998. The system should detect Optical Transients down to mag 6-7 (few seconds duration assumed) over a wide field of view. The system is based on the double CCD wide-field cameras ST8. For the real time evaluation of the signal from both cameras, two TMS 320C40 processors are used. Using two channels differing in spectral sensitivity and processing of temporal sequence of images allows us to eliminate man-made objects and defects of the CCD electronics. The system is controlled by a standard PC computer.

  1. Transient osteoporosis of pregnancy.

    PubMed

    Maliha, George; Morgan, Jordan; Vrahas, Mark

    2012-08-01

    Transient osteoporosis of pregnancy (TOP) is a rare yet perhaps under-reported condition that has affected otherwise healthy pregnancies throughout the world. The condition presents suddenly in the third trimester of a usually uneventful pregnancy and progressively immobilizes the mother. Radiographic studies detect drastic loss of bone mass, elevated rates of turnover in the bone, and oedema in the affected portion. Weakness of the bone can lead to fractures during delivery and other complications for the mother. Then, within weeks of labour, symptoms and radiological findings resolve. Aetiology is currently unknown, although neural, vascular, haematological, endocrine, nutrient-deficiency, and other etiologies have been proposed. Several treatments have also been explored, including simple bed rest, steroids, bisphosphonates, calcitonin, induced termination of pregnancy, and surgical intervention. The orthopedist plays an essential role in monitoring the condition (and potential complications) as well as ensuring satisfactory outcomes for both the mother and newborn. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Line transients with corona

    SciT

    Saied, M.M.; Safar, Y.A.; Salama, M.H.

    1987-01-01

    This paper investigates the effect of corona on the electromagnetic transients along high voltage overhead lines. A method is presented to simulate the line by dividing it into a number of sections connected in cascade. For {ital n} line sections, the number of the unknown variables is 2{ital n} + 1. The method allows any waveform of the exciting voltage function, as well as any impedance loading condition. The corona is represented by voltage-dependent shunt current sources. A systematic way for writing a sufficient number of differential equations is shown. For their solution, a digital computer subroutine based on themore » Runge--Kutta--Verner method was used. An artificial frequency-dependent damping by means of linear resistors was used to suppress the Gibb's oscillations in the solution. The proposed method is applied to study the transients on a 40 km high voltage line with 30-ft flat phase spacing and a single 1.4 inch ACSR conductor per phase. The exciting voltage has a double-exponential impulse waveform. Solutions are given for three values of resistive loads Z{sub {ital c}}2Z{sub {ital c}} and Z{sub {ital c}}/2, where Z{sub {ital c}} is the line surge impedance. The results of two interesting cases of inductive and capacitive loads are also given. Physical interpretations for the different solutions are given. Also, the current-voltage duality between inductive and capacitive loads is recognized. The corona was found to attenuate and distort the travelling waves. For example, during one wave excursion, the reduction of the current wave peaks can reach values as high as 8.5%. The effect is more noticeable in the current than in the voltage waves. As expected, it increases also with the line corona losses. The effect of the increase of the line effective capacitance due to the corona discharge is also demonstrated.« less

  3. Transient Go: A Mobile App for Transient Astronomy Outreach

    NASA Astrophysics Data System (ADS)

    Crichton, D.; Mahabal, A.; Djorgovski, S. G.; Drake, A.; Early, J.; Ivezic, Z.; Jacoby, S.; Kanbur, S.

    2016-12-01

    Augmented Reality (AR) is set to revolutionize human interaction with the real world as demonstrated by the phenomenal success of `Pokemon Go'. That very technology can be used to rekindle the interest in science at the school level. We are in the process of developing a prototype app based on sky maps that will use AR to introduce different classes of astronomical transients to students as they are discovered i.e. in real-time. This will involve transient streams from surveys such as the Catalina Real-time Transient Survey (CRTS) today and the Large Synoptic Survey Telescope (LSST) in the near future. The transient streams will be combined with archival and latest image cut-outs and other auxiliary data as well as historical and statistical perspectives on each of the transient types being served. Such an app could easily be adapted to work with various NASA missions and NSF projects to enrich the student experience.

  4. Spitzer Characterization of Transients from the Palomar Transient Factory

    NASA Astrophysics Data System (ADS)

    Kasliwal, Mansi; Ofek, Eran; Corsi, Alessandra; Nugent, Peter; Kulkarni, Shri; Cao, Yi; Helou, George; Gal-Yam, Avishay; Arcavi, Iair; Ben-Ami, Sagi

    2012-12-01

    We propose to continue Spitzer/IRAC follow-up of optical transients discovered by the Palomar Transient Factory. Our goals are: (i) probe the mass loss history and characterize the circumstellar environment of supernovae. (ii) construct a late-time bolometric light curve; the mid-infrared observations complement our ground-based optical and near-infrared data and (iii) understand the physical origin of new classes of transients (specifically, intermediate luminosity red transients) where the mystery is literally enshrouded in dust. We select extremely nearby supernovae, both thermonuclear and core-collapse, where the thermal echo is easily detectable in the mid-infrared. We also select peculiar supernovae that show tell-tale signs of circumstellar interaction. We also select rare and red gap transients in the local universe for IRAC follow-up. Additionally, we request low-impact target of opportunity observations for new discoveries in 2013. Our total request is 24 hrs.

  5. Spitzer Characterization of Transients from the Palomar Transient Factory

    NASA Astrophysics Data System (ADS)

    Kasliwal, Mansi; Goobar, Ariel; Johansson, Joel; Cenko, Brad; Ofek, Eran; Nugent, Peter; Kulkarni, Shri; Cao, Yi; Helou, George; Gal-Yam, Avishay; Arcavi, Iair; Ben-Ami, Sagi

    2013-10-01

    We propose to continue Spitzer/IRAC follow-up of optical transients discovered by the Palomar Transient Factory. Our goals are: (i) probe the mass loss history and characterize the circumstellar environment of supernovae. (ii) construct a late-time bolometric light curve; the mid-infrared observations complement our ground-based optical and near-infrared data and (iii) understand the physical origin of new classes of transients (specifically, intermediate luminosity red transients) where the mystery is literally enshrouded in dust. We select extremely nearby supernovae, both thermonuclear and core-collapse, where the thermal echo is easily detectable in the mid-infrared. We also select peculiar supernovae that show tell-tale signs of circumstellar interaction. We also select rare and red gap transients in the local universe. Additionally, we request low-impact target of opportunity observations for new discoveries in 2014. Our total request is 17 hrs.

  6. Zur (FurB) is a key factor in the control of the oxidative stress response in Anabaena sp. PCC 7120.

    PubMed

    Sein-Echaluce, Violeta C; González, Andrés; Napolitano, Mauro; Luque, Ignacio; Barja, Francisco; Peleato, M Luisa; Fillat, María F

    2015-06-01

    Iron and zinc are necessary nutrients whose homeostasis is tightly controlled by members of the ferric uptake regulator (FUR) superfamily in the cyanobacterium Anabaena sp. PCC7120. Although the link between iron metabolism and oxidative stress management is well documented, little is known about the connection between zinc homeostasis and the oxidative stress response in cyanobacteria. Zinc homeostasis in Anabaena is controlled by Zur, also named FurB. When overexpressed in Escherichia coli, Zur (FurB) improved cell survival during oxidative stress. In order to investigate the possible correlation between Zur and the oxidative stress response in Anabaena, zur deletion and zur-overexpressing strains have been constructed, and the consequences of Zur imbalance evaluated. The lack of Zur increased sensitivity to hydrogen peroxide (H2 O2 ), whereas an excess of Zur enhanced oxidative stress resistance. Both mutants displayed pleiotropic phenotypes, including alterations on the filament surfaces observable by scanning electron microscopy, reduced content of endogenous H2 O2 and altered expression of sodA, catalases and several peroxiredoxins. Transcriptional and biochemical analyses unveiled that the appropriate level of Zur is required for proper control of the oxidative stress response and allowed us to identify major antioxidant enzymes as novel members of the Zur regulon. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. Summer 1993 Transient Student Report.

    ERIC Educational Resources Information Center

    Kent State Univ., Warren, OH. Office of Institutional Research.

    A study was conducted by the Trumbull Campus (TC) of Kent State University, in Ohio, to determine the motivations, objectives, and level of satisfaction of transient students, or students pursuing a degree at another institution but enrolled in courses at TC. Surveys were mailed to 50 transient students enrolled in summer 1993, with completed…

  8. ZTF Bright Transient Survey classifications

    NASA Astrophysics Data System (ADS)

    Fremling, C.; Sharma, Y.; Skulkarni, S. R.; Walters, R.; Blagorodnova, N.; Neill, J. D.; Miller, A. A.; Taggart, K.; Perley, D. A.; Goobar, A.; Graham, M. L.

    2018-06-01

    The Zwicky Transient Facility (ZTF; ATel #11266) Bright Transient Survey (BTS; ATel #11688) reports classifications of the following targets. Spectra have been obtained with the Spectral Energy Distribution Machine (SEDM) (range 350-950nm, spectral resolution R 100) mounted on the Palomar 60-inch (P60) telescope (Blagorodnova et. al. 2018, PASP, 130, 5003).

  9. The MWA Transients Survey (MWATS).

    NASA Astrophysics Data System (ADS)

    Bell, M.; Murphy, T.; Kaplan, D. L.; Croft, S. D.; Hancock, P.; Rowlinson, A.; Wayth, R.; Gaensler, B.; Hurley-Walker, N.; Offringa, A.; Loi, C.; Bannister, K.; Trott, C.; Marquart, J.

    2017-01-01

    We propose the continuation of the MWA transients survey to search for and monitor low frequency transient and variable radio sources in the southern sky. This proposal is aimed at commensally utilising data from the GLEAM-X (G0008) project in semester 2017-A. The aim of this commensal data acquisition is to commission long baseline observations for transient science. In particular this will involve studying the impact of the ionosphere on calibration and imaging, and developing the techniques needed to produce science quality data products. The proposed drift scans with LST locking (see G0008 proposal) are particularly exciting as we can test image subtraction for transient and variable identification. This survey is targeted at studying objects such as AGN (intrinsic and extrinsic variability), long duration synchrotron emitters, pulsars and transients of unknown origin. The maps generated from this survey will be analysed with the Variables and Slow Transients (VAST) detection pipeline. The motivation for this survey is as follows: (i) To obtain temporal data on an extremely large and robust sample of low frequency sources to explore and quantify both intrinsic and extrinsic variability; (ii) To search and find new classes of low frequency radio transients that previously remained undetected and obscured from multi-wavelength discovery; (iii) To place rigorous statistics on the occurrence of both transients and variables prior to the Australian SKA era.

  10. Perturbations for transient acceleration

    SciT

    Vargas, Cristofher Zuñiga; Zimdahl, Winfried; Hipólito-Ricaldi, Wiliam S., E-mail: win_unac@hotmail.com, E-mail: hipolito@ceunes.ufes.br, E-mail: winfried.zimdahl@pq.cnpq.br

    2012-04-01

    According to the standard ΛCDM model, the accelerated expansion of the Universe will go on forever. Motivated by recent observational results, we explore the possibility of a finite phase of acceleration which asymptotically approaches another period of decelerated expansion. Extending an earlier study on a corresponding homogeneous and isotropic dynamics, in which interactions between dark matter and dark energy are crucial, the present paper also investigates the dynamics of the matter perturbations both on the Newtonian and General Relativistic (GR) levels and quantifies the potential relevance of perturbations of the dark-energy component. In the background, the model is tested againstmore » the Supernova type Ia (SNIa) data of the Constitution set and on the perturbative level against growth rate data, among them those of the WiggleZ survey, and the data of the 2dFGRS project. Our results indicate that a transient phase of accelerated expansion is not excluded by current observations.« less

  11. Transient Chaotic Mixing

    NASA Astrophysics Data System (ADS)

    Gollub, J. P.; Rothstein, David; Losert, Wolfgang

    1998-11-01

    We report a systematic experimental study of transient mixing in a family of two-dimensional vortex flows driven by magneto-hydrodynamic forces. The forcing method allows a number of distinct cases to be investigated spanning the range from Lagrangian chaos to 2D turbulence. Both spatially ordered and spatially irregular forcing situations are considered. The basic methodology is to label half of the fluid layer with a fluorescent dye, and to measure the subsequent dye distribution with a precision CCD camera. Diagnostics are devised that allow us separately to monitor the stretching of fluid elements and development of fine striations, diffusive smearing, and the transport of material across the cell. Various statistical measures are used, including the probability distribution, the scalar gradient PDF, and the power spectrum. We find major differences between the time-periodic and nonperiodic cases. The former generally show evidence of "KAM surfaces" or barriers to transport, so that mixing, while substantial, is incomplete. After a modest number of cycles (typically 10-20), the flow structure usually reaches a slowly evolving limiting form whose amplitude then decays, as has been proposed in several theoretical studies.

  12. Transient regional osteoporosis.

    PubMed

    Cano-Marquina, Antonio; Tarín, Juan J; García-Pérez, Miguel-Ángel; Cano, Antonio

    2014-04-01

    Transient regional osteoporosis (TRO) is a disease that predisposes to fragility fracture in weight bearing joints of mid-life women and men. Pregnant women may also suffer the process, usually at the hip. The prevalence of TRO is lower than the systemic form, associated with postmenopause and advanced age, but may be falsely diminished by under-diagnosis. The disease may be uni- or bilateral, and may migrate to distinct joints. One main feature of TRO is spontaneous recovery. Pain and progressive limitation in the functionality of the affected joint(s) are key symptoms. In the case of the form associated with pregnancy, difficulties in diagnosis derive from the relatively young age at presentation and from the clinical overlapping with the frequent aches during gestation. Densitometric osteoporosis in the affected region is not always present, but bone marrow edema, with or without joint effusion, is detected by magnetic resonance. There are not treatment guidelines, but the association of antiresorptives to symptomatic treatment seems to be beneficial. Surgery or other orthopedic interventions can be required for specific indications, like hip fracture, intra-medullary decompression, or other. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Robuste Verzweigungserkennung von Gefäßen in CTA-Datensätzen zur modellbasierten Extraktion der Centerline

    NASA Astrophysics Data System (ADS)

    Beck, Thomas; Fritz, Dominik; Biermann, Christina; Dillmann, Rüdiger

    Bei der Befundung und Visualisierung von Blutgefäßen ist deren Centerline von zentraler Bedeutung. Die Unterscheidung zwischen unverzweigten Abschnitten des Gefäßes und Verzweigungsbereichen ermöglicht den Einsatz spezialisierter und sehr effizienter Algorithmen zur modellbasierten Extraktion der Centerline. In diesem Artikel wird ein robustes Verfahren zur Verzweigungserkennung vorgestellt. Das Verfahren beruht auf einem Front-Propagation-Ansatz mit dynamisch angepassten Schwellwerten und einer anschließenden Clusteranalyse. Die vorgestellte Methode zur Verzweigungserkennung wurde als Komponente einer Architektur zur Extraktion der Centerline auf handannotierten Datensätzen getestet. Erste Ergebnisse sind sehr vielversprechend und ermöglichen auch bei pathologischen Gefäßen eine robuste Detektion von Gefäßverzweigungen.

  14. The rapid transient surveyor

    NASA Astrophysics Data System (ADS)

    Baranec, C.; Lu, J. R.; Wright, S. A.; Tonry, J.; Tully, R. B.; Szapudi, I.; Takamiya, M.; Hunter, L.; Riddle, R.; Chen, S.; Chun, M.

    2016-07-01

    The Rapid Transient Surveyor (RTS) is a proposed rapid-response, high-cadence adaptive optics (AO) facility for the UH 2.2-m telescope on Maunakea. RTS will uniquely address the need for high-acuity and sensitive near-infrared spectral follow-up observations of tens of thousands of objects in mere months by combining an excellent observing site, unmatched robotic observational efficiency, and an AO system that significantly increases both sensitivity and spatial resolving power. We will initially use RTS to obtain the infrared spectra of 4,000 Type Ia supernovae identified by the Asteroid Terrestrial-Impact Last Alert System over a two year period that will be crucial to precisely measuring distances and mapping the distribution of dark matter in the z < 0.1 universe. RTS will comprise an upgraded version of the Robo-AO laser AO system and will respond quickly to target-of-opportunity events, minimizing the time between discovery and characterization. RTS will acquire simultaneous-multicolor images with an acuity of 0.07-0.10" across the entire visible spectrum (20% i'-band Strehl in median conditions) and <0.16" in the near infrared, and will detect companions at 0.5" at contrast ratio of 500. The system will include a high-efficiency prism integral field unit spectrograph: R = 70-140 over a total bandpass of 840-1830nm with an 8.7" by 6.0" field of view (0.15" spaxels). The AO correction boosts the infrared point-source sensitivity of the spectrograph against the sky background by a factor of seven for faint targets, giving the UH 2.2-m the H-band sensitivity of a 5.7-m telescope without AO.

  15. Transient-Switch-Signal Suppressor

    NASA Technical Reports Server (NTRS)

    Bozeman, Richard J., Jr.

    1995-01-01

    Circuit delays transmission of switch-opening or switch-closing signal until after preset suppression time. Used to prevent transmission of undesired momentary switch signal. Basic mode of operation simple. Beginning of switch signal initiates timing sequence. If switch signal persists after preset suppression time, circuit transmits switch signal to external circuitry. If switch signal no longer present after suppression time, switch signal deemed transient, and circuit does not pass signal on to external circuitry, as though no transient switch signal. Suppression time preset at value large enough to allow for damping of underlying pressure wave or other mechanical transient.

  16. Bacillus licheniformis Contains Two More PerR-Like Proteins in Addition to PerR, Fur, and Zur Orthologues

    PubMed Central

    Ju, Shin-Yeong; Yang, Yoon-Mo; Ryu, Su-Hyun; Kwon, Yumi; Won, Young-Bin; Lee, Yeh-Eun; Youn, Hwan; Lee, Jin-Won

    2016-01-01

    The ferric uptake regulator (Fur) family proteins include sensors of Fe (Fur), Zn (Zur), and peroxide (PerR). Among Fur family proteins, Fur and Zur are ubiquitous in most prokaryotic organisms, whereas PerR exists mainly in Gram positive bacteria as a functional homologue of OxyR. Gram positive bacteria such as Bacillus subtilis, Listeria monocytogenes and Staphylococcus aureus encode three Fur family proteins: Fur, Zur, and PerR. In this study, we identified five Fur family proteins from B. licheniformis: two novel PerR-like proteins (BL00690 and BL00950) in addition to Fur (BL05249), Zur (BL03703), and PerR (BL00075) homologues. Our data indicate that all of the five B. licheniformis Fur homologues contain a structural Zn2+ site composed of four cysteine residues like many other Fur family proteins. Furthermore, we provide evidence that the PerR-like proteins (BL00690 and BL00950) as well as PerRBL (BL00075), but not FurBL (BL05249) and ZurBL (BL03703), can sense H2O2 by histidine oxidation with different sensitivity. We also show that PerR2 (BL00690) has a PerR-like repressor activity for PerR-regulated genes in vivo. Taken together, our results suggest that B. licheniformis contains three PerR subfamily proteins which can sense H2O2 by histidine oxidation not by cysteine oxidation, in addition to Fur and Zur. PMID:27176811

  17. CHARACTERIZATION OF TRANSIENT PUFF EMISSIONS ...

    EPA Pesticide Factsheets

    Symposium Paper Transient puff emissions were characterized from burning carpet charges that were fed to a pilotscale rotary kiln combustor to assess the potential impact on emissions of using post-consumer carpet as an alternative fuel in cement kilns.

  18. Transient Tsunamis in Lakes

    NASA Astrophysics Data System (ADS)

    Couston, L.; Mei, C.; Alam, M.

    2013-12-01

    A large number of lakes are surrounded by steep and unstable mountains with slopes prone to failure. As a result, landslides are likely to occur and impact water sitting in closed reservoirs. These rare geological phenomena pose serious threats to dam reservoirs and nearshore facilities because they can generate unexpectedly large tsunami waves. In fact, the tallest wave experienced by contemporary humans occurred because of a landslide in the narrow bay of Lituya in 1958, and five years later, a deadly landslide tsunami overtopped Lake Vajont's dam, flooding and damaging villages along the lakefront and in the Piave valley. If unstable slopes and potential slides are detected ahead of time, inundation maps can be drawn to help people know the risks, and mitigate the destructive power of the ensuing waves. These maps give the maximum wave runup height along the lake's vertical and sloping boundaries, and can be obtained by numerical simulations. Keeping track of the moving shorelines along beaches is challenging in classical Eulerian formulations because the horizontal extent of the fluid domain can change over time. As a result, assuming a solid slide and nonbreaking waves, here we develop a nonlinear shallow-water model equation in the Lagrangian framework to address the problem of transient landslide-tsunamis. In this manner, the shorelines' three-dimensional motion is part of the solution. The model equation is hyperbolic and can be solved numerically by finite differences. Here, a 4th order Runge-Kutta method and a compact finite-difference scheme are implemented to integrate in time and spatially discretize the forced shallow-water equation in Lagrangian coordinates. The formulation is applied to different lake and slide geometries to better understand the effects of the lake's finite lengths and slide's forcing mechanism on the generated wavefield. Specifically, for a slide moving down a plane beach, we show that edge-waves trapped by the shoreline and free

  19. Transient Alerts in LSST

    NASA Astrophysics Data System (ADS)

    Kantor, J.

    During LSST observing, transient events will be detected and alerts generated at the LSST Archive Center at NCSA in Champaign-Illinois. As a very high rate of alerts is expected, approaching ˜ 10 million per night, we plan for VOEvent-compliant Distributor/Brokers (http://voevent.org) to be the primary end-points of the full LSST alert streams. End users will then use these Distributor/Brokers to classify and filter events on the stream for those fitting their science goals. These Distributor/Brokers are envisioned to be operated as a community service by third parties who will have signed MOUs with LSST. The exact identification of Distributor/Brokers to receive alerts will be determined as LSST approaches full operations and may change over time, but it is in our interest to identify and coordinate with them as early as possible. LSST will also operate a limited Distributor/Broker with a filtering capability at the Archive Center, to allow alerts to be sent directly to a limited number of entities that for some reason need to have a more direct connection to LSST. This might include, for example, observatories with significant follow-up capabilities whose observing may temporarily be more directly tied to LSST observing. It will let astronomers create simple filters that limit what alerts are ultimately forwarded to them. These user defined filters will be possible to specify using an SQL-like declarative language, or short snippets of (likely Python) code. We emphasize that this LSST-provided capability will be limited, and is not intended to satisfy the wide variety of use cases that a full-fledged public Event Distributor/Broker could. End users will not be able to subscribe to full, unfiltered, alert streams coming directly from LSST. In this session, we will discuss anticipated LSST data rates, and capabilities for alert processing and distribution/brokering. We will clarify what the LSST Observatory will provide versus what we anticipate will be a

  20. Characterizing SI Engine Transient Fuel Consumption in ...

    EPA Pesticide Factsheets

    Examine typical transient engine operation encountered over the EPA's vehicle and engine testing drive cycles to characterize that transient fuel usage, and then describe the changes made to ALPHA to better model transient engine operation. To present an approach to capture dynamic fuel consumption during engine transients and then implement these identified characteristics in ALPHA.

  1. Wide Field Radio Transient Surveys

    NASA Astrophysics Data System (ADS)

    Bower, Geoffrey

    2011-04-01

    The time domain of the radio wavelength sky has been only sparsely explored. Nevertheless, serendipitous discovery and results from limited surveys indicate that there is much to be found on timescales from nanoseconds to years and at wavelengths from meters to millimeters. These observations have revealed unexpected phenomena such as rotating radio transients and coherent pulses from brown dwarfs. Additionally, archival studies have revealed an unknown class of radio transients without radio, optical, or high-energy hosts. The new generation of centimeter-wave radio telescopes such as the Allen Telescope Array (ATA) will exploit wide fields of view and flexible digital signal processing to systematically explore radio transient parameter space, as well as lay the scientific and technical foundation for the Square Kilometer Array. Known unknowns that will be the target of future transient surveys include orphan gamma-ray burst afterglows, radio supernovae, tidally-disrupted stars, flare stars, and magnetars. While probing the variable sky, these surveys will also provide unprecedented information on the static radio sky. I will present results from three large ATA surveys (the Fly's Eye survey, the ATA Twenty CM Survey (ATATS), and the Pi GHz Survey (PiGSS)) and several small ATA transient searches. Finally, I will discuss the landscape and opportunities for future instruments at centimeter wavelengths.

  2. Transient Faults in Computer Systems

    NASA Technical Reports Server (NTRS)

    Masson, Gerald M.

    1993-01-01

    A powerful technique particularly appropriate for the detection of errors caused by transient faults in computer systems was developed. The technique can be implemented in either software or hardware; the research conducted thus far primarily considered software implementations. The error detection technique developed has the distinct advantage of having provably complete coverage of all errors caused by transient faults that affect the output produced by the execution of a program. In other words, the technique does not have to be tuned to a particular error model to enhance error coverage. Also, the correctness of the technique can be formally verified. The technique uses time and software redundancy. The foundation for an effective, low-overhead, software-based certification trail approach to real-time error detection resulting from transient fault phenomena was developed.

  3. Studies of Transient Meteor Activity

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter M. M.

    2002-01-01

    Meteoroids bombard Earth's atmosphere daily, but occasionally meteor rates increase to unusual high levels when Earth crosses the relatively fresh ejecta of comets. These transient events in meteor activity provide clues about the whereabouts of Earth-threatening long-period comets, the mechanisms of large-grain dust ejection from comets, and the particle composition and size distribution of the cometary ejecta. Observations of these transient events provide important insight in natural processes that determine the large grain dust environment of comets, in natural phenomena that were prevalent during the time of the origin of life, and in processes that determine the hazard of civilizations to large impacts and of man-made satellites to the periodic blizzard of small meteoroids. In this proposal, three tasks form a coherent program aimed at elucidating various aspects of meteor outbursts, with special reference to planetary astronomy and astrobiology. Task 1 was a ground-based effort to observe periods of transient meteor activity. This includes: (1) stereoscopic imaging of meteors during transient meteor events for measurements of particle size distribution, meteoroid orbital dispersions and fluxes; and (2) technical support for Global-MS-Net, a network of amateur-operated automatic counting stations for meteor reflections from commercial VHF radio and TV broadcasting stations, keeping a 24h vigil on the level of meteor activity for the detection of new meteor streams. Task 2 consisted of ground-based and satellite born spectroscopic observations of meteors and meteor trains during transient meteor events for measurements of elemental composition, the presence of organic matter in the meteoroids, and products generated by the interaction of the meteoroid with the atmosphere. Task 3 was an airborne effort to explore the 2000 Leonid meteor outbursts, which are anticipated to be the most significant of transient meteor activity events in the remainder of the

  4. ZTF Bright Transient Survey classifications

    NASA Astrophysics Data System (ADS)

    Graham, M. L.; Bellm, E.; Bektesevic, D.; Eadie, G.; Huppenkothen, D.; Davenport, J. R. A.; Fremling, C.; Sharma, Y.; Kulkarni, S. R.; Walters, R.; Blagorodnova, N.; Neill, J.; Miller, A. A.; Taddia, F.; Lunnan, R.; Taggart, K.; Perley, D. A.; Goobar, A.

    2018-06-01

    The Zwicky Transient Facility (ZTF; ATel #11266) Bright Transient Survey (BTS; ATel #11688) reports classifications of the following targets. Spectra have been obtained with the Dual Imaging Spectrograph (range 340-1000nm, spectral resolution R 1000) mounted on the 3.5m telescope at Apache Point Observatory, the Spectral Energy Distribution Machine (SEDM) (range 350-950nm, spectral resolution R 100) mounted on the Palomar 60-inch (P60) telescope (Blagorodnova et. al. 2018, PASP, 130, 5003), or the Andalucia Faint Object Spectrograph and Camera (ALFOSC) on the 2.5m Nordic Optical Telescope (NOT).

  5. Metastable Packaging For Transient Electronics

    DTIC Science & Technology

    2014-09-01

    dated 16 Jan 09. Report contains color. 14. ABSTRACT Metastable polymeric materials were synthesized, formulated with additives and microcapsules ...photoacid generation, thermal activation, and mechanical rupture of acid-filled microcapsules -- were investigated. 15. SUBJECT TERMS transient...carbonate sulfone) (PVBCS)... 11  3.3  Thermal and Mechanical Triggered Transience of Electronic Devices via Embedded Microcapsules

  6. Beitraege zur Astronomiegeschichte, Band 5 (Acta Historica Astronomiae Vol. 18)

    NASA Astrophysics Data System (ADS)

    Duerbeck, H. W.; Dick, W. R.; Hamel, J.

    2003-01-01

    The 18th volume of the Acta Historica Astronomiae is at the same time the sixth collection of essays on the history of astronomy ("Beitræge zur Astronomiegeschichte, Band 6"), edited by the historians of astronomy W.R. Dick (Potsdam) and J. Hamel (Berlin). Besides a few short notices and book reviews, the book contains eight major articles, which deal with astronomical topics covering the time from the 16th to the 19th centuries. The first article by Michael Weichenhan (Berlin) deals with "the invention of the disk-shaped earth: a chapter of Copernican apologetics". The author shows that the concept of a "disc-shaped Earth" was by no means widespread in the middle ages, but restricted to the father of the church Lactantius and some adherents. Nevertheless, it was used by adherents of Copernicus to show the absurd consequences of a strictly literal biblical interpretation -- here concerning the Earth's shape, disc versus sphere, there the geocentric versus the heliocentric system. This thorough philosophical study is followed by two very short articles. "The measuring accuracy of Tycho's large sextant" by Johann Wünsch investigates O-C values of planet-star distances, as based on Tycho's observations as published in the Historia Coelestis (a compilation, which is also based on Tycho's manuscripts, and published in Regensburg in 1672). The result is that standard deviations are 80 arcseconds for Saturn and 89 arcseconds for Jupiter and Mars, an unexpectedly poor result in view of the general opinion that Tycho was famous for his precision work. "The astronomer Christoph Grienberger and the Galilei trial" by Franz Daxecker deals with a Jesuit astronomer who was both the disciple and successor of the mathematician-astronomer Christopher Clavius at the Collegium Romanum. While he was inclined to Galilei early on, he was forced to propagate Aristotelian doctrine. The brief article is very concise, but extremely tiresome to read (3 pages of pure text are embellished by

  7. S2k-Leitlinie zum Gebrauch von Präparationen zur lokalen Anwendung auf der Haut (Topika).

    PubMed

    Wohlrab, Johannes; Staubach, Petra; Augustin, Matthias; Eisert, Lisa; Hünerbein, Andreas; Nast, Alexander; Reimann, Holger; Strömer, Klaus; Mahler, Vera

    2018-03-01

    Diese Leitlinie richtet sich an Assistenz- und Fachärzte der Dermatologie sowie an Kostenträger und politische Entscheidungsgremien. Die Leitlinie wurde im formellen Konsensusverfahren (S2k) von Dermatologen unter Einbindung von Apothekern erstellt. Die Leitlinie stellt allgemeine Aspekte der Pharmakokinetik sowie der regulatorischen Begrifflichkeiten dar. Es werden Empfehlungen zur Indikation von Magistralrezepturen sowie deren Qualitätssicherung gegeben. Die Bedeutung der galenischen Grundlagen und die Problematik bei einer Substitution gegeneinander verschiedener Grundlagen werden dargestellt. Die Leitlinie umfasst Kriterien zur Auswahl einer adäquaten Grundlage sowie spezifische Aspekte zur Therapieplanung. Die Leitlinie gibt Empfehlungen zum Management bei Unverträglichkeiten gegenüber Bestandteilen der Grundlagen oder Hilfsstoffe. © 2018 The Authors | Journal compilation © Blackwell Verlag GmbH, Berlin.

  8. Superresolution microscopy with transient binding.

    PubMed

    Molle, Julia; Raab, Mario; Holzmeister, Susanne; Schmitt-Monreal, Daniel; Grohmann, Dina; He, Zhike; Tinnefeld, Philip

    2016-06-01

    For single-molecule localization based superresolution, the concentration of fluorescent labels has to be thinned out. This is commonly achieved by photophysically or photochemically deactivating subsets of molecules. Alternatively, apparent switching of molecules can be achieved by transient binding of fluorescent labels. Here, a diffusing dye yields bright fluorescent spots when binding to the structure of interest. As the binding interaction is weak, the labeling is reversible and the dye ligand construct diffuses back into solution. This approach of achieving superresolution by transient binding (STB) is reviewed in this manuscript. Different realizations of STB are discussed and compared to other localization-based superresolution modalities. We propose the development of labeling strategies that will make STB a highly versatile tool for superresolution microscopy at highest resolution. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Towards traceable transient pressure metrology

    NASA Astrophysics Data System (ADS)

    Hanson, Edward; Olson, Douglas A.; Liu, Haijun; Ahmed, Zeeshan; Douglass, Kevin O.

    2018-04-01

    We describe our progress in developing the infrastructure for traceable transient measurements of pressure. Towards that end, we have built and characterized a dual diaphragm shock tube that allows us to achieve shock amplitude reproducibility of approximately 2.3% for shocks with Mach speeds ranging from 1.26-1.5. In this proof-of-concept study we use our shock tube to characterize the dynamic response of photonic sensors embedded in polydimethylsiloxane (PDMS), a material of choice for soft tissue phantoms. Our results indicate that the PDMS-embedded photonic sensors response to shock evolves over a tens to hundreds of microseconds time scale making it a useful system for studying transient pressures in soft tissue.

  10. Transient Effects in Turbulence Modelling.

    DTIC Science & Technology

    1979-12-01

    plenum region of a liquid-metal- cooled fast breeder reactor (LMFBR). The efficient heat transfer characteristics of liquid metal coolant, combined...Transients in Generalized Liquid-Metal Fast Breeder Reactor Outlet Plenums," Nuclear Technology, Vol. 44, July 1979, p. 210. 135 15. Lorenz, J. J., "MIX... Sodium Coolant in the Outlet Plenum of a Fast Nuclear Reactor ," Int. J. Heat Mass Transfer, Vol. 21, 1978, pp. 1565-1579. 19. Chen, Y. B., Golay, M. W

  11. Selection Dynamics in Transient Compartmentalization

    NASA Astrophysics Data System (ADS)

    Blokhuis, Alex; Lacoste, David; Nghe, Philippe; Peliti, Luca

    2018-04-01

    Transient compartments have been recently shown to be able to maintain functional replicators in the context of prebiotic studies. Here, we show that a broad class of selection dynamics is able to achieve this goal. We identify two key parameters, the relative amplification of nonactive replicators (parasites) and the size of compartments. These parameters account for competition and diversity, and the results are relevant to similar multilevel selection problems, such as those found in virus-host ecology and trait group selection.

  12. Radio Counterparts to SXR Transients

    NASA Astrophysics Data System (ADS)

    Gary, D. E.

    1999-12-01

    By now several studies have been done on small-scale brightenings seen at radio, UV, EUV, and soft X-ray wavelengths. These are to be reviewed by Kundu in these proceedings. In this talk we concentrate on the radio counterpart of a particular type of brightening---the soft X-ray transient brightenings of Shimizu. These brightenings are associated with active regions, and a study of radio counterparts by White et al. (1995) using Nobeyama data found an excellent correspondence between the 17 GHz and SXR brightenings, both spatially and temporally. However, this study found that both the SXR and microwave emissions could be satisfactorily explained as purely thermal emission, and a search of BATSE hard X-ray data showed no nonthermal counterpart. White et al. (1995) were forced to conclude that the events may be different from flares. A more sensitive search for nonthermal emission was needed, in particular using lower frequency microwaves where the influence of nonthermal electrons would be more easily detected. Gary, Hartl and Shimizu (1997) found 34 SXR transient brightenings over a 10-day period in May 1992, for which OVRO (1-18 GHz) total power data were available. A comparison of the data showed a number of clear nonthermal signatures. In addition, one of the events was seen in the lowest energy (6-9.3 keV) channel of the BATSE SPEC detector, suggesting a connection between the microflares discovered in hard X-rays by Lin et al. (1984). The evidence that SXR transient brightenings are microflares is reviewed in this talk. We also attempt to place other small-scale brightenings in context with regard to SXR transient brightenings and microflares.

  13. Novel Active Transient Cooling Systems

    DTIC Science & Technology

    2010-05-04

    NOVEL ACTIVE TRANSIENT COOLING SYSTEMS PI: R.V. Ramanujan Co-PI: P. Keblinski*, G. Ramanath*, E.V. Sampathkumaran^ School of Materials...PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Raju Ramanujan 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND...Report (SAR) 18. NUMBER OF PAGES 13 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c . THIS PAGE unclassified

  14. Asiago spectroscopic classification of six optical transients

    NASA Astrophysics Data System (ADS)

    Tomasella, L.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Ochner, P.; Pastorello, A.; Tartaglia, L.; Terreran, G.; Turatto, M.

    2015-01-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic observation of the following transients. Targets were supplied by the Astronomy Section of the Rochester Academy of Sciences (arXiv:1103.5165), the CBAT Transient Objects Confirmation Page (TOCP) and the Gaia Photometric Science Alerts (validation phase).

  15. Adaptive sampling of AEM transients

    NASA Astrophysics Data System (ADS)

    Di Massa, Domenico; Florio, Giovanni; Viezzoli, Andrea

    2016-02-01

    This paper focuses on the sampling of the electromagnetic transient as acquired by airborne time-domain electromagnetic (TDEM) systems. Typically, the sampling of the electromagnetic transient is done using a fixed number of gates whose width grows logarithmically (log-gating). The log-gating has two main benefits: improving the signal to noise (S/N) ratio at late times, when the electromagnetic signal has amplitudes equal or lower than the natural background noise, and ensuring a good resolution at the early times. However, as a result of fixed time gates, the conventional log-gating does not consider any geological variations in the surveyed area, nor the possibly varying characteristics of the measured signal. We show, using synthetic models, how a different, flexible sampling scheme can increase the resolution of resistivity models. We propose a new sampling method, which adapts the gating on the base of the slope variations in the electromagnetic (EM) transient. The use of such an alternative sampling scheme aims to get more accurate inverse models by extracting the geoelectrical information from the measured data in an optimal way.

  16. Transient virulence of emerging pathogens.

    PubMed

    Bolker, Benjamin M; Nanda, Arjun; Shah, Dharmini

    2010-05-06

    Should emerging pathogens be unusually virulent? If so, why? Existing theories of virulence evolution based on a tradeoff between high transmission rates and long infectious periods imply that epidemic growth conditions will select for higher virulence, possibly leading to a transient peak in virulence near the beginning of an epidemic. This transient selection could lead to high virulence in emerging pathogens. Using a simple model of the epidemiological and evolutionary dynamics of emerging pathogens, along with rough estimates of parameters for pathogens such as severe acute respiratory syndrome, West Nile virus and myxomatosis, we estimated the potential magnitude and timing of such transient virulence peaks. Pathogens that are moderately evolvable, highly transmissible, and highly virulent at equilibrium could briefly double their virulence during an epidemic; thus, epidemic-phase selection could contribute significantly to the virulence of emerging pathogens. In order to further assess the potential significance of this mechanism, we bring together data from the literature for the shapes of tradeoff curves for several pathogens (myxomatosis, HIV, and a parasite of Daphnia) and the level of genetic variation for virulence for one (myxomatosis). We discuss the need for better data on tradeoff curves and genetic variance in order to evaluate the plausibility of various scenarios of virulence evolution.

  17. Transient virulence of emerging pathogens

    PubMed Central

    Bolker, Benjamin M.; Nanda, Arjun; Shah, Dharmini

    2010-01-01

    Should emerging pathogens be unusually virulent? If so, why? Existing theories of virulence evolution based on a tradeoff between high transmission rates and long infectious periods imply that epidemic growth conditions will select for higher virulence, possibly leading to a transient peak in virulence near the beginning of an epidemic. This transient selection could lead to high virulence in emerging pathogens. Using a simple model of the epidemiological and evolutionary dynamics of emerging pathogens, along with rough estimates of parameters for pathogens such as severe acute respiratory syndrome, West Nile virus and myxomatosis, we estimated the potential magnitude and timing of such transient virulence peaks. Pathogens that are moderately evolvable, highly transmissible, and highly virulent at equilibrium could briefly double their virulence during an epidemic; thus, epidemic-phase selection could contribute significantly to the virulence of emerging pathogens. In order to further assess the potential significance of this mechanism, we bring together data from the literature for the shapes of tradeoff curves for several pathogens (myxomatosis, HIV, and a parasite of Daphnia) and the level of genetic variation for virulence for one (myxomatosis). We discuss the need for better data on tradeoff curves and genetic variance in order to evaluate the plausibility of various scenarios of virulence evolution. PMID:19864267

  18. Transient combustion in hybrid rockets

    NASA Astrophysics Data System (ADS)

    Karabeyoglu, Mustafa Arif

    1998-09-01

    Hybrid rockets regained interest recently as an alternative chemical propulsion system due to their advantages over the solid and liquid systems that are currently in use. Development efforts on hybrids revealed two important problem areas: (1) low frequency instabilities and (2) slow transient response. Both of these are closely related to the transient behavior which is a poorly understood aspect of hybrid operation. This thesis is mainly involved with a theoretical study of transient combustion in hybrid rockets. We follow the methodology of identifying and modeling the subsystems of the motor such as the thermal lags in the solid, boundary layer combustion and chamber gasdynamics from a dynamic point of view. We begin with the thermal lag in the solid which yield the regression rate for any given wall heat flux variation. Interesting phenomena such as overshooting during throttling and the amplification and phase lead regions in the frequency domain are discovered. Later we develop a quasi-steady transient hybrid combustion model supported with time delays for the boundary layer processes. This is integrated with the thermal lag system to obtain the thermal combustion (TC) coupled response. The TC coupled system with positive delays generated low frequency instabilities. The scaling of the instabilities are in good agreement with actual motor test data. Finally, we formulate a gasdynamic model for the hybrid chamber which successfully resolves the filling/emptying and longitudinal acoustic behavior of the motor. The TC coupled system is later integrated to the gasdynamic model to obtain the overall response (TCG coupled system) of gaseous oxidizer motors with stiff feed systems. Low frequency instabilities were also encountered for the TCG coupled system. Apart from the transient investigations, the regression rate behavior of liquefying hybrid propellants such as solid cryogenic materials are also studied. The theory is based on the possibility of enhancement

  19. The Zinc-Responsive Regulator Zur Controls a Zinc Uptake System and Some Ribosomal Proteins in Streptomyces coelicolor A3(2)▿

    PubMed Central

    Shin, Jung-Ho; Oh, So-Young; Kim, Soon-Jong; Roe, Jung-Hye

    2007-01-01

    In various bacteria, Zur, a zinc-specific regulator of the Fur family, regulates genes for zinc transport systems to maintain zinc homeostasis. It has also been suggested that Zur controls zinc mobilization by regulating some ribosomal proteins. The antibiotic-producing soil bacterium Streptomyces coelicolor contains four genes for Fur family regulators, and one (named zur) is located downstream of the znuACB operon encoding a putative zinc uptake transporter. We found that zinc specifically repressed the level of znuA transcripts and that this level was derepressed in a Δzur mutant. Purified Zur existing as homodimers bound to the znuA promoter region in the presence of zinc, confirming the role of Zur as a zinc-responsive repressor. We analyzed transcripts for paralogous forms of ribosomal proteins L31 (RpmE1 and RpmE2) and L33 (RpmG2 and RpmG3) for their dependence on Zur and found that RpmE2 and RpmG2 with no zinc-binding motif of conserved cysteines (C's) were negatively regulated by Zur. C-negative RpmG3 and C-positive RpmE1 were not regulated by Zur. Instead, they were regulated by the sigma factor σR as predicted from their promoter sequences. The rpmE1 and rpmG3 genes were partially induced by EDTA in a manner dependent on σR, suggesting that zinc depletion may stimulate the σR regulatory system. This finding reflects a link between thiol-oxidizing stress and zinc depletion. We determined the Zur-binding sites within znuA and rpmG2 promoter regions by footprinting analyses and identified a consensus inverted repeat sequence (TGaaAatgatTttCA, where uppercase letters represent the nucleotides common to all sites analyzed). This sequence closely matches that for mycobacterial Zur and allows the prediction of more genes in the Zur regulon. PMID:17416659

  20. Transient hyperthyroidism of hyperemesis gravidarum.

    PubMed

    Tan, Jackie Y L; Loh, Keh Chuan; Yeo, George S H; Chee, Yam Cheng

    2002-06-01

    To characterise the clinical, biochemical and thyroid antibody profile in women with transient hyperthyroidism of hyperemesis gravidarum. Prospective observational study. Hospital inpatient gynaecological ward. Women admitted with hyperemesis gravidarum and found to have hyperthyroidism. Fifty-three women were admitted with hyperemesis gravidarum and were found to have hyperthyroidism. Each woman was examined for clinical signs of thyroid disease and underwent investigations including urea, creatinine, electrolytes, liver function test, thyroid antibody profile and serial thyroid function test until normalisation. Gestation at which thyroid function normalised, clinical and thyroid antibody profile and pregnancy outcome (birthweight, gestation at delivery and Apgar score at 5 minutes). Full data were available for 44 women. Free T4 levels normalised by 15 weeks of gestation in the 39 women with transient hyperthyroidism while TSH remained suppressed until 19 weeks of gestation. None of these women were clinically hyperthyroid. Thyroid antibodies were not found in most of them. Median birthweight in the infants of mothers who experienced weight loss of > 5% of their pre-pregnancy weight was lower compared with those of women who did not (P = 0.093). Five women were diagnosed with Graves' disease based on clinical features and thyroid antibody profile. In transient hyperthyroidism of hyperemesis gravidarum, thyroid function normalises by the middle of the second trimester without anti-thyroid treatment. Clinically overt hyperthyroidism and thyroid antibodies are usually absent. Apart from a non-significant trend towards lower birthweights in the infants of mothers who experienced significant weight loss, pregnancy outcome was generally good. Routine assessment of thyroid function is unnecessary for women with hyperemesis gravidarum in the absence of any clinical features of hyperthyroidism.

  1. Von neuen Geschäftsideen zur gelebten Digitalisierung in Utility 4.0 - das Integrierte Geschäftsmodell

    NASA Astrophysics Data System (ADS)

    Doleski, Oliver D.

    Die Energiewirtschaft benötigt neue, digitale Geschäftsmodelle. Gegenwärtig folgt auf Liberalisierung und Energiewende die nächste Stufe einer weitreichenden Bereinigung des Versorgungsmarktes. Digitalisierung und Dezentralisierung sind heute in aller Munde und verlangen nach neuen Produkten und Dienstleistungen. Dabei wirken die immensen Herausforderungen einer digitalen Energiewelt wie Beschleuniger für die Transformation im Versorgungssektor und tragen damit zur breiten Etablierung von Utilities 4.0 bei. Dieser Entwicklungsprozess vollzieht sich mithilfe unterschiedlicher Methoden zur Realisierung neuer Geschäftsideen. Allerdings greifen die gängigen Konzepte zur Entwicklung von Geschäftsmodellen gerade im Hinblick auf die Berücksichtigung komplexer, unbeständiger Rahmenbedingungen und spezifischer Anforderungen der digitalen Energiewelt mitunter zu kurz. Vor diesem Hintergrund wird das auf dem ganzheitlichen St. Galler Management-Konzept beruhende Integrierte Geschäftsmodell iOcTen als geeignetes Instrumentarium zur Geschäftsmodellentwicklung vorgestellt. Neben der Modellbeschreibung unterstützt ein intuitiv verständlicher Leitfaden den Praktiker bei der Transformation vom klassischen Versorgungsunternehmen zum digitalen Energiedienstleistungsunternehmen.

  2. The Zwicky Transient Facility Camera

    NASA Astrophysics Data System (ADS)

    Dekany, Richard; Smith, Roger M.; Belicki, Justin; Delacroix, Alexandre; Duggan, Gina; Feeney, Michael; Hale, David; Kaye, Stephen; Milburn, Jennifer; Murphy, Patrick; Porter, Michael; Reiley, Daniel J.; Riddle, Reed L.; Rodriguez, Hector; Bellm, Eric C.

    2016-08-01

    The Zwicky Transient Facility Camera (ZTFC) is a key element of the ZTF Observing System, the integrated system of optoelectromechanical instrumentation tasked to acquire the wide-field, high-cadence time-domain astronomical data at the heart of the Zwicky Transient Facility. The ZTFC consists of a compact cryostat with large vacuum window protecting a mosaic of 16 large, wafer-scale science CCDs and 4 smaller guide/focus CCDs, a sophisticated vacuum interface board which carries data as electrical signals out of the cryostat, an electromechanical window frame for securing externally inserted optical filter selections, and associated cryo-thermal/vacuum system support elements. The ZTFC provides an instantaneous 47 deg2 field of view, limited by primary mirror vignetting in its Schmidt telescope prime focus configuration. We report here on the design and performance of the ZTF CCD camera cryostat and report results from extensive Joule-Thompson cryocooler tests that may be of broad interest to the instrumentation community.

  3. Transient electromagnetic sounding for groundwater

    Fitterman, David V.; Stewart, Mark T.

    1986-01-01

    The feasibility of using the transient electromagnetic sounding (TS or TDEM) method for groundwater exploration can be studied by means of numerical models. As examples of its applicability to groundwater exploration, we study four groundwater exploration problems: (1) mapping of alluvial fill and gravel zones over bedrock; (2) mapping of sand and gravel lenses in till; (3) detection of salt or brackish water interfaces in freshwater aquifers; and (4) determination of hydrostratigraphy. These groundwater problems require determination of the depth to bedrock; location of resistive, high‐porosity zones associated with fresh water; determination of formation resistivity to assess water quality; and determination of lithology and geometry, respectively. The TS method is best suited for locating conductive targets, and has very good vertical resolution. Unlike other sounding techniques where the receiver‐transmitter array must be expanded to sound more deeply, the depth of investigation for the TS method is a function of the length of time the transient is recorded. Present equipment limitations require that exploration targets with resistivities of 50 Ω ⋅ m or more be at least 50 m deep to determine their resistivity. The maximum depth of exploration is controlled by the geoelectrical section and background electromagnetic (EM) noise. For a particular exploration problem, numerical studies are recommended to determine if the target is detectable.

  4. The course of transient hypochondriasis.

    PubMed

    Barsky, A J; Cleary, P D; Sarnie, M K; Klerman, G L

    1993-03-01

    This study examined the longitudinal course of patients known to have had a previous episode of transient hypochondriasis. Twenty-two transiently hypochondriacal patients and 24 nonhypochondriacal patients from the same general medical clinic were reexamined after an average of 22 months with the use of self-report questionnaires, structured diagnostic interviews, and medical record review. The hypochondriacal patients continued to manifest significantly more hypochondriacal symptoms, more somatization, and more psychopathological symptoms at follow-up. They also reported significantly more amplification of bodily sensations and more functional disability and utilized more medical care. These differences persisted after control for differences in medical morbidity and marital status. Only one hypochondriacal patient, however, had a DSM-III-R diagnosis of hypochondriasis at follow-up. Multivariate analyses revealed that the only significant predictors of hypochondriacal symptoms at follow-up were hypochondriacal symptoms and the tendency to amplify bodily sensations at the baseline evaluation. Hypochondriacal symptoms appear to have some temporal stability: patients who experienced hypochondriacal episodes at the beginning of the study were significantly more hypochondriacal 2 years later than comparison patients. They were not, however, any more likely to develop DSM-III-R-defined hypochondriasis. Thus, hypochondriacal symptoms may be distinct from the axis I disorder. The data are also compatible with the hypothesis that preexisting amplification of bodily sensations is an important predictor of subsequent hypochondriacal symptoms.

  5. Transient Science from Diverse Surveys

    NASA Astrophysics Data System (ADS)

    Mahabal, A.; Crichton, D.; Djorgovski, S. G.; Donalek, C.; Drake, A.; Graham, M.; Law, E.

    2016-12-01

    Over the last several years we have moved closer to being able to make digital movies of the non-static sky with wide-field synoptic telescopes operating at a variety of depths, resolutions, and wavelengths. For optimal combined use of these datasets, it is crucial that they speak and understand the same language and are thus interoperable. Initial steps towards such interoperability (e.g. the footprint service) were taken during the two five-year Virtual Observatory projects viz. National Virtual Observatory (NVO), and later Virtual Astronomical Observatory (VAO). Now with far bigger datasets and in an era of resource excess thanks to the cloud-based workflows, we show how the movement of data and of resources is required - rather than just one or the other - to combine diverse datasets for applications such as real-time astronomical transient characterization. Taking the specific example of ElectroMagnetic (EM) follow-up of Gravitational Wave events and EM transients (such as CRTS but also other optical and non-optical surveys), we discuss the requirements for rapid and flexible response. We show how the same methodology is applicable to Earth Science data with its datasets differing in spatial and temporal resolution as well as differing time-spans.

  6. Transient trimethylaminuria related to menstruation

    PubMed Central

    Shimizu, Makiko; Cashman, John R; Yamazaki, Hiroshi

    2007-01-01

    Background Trimethylaminuria, or fish odor syndrome, includes a transient or mild malodor caused by an excessive amount of malodorous trimethylamine as a result of body secretions. Herein, we describe data to support the proposal that menses can be an additional factor causing transient trimethylaminuria in self-reported subjects suffering from malodor and even in healthy women harboring functionally active flavin-containing monooxygenase 3 (FMO3). Methods FMO3 metabolic capacity (conversion of trimethylamine to trimethylamine N-oxide) was defined as the urinary ratio of trimethylamine N-oxide to total trimethylamine. Results Self-reported Case (A) that was homozygous for inactive Arg500stop FMO3, showed decreased metabolic capacity of FMO3 (i.e., ~10% the unaffected metabolic capacity) during 120 days of observation. For Case (B) that was homozygous for common [Glu158Lys; Glu308Gly] FMO3 polymorphisms, metabolic capacity of FMO3 was almost ~90%, except for a few days surrounding menstruation showing < 40% metabolic capacity. In comparison, three healthy control subjects that harbored heterozygous polymorphisms for [Glu158Lys; Glu308Gly] FMO3 or homozygous for wild FMO3 showed normal (> 90%) metabolic capacity, however, on days around menstruation the FMO3 metabolic capacity was decreased to ~60–70%. Conclusion Together, these results indicate that abnormal FMO3 capacity is caused by menstruation particularly in the presence, in homozygous form, of mild genetic variants such as [Glu158Lys; Glu308Gly] that cause a reduced FMO3 function. PMID:17257434

  7. Discovery and Classification of ZTF Transients

    NASA Astrophysics Data System (ADS)

    Lunnan, Ragnhild; Taddia, Francesco; Sollerman, Jesper; Barbarino, Cristina; Goobar, Ariel; Fremling, Christoffer; Kasliwal, Mansi; Cannella, Chris; Blagorodnova, Nadejda; Neill, J. Don; Walters, Richard; Ho, Anna; Yan, Lin; Burdge, Kevin; Schulze, Steve; Yaron, Ofer; Gal-Yam, Avishay; Yang, Yi; Graham, Melissa; Golkhou, V. Zach; Bellm, Eric; Parley, Daniel; Zwicky Transient Facility Collaboration

    2018-04-01

    We report spectroscopic classifications of 17 transients discovered by the Zwicky Transient Facility (ZTF; ATel #11266) during science validation. Additional classifications of older transients have been reported to and are publicly available on the TNS. Spectra were obtained with DBSP at the Palomar 200-in Hale Telescope, with DIS at the ARC 3.5m telescope at Apache Point Observatory, and with SPRAT at Liverpool Telescope.

  8. Adaptation to transient postural perturbations

    NASA Technical Reports Server (NTRS)

    Andres, Robert O.

    1992-01-01

    This research was first proposed in May, 1986, to focus on some of the problems encountered in the analysis of postural responses gathered from crewmembers. The ultimate driving force behind this line of research was the desire to treat, predict, or explain 'Space Adaptation Syndrome' (SAS) and hence circumvent any adverse effects of space motion sickness on crewmember performance. The aim of this project was to develop an easily implemented analysis of the transient responses to platform translation that can be elicited with a protocol designed to force sensorimotor reorganization, utilizing statistically reliable criterion measures. This report will present: (1) a summary of the activity that took place in each of the three funded years of the project; (2) discussion of experimental results and their implications for future research; and (3) a list of presentations and publications resulting from this project.

  9. Transient global amnesia: current perspectives

    PubMed Central

    Spiegel, David R; Smith, Justin; Wade, Ryan R; Cherukuru, Nithya; Ursani, Aneel; Dobruskina, Yuliya; Crist, Taylor; Busch, Robert F; Dhanani, Rahim M; Dreyer, Nicholas

    2017-01-01

    Transient global amnesia (TGA) is a clinical syndrome characterized by the sudden onset of an extraordinarily large reduction of anterograde and a somewhat milder reduction of retrograde episodic long-term memory. Additionally, executive functions are described as diminished. Although it is suggested that various factors, such as migraine, focal ischemia, venous flow abnormalities, and epileptic phenomena, are involved in the pathophysiology and differential diagnosis of TGA, the factors triggering the emergence of these lesions are still elusive. Recent data suggest that the vulnerability of CA1 neurons to metabolic stress plays a pivotal part in the pathophysiological cascade, leading to an impairment of hippocampal function during TGA. In this review, we discuss clinical aspects, new imaging findings, and recent clinical–epidemiological data with regard to the phenotype, functional anatomy, and putative cellular mechanisms of TGA. PMID:29123402

  10. Stability Test for Transient-Temperature Calculations

    NASA Technical Reports Server (NTRS)

    Campbell, W.

    1984-01-01

    Graphical test helps assure numerical stability of calculations of transient temperature or diffusion in composite medium. Rectangular grid forms basis of two-dimensional finite-difference model for heat conduction or other diffusion like phenomena. Model enables calculation of transient heat transfer among up to four different materials that meet at grid point.

  11. SCAT Classification of 4 Optical Transients

    NASA Astrophysics Data System (ADS)

    Tucker, Michael A.; Rowan, Dominick M.; Shappee, Benjamin J.; Dong, Subo; Bose, Subhash; Stanek, K. Z.

    2018-06-01

    The Spectral Classification of Astronomical Transients (SCAT) survey (ATel #11444) presents the classification of 4 optical transients. We report optical spectroscopy (330-970nm) taken with the University of Hawaii 88-inch (UH88) telescope using the SuperNova Integral Field Spectrograph (SNIFS).

  12. Transient abnormal Q waves during exercise electrocardiography

    PubMed Central

    Alameddine, F F; Zafari, A M

    2004-01-01

    Myocardial ischaemia during exercise electrocardiography is usually manifested by ST segment depression or elevation. Transient abnormal Q waves are rare, as Q waves indicate an old myocardial infarction. The case of a patient with exercise induced transient abnormal Q waves is reported. The potential mechanisms involved in the development of such an abnormality and its clinical implications are discussed. PMID:14676264

  13. Asiago spectroscopic classification of 3 transients

    NASA Astrophysics Data System (ADS)

    Tomasella, L.; Benetti, S.; Cappellaro, E.; Turatto, M.

    2018-01-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of AT 2018eq discovered by R. Belligoli (ISSP) in the direction of M31; PS18bq (AT2018bi) discovered by J. Grzegorzek and Pan-STARRS1 in UGC1791; and AT2018C (= Gaia18aak), a blue hostless transient discovered by Gaia.

  14. Versuche zur Gewinnung von katalytischen Antikörpern zur Hydrolyse von Arylcarbamaten und Arylharnstoffen. (English Title: Attempts to produce catalytic antibodies for hydrolysis of arylcarbamates and arylureas)

    NASA Astrophysics Data System (ADS)

    Werner, Deljana

    2002-05-01

    Im Rahmen dieser Arbeit gelang es, katalytische Antikörper zur Hydrolyse von Benzylphenylcarbamaten sowie zahlreiche monoklonale Antikörper gegen Haptene herzustellen. Es wurden verschiedene Hapten-Protein-Konjugate unter Verwendung unterschiedlicher Kopplungsmethoden hergestellt und charakterisiert. Zur Generierung der hydrolytisch aktiven Antikörper wurden Inzuchtmäuse mit KLH-Konjugaten von 4 Übergangszustandsanaloga (ÜZA) immunisiert. Mit Hilfe der Hybridomtechnik wurden verschiedene monoklonale Antikörper gegen diese ÜZA gewonnen. Dabei wurden sowohl verschiedene Immunisierungsschemata als auch verschiedene Inzuchtmausstämme und Fusionstechniken verwendet. Insgesamt wurden 32 monoklonale Antikörper gegen die verwendeten ÜZA selektiert. Diese Antikörper wurden in groen Mengen hergestellt und gereinigt. Zum Nachweis der Antikörper-vermittelten Katalyse wurden verschiedene Methoden entwickelt und eingesetzt, darunter immunologische Nachweismethoden mit Anti-Substrat- und Anti-Produkt-Antikörpern und eine photometrische Methode mit Dimethylaminozimtaldehyd. Der Nachweis der hydrolytischen Aktivität gelang mit Hilfe eines Enzymsensors, basierend auf immobilisierter Tyrosinase. Die Antikörper N1-BC1-D11, N1-FA7-C4, N1-FA7-D12 und R3-LG2-F9 hydrolysierten die Benzylphenylcarbamate POCc18, POCc19 und Substanz 27. Der Nachweis der hydrolytischen Aktivität dieser Antikörper gelang auch mit Hilfe der HPLC. Der katalytische Antikörper N1-BC1-D11 wurde kinetisch und thermodynamisch untersucht. Es wurde eine Michaelis-Menten-Kinetik mit Km von 210 µM, vmax von 3 mM/min und kcat von 222 min-1 beobachtet. Diese Werte korrelieren mit den Werten der wenigen bekannten Diphenylcarbamat-spaltenden Abzyme. Die Beschleunigungsrate des Antikörpers N1-BC1-D11 betrug 10. Das ÜZA Hei3 hemmte die hydrolytische Aktivität. Dies beweist, dass die Hydrolyse in der Antigenbindungsstelle stattfindet. Weiter wurde zwischen der Antikörperkonzentration und der

  15. Characterizing transient noise in the LIGO detectors.

    PubMed

    Nuttall, L K

    2018-05-28

    Data from the LIGO detectors typically contain many non-Gaussian noise transients which arise due to instrumental and environmental conditions. These non-Gaussian transients can be an issue for the modelled and unmodelled transient gravitational-wave searches, as they can mask or mimic a true signal. Data quality can change quite rapidly, making it imperative to track and find new sources of transient noise so that data are minimally contaminated. Several examples of transient noise and the tools used to track them are presented. These instances serve to highlight the diverse range of noise sources present at the LIGO detectors during their second observing run.This article is part of a discussion meeting issue 'The promises of gravitational-wave astronomy'. © 2018 The Author(s).

  16. Characterizing transient noise in the LIGO detectors

    NASA Astrophysics Data System (ADS)

    Nuttall, L. K.

    2018-05-01

    Data from the LIGO detectors typically contain many non-Gaussian noise transients which arise due to instrumental and environmental conditions. These non-Gaussian transients can be an issue for the modelled and unmodelled transient gravitational-wave searches, as they can mask or mimic a true signal. Data quality can change quite rapidly, making it imperative to track and find new sources of transient noise so that data are minimally contaminated. Several examples of transient noise and the tools used to track them are presented. These instances serve to highlight the diverse range of noise sources present at the LIGO detectors during their second observing run. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.

  17. Machine Learning for Zwicky Transient Facility

    NASA Astrophysics Data System (ADS)

    Mahabal, Ashish; Zwicky Transient Facility, Catalina Real-Time Transient Survey

    2018-01-01

    The Zwicky Transient Facility (ZTF) will operate from 2018 to 2020 covering the accessible sky with its large 47 square degree camera. The transient detection rate is expected to be about a million per night. ZTF is thus a perfect LSST prototype. The big difference is that all of the ZTF transients can be followed up by 4- to 8-m class telescopes. Given the large numbers, using human scanners for separating the genuine transients from artifacts is out of question. For that first step as well as for classifying the transients with minimal follow-up requires machine learning. We describe the tools and plans to take on this task using follow-up facilities, and knowledge gained from archival datasets.

  18. Thalamic Amnesia Mimicking Transient Global Amnesia.

    PubMed

    Giannantoni, Nadia M; Lacidogna, Giordano; Broccolini, Aldobrando; Pilato, Fabio; Profice, Paolo; Morosetti, Roberta; Caliandro, Pietro; Gambassi, Giovanni; Della Marca, Giacomo; Frisullo, Giovanni

    2015-06-01

    Transient global amnesia is a benign syndrome and one of the most frequent discharges from the emergency department that can hardly be distinguished from other mimicking diseases. No consensus in the evaluation of transient global amnesia has yet been found in the emergency setting. We describe a 69-year-old woman who presented to our emergency department with an abrupt onset of anterograde amnesia, preceded by a similar amnesic episode misinterpreted as transient global amnesia. Neuroradiologic, neuropsychological, and neurophysiological evaluations supported the diagnosis of vascular thalamic amnesia. We report a patient who clinically fulfilled transient global amnesia's criteria and in whom nevertheless was disclosed a thalamic ischemic lesion on neuroimaging.This case report highlights the importance of performing neuroradiologic screening in the emergency department even when clinical history and physical findings are highly suggestive for transient global amnesia.

  19. Energetic ion leakage from foreshock transient cores

    NASA Astrophysics Data System (ADS)

    Liu, Terry Z.; Angelopoulos, Vassilis; Hietala, Heli

    2017-07-01

    Earth's foreshock is filled with backstreaming particles that can interact with the ambient solar wind and its discontinuities to form foreshock transients. Many foreshock transients have a core with low dynamic pressure that can significantly perturb the bow shock and the magnetosphere-ionosphere system. Foreshock transients have also been recently recognized as sites of particle acceleration, which may be important for seeding the parent shock with energetic particles. A relevant step of this seeding would be energetic ion leakage into the surrounding foreshock environment. On the other hand, such leakage would also suppress the energetic particle flux contrast across foreshock transients' boundaries masking their perceived contribution to ion energization. To further examine this hypothesis of ion leakage, we report on multipoint case studies of three foreshock transient events selected from a large database. The cases were selected to exemplify, in increasing complexity, the nature and consequences of energetic ion leakage. Ion energy dispersion, observed upstream and/or downstream of the foreshock transients, is explained with a simple, ballistic model of ions leaking from the foreshock transients. Larger energies are required for leaked ions to reach the spacecraft as the distance between the transient and spacecraft increases. Our model, which explains well the observed ion energy dispersion and velocity distributions, can also be used to reveal the shape of the foreshock transients in three dimensions. Our results suggest that ion leakage from foreshock transient cores needs to be accounted for both in statistical studies and in global models of ion acceleration under quasi-parallel foreshock conditions.

  20. Transient shocks beyond the heliopause

    SciT

    Fermo, R. L.; Pogorelov, N. V.; Burlaga, L. F.

    The heliopause is a rich, dynamic surface affected by the time-dependent solar wind. Stream interactions due to coronal mass ejections (CMEs), corotating interaction regions (CIRs), and other transient phenomena are known to merge producing global merged interaction regions (GMIRs). Numerical simulations of the solar wind interaction with the local interstellar medium (LISM) show that GMIRs, as well other time-dependent structures in the solar wind, may produce compression/rarefaction waves and shocks in the LISM behind the heliopause. These shocks may initiate wave activity observed by the Voyager spacecraft. The magnetometer onboard Voyager 1 indeed observed a few structures that may bemore » interpreted as shocks. We present numerical simulations of such shocks in the year of 2000, when both Voyager spacecraft were in the supersonic solar wind region, and in 2012, when Voyager 1 observed traveling shocks. In the former case, Voyager observations themselves provide time- dependent boundary conditions in the solar wind. In the latter case, we use OMNI data at 1 AU to analyze the plasma and magnetic field behavior after Voyager 1 crossed the heliospheric boundary. Numerical results are compared with spacecraft observations.« less

  1. Transient shocks beyond the heliopause

    DOE PAGES

    Fermo, R. L.; Pogorelov, N. V.; Burlaga, L. F.

    2015-09-30

    The heliopause is a rich, dynamic surface affected by the time-dependent solar wind. Stream interactions due to coronal mass ejections (CMEs), corotating interaction regions (CIRs), and other transient phenomena are known to merge producing global merged interaction regions (GMIRs). Numerical simulations of the solar wind interaction with the local interstellar medium (LISM) show that GMIRs, as well other time-dependent structures in the solar wind, may produce compression/rarefaction waves and shocks in the LISM behind the heliopause. These shocks may initiate wave activity observed by the Voyager spacecraft. The magnetometer onboard Voyager 1 indeed observed a few structures that may bemore » interpreted as shocks. We present numerical simulations of such shocks in the year of 2000, when both Voyager spacecraft were in the supersonic solar wind region, and in 2012, when Voyager 1 observed traveling shocks. In the former case, Voyager observations themselves provide time- dependent boundary conditions in the solar wind. In the latter case, we use OMNI data at 1 AU to analyze the plasma and magnetic field behavior after Voyager 1 crossed the heliospheric boundary. Numerical results are compared with spacecraft observations.« less

  2. POET: POlarimeters for Energetic Transients

    NASA Technical Reports Server (NTRS)

    Hill, J. E.; McConnell, M. L.; Bloser, P.; Legere, J.; Macri, J.; Ryan, J.; Barthelmy, S.; Angelini, L.; Sakamoto, T.; Black, J. K.; hide

    2008-01-01

    POET (Polarimeters for Energetic Transients) is a Small Explorer mission concept proposed to NASA in January 2008. The principal scientific goal of POET is to measure GRB polarization between 2 and 500 keV. The payload consists of two wide FoV instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2-15 keV and a high energy polarimeter (Gamma-Ray Polarimeter Experiment - GRAPE) that will measure polarization in the 60-500 keV energy range. Spectra will be measured from 2 keV up to 1 MeV. The POET spacecraft provides a zenith-pointed platform for maximizing the exposure to deep space. Spacecraft rotation will provide a means of effectively dealing with systematics in the polarization response. POET will provide sufficient sensitivity and sky coverage to measure statistically significant polarization for up to 100 GRBs in a two-year mission. Polarization data will also be obtained for solar flares, pulsars and other sources of astronomical interest.

  3. Transient thermohydraulic heat pipe modeling

    NASA Astrophysics Data System (ADS)

    Hall, Michael L.; Doster, Joseph M.

    Many space based reactor designs employ heat pipes as a means of conveying heat. In these designs, thermal radiation is the principle means for rejecting waste heat from the reactor system, making it desirable to operate at high temperatures. Lithium is generally the working fluid of choice as it undergoes a liquid-vapor transformation at the preferred operating temperature. The nature of remote startup, restart, and reaction to threats necessitates an accurate, detailed transient model of the heat pipe operation. A model is outlined of the vapor core region of the heat pipe which is part of a large model of the entire heat pipe thermal response. The vapor core is modeled using the area averaged Navier-Stokes equations in one dimension, which take into account the effects of mass, energy and momentum transfer. The core model is single phase (gaseous), but contains two components: lithium gas and a noncondensible vapor. The vapor core model consists of the continuity equations for the mixture and noncondensible, as well as mixture equations for internal energy and momentum.

  4. Transient liquid phase ceramic bonding

    DOEpatents

    Glaeser, Andreas M.

    1994-01-01

    Ceramics are joined to themselves or to metals using a transient liquid phase method employing three layers, one of which is a refractory metal, ceramic or alloy. The refractory layer is placed between two metal layers, each of which has a lower melting point than the refractory layer. The three layers are pressed between the two articles to be bonded to form an assembly. The assembly is heated to a bonding temperature at which the refractory layer remains solid, but the two metal layers melt to form a liquid. The refractory layer reacts with the surrounding liquid and a single solid bonding layer is eventually formed. The layers may be designed to react completely with each other and form refractory intermetallic bonding layers. Impurities incorporated into the refractory metal may react with the metal layers to form refractory compounds. Another method for joining ceramic articles employs a ceramic interlayer sandwiched between two metal layers. In alternative embodiments, the metal layers may include sublayers. A method is also provided for joining two ceramic articles using a single interlayer. An alternate bonding method provides a refractory-metal oxide interlayer placed adjacent to a strong oxide former. Aluminum or aluminum alloys are joined together using metal interlayers.

  5. A novel transient wall heat transfer approach for the start-up of SI engines with gasoline direct injection

    NASA Astrophysics Data System (ADS)

    Lejsek, David; Kulzer, André; Hammer, Jürgen

    2010-11-01

    The introduction of CO2-reduction technologies like Start-Stop or the Hybrid-Powertrain and the worldwide stringent emission legislation require a detailed optimization of the engine start-up. The combustion concept development as well as the calibration of the engine control unit makes an explicit thermodynamic analysis of the combustion process during the start-up necessary. Initially, the well-known thermodynamic analysis of in-cylinder pressure at stationary condition was transmitted to the highly non-stationary engine start-up. For this running mode of the engine the current models for calculation of the transient wall heat fluxes were found to be misleading. With a fraction of nearly 45% of the burned fuel energy, the wall heat is very important for the calculation of energy balance and for the combustion process analysis. Based on the measurements of transient wall heat transfer densities during the start-up presented in a former work (Lejsek and Kulzer in Investigations on the transient wall heat transfer at start-up for SI engines with gasoline direct injection. SAE Paper), the paper describes the development of adaptations to the known correlations by Woschni (MTZ 31:491, 1970), Hohenberg (Experimentelle Erfassung der Wandwärme von Kolbenmotoren. TU Graz, Habil., 1980) and Bargende (Ein Gleichungsansatz zur Berechnung der instationären Wandwärmeverluste im Hochdruckteil von Ottomotoren. TH Darmstadt, PhD-Thesis, 1991) for the application during engine start-up. To demonstrate the high accuracy of the model, the results of the cyclic resolved thermodynamic analysis using the presented novel approaches were compared with the results of the measurements. It is shown, that the novel heat flux models for the engine start-up process gives a cyclic resolved thermodynamic analysis to optimize the engine start-up pretty efficient.

  6. Apparatus Characterizes Transient Voltages in Real Time

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro

    2005-01-01

    The figure shows a prototype of a relatively inexpensive electronic monitoring apparatus that measures and records selected parameters of lightning-induced transient voltages on communication and power cables. The selected parameters, listed below, are those most relevant to the ability of lightning-induced transients to damage electronic equipment. This apparatus bridges a gap between some traditional transient-voltage recorders that record complete waveforms and other traditional transient-voltage recorders that record only peak values: By recording the most relevant parameters and only those parameters this apparatus yields more useful information than does a traditional peak-value (only) recorder while imposing much smaller data-storage and data-transmission burdens than does a traditional complete-waveform recorder. Also, relative to a complete-waveform recorder, this apparatus is more reliable and can be built at lower cost because it contains fewer electronic components. The transients generated by sources other than lightning tend to have frequency components well below 1 MHz. Most commercial transient recorders can detect and record such transients, but cannot respond rapidly enough for recording lightning-induced transient voltage peaks, which can rise from 10 to 90 percent of maximum amplitude in a fraction of a microsecond. Moreover, commercial transient recorders cannot rearm themselves rapidly enough to respond to the multiple transients that occur within milliseconds of each other on some lightning strikes. One transient recorder, designed for Kennedy Space Center earlier [ Fast Transient-Voltage Recorder (KSC- 11991), NASA Tech Briefs, Vol. 23, No. 10, page 6a (October 1999)], is capable of sampling transient voltages at peak values up to 50 V in four channels at a rate of 20 MHz. That recorder contains a trigger circuit that continuously compares the amplitudes of the signals on four channels to a preset triggering threshold. When a trigger signal

  7. Paediatric Virology as a new educational initiative: An interview with Nobelist Professor of Virology Harald zur Hausen.

    PubMed

    Mammas, Ioannis N; Spandidos, Demetrios A

    2017-10-01

    Born in Gelsenkirchen-Buer in Germany on March 11th, 1936, Professor Harald zur Hausen, Emeritus Professor of Virology at the University of Freiburg and 2008 Nobel Prize Laureate in Physiology or Medicine for his discovery of human papillomavirus (HPV), which causes cervical cancer, believes that good knowledge of virological methods and diagnostic possibilities are an asset for all young paediatricians. Professor zur Hausen considers that the creation of an educational platform on Paediatric Virology is definitely very beneficial for young paediatricians, as this will greatly enhance their knowledge in the field of Virology. He very actively advocates the vaccination of boys for the eradication of HPV infection and emphasises that male HPV vaccination should be included into the current vaccination programmes. He would have certainly considered Dr George N. Papanicolaou (Kyme, Island of Euboea, Greece, 1883 - Miami, Florida, USA, 1962) as an excellent candidate for the Nobel Prize, stating that the contribution of Dr Papanicolaou did not find sufficient recognition in the past. In the context of the 3rd Workshop on Paediatric Virology, which will be held in Athens, Greece, on October 7th, 2017, Professor zur Hausen will give his plenary lecture on 'Paediatric Virology and Oncology: Virus persistence and the important first years of life'.

  8. Paediatric Virology as a new educational initiative: An interview with Nobelist Professor of Virology Harald zur Hausen

    PubMed Central

    Mammas, Ioannis N.; Spandidos, Demetrios A.

    2017-01-01

    Born in Gelsenkirchen-Buer in Germany on March 11th, 1936, Professor Harald zur Hausen, Emeritus Professor of Virology at the University of Freiburg and 2008 Nobel Prize Laureate in Physiology or Medicine for his discovery of human papillomavirus (HPV), which causes cervical cancer, believes that good knowledge of virological methods and diagnostic possibilities are an asset for all young paediatricians. Professor zur Hausen considers that the creation of an educational platform on Paediatric Virology is definitely very beneficial for young paediatricians, as this will greatly enhance their knowledge in the field of Virology. He very actively advocates the vaccination of boys for the eradication of HPV infection and emphasises that male HPV vaccination should be included into the current vaccination programmes. He would have certainly considered Dr George N. Papanicolaou (Kyme, Island of Euboea, Greece, 1883 - Miami, Florida, USA, 1962) as an excellent candidate for the Nobel Prize, stating that the contribution of Dr Papanicolaou did not find sufficient recognition in the past. In the context of the 3rd Workshop on Paediatric Virology, which will be held in Athens, Greece, on October 7th, 2017, Professor zur Hausen will give his plenary lecture on ‘Paediatric Virology and Oncology: Virus persistence and the important first years of life’. PMID:29042913

  9. Cable coupling lightning transient qualification

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1989-01-01

    Simulated lightning strike testing of instrumentation cabling on the redesigned solid rocket motor was performed. Testing consisted of subjecting the lightning evaluation test article to simulated lightning strikes and evaluating the effects of instrumentation cable transients on cables within the system tunnel. The maximum short-circuit current induced onto a United Space Boosters, Inc., operational flight cable within the systems tunnel was 92 A, and the maximum induced open-circuit voltage was 316 V. These levels were extrapolated to the worst-case (200 kA) condition of NASA specification NSTS 07636 and were also scaled to full-scale redesigned solid rocket motor dimensions. Testing showed that voltage coupling to cables within the systems tunnel can be reduced 40 to 90 dB and that current coupling to cables within the systems tunnel can be reduced 30 to 70 dB with the use of braided metallic sock shields around cables that are external to the systems tunnel. Testing also showed that current and voltage levels induced onto cables within the systems tunnel are partially dependant on the cables' relative locations within the systems tunnel. Results of current injections to the systems tunnel indicate that the dominant coupling mode on cables within the systems tunnel is not from instrumentation cables but from coupling through the systems tunnel cover seam apertures. It is recommended that methods of improving the electrical bonding between individual sections of the systems tunnel covers be evaluated. Further testing to better characterize redesigned solid rocket motor cable coupling effects as an aid in developing methods to reduce coupling levels, particularly with respect to cable placement within the systems tunnel, is also recommended.

  10. Transient resonances in the inspirals

    NASA Astrophysics Data System (ADS)

    Hinderer, Tanja; Flanagan, Eanna

    2009-05-01

    We show that the two body problem in general relativity in the highly relativistic regime has a qualitatively new feature: the occurence of transient resonances. The resonances occur when the ratio of polar and radial orbital frequencies, which is slowly evolving under the influence of gravitational radiation reaction, passes through a low order rational number. The resonances make the orbit more sensitive to changes in the initial data (though not quite chaotic), and are genuine non-perturbative effects that are not seen at any order in the standard post-Newtonian expansion used for two body systems at large separation. Our results directly apply to an important potential source of gravitational waves, namely the gradual inspiral of compact objects into much more massive black holes. Exploiting observations of these gravitational waves to map the spacetime geometry of black holes is contingent upon accurate theoretical models (templates) of the binary dynamics. At present, only the leading order in the mass ratio gravitational waveforms can be computed. Corrections to the waveform's phase due to resonance effects scale as the square root of the inverse of the mass ratio and are characterized by sudden jumps in the time derivatives of the phase. We numerically estimate the net size of these corrections and find indications that the phase error is of order a few cycles for mass ratios ˜10^- 3 but will be significant (of order tens of cycles) for mass ratios ˜10-6. Computations of these corrections will require the computation of pieces of the forcing terms in the equations of motion which are currently unknown.

  11. Radio Transients and their Environments

    NASA Astrophysics Data System (ADS)

    Rajwade, Kaustubh

    The interstellar medium is the principal ingredient for star formation and hence, it is necessary to study the properties of the interstellar medium. Radio sources in our Galaxy and beyond can be used as a probe of the intervening medium. In this dissertation, I present an attempt to use radio transients like pulsars and fast radio bursts and their interactions with the environment around them to study interstellar medium. We show that radio emission from pulsars is absorbed by dense ionized gas in their surroundings, causing a turnover in their flux density spectrum that can be used to reveal information about the absorbing medium. We carried out a multi-wavelength observation campaign of PSR B0611+22. The pulsar shows peculiar emission variability that is broadband in nature. Moreover, we show that the flux density spectrum of B0611+22 is unusual which can be attributed to the environment it lies in. We also present predictions of fast radio burst detections from upcoming low frequency surveys. We show that future surveys with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) will be able to detect 1 radio burst per hour even if the radio burst undergoes significant absorption and scattering. Finally, we present our results of pulsar population synthesis to understand the pulsar population in the Galactic Centre (GC) and place conservative upper limits on the GC pulsar population. We obtain an upper limit of 52 CPs and 10,000 MSPs in the GC. The dense, ionized environment of the GC gives us the opportunity to predict the probability of detection by considering scattering and absorption as the principle sources of flux mitigation. Our results suggest that the optimal frequency range for a pulsar survey in the GC is 9-14 GHz. A larger sample of absorbed spectrum pulsars and fast radio bursts will be beneficial not only for the study of emission processes but also for discerning the properties of the material permeating through space.

  12. Characterizing SI Engine Transient Fuel Consumption in ALPHA

    EPA Science Inventory

    Examine typical transient engine operation encountered over the EPA's vehicle and engine testing drive cycles to characterize that transient fuel usage, and then describe the changes made to ALPHA to better model transient engine operation.

  13. Transient statistics in stabilizing periodic orbits

    NASA Astrophysics Data System (ADS)

    Meucci, R.; Gadomski, W.; Ciofini, M.; Arecchi, F. T.

    1995-11-01

    The statistics of chaotic and periodic transient time intervals preceding the stabilization of a given periodic orbit have been experimentally studied in a CO2 laser with modulated losses, subjected to a small subharmonic perturbation. As predicted by the theory, an exponential tail has been found in the probability distribution of chaotic transients. Furthermore, a fine periodic structure in the distributions of the periodic transients, resulting from the interaction of the control signal and the local structure of the chaotic attractor, has been revealed.

  14. Conducted Transients on Spacecraft Primary Power Lines

    NASA Technical Reports Server (NTRS)

    Mc Closkey, John; Dimov, Jen

    2017-01-01

    One of the sources of potential interference on spacecraft primary power lines is that of conducted transients resulting from equipment being switched on and off of the bus. Susceptibility to such transients is addressed by some version of the CS06 requirement of MIL-STD-461462. This presentation provides a summary of the history of the CS06 requirement and test method, a basis for understanding of the sources of these transients, analysis techniques for determining their worst-case characteristics, and guidelines for minimizing their magnitudes and applying the requirement appropriately.

  15. Single-Event Transients in Voltage Regulators

    NASA Technical Reports Server (NTRS)

    Johnston, Allan H.; Miyahira, Tetsuo F.; Irom, F.; Laird, Jamie S.

    2006-01-01

    Single-event transients are investigated for two voltage regulator circuits that are widely used in space. A circuit-level model is developed that can be used to determine how transients are affected by different circuit application conditions. Internal protection circuits-which are affected by load as well as internal thermal effects-can also be triggered from heavy ions, causing dropouts or shutdown ranging from milliseconds to seconds. Although conventional output transients can be reduced by adding load capacitance, that approach is ineffective for dropouts from protection circuitry.

  16. Transient studies of capillary-induced flow

    NASA Technical Reports Server (NTRS)

    Reagan, M. K.; Bowman, W. J.

    1993-01-01

    This paper presents the numerical and experimental results of a study performed on the transient rise of fluid in a capillary tube. The capillary tube problem provides an excellent mechanism from which to launch an investigation into the transient flow of a fluid in a porous wick structure where capillary forces must balance both adverse gravitational effects and frictional losses. For the study, a capillary tube, initially charged with a small volume of water, was lowered into a pool of water. The behavior of the column of fluid during the transient that followed as more water entered the tube from the pool was both numerically and experimentally studied.

  17. Vergleich von rekombinanten Vaccinia- und DNA-Vektoren zur Tumorimmuntherapie im C57BL/6-Mausmodell

    NASA Astrophysics Data System (ADS)

    Johnen, Heiko

    2002-10-01

    In der vorliegenden Arbeit wurden Tumorimpfstoffe auf der Basis des Plasmid-Vektors pCI, modified vaccinia virus Ankara (MVA) und MVA-infizierten dendritischen Zellen entwickelt und durch Sequenzierung, Western blotting und durchflußzytometrische Analyse überprüft. Die in vivo Wirksamkeit der Vakzinen wurde in verschiedenen Tumormodellen in C57BL/6 Mäusen verglichen. Die auf dem eukaryotischen Expressionsvektor pCI basierende DNA-Vakzinierung induzierte einen sehr wirksamen, antigenspezifischen und langfristigen Schutz vor Muzin, CEA oder beta-Galactosidase exprimierenden Tumoren. Eine MVA-Vakzinierung bietet in den in dieser Arbeit durchgeführten Tumormodellen keinen signifikanten Schutz vor Muzin oder beta-Galactosidase exprimierenden Tumoren. Sowohl humane, als auch murine in vitro generierte dendritische Zellen lassen sich mit MVA – im Vergleich zu anderen viralen Vektoren – sehr gut infizieren. Die Expressionsrate der eingefügten Gene ist aber gering im Vergleich zur Expression in permissiven Wirtszellen des Virus (embryonale Hühnerfibroblasten). Es konnte gezeigt werden, daß eine MVA-Infektion dendritischer Zellen ähnliche Auswirkungen auf den Reifezustand humaner und muriner dendritischer Zellen hat, wie eine Infektion mit replikationskompetenten Vakzinia-Stämmen, und außerdem die Hochregulation von CD40 während der terminalen Reifung von murinen dendritischen Zellen inhibiert wird. Die während der langfristigen in vitro Kultur auf CEF-Zellen entstandenen Deletionen im MVA Genom führten zu einer starken Attenuierung und dem Verlust einiger Gene, die immunmodulatorische Proteine kodieren, jedoch nicht zu einer Verminderung des zytopathischen Effekts in dendritischen Zellen. Die geringe Expressionsrate und die beobachtete Inhibition der Expression kostimulatorischer Moleküle auf dendritischen Zellen kann für eine wenig effektive Induktion einer Immunantwort in MVA vakzinierten Tieren durch cross priming oder die direkte Infektion

  18. Transient loads analysis for space flight applications

    NASA Technical Reports Server (NTRS)

    Thampi, S. K.; Vidyasagar, N. S.; Ganesan, N.

    1992-01-01

    A significant part of the flight readiness verification process involves transient analysis of the coupled Shuttle-payload system to determine the low frequency transient loads. This paper describes a methodology for transient loads analysis and its implementation for the Spacelab Life Sciences Mission. The analysis is carried out using two major software tools - NASTRAN and an external FORTRAN code called EZTRAN. This approach is adopted to overcome some of the limitations of NASTRAN's standard transient analysis capabilities. The method uses Data Recovery Matrices (DRM) to improve computational efficiency. The mode acceleration method is fully implemented in the DRM formulation to recover accurate displacements, stresses, and forces. The advantages of the method are demonstrated through a numerical example.

  19. On transient rheology and glacial isostasy

    NASA Technical Reports Server (NTRS)

    Yuen, David A.; Sabadini, Roberto C. A.; Gasperini, Paolo; Boschi, Enzo

    1986-01-01

    The effect of transient creep on the inference of long-term mantle viscosity is investigated using theoretical predictions from self-gravitating, layered earth models with Maxwell, Burgers' body, and standard linear solid rheologies. The interaction between transient and steady-state rheologies is studied. The responses of the standard linear solid and Burgers' body models to transient creep in the entire mantle, and of the Burgers' body and Maxwell models to creep in the lower mantle are described. The models' responses are examined in terms of the surface displacement, free air gravity anomaly, wander of the rotation pole, and the secular variation of the degree 2 zonal coefficient of the earth's gravitational potential field. The data reveal that transient creep cannot operate throughout the entire mantle.

  20. Transients control in Raman fiber amplifiers

    NASA Astrophysics Data System (ADS)

    Freitas, Marcio; Givigi, Sidney N., Jr.; Klein, Jackson; Calmon, Luiz C.; de Almeida, Ailson R.

    2004-11-01

    Raman fiber amplifiers (RFA) are being used in optical transmission communication systems in the recent years due to their advantages in comparison to erbium-doped fiber amplifiers (EDFA). Recently the analysis of RFAs dynamic response and transients control has become important in order to predict the system response to add/drop of channels or cable cuts in optical systems, and avoid impairments caused by the power transients. Fast signal power transients in the surviving channels are caused by the cross-gain saturation effect in RFA and the slope of the gain saturation characteristics determines the steady-state surviving channel power excursion. We are presenting the modeling and analysis of power transients and its control using a pump control method for a single and multi-pump scheme.

  1. Transient Tachypnea of the Newborn (TTN)

    MedlinePlus

    ... newborn receives IV fluids. Sometimes babies can take breast milk or formula through a nasogastric (NG) or orogastric ( ... of these tubes, ask the doctor about providing breast milk for your baby. Symptoms of transient tachypnea usually ...

  2. Transient Phenomena: Opportunities for New Discoveries

    NASA Technical Reports Server (NTRS)

    Lazio, T. Joseph W.

    2010-01-01

    Known classes of radio wavelength transients range from the nearby (stellar flares and radio pulsars) to the distant Universe (gamma-ray burst afterglows). Hypothesized classes of radio transients include analogs of known objects, such as extrasolar planets emitting Jovian-like radio bursts and giant-pulse emitting pulsars in other galaxies, to the exotic, such as prompt emission from gamma-ray bursts, evaporating black holes and transmitters from other civilizations. Time domain astronomy has been recognized internationally as a means of addressing key scientific questions in astronomy and physics, and pathfinders and Precursors to the Square Kilometre Array (SKA) are beginning to offer a combination of wider fields of view and more wavelength agility than has been possible in the past. These improvements will continue when the SKA itself becomes operational. I illustrate the range of transient phenomena and discuss how the detection and study of radio transients will improve immensely.

  3. Hybrid Hydrostatic/Transient Roller Bearing Assembly

    NASA Technical Reports Server (NTRS)

    Justak, John F.

    1992-01-01

    Proposed bearing assembly for shaft of high-speed turbopump includes both hydrostatic and rolling-element bearings. Rolling-element bearing unloaded at high speed by centrifugal expansion of outer race and transient retainer.

  4. Transient thermal analysis of fluid systems

    NASA Technical Reports Server (NTRS)

    Chandler, G. D.; Trust, R. D.

    1977-01-01

    Computer program performs transient thermal analysis of any 2-node to 200-node-thermal network, which transports heat by fluid flow convection. Program can be modified to add conduction along tubes and radiation.

  5. Willkommen, Mr. Chance: Methodologische Betrachtungen zur Gute empirischer Forschung in der Padagogik, diskutiert vor allem an der neueren Untersuchung uber Gewalt von Heitmeyer u.a. (1995) = Welcome, Mr. Chance: Methodological Considerations Concerning the Quality of Empirical Research in Educational Science Based on a Recent Study on Violence Published by Heitmeyer et al. (1995).

    ERIC Educational Resources Information Center

    Wellenreuther, Martin

    1997-01-01

    Argues that the usefulness of strictly quantitative research is still questioned in educational studies, primarily due to deficiencies in methodological training. Uses a critique of a recent study by Heitmeyer et al. (1995) to illustrate the requirements of "good" empirical research. Considers the problems of hypothesis testing in field research.…

  6. Transient diabetes insipidus in pregnancy

    PubMed Central

    Gunawardana, Kavinga; Grossman, Ashley

    2015-01-01

    Summary Gestational diabetes insipidus (DI) is a rare complication of pregnancy, usually developing in the third trimester and remitting spontaneously 4–6 weeks post-partum. It is mainly caused by excessive vasopressinase activity, an enzyme expressed by placental trophoblasts which metabolises arginine vasopressin (AVP). Its diagnosis is challenging, and the treatment requires desmopressin. A 38-year-old Chinese woman was referred in the 37th week of her first single-gestation due to polyuria, nocturia and polydipsia. She was known to have gestational diabetes mellitus diagnosed in the second trimester, well-controlled with diet. Her medical history was unremarkable. Physical examination demonstrated decreased skin turgor; her blood pressure was 102/63 mmHg, heart rate 78 beats/min and weight 53 kg (BMI 22.6 kg/m2). Laboratory data revealed low urine osmolality 89 mOsmol/kg (350–1000), serum osmolality 293 mOsmol/kg (278–295), serum sodium 144 mmol/l (135–145), potassium 4.1 mmol/l (3.5–5.0), urea 2.2 mmol/l (2.5–6.7), glucose 3.5 mmol/l and HbA1c 5.3%. Bilirubin, alanine transaminase, alkaline phosphatase and full blood count were normal. The patient was started on desmopressin with improvement in her symptoms, and normalisation of serum and urine osmolality (280 and 310 mOsmol/kg respectively). A fetus was delivered at the 39th week without major problems. After delivery, desmopressin was stopped and she had no further evidence of polyuria, polydipsia or nocturia. Her sodium, serum/urine osmolality at 12-weeks post-partum were normal. A pituitary magnetic resonance imaging (MRI) revealed the neurohypophyseal T1-bright spot situated ectopically, with a normal adenohypophysis and infundibulum. She remains clinically well, currently breastfeeding, and off all medication. This case illustrates some challenges in the diagnosis and management of transient gestational DI. Learning points Gestational DI is a rare complication of

  7. Transient diabetes insipidus in pregnancy.

    PubMed

    Marques, Pedro; Gunawardana, Kavinga; Grossman, Ashley

    2015-01-01

    Gestational diabetes insipidus (DI) is a rare complication of pregnancy, usually developing in the third trimester and remitting spontaneously 4-6 weeks post-partum. It is mainly caused by excessive vasopressinase activity, an enzyme expressed by placental trophoblasts which metabolises arginine vasopressin (AVP). Its diagnosis is challenging, and the treatment requires desmopressin. A 38-year-old Chinese woman was referred in the 37th week of her first single-gestation due to polyuria, nocturia and polydipsia. She was known to have gestational diabetes mellitus diagnosed in the second trimester, well-controlled with diet. Her medical history was unremarkable. Physical examination demonstrated decreased skin turgor; her blood pressure was 102/63 mmHg, heart rate 78 beats/min and weight 53 kg (BMI 22.6 kg/m(2)). Laboratory data revealed low urine osmolality 89 mOsmol/kg (350-1000), serum osmolality 293 mOsmol/kg (278-295), serum sodium 144 mmol/l (135-145), potassium 4.1 mmol/l (3.5-5.0), urea 2.2 mmol/l (2.5-6.7), glucose 3.5 mmol/l and HbA1c 5.3%. Bilirubin, alanine transaminase, alkaline phosphatase and full blood count were normal. The patient was started on desmopressin with improvement in her symptoms, and normalisation of serum and urine osmolality (280 and 310 mOsmol/kg respectively). A fetus was delivered at the 39th week without major problems. After delivery, desmopressin was stopped and she had no further evidence of polyuria, polydipsia or nocturia. Her sodium, serum/urine osmolality at 12-weeks post-partum were normal. A pituitary magnetic resonance imaging (MRI) revealed the neurohypophyseal T1-bright spot situated ectopically, with a normal adenohypophysis and infundibulum. She remains clinically well, currently breastfeeding, and off all medication. This case illustrates some challenges in the diagnosis and management of transient gestational DI. Gestational DI is a rare complication of pregnancy occurring in two to four out of

  8. Four RNA families with functional transient structures

    PubMed Central

    Zhu, Jing Yun A; Meyer, Irmtraud M

    2015-01-01

    Protein-coding and non-coding RNA transcripts perform a wide variety of cellular functions in diverse organisms. Several of their functional roles are expressed and modulated via RNA structure. A given transcript, however, can have more than a single functional RNA structure throughout its life, a fact which has been previously overlooked. Transient RNA structures, for example, are only present during specific time intervals and cellular conditions. We here introduce four RNA families with transient RNA structures that play distinct and diverse functional roles. Moreover, we show that these transient RNA structures are structurally well-defined and evolutionarily conserved. Since Rfam annotates one structure for each family, there is either no annotation for these transient structures or no such family. Thus, our alignments either significantly update and extend the existing Rfam families or introduce a new RNA family to Rfam. For each of the four RNA families, we compile a multiple-sequence alignment based on experimentally verified transient and dominant (dominant in terms of either the thermodynamic stability and/or attention received so far) RNA secondary structures using a combination of automated search via covariance model and manual curation. The first alignment is the Trp operon leader which regulates the operon transcription in response to tryptophan abundance through alternative structures. The second alignment is the HDV ribozyme which we extend to the 5′ flanking sequence. This flanking sequence is involved in the regulation of the transcript's self-cleavage activity. The third alignment is the 5′ UTR of the maturation protein from Levivirus which contains a transient structure that temporarily postpones the formation of the final inhibitory structure to allow translation of maturation protein. The fourth and last alignment is the SAM riboswitch which regulates the downstream gene expression by assuming alternative structures upon binding of SAM

  9. Four RNA families with functional transient structures.

    PubMed

    Zhu, Jing Yun A; Meyer, Irmtraud M

    2015-01-01

    Protein-coding and non-coding RNA transcripts perform a wide variety of cellular functions in diverse organisms. Several of their functional roles are expressed and modulated via RNA structure. A given transcript, however, can have more than a single functional RNA structure throughout its life, a fact which has been previously overlooked. Transient RNA structures, for example, are only present during specific time intervals and cellular conditions. We here introduce four RNA families with transient RNA structures that play distinct and diverse functional roles. Moreover, we show that these transient RNA structures are structurally well-defined and evolutionarily conserved. Since Rfam annotates one structure for each family, there is either no annotation for these transient structures or no such family. Thus, our alignments either significantly update and extend the existing Rfam families or introduce a new RNA family to Rfam. For each of the four RNA families, we compile a multiple-sequence alignment based on experimentally verified transient and dominant (dominant in terms of either the thermodynamic stability and/or attention received so far) RNA secondary structures using a combination of automated search via covariance model and manual curation. The first alignment is the Trp operon leader which regulates the operon transcription in response to tryptophan abundance through alternative structures. The second alignment is the HDV ribozyme which we extend to the 5' flanking sequence. This flanking sequence is involved in the regulation of the transcript's self-cleavage activity. The third alignment is the 5' UTR of the maturation protein from Levivirus which contains a transient structure that temporarily postpones the formation of the final inhibitory structure to allow translation of maturation protein. The fourth and last alignment is the SAM riboswitch which regulates the downstream gene expression by assuming alternative structures upon binding of SAM. All

  10. Transient Cognitive Dynamics, Metastability, and Decision Making

    PubMed Central

    Rabinovich, Mikhail I.; Huerta, Ramón; Varona, Pablo; Afraimovich, Valentin S.

    2008-01-01

    The idea that cognitive activity can be understood using nonlinear dynamics has been intensively discussed at length for the last 15 years. One of the popular points of view is that metastable states play a key role in the execution of cognitive functions. Experimental and modeling studies suggest that most of these functions are the result of transient activity of large-scale brain networks in the presence of noise. Such transients may consist of a sequential switching between different metastable cognitive states. The main problem faced when using dynamical theory to describe transient cognitive processes is the fundamental contradiction between reproducibility and flexibility of transient behavior. In this paper, we propose a theoretical description of transient cognitive dynamics based on the interaction of functionally dependent metastable cognitive states. The mathematical image of such transient activity is a stable heteroclinic channel, i.e., a set of trajectories in the vicinity of a heteroclinic skeleton that consists of saddles and unstable separatrices that connect their surroundings. We suggest a basic mathematical model, a strongly dissipative dynamical system, and formulate the conditions for the robustness and reproducibility of cognitive transients that satisfy the competing requirements for stability and flexibility. Based on this approach, we describe here an effective solution for the problem of sequential decision making, represented as a fixed time game: a player takes sequential actions in a changing noisy environment so as to maximize a cumulative reward. As we predict and verify in computer simulations, noise plays an important role in optimizing the gain. PMID:18452000

  11. Advanced Instrumentation for Transient Reactor Testing

    SciT

    Corradini, Michael L.; Anderson, Mark; Imel, George

    Transient testing involves placing fuel or material into the core of specialized materials test reactors that are capable of simulating a range of design basis accidents, including reactivity insertion accidents, that require the reactor produce short bursts of intense highpower neutron flux and gamma radiation. Testing fuel behavior in a prototypic neutron environment under high-power, accident-simulation conditions is a key step in licensing nuclear fuels for use in existing and future nuclear power plants. Transient testing of nuclear fuels is needed to develop and prove the safety basis for advanced reactors and fuels. In addition, modern fuel development and designmore » increasingly relies on modeling and simulation efforts that must be informed and validated using specially designed material performance separate effects studies. These studies will require experimental facilities that are able to support variable scale, highly instrumented tests providing data that have appropriate spatial and temporal resolution. Finally, there are efforts now underway to develop advanced light water reactor (LWR) fuels with enhanced performance and accident tolerance. These advanced reactor designs will also require new fuel types. These new fuels need to be tested in a controlled environment in order to learn how they respond to accident conditions. For these applications, transient reactor testing is needed to help design fuels with improved performance. In order to maximize the value of transient testing, there is a need for in-situ transient realtime imaging technology (e.g., the neutron detection and imaging system like the hodoscope) to see fuel motion during rapid transient excursions with a higher degree of spatial and temporal resolution and accuracy. There also exists a need for new small, compact local sensors and instrumentation that are capable of collecting data during transients (e.g., local displacements, temperatures, thermal conductivity, neutron flux

  12. Features of postfailure fuel behavior in transient overpower and transient undercooled/overpower tests in the transient reactor test facility

    SciT

    Doerner, R.C.; Bauer, T.H.; Morman, J.A.

    Prototypic oxide fuel was subjected to simulated, fast reactor severe accident conditions in a series of in-pile tests in the Transient Reactor Test Facility reactor. Seven experiments were performed on fresh and previously irradiated oxide fuel pins under transient overpower and transient undercooled. overpower accident conditions. For each of the tests, fuel motions were observed by the hodoscope. Hodoscope data are correlated with coolant flow, pressure, and temperature data recorded by the loop instrumentation. Data were analyzed from the onset of initial failure to a final mass distribution at the end of the test. In this paper results of thesemore » analyses are compared to pre- and posttest accident calculations and to posttest metallographic accident calculations and to posttest metallographic examinations and computed tomographic reconstructions from neutron radiographs.« less

  13. Transient triggering of near and distant earthquakes

    Gomberg, J.; Blanpied, M.L.; Beeler, N.M.

    1997-01-01

    We demonstrate qualitatively that frictional instability theory provides a context for understanding how earthquakes may be triggered by transient loads associated with seismic waves from near and distance earthquakes. We assume that earthquake triggering is a stick-slip process and test two hypotheses about the effect of transients on the timing of instabilities using a simple spring-slider model and a rate- and state-dependent friction constitutive law. A critical triggering threshold is implicit in such a model formulation. Our first hypothesis is that transient loads lead to clock advances; i.e., transients hasten the time of earthquakes that would have happened eventually due to constant background loading alone. Modeling results demonstrate that transient loads do lead to clock advances and that the triggered instabilities may occur after the transient has ceased (i.e., triggering may be delayed). These simple "clock-advance" models predict complex relationships between the triggering delay, the clock advance, and the transient characteristics. The triggering delay and the degree of clock advance both depend nonlinearly on when in the earthquake cycle the transient load is applied. This implies that the stress required to bring about failure does not depend linearly on loading time, even when the fault is loaded at a constant rate. The timing of instability also depends nonlinearly on the transient loading rate, faster rates more rapidly hastening instability. This implies that higher-frequency and/or longer-duration seismic waves should increase the amount of clock advance. These modeling results and simple calculations suggest that near (tens of kilometers) small/moderate earthquakes and remote (thousands of kilometers) earthquakes with magnitudes 2 to 3 units larger may be equally effective at triggering seismicity. Our second hypothesis is that some triggered seismicity represents earthquakes that would not have happened without the transient load (i

  14. Synchronizing noisy nonidentical oscillators by transient uncoupling

    SciT

    Tandon, Aditya, E-mail: adityat@iitk.ac.in; Mannattil, Manu, E-mail: mmanu@iitk.ac.in; Schröder, Malte, E-mail: malte@nld.ds.mpg.de

    2016-09-15

    Synchronization is the process of achieving identical dynamics among coupled identical units. If the units are different from each other, their dynamics cannot become identical; yet, after transients, there may emerge a functional relationship between them—a phenomenon termed “generalized synchronization.” Here, we show that the concept of transient uncoupling, recently introduced for synchronizing identical units, also supports generalized synchronization among nonidentical chaotic units. Generalized synchronization can be achieved by transient uncoupling even when it is impossible by regular coupling. We furthermore demonstrate that transient uncoupling stabilizes synchronization in the presence of common noise. Transient uncoupling works best if the unitsmore » stay uncoupled whenever the driven orbit visits regions that are locally diverging in its phase space. Thus, to select a favorable uncoupling region, we propose an intuitive method that measures the local divergence at the phase points of the driven unit's trajectory by linearizing the flow and subsequently suppresses the divergence by uncoupling.« less

  15. SPIRITS: Uncovering Unusual Infrared Transients with Spitzer

    NASA Astrophysics Data System (ADS)

    Kasliwal, Mansi M.; Bally, John; Masci, Frank; Cody, Ann Marie; Bond, Howard E.; Jencson, Jacob E.; Tinyanont, Samaporn; Cao, Yi; Contreras, Carlos; Dykhoff, Devin A.; Amodeo, Samuel; Armus, Lee; Boyer, Martha; Cantiello, Matteo; Carlon, Robert L.; Cass, Alexander C.; Cook, David; Corgan, David T.; Faella, Joseph; Fox, Ori D.; Green, Wayne; Gehrz, R. D.; Helou, George; Hsiao, Eric; Johansson, Joel; Khan, Rubab M.; Lau, Ryan M.; Langer, Norbert; Levesque, Emily; Milne, Peter; Mohamed, Shazrene; Morrell, Nidia; Monson, Andy; Moore, Anna; Ofek, Eran O.; O' Sullivan, Donal; Parthasarathy, Mudumba; Perez, Andres; Perley, Daniel A.; Phillips, Mark; Prince, Thomas A.; Shenoy, Dinesh; Smith, Nathan; Surace, Jason; Van Dyk, Schuyler D.; Whitelock, Patricia A.; Williams, Robert

    2017-04-01

    We present an ongoing, five-year systematic search for extragalactic infrared transients, dubbed SPIRITS—SPitzer InfraRed Intensive Transients Survey. In the first year, using Spitzer/IRAC, we searched 190 nearby galaxies with cadence baselines of one month and six months. We discovered over 1958 variables and 43 transients. Here, we describe the survey design and highlight 14 unusual infrared transients with no optical counterparts to deep limits, which we refer to as SPRITEs (eSPecially Red Intermediate-luminosity Transient Events). SPRITEs are in the infrared luminosity gap between novae and supernovae, with [4.5] absolute magnitudes between -11 and -14 (Vega-mag) and [3.6]-[4.5] colors between 0.3 mag and 1.6 mag. The photometric evolution of SPRITEs is diverse, ranging from <0.1 mag yr-1 to >7 mag yr-1. SPRITEs occur in star-forming galaxies. We present an in-depth study of one of them, SPIRITS 14ajc in Messier 83, which shows shock-excited molecular hydrogen emission. This shock may have been triggered by the dynamic decay of a non-hierarchical system of massive stars that led to either the formation of a binary or a protostellar merger.

  16. Transient particle emission measurement with optical techniques

    NASA Astrophysics Data System (ADS)

    Bermúdez, Vicente; Luján, José M.; Serrano, José R.; Pla, Benjamín

    2008-06-01

    Particulate matter is responsible for some respiratory and cardiovascular diseases. In addition, it is one of the most important pollutants of high-speed direct injection (HSDI) passenger car engines. Current legislation requires particulate dilution tunnels for particulate matter measuring. However for development work, dilution tunnels are expensive and sometimes not useful since they are not able to quantify real-time particulate emissions during transient operation. In this study, the use of a continuous measurement opacimeter and a fast response HFID is proven to be a good alternative to obtain instantaneous particle mass emissions during transient operation (due to particulate matter consisting mainly of soot and SOF). Some methods and correlations available from literature, but developed for steady conditions, are evaluated during transient operation by comparing with mini-tunnel measurements during the entire MVEG-A transient cycle. A new correlation was also derived from this evaluation. Results for soot and SOF (obtained from the new correlation proposed) are compared with soot and SOF captured with particulate filters, which have been separated by means of an SOF extraction method. Finally, as an example of ECU design strategies using these sort of correlations, the EGR valve opening is optimized during transient operation. The optimization is performed while simultaneously taking into account instantaneous fuel consumption, particulate emissions (calculated with the proposed correlation) and other regulated engine pollutants.

  17. Transient simulation of molten salt central receiver

    NASA Astrophysics Data System (ADS)

    Doupis, Dimitri; Wang, Chuan; Carcorze-Soto, Jorge; Chen, Yen-Ming; Maggi, Andrea; Losito, Matteo; Clark, Michael

    2016-05-01

    Alstom is developing concentrated solar power (CSP) utilizing 60/40wt% NaNO3-KNO3 molten salt as the working fluid in a tower receiver for the global renewable energy market. In the CSP power generation cycle, receivers undergo a daily cyclic operation due to the transient nature of solar energy. Development of robust and efficient start-up and shut-down procedures is critical to avoiding component failures due to mechanical fatigue resulting from thermal transients, thus maintaining the performance and availability of the CSP plant. The Molten Salt Central Receiver (MSCR) is subject to thermal transients during normal daily operation, a cycle that includes warmup, filling, operation, draining, and shutdown. This paper describes a study to leverage dynamic simulation and finite element analysis (FEA) in development of start-up, shutdown, and transient operation concepts for the MSCR. The results of the FEA also verify the robustness of the MSCR design to the thermal transients anticipated during the operation of the plant.

  18. SPIRITS: Uncovering Unusual Infrared Transients with Spitzer

    SciT

    Kasliwal, Mansi M.; Jencson, Jacob E.; Tinyanont, Samaporn

    2017-04-20

    We present an ongoing, five-year systematic search for extragalactic infrared transients, dubbed SPIRITS—SPitzer InfraRed Intensive Transients Survey. In the first year, using Spitzer /IRAC, we searched 190 nearby galaxies with cadence baselines of one month and six months. We discovered over 1958 variables and 43 transients. Here, we describe the survey design and highlight 14 unusual infrared transients with no optical counterparts to deep limits, which we refer to as SPRITEs (eSPecially Red Intermediate-luminosity Transient Events). SPRITEs are in the infrared luminosity gap between novae and supernovae, with [4.5] absolute magnitudes between −11 and −14 (Vega-mag) and [3.6]–[4.5] colors betweenmore » 0.3 mag and 1.6 mag. The photometric evolution of SPRITEs is diverse, ranging from <0.1 mag yr{sup −1} to >7 mag yr{sup −1}. SPRITEs occur in star-forming galaxies. We present an in-depth study of one of them, SPIRITS 14ajc in Messier 83, which shows shock-excited molecular hydrogen emission. This shock may have been triggered by the dynamic decay of a non-hierarchical system of massive stars that led to either the formation of a binary or a protostellar merger.« less

  19. Moisture-triggered physically transient electronics

    PubMed Central

    Gao, Yang; Zhang, Ying; Wang, Xu; Sim, Kyoseung; Liu, Jingshen; Chen, Ji; Feng, Xue; Xu, Hangxun; Yu, Cunjiang

    2017-01-01

    Physically transient electronics, a form of electronics that can physically disappear in a controllable manner, is very promising for emerging applications. Most of the transient processes reported so far only occur in aqueous solutions or biofluids, offering limited control over the triggering and degradation processes. We report novel moisture-triggered physically transient electronics, which exempt the needs of resorption solutions and can completely disappear within well-controlled time frames. The triggered transient process starts with the hydrolysis of the polyanhydride substrate in the presence of trace amounts of moisture in the air, a process that can generate products of corrosive organic acids to digest various inorganic electronic materials and components. Polyanhydride is the only example of polymer that undergoes surface erosion, a distinct feature that enables stable operation of the functional devices over a predefined time frame. Clear advantages of this novel triggered transience mode include that the lifetime of the devices can be precisely controlled by varying the moisture levels and changing the composition of the polymer substrate. The transience time scale can be tuned from days to weeks. Various transient devices, ranging from passive electronics (such as antenna, resistor, and capacitor) to active electronics (such as transistor, diodes, optoelectronics, and memories), and an integrated system as a platform demonstration have been developed to illustrate the concept and verify the feasibility of this design strategy. PMID:28879237

  20. Ganzheitliche Digitalisierungsansätze im Stadtwerk: Von der Strategie bis zur Umsetzung

    NASA Astrophysics Data System (ADS)

    Dudenhausen, Roman; Hahn, Heike

    Digitalisierung muss im Stadtwerk dazu führen, Kundenerwartungen, die heutzutage schon vielfach durch digitales Know-how und Erfahrungen geprägt sind, in einzigartiger Weise zu entsprechen - in Form digitaler Kundenkontaktpunkte, automatisierter Prozesse oder plattformbasierter Geschäftsmodelle. Eine große Rolle spielen dabei unternehmensweit nutzbare Informationen, die eine 360-Grad-Sicht auf den Kunden ermöglichen. Nur in dieser Kombination werden sich nachhaltig Wettbewerbsvorteile generieren lassen. Manch ein Kunde wird die Lust, einen Prozess zu Ende zu gehen, schon vor dem Abschluss verlieren, wenn er nicht unmittelbar und ohne die digitale Welt zu verlassen zum Ziel kommt. Eine nur "halb digitale Kundenerfahrung" wird weder zu Neugeschäft noch zur positiven emotionalen Bindung zwischen Kunden und Stadtwerk führen. Nicht zu unterschätzen sind zudem Erwartungen hinsichtlich zukünftiger Geschäftsmodelle, aus denen sich disruptive Bedrohungen für die herkömmlichen Strom- und Gasangebote ergeben werden. Erste innovative Ansätze finden sich bereits im Markt, die erahnen lassen, dass zurzeit viel diskutierte Technologien wie die Blockchain nicht mehr nur hypothetischer Natur sind. Die Auseinandersetzung mit der Digitalisierung erfolgt dabei sinnvollerweise in einem unternehmensweit abgestimmten Rahmen, der eine zielgerichtete und ganzheitliche Vorgehensweise ermöglicht.

  1. [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. © 2016 S. Karger GmbH, Freiburg.

  2. Apparent dispersion in transient groundwater flow

    Goode, Daniel J.; Konikow, Leonard F.

    1990-01-01

    This paper investigates the effects of large-scale temporal velocity fluctuations, particularly changes in the direction of flow, on solute spreading in a two-dimensional aquifer. Relations for apparent longitudinal and transverse dispersivity are developed through an analytical solution for dispersion in a fluctuating, quasi-steady uniform flow field, in which storativity is zero. For transient flow, spatial moments are evaluated from numerical solutions. Ignored or unknown transients in the direction of flow primarily act to increase the apparent transverse dispersivity because the longitudinal dispersivity is acting in a direction that is not the assumed flow direction. This increase is a function of the angle between the transient flow vector and the assumed steady state flow direction and the ratio of transverse to longitudinal dispersivity. The maximum effect on transverse dispersivity occurs if storativity is assumed to be zero, such that the flow field responds instantly to boundary condition changes.

  3. Transient response in granular bounded heap flows

    NASA Astrophysics Data System (ADS)

    Xiao, Hongyi; Ottino, Julio M.; Lueptow, Richard M.; Umbanhowar, Paul B.

    2017-11-01

    Heap formation, a canonical granular flow, is common in industry and is also found in nature. Here, we study the transition between steady flow states in quasi-2D bounded heaps by suddenly changing the feed rate from one fixed value to another. During the transition, in both experiments and discrete element method simulations, an additional wedge of flowing particles propagates over the rising free surface. The downstream edge of the wedge - the wedge front - moves downstream with velocity inversely proportional to the square root of time. An additional longer duration transient process continues after the wedge front reaches the downstream wall. The transient flux profile during the entire transition is well modeled by a diffusion-like equation derived from local mass balance and a local linear relation between the flux and the surface slope. Scalings for the transient kinematics during the flow transitions are developed based on the flux profiles. Funded by NSF Grant CBET-1511450.

  4. Modeling of environmentally induced transients within satellites

    NASA Technical Reports Server (NTRS)

    Stevens, N. John; Barbay, Gordon J.; Jones, Michael R.; Viswanathan, R.

    1987-01-01

    A technique is described that allows an estimation of possible spacecraft charging hazards. This technique, called SCREENS (spacecraft response to environments of space), utilizes the NASA charging analyzer program (NASCAP) to estimate the electrical stress locations and the charge stored in the dielectric coatings due to spacecraft encounter with a geomagnetic substorm environment. This information can then be used to determine the response of the spacecraft electrical system to a surface discharge by means of lumped element models. The coupling into the electronics is assumed to be due to magnetic linkage from the transient currents flowing as a result of the discharge transient. The behavior of a spinning spacecraft encountering a severe substorm is predicted using this technique. It is found that systems are potentially vulnerable to upset if transient signals enter through the ground lines.

  5. Characterization of electrical appliances in transient state

    NASA Astrophysics Data System (ADS)

    Wójcik, Augustyn; Winiecki, Wiesław

    2017-08-01

    The article contains the study about electrical appliance characterization on the basis of power grid signals. To represent devices, parameters of current and voltage signals recorded during transient states are used. In this paper only transients occurring as a result of switching on devices are considered. The way of data acquisition performed in specialized measurement setup developed for electricity load monitoring is described. The paper presents the method of transients detection and the method of appliance parameters calculation. Using the set of acquired measurement data and appropriate software the set of parameters for several household appliances operating in different operating conditions was processed. Usefulness of appliances characterization in Non-Intrusive Appliance Load Monitoring System (NIALMS) with the use of proposed method is discussed focusing on obtained results.

  6. Earthquake triggering by transient and static deformations

    Gomberg, J.; Beeler, N.M.; Blanpied, M.L.; Bodin, P.

    1998-01-01

    Observational evidence for both static and transient near-field and far-field triggered seismicity are explained in terms of a frictional instability model, based on a single degree of freedom spring-slider system and rate- and state-dependent frictional constitutive equations. In this study a triggered earthquake is one whose failure time has been advanced by ??t (clock advance) due to a stress perturbation. Triggering stress perturbations considered include square-wave transients and step functions, analogous to seismic waves and coseismic static stress changes, respectively. Perturbations are superimposed on a constant background stressing rate which represents the tectonic stressing rate. The normal stress is assumed to be constant. Approximate, closed-form solutions of the rate-and-state equations are derived for these triggering and background loads, building on the work of Dieterich [1992, 1994]. These solutions can be used to simulate the effects of static and transient stresses as a function of amplitude, onset time t0, and in the case of square waves, duration. The accuracies of the approximate closed-form solutions are also evaluated with respect to the full numerical solution and t0. The approximate solutions underpredict the full solutions, although the difference decreases as t0, approaches the end of the earthquake cycle. The relationship between ??t and t0 differs for transient and static loads: a static stress step imposed late in the cycle causes less clock advance than an equal step imposed earlier, whereas a later applied transient causes greater clock advance than an equal one imposed earlier. For equal ??t, transient amplitudes must be greater than static loads by factors of several tens to hundreds depending on t0. We show that the rate-and-state model requires that the total slip at failure is a constant, regardless of the loading history. Thus a static load applied early in the cycle, or a transient applied at any time, reduces the stress

  7. Turbofan compressor dynamics during afterburner transients

    NASA Technical Reports Server (NTRS)

    Kurkov, A. P.

    1975-01-01

    The effects of afterburner light-off and shut-down transients on compressor stability were investigated. Experimental results are based on detailed high-response pressure and temperature measurements on the Tf30-p-3 turbofan engine. The tests were performed in an altitude test chamber simulating high-altitude engine operation. It is shown that during both types of transients, flow breaks down in the forward part of the fan-bypass duct. At a sufficiently low engine inlet pressure this resulted in a compressor stall. Complete flow breakdown within the compressor was preceded by a rotating stall. At some locations in the compressor, rotating stall cells initially extended only through part of the blade span. For the shutdown transient, the time between first and last detected occurrence of rotating stall is related to the flow Reynolds number. An attempt was made to deduce the number and speed of propagation of rotating stall cells.

  8. The Fourier analysis of biological transients.

    PubMed

    Harris, C M

    1998-08-31

    With modern computing technology the digital implementation of the Fourier transform is widely available, mostly in the form of the fast Fourier transform (FFT). Although the FFT has become almost synonymous with the Fourier transform, it is a fast numerical technique for computing the discrete Fourier transform (DFT) of a finite sequence of sampled data. The DFT is not directly equivalent to the continuous Fourier transform of the underlying biological signal, which becomes important when analyzing biological transients. Although this distinction is well known by some, for many it leads to confusion in how to interpret the FFT of biological data, and in how to precondition data so as to yield a more accurate Fourier transform using the FFT. We review here the fundamentals of Fourier analysis with emphasis on the analysis of transient signals. As an example of a transient, we consider the human saccade to illustrate the pitfalls and advantages of various Fourier analyses.

  9. Transient Seepage for Levee Engineering Analyses

    NASA Astrophysics Data System (ADS)

    Tracy, F. T.

    2017-12-01

    Historically, steady-state seepage analyses have been a key tool for designing levees by practicing engineers. However, with the advances in computer modeling, transient seepage analysis has become a potentially viable tool. A complication is that the levees usually have partially saturated flow, and this is significantly more complicated in transient flow. This poster illustrates four elements of our research in partially saturated flow relating to the use of transient seepage for levee design: (1) a comparison of results from SEEP2D, SEEP/W, and SLIDE for a generic levee cross section common to the southeastern United States; (2) the results of a sensitivity study of varying saturated hydraulic conductivity, the volumetric water content function (as represented by van Genuchten), and volumetric compressibility; (3) a comparison of when soils do and do not exhibit hysteresis, and (4) a description of proper and improper use of transient seepage in levee design. The variables considered for the sensitivity and hysteresis studies are pore pressure beneath the confining layer at the toe, the flow rate through the levee system, and a levee saturation coefficient varying between 0 and 1. Getting results for SEEP2D, SEEP/W, and SLIDE to match proved more difficult than expected. After some effort, the results matched reasonably well. Differences in results were caused by various factors, including bugs, different finite element meshes, different numerical formulations of the system of nonlinear equations to be solved, and differences in convergence criteria. Varying volumetric compressibility affected the above test variables the most. The levee saturation coefficient was most affected by the use of hysteresis. The improper use of pore pressures from a transient finite element seepage solution imported into a slope stability computation was found to be the most grievous mistake in using transient seepage in the design of levees.

  10. Hardware-Abbildung eines videobasierten Verfahrens zur echtzeitfähigen Auswertung von Winkelhistogrammen auf eine modulare Coprozessor-Architektur

    NASA Astrophysics Data System (ADS)

    Flatt, H.; Tarnowsky, A.; Blume, H.; Pirsch, P.

    2010-10-01

    Dieser Beitrag behandelt die Abbildung eines videobasierten Verfahrens zur echtzeitfähigen Auswertung von Winkelhistogrammen auf eine modulare Coprozessor-Architektur. Die Architektur besteht aus mehreren dedizierten Recheneinheiten zur parallelen Verarbeitung rechenintensiver Bildverarbeitungsverfahren und ist mit einem RISC-Prozessor verbunden. Eine konfigurierbare Architekturerweiterung um eine Recheneinheit zur Auswertung von Winkelhistogrammen von Objekten ermöglicht in Verbindung mit dem RISC eine echtzeitfähige Klassifikation. Je nach Konfiguration sind für die Architekturerweiterung auf einem Xilinx Virtex-5-FPGA zwischen 3300 und 12 000 Lookup-Tables erforderlich. Bei einer Taktfrequenz von 100 MHz können unabhängig von der Bildauflösung pro Einzelbild in einem 25-Hz-Videodatenstrom bis zu 100 Objekte der Größe 256×256 Pixel analysiert werden. This paper presents the mapping of a video-based approach for real-time evaluation of angular histograms on a modular coprocessor architecture. The architecture comprises several dedicated processing elements for parallel processing of computation-intensive image processing tasks and is coupled with a RISC processor. A configurable architecture extension, especially a processing element for evaluating angular histograms of objects in conjunction with a RISC processor, provides a real-time classification. Depending on the configuration of the architecture extension, 3 300 to 12 000 look-up tables are required for a Xilinx Virtex-5 FPGA implementation. Running at a clock frequency of 100 MHz and independently of the image resolution per frame, 100 objects of size 256×256 pixels are analyzed in a 25 Hz video stream by the architecture.

  11. Transient analysis using conical shell elements

    NASA Technical Reports Server (NTRS)

    Yang, J. C. S.; Goeller, J. E.; Messick, W. T.

    1973-01-01

    The use of the NASTRAN conical shell element in static, eigenvalue, and direct transient analyses is demonstrated. The results of a NASTRAN static solution of an externally pressurized ring-stiffened cylinder agree well with a theoretical discontinuity analysis. Good agreement is also obtained between the NASTRAN direct transient response of a uniform cylinder to a dynamic end load and one-dimensional solutions obtained using a method of characteristics stress wave code and a standing wave solution. Finally, a NASTRAN eigenvalue analysis is performed on a hydroballistic model idealized with conical shell elements.

  12. Computer animation of modal and transient vibrations

    NASA Technical Reports Server (NTRS)

    Lipman, Robert R.

    1987-01-01

    An interactive computer graphics processor is described that is capable of generating input to animate modal and transient vibrations of finite element models on an interactive graphics system. The results from NASTRAN can be postprocessed such that a three dimensional wire-frame picture, in perspective, of the finite element mesh is drawn on the graphics display. Modal vibrations of any mode shape or transient motions over any range of steps can be animated. The finite element mesh can be color-coded by any component of displacement. Viewing parameters and the rate of vibration of the finite element model can be interactively updated while the structure is vibrating.

  13. Optical Transient Monitor (OTM) for BOOTES Project

    NASA Astrophysics Data System (ADS)

    Páta, P.; Bernas, M.; Castro-Tirado, A. J.; Hudec, R.

    2003-04-01

    The Optical Transient Monitor (OTM) is a software for control of three wide and ultra-wide filed cameras of BOOTES (Burst Observer and Optical Transient Exploring System) station. The OTM is a PC based and it is powerful tool for taking images from two SBIG CCD cameras in same time or from one camera only. The control program for BOOTES cameras is Windows 98 or MSDOS based. Now the version for Windows 2000 is prepared. There are five main supported modes of work. The OTM program could control cameras and evaluate image data without human interaction.

  14. Transient thermal camouflage and heat signature control

    NASA Astrophysics Data System (ADS)

    Yang, Tian-Zhi; Su, Yishu; Xu, Weikai; Yang, Xiao-Dong

    2016-09-01

    Thermal metamaterials have been proposed to manipulate heat flux as a new way to cloak or camouflage objects in the infrared world. To date, however, thermal metamaterials only operate in the steady-state and exhibit detectable, transient heat signatures. In this letter, the theoretical basis for a thermal camouflaging technique with controlled transient diffusion is presented. This technique renders an object invisible in real time. More importantly, the thermal camouflaging device instantaneously generates a pre-designed heat signature and behaves as a perfect thermal illusion device. A metamaterial coating with homogeneous and isotropic thermal conductivity, density, and volumetric heat capacity was fabricated and very good camouflaging performance was achieved.

  15. Transient astronomy with the Gaia satellite.

    PubMed

    Hodgkin, Simon T; Wyrzykowski, Łukasz; Blagorodnova, Nadejda; Koposov, Sergey

    2013-06-13

    Gaia is a cornerstone European Space Agency astrometry space mission and a successor to the Hipparcos mission. Gaia will observe the whole sky for 5 years, providing a serendipitous opportunity for the discovery of large numbers of transient and anomalous events, e.g. supernovae, novae and microlensing events, gamma-ray burst afterglows, fallback supernovae, as well as theoretical or unexpected phenomena. In this paper, we discuss our preparations to use Gaia to search for transients at optical wavelengths, and briefly describe the early detection, classification and prompt publication of anomalous sources.

  16. Real-time Recovery Efficiencies and Performance of the Palomar Transient Factory's Transient Discovery Pipeline

    SciT

    Frohmaier, C.; Sullivan, M.; Nugent, P. E.

    In this paper, we present the transient source detection efficiencies of the Palomar Transient Factory (PTF), parameterizing the number of transients that PTF found versus the number of similar transients that occurred over the same period in the survey search area but were missed. PTF was an optical sky survey carried out with the Palomar 48 inch telescope over 2009–2012, observing more than 8000 square degrees of sky with cadences of between one and five days, locating around 50,000 non-moving transient sources, and spectroscopically confirming around 1900 supernovae. We assess the effectiveness with which PTF detected transient sources, by insertingmore » $$\\simeq 7$$ million artificial point sources into real PTF data. We then study the efficiency with which the PTF real-time pipeline recovered these sources as a function of the source magnitude, host galaxy surface brightness, and various observing conditions (using proxies for seeing, sky brightness, and transparency). The product of this study is a multi-dimensional recovery efficiency grid appropriate for the range of observing conditions that PTF experienced and that can then be used for studies of the rates, environments, and luminosity functions of different transient types using detailed Monte Carlo simulations. Finally, we illustrate the technique using the observationally well-understood class of type Ia supernovae.« less

  17. Real-time Recovery Efficiencies and Performance of the Palomar Transient Factory's Transient Discovery Pipeline

    DOE PAGES

    Frohmaier, C.; Sullivan, M.; Nugent, P. E.; ...

    2017-05-09

    In this paper, we present the transient source detection efficiencies of the Palomar Transient Factory (PTF), parameterizing the number of transients that PTF found versus the number of similar transients that occurred over the same period in the survey search area but were missed. PTF was an optical sky survey carried out with the Palomar 48 inch telescope over 2009–2012, observing more than 8000 square degrees of sky with cadences of between one and five days, locating around 50,000 non-moving transient sources, and spectroscopically confirming around 1900 supernovae. We assess the effectiveness with which PTF detected transient sources, by insertingmore » $$\\simeq 7$$ million artificial point sources into real PTF data. We then study the efficiency with which the PTF real-time pipeline recovered these sources as a function of the source magnitude, host galaxy surface brightness, and various observing conditions (using proxies for seeing, sky brightness, and transparency). The product of this study is a multi-dimensional recovery efficiency grid appropriate for the range of observing conditions that PTF experienced and that can then be used for studies of the rates, environments, and luminosity functions of different transient types using detailed Monte Carlo simulations. Finally, we illustrate the technique using the observationally well-understood class of type Ia supernovae.« less

  18. Searching for MHz Transients with the VLA Low-band Ionosphere and Transient Experiment (VLITE)

    NASA Astrophysics Data System (ADS)

    Polisensky, Emil; Peters, Wendy; Giacintucci, Simona; Clarke, Tracy; Kassim, Namir E.; hyman, Scott D.; van der Horst, Alexander; Linford, Justin; Waldron, Zach; Frail, Dale

    2018-01-01

    NRL and NRAO have expanded the low frequency capabilities of the VLA through the VLA Low-band Ionosphere and Transient Experiment (VLITE, http://vlite.nrao.edu/ ), effectively making the instrument two telescopes in one. VLITE is a commensal observing system that harvests data from the prime focus in parallel with normal Cassegrain focus observing on a subset of VLA antennas. VLITE provides over 6000 observing hours per year in a > 5 square degree field-of-view using 64 MHz bandwidth centered on 352 MHz. By operating in parallel, VLITE offers invaluable low frequency data to targeted observations of transient sources detected at higher frequencies. With arcsec resolution and mJy sensitivity, VLITE additionally offers great potential for blind searches of rarer radio-selected transients. We use catalog matching software on the imaging products from the daily astrophysics pipeline and the LOFAR Transients Pipeline (TraP) on repeated observations of the same fields to search for coherent and incoherent astronomical transients on timescales of a few seconds to years. We present the current status of the VLITE transient science program from its initial deployment on 10 antennas in November 2014 through its expansion to 16 antennas in the summer of 2017. Transient limits from VLITE’s first year of operation (Polisensky et al. 2016) are updated per the most recent analysis.

  19. RFI flagging implications for short-duration transients

    NASA Astrophysics Data System (ADS)

    Cendes, Y.; Prasad, P.; Rowlinson, A.; Wijers, R. A. M. J.; Swinbank, J. D.; Law, C. J.; van der Horst, A. J.; Carbone, D.; Broderick, J. W.; Staley, T. D.; Stewart, A. J.; Huizinga, F.; Molenaar, G.; Alexov, A.; Bell, M. E.; Coenen, T.; Corbel, S.; Eislöffel, J.; Fender, R.; Grießmeier, J.-M.; Jonker, P.; Kramer, M.; Kuniyoshi, M.; Pietka, M.; Stappers, B.; Wise, M.; Zarka, P.

    2018-04-01

    With their wide fields of view and often relatively long coverage of any position in the sky in imaging survey mode, modern radio telescopes provide a data stream that is naturally suited to searching for rare transients. However, Radio Frequency Interference (RFI) can show up in the data stream in similar ways to such transients, and thus the normal pre-treatment of filtering RFI (flagging) may also remove astrophysical transients from the data stream before imaging. In this paper we investigate how standard flagging affects the detectability of such transients by examining the case of transient detection in an observing mode used for Low Frequency Array (LOFAR; van Haarlem et al., 2013) surveys. We quantify the fluence range of transients that would be detected, and the reduction of their SNR due to partial flagging. We find that transients with a duration close to the integration sampling time, as well as bright transients with durations on the order of tens of seconds, are completely flagged. For longer transients on the order of several tens of seconds to minutes, the flagging effects are not as severe, although part of the signal is lost. For these transients, we present a modified flagging strategy which mitigates the effect of flagging on transient signals. We also present a script which uses the differences between the two strategies, and known differences between transient RFI and astrophysical transients, to notify the observer when a potential transient is in the data stream.

  20. Detecting aseismic strain transients from seismicity data

    Llenos, A.L.; McGuire, J.J.

    2011-01-01

    Aseismic deformation transients such as fluid flow, magma migration, and slow slip can trigger changes in seismicity rate. We present a method that can detect these seismicity rate variations and utilize these anomalies to constrain the underlying variations in stressing rate. Because ordinary aftershock sequences often obscure changes in the background seismicity caused by aseismic processes, we combine the stochastic Epidemic Type Aftershock Sequence model that describes aftershock sequences well and the physically based rate- and state-dependent friction seismicity model into a single seismicity rate model that models both aftershock activity and changes in background seismicity rate. We implement this model into a data assimilation algorithm that inverts seismicity catalogs to estimate space-time variations in stressing rate. We evaluate the method using a synthetic catalog, and then apply it to a catalog of M???1.5 events that occurred in the Salton Trough from 1990 to 2009. We validate our stressing rate estimates by comparing them to estimates from a geodetically derived slip model for a large creep event on the Obsidian Buttes fault. The results demonstrate that our approach can identify large aseismic deformation transients in a multidecade long earthquake catalog and roughly constrain the absolute magnitude of the stressing rate transients. Our method can therefore provide a way to detect aseismic transients in regions where geodetic resolution in space or time is poor. Copyright 2011 by the American Geophysical Union.

  1. Inhomogeneous Forcing and Transient Climate Sensitivity

    NASA Technical Reports Server (NTRS)

    Shindell, Drew T.

    2014-01-01

    Understanding climate sensitivity is critical to projecting climate change in response to a given forcing scenario. Recent analyses have suggested that transient climate sensitivity is at the low end of the present model range taking into account the reduced warming rates during the past 10-15 years during which forcing has increased markedly. In contrast, comparisons of modelled feedback processes with observations indicate that the most realistic models have higher sensitivities. Here I analyse results from recent climate modelling intercomparison projects to demonstrate that transient climate sensitivity to historical aerosols and ozone is substantially greater than the transient climate sensitivity to CO2. This enhanced sensitivity is primarily caused by more of the forcing being located at Northern Hemisphere middle to high latitudes where it triggers more rapid land responses and stronger feedbacks. I find that accounting for this enhancement largely reconciles the two sets of results, and I conclude that the lowest end of the range of transient climate response to CO2 in present models and assessments (less than 1.3 C) is very unlikely.

  2. Transient global amnesia—a hippocampal phenomenon?

    PubMed Central

    Ponsford, J L; Donnan, G A

    1980-01-01

    A case of transient global amnesia of clear vascular aetiology is described. Results of neuropsychological testing carried out during the attack clarify the nature of the memory disorder and suggest that the critical region of ischaemia is the medial temporal area around the hippocampus. Follow-up testing suggests that no lasting memory impairment resulted. PMID:7373328

  3. Transient neuropathic bladder following herpes simplex genitalis.

    PubMed

    Riehle, R A; Williams, J J

    1979-08-01

    A case of transient bladder dysfunction and urinary retention concomitant with herpes genitalis is presented. The protean manifestations of the herpes simplex virus, the similar neurotropic behavior of simplex and zoster, and the neurologic sequelae of the cutaneous simplex eruption are discussed. The possibility of sacral radiculopathy after herpes genitalis must be considered when evaluating acute or episodic neurogenic bladders.

  4. Interpreting signals from astrophysical transient experiments

    PubMed Central

    O’Brien, Paul T.; Smartt, Stephen J.

    2013-01-01

    Time-domain astronomy has come of age with astronomers now able to monitor the sky at high cadence, both across the electromagnetic spectrum and using neutrinos and gravitational waves. The advent of new observing facilities permits new science, but the ever-increasing throughput of facilities demands efficient communication of coincident detections and better subsequent coordination among the scientific community so as to turn detections into scientific discoveries. To discuss the revolution occurring in our ability to monitor the Universe and the challenges it brings, on 25–26 April 2012, a group of scientists from observational and theoretical teams studying transients met with representatives of the major international transient observing facilities at the Kavli Royal Society International Centre, UK. This immediately followed the Royal Society Discussion Meeting ‘New windows on transients across the Universe’ held in London. Here, we present a summary of the Kavli meeting at which the participants discussed the science goals common to the transient astronomy community and analysed how to better meet the challenges ahead as ever more powerful observational facilities come on stream. PMID:23630383

  5. rfpipe: Radio interferometric transient search pipeline

    NASA Astrophysics Data System (ADS)

    Law, Casey J.

    2017-10-01

    rfpipe supports Python-based analysis of radio interferometric data (especially from the Very Large Array) and searches for fast radio transients. This extends on the rtpipe library (ascl:1706.002) with new approaches to parallelization, acceleration, and more portable data products. rfpipe can run in standalone mode or be in a cluster environment.

  6. Transient Non Lin Deformation in Fractured Rock

    SciT

    Sartori, Enrico

    1998-10-14

    MATLOC is a nonlinear, transient, two-dimensional (planer and axisymmetric), thermal stress, finite-element code designed to determine the deformation within a fractured rock mass. The mass is modeled as a nonlinear anistropic elastic material which can exhibit stress-dependent bi-linear locking behavior.

  7. Swift-BAT: Transient Source Monitoring

    NASA Astrophysics Data System (ADS)

    Barbier, L. M.; Barthelmy, S.; Cummings, J.; Gehrels, N.; Krimm, H.; Markwardt, C.; Mushotzky, R.; Parsons, A.; Sakamoto, T.; Tueller, J.; Fenimore, E.; Palmer, D.; Skinner, G.; Swift-BAT Team

    2005-12-01

    The Burst Alert Telescope (BAT) on the Swift satellite is a large field of view instrument that continually monitors the sky to provide the gamma-ray burst trigger for Swift. An average of more than 70% of the sky is observed on a daily basis. The survey mode data is processed on two sets of time scales: from one minute to one day as part of the transient monitor program, and from one spacecraft pointing ( ˜20 minutes) to the full mission duration for the hard X-ray survey program. In the transient monitor program, sky images are processed to detect astrophysical sources in six energy bands covering 15-350 keV. The detected flux or upper limit in each energy band is calculated for >300 objects on time scales up to one day. In addition, the monitor is sensitive to an outburst from a new or unknown source. Sensitivity as a function of time scale for catalog and unknown sources will be presented. The daily exposure for a typical source is ˜1500 - 3000 seconds, with a 1-sigma sensitivity of ˜4mCrab. 90% of the sources are sampled at least every 16 days, but many sources are sampled daily. The BAT team will soon make the results of the transient monitor public to the astrophysical community through the Swift mission web page. It is expected that the Swift-BAT transient monitor will become an important resource for the high energy astrophysics community.

  8. Video Storytelling in a Transient, Volunteer Organization

    ERIC Educational Resources Information Center

    Katzeff, Cecilia; Ware, Vanessa

    2007-01-01

    To make sense of and learn about work environments, people actively construct their own knowledge and share stories of their experience. Telling stories is particularly challenging in a transient organization where people are hired on a voluntary, temporary basis. Such is the case of a nonprofit music festival organization in Sweden, which is…

  9. Understanding of Particle Acceleration by Foreshock Transients

    NASA Astrophysics Data System (ADS)

    Liu, T. Z.; Angelopoulos, V.; Hietala, H.; Lu, S.; Wilson, L. B., III

    2017-12-01

    Although plasma shocks are known to be a major particle accelerator at Earth's environment (e.g., the bow shock) and elsewhere in the universe, how particles are accelerated to very large energies compared to the shock potential is still not fully understood. Significant new information on such acceleration in the vicinity of Earth's bow shock has recently emerged due to the availability of multi-point observations, in particular from Cluster and THEMIS. These have revealed numerous types of foreshock transients, formed by shock-reflected ions, which could play a crucial role in particle pre-acceleration, i.e. before the particles reach the shock to be subjected again to even further acceleration. Foreshock bubbles (FBs) and hot flow anomalies (HFAs), are a subset of such foreshock transients that are especially important due to their large spatial scale (1-10 Earth radii), and their ability to have global effects at Earth's geospace. These transients can accelerate particles that can become a particle source for the parent shock. Here we introduce our latest progress in understanding particle acceleration by foreshock transients including their statistical characteristics and acceleration mechanisms.

  10. Intermittent/transient faults in digital systems

    NASA Technical Reports Server (NTRS)

    Masson, G. M.; Glazer, R. E.

    1982-01-01

    Containment set techniques are applied to 8085 microprocessor controllers so as to transform a typical control system into a slightly modified version, shown to be crashproof: after the departure of the intermittent/transient fault, return to one proper control algorithm is assured, assuming no permanent faults occur.

  11. Interpreting signals from astrophysical transient experiments.

    PubMed

    O'Brien, Paul T; Smartt, Stephen J

    2013-06-13

    Time-domain astronomy has come of age with astronomers now able to monitor the sky at high cadence, both across the electromagnetic spectrum and using neutrinos and gravitational waves. The advent of new observing facilities permits new science, but the ever-increasing throughput of facilities demands efficient communication of coincident detections and better subsequent coordination among the scientific community so as to turn detections into scientific discoveries. To discuss the revolution occurring in our ability to monitor the Universe and the challenges it brings, on 25-26 April 2012, a group of scientists from observational and theoretical teams studying transients met with representatives of the major international transient observing facilities at the Kavli Royal Society International Centre, UK. This immediately followed the Royal Society Discussion Meeting 'New windows on transients across the Universe' held in London. Here, we present a summary of the Kavli meeting at which the participants discussed the science goals common to the transient astronomy community and analysed how to better meet the challenges ahead as ever more powerful observational facilities come on stream.

  12. Transient hypothyroidism after withdrawal of thyroxin therapy

    PubMed Central

    Distiller, L. A.; Joffe, B. I.

    1975-01-01

    Continued administration of large doses of thyroid may not produce hyperthyroidism in euthyroid individuals. Cessation of prolonged high-dosage thyroid replacement can cause transient clinical and biochemical hypothyroidism owing to pituitary suppression. A case is recorded in which both these phenomena are well demonstrated. This case highlights these basic endocrinological principles. PMID:1197170

  13. Diuretics for transient tachypnoea of the newborn.

    PubMed

    Kassab, Manal; Khriesat, Wadah M; Anabrees, Jasim

    2015-11-21

    Transient tachypnoea of the newborn (TTN) results from delayed clearance of lung liquid and is a common cause of admission of full-term infants to neonatal intensive care units. The condition is particularly common after elective caesarean section. Conventional treatment involves appropriate oxygen administration and continuous positive airway pressure in some cases. Most infants receive antibiotic therapy. Hastening the clearance of lung liquid may shorten the duration of the symptoms and reduce complications. To determine whether diuretic administration reduces the duration of oxygen therapy and respiratory symptoms and shortens hospital stay in term infants presenting with transient tachypnoea of the newborn. An updated search was carried out in September 2015 of the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library issue 9, 2015), MEDLINE via Ovid, EMBASE, PubMed, and CINAHL via OVID. We included randomised and quasi-randomised controlled trials that compared the effect of diuretics administration versus placebo or no treatment in infants of less than seven days of age, born at 37 or more weeks of gestation with the clinical picture of transient tachypnoea of the newborn. We extracted and analysed data according to the methods outlined in the latest Cochrane Handbook for Systematic Reviews of Interventions. Two review authors assessed trial quality in each potentially eligible manuscript and two review authors extracted data. Our previous systematic review included two trials enrolling a total of 100 infants with transient tachypnoea of the newborn (Wiswell 1985; Karabayir 2006). The updated search revealed no new trials. Wiswell 1985 randomised 50 infants to receive either oral furosemide (2 mg/kg body weight at time of diagnosis followed by a 1 mg/kg dose 12 hours later if the tachypnoea persisted) or placebo. Karabayir 2006 randomised 50 infants to receive either intravenous furosemide (2 mg/kg body

  14. Organization of extratropical transients during El Nino

    SciT

    Hoerling, M.P.; Ting, Mingfang

    Four observed El Nino-Southern Oscillation (ENSO) events are studied to determine the mechanisms responsible for the anomalous extratropical atmospheric circulation during northern winter. A parallel analysis of a GCM's response to El Nino is performed in order to assess if similar mechanisms are operative in the model atmosphere. The observed stationary wave anomalies over the Pacific/North American (PNA) region are found to be similar during the four winters despite appreciable differences in sea surface temperatures. The anomalous transient vorticity fluxes are remarkably robust over the North Pacific during each even, with an eastward extension of the climatological storm track leadingmore » to strong cyclonic forcing near 40[degrees]N, 150[degrees]W. This forcing is in phase with the seasonal mean Aleutian trough anomaly suggesting the important of eddy-mean flow interaction. By comparison, the intersample variability of the GCM response over the PNA region is found to exceed the observed inter-El Nino variability. This stems primarily from a large variability in the model's anomalous transients over the North Pacific. Further analysis reveals that extratropical vorticity transients are the primary mechanism maintaining the stationary wave anomalies over the PNA region during all four observed ENSO winters. In the case of the GCM, the organization of transient eddies is ill defined over the North Pacific, a behavior indicative of model error. A physical model is proposed to explain the robustness of the tropical controlling influence of the extratropical transients in nature. A simple equatorial Pacific heat source directly forces a tropical anticyclone whose phase relative to the climatological tropical anticyclone leads to an eastward extension of the subtropical jet stream. This mechanism appears to be equally effective for a heat source located either in the central or eastern Pacific basin. 36 refs., 14 figs.« less

  15. On-Die Sensors for Transient Events

    NASA Astrophysics Data System (ADS)

    Suchak, Mihir Vimal

    Failures caused by transient electromagnetic events like Electrostatic Discharge (ESD) are a major concern for embedded systems. The component often failing is an integrated circuit (IC). Determining which IC is affected in a multi-device system is a challenging task. Debugging errors often requires sophisticated lab setups which require intentionally disturbing and probing various parts of the system which might not be easily accessible. Opening the system and adding probes may change its response to the transient event, which further compounds the problem. On-die transient event sensors were developed that require relatively little area on die, making them inexpensive, they consume negligible static current, and do not interfere with normal operation of the IC. These circuits can be used to determine the pin involved and the level of the event in the event of a transient event affecting the IC, thus allowing the user to debug system-level transient events without modifying the system. The circuit and detection scheme design has been completed and verified in simulations with Cadence Virtuoso environment. Simulations accounted for the impact of the ESD protection circuits, parasitics from the I/O pin, package and I/O ring, and included a model of an ESD gun to test the circuit's response to an ESD pulse as specified in IEC 61000-4-2. Multiple detection schemes are proposed. The final detection scheme consists of an event detector and a level sensor. The event detector latches on the presence of an event at a pad, to determine on which pin an event occurred. The level sensor generates current proportional to the level of the event. This current is converted to a voltage and digitized at the A/D converter to be read by the microprocessor. Detection scheme shows good performance in simulations when checked against process variations and different kind of events.

  16. The fast transient sky with Gaia

    NASA Astrophysics Data System (ADS)

    Wevers, Thomas; Jonker, Peter G.; Hodgkin, Simon T.; Kostrzewa-Rutkowska, Zuzanna; Harrison, Diana L.; Rixon, Guy; Nelemans, Gijs; Roelens, Maroussia; Eyer, Laurent; van Leeuwen, Floor; Yoldas, Abdullah

    2018-01-01

    The ESA Gaia satellite scans the whole sky with a temporal sampling ranging from seconds and hours to months. Each time a source passes within the Gaia field of view, it moves over 10 charge coupled devices (CCDs) in 45 s and a light curve with 4.5 s sampling (the crossing time per CCD) is registered. Given that the 4.5 s sampling represents a virtually unexplored parameter space in optical time domain astronomy, this data set potentially provides a unique opportunity to open up the fast transient sky. We present a method to start mining the wealth of information in the per CCD Gaia data. We perform extensive data filtering to eliminate known onboard and data processing artefacts, and present a statistical method to identify sources that show transient brightness variations on ≲2 h time-scales. We illustrate that by using the Gaia photometric CCD measurements, we can detect transient brightness variations down to an amplitude of 0.3 mag on time-scales ranging from 15 s to several hours. We search an area of ∼23.5 deg2 on the sky and find four strong candidate fast transients. Two candidates are tentatively classified as flares on M-dwarf stars, while one is probably a flare on a giant star and one potentially a flare on a solar-type star. These classifications are based on archival data and the time-scales involved. We argue that the method presented here can be added to the existing Gaia Science Alerts infrastructure for the near real-time public dissemination of fast transient events.

  17. Re-Imagining "Bildung Zur Humanität": How I Developed the Dialogos Approach to Practical Philosophy through Action Inquiry Research

    ERIC Educational Resources Information Center

    Helskog, Guro Hansen

    2015-01-01

    This paper presents an account of how I developed the Dialogos approach to practical philosophy through action inquiry research. The process of development is understood as a contribution to the reconstruction of the notion "Bildung zur Humanität" as an ideal in education. Core perspectives, traditions and purposes involved in the action…

  18. Zinc-Responsive Regulation of Alternative Ribosomal Protein Genes in Streptomyces coelicolor Involves Zur and σR▿ †

    PubMed Central

    Owen, Gillian A.; Pascoe, Ben; Kallifidas, Dimitris; Paget, Mark S. B.

    2007-01-01

    Streptomyces coelicolor contains paralogous versions of seven ribosomal proteins (S14, S18, L28, L31, L32, L33, and L36), which differ in their potential to bind structural zinc. The paralogues are termed C+ or C− on the basis of the presence or absence of putative cysteine ligands. Here, mutational studies suggest that the C− version of L31 can functionally replace its C+ paralogue only when expressed at an artificially elevated level. We show that the level of expression of four transcriptional units encoding C− proteins is elevated under conditions of zinc deprivation. Zur controls the expression of three transcriptional units (including rpmG2, rpmE2, rpmB2, rpsN2, rpmF2, and possibly rpsR2). Zur also controls the expression of the znuACB operon, which is predicted to encode a high-affinity zinc transport system. Surprisingly, the zinc-responsive control of the rpmG3-rpmJ2 operon is dictated by σR, a sigma factor that was previously shown to control the response to disulfide stress in S. coelicolor. The induction of σR activity during zinc limitation establishes an important link between thiol-disulfide metabolism and zinc homeostasis. PMID:17400736

  19. Zinc-responsive regulation of alternative ribosomal protein genes in Streptomyces coelicolor involves zur and sigmaR.

    PubMed

    Owen, Gillian A; Pascoe, Ben; Kallifidas, Dimitris; Paget, Mark S B

    2007-06-01

    Streptomyces coelicolor contains paralogous versions of seven ribosomal proteins (S14, S18, L28, L31, L32, L33, and L36), which differ in their potential to bind structural zinc. The paralogues are termed C(+) or C(-) on the basis of the presence or absence of putative cysteine ligands. Here, mutational studies suggest that the C(-) version of L31 can functionally replace its C(+) paralogue only when expressed at an artificially elevated level. We show that the level of expression of four transcriptional units encoding C(-) proteins is elevated under conditions of zinc deprivation. Zur controls the expression of three transcriptional units (including rpmG2, rpmE2, rpmB2, rpsN2, rpmF2, and possibly rpsR2). Zur also controls the expression of the znuACB operon, which is predicted to encode a high-affinity zinc transport system. Surprisingly, the zinc-responsive control of the rpmG3-rpmJ2 operon is dictated by sigma(R), a sigma factor that was previously shown to control the response to disulfide stress in S. coelicolor. The induction of sigma(R) activity during zinc limitation establishes an important link between thiol-disulfide metabolism and zinc homeostasis.

  20. Single Event Transients in Linear Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Buchner, Stephen; McMorrow, Dale

    2005-01-01

    On November 5, 2001, a processor reset occurred on board the Microwave Anisotropy Probe (MAP), a NASA mission to measure the anisotropy of the microwave radiation left over from the Big Bang. The reset caused the spacecraft to enter a safehold mode from which it took several days to recover. Were that to happen regularly, the entire mission would be compromised, so it was important to find the cause of the reset and, if possible, to mitigate it. NASA assembled a team of engineers that included experts in radiation effects to tackle the problem. The first clue was the observation that the processor reset occurred during a solar event characterized by large increases in the proton and heavy ion fluxes emitted by the sun. To the radiation effects engineers on the team, this strongly suggested that particle radiation might be the culprit, particularly when it was discovered that the reset circuit contained three voltage comparators (LM139). Previous testing revealed that large voltage transients, or glitches appeared at the output of the LM139 when it was exposed to a beam of heavy ions [NI96]. The function of the reset circuit was to monitor the supply voltage and to issue a reset command to the processor should the voltage fall below a reference of 2.5 V [PO02]. Eventually, the team of engineers concluded that ionizing particle radiation from the solar event produced a negative voltage transient on the output of one of the LM139s sufficiently large to reset the processor on MAP. Fortunately, as of the end of 2004, only two such resets have occurred. The reset on MAP was not the first malfunction on a spacecraft attributed to a transient. That occurred shortly after the launch of NASA s TOPEX/Poseidon satellite in 1992. It was suspected, and later confirmed, that an anomaly in the Earth Sensor was caused by a transient in an operational amplifier (OP-15) [KO93]. Over the next few years, problems on TDRS, CASSINI, [PR02] SOHO [HA99,HA01] and TERRA were also attributed

  1. Transient tracer applications in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Stöven, T.; Tanhua, T.; Hoppema, M.

    2014-10-01

    Transient tracers can be used to constrain the Inverse-Gaussian transit time distribution (IG-TTD) and thus provide information about ocean ventilation. Individual transient tracers have different time and application ranges which are defined by their atmospheric history (chronological transient tracers) or their decay rate (radioactive transient tracers). The classification ranges from tracers for highly ventilated water masses, e.g. sulfur hexafluoride (SF6), the decay of Tritium (δ3H) and to some extent also dichlorodifluoromethane (CFC-12) to tracers for less ventilated deep ocean basins, e.g. CFC-12, Argon-39 (39Ar) and radiocarbon (14C). The IG-TTD can be empirically constrained by using transient tracer couples with sufficiently different input functions. Each tracer couple has specific characteristics which influence the application limit of the IG-TTD. Here we provide an overview of commonly used transient tracer couples and their validity areas within the IG-TTD by using the concept of tracer age differences (TAD). New measured CFC-12 and SF6 data from a section along 10° E in the Southern Ocean in 2012 are presented. These are combined with a similar data set of 1998 along 6° E in the Southern Ocean as well as with 39Ar data from the early 1980s in the western Atlantic Ocean and the Weddell Sea for investigating the application limit of the IG-TTD and to analyze changes in ventilation in the Southern Ocean. We found that the IG-TTD can be constrained south to 46° S which corresponds to the Subantarctic Front (SAF) denoting the application limit. The constrained IG-TTD north of the SAF shows a slight increase in mean ages between 1998 and 2012 in the upper 1200 m between 42-46° S. The absence of SF6 inhibits ventilation analyses below this depth. The time lag analysis between the 1998 and 2012 data shows an increase in ventilation down to 1000 m and a steady ventilation between 2000 m-bottom south of the SAF between 51-55° S.

  2. New SPIRITS discoveries of Infrared Transients and Variables

    NASA Astrophysics Data System (ADS)

    Jencson, J. E.; Kasliwal, M. M.; Adams, S.; Cook, D.; Tinyanont, S.; Kwan, S.; Prince, T.; Lau, R. M.; Perley, D.; Masci, F.; Helou, G.; Armus, L.; Surace, J.; Dyk, S. D. Van; Cody, A.; Boyer, M. L.; Bond, H. E.; Monson, A.; Bally, J.; Khan, R.; Levesque, E.; Fox, O.; Williams, R.; Whitelock, P. A.; Mohamed, S.; Gehrz, R. D.; Amodeo, S.; Shenoy, D.; Carlon, R.; Cass, A.; Corgan, D.; Dykhoff, D.; Faella, J.; Gburek, T.; Smith, N.; Cantiello, M.; Langer, N.; Ofek, E.; Johansson, J.; Parthasarathy, M.; Hsiao, E.; Phillips, M.; Morrell, N.; Gonzalez, C.; Contreras, C.

    2017-10-01

    We report the discoveries of mid-infrared transients/strong variables found in the course of the Spitzer InfraRed Intensive Transients Survey (SPIRITS) using Spitzer Early Release Data (ATel #6644, #7929, #8688, #8940, #9434, #10171, #10172, #10488).

  3. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Coulter, D. A.; Pan, Y.-C.; Kilpatrick, C. D.; Foley, R. J.

    2017-06-01

    We report the following classifications of optical transients from spectroscopic observations with KOSMOS on the KPNO Mayall 4-m telescope. Targets were supplied by the Pan-STARRS Survey for Transients (PSST) and Gaia.

  4. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Pan, Y.-C.; Miller, J.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-04-01

    We report the following classifications of optical transients from spectroscopic observations with the KOSMOS on the Mayall telescope. Targets were supplied by the Pan-STARRS Survey for Transients (PSST).

  5. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Pan, Y.-C.; Narayan, G.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.; Smith, K. W.; Wright, D.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.

    2015-04-01

    We report the following classifications of optical transients from spectroscopic observations with the KOSMOS on the Mayall telescope. Targets were supplied by the Pan-STARRS Survey for Transients (PSST).

  6. Ultrafast triggered transient energy storage by atomic layer deposition into porous silicon for integrated transient electronics

    NASA Astrophysics Data System (ADS)

    Douglas, Anna; Muralidharan, Nitin; Carter, Rachel; Share, Keith; Pint, Cary L.

    2016-03-01

    Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics.Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics. Electronic supplementary information (ESI) available: (i) Experimental details for ALD and material fabrication, ellipsometry film thickness, preparation of gel electrolyte and separator, details for electrochemical measurements, HRTEM image of VOx coated porous silicon, Raman spectroscopy for VOx as-deposited as well as annealed in air for 1 hour at 450 °C, SEM and transient behavior dissolution tests of uniformly coated VOx on

  7. Steady and transient regimes in hydropower plants

    NASA Astrophysics Data System (ADS)

    Gajic, A.

    2013-12-01

    Hydropower plant that has been in operation for about 30 years has to be reconstructed. They have already installed 12 Kaplan turbines, the largest in the world at that time. The existing CAM relationship was determined based on hydraulic model tests and checked by efficiency on-site tests. It was also tested based on turbine bearing vibrations. In order to discover vibrations and long cracks on stay vanes detailed on-site measurements were performed. Influence of the modification of the trailing edges on the dynamic stresses of the stay vanes is also shown. In order to improve power output transient regimes were analyzed, both experimentally and numerically. Reversible hydropower plant, a pioneer in Europe since it was the first Pump storage power plant constructed with the highest head pump-turbines in the world. Analyses of transient regimes discover some problems with S-shaped characteristics coupled with non-symmetrical penstock.

  8. Transient photothermal spectra of plasmonic nanobubbles.

    PubMed

    Lukianova-Hleb, Ekaterina Y; Sassaroli, Elisabetta; Jones, Alicia; Lapotko, Dmitri O

    2012-03-13

    The photothermal efficacy of near-infrared gold nanoparticles (NP), nanoshells, and nanorods was studied under pulsed high-energy optical excitation in plasmonic nanobubble (PNB) mode as a function of the wavelength and duration of the excitation laser pulse. PNBs, transient vapor nanobubbles, were generated around individual and clustered overheated NPs in water and living cells. Transient PNBs showed two photothermal features not previously observed for NPs: the narrowing of the spectral peaks to 1 nm and the strong dependence of the photothermal efficacy upon the duration of the laser pulse. Narrow red-shifted (relative to those of NPs) near-infrared spectral peaks were observed for 70 ps excitation laser pulses, while longer sub- and nanosecond pulses completely suppressed near-infrared peaks and blue shifted the PNB generation to the visual range. Thus, PNBs can provide superior spectral selectivity over gold NPs under specific optical excitation conditions.

  9. Meteorological interpretation of transient LOD changes

    NASA Astrophysics Data System (ADS)

    Masaki, Y.

    2008-04-01

    The Earth’s spin rate is mainly changed by zonal winds. For example, seasonal changes in global atmospheric circulation and episodic changes accompanied with El Nĩ os are clearly detected n in the Length-of-day (LOD). Sub-global to regional meteorological phenomena can also change the wind field, however, their effects on the LOD are uncertain because such LOD signals are expected to be subtle and transient. In our previous study (Masaki, 2006), we introduced atmospheric pressure gradients in the upper atmosphere in order to obtain a rough picture of the meteorological features that can change the LOD. In this presentation, we compare one-year LOD data with meteorological elements (winds, temperature, pressure, etc.) and make an attempt to link transient LOD changes with sub-global meteorological phenomena.

  10. Transient Diabetes Insipidus Following Cardiopulmonary Bypass.

    PubMed

    Ekim, Meral; Ekim, Hasan; Yilmaz, Yunus Keser; Bolat, Ali

    2015-04-01

    Diabetes insipidus (DI) results from inadequate output of Antidiuretic Hormone (ADH) from the pituitary gland (central DI) or the inability of the kidney tubules to respond to ADH (nephrogenic DI). ADH is an octapeptide produced in the supraoptic and paraventricular nuclei of the hypothalamus and stored in the posterior lobe of the pituitary gland. Cardiopulmonary Bypass (CPB) has been shown to cause a six-fold increased circulating ADH levels 12 hours after surgery. However, in some cases, ADH release may be transiently suppressed due to cardioplegia (cardiac standstill) or CPB leading to DI. We present the postoperative course of a 60-year-old man who developed transient DI after CPB. He was successfully treated by applying nasal desmopressin therapy. Relevant biochemical parameters should be monitored closely in patients who produce excessive urine after open heart surgery.

  11. Automated source classification of new transient sources

    NASA Astrophysics Data System (ADS)

    Oertel, M.; Kreikenbohm, A.; Wilms, J.; DeLuca, A.

    2017-10-01

    The EXTraS project harvests the hitherto unexplored temporal domain information buried in the serendipitous data collected by the European Photon Imaging Camera (EPIC) onboard the ESA XMM-Newton mission since its launch. This includes a search for fast transients, missed by standard image analysis, and a search and characterization of variability in hundreds of thousands of sources. We present an automated classification scheme for new transient sources in the EXTraS project. The method is as follows: source classification features of a training sample are used to train machine learning algorithms (performed in R; randomForest (Breiman, 2001) in supervised mode) which are then tested on a sample of known source classes and used for classification.

  12. The SkyMapper Transient Survey

    NASA Astrophysics Data System (ADS)

    Scalzo, R. A.; Yuan, F.; Childress, M. J.; Möller, A.; Schmidt, B. P.; Tucker, B. E.; Zhang, B. R.; Onken, C. A.; Wolf, C.; Astier, P.; Betoule, M.; Regnault, N.

    2017-07-01

    The SkyMapper 1.3 m telescope at Siding Spring Observatory has now begun regular operations. Alongside the Southern Sky Survey, a comprehensive digital survey of the entire southern sky, SkyMapper will carry out a search for supernovae and other transients. The search strategy, covering a total footprint area of 2 000 deg2 with a cadence of ⩽5 d, is optimised for discovery and follow-up of low-redshift type Ia supernovae to constrain cosmic expansion and peculiar velocities. We describe the search operations and infrastructure, including a parallelised software pipeline to discover variable objects in difference imaging; simulations of the performance of the survey over its lifetime; public access to discovered transients; and some first results from the Science Verification data.

  13. A physically transient form of silicon electronics.

    PubMed

    Hwang, Suk-Won; Tao, Hu; Kim, Dae-Hyeong; Cheng, Huanyu; Song, Jun-Kyul; Rill, Elliott; Brenckle, Mark A; Panilaitis, Bruce; Won, Sang Min; Kim, Yun-Soung; Song, Young Min; Yu, Ki Jun; Ameen, Abid; Li, Rui; Su, Yewang; Yang, Miaomiao; Kaplan, David L; Zakin, Mitchell R; Slepian, Marvin J; Huang, Yonggang; Omenetto, Fiorenzo G; Rogers, John A

    2012-09-28

    A remarkable feature of modern silicon electronics is its ability to remain physically invariant, almost indefinitely for practical purposes. Although this characteristic is a hallmark of applications of integrated circuits that exist today, there might be opportunities for systems that offer the opposite behavior, such as implantable devices that function for medically useful time frames but then completely disappear via resorption by the body. We report a set of materials, manufacturing schemes, device components, and theoretical design tools for a silicon-based complementary metal oxide semiconductor (CMOS) technology that has this type of transient behavior, together with integrated sensors, actuators, power supply systems, and wireless control strategies. An implantable transient device that acts as a programmable nonantibiotic bacteriocide provides a system-level example.

  14. Transient ultrafast coherent spectroscopy of 2-propanol

    NASA Astrophysics Data System (ADS)

    Meiselman, Seth; Decamp, Matthew; Lorenz, Virginia

    We use transient coherent spontaneous Raman spectroscopy to measure the coherence lifetimes of vibrational states in liquid propanol. By creating single-photon-level collective excitations of the vibrational states in the system we observe coherence oscillations due to simultaneous excitation of the 2885 cm-1, 2938 cm-1, and 2976 cm-1 modes. These lifetimes and oscillation frequencies agree with frequency-domain lineshape measurements.

  15. iPTF report of bright transients

    NASA Astrophysics Data System (ADS)

    Cannella, Chris; Kuesters, Daniel; Ferretti, Raphael; Blagorodnova, Nadejda; Adams, Scott; Kupfer, Thomas; Neill, James D.; Walters, Richard; Yan, Lin; Kulkarni, Shri

    2017-02-01

    The intermediate Palomar Transient Factory (iPTF; ATel #4807) reports the following bright ( Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R), and RB5 (Wozniak et al. 2013AAS...22143105W).

  16. Validity of Darcy's law under transient conditions

    Mongan, C.E.

    1985-01-01

    Darcy 's Law, which describes fluid flow through porous materials, was developed for steady flow conditions. The validity of applying this law to transient flows has been mathematically verified for most ground-water flow conditions. The verification was accomplished through application of Hankel transforms to linearized Navier-Stokes equations which described flow in a small diameter cylindrical tube. The tube was chosen to represent a single pore in a porous medium. (USGS)

  17. Spectrum of Transient ASASSN-13at

    NASA Astrophysics Data System (ADS)

    Garnavich, Peter; Deal, Shanel

    2013-06-01

    We observed the transient ASASSN-13at (ATEL 5168) on June 28.3 (UT) with the Vatican Advanced Technology Telescope (VATT) and VATTSPEC instrument. The resulting spectrum covers the wavelength range between 365 nm and 750 nm with a resolution of 1100. The spectrum of ASASSN-13at shows a blue continuum with strong Balmer absorption lines. Helium absorption at 447 nm and 588 nm is also seen. Blue-shifted emission lines are visible within the Halpha and Hbeta absorption features.

  18. Nonlinear transient analysis via energy minimization

    NASA Technical Reports Server (NTRS)

    Kamat, M. P.; Knight, N. F., Jr.

    1978-01-01

    The formulation basis for nonlinear transient analysis of finite element models of structures using energy minimization is provided. Geometric and material nonlinearities are included. The development is restricted to simple one and two dimensional finite elements which are regarded as being the basic elements for modeling full aircraft-like structures under crash conditions. The results indicate the effectiveness of the technique as a viable tool for this purpose.

  19. The Zwicky Transient Facility Public Alert Stream

    NASA Astrophysics Data System (ADS)

    Masci, F.; Kulkarni, S. R.; Graham, M.; Prince, T.; Helou, G.

    2018-06-01

    The Zwicky Transient Facility (ZTF; ATel #11266) announces the start of public alerts. These alerts will originate from the ZTF public surveys (Bellm & Kulkarni 2017; Nature Astronomy 1, 71) as described at www.ztf.caltech.edu/page/msip Alerts are generated by the ZTF Science Data System housed at IPAC-Caltech (www.ipac.caltech.edu) using a realtime image-subtraction pipeline (Masci et al. 2018; www.ztf.caltech.edu/page/technical).

  20. Transient cortical blindness after coronary angiography.

    PubMed Central

    Parry, R; Rees, J R; Wilde, P

    1993-01-01

    Transient visual loss lasting three days developed after transfemoral coronary angiography in a 62 year old man. Computed tomography (CT) showed bilateral leakage of contrast medium into the occipital cortex. A repeat CT scan after his sight recovered showed clearance of contrast with no underlying infarction. A breakdown of the blood-brain barrier with direct neurotoxicity of the contrast media seemed to be the cause of these neurological changes after coronary angiography which apparently have not been reported before. Images PMID:8280526

  1. Sprites, elf transients, and positive ground strokes

    SciT

    Boccippio, D.J.; Boldi, R.; Williams, E.R.

    1995-08-25

    In two summertime mesoscale convective systems (MCSs), mesospheric optical sprite phenomena were often coincident with both large-amplitude positive cloud-to-ground lightning and transient Schumann resonance excitations of the entire Earth-ionosphere cavity. These observations, together with earlier studies of MCS electrification, suggest that sprites are triggered when the rapid removal of large quantities of positive charge from an areally extensive charge layer stresses the mesosphere to dielectric breakdown. 46 refs., 7 figs., 1 tab.

  2. The Zwicky Transient Facility (ZTF) begins

    NASA Astrophysics Data System (ADS)

    Kulkarni, S. R.

    2018-02-01

    S. R. Kulkarni on behalf of the Zwicky Transient Facility (ZTF) announces the first confirmed results from the project. ZTF is led by the California Institute of Technology, US and includes IPAC, US; Los Alamos National Laboratory, US; University of Maryland, US; University of Wisconsin at Milwaukee, US; University of Washington, US; Oskar-Klein Center of the University of Stockholm, Sweden; DESY and Humboldt University of Berlin, Germany; Weizmann Institute of Science, Israel; and the University System of Taiwan, Taiwan.

  3. Monitoring transients in low inductance circuits

    DOEpatents

    Guilford, R.P.; Rosborough, J.R.

    1985-10-21

    The instant invention relates to methods of and apparatus for monitoring transients in low inductance circuits and to a probe utilized to practice said method and apparatus. More particularly, the instant invention relates to methods of and apparatus for monitoring low inductance circuits, wherein the low inductance circuits include a pair of flat cable transmission lines. The instant invention is further directed to a probe for use in monitoring pairs of flat cable transmission lines.

  4. Transient and steady state viscoelastic rolling contact

    NASA Technical Reports Server (NTRS)

    Padovan, J.; Paramadilok, O.

    1985-01-01

    Based on moving total Lagrangian coordinates, a so-called traveling Hughes type contact strategy is developed. Employing the modified contact scheme in conjunction with a traveling finite element strategy, an overall solution methodology is developed to handle transient and steady viscoelastic rolling contact. To verify the scheme, the results of both experimental and analytical benchmarking is presented. The experimental benchmarking includes the handling of rolling tires up to their upper bound behavior, namely the standing wave response.

  5. High energy transients: The millisecond domain

    NASA Astrophysics Data System (ADS)

    Rao, A. R.

    2018-02-01

    The search for high energy transients in the millisecond domain has come to the focus in recent times due to the detection of gravitational wave events and the identification of fast radio bursts as cosmological sources. Here we highlight the sensitivity limitations in the currently operating hard X-ray telescopes and give some details of the search for millisecond events in the AstroSat CZT Imager data.

  6. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Transient test cycle generation. 86... (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1333-2010 Transient test cycle generation. (a) Generating transient test...

  7. 40 CFR 86.1333-90 - Transient test cycle generation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Transient test cycle generation. 86...) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1333-90 Transient test cycle generation. (a) The heavy-duty transient engine cycles for Otto...

  8. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Pan, Y.-C.; Downing, S.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-01-01

    We report the following classifications of optical transients from spectroscopic observations with the KOSMOS on the Mayall telescope. Targets were supplied by the All-Sky Automated Survey for Supernovae (ASAS-SN), Catalina Real-Time Transient Survey (CRTS) and the CBAT Transient Object Followup Reports.

  9. Aeroelastic Modeling of a Nozzle Startup Transient

    NASA Technical Reports Server (NTRS)

    Wang, Ten-See; Zhao, Xiang; Zhang, Sijun; Chen, Yen-Sen

    2014-01-01

    Lateral nozzle forces are known to cause severe structural damage to any new rocket engine in development during test. While three-dimensional, transient, turbulent, chemically reacting computational fluid dynamics methodology has been demonstrated to capture major side load physics with rigid nozzles, hot-fire tests often show nozzle structure deformation during major side load events, leading to structural damages if structural strengthening measures were not taken. The modeling picture is incomplete without the capability to address the two-way responses between the structure and fluid. The objective of this study is to develop a tightly coupled aeroelastic modeling algorithm by implementing the necessary structural dynamics component into an anchored computational fluid dynamics methodology. The computational fluid dynamics component is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, while the computational structural dynamics component is developed under the framework of modal analysis. Transient aeroelastic nozzle startup analyses at sea level were performed, and the computed transient nozzle fluid-structure interaction physics presented,

  10. Transient birefringence effects in electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Parshkov, O. M.

    2015-11-01

    We report the results of numerical modelling of transient birefringence that arises as a result of electromagnetically induced transparency on degenerate quantum transitions between the states with J = 0, 1 and 2 in the presence of the Doppler broadening of spectral lines. It is shown that in the case of a linearly polarised control field, the effect of transient birefringence leads to a decay of the input circularly polarised probe pulse into separate linearly polarised pulses inside a medium. In the case of a circularly polarised control field, the effect of transient birefringence manifests itself in a decay of the input linearly polarised probe pulse into separate circularly polarised pulses. It is shown that the distance that a probe pulse has to pass in a medium before decaying into subpulses is considerably greater in the first case than in the second. The influence of the input probe pulse power and duration on the process of spatial separation into individual pulses inside a medium is studied. A qualitative analysis of the obtained results is presented.

  11. Initial Implementation of Transient VERA-CS

    SciT

    Gerlach, Andrew; Kochunas, Brendan; Salko, Robert

    In this milestone the capabilities of both CTF and MPACT were extended to perform coupled transient calculations. This required several small changes in MPACT to setup the problems correctly, perform the edits correctly, and call the appropriate CTF interfaces in the right order. For CTF, revisions and corrections to the transient timestepping algorithm were made, as well as the addition of a new interface subroutine to allow MPACT to drive CTF at each timestep. With the modifications completed, the initial coupled capability was demonstrated on some problems used for code verification, a hypothetical small mini-core, and a Watts Bar demonstrationmore » problem. For each of these cases the results showed good agreement with the previous MPACT internal TH feedback model that relied on a simplified fuel heat conduction model and simplified coolant treatment. After the pulse the results are notably different as expected, where the effects of convection of heat to the coolant can be observed. Areas for future work were discussed, including assessment and development of the CTF dynamic fuel deformation and gap conductance models, addition of suitable transient boiling and CHF models for the rapid heating and cooling rates seen in RIAs, additional validation and demonstration work, and areas for improvement to the code input and output capabilities.« less

  12. Magnetic Flux Transients during Solar Flares

    NASA Astrophysics Data System (ADS)

    Balasubramaniam, K. S.; Delgado, F.; Hock, R. A.

    2013-12-01

    Solar flares result from the sudden release of energy stored in the magnetic field of the solar atmosphere, attributed to magnetic reconnection. In this work, we use line-of-sight magnetograms to study the changes in photospheric magnetic field during large solar flares. The magnetograms are derived from observations using NASA's Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory, and have a cadence of 3 minutes at a 0.5 arcsecond spatial resolution. We studied the inferred magnetic flux changes in 11 X-class flares from (2011-2012) and 26 M-class flares (2011). Of the 37 flares, 32 exhibited short-lived (less than 30 minutes) magnetic flux transients (MFTs) during the progress of the flare, similar to those by Maurya et al. (2012). We note that MFTs were co-temporal with GOES X-ray peaks. Flares with rapid rises (impulsive flares) had stronger transients while those with slower rises (gradual flares) had weak or no MFTs. Finally, flares with stronger GOES X-ray peaks (flare class) showed stronger MFTs. We believe that these changes are non-physical because the changes in the magnetic field are transient (the magnetic field returns to the pre-flare state) and coincide with the impulsive phase of the flare. This work supported by the US Airforce Office of Scientific Research and the AFRL/RV Space Scholar Program.

  13. Experimental Investigation of Transient Sublimator Performance

    NASA Technical Reports Server (NTRS)

    Sheth, Rubik B.; Stephan, Ryan A.; Leimkuehler, Thomas O.

    2012-01-01

    Sublimators have been used as heat rejection devices for a variety of space applications including the Apollo Lunar Module and the Extravehicular Mobility Unit (EMU). Sublimators typically operate with steady-state feedwater utilization at or near 100%. However, sublimators are currently being considered for operations in a cyclical topping mode, which represents a new mode of operation for sublimators. Sublimators can be used as a supplemental heat rejection device during mission phases where the environmental temperature or heat rejection requirement changes rapidly. This scenario may occur during low lunar orbit, low earth orbit, or other planetary orbits. In these mission phases, the need for supplemental heat rejection will vary between zero and some fraction of the overall heat load. In particular, supplemental heat rejection is required for the portion of the orbit where the radiative sink temperature exceeds the system setpoint temperature. This paper will describe the effects of these transient starts and stops on the feedwater utilization during various feedwater timing scenarios. Experimental data from various scenarios is analyzed to investigate feedwater consumption efficiency under the cyclical conditions. Start up utilization tests were conducted to better understand the transient performance. This paper also provides recommendations for future sublimator design and transient operation.

  14. Peculiar Behaviors of Faint Galactic Bulge Transients

    NASA Technical Reports Server (NTRS)

    Swank, J. H.

    2004-01-01

    The Rossi X-ray Timing Explorer PCA scans of the Galactic bulge (galactic longitude plus or minus 11 degrees) have detected 8 recent transients which have peak intensities of 10 to 400 mCrab. Some of the transient events have a fast rise and slow decay typical of accretion disk instabilities. It is common for these decays to be oscillatory, rather than steady, as if there are waves within the disk. There are also outbursts with symmetric light curves. In particular, the source in Terzan 2 which had a very long (decade) doubling of intensity peaking near the beginning of 1997, in 2004 has had two 30 day brightenings by a factor of 5 only 100 days apart. During each of these a burst was observed in snapshot observations near the peak. The source SLX 1735-269, also a burster, though not in our observations, has had irregularly repeated occurrences of fast swings between close to zero and 2-4 times normal. Some examples, such as the increase, drop, and slow recovery of GS 1826-238 suggest a change in the accretion disk such as emptying and refilling or a peculiar alignment. Follow up observations have provided deeper information about these transient sources and possible explanations for their behavior will be addressed.

  15. Transient Thermoelectric Solution Employing Green's Functions

    NASA Technical Reports Server (NTRS)

    Mackey, Jon; Sehirlioglu, Alp; Dynys, Fred

    2014-01-01

    The study works to formulate convenient solutions to the problem of a thermoelectric couple operating under a time varying condition. Transient operation of a thermoelectric will become increasingly common as thermoelectric technology permits applications in an increasing number of uses. A number of terrestrial applications, in contrast to steady-state space applications, can subject devices to time varying conditions. For instance thermoelectrics can be exposed to transient conditions in the automotive industry depending on engine system dynamics along with factors like driving style. In an effort to generalize the thermoelectric solution a Greens function method is used, so that arbitrary time varying boundary and initial conditions may be applied to the system without reformulation. The solution demonstrates that in thermoelectric applications of a transient nature additional factors must be taken into account and optimized. For instance, the materials specific heat and density become critical parameters in addition to the thermal mass of a heat sink or the details of the thermal profile, such as oscillating frequency. The calculations can yield the optimum operating conditions to maximize power output andor efficiency for a given type of device.

  16. TRANSIENT AMORPHOUS CALCIUM PHOSPHATE IN FORMING ENAMEL

    PubMed Central

    Beniash, Elia; Metzler, Rebecca A.; Lam, Raymond S.K.; Gilbert, P.U.P.A.

    2009-01-01

    Enamel, the hardest tissue in the body, begins as a three-dimensional network of nanometer size mineral particles, suspended in a protein gel. This mineral network serves as a template for mature enamel formation. To further understand the mechanisms of enamel formation we characterized the forming enamel mineral at an early secretory stage using x-ray absorption near-edge structure (XANES) spectromicroscopy, transmission electron microscopy (TEM), FTIR microspectroscopy and polarized light microscopy. We show that the newly formed enamel mineral is amorphous calcium phosphate (ACP), which eventually transforms into apatitic crystals. Interestingly, the size, shape and spatial organization of these amorphous mineral particles and older crystals are essentially the same, indicating that the mineral morphology and organization in enamel is determined prior to its crystallization. Mineralization via transient amorphous phases has been previously reported in chiton teeth, mollusk shells, echinoderm spicules and spines, and recent reports strongly suggest the presence transient amorphous mineral in forming vertebrate bones. The present finding of transient ACP in murine tooth enamel suggests that this strategy might be universal. PMID:19217943

  17. Transient Numerical Modeling of Catalytic Channels

    NASA Technical Reports Server (NTRS)

    Struk, Peter M.; Dietrich, Daniel L.; Miller, Fletcher J.; T'ien, James S.

    2007-01-01

    This paper presents a transient model of catalytic combustion suitable for isolated channels and monolith reactors. The model is a lumped two-phase (gas and solid) model where the gas phase is quasi-steady relative to the transient solid. Axial diffusion is neglected in the gas phase; lateral diffusion, however, is accounted for using transfer coefficients. The solid phase includes axial heat conduction and external heat loss due to convection and radiation. The combustion process utilizes detailed gas and surface reaction models. The gas-phase model becomes a system of stiff ordinary differential equations while the solid phase reduces, after discretization, into a system of stiff ordinary differential-algebraic equations. The time evolution of the system came from alternating integrations of the quasi-steady gas and transient solid. This work outlines the numerical model and presents some sensitivity studies on important parameters including internal transfer coefficients, catalytic surface site density, and external heat-loss (if applicable). The model is compared to two experiments using CO fuel: (1) steady-state conversion through an isothermal platinum (Pt) tube and (2) transient propagation of a catalytic reaction inside a small Pt tube. The model requires internal mass-transfer resistance to match the experiments at lower residence times. Under mass-transport limited conditions, the model reasonably predicted exit conversion using global mass-transfer coefficients. Near light-off, the model results did not match the experiment precisely even after adjustment of mass-transfer coefficients. Agreement improved for the first case after adjusting the surface kinetics such that the net rate of CO adsorption increased compared to O2. The CO / O2 surface mechanism came from a sub-set of reactions in a popular CH4 / O2 mechanism. For the second case, predictions improved for lean conditions with increased external heat loss or adjustment of the kinetics as in the

  18. Transient Postseismic Relaxation With Burger's Body Viscoelasticity

    NASA Astrophysics Data System (ADS)

    Hetland, E. A.; Hager, B. H.; O'Connell, R. J.

    2002-12-01

    Typical models used to investigate postseismic deformation are composed of an elastic layer over a Maxwell viscoelastic region. Geodetic observations made after a number of large earthquakes show a rapid exponential decay in postseismic velocity immediately after the rupture, followed by a more slowly decaying (or constant) velocity at a later time. Models of a Maxwell viscoelastic interior predict a single exponential postseismic velocity relaxation. To account for observed rapid, short-term relaxation decay, surprisingly low viscosities in the lower-crust or upper-mantle have been proposed. To model the difference in short and long time decay rates, the Maxwell element is sometimes modified to have a non-linear rheology, which results in a lower effective viscosity immediately after the rupture, evolving to a higher effective viscosity as the co-seismic stresses relax. Incorporation of models of after-slip in the lower crust on a down-dip extension of the fault have also had some success at modeling the above observations. When real rocks are subjected to a sudden change in stress or strain, e.g., that caused by an earthquake, they exhibit a transient response. The transient deformation is typically accommodated by grain boundary sliding and the longer-time deformation is accommodated by motion of dislocations. Both a short-term transient response and long-term steady creep are exhibited by a Burger's body, a Maxwell element (a spring in series with a viscous dash-pot) in series with a Voigt element (a spring in parallel with a viscous dash-pot). Typically the (transient) viscosity of the Voigt element is 10 - 100 times less than the (steady) viscosity of the Maxwell element. Thus, with a Burger's body, stress relaxation is a superposition of two exponential decays. For a model composed of an elastic layer over a viscoelastic region, the coseismic changes in stress (and strain) depend only on the elastic moduli, and are independent of the description of the

  19. Quantification of metabolically active transient storage (MATS) in two reaches with contrasting transient storage and ecosystem respiration

    Alba Argerich; Roy Haggerty; Eugènia Martí; Francesc Sabater; Jay Zarnetske

    2011-01-01

    Water transient storage zones are hotspots for metabolic activity in streams although the contribution of different types of transient storage zones to the whole�]reach metabolic activity is difficult to quantify. In this study we present a method to measure the fraction of the transient storage that is metabolically active (MATS) in two consecutive reaches...

  20. Transient fault behavior in a microprocessor: A case study

    NASA Technical Reports Server (NTRS)

    Duba, Patrick

    1989-01-01

    An experimental analysis is described which studies the susceptibility of a microprocessor based jet engine controller to upsets caused by current and voltage transients. A design automation environment which allows the run time injection of transients and the tracing from their impact device to the pin level is described. The resulting error data are categorized by the charge levels of the injected transients by location and by their potential to cause logic upsets, latched errors, and pin errors. The results show a 3 picoCouloumb threshold, below which the transients have little impact. An Arithmetic and Logic Unit transient is most likely to result in logic upsets and pin errors (i.e., impact the external environment). The transients in the countdown unit are potentially serious since they can result in latched errors, thus causing latent faults. Suggestions to protect the processor against these errors, by incorporating internal error detection and transient suppression techniques, are also made.

  1. Transient Pressure Test Article Test Program

    NASA Technical Reports Server (NTRS)

    Vibbart, Charles M.

    1989-01-01

    The Transient Pressure Test Article (TPTA) test program is being conducted at a new test facility located in the East Test Area at the National Aeronautics and Space Administration's (NASA's) Marshall Space Flight Center (MSFC) in Huntsville, Alabama. This facility, along with the special test equipment (STE) required for facility support, was constructed specifically to test and verify the sealing capability of the Redesigned Solid Rocket Motor (RSRM) field, igniter, and nozzle joints. The test article consists of full scale RSRM hardware loaded with inert propellant and assembled in a short stack configuration. The TPTA is pressurized by igniting a propellant cartridge capable of inducing a pressure rise rate which stimulates the ignition transient that occurs during launch. Dynamic loads are applied during the pressure cycle to simulate external tank attach (ETA) strut loads present on the ETA ring. Sealing ability of the redesigned joints is evaluated under joint movement conditions produced by these combined loads since joint sealing ability depends on seal resilience velocity being greater than gap opening velocity. Also, maximum flight dynamic loads are applied to the test article which is either pressurized to 600 psia using gaseous nitrogen (GN2) or applied to the test article as the pressure decays inside the test article on the down cycle after the ignition transient cycle. This new test facility is examined with respect to its capabilities. In addition, both the topic of test effectiveness versus space vehicle flight performance and new aerospace test techniques, as well as a comparison between the old SRM design and the RSRM are presented.

  2. Transient well flow in vertically heterogeneous aquifers

    NASA Astrophysics Data System (ADS)

    Hemker, C. J.

    1999-11-01

    A solution for the general problem of computing well flow in vertically heterogeneous aquifers is found by an integration of both analytical and numerical techniques. The radial component of flow is treated analytically; the drawdown is a continuous function of the distance to the well. The finite-difference technique is used for the vertical flow component only. The aquifer is discretized in the vertical dimension and the heterogeneous aquifer is considered to be a layered (stratified) formation with a finite number of homogeneous sublayers, where each sublayer may have different properties. The transient part of the differential equation is solved with Stehfest's algorithm, a numerical inversion technique of the Laplace transform. The well is of constant discharge and penetrates one or more of the sublayers. The effect of wellbore storage on early drawdown data is taken into account. In this way drawdowns are found for a finite number of sublayers as a continuous function of radial distance to the well and of time since the pumping started. The model is verified by comparing results with published analytical and numerical solutions for well flow in homogeneous and heterogeneous, confined and unconfined aquifers. Instantaneous and delayed drainage of water from above the water table are considered, combined with the effects of partially penetrating and finite-diameter wells. The model is applied to demonstrate that the transient effects of wellbore storage in unconfined aquifers are less pronounced than previous numerical experiments suggest. Other applications of the presented solution technique are given for partially penetrating wells in heterogeneous formations, including a demonstration of the effect of decreasing specific storage values with depth in an otherwise homogeneous aquifer. The presented solution can be a powerful tool for the analysis of drawdown from pumping tests, because hydraulic properties of layered heterogeneous aquifer systems with

  3. Sleep Modifications in Acute Transient Global Amnesia

    PubMed Central

    Della Marca, Giacomo; Mazza, Marianna; Losurdo, Anna; Testani, Elisa; Broccolini, Aldobrando; Frisullo, Giovanni; Marano, Giuseppe; Morosetti, Roberta; Pilato, Fabio; Profice, Paolo; Vollono, Catello; Di Lazzaro, Vincenzo

    2013-01-01

    Study Objective: Transient global amnesia (TGA) is a temporary memory loss characterized by an abrupt onset of antero-grade and retrograde amnesia, totally reversible. Since sleep plays a major role in memory consolidation, and in the storage of memory-related traces into the brain cortex, the aims of the present study were: (1) to evaluate changes in sleep macro-structure in TGA; (2) to assess modifications in sleep micro-structure in TGA, with particular reference to the arousal EEG and to cyclic alternating pattern (CAP); (3) to compare sleep parameters in TGA patients with a control group of patients with acute ischemic events (“minor stroke” or transient ischemic attack [TIA]) clinically and neuroradiologically “similar” to the TGA. Methods: TGA group: 17 patients, (8 men and 9 women, 60.2 ± 12.5 years). Stroke or TIA (SoT) group: 17 patients hospitalized in the Stroke Unit for recent onset of minor stroke or TIA with hemispheric localization; healthy controls (HC) group: 17 healthy volunteers, matched for age and sex. Patients and controls underwent full-night polysomnography. Results: In the multivariate analysis (conditions TGA, SoT, and HC) a significant effect of the condition was observed for sleep efficiency index, number of awakenings longer 1 min, REM latency, CAP time, and CAP rate. TGA and SoT differed only for CAP time and CAP rate, which were lower in the TGA group. Conclusions: Microstructural modification associated with TGA could be consequent to: (1) hippocampal dysfunction and memory impairment; (2) impairment of arousal-related structures (in particular, cholinergic pathways); (3) emotional distress. Citation: Della Marca G; Mazza M; Losurdo A; Testani E; Broccolini A; Frisullo G; Marano G; Morosetti R; Pilato F; Profice P; Vollono C; Di Lazzaro V. Sleep modifications in acute transient global amnesia. J Clin Sleep Med 2013;9(9):921-927. PMID:23997704

  4. Transient Electric Changes Immediately After Surgical Trauma

    PubMed Central

    Driban, Jeffrey B; Swanik, C. Buz; Huxel, Kellie C; Balsubramanian, Easwaran

    2007-01-01

    Context: Electric stimulation is frequently used to promote soft tissue healing, although we do not have a complete understanding of the tissue's electromagnetic properties. Objective: To measure the transient electric changes in skin and muscle tissue immediately after trauma. Design: 1-group time series. Setting: Climate-controlled operating room in a public urban hospital. Patients or Other Participants: Eleven participants (8 females, 3 males) with a mean age of 65.18 ± 11.36 years undergoing total hip arthroplasty. Intervention(s): An incision approximately 10 cm distal to the posterior superior iliac spine extended distally over the greater trochanter and along the lateral limb. The incision was completed in 2 cuts: (1) skin and subcutaneous fat and (2) muscle tissue. Main Outcome Measure(s): Three measurement sessions were performed with an electrometer before and after a skin incision and after a muscle incision. Potential differences and current intensity were measured immediately after acute trauma to determine the transient electric changes associated with soft tissue injury. Results: The electric potentials were significantly more negative after the skin incision (P = .036) and skin plus muscle incision (P = .008; preincision = 0.001 ± 0.015 V, skin incision = −0.127 ± 0.134 V, skin plus muscle incision = −0.192 ± 0.153V). Current intensity changed significantly after the skin plus muscle incision (P = .008; preincision = 0.046 ± 0.112 pA, skin incision = −0.803 ± 0.904 pA, skin plus muscle incision = −1.708 ± 1.302 pA). Conclusions: Soft tissue trauma generated negative transient electric changes. PMID:18174941

  5. Three Decades of Explosive High Energy Transients

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2013-01-01

    Gamma-Ray Bursts are the most brilliant explosions in space. The first GRB was discovered on 1967, just 40 years ago. It took several years and multiple generations of space and ground instruments to unravel some of the mysteries of this phenomenon. However, many questions remain open today. I will discuss the history, evolution and current status of the GRB field and its contributions in our understanding of the transient high energy sky. Finally, I will describe how GRBs can be utilized in future missions as tools, to probe the cosmic chemical evolution of the Universe and the star formation rates.

  6. Sustained Perceptual Deficits from Transient Sensory Deprivation

    PubMed Central

    Sanes, Dan H.

    2015-01-01

    Sensory pathways display heightened plasticity during development, yet the perceptual consequences of early experience are generally assessed in adulthood. This approach does not allow one to identify transient perceptual changes that may be linked to the central plasticity observed in juvenile animals. Here, we determined whether a brief period of bilateral auditory deprivation affects sound perception in developing and adult gerbils. Animals were reared with bilateral earplugs, either from postnatal day 11 (P11) to postnatal day 23 (P23) (a manipulation previously found to disrupt gerbil cortical properties), or from P23-P35. Fifteen days after earplug removal and restoration of normal thresholds, animals were tested on their ability to detect the presence of amplitude modulation (AM), a temporal cue that supports vocal communication. Animals reared with earplugs from P11-P23 displayed elevated AM detection thresholds, compared with age-matched controls. In contrast, an identical period of earplug rearing at a later age (P23-P35) did not impair auditory perception. Although the AM thresholds of earplug-reared juveniles improved during a week of repeated testing, a subset of juveniles continued to display a perceptual deficit. Furthermore, although the perceptual deficits induced by transient earplug rearing had resolved for most animals by adulthood, a subset of adults displayed impaired performance. Control experiments indicated that earplugging did not disrupt the integrity of the auditory periphery. Together, our results suggest that P11-P23 encompasses a critical period during which sensory deprivation disrupts central mechanisms that support auditory perceptual skills. SIGNIFICANCE STATEMENT Sensory systems are particularly malleable during development. This heightened degree of plasticity is beneficial because it enables the acquisition of complex skills, such as music or language. However, this plasticity comes with a cost: nervous system development

  7. Transient Heat Transfer in TCAP Coils

    SciT

    Steimke, J.L.

    1999-03-09

    The Thermal Cycling Absorption Process (TCAP) is used to separate isotopes of hydrogen. TCAP involves passing a stream of mixed hydrogen isotopes through palladium deposited on kieselguhr (Pd/k) while cycling the temperature of the Pd/k. Kieselguhr is a silica mineral also called diatomite. To aid in the design of a full scale facility, the Thermal Fluids Laboratory was used by the Chemical and Hydrogen Technology Section to compare the heat transfer properties of three different configurations of stainless steel coils containing kieselguhr and helium. Testing of coils containing Pd/k and hydrogen isotopes would have been more prototypical but would havemore » been too expensive. Three stainless steel coils filled with kieselguhr were tested; one made from 2.0 inch diameter tubing, one made from 2.0 inch diameter tubing with foam copper embedded in the kieselguhr and one made from 1.25 inch diameter tubing. It was known prior to testing that increasing the tubing diameter from 1.25 inch to 2.0 inch would slow the rate of temperature change. The primary purpose of the testing was to measure to what extent the presence of copper foam in a 2.0" tubing coil would compensate for the effect of larger diameter. Each coil was connected to a pressure gage and the coil was evacuated and backfilled with helium gas. Helium was used instead of a mixture of hydrogen isotopes for reasons of safety. Each coil was quickly immersed in a stirred bath of ethylene glycol at a temperature of approximately 100 degrees Celsius. The coil pressure increased, reflecting the increase in average temperature of its contents. The pressure transient was recored as a function of time after immersion. Because of the actual process will use Pd/k instead of kieselguhr, additional tests were run to determine the differences in thermal properties between the two materials. The method was to position a thermocouple at the center of a hollow sphere and pack the sphere with Pd/k. The sphere was sealed

  8. Transient Heat Transfer in TCAP Coils

    SciT

    Steimke, J.L.

    1999-03-09

    The Thermal Cycling Absorption Process (TCAP) is used to separate isotopes of hydrogen. TCAP involves passing a stream of mixed hydrogen isotopes through palladium deposited on kieselguhr (Pd/k) while cycling the temperature of the Pd/k. Kieselguhr is a silica mineral also called diatomite. To aid in the design of a full scale facility, the Thermal Fluids Laboratory was used by the Chemical and Hydrogen Technology Section to compare the heat transfer properties of three different configurations of stainless steel coils containing kieselguhr and helium. Testing of coils containing Pd/k and hydrogen isotopes would have been more prototypical but would havemore » been too expensive. Three stainless steel coils filled with kieselguhr were tested; one made from 2.0 inch diameter tubing, one made from 2.0 inch diameter tubing with foam copper embedded in the kieselguhr and one made from 1.25 inch diameter tubing. It was known prior to testing that increasing the tubing diameter from 1.25 inch to 2.0 inch would slow the rate of temperature change. The primary purpose of the testing was to measure to what extent the presence of copper foam in a 2.0 tubing coil would compensate for the effect of larger diameter. Each coil was connected to a pressure gage and the coil was evacuated and backfilled with helium gas. Helium was used instead of a mixture of hydrogen isotopes for reasons of safety. Each coil was quickly immersed in a stirred bath of ethylene glycol at a temperature of approximately 100 degrees Celsius. The coil pressure increased, reflecting the increase in average temperature of its contents. The pressure transient was recored as a function of time after immersion. Because of the actual process will use Pd/k instead of kieselguhr, additional tests were run to determine the differences in thermal properties between the two materials. The method was to position a thermocouple at the center of a hollow sphere and pack the sphere with Pd/k. The sphere was sealed

  9. Anode energy transfer in a transient arc

    NASA Astrophysics Data System (ADS)

    Valensi, F.; Ratovoson, P.; Razafinimanana, M.; Gleizes, A.

    2017-04-01

    This work deals with experimental investigation of a transient arc. Arc configuration and electrode erosion were studied in order to quantify the energy transfer to the electrodes as a function of maximal current, time constant and electrodes material. Experiments with two consecutive arcs allow demonstrating non stationary behaviour of the arc electrode interaction. This is due to the fact that while the duration of the experiments is far larger than plasma phenomena time constants, it is comparable to those of electrode heating and melting processes.

  10. Hardware Demonstration: Frequency Spectra of Transients

    NASA Technical Reports Server (NTRS)

    McCloskey, John; Dimov, Jen

    2017-01-01

    Radiated emissions measurements as specified by MIL-STD-461 are performed in the frequency domain, which is best suited to continuous wave (CW) types of signals. However, many platforms implement signals that are single event pulses or transients. Such signals can potentially generate momentary radiated emissions that can cause interference in the system, but they may be missed with traditional measurement techniques. This demonstration provides measurement and analysis techniques that effectively evaluate the potential emissions from such signals in order to evaluate their potential impacts to system performance.

  11. Transient upset models in computer systems

    NASA Technical Reports Server (NTRS)

    Mason, G. M.

    1983-01-01

    Essential factors for the design of transient upset monitors for computers are discussed. The upset is a system level event that is software dependent. It can occur in the program flow, the opcode set, the opcode address domain, the read address domain, and the write address domain. Most upsets are in the program flow. It is shown that simple, external monitors functioning transparently relative to the system operations can be built if a detailed accounting is made of the characteristics of the faults that can happen. Sample applications are provided for different states of the Z-80 and 8085 based system.

  12. Blade loss transient dynamic analysis of turbomachinery

    NASA Technical Reports Server (NTRS)

    Stallone, M. J.; Gallardo, V.; Storace, A. F.; Bach, L. J.; Black, G.; Gaffney, E. F.

    1982-01-01

    This paper reports on work completed to develop an analytical method for predicting the transient non-linear response of a complete aircraft engine system due to the loss of a fan blade, and to validate the analysis by comparing the results against actual blade loss test data. The solution, which is based on the component element method, accounts for rotor-to-casing rubs, high damping and rapid deceleration rates associated with the blade loss event. A comparison of test results and predicted response show good agreement except for an initial overshoot spike not observed in test. The method is effective for analysis of large systems.

  13. Transient sheath overvoltages in armored power cables

    SciT

    Gustavsen, B.; Sletbak, J.

    1996-07-01

    This paper is concerned with methods of limiting the build-up of transient voltages between sheath and armor in long armored power cables. Calculations by a frequency dependent cable model demonstrate that this voltage can be efficiently limited to an acceptable level by introducing sheath-armor bondings at regular intervals, or by using a semiconductive sheath-armor interlayer. The paper investigates the required minimum length between bondings, as well as the required conductivity of the sheath-armor interlayer if the use of bondings is to be avoided.

  14. X-ray Transients in M31

    NASA Astrophysics Data System (ADS)

    Kong, A. K. H.; Garcia, M. R.; Primini, F. A.; Murray, S. S.; McClintock, J. E.

    2002-06-01

    A bright X-ray transient was detected by Chandra on 2002 June 2 with a series of 5 HRC-I snapshots. The new source CXOU J004154.6+405648 (R.A.=00h41m54s.64, Dec.=+40d56m48s.0, +/- 1", J2000) is discovered at a luminosity (0.3-10 keV) of 1.5 x 1038 erg/s (assuming an absorbed power-law model with photon index = 2 and NH = 1021 cm-2 at a distance of 780 kpc).

  15. A Novel Detector of Broadband Transient Signals

    DTIC Science & Technology

    2006-11-01

    accroissement soudain de l’énergie spectrale observé pendant une courte période sur une vaste gamme de fréquences. Contrairement aux autres méthodes de...nombre d’applications différentes dans lesquelles les transitoires se manifestent sous forme d’un accroissement soudain de l’énergie spectrale observé...torpedo bearing error of 20 degrees (θ = θ1 + 20) was introduced (equation (16)). Al - though, in this case r2 was reduced, the two transients were

  16. Physical Origin of Transient Negative Capacitance in a Ferroelectric Capacitor

    NASA Astrophysics Data System (ADS)

    Chang, Sou-Chi; Avci, Uygar E.; Nikonov, Dmitri E.; Manipatruni, Sasikanth; Young, Ian A.

    2018-01-01

    Transient negative differential capacitance, the dynamic reversal of transient capacitance in an electrical circuit, is of highly technological and scientific interest since it probes the foundation of ferroelectricity. We study a resistor-ferroelectric capacitor (R -FEC) network through a series of coupled equations based on Kirchhoff's law, electrostatics, and Landau theory. We show that transient negative capacitance (NC) in a R -FEC circuit originates from the mismatch in switching rate between the free charge on the metal plate and the bound charge in a ferroelectric (FE) capacitor during the polarization switching. This transient free charge-polarization mismatch is driven by the negative curvature of the FE free-energy landscape, and it is also analytically shown that a free-energy profile with a negative curvature is the only physical system that can describe transient NC in a R -FEC circuit. Furthermore, transient NC induced by the free charge-polarization mismatch is justified by its dependence on both external resistance and the intrinsic FE viscosity coefficient. The depolarization effect on FE capacitors emphasizes the importance of negative curvature to transient NC and also implies that transient and steady-state NC cannot be observed in a FE capacitor simultaneously. Finally, using the transient NC measurements, a procedure to experimentally determine the viscosity coefficient is presented to provide more insight into the relation between transient NC and the FE free-energy profile.

  17. Optimal Transient Growth of Submesoscale Baroclinic Instabilities

    NASA Astrophysics Data System (ADS)

    White, Brian; Zemskova, Varvara; Passaggia, Pierre-Yves

    2016-11-01

    Submesoscale instabilities are analyzed using a transient growth approach to determine the optimal perturbation for a rotating Boussinesq fluid subject to baroclinic instabilities. We consider a base flow with uniform shear and stratification and consider the non-normal evolution over finite-time horizons of linear perturbations in an ageostrophic, non-hydrostatic regime. Stone (1966, 1971) showed that the stability of the base flow to normal modes depends on the Rossby and Richardson numbers, with instabilities ranging from geostrophic (Ro -> 0) and ageostrophic (finite Ro) baroclinic modes to symmetric (Ri < 1 , Ro > 1) and Kelvin-Helmholtz (Ri < 1 / 4) modes. Non-normal transient growth, initiated by localized optimal wave packets, represents a faster mechanism for the growth of perturbations and may provide an energetic link between large-scale flows in geostrophic balance and dissipation scales via submesoscale instabilities. Here we consider two- and three-dimensional optimal perturbations by means of direct-adjoint iterations of the linearized Boussinesq Navier-Stokes equations to determine the form of the optimal perturbation, the optimal energy gain, and the characteristics of the most unstable perturbation.

  18. Asteroids in the High Cadence Transient Survey

    NASA Astrophysics Data System (ADS)

    Peña, J.; Fuentes, C.; Förster, F.; Maureira, J. C.; San Martín, J.; Littín, J.; Huijse, P.; Cabrera-Vives, G.; Estévez, P. A.; Galbany, L.; González-Gaitán, S.; Martínez, J.; de Jaeger, Th.; Hamuy, M.

    2018-03-01

    We report on the serendipitous observations of solar system objects imaged during the High cadence Transient Survey 2014 observation campaign. Data from this high-cadence wide-field survey was originally analyzed for finding variable static sources using machine learning to select the most-likely candidates. In this work, we search for moving transients consistent with solar system objects and derive their orbital parameters. We use a simple, custom motion detection algorithm to link trajectories and assume Keplerian motion to derive the asteroid’s orbital parameters. We use known asteroids from the Minor Planet Center database to assess the detection efficiency of the survey and our search algorithm. Trajectories have an average of nine detections spread over two days, and our fit yields typical errors of {σ }a∼ 0.07 {au}, σ e ∼ 0.07 and σ i ∼ 0.°5 in semimajor axis, eccentricity, and inclination, respectively, for known asteroids in our sample. We extract 7700 orbits from our trajectories, identifying 19 near-Earth objects, 6687 asteroids, 14 Centaurs, and 15 trans-Neptunian objects. This highlights the complementarity of supernova wide-field surveys for solar system research and the significance of machine learning to clean data of false detections. It is a good example of the data-driven science that Large Synoptic Survey Telescope will deliver.

  19. Temperature-Centric Evaluation of Sensor Transients

    NASA Astrophysics Data System (ADS)

    Ayhan, Tuba; Muezzinoglu, Kerem; Vergara, Alexander; Yalcin, Mustak

    2011-09-01

    Controllable sensing conditions provide the means for diversifying sensor response and achieving better selectivity. Modulating the sensing layer temperature of metal-oxide sensors is a popular method for multiplexing the limited number of sensing elements that can be employed in a practical array. Time limitations in many applications, however, cannot tolerate an ad-hoc, one-size-fits-all modulation pattern. When the response pattern is itself non-stationary, as in the transient phase, a temperature program also becomes infeasible. We consider the problem of determining and tuning into a fixed optimum temperature in a sensor array. For this purpose, we present an empirical analysis of the temperature's role on the performance of a metal-oxide gas sensor array in the identification of odorants along the response transient. We show that the optimal temperature in this sense depends heavily on the selection of (i) the set of candidate analytes, (ii) the time-window of the analysis, (iii) the feature extracted from the sensor response, and (iv) the computational identification method used.

  20. Growth impairment due to transient hypercortisolism.

    PubMed

    Armour, K; Chalew, S; Kowarski, A A

    1986-01-01

    Cushing's syndrome in childhood is generally recognized by classical features such as truncal obesity, striae, easy bruising, moon facies, hypertension and growth retardation. Exceptionally, Cushing's syndrome has been reported to present as growth failure alone. We diagnosed transient hypercortisolism in 6 children who had poor growth as their only presenting abnormality. The 6 children all had integrated concentrations of cortisols (IC-F) (14.1 +/- 1.7 micrograms/dl; mean +/- 1 SD) which exceeded the IC-F in healthy children and adults (5.7 +/- 1.5 micrograms/dl; P less than 0.001). The IC-F of these 6 index cases overlapped the range of IC-F in patients with pathologically proven Cushing's syndrome (20.2 +/- 4.7 micrograms/dl). Four of the 6 patients were treated with human growth hormone for 8 months and showed a marked improvement in their growth rates. Four patients have entered puberty and are growing at normal rates. Three of the 6 children had normal repeat IC-Fs, subsequently, at a time they had normal growth rates. In 1-1/2 to 3 years of follow-up, none of the patients developed any other stigmata of Cushing's syndrome. We conclude that transient hypercortisolism, documented by the IC-F, may cause growth failure without other symptoms of Cushing's syndrome. Growth hormone therapy may improve the growth rate of these children at the time of their poor growth.

  1. Transient Spectra in TDDFT: Corrections and Correlations

    NASA Astrophysics Data System (ADS)

    Parkhill, John; Nguyen, Triet

    We introduce an atomistic, all-electron, black-box electronic structure code to simulate transient absorption (TA) spectra and apply it to simulate pyrazole and a GFP chromophore derivative. The method is an application of OSCF2, our dissipative extension of time-dependent density functional theory. We compare our simulated spectra directly with recent ultra-fast spectroscopic experiments, showing that they are usefully predicted. We also relate bleaches in the TA signal to Fermi-blocking which would be missed in a simplified model. An important ingredient in the method is the stationary-TDDFT correction scheme recently put forwards by Fischer, Govind, and Cramer which allows us to overcome a limitation of adiabatic TDDFT. We demonstrate that OSCF2 is able to predict both the energies of bleaches and induced absorptions, as well as the decay of the transient spectrum, with only the molecular structure as input. With remaining time we will discuss corrections which resolve the non-resonant behavior of driven TDDFT, and correlated corrections to mean-field dynamics.

  2. Enhancing photocurrent transient spectroscopy by electromagnetic modeling.

    PubMed

    Diesinger, H; Panahandeh-Fard, M; Wang, Z; Baillargeat, D; Soci, C

    2012-05-01

    The shape and duration of photocurrent transients generated by a photoconductive switch depend on both the intrinsic response of the active material and the geometry of the transmission line structure. The present electromagnetic model decouples both shape forming contributions. In contrast to previously published work, it accounts for the particular operating mode of transient spectroscopy. The objective is to increase the time resolution by two approaches, by optimizing structural response and by deconvolving it from experimental data. The switch structure is represented by an effective transimpedance onto which the active material acts as current generator. As proof of concept, the response of a standard microstrip switch is modeled and deconvolved from experimental data acquired in GaAs, yielding a single exponential material response and hence supporting the validity of the approach. Beyond compensating for the response deterioration by the structure, switch architectures can be a priori optimized with respect to frequency response. As an example, it is shown that a microstrip gap that can be deposited on materials incompatible with standard lithography reduces pulse broadening by an order of magnitude if it is provided with transitions to coplanar access lines.

  3. CUTIE: Cubesat Ultraviolet Transient Imaging Experiment

    NASA Astrophysics Data System (ADS)

    Cenko, Stephen B.; Bellm, Eric Christopher; Gal-Yam, Avishay; Gezari, Suvi; Gorjian, Varoujan; Jewell, April; Kruk, Jeffrey W.; Kulkarni, Shrinivas R.; Mushotzky, Richard; Nikzad, Shouleh; Piro, Anthony; Waxman, Eli; Ofek, Eran Oded

    2017-01-01

    We describe a mission concept for the Cubesat Ultraviolet Transient Imaging Experiment (CUTIE). CUTIE will image an area on the sky of ~ 1700 square degrees every ~ 95 min at near-UV wavelengths (260-320 nm) to a depth of 19.0 mag (AB). These capabilities represent orders of magnitude improvement over past UV imagers, allowing CUTIE to conduct the first true synoptic survey of the transient and variable sky in the UV bandpass. CUTIE will uniquely address key Decadal Survey science questions such as how massive stars end their lives, how super-massive black holes accrete material and influence their surroundings, and how suitable habitable-zone planets around low-mass stars are for hosting life. By partnering with upcoming ground-based time-domain surveys, CUTIE will further leverage its low-Earth orbit to provide a multi-wavelength view of the dynamic universe that can only be achieved from space. The remarkable sensitivity for such a small payload is achieved via the use of large format delta-doped CCDs; space qualifying this technology will serve as a key milestone towards the development of future large missions (Explorers and Surveyors). Finally, our innovative design in a 6U cubesat form factor will enable significant cost savings, accelerating the timeline from conception to on-sky operation (5 years; well matched for graduate student participation).

  4. Transient inter-cellular polymeric linker.

    PubMed

    Ong, Siew-Min; He, Lijuan; Thuy Linh, Nguyen Thi; Tee, Yee-Han; Arooz, Talha; Tang, Guping; Tan, Choon-Hong; Yu, Hanry

    2007-09-01

    Three-dimensional (3D) tissue-engineered constructs with bio-mimicry cell-cell and cell-matrix interactions are useful in regenerative medicine. In cell-dense and matrix-poor tissues of the internal organs, cells support one another via cell-cell interactions, supplemented by small amount of the extra-cellular matrices (ECM) secreted by the cells. Here we connect HepG2 cells directly but transiently with inter-cellular polymeric linker to facilitate cell-cell interaction and aggregation. The linker consists of a non-toxic low molecular-weight polyethyleneimine (PEI) backbone conjugated with multiple hydrazide groups that can aggregate cells within 30 min by reacting with the aldehyde handles on the chemically modified cell-surface glycoproteins. The cells in the cellular aggregates proliferated; and maintained the cortical actin distribution of the 3D cell morphology while non-aggregated cells died over 7 days of suspension culture. The aggregates lost distinguishable cell-cell boundaries within 3 days; and the ECM fibers became visible around cells from day 3 onwards while the inter-cellular polymeric linker disappeared from the cell surfaces over time. The transient inter-cellular polymeric linker can be useful for forming 3D cellular and tissue constructs without bulk biomaterials or extensive network of engineered ECM for various applications.

  5. Improving arrival time identification in transient elastography

    NASA Astrophysics Data System (ADS)

    Klein, Jens; McLaughlin, Joyce; Renzi, Daniel

    2012-04-01

    In this paper, we improve the first step in the arrival time algorithm used for shear wave speed recovery in transient elastography. In transient elastography, a shear wave is initiated at the boundary and the interior displacement of the propagating shear wave is imaged with an ultrasound ultra-fast imaging system. The first step in the arrival time algorithm finds the arrival times of the shear wave by cross correlating displacement time traces (the time history of the displacement at a single point) with a reference time trace located near the shear wave source. The second step finds the shear wave speed from the arrival times. In performing the first step, we observe that the wave pulse decorrelates as it travels through the medium, which leads to inaccurate estimates of the arrival times and ultimately to blurring and artifacts in the shear wave speed image. In particular, wave ‘spreading’ accounts for much of this decorrelation. Here we remove most of the decorrelation by allowing the reference wave pulse to spread during the cross correlation. This dramatically improves the images obtained from arrival time identification. We illustrate the improvement of this method on phantom and in vivo data obtained from the laboratory of Mathias Fink at ESPCI, Paris.

  6. Radio transients from newborn black holes

    NASA Astrophysics Data System (ADS)

    Kashiyama, Kazumi; Hotokezaka, Kenta; Murase, Kohta

    2018-05-01

    We consider radio emission from a newborn black hole (BH), which is accompanied by a mini-disk with a mass of ≲ M⊙. Such a disk can be formed from an outer edge of the progenitor's envelope, especially for metal-poor massive stars and/or massive stars in close binaries. The disk accretion rate is typically super-Eddington and an ultrafast outflow with a velocity of ˜0.1-0.3 c will be launched into the circumstellar medium. The outflow forms a collisionless shock, and electrons are accelerated and emit synchrotron emission in radio bands with a flux of ˜ 10^{26-30} erg s^{-1} Hz^{-1} days to decades after the BH formation. The model predicts not only a fast UV/optical transient but also quasi-simultaneous inverse-Compton X-ray emission ˜ a few days after the BH formation, and the discovery of the radio counterpart with coordinated searches will enable us to identify this type of transients. The occurrence rate can be 0.1 - 10 % of the core-collapse supernova rate, which makes them a promising target of dedicated radio observations such as the Jansky VLA Sky Survey.

  7. Detecting Thermal Cloaks via Transient Effects

    PubMed Central

    Sklan, Sophia R.; Bai, Xue; Li, Baowen; Zhang, Xiang

    2016-01-01

    Recent research on the development of a thermal cloak has concentrated on engineering an inhomogeneous thermal conductivity and an approximate, homogeneous volumetric heat capacity. While the perfect cloak of inhomogeneous κ and inhomogeneous ρcp is known to be exact (no signals scattering and only mean values penetrating to the cloak’s interior), the sensitivity of diffusive cloaks to defects and approximations has not been analyzed. We analytically demonstrate that these approximate cloaks are detectable. Although they work as perfect cloaks in the steady-state, their transient (time-dependent) response is imperfect and a small amount of heat is scattered. This is sufficient to determine the presence of a cloak and any heat source it contains, but the material composition hidden within the cloak is not detectable in practice. To demonstrate the feasibility of this technique, we constructed a cloak with similar approximation and directly detected its presence using these transient temperature deviations outside the cloak. Due to limitations in the range of experimentally accessible volumetric specific heats, our detection scheme should allow us to find any realizable cloak, assuming a sufficiently large temperature difference. PMID:27605153

  8. Neutronics and Transient Calculations for the Conversion of the Transient Reactor Rest Facility (TREAT)

    SciT

    Kontogeorgakos, Dimitrios C.; Connaway, Heather M.; Papadias, Dionissios D.

    2015-01-01

    The Transient Reactor Test Facility (TREAT) is a graphite-reflected, graphitemoderated, and air-cooled reactor fueled with 93.1% enriched UO2 particles dispersed in graphite, with a carbon-to-235U ratio of ~10000:1. TREAT was used to simulate accident conditions by subjecting fuel test samples placed at the center of the core to high energy transient pulses. The transient pulse production is based on the core’s selflimiting nature due to the negative reactivity feedback provided by the fuel graphite as the core temperature rises. The analysis of the conversion of TREAT to low enriched uranium (LEU) is currently underway. This paper presents the analytical methodsmore » used to calculate the transient performance of TREAT in terms of power pulse production and resulting peak core temperatures. The validation of the HEU neutronics TREAT model, the calculation of the temperature distribution and the temperature reactivity feedback as well as the number of fissions generated inside fuel test samples are discussed.« less

  9. Kinetically Controlled Lifetimes in Redox-Responsive Transient Supramolecular Hydrogels.

    PubMed

    Wojciechowski, Jonathan P; Martin, Adam D; Thordarson, Pall

    2018-02-28

    It remains challenging to program soft materials to show dynamic, tunable time-dependent properties. In this work, we report a strategy to design transient supramolecular hydrogels based on kinetic control of competing reactions. Specifically, the pH-triggered self-assembly of a redox-active supramolecular gelator, N,N'-dibenzoyl-l-cystine (DBC) in the presence of a reducing agent, which acts to disassemble the system. The lifetimes of the transient hydrogels can be tuned simply by pH or reducing agent concentration. We find through kinetic analysis that gel formation hinders the ability of the reducing agent and enables longer transient hydrogel lifetimes than would be predicted. The transient hydrogels undergo clean cycles, with no kinetically trapped aggregates observed. As a result, multiple transient hydrogel cycles are demonstrated and can be predicted. This work contributes to our understanding of designing transient assemblies with tunable temporal control.

  10. Integrated transient thermal-structural finite element analysis

    NASA Technical Reports Server (NTRS)

    Thornton, E. A.; Dechaumphai, P.; Wieting, A. R.; Tamma, K. K.

    1981-01-01

    An integrated thermal structural finite element approach for efficient coupling of transient thermal and structural analysis is presented. Integrated thermal structural rod and one dimensional axisymmetric elements considering conduction and convection are developed and used in transient thermal structural applications. The improved accuracy of the integrated approach is illustrated by comparisons with exact transient heat conduction elasticity solutions and conventional finite element thermal finite element structural analyses.

  11. Highlights of Transient Plume Impingement Model Validation and Applications

    NASA Technical Reports Server (NTRS)

    Woronowicz, Michael

    2011-01-01

    This paper describes highlights of an ongoing validation effort conducted to assess the viability of applying a set of analytic point source transient free molecule equations to model behavior ranging from molecular effusion to rocket plumes. The validation effort includes encouraging comparisons to both steady and transient studies involving experimental data and direct simulation Monte Carlo results. Finally, this model is applied to describe features of two exotic transient scenarios involving NASA Goddard Space Flight Center satellite programs.

  12. Laser-induced transient grating setup with continuously tunable period

    SciT

    Vega-Flick, A.; Applied Physics Department, CINVESTAV-Unidad Mérida, Carretera Antigua a Progreso Km 6, Cordemex, Mérida, Yucatán 97310 Mexico; Eliason, J. K.

    2015-12-15

    We present a modification of the laser-induced transient grating setup enabling continuous tuning of the transient grating period. The fine control of the period is accomplished by varying the angle of the diffraction grating used to split excitation and probe beams. The setup has been tested by measuring dispersion of bulk and surface acoustic waves in both transmission and reflection geometries. The presented modification is fully compatible with optical heterodyne detection and can be easily implemented in any transient grating setup.

  13. EBR-II high-ramp transients under computer control

    SciT

    Forrester, R.J.; Larson, H.A.; Christensen, L.J.

    1983-01-01

    During reactor run 122, EBR-II was subjected to 13 computer-controlled overpower transients at ramps of 4 MWt/s to qualify the facility and fuel for transient testing of LMFBR oxide fuels as part of the EBR-II operational-reliability-testing (ORT) program. A computer-controlled automatic control-rod drive system (ACRDS), designed by EBR-II personnel, permitted automatic control on demand power during the transients.

  14. Revealing transient strain in geodetic data with Gaussian process regression

    NASA Astrophysics Data System (ADS)

    Hines, T. T.; Hetland, E. A.

    2018-03-01

    Transient strain derived from global navigation satellite system (GNSS) data can be used to detect and understand geophysical processes such as slow slip events and post-seismic deformation. Here we propose using Gaussian process regression (GPR) as a tool for estimating transient strain from GNSS data. GPR is a non-parametric, Bayesian method for interpolating scattered data. In our approach, we assume a stochastic prior model for transient displacements. The prior describes how much we expect transient displacements to covary spatially and temporally. A posterior estimate of transient strain is obtained by differentiating the posterior transient displacements, which are formed by conditioning the prior with the GNSS data. As a demonstration, we use GPR to detect transient strain resulting from slow slip events in the Pacific Northwest. Maximum likelihood methods are used to constrain a prior model for transient displacements in this region. The temporal covariance of our prior model is described by a compact Wendland covariance function, which significantly reduces the computational burden that can be associated with GPR. Our results reveal the spatial and temporal evolution of strain from slow slip events. We verify that the transient strain estimated with GPR is in fact geophysical signal by comparing it to the seismic tremor that is associated with Pacific Northwest slow slip events.

  15. Transient Phenomena in Multiphase and Multicomponent Systems: Research Report

    NASA Astrophysics Data System (ADS)

    Zur Beurteilung von Stoffen in der Landwirtschaft, Senatskommission

    2000-09-01

    Due to the reinforced risk and safety-analysis of industrial plants in chemical and energy-engineering there has been increased demand in industry for more information on thermo- and fluiddynamic effects of non-equilibria during strong transients. Therefore, the 'Deutsche Forschungsgemeinschaft' initiated a special research program focusing on the study of transient phenomena in multiphase systems with one or several components. This book describes macroscopic as well as microscopic transient situations. A large part of the book deals with numerical methods for describing transients in two-phase mixtures. New developments in measuring techniques are also presented.

  16. Transients in the synchronization of asymmetrically coupled oscillator arrays

    NASA Astrophysics Data System (ADS)

    Cantos, C. E.; Hammond, D. K.; Veerman, J. J. P.

    2016-09-01

    We consider the transient behavior of a large linear array of coupled linear damped harmonic oscillators following perturbation of a single element. Our work is motivated by modeling the behavior of flocks of autonomous vehicles. We first state a number of conjectures that allow us to derive an explicit characterization of the transients, within a certain parameter regime Ω. As corollaries we show that minimizing the transients requires considering non-symmetric coupling, and that within Ω the computed linear growth in N of the transients is independent of (reasonable) boundary conditions.

  17. The Swift Burst and Transient Telescope (BAT)

    NASA Technical Reports Server (NTRS)

    Mushotzky, Richard

    2008-01-01

    The Swift Burst and Transient telescope (BAT) has surveyed the entire sky for the last 3.5 years obtaining the first sensitive all sky survey of the 14-195 kev sky. At high galactic latitudes the vast majority of the detected sources are AGN. Since hard x-rays penetrate all but Compton thick obscuring material (Column densities of 1.6324 atms/sq cm) this survey is unbiased with respect to obscuration, host galaxy type, optical , radio or IR properties. We will present results on the broad band x-ray properties, the nature of the host galaxies, the luminosity function and will discuss a few of the optical, IR and x-ray results in detail.

  18. TRUMP. Transient & S-State Temperature Distribution

    SciT

    Elrod, D.C.; Turner, W.D.

    1992-03-03

    TRUMP solves a general nonlinear parabolic partial differential equation describing flow in various kinds of potential fields, such as fields of temperature, pressure, or electricity and magnetism; simultaneously, it will solve two additional equations representing, in thermal problems, heat production by decomposition of two reactants having rate constants with a general Arrhenius temperature dependence. Steady-state and transient flow in one, two, or three dimensions are considered in geometrical configurations having simple or complex shapes and structures. Problem parameters may vary with spatial position, time, or primary dependent variables, temperature, pressure, or field strength. Initial conditions may vary with spatial position,more » and among the criteria that may be specified for ending a problem are upper and lower limits on the size of the primary dependent variable, upper limits on the problem time or on the number of time-steps or on the computer time, and attainment of steady state.« less

  19. Ignition transient analysis of solid rocket motor

    NASA Technical Reports Server (NTRS)

    Han, Samuel S.

    1990-01-01

    To predict pressure-time and thrust-time behavior of solid rocket motors, a one-dimensional numerical model is developed. The ignition phase of solid rocket motors (time less than 0.4 sec) depends critically on complex interactions among many elements, such as rocket geometry, heat and mass transfer, flow development, and chemical reactions. The present model solves the mass, momentum, and energy equations governing the transfer processes in the rocket chamber as well as the attached converging-diverging nozzle. A qualitative agreement with the SRM test data in terms of head-end pressure gradient and the total thrust build-up is obtained. Numerical results show that the burning rate in the star-segmented head-end section and the erosive burning are two important parameters in the ignition transient of the solid rocket motor (SRM).

  20. Transient response of a laminated composite plate

    NASA Technical Reports Server (NTRS)

    Datta, S. K.; Ju, T. H.; Bratton, R. L.; Shah, A. H.

    1992-01-01

    Results are presented from an investigation of the effect of layering on transient wave propagation in a laminated cross-ply plate, giving attention to the case of 2D plane strain in the case where a line vertical force is applied on a free surface of the plate; the line may be either parallel or perpendicular to the fibers in a ply. The results are in both the time and frequency domains for the normal stress component in the x direction, at a point on the surface of the plate on which the force is applied. Comparative results are also presented for a homogeneous plate whose properties are the static effective ones, when the number of plies is large.

  1. A Catalog of Coronal "EIT Wave" Transients

    NASA Technical Reports Server (NTRS)

    Thompson, B. J.; Myers, D. C.

    2005-01-01

    SOHO Extreme Ultraviolet Imaging Telescope (EIT) data have been visually searched for coronal "EIT wave" transients over the period beginning 24 March 1997 extending through 24 June 1998. The dates covered start at the beginning of regular high-cadence (more than 1 image every 20 minutes) observations, ending at the 4-month interruption of SOHO observations in mid-1998. 176 events are included in this catalog. The observations range from "candidate" events, which were either weak or had insufficient data coverage, to events which were well-defined and were clearly distinguishable in the data. Included in the catalog are times of the EIT images in which the events are observed, diagrams indicating the observed locations of the wavefronts and associated active regions, and the speeds of the wavefronts. The measured speeds of the wavefronts varied from less than 50 to over 700 km/sec with "typical" speeds of 200-400 Msec.

  2. Monitoring transients in low inductance circuits

    DOEpatents

    Guilford, Richard P.; Rosborough, John R.

    1987-01-01

    A pair of flat cable transmission lines are monitored for transient current spikes by using a probe connected to a current transformer by a pickup loop and monitoring the output of the current transformer. The approach utilizes a U-shaped pickup probe wherein the pair of flat cable transmission lines are received between the legs of the U-shaped probe. The U-shaped probe is preferably formed of a flat coil conductor adhered to one side of a flexible substrate. On the other side of the flexible substrate there is a copper foil shield. The copper foil shield is connected to one end of the flat conductor coil and connected to one leg of the pickup loop which passes through the current transformer. The other end of the flat conductor coil is connected to the other leg of the pickup loop.

  3. Robust optimization with transiently chaotic dynamical systems

    NASA Astrophysics Data System (ADS)

    Sumi, R.; Molnár, B.; Ercsey-Ravasz, M.

    2014-05-01

    Efficiently solving hard optimization problems has been a strong motivation for progress in analog computing. In a recent study we presented a continuous-time dynamical system for solving the NP-complete Boolean satisfiability (SAT) problem, with a one-to-one correspondence between its stable attractors and the SAT solutions. While physical implementations could offer great efficiency, the transiently chaotic dynamics raises the question of operability in the presence of noise, unavoidable on analog devices. Here we show that the probability of finding solutions is robust to noise intensities well above those present on real hardware. We also developed a cellular neural network model realizable with analog circuits, which tolerates even larger noise intensities. These methods represent an opportunity for robust and efficient physical implementations.

  4. Transient Analysis of a Magnetic Heat Pump

    NASA Technical Reports Server (NTRS)

    Schroeder, E. A.

    1985-01-01

    An experimental heat pump that uses a rare earth element as the refrigerant is modeled using NASTRAN. The refrigerant is a ferromagnetic metal whose temperature rises when a magnetic field is applied and falls when the magnetic field is removed. The heat pump is used as a refrigerator to remove heat from a reservoir and discharge it through a heat exchanger. In the NASTRAN model the components modeled are represented by one-dimensional ROD elements. Heat flow in the solids and fluid are analyzed. The problem is mildly nonlinear since the heat capacity of the refrigerant is temperature-dependent. One simulation run consists of a series of transient analyses, each representing one stroke of the heat pump. An auxiliary program was written that uses the results of one NASTRAN analysis to generate data for the next NASTRAN analysis.

  5. Faults Get Colder Through Transient Granular Vortices

    NASA Astrophysics Data System (ADS)

    Einav, I.; Rognon, P.; Miller, T.; Sulem, J.

    2018-03-01

    Fault temperatures govern their weakening and control the dynamics of earthquakes during slip. Despite predictions of significant temperature rise within fault gouges during earthquake events, observations of frictional melting zones along exhumed faults are relatively rare. Could there be a heat transfer mechanism, previously not considered, that results in ubiquitously colder faults during earthquakes? We demonstrate that the remarkable, previously neglected mechanism of heat transfer through transient granular vortices may be at the core of this. We present and analyze results from perpetual simple shear experiments on a system of granular disks with which we are able to quantify the sizes and lifetimes of granular vortices within fault gouges during earthquakes. We then develop a formula that captures the contribution these vortices have on heat transfer. Using this formula, we show that crustal faults such as those in the San Andreas system may experience a maximum temperature rise 5 to 10 times lower than previously thought.

  6. Transient electrohydrodynamics of a liquid drop.

    PubMed

    Esmaeeli, Asghar; Sharifi, Payam

    2011-09-01

    The transient behavior of a leaky dielectric liquid drop under a uniform electric field of small strength is investigated. It is shown that for small distortion from a spherical shape, the drop deforms to an ellipsoid, and the deformation time history is represented by D=D(∞)[1-exp(-t/τ)], where D(∞) is the steady-state deformation and τ=(aμ(o)/γ)(19μ+16)(2μ+3)/(40μ+40)is the characteristic time, a, γ, μ(o) and μ being the drop radius, the surface tension, the viscosity of ambient fluid, and ratio of the drop viscosity to that of the ambient fluid, respectively. The contributions of the net normal and tangential electrical stresses in the degree of deformation and fluid flow strength are also determined.

  7. A magnetohydrodynamic theory of coronal loop transients

    NASA Technical Reports Server (NTRS)

    Yeh, T.

    1982-01-01

    The physical and geometrical characteristics of solar coronal loop transients are described in an MHD model based on Archimedes' MHD buoyancy force. The theory was developed from interpretation of coronagraphic data, particularly from Skylab. The brightness of a loop is taken to indicate the electron density, and successive pictures reveal the electron enhancement in different columns. The forces which lift the loop off the sun surface are analyzed as an MHD buoyancy force affecting every mass element by imparting an inertial force necessary for heliocentrifugal motion. Thermal forces are responsible for transferring the ambient stress to the interior of the loop to begin the process. The kinematic and hydrostatic buoyancy overcome the gravitational force, and a flux rope can then curve upward, spiralling like a corkscrew with varying cross section around the unwinding solar magnetic field lines.

  8. Modeling of transient heat pipe operation

    NASA Technical Reports Server (NTRS)

    Colwell, Gene T.

    1987-01-01

    The use of heat pipes is being considered as a means of reducing the peak temperature and large thermal gradients at the leading edges of reentry vehicles and hypersonic aircraft and in nuclear reactors. In the basic cooling concept, the heat pipe covers the leading edge, a portion of the lower wing surface, and a portion of the upper wing surface. Aerodynamic heat is mainly absorbed at the leading edge and transported through the heat pipe to the upper and lower wing surface, where it is rejected by thermal radiation and convection. Basic governing equations are written to determine the startup, transient, and steady state performance of a haet pipe which has initially frozen alkali-metal as the working fluid.

  9. On coincident loop transient electromagnetic induction logging

    SciT

    Swidinsky, Andrei; Weiss, Chester J.

    Coincident loop transient induction wireline logging is examined as the borehole analog of the well-known land and airborne time-domain electromagnetic (EM) method. The concept of whole-space late-time apparent resistivity is modified from the half-space version commonly used in land and airborne geophysics and applied to the coincident loop voltages produced from various formation, borehole, and invasion models. Given typical tool diameters, off-time measurements with such an instrument must be made on the order of nanoseconds to microseconds — much more rapidly than for surface methods. Departure curves of the apparent resistivity for thin beds, calculated using an algorithm developed tomore » model the transient response of a loop in a multilayered earth, indicate that the depth of investigation scales with the bed thickness. Modeled resistivity logs are comparable in accuracy and resolution with standard frequency-domain focused induction logs. However, if measurement times are longer than a few microseconds, the thicknesses of conductors can be overestimated, whereas resistors are underestimated. Thin-bed resolution characteristics are explained by visualizing snapshots of the EM fields in the formation, where a conductor traps the electric field while two current maxima are produced in the shoulder beds surrounding a resistor. Radial profiling is studied using a concentric cylinder earth model. Results found that true formation resistivity can be determined in the presence of either oil- or water-based mud, although in the latter case, measurements must be taken several orders of magnitude later in time. Lastly, the ability to determine true formation resistivity is governed by the degree that the EM field heals after being distorted by borehole fluid and invasion, a process visualized and particularly evident in the case of conductive water-based mud.« less

  10. On coincident loop transient electromagnetic induction logging

    DOE PAGES

    Swidinsky, Andrei; Weiss, Chester J.

    2017-05-31

    Coincident loop transient induction wireline logging is examined as the borehole analog of the well-known land and airborne time-domain electromagnetic (EM) method. The concept of whole-space late-time apparent resistivity is modified from the half-space version commonly used in land and airborne geophysics and applied to the coincident loop voltages produced from various formation, borehole, and invasion models. Given typical tool diameters, off-time measurements with such an instrument must be made on the order of nanoseconds to microseconds — much more rapidly than for surface methods. Departure curves of the apparent resistivity for thin beds, calculated using an algorithm developed tomore » model the transient response of a loop in a multilayered earth, indicate that the depth of investigation scales with the bed thickness. Modeled resistivity logs are comparable in accuracy and resolution with standard frequency-domain focused induction logs. However, if measurement times are longer than a few microseconds, the thicknesses of conductors can be overestimated, whereas resistors are underestimated. Thin-bed resolution characteristics are explained by visualizing snapshots of the EM fields in the formation, where a conductor traps the electric field while two current maxima are produced in the shoulder beds surrounding a resistor. Radial profiling is studied using a concentric cylinder earth model. Results found that true formation resistivity can be determined in the presence of either oil- or water-based mud, although in the latter case, measurements must be taken several orders of magnitude later in time. Lastly, the ability to determine true formation resistivity is governed by the degree that the EM field heals after being distorted by borehole fluid and invasion, a process visualized and particularly evident in the case of conductive water-based mud.« less

  11. Response of hyporheic zones to transient forcing

    NASA Astrophysics Data System (ADS)

    Singh, T.; Wu, L.; Gomez-Velez, J. D.; Krause, S.; Hannah, D. M.; Lewandowski, J.; Nuetzmann, G.

    2017-12-01

    Exchange of water, solutes, and energy between river channels and hyporheic zones (HZs) modulates biogeochemical cycling, regulates stream temperature and impacts ecological structure and function. Numerical modelling of HZ processes is required as field observations are challenging for transient flow. To gain a deeper mechanistic understanding of the effects of transient discharge on hyporheic exchange, we performed a systematic analysis using numerical experiments. In this case, we vary (i) the characteristics of time-varying flood events; (ii) river bedform geometry; (iii) river hydraulic geometry; and (iv) the magnitude and direction of groundwater fluxes (neutral, gaining and losing conditions). We conceptualize the stream bed as a two-dimensional system. Whereby the flow is driven by a dynamically changing head distribution at the water-sediment interface and is modulated by steady groundwater flow. Our model estimates both net values for a single bedform and spatial distributions of (i) the flow field; (ii) mean residence times; and (iii) the concentration of a conservative tracer. A detailed sensitivity analysis was performed by changing channel slope, flood characteristics, groundwater upwelling/downwelling fluxes and biogeochemical time-scales in different bedforms such as ripples, dunes and alternating bars. Results show that change of parameters can have a substantial impact on exchange fluxes which can lead to the expansion, contraction, emergence and/or dissipation of HZs . Our results also reveal that groundwater fluxes have different impacts on HZs during flood events, depending on the channel slope and bedform topography. It is found that topographies with smaller aspect ratios and shallower slopes are more affected by groundwater upwelling/downwelling fluxes during flood events. The analysis of biogeochemical transformations shows that discharge events can potentially affects the efficiencies of nitrate removal. Taking into consideration multiple

  12. Robust Transient Dynamics and Brain Functions

    PubMed Central

    Rabinovich, Mikhail I.; Varona, Pablo

    2011-01-01

    In the last few decades several concepts of dynamical systems theory (DST) have guided psychologists, cognitive scientists, and neuroscientists to rethink about sensory motor behavior and embodied cognition. A critical step in the progress of DST application to the brain (supported by modern methods of brain imaging and multi-electrode recording techniques) has been the transfer of its initial success in motor behavior to mental function, i.e., perception, emotion, and cognition. Open questions from research in genetics, ecology, brain sciences, etc., have changed DST itself and lead to the discovery of a new dynamical phenomenon, i.e., reproducible and robust transients that are at the same time sensitive to informational signals. The goal of this review is to describe a new mathematical framework – heteroclinic sequential dynamics – to understand self-organized activity in the brain that can explain certain aspects of robust itinerant behavior. Specifically, we discuss a hierarchy of coarse-grain models of mental dynamics in the form of kinetic equations of modes. These modes compete for resources at three levels: (i) within the same modality, (ii) among different modalities from the same family (like perception), and (iii) among modalities from different families (like emotion and cognition). The analysis of the conditions for robustness, i.e., the structural stability of transient (sequential) dynamics, give us the possibility to explain phenomena like the finite capacity of our sequential working memory – a vital cognitive function –, and to find specific dynamical signatures – different kinds of instabilities – of several brain functions and mental diseases. PMID:21716642

  13. Sleep modifications in acute transient global amnesia.

    PubMed

    Della Marca, Giacomo; Mazza, Marianna; Losurdo, Anna; Testani, Elisa; Broccolini, Aldobrando; Frisullo, Giovanni; Marano, Giuseppe; Morosetti, Roberta; Pilato, Fabio; Profice, Paolo; Vollono, Catello; Di Lazzaro, Vincenzo

    2013-09-15

    Transient global amnesia (TGA) is a temporary memory loss characterized by an abrupt onset of antero-grade and retrograde amnesia, totally reversible. Since sleep plays a major role in memory consolidation, and in the storage of memory-related traces into the brain cortex, the aims of the present study were: (1) to evaluate changes in sleep macro-structure in TGA; (2) to assess modifications in sleep micro-structure in TGA, with particular reference to the arousal EEG and to cyclic alternating pattern (CAP); (3) to compare sleep parameters in TGA patients with a control group of patients with acute ischemic events ("minor stroke" or transient ischemic attack [TIA]) clinically and neuroradiologically "similar" to the TGA. TGA GROUP: 17 patients, (8 men and 9 women, 60.2 ± 12.5 years). Stroke or TIA (SoT) group: 17 patients hospitalized in the Stroke Unit for recent onset of minor stroke or TIA with hemispheric localization; healthy controls (HC) group: 17 healthy volunteers, matched for age and sex. Patients and controls underwent full-night polysomnography. In the multivariate analysis (conditions TGA, SoT, and HC) a significant effect of the condition was observed for sleep efficiency index, number of awakenings longer 1 min, REM latency, CAP time, and CAP rate. TGA and SoT differed only for CAP time and CAP rate, which were lower in the TGA group. Microstructural modification associated with tga could be consequent to: (1) hippocampal dysfunction and memory impairment; (2) impairment of arousal-related structures (in particular, cholinergic pathways); (3) emotional distress.

  14. Harnessing quantum transport by transient chaos.

    PubMed

    Yang, Rui; Huang, Liang; Lai, Ying-Cheng; Grebogi, Celso; Pecora, Louis M

    2013-03-01

    Chaos has long been recognized to be generally advantageous from the perspective of control. In particular, the infinite number of unstable periodic orbits embedded in a chaotic set and the intrinsically sensitive dependence on initial conditions imply that a chaotic system can be controlled to a desirable state by using small perturbations. Investigation of chaos control, however, was largely limited to nonlinear dynamical systems in the classical realm. In this paper, we show that chaos may be used to modulate or harness quantum mechanical systems. To be concrete, we focus on quantum transport through nanostructures, a problem of considerable interest in nanoscience, where a key feature is conductance fluctuations. We articulate and demonstrate that chaos, more specifically transient chaos, can be effective in modulating the conductance-fluctuation patterns. Experimentally, this can be achieved by applying an external gate voltage in a device of suitable geometry to generate classically inaccessible potential barriers. Adjusting the gate voltage allows the characteristics of the dynamical invariant set responsible for transient chaos to be varied in a desirable manner which, in turn, can induce continuous changes in the statistical characteristics of the quantum conductance-fluctuation pattern. To understand the physical mechanism of our scheme, we develop a theory based on analyzing the spectrum of the generalized non-Hermitian Hamiltonian that includes the effect of leads, or electronic waveguides, as self-energy terms. As the escape rate of the underlying non-attracting chaotic set is increased, the imaginary part of the complex eigenenergy becomes increasingly large so that pointer states are more difficult to form, making smoother the conductance-fluctuation pattern.

  15. TRANSIENT LUNAR PHENOMENA: REGULARITY AND REALITY

    SciT

    Crotts, Arlin P. S.

    2009-05-20

    Transient lunar phenomena (TLPs) have been reported for centuries, but their nature is largely unsettled, and even their existence as a coherent phenomenon is controversial. Nonetheless, TLP data show regularities in the observations; a key question is whether this structure is imposed by processes tied to the lunar surface, or by terrestrial atmospheric or human observer effects. I interrogate an extensive catalog of TLPs to gauge how human factors determine the distribution of TLP reports. The sample is grouped according to variables which should produce differing results if determining factors involve humans, and not reflecting phenomena tied to the lunarmore » surface. Features dependent on human factors can then be excluded. Regardless of how the sample is split, the results are similar: {approx}50% of reports originate from near Aristarchus, {approx}16% from Plato, {approx}6% from recent, major impacts (Copernicus, Kepler, Tycho, and Aristarchus), plus several at Grimaldi. Mare Crisium produces a robust signal in some cases (however, Crisium is too large for a 'feature' as defined). TLP count consistency for these features indicates that {approx}80% of these may be real. Some commonly reported sites disappear from the robust averages, including Alphonsus, Ross D, and Gassendi. These reports begin almost exclusively after 1955, when TLPs became widely known and many more (and inexperienced) observers searched for TLPs. In a companion paper, we compare the spatial distribution of robust TLP sites to transient outgassing (seen by Apollo and Lunar Prospector instruments). To a high confidence, robust TLP sites and those of lunar outgassing correlate strongly, further arguing for the reality of TLPs.« less

  16. Review of Transient Testing of Fast Reactor Fuels in the Transient REActor Test Facility (TREAT)

    SciT

    Jensen, C.; Wachs, D.; Carmack, J.

    The restart of the Transient REActor Test (TREAT) facility provides a unique opportunity to engage the fast reactor fuels community to reinitiate in-pile experimental safety studies. Historically, the TREAT facility played a critical role in characterizing the behavior of both metal and oxide fast reactor fuels under off-normal conditions, irradiating hundreds of fuel pins to support fast reactor fuel development programs. The resulting test data has provided validation for a multitude of fuel performance and severe accident analysis computer codes. This paper will provide a review of the historical database of TREAT experiments including experiment design, instrumentation, test objectives, andmore » salient findings. Additionally, the paper will provide an introduction to the current and future experiment plans of the U.S. transient testing program at TREAT.« less

  17. Transient hypothyroidism after iodine-131 therapy for Grave's disease.

    PubMed

    Gómez, N; Gómez, J M; Orti, A; Gavaldà, L; Villabona, C; Leyes, P; Soler, J

    1995-09-01

    We studied 355 patients with Grave's disease to characterize transient hypothyroidism and its prognostic value following 131I therapy. The patients received therapeutic 131I treatment as follows: 333 received a dose < 10 mCi (6.6 +/- 1.9 mCi) and 22 received a dose > 10 mCi (12.8 +/- 2.9 mCi). Diagnosis of transient hypothyroidism was based on low T4, regardless of TSH within the first year after 131I followed by recovery of T4 and normal TSH. After administration of < 10 mCi 131I, 40 patients developed transient hypothyroidism during the first year; transient hypothyroidism was symptomatic in 15. There was no transient hypothyroidism after high doses (> 10 mCi) of 131I. Iodine-131 uptake > 70% at 2 hr before treatment was a risk factor for developing transient hypothyroidism (Odds ratio 2.8, 95% confidence interval 0.9-9.4). At diagnosis of transient hypothyroidism, basal TSH levels were high (51%), normal (35%) or low (14%); therefore, the transient hypothyroidism was not centralized. If hypothyroidism developed during the first 6 mo after basal TSH > 45 mU/liter ruled out transient hypothyroidism. The development of transient hypothyroidism and its hormonal pattern did not influence long-term thyroid function. Since no prognostic factors reliably predicted transient hypothyroidism before 131I or at the time of diagnosis, if hypothyroidism appears within the first months after 131I, the reevaluation of thyroid function later is warranted to avoid unnecessary chronic replacement therapy.

  18. Timing of transients: quantifying reaching times and transient behavior in complex systems

    NASA Astrophysics Data System (ADS)

    Kittel, Tim; Heitzig, Jobst; Webster, Kevin; Kurths, Jürgen

    2017-08-01

    In dynamical systems, one may ask how long it takes for a trajectory to reach the attractor, i.e. how long it spends in the transient phase. Although for a single trajectory the mathematically precise answer may be infinity, it still makes sense to compare different trajectories and quantify which of them approaches the attractor earlier. In this article, we categorize several problems of quantifying such transient times. To treat them, we propose two metrics, area under distance curve and regularized reaching time, that capture two complementary aspects of transient dynamics. The first, area under distance curve, is the distance of the trajectory to the attractor integrated over time. It measures which trajectories are ‘reluctant’, i.e. stay distant from the attractor for long, or ‘eager’ to approach it right away. Regularized reaching time, on the other hand, quantifies the additional time (positive or negative) that a trajectory starting at a chosen initial condition needs to approach the attractor as compared to some reference trajectory. A positive or negative value means that it approaches the attractor by this much ‘earlier’ or ‘later’ than the reference, respectively. We demonstrated their substantial potential for application with multiple paradigmatic examples uncovering new features.

  19. 17 CFR 270.3a-2 - Transient investment companies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Transient investment companies... (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.3a-2 Transient investment companies... which an issuer owns or proposes to acquire investment securities (as defined in section 3(a) of the Act...

  20. Measurement of Turbine Engine Transient Airflow in Ground Test Facilities

    DTIC Science & Technology

    1980-08-01

    REPORT NUMBER 12 GOVT ACCESSION NO. A E D C - T R - 8 0 - 2 1 L 6. T I T L E (aqd Subl l l |e ) MEASUREMENT OF TURBINE ENGINE TRANSIENT AIRFLOW IN...21 ILLUSTRATIONS Figure !. Direct-Connect Turbine Engine Test Cell Installation...26 3. Turbine Engine Transient Airflow Simulator (TETAS) . . . . . . . . . . . . . . . . . . . . . . . . . 27 4

  1. 17 CFR 270.3a-2 - Transient investment companies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Transient investment companies... (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.3a-2 Transient investment companies... which an issuer owns or proposes to acquire investment securities (as defined in section 3(a) of the Act...

  2. Transient flow thrust prediction for an ejector propulsion concept

    NASA Technical Reports Server (NTRS)

    Drummond, Colin K.

    1989-01-01

    A method for predicting transient thrust augmenting ejector characteristics is introduced. The analysis blends classic self-similar turbulent jet descriptions with a mixing region control volume analysis to predict transient effects in a new way. Details of the theoretical foundation, the solution algorithm, and sample calculations are given.

  3. Network Connectivity for Permanent, Transient, Independent, and Correlated Faults

    NASA Technical Reports Server (NTRS)

    White, Allan L.; Sicher, Courtney; henry, Courtney

    2012-01-01

    This paper develops a method for the quantitative analysis of network connectivity in the presence of both permanent and transient faults. Even though transient noise is considered a common occurrence in networks, a survey of the literature reveals an emphasis on permanent faults. Transient faults introduce a time element into the analysis of network reliability. With permanent faults it is sufficient to consider the faults that have accumulated by the end of the operating period. With transient faults the arrival and recovery time must be included. The number and location of faults in the system is a dynamic variable. Transient faults also introduce system recovery into the analysis. The goal is the quantitative assessment of network connectivity in the presence of both permanent and transient faults. The approach is to construct a global model that includes all classes of faults: permanent, transient, independent, and correlated. A theorem is derived about this model that give distributions for (1) the number of fault occurrences, (2) the type of fault occurrence, (3) the time of the fault occurrences, and (4) the location of the fault occurrence. These results are applied to compare and contrast the connectivity of different network architectures in the presence of permanent, transient, independent, and correlated faults. The examples below use a Monte Carlo simulation, but the theorem mentioned above could be used to guide fault-injections in a laboratory.

  4. Transient synchrony among populations of five foliage-feeding Lepidoptera

    Maartje J. Klapwijk; Jonathan A. Walter; Anikó Hirka; György Csóka; Christer Björkman; Andrew M. Liebhold

    2018-01-01

    Studies of transient population dynamics have largely focused on temporal changes in dynamical behaviour, such as the transition between periods of stability and instability. This study explores a related dynamic pattern, namely transient synchrony during a 49-year period among populations of five sympatric species of forest insects that share host tree resources. The...

  5. OGLE-IV Transient Search report 26 August 2016

    NASA Astrophysics Data System (ADS)

    Wyrzykowski, L.; Sitek, M.; Kostrzewa-Rutkowska, Z.; Udalski, A.; Kozlowski, S.; Klencki, J.

    2016-08-01

    The OGLE-IV Transient Detection System (Wyrzykowski et al. 2014, AcA,64,197; Kozlowski et al. 2013; Klencki et al. 2016, AcA, 66,15) announces resumption of operation in the beginning of 2016B season and discovery of 45 new on-going transients.

  6. OGLE-IV Transient Search report 07 August 2015

    NASA Astrophysics Data System (ADS)

    Wyrzykowski, L.; Kostrzewa-Rutkowska, Z.; Udalski, A.; Kozlowski, S.; Poleski, R.; Pietrzynski, G.; Sitek, M.

    2015-08-01

    The OGLE-IV Transient Detection System (Wyrzykowski et al. 2014, AcA,64,197; Kozlowski et al. 2013) reports the discovery of 10 new transients. Most of them appeared near or on top of apparent galaxies and their light curves resemble those of supernovae near or after their peak brightness.

  7. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Siebert, M. R.; Pan, Y.-C.; Kilpatrick, C. D.; Foley, R. J.

    2017-07-01

    We report the following classifications of optical transients from spectroscopic observations with KOSMOS on the KPNO Mayall 4-m telescope. Targets were supplied by the Asteroid Terrestrial-impact Last Alert System (ATLAS; ATel #8680), the Pan-STARRS Survey for Transients (PSST) and Gaia.

  8. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Pan, Y.-C.; Kilpatrick, C. D.; Siebert, M. R.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-08-01

    We report the following classifications of optical transients from spectroscopic observations with KOSMOS on the KPNO Mayall 4-m telescope. Targets were supplied by the Pan-STARRS Survey for Transients (PSST) and the All-Sky Automated Survey for Supernovae (ASAS-SN).

  9. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Pan, Y.-C.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-06-01

    We report the following classifications of optical transients from spectroscopic observations with KOSMOS on the KPNO Mayall 4-m telescope. Targets were supplied by the Pan-STARRS Survey for Transients (PSST), All-Sky Automated Survey for Supernovae (ASAS-SN) and MASTER.

  10. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Kilpatrick, C. D.; Pan, Y.-C.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2017-02-01

    We report the following classifications of optical transients from spectroscopic observations with KOSMOS on the KPNO Mayall 4-m telescope. Targets were supplied by the All-Sky Automated Survey for Supernovae (ASAS-SN), the ATLAS project (ATel #8680), and the Pan-STARRS Survey for Transients (PSST).

  11. Transient water stress in a vegetation canopy - Simulations and measurements

    NASA Technical Reports Server (NTRS)

    Carlson, Toby N.; Belles, James E.; Gillies, Robert R.

    1991-01-01

    Consideration is given to observational and modeling evidence of transient water stress, the effects of the transpiration plateau on the canopy radiometric temperature, and the factors responsible for the onset of the transpiration plateau, such as soil moisture. Attention is also given to the point at which the transient stress can be detected by remote measurement of surface temperature.

  12. Transient rheology of crystallizing andesitic magmas

    NASA Astrophysics Data System (ADS)

    de Biasi, L. J.; Chevrel, M. O.; Hanson, J. B.; Cimarelli, C.; Lavallée, Y.; Dingwell, D. B.

    2012-04-01

    The viscosity of magma strongly influences its rheological behaviour, which is a key determinant of magma transport processes and volcanic eruptions. Understanding the factors controlling the viscosity of magma is important to our assessment of hazards posed by active volcanoes. In nature, magmas span a very wide range in viscosity (10-1 to 1014 Pa s), depending on chemical composition (including volatile content), temperature, and importantly, crystal fraction, which further induces a complex strain rate dependence (i.e. non-Newtonian rheology). Here, we present results of transient viscosities of a crystallizing andesitic melt (57 wt.% SiO2) from Tungurahua volcano (Ecuador). We followed the experimental method developed by Vona et al. (2011) for the concentric cylinder apparatus, but optimized its implementation by leaving the spindle in situ before quenching the experimental products, to preserve the complete developed texture of the sample. The viscosity is investigated under super-liquidus (1400 ° C) and sub-liquidus temperatures (1162 and 1167 ° C). For each temperature increment, thermal equilibrium is achieved over a period of days while the spindle constantly stirs the magma. Simultaneous monitoring of the torque is used to calculate the apparent viscosity of the transient suspension. To get a better understanding of the nucleation and crystal growth processes that are involved at sub-liquidus conditions, further time-step experiments were carried out, where the samples were quenched at various equilibration stages. The mineralogical assemblage, as well as the crystal fraction, distribution and preferential alignment were then quantitatively analyzed. At temperatures below the liquidus, the suspension shows a progressive, but irregular increase of the relative shear viscosity. First, the viscosity slightly increases, possibly due to the crystallization of small, equant oxides and the formation of plagioclase nuclei. After some time (1.5-2.5 days

  13. Transient sodium current at subthreshold voltages: activation by EPSP waveforms

    PubMed Central

    Carter, Brett C.; Giessel, Andrew J.; Sabatini, Bernardo L.; Bean, Bruce P.

    2012-01-01

    Summary Tetrodotoxin (TTX)-sensitive sodium channels carry large transient currents during action potentials and also “persistent” sodium current, a non-inactivating TTX-sensitive current present at subthreshold voltages. We examined gating of subthreshold sodium current in dissociated cerebellar Purkinje neurons and hippocampal CA1 neurons, studied at 37 °C with near-physiological ionic conditions. Unexpectedly, in both cell types small voltage steps at subthreshold voltages activated a substantial component of transient sodium current as well as persistent current. Subthreshold EPSP-like waveforms also activated a large component of transient sodium current, but IPSP-like waveforms engaged primarily persistent sodium current with only a small additional transient component. Activation of transient as well as persistent sodium current at subthreshold voltages produces amplification of EPSPs that is sensitive to the rate of depolarization and can help account for the dependence of spike threshold on depolarization rate, as previously observed in vivo. PMID:22998875

  14. Transient-state kinetic approach to mechanisms of enzymatic catalysis.

    PubMed

    Fisher, Harvey F

    2005-03-01

    Transient-state kinetics by its inherent nature can potentially provide more directly observed detailed resolution of discrete events in the mechanistic time courses of enzyme-catalyzed reactions than its more widely used steady-state counterpart. The use of the transient-state approach, however, has been severely limited by the lack of any theoretically sound and applicable basis of interpreting the virtual cornucopia of time and signal-dependent phenomena that it provides. This Account describes the basic kinetic behavior of the transient state, critically examines some currently used analytic methods, discusses the application of a new and more soundly based "resolved component transient-state time-course method" to the L-glutamate-dehydrogenase reaction, and establishes new approaches for the analysis of both single- and multiple-step substituted transient-state kinetic isotope effects.

  15. Transient Point Infiltration In The Unsaturated Zone

    NASA Astrophysics Data System (ADS)

    Buecker-Gittel, M.; Mohrlok, U.

    The risk assessment of leaking sewer pipes gets more and more important due to urban groundwater management and environmental as well as health safety. This requires the quantification and balancing of transport and transformation processes based on the water flow in the unsaturated zone. The water flow from a single sewer leakage could be described as a point infiltration with time varying hydraulic conditions externally and internally. External variations are caused by the discharge in the sewer pipe as well as the state of the leakage itself. Internal variations are the results of microbiological clogging effects associated with the transformation processes. Technical as well as small scale laboratory experiments were conducted in order to investigate the water transport from an transient point infiltration. From the technical scale experiment there was evidence that the water flow takes place under transient conditions when sewage infiltrates into an unsaturated soil. Whereas the small scale experiments investigated the hydraulics of the water transport and the associated so- lute and particle transport in unsaturated soils in detail. The small scale experiment was a two-dimensional representation of such a point infiltration source where the distributed water transport could be measured by several tensiometers in the soil as well as by a selective measurement of the discharge at the bottom of the experimental setup. Several series of experiments were conducted varying the boundary and initial con- ditions in order to derive the important parameters controlling the infiltration of pure water from the point source. The results showed that there is a significant difference between the infiltration rate in the point source and the discharge rate at the bottom, that could be explained by storage processes due to an outflow resistance at the bottom. This effect is overlayn by a decreasing water content decreases over time correlated with a decreasing infiltration

  16. Outflow-driven Transients from the Birth of Binary Black Holes. II. Primary-induced Accretion Transients

    NASA Astrophysics Data System (ADS)

    Kimura, Shigeo S.; Murase, Kohta; Mészáros, Peter

    2017-12-01

    We discuss the electromagnetic radiation from newborn binary black holes (BBHs). As a consequence of the evolution of massive stellar binaries, a binary consisting of a primary black hole (BH) and a secondary Wolf–Rayet star is expected as a BBH progenitor system. We investigate optical transients from the birth of BBHs powered by the Bondi–Hoyle–Lyttleton accretion onto the primary BH, which occur ∼1–10 Gyr earlier than gravitational-wave signals at the BH–BH merger. When the secondary massive star collapses into a BH, it may eject a fraction of its outer material and may form a disk around the primary BH and induces a powerful disk wind. These primary-induced winds can lead to optical transients with a kinetic energy of ∼1047–3 × 1048 erg, an ejecta velocity of 108–109 cm s‑1, a duration of a few days, and an absolute magnitude ranging from about ‑11 to ‑14. The light curves and late-time spectra of these transients are distinctive from those of ordinary supernovae, and detection of this type of transient is possible by future optical transient surveys if the event rate of this transient is comparable to the merger rate of BBHs. This paper focuses on the emissions from disk-driven transients induced by the primary BH, different from Paper I, which focuses on wind-driven transients from the tidally locked secondary massive star.

  17. Transient quantum fluctuation theorems and generalized measurements

    NASA Astrophysics Data System (ADS)

    Prasanna Venkatesh, B.; Watanabe, Gentaro; Talkner, Peter

    2014-01-01

    The transient quantum fluctuation theorems of Crooks and Jarzynski restrict and relate the statistics of work performed in forward and backward forcing protocols. So far, these theorems have been obtained under the assumption that the work is determined by two projective energy measurements, one at the end, and the other one at the beginning of each run of the protocol. We found that one can replace these two projective measurements only by special error-free generalized energy measurements with pairs of tailored, protocol-dependent post-measurement states that satisfy detailed balance-like relations. For other generalized measurements, the Crooks relation is typically not satisfied. For the validity of the Jarzynski equality, it is sufficient that the first energy measurements are error-free and the post-measurement states form a complete orthonormal set of elements in the Hilbert space of the considered system. Additionally, the effects of the second energy measurements must have unit trace. We illustrate our results by an example of a two-level system for different generalized measurements.

  18. Transient quantum fluctuation theorems and generalized measurements

    NASA Astrophysics Data System (ADS)

    Prasanna Venkatesh, B.; Watanabe, Gentaro; Talkner, Peter

    2014-05-01

    The transient quantum fluctuation theorems of Crooks and Jarzynski restrict and relate the statistics of work performed in forward and backward forcing protocols. So far, these theorems have been obtained under the assumption that the work is determined by two projective energy measurements, one at the end, and the other one at the beginning of each run of the protocol.We found that one can replace these two projective measurements only by special error-free generalized energy measurements with pairs of tailored, protocol-dependent post-measurement states that satisfy detailed balance-like relations. For other generalized measurements, the Crooks relation is typically not satisfied. For the validity of the Jarzynski equality, it is sufficient that the first energy measurements are error-free and the post-measurement states form a complete orthonormal set of elements in the Hilbert space of the considered system. Additionally, the effects of the second energy measurements must have unit trace. We illustrate our results by an example of a two-level system for different generalized measurements.

  19. Viscoelastic Transient of Confined Red Blood Cells

    PubMed Central

    Prado, Gaël; Farutin, Alexander; Misbah, Chaouqi; Bureau, Lionel

    2015-01-01

    The unique ability of a red blood cell to flow through extremely small microcapillaries depends on the viscoelastic properties of its membrane. Here, we study in vitro the response time upon flow startup exhibited by red blood cells confined into microchannels. We show that the characteristic transient time depends on the imposed flow strength, and that such a dependence gives access to both the effective viscosity and the elastic modulus controlling the temporal response of red cells. A simple theoretical analysis of our experimental data, validated by numerical simulations, further allows us to compute an estimate for the two-dimensional membrane viscosity of red blood cells, ηmem2D ∼ 10−7 N⋅s⋅m−1. By comparing our results with those from previous studies, we discuss and clarify the origin of the discrepancies found in the literature regarding the determination of ηmem2D, and reconcile seemingly conflicting conclusions from previous works. PMID:25954871

  20. Transient and Sharvin resistances of Luttinger liquids

    NASA Astrophysics Data System (ADS)

    Kloss, Thomas; Weston, Joseph; Waintal, Xavier

    2018-04-01

    Although the intrinsic conductance of an interacting one-dimensional system is renormalized by the electron-electron correlations, it has been known for some time that this renormalization is washed out by the presence of the (noninteracting) electrodes to which the wire is connected. Here, we study the transient conductance of such a wire: a finite voltage bias is suddenly applied across the wire and we measure the current before it has enough time to reach its stationary value. These calculations allow us to extract the Sharvin (contact) resistance of Luttinger and Fermi liquids. In particular, we find that a perfect junction between a Fermi liquid electrode and a Luttinger liquid electrode is characterized by a contact resistance that consists of half the quantum of conductance in series with half the intrinsic resistance of an infinite Luttinger liquid. These results were obtained using two different methods: a dynamical Hartree-Fock approach and a self-consistent Boltzmann approach. Although these methods are formally approximate, we find a perfect match with the exact results of Luttinger/Fermi liquid theory.

  1. Transient translational quiescence in primordial germ cells

    PubMed Central

    Oulhen, Nathalie; Swartz, S. Zachary; Laird, Jessica; Mascaro, Alexandra

    2017-01-01

    Stem cells in animals often exhibit a slow cell cycle and/or low transcriptional activity referred to as quiescence. Here, we report that the translational activity in the primordial germ cells (PGCs) of the sea urchin embryo (Strongylocentrotus purpuratus) is quiescent. We measured new protein synthesis with O-propargyl-puromycin and L-homopropargylglycine Click-iT technologies, and determined that these cells synthesize protein at only 6% the level of their adjacent somatic cells. Knockdown of translation of the RNA-binding protein Nanos2 by morpholino antisense oligonucleotides, or knockout of the Nanos2 gene by CRISPR/Cas9 resulted in a significant, but partial, increase (47%) in general translation specifically in the PGCs. We found that the mRNA of the translation factor eEF1A is excluded from the PGCs in a Nanos2-dependent manner, a consequence of a Nanos/Pumilio response element (PRE) in its 3′UTR. In addition to eEF1A, the cytoplasmic pH of the PGCs appears to repress translation and simply increasing the pH also significantly restores translation selectively in the PGCs. We conclude that the PGCs of this sea urchin institute parallel pathways to quiesce translation thoroughly but transiently. PMID:28235822

  2. Model of transient drug diffusion across cornea.

    PubMed

    Zhang, Wensheng; Prausnitz, Mark R; Edwards, Aurélie

    2004-09-30

    A mathematical model of solute transient diffusion across the cornea to the anterior chamber of the eye was developed for topical drug delivery. Solute bioavailability was predicted given solute molecular radius and octanol-to-water distribution coefficient (Phi), ocular membrane ultrastructural parameters, tear fluid hydrodynamics, as well as solute distribution volume (Vd) and clearance rate (Cla) in the anterior chamber. The results suggest that drug bioavailability is primarily determined by solute lipophilicity. In human eyes, bioavailability is predicted to range between 1% and 5% for lipophilic molecules (Phi>1), and to be less than 0.5% for hydrophilic molecules (Phi<0.01). The simulations indicate that the distribution coefficient that maximizes bioavailability is on the order of 10. It was also found that the maximum solute concentration in the anterior chamber (Cmax) and the time needed to reach Cmax significantly depend on Phi, Vd, and Cla. Consistent with experimental findings, model predictions suggest that drug bioavailability can be increased by lowering the conjunctival-to-corneal permeability ratio and reducing precorneal solute drainage. Because of its mechanistic basis, this model will be useful to predict drug transport kinetics and bioavailability for new compounds and in diseased eyes.

  3. GRB 070610: A Curious Galactic Transient

    NASA Astrophysics Data System (ADS)

    Kasliwal, M. M.; Cenko, S. B.; Kulkarni, S. R.; Cameron, P. B.; Nakar, E.; Ofek, E. O.; Rau, A.; Soderberg, A. M.; Campana, S.; Bloom, J. S.; Perley, D. A.; Pollack, L. K.; Barthelmy, S.; Cummings, J.; Gehrels, N.; Krimm, H. A.; Markwardt, C. B.; Sato, G.; Chandra, P.; Frail, D.; Fox, D. B.; Price, P. A.; Berger, E.; Grebenev, S. A.; Krivonos, R. A.; Sunyaev, R. A.

    2008-05-01

    GRB 070610 is a typical high-energy event with a duration of 5 s. Yet within the burst localization we detect a highly unusual X-ray and optical transient, Swift J195509.6+261406. We see high-amplitude X-ray and optical variability on very short timescales even at late times. Using near-infrared imaging assisted by a laser guide star and adaptive optics, we identified the counterpart of Swift J195509.6+261406. Late-time optical and near-infrared imaging constrain the spectral type of the counterpart to be fainter than a K-dwarf, assuming it is of Galactic origin. It is possible that GRB 070610 and Swift J195509.6+261406 are unrelated sources. However, the absence of a typical X-ray afterglow from GRB 070610 in conjunction with the spatial and temporal coincidence of the two motivate us to suggest that the sources are related. The closest (imperfect) analog to Swift J195509.6+261406 is V4641 Sgr, an unusual black hole binary. We suggest that Swift J195509.6+261406 along with V4641 Sgr define a subclass of stellar black hole binaries—the fast X-ray novae. We further suggest that fast X-ray novae are associated with bursts of gamma rays. If so, GRB 070610 defines a new class of celestial gamma-ray bursts and these bursts dominate the long-duration GRB demographics.

  4. GRB070610: A Curious Galactic Transient

    NASA Technical Reports Server (NTRS)

    Kasliwal, M. M.; Kulkrarni. S. R.; Cameron, P. B.; Nakar, E.; Ofek, E. O.; Rau, A.; Soderberg, A. M.; Campana, S.; Bloom, J. S.; Perley, D. A.; hide

    2007-01-01

    GRB 070610 is a typical high-energy event with a duration of 5s.Yet within the burst localization we detect a highly unusual X-ray and optical transient, SwiftJ195509.6+261406. We see high amplitude X-ray and optical variability on very short time scares even at late times. Using near-infrared imaging assisted by a laser guide star and adaptive optics, we identified the counterpart of SwiftJl95509.6+261406. Late-time optical and near-infrared imaging constrain the spectral type of the counterpart to be fainter than a K-dwarf assuming it is of Galactic origin. It is possible that GRB 070610 and Swift J195509.6+261406 are unrelated sources. However, the absence of a typical X-ray afterglow from GRB 070610 in conjunction with the spatial and temporal coincidence of the two motivate us to suggest that the sources are related. The closest (imperfect) analog to Swift J195509.6+261406 is V4641 Sgr, an unusual black hole binary. We suggest that Swift J195509.6+261406 along with V4641 Sgr define a sub-class of stellar black hole binaries -- the fast X-ray novae. We further suggest that fast X-ray novae are associated with bursts of gamma-rays. If so, GRB 070610 defines a new class of celestial gamma-ray bursts and these bursts dominate the long-duration GRB demographics

  5. Transient evoked otoacoustic emissions in rock musicians.

    PubMed

    Høydal, Erik Harry; Lein Størmer, Carl Christian; Laukli, Einar; Stenklev, Niels Christian

    2017-09-01

    Our focus in this study was the assessment of transient evoked otoacoustic emissions (TEOAEs) in a large group of rock musicians. A further objective was to analyse tinnitus among rock musicians as related to TEOAEs. The study was a cross-sectional survey of rock musicians selected at random. A control group was included at random for comparison. We recruited 111 musicians and a control group of 40 non-musicians. Testing was conducted by using clinical examination, pure tone audiometry, TEOAEs and a questionnaire. TEOAE SNR in the half-octave frequency band centred on 4 kHz was significantly lower bilaterally in musicians than controls. This effect was strongly predicted by age and pure-tone hearing threshold levels in the 3-6 kHz range. Bilateral hearing thresholds were significantly higher at 6 kHz in musicians. Twenty percent of the musicians had permanent tinnitus. There was no association between the TEOAE parameters and permanent tinnitus. Our results suggest an incipient hearing loss at 6 kHz in rock musicians. Loss of TEOAE SNR in the 4 kHz half-octave frequency band was observed, but it was related to higher mean 3-6 kHz hearing thresholds and age. A large proportion of rock musicians have permanent tinnitus.

  6. Analysis of electrical transients created by lightning

    NASA Technical Reports Server (NTRS)

    Nanevicz, J. E.; Vance, E. F.

    1980-01-01

    A series of flight tests was conducted using a specially-instrumented NASA Learjet to study the electrical transients created on an aircraft by nearby lightning. The instrumentation included provisions for the time-domain and frequency-domain recording of the electrical signals induced in sensors located both on the exterior and on the interior of the aircraft. The design and calibration of the sensors and associated measuring systems is described together with the results of the flight test measurements. The results indicate that the concept of providing instrumentation to follow the lightning signal from propagation field, to aircraft skin current, to current on interior wiring is basically sound. The results of the measurement indicate that the high frequency signals associated with lightning stroke precursor activity are important in generating electromagnetic noise on the interior of the aircraft. Indeed, the signals produced by the precursors are often of higher amplitude and of longer duration that the pulse produced by the main return stroke.

  7. A Catalog of Coronal "EIT Wave" Transients

    NASA Technical Reports Server (NTRS)

    Thompson, B. J.; Myers, D. C.

    2009-01-01

    Solar and Heliospheric Observatory (SOHO) Extreme ultraviolet Imaging Telescope (EIT) data have been visually searched for coronal "EIT wave" transients over the period beginning from 1997 March 24 and extending through 1998 June 24. The dates covered start at the beginning of regular high-cadence (more than one image every 20 minutes) observations, ending at the four-month interruption of SOHO observations in mid-1998. One hundred and seventy six events are included in this catalog. The observations range from "candidate" events, which were either weak or had insufficient data coverage, to events which were well defined and were clearly distinguishable in the data. Included in the catalog are times of the EIT images in which the events are observed, diagrams indicating the observed locations of the wave fronts and associated active regions, and the speeds of the wave fronts. The measured speeds of the wave fronts varied from less than 50 to over 700 km s(exp -1) with "typical" speeds of 200-400 km s(exp -1).

  8. The placenta: a multifaceted, transient organ

    PubMed Central

    Burton, Graham J.; Fowden, Abigail L.

    2015-01-01

    The placenta is arguably the most important organ of the body, but paradoxically the most poorly understood. During its transient existence, it performs actions that are later taken on by diverse separate organs, including the lungs, liver, gut, kidneys and endocrine glands. Its principal function is to supply the fetus, and in particular, the fetal brain, with oxygen and nutrients. The placenta is structurally adapted to achieve this, possessing a large surface area for exchange and a thin interhaemal membrane separating the maternal and fetal circulations. In addition, it adopts other strategies that are key to facilitating transfer, including remodelling of the maternal uterine arteries that supply the placenta to ensure optimal perfusion. Furthermore, placental hormones have profound effects on maternal metabolism, initially building up her energy reserves and then releasing these to support fetal growth in later pregnancy and lactation post-natally. Bipedalism has posed unique haemodynamic challenges to the placental circulation, as pressure applied to the vena cava by the pregnant uterus may compromise venous return to the heart. These challenges, along with the immune interactions involved in maternal arterial remodelling, may explain complications of pregnancy that are almost unique to the human, including pre-eclampsia. Such complications may represent a trade-off against the provision for a large fetal brain. PMID:25602070

  9. Functional Imaging of Sleep Vertex Sharp Transients

    PubMed Central

    Stern, John M.; Caporro, Matteo; Haneef, Zulfi; Yeh, Hsiang J.; Buttinelli, Carla; Lenartowicz, Agatha; Mumford, Jeanette A.; Parvizi, Josef; Poldrack, Russell A.

    2011-01-01

    Objective The vertex sharp transient (VST) is an electroencephalographic (EEG) discharge that is an early marker of non-REM sleep. It has been recognized since the beginning of sleep physiology research, but its source and function remain mostly unexplained. We investigated VST generation using functional MRI (fMRI). Methods Simultaneous EEG and fMRI were recorded from 7 individuals in drowsiness and light sleep. VST occurrences on EEG were modeled with fMRI using an impulse function convolved with a hemodynamic response function to identify cerebral regions correlating to the VSTs. A resulting statistical image was thresholded at Z>2.3. Results Two hundred VSTs were identified. Significantly increased signal was present bilaterally in medial central, lateral precentral, posterior superior temporal, and medial occipital cortex. No regions of decreased signal were present. Conclusion The regions are consistent with electrophysiologic evidence from animal models and functional imaging of human sleep, but the results are specific to VSTs. The regions principally encompass the primary sensorimotor cortical regions for vision, hearing, and touch. Significance The results depict a network comprising the presumed VST generator and its associated regions. The associated regions functional similarity for primary sensation suggests a role for VSTs in sensory experience during sleep. PMID:21310653

  10. Functional imaging of sleep vertex sharp transients.

    PubMed

    Stern, John M; Caporro, Matteo; Haneef, Zulfi; Yeh, Hsiang J; Buttinelli, Carla; Lenartowicz, Agatha; Mumford, Jeanette A; Parvizi, Josef; Poldrack, Russell A

    2011-07-01

    The vertex sharp transient (VST) is an electroencephalographic (EEG) discharge that is an early marker of non-REM sleep. It has been recognized since the beginning of sleep physiology research, but its source and function remain mostly unexplained. We investigated VST generation using functional MRI (fMRI). Simultaneous EEG and fMRI were recorded from seven individuals in drowsiness and light sleep. VST occurrences on EEG were modeled with fMRI using an impulse function convolved with a hemodynamic response function to identify cerebral regions correlating to the VSTs. A resulting statistical image was thresholded at Z>2.3. Two hundred VSTs were identified. Significantly increased signal was present bilaterally in medial central, lateral precentral, posterior superior temporal, and medial occipital cortex. No regions of decreased signal were present. The regions are consistent with electrophysiologic evidence from animal models and functional imaging of human sleep, but the results are specific to VSTs. The regions principally encompass the primary sensorimotor cortical regions for vision, hearing, and touch. The results depict a network comprising the presumed VST generator and its associated regions. The associated regions functional similarity for primary sensation suggests a role for VSTs in sensory experience during sleep. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  11. Extreme Transients in the High Energy Universe

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2013-01-01

    The High Energy Universe is rich in diverse populations of objects spanning the entire cosmological (time)scale, from our own present-day Milky Way to the re-ionization epoch. Several of these are associated with extreme conditions irreproducible in laboratories on Earth. Their study thus sheds light on the behavior of matter under extreme conditions, such as super-strong magnetic fields (in excess of 10^14 G), high gravitational potentials (e.g., Super Massive Black Holes), very energetic collimated explosions resulting in relativistic jet flows (e.g., Gamma Ray Bursts, exceeding 10^53 ergs). In the last thirty years, my work has been mostly focused on two apparently different but potentially linked populations of such transients: magnetars (highly magnetized neutron stars) and Gamma Ray Bursts (strongly beamed emission from relativistic jets), two populations that constitute unique astrophysical laboratories, while also giving us the tools to probe matter conditions in the Universe to redshifts beyond z=10, when the first stars and galaxies were assembled. I did not make this journey alone I have either led or participated in several international collaborations studying these phenomena in multi-wavelength observations; solitary perfection is not sufficient anymore in the world of High Energy Astrophysics. I will describe this journey, present crucial observational breakthroughs, discuss key results and muse on the future of this field.

  12. PoET: Polarimeters for Energetic Transients

    NASA Technical Reports Server (NTRS)

    McConnell, Mark; Barthelmy, Scott; Hill, Joanne

    2008-01-01

    This presentation focuses on PoET (Polarimeters for Energetic Transients): a Small Explorer mission concept proposed to NASA in January 2008. The principal scientific goal of POET is to measure GRB polarization between 2 and 500 keV. The payload consists of two wide FoV instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2-15 keV and a high energy polarimeter (Gamma-Ray Polarimeter Experiment - GRAPE) that will measure polarization in the 60-500 keV energy range. Spectra will be measured from 2 keV up to 1 MeV. The PoET spacecraft provides a zenith-pointed platform for maximizing the exposure to deep space. Spacecraft rotation will provide a means of effectively dealing with systematics in the polarization response. PoET will provide sufficient sensitivity and sky coverage to measure statistically significant polarization for up to 100 GRBs in a two-year mission. Polarization data will also be obtained for solar flares, pulsars and other sources of astronomical interest.

  13. The transient gamma-ray spectrometer

    NASA Technical Reports Server (NTRS)

    Owens, A.; Baker, R.; Cline, T. L.; Gehrels, N.; Jermakian, J.; Nolan, T.; Ramaty, R.; Smith, G.; Stilwell, D. E.; Teegarden, B. J.

    1991-01-01

    The authors describe the Transient Gamma-Ray Spectrometer (TGRS) to be flown onboard the WIND spacecraft. This instrument is designed to detect cosmic gamma-ray bursts over the energy range of 20 keV to 10 MeV with an expected spectroscopic resolution of 2 keV at 1 MeV (E/Delta-E = 500). The active detection element is a 215-cu cm high-purity n-type Ge crystal cooled to cryogenic temperatures by a passive radiative cooler. The geometric field of view (FOV) defined by the cooler is 170 deg FWFM. Burst data are stored directly in an onboard 2.75-Mb burst memory with an absolute timing accuracy of +/-1.5 ms. This capacity is sufficient to store the entire spectral data set of all but the largest bursts. In addition to burst measurements, the instrument will also study solar flares, search for possible diffuse background lines, and monitor the 511-keV positron annihilation radiation from the galactic center. The experiment is scheduled to be launched on a Delta II launch vehicle from Cape Canaveral on December 31, 1992.

  14. Transient Receptor Potential Channels in the Vasculature

    PubMed Central

    Earley, Scott; Brayden, Joseph E.

    2015-01-01

    The mammalian genome encodes 28 distinct members of the transient receptor potential (TRP) superfamily of cation channels, which exhibit varying degrees of selectivity for different ionic species. Multiple TRP channels are present in all cells and are involved in diverse aspects of cellular function, including sensory perception and signal transduction. Notably, TRP channels are involved in regulating vascular function and pathophysiology, the focus of this review. TRP channels in vascular smooth muscle cells participate in regulating contractility and proliferation, whereas endothelial TRP channel activity is an important contributor to endothelium-dependent vasodilation, vascular wall permeability, and angiogenesis. TRP channels are also present in perivascular sensory neurons and astrocytic endfeet proximal to cerebral arterioles, where they participate in the regulation of vascular tone. Almost all of these functions are mediated by changes in global intracellular Ca2+ levels or subcellular Ca2+ signaling events. In addition to directly mediating Ca2+ entry, TRP channels influence intracellular Ca2+ dynamics through membrane depolarization associated with the influx of cations or through receptor- or store-operated mechanisms. Dysregulation of TRP channels is associated with vascular-related pathologies, including hypertension, neointimal injury, ischemia-reperfusion injury, pulmonary edema, and neurogenic inflammation. In this review, we briefly consider general aspects of TRP channel biology and provide an in-depth discussion of the functions of TRP channels in vascular smooth muscle cells, endothelial cells, and perivascular cells under normal and pathophysiological conditions. PMID:25834234

  15. Three years of Transients with Fermi GBM

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2012-01-01

    The Gamma-ray Burst Monitor (GBM) is an all-sky monitoring instrument, sensitive between 8 keV and 40 MeV, with a primary objective of supporting the Large Area Telescope (LAT) in observations of Gamma-Ray Bursts (GRBs). Both instruments are part of the Fermi Gamma-ray Space Telescope. Together, the GBM and LAT instruments have provided ground-breaking measurements of GRBs that have, after 10 years of focus on GRB afterglows, inspired renewed interest in the prompt emission phase of GRBs and the physical mechanisms that fuel them. In addition to GRB science, GBM has made significant contributions to the astrophysics of galactic transient sources including long-term variations in the Crab nebula, spin state transitions in accretion powered pulsars, state transitions in black hole X-ray binaries, and unprecedented time-resolved spectral studies of soft gamma-ray repeater bursts. Closer to home, GBM also contributes to solar flare and terrestrial gamma flash science.

  16. Thermal Transients in District Heating Systems

    DOE PAGES

    Chertkov, Michael; Novitsky, Nikolai N.

    2018-01-18

    Heat fluxes in a district heating pipeline systems need to be controlled on the scale from minutes to an hour to adjust to evolving demand. There are two principal ways to control the heat flux - keep temperature fixed but adjust velocity of the carrier (typically water) or keep the velocity flow steady but then adjust temperature at the heat producing source (heat plant). Here, we study the latter scenario, commonly used for operations in Russia and Nordic countries, and analyze dynamics of the heat front as it propagates through the system. Steady velocity flows in the district heating pipelinesmore » are typically turbulent and incompressible. Changes in the heat, on either consumption or production sides, lead to slow transients which last from tens of minutes to hours. We classify relevant physical phenomena in a single pipe, e.g. turbulent spread of the turbulent front. We then explain how to describe dynamics of temperature and heat flux evolution over a network efficiently and illustrate the network solution on a simple example involving one producer and one consumer of heat connected by “hot” and “cold” pipes. We conclude the manuscript motivating future research directions.« less

  17. Incidental Transient Cortical Blindness after Lung Resection.

    PubMed

    Oncel, Murat; Sunam, Guven Sadi; Varoglu, Asuman Orhan; Karabagli, Hakan; Yildiran, Huseyin

    2016-03-01

    Transient vision loss after major surgical procedures is a rare clinical complication. The most common etiologies are cardiac, spinal, head, and neck surgeries. There has been no report on vision loss after lung resection. A 65-year-old man was admitted to our clinic with lung cancer. Resection was performed using right upper lobectomy with no complications. Cortical blindness developed 12 hours later in the postoperative period. Results from magnetic resonance imaging and diffusion-weighted investigations were normal. The neurologic examination was normal. The blood glucose level was 92 mg/dL and blood gas analysis showed a PO 2 of 82 mm Hg. After 24 hours, the patient began to see and could count fingers, and his vision was fully restored within 72 hours after this point. Autonomic dysfunction due to impaired microvascular structures in diabetes mellitus may induce posterior circulation dysfunction, even when the hemodynamic state is normal in the perioperative period. The physician must keep in mind that vision loss may occur after lung resection due to autonomic dysfunction, especially in older patients with diabetes mellitus.

  18. Three Decades of High Energy Transients

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2012-01-01

    Gamma-Ray Bursts are the most brilliant explosions in space. The first GRB was discovered on 1967, just over 40 years ago. It took several years and multiple generations of space and ground instruments to unravel some of the mysteries of this phenomenon. However, many questions remain open today. I will discuss the history, evolution and current status of the GRB field and its contributions in our understanding of the transient high energy sky. Finally, I will describe how GRBs can be utilized in future missions as tools, to probe the cosmic chemical evolution of the Universe Magnetars are magnetically powered rotating neutron stars with extreme magnetic fields (over 10(exp 14) Gauss). They were discovered in the X- and gamma-rays where they predominantly emit their radiation. Very few sources (roughly 24) have been found since their discovery in 1987. NASA's Fermi Gamma-ray Space Telescope was launched June 11, 2009; since then the Fermi Gamma-ray Burst Monitor (GBM) recorded emission from several magnetar sources. In total, six new sources were discovered between 2008 and 2011, with a synergy between Swift, RXTE, Fermi and the Interplanetary Network (IPN). I will give a short history of magnetars and describe how this, once relatively esoteric field, has emerged as a link between several astrophysical areas including Gamma-Ray Bursts.

  19. Cascade flutter analysis with transient response aerodynamics

    NASA Technical Reports Server (NTRS)

    Bakhle, Milind A.; Mahajan, Aparajit J.; Keith, Theo G., Jr.; Stefko, George L.

    1991-01-01

    Two methods for calculating linear frequency domain aerodynamic coefficients from a time marching Full Potential cascade solver are developed and verified. In the first method, the Influence Coefficient, solutions to elemental problems are superposed to obtain the solutions for a cascade in which all blades are vibrating with a constant interblade phase angle. The elemental problem consists of a single blade in the cascade oscillating while the other blades remain stationary. In the second method, the Pulse Response, the response to the transient motion of a blade is used to calculate influence coefficients. This is done by calculating the Fourier Transforms of the blade motion and the response. Both methods are validated by comparison with the Harmonic Oscillation method and give accurate results. The aerodynamic coefficients obtained from these methods are used for frequency domain flutter calculations involving a typical section blade structural model. An eigenvalue problem is solved for each interblade phase angle mode and the eigenvalues are used to determine aeroelastic stability. Flutter calculations are performed for two examples over a range of subsonic Mach numbers.

  20. [Takotsubo syndrome. Transient left ventricular dyskinesia].

    PubMed

    Pérez Pérez, F M; Sánchez Salado, J

    2014-03-01

    The Takotsubo syndrome, also called transient apical dyskinesia syndrome, was first described in Japan in the 1990s. It is a rare entity found in almost 1% of all patients with suspicion of acute coronary syndrome. It usually affects postmenopausal women with a few cardiovascular risk factors. It is characterized by angina-type chest pain, electrocardiographic changes, elevation of the enzymes of myocardial injury, absence of coronary obstruction on angiography, and a characteristic left ventricular anteroapical dyskinesia, which returns to normal within a few days. Severe emotional stress is the most common trigger for this syndrome. The aetiopathogenesis of this syndrome remains to be defined. This syndrome has been considered a clinical condition since 2001, when a series of 88 cases was published. It is a disease with a partially known mechanism, characterised by the morphology adopted by the left ventricle secondary to hypokinesis or dyskinesia of the apical segments, and hypercontractility of basal segments. Unlike acute coronary syndrome, patients with left ventricle dysfunction do not have atherothrombotic disease in the coronary arteries. In addition, the alterations described are reversible. Some clinical diagnostic criteria have been proposed, although they are still controversial, as well as in the complementary examinations required for diagnosis. Copyright © 2012 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.

  1. Thermal Transients in District Heating Systems

    SciT

    Chertkov, Michael; Novitsky, Nikolai N.

    Heat fluxes in a district heating pipeline systems need to be controlled on the scale from minutes to an hour to adjust to evolving demand. There are two principal ways to control the heat flux - keep temperature fixed but adjust velocity of the carrier (typically water) or keep the velocity flow steady but then adjust temperature at the heat producing source (heat plant). Here, we study the latter scenario, commonly used for operations in Russia and Nordic countries, and analyze dynamics of the heat front as it propagates through the system. Steady velocity flows in the district heating pipelinesmore » are typically turbulent and incompressible. Changes in the heat, on either consumption or production sides, lead to slow transients which last from tens of minutes to hours. We classify relevant physical phenomena in a single pipe, e.g. turbulent spread of the turbulent front. We then explain how to describe dynamics of temperature and heat flux evolution over a network efficiently and illustrate the network solution on a simple example involving one producer and one consumer of heat connected by “hot” and “cold” pipes. We conclude the manuscript motivating future research directions.« less

  2. Automated Fluid Feature Extraction from Transient Simulations

    NASA Technical Reports Server (NTRS)

    Haimes, Robert; Lovely, David

    1999-01-01

    In the past, feature extraction and identification were interesting concepts, but not required to understand the underlying physics of a steady flow field. This is because the results of the more traditional tools like iso-surfaces, cuts and streamlines were more interactive and easily abstracted so they could be represented to the investigator. These tools worked and properly conveyed the collected information at the expense of much interaction. For unsteady flow-fields, the investigator does not have the luxury of spending time scanning only one "snap-shot" of the simulation. Automated assistance is required in pointing out areas of potential interest contained within the flow. This must not require a heavy compute burden (the visualization should not significantly slow down the solution procedure for co-processing environments like pV3). And methods must be developed to abstract the feature and display it in a manner that physically makes sense. The following is a list of the important physical phenomena found in transient (and steady-state) fluid flow: (1) Shocks, (2) Vortex cores, (3) Regions of recirculation, (4) Boundary layers, (5) Wakes. Three papers and an initial specification for the (The Fluid eXtraction tool kit) FX Programmer's guide were included. The papers, submitted to the AIAA Computational Fluid Dynamics Conference, are entitled : (1) Using Residence Time for the Extraction of Recirculation Regions, (2) Shock Detection from Computational Fluid Dynamics results and (3) On the Velocity Gradient Tensor and Fluid Feature Extraction.

  3. Automated Fluid Feature Extraction from Transient Simulations

    NASA Technical Reports Server (NTRS)

    Haimes, Robert

    1998-01-01

    In the past, feature extraction and identification were interesting concepts, but not required to understand the underlying physics of a steady flow field. This is because the results of the more traditional tools like iso-surfaces, cuts and streamlines were more interactive and easily abstracted so they could be represented to the investigator. These tools worked and properly conveyed the collected information at the expense of much interaction. For unsteady flow-fields, the investigator does not have the luxury of spending time scanning only one 'snap-shot' of the simulation. Automated assistance is required in pointing out areas of potential interest contained within the flow. This must not require a heavy compute burden (the visualization should not significantly slow down the solution procedure for co-processing environments like pV3). And methods must be developed to abstract the feature and display it in a manner that physically makes sense. The following is a list of the important physical phenomena found in transient (and steady-state) fluid flow: Shocks; Vortex ores; Regions of Recirculation; Boundary Layers; Wakes.

  4. Transient threshold shift after gunshot noise exposure.

    PubMed

    Saedi, B; Ghasemi, M; Motiee, M; Mojtahed, M; Safavi, A

    2013-01-01

    Many people, such as soldiers, are routinely exposed to gunshot noise during target practice. It is suspected that this high-intensity noise may affect audition through repeated Transient Threshold Shifts (TTS); it can also mechanically alter auditory components such as waves. This study investigates the scope of gunshot noise from the AK-47 rifle (Kalashnikov) and the impact on the shooters' audition. Forty soldiers (80 ears) were recruited in this study. They were all young and being exposed to gunshot noise for the first time. Gunshot characteristics were measured before exposure. The soldiers underwent auditory evaluation with Pure Tone Audiometry (PTA) and Oto-Acoustic Emission (OAE) once before exposure and immediately (less than one hour) after exposure. The AK-47 gunshot noise pressure level varied between L(AIm) = 73.7 dBA to L(AIm) = 111.4 dBA. Fourteen participants had subclinical hearing impairment in their pre-exposure evaluation; this number increased to 16 after the exposure. Six months post-exposure and later, the number of cases with impairment had fallen to eight (improvement in 50%). Both pre- and post-exposure OAE results were within normal values, while PTA results indicated a significant threshold alteration only at 6 kHz. The results of this study confirm that exposure to gunshot noise with no ear protection can represent a significant hazard for auditory function, especially at higher frequencies.

  5. Hippocampal CA1 Ripples as Inhibitory Transients

    PubMed Central

    Krishnan, Giri P; Fellous, Jean-Marc; Bazhenov, Maxim

    2016-01-01

    Memories are stored and consolidated as a result of a dialogue between the hippocampus and cortex during sleep. Neurons active during behavior reactivate in both structures during sleep, in conjunction with characteristic brain oscillations that may form the neural substrate of memory consolidation. In the hippocampus, replay occurs within sharp wave-ripples: short bouts of high-frequency activity in area CA1 caused by excitatory activation from area CA3. In this work, we develop a computational model of ripple generation, motivated by in vivo rat data showing that ripples have a broad frequency distribution, exponential inter-arrival times and yet highly non-variable durations. Our study predicts that ripples are not persistent oscillations but result from a transient network behavior, induced by input from CA3, in which the high frequency synchronous firing of perisomatic interneurons does not depend on the time scale of synaptic inhibition. We found that noise-induced loss of synchrony among CA1 interneurons dynamically constrains individual ripple duration. Our study proposes a novel mechanism of hippocampal ripple generation consistent with a broad range of experimental data, and highlights the role of noise in regulating the duration of input-driven oscillatory spiking in an inhibitory network. PMID:27093059

  6. TEMPEST. Transient 3-D Thermal-Hydraulic

    SciT

    Eyler, L.L.

    TEMPEST is a transient, three-dimensional, hydrothermal program that is designed to analyze a range of coupled fluid dynamic and heat transfer systems of particular interest to the Fast Breeder Reactor (FBR) thermal-hydraulic design community. The full three-dimensional, time-dependent equations of motion, continuity, and heat transport are solved for either laminar or turbulent fluid flow, including heat diffusion and generation in both solid and liquid materials. The equations governing mass, momentum, and energy conservation for incompressible flows and small density variations (Boussinesq approximation) are solved using finite-difference techniques. Analyses may be conducted in either cylindrical or Cartesian coordinate systems. Turbulence ismore » treated using a two-equation model. Two auxiliary plotting programs, SEQUEL and MANPLOT, for use with TEMPEST output are included. SEQUEL may be operated in batch or interactive mode; it generates data required for vector plots, contour plots of scalar quantities, line plots, grid and boundary plots, and time-history plots. MANPLOT reads the SEQUEL-generated data and creates the hardcopy plots. TEMPEST can be a valuable hydrothermal design analysis tool in areas outside the intended FBR thermal-hydraulic design community.« less

  7. Transient dynamics capability at Sandia National Laboratories

    NASA Technical Reports Server (NTRS)

    Attaway, Steven W.; Biffle, Johnny H.; Sjaardema, G. D.; Heinstein, M. W.; Schoof, L. A.

    1993-01-01

    A brief overview of the transient dynamics capabilities at Sandia National Laboratories, with an emphasis on recent new developments and current research is presented. In addition, the Sandia National Laboratories (SNL) Engineering Analysis Code Access System (SEACAS), which is a collection of structural and thermal codes and utilities used by analysts at SNL, is described. The SEACAS system includes pre- and post-processing codes, analysis codes, database translation codes, support libraries, Unix shell scripts for execution, and an installation system. SEACAS is used at SNL on a daily basis as a production, research, and development system for the engineering analysts and code developers. Over the past year, approximately 190 days of CPU time were used by SEACAS codes on jobs running from a few seconds up to two and one-half days of CPU time. SEACAS is running on several different systems at SNL including Cray Unicos, Hewlett Packard PH-UX, Digital Equipment Ultrix, and Sun SunOS. An overview of SEACAS, including a short description of the codes in the system, are presented. Abstracts and references for the codes are listed at the end of the report.

  8. Gas-core reactor power transient analysis

    NASA Technical Reports Server (NTRS)

    Kascak, A. F.

    1972-01-01

    The gas core reactor is a proposed device which features high temperatures. It has applications in high specific impulse space missions, and possibly in low thermal pollution MHD power plants. The nuclear fuel is a ball of uranium plasma radiating thermal photons as opposed to gamma rays. This thermal energy is picked up before it reaches the solid cavity liner by an inflowing seeded propellant stream and convected out through a rocket nozzle. A wall-burnout condition will exist if there is not enough flow of propellant to convect the energy back into the cavity. A reactor must therefore operate with a certain amount of excess propellant flow. Due to the thermal inertia of the flowing propellant, the reactor can undergo power transients in excess of the steady-state wall burnout power for short periods of time. The objective of this study was to determine how long the wall burnout power could be exceeded without burning out the cavity liner. The model used in the heat-transfer calculation was one-dimensional, and thermal radiation was assumed to be a diffusion process.

  9. Transient Heat Conduction Simulation around Microprocessor Die

    NASA Astrophysics Data System (ADS)

    Nishi, Koji

    This paper explains about fundamental formula of calculating power consumption of CMOS (Complementary Metal-Oxide-Semiconductor) devices and its voltage and temperature dependency, then introduces equation for estimating power consumption of the microprocessor for notebook PC (Personal Computer). The equation is applied to heat conduction simulation with simplified thermal model and evaluates in sub-millisecond time step calculation. In addition, the microprocessor has two major heat conduction paths; one is from the top of the silicon die via thermal solution and the other is from package substrate and pins via PGA (Pin Grid Array) socket. Even though the dominant factor of heat conduction is the former path, the latter path - from package substrate and pins - plays an important role in transient heat conduction behavior. Therefore, this paper tries to focus the path from package substrate and pins, and to investigate more accurate method of estimating heat conduction paths of the microprocessor. Also, cooling performance expression of heatsink fan is one of key points to assure result with practical accuracy, while finer expression requires more computation resources which results in longer computation time. Then, this paper discusses the expression to minimize computation workload with a practical accuracy of the result.

  10. Large Angle Transient Dynamics (LATDYN) user's manual

    NASA Technical Reports Server (NTRS)

    Abrahamson, A. Louis; Chang, Che-Wei; Powell, Michael G.; Wu, Shih-Chin; Bingel, Bradford D.; Theophilos, Paula M.

    1991-01-01

    A computer code for modeling the large angle transient dynamics (LATDYN) of structures was developed to investigate techniques for analyzing flexible deformation and control/structure interaction problems associated with large angular motions of spacecraft. This type of analysis is beyond the routine capability of conventional analytical tools without simplifying assumptions. In some instances, the motion may be sufficiently slow and the spacecraft (or component) sufficiently rigid to simplify analyses of dynamics and controls by making pseudo-static and/or rigid body assumptions. The LATDYN introduces a new approach to the problem by combining finite element structural analysis, multi-body dynamics, and control system analysis in a single tool. It includes a type of finite element that can deform and rotate through large angles at the same time, and which can be connected to other finite elements either rigidly or through mechanical joints. The LATDYN also provides symbolic capabilities for modeling control systems which are interfaced directly with the finite element structural model. Thus, the nonlinear equations representing the structural model are integrated along with the equations representing sensors, processing, and controls as a coupled system.

  11. Modulare und durchgängige Produktmodelle als Erfolgsfaktor zur Bedienung einer Omni-Channel-Architektur - PLM 4.0

    NASA Astrophysics Data System (ADS)

    Golovatchev, Julius; Felsmann, Marcus

    Mit der Transformation der Wertschöpfungsstrukturen von Utility 1.0 zu Utility 4.0 erfolgt offensichtlich auch eine Veränderung des Produkts. Vor dem Hintergrund disruptiver Technologien (IoT, Big Data, Cloud, Robotics etc.) und auch gesellschaftlicher Veränderungen entstehen ständig neue Geschäftsmodelle und Produkte, die über die reine Versorgungsdienstleistung (z. B. Strom) hinausgehen. Dabei muss der wertvolle Rohstoff Produktdaten für smarte Produkte durchgängiger und schneller nutzbar gemacht werden. Die modularen und durchgängigen Produktstrukturen leisten einen Beitrag zur Beherrschung von Komplexität und stellen somit einen wesentlichen Hebel für erfolgreiche Produktentwicklung und -management dar. In diesem Beitrag werden Ansätze beschrieben, wie es den vor der Herausforderung Utility 4.0 stehenden Unternehmen gelingen kann, Smart-Energy-Produkte so zu modellieren, dass sie die Interoperabilität der einzelnen Produktionsmodule sicherstellt und ein Ende-zu-Ende-Management ermöglicht.

  12. Book Review: Beitraege zur Astronomiegeschichte, Band 5 (Acta Historica Astronomiae Vol. 15)

    NASA Astrophysics Data System (ADS)

    Duerbeck, H. W.; Dick, W. R.; Hamel, J.

    2002-12-01

    The 15th volume of the Acta Historica Astronomiae is at the same time the fifth collection of essays on the history of astronomy (Beitraege zur Astronomiegeschichte, Band 5), edited by the historians of astronomy W.R. Dick (Potsdam) and J. Hamel (Berlin). Besides a few short notices and book reviews, the book contains 11 major articles, which deal with astronomical topics covering the time from the 16th to the 20th centuries. The first article, on the analysis and interpretation of historical horoscopes as a source of the history of science, is based on the inaugural lecture of its author, Guenther Oestmann. After a general introduction, which deals with the principles of horoscope making, the author discusses the horoscope of Count Heinrich Ranzau (1526-1598), the Danish governor of Schleswig-Holstein, who was a friend of Tycho Brahe. Oestmann shows that the astronomical-mathematical basis of such a horoscope can be reconstructed and interpreted. However, it is hardly possible to gain an insight in the process how the interpretation of a horoscope was done in detail. The second and third articles, by Franz Daxecker, deal with Athanasius Kircher and Christoph Scheiner, two catholic astronomers of the 17th century. Kircher's Organum Mathematicum is a calculating device that can be used in the fields of arithmetic, geometry, chronology, astronomy, astrology and others. The author provides extracts of the description of the Organum taken from a book by Caspar Schott, which deal with chronology and astronomy. A photograph of the Organum indicates that this tool consists of a set of tables glued on wooden or cardboard, but details of its contents and applications remain pretty obscure for the reader - a few elaborated examples would have been helpful. The second paper deals with the life of Christoph Scheiner SJ, the co-discoverer of sunspots (next to Galileo), after leaving Rome in 1633 - the year of the Galileo trial. Scheiner spent his later years in the Austrian and

  13. Spontaneous calcium transients in human neural progenitor cells mediated by transient receptor potential channels.

    PubMed

    Morgan, Peter J; Hübner, Rayk; Rolfs, Arndt; Frech, Moritz J

    2013-09-15

    Calcium signals affect many developmental processes, including proliferation, migration, survival, and apoptosis, processes that are of particular importance in stem cells intended for cell replacement therapies. The mechanisms underlying Ca(2+) signals, therefore, have a role in determining how stem cells respond to their environment, and how these responses might be controlled in vitro. In this study, we examined the spontaneous Ca(2+) activity in human neural progenitor cells during proliferation and differentiation. Pharmacological characterization indicates that in proliferating cells, most activity is the result of transient receptor potential (TRP) channels that are sensitive to Gd(3+) and La(3+), with the more subtype selective antagonist Ruthenium red also reducing activity, suggesting the involvement of transient receptor potential vanilloid (TRPV) channels. In differentiating cells, Gd(3+) and La(3+)-sensitive TRP channels also appear to underlie the spontaneous activity; however, no sub-type-specific antagonists had any effect. Protein levels of TRPV2 and TRPV3 decreased in differentiated cells, which is demonstrated by western blot. Thus, it appears that TRP channels represent the main route of Ca(2+) entry in human neural progenitor cells (hNPCs), but the responsible channel types are subject to substitution under differentiating conditions. The level of spontaneous activity could be increased and decreased by lowering and raising the extracellular K(+) concentration. Proliferating cells in low K(+) slowed the cell cycle, with a disproportionate increased percentage of cells in G1 phase and a reduction in S phase. Taken together, these results suggest a link between external K(+) concentration, spontaneous Ca(2+) transients, and cell cycle distribution, which is able to influence the fate of stem and progenitor cells.

  14. Transient radiative transfer in a scattering slab considering polarization.

    PubMed

    Yi, Hongliang; Ben, Xun; Tan, Heping

    2013-11-04

    The characteristics of the transient and polarization must be considered for a complete and correct description of short-pulse laser transfer in a scattering medium. A Monte Carlo (MC) method combined with a time shift and superposition principle is developed to simulate transient vector (polarized) radiative transfer in a scattering medium. The transient vector radiative transfer matrix (TVRTM) is defined to describe the transient polarization behavior of short-pulse laser propagating in the scattering medium. According to the definition of reflectivity, a new criterion of reflection at Fresnel surface is presented. In order to improve the computational efficiency and accuracy, a time shift and superposition principle is applied to the MC model for transient vector radiative transfer. The results for transient scalar radiative transfer and steady-state vector radiative transfer are compared with those in published literatures, respectively, and an excellent agreement between them is observed, which validates the correctness of the present model. Finally, transient radiative transfer is simulated considering the polarization effect of short-pulse laser in a scattering medium, and the distributions of Stokes vector in angular and temporal space are presented.

  15. Capture-recapture survival models taking account of transients

    Pradel, R.; Hines, J.E.; Lebreton, J.D.; Nichols, J.D.

    1997-01-01

    The presence of transient animals, common enough in natural populations, invalidates the estimation of survival by traditional capture- recapture (CR) models designed for the study of residents only. Also, the study of transit is interesting in itself. We thus develop here a class of CR models to describe the presence of transients. In order to assess the merits of this approach we examme the bias of the traditional survival estimators in the presence of transients in relation to the power of different tests for detecting transients. We also compare the relative efficiency of an ad hoc approach to dealing with transients that leaves out the first observation of each animal. We then study a real example using lazuli bunting (Passerina amoena) and, in conclusion, discuss the design of an experiment aiming at the estimation of transience. In practice, the presence of transients is easily detected whenever the risk of bias is high. The ad hoc approach, which yields unbiased estimates for residents only, is satisfactory in a time-dependent context but poorly efficient when parameters are constant. The example shows that intermediate situations between strict 'residence' and strict 'transience' may exist in certain studies. Yet, most of the time, if the study design takes into account the expected length of stay of a transient, it should be possible to efficiently separate the two categories of animals.

  16. Walker circulation in a transient climate

    NASA Astrophysics Data System (ADS)

    Plesca, Elina; Grützun, Verena; Buehler, Stefan A.

    2016-04-01

    The tropical overturning circulations modulate the heat exchange across the tropics and between the tropics and the poles. The anthropogenic influence on the climate system will affect these circulations, impacting the dynamics of the Earth system. In this work we focus on the Walker circulation. We investigate its temporal and spatial dynamical changes and their link to other climate features, such as surface and sea-surface temperature patterns, El-Niño Southern Oscillation (ENSO), and ocean heat-uptake, both at global and regional scale. In order to determine the impact of anthropogenic climate change on the tropical circulation, we analyze the outputs of 28 general circulation models (GCMs) from the CMIP5 project. We use the experiment with 1% year-1 increase in CO2 concentration from pre-industrial levels to quadrupling of the concentration. Consistent with previous studies (ex. Ma and Xie 2013), we find that for this experiment most GCMs associate a weakening Walker circulation to a warming transient climate. Due to the role of the Walker Pacific cell in the meridional heat and moisture transport across the tropical Pacific and also the connection to ENSO, we find that a weakened Walker circulation correlates with more extreme El-Niño events, although without a change in their frequency. The spatial analysis of the Pacific Walker cell suggests an eastward displacement of the ascending branch, which is consistent with positive SST anomalies over the tropical Pacific and the link of the Pacific Walker cell to ENSO. Recent studies (ex. England et al. 2014) have linked a strengthened Walker circulation to stronger ocean heat uptake, especially in the western Pacific. The inter-model comparison of the correlation between Walker circulation intensity and ocean heat uptake does not convey a robust response for the investigated experiment. However, there is some evidence that a stronger weakening of the Walker circulation is linked to a higher transient climate

  17. Contribution of EEG in transient neurological deficits.

    PubMed

    Lozeron, Pierre; Tcheumeni, Nadine Carole; Turki, Sahar; Amiel, Hélène; Meppiel, Elodie; Masmoudi, Sana; Roos, Caroline; Crassard, Isabelle; Plaisance, Patrick; Benbetka, Houria; Guichard, Jean-Pierre; Houdart, Emmanuel; Baudoin, Hélène; Kubis, Nathalie

    2018-01-01

    Identification of stroke mimics and 'chameleons' among transient neurological deficits (TND) is critical. Diagnostic workup consists of a brain imaging study, for a vascular disease or a brain tumour and EEG, for epileptiform discharges. The precise role of EEG in this diagnostic workup has, however, never been clearly delineated. However, this could be crucial in cases of atypical or incomplete presentation with consequences on disease management and treatment. We analysed the EEG patterns on 95 consecutive patients referred for an EEG within 7 days of a TND with diagnostic uncertainty. Patients were classified at the discharge or the 3-month follow-up visit as: 'ischemic origin', 'migraine aura', 'focal seizure', and 'other'. All patients had a brain imaging study. EEG characteristics were correlated to the TND symptoms, imaging study, and final diagnosis. Sixty four (67%) were of acute onset. Median symptom duration was 45 min. Thirty two % were 'ischemic', 14% 'migraine aura', 19% 'focal seizure', and 36% 'other' cause. EEGs were recorded with a median delay of 1.6 day after symptoms onset. Forty EEGs (42%) were abnormal. Focal slow waves were the most common finding (43%), also in the ischemic group (43%), whether patients had a typical presentation or not. Epileptiform discharges were found in three patients, one with focal seizure and two with migraine aura. Non-specific EEG focal slowing is commonly found in TND, and may last several days. We found no difference in EEG presentation between stroke mimics and stroke chameleons, and between other diagnoses.

  18. The SCEC geodetic transient detection validation exercise

    Lohman, Rowena B.; Murray, Jessica R.

    2013-01-01

    Over the past decade the number and size of continuously operating Global Positioning System (GPS) networks has grown substantially worldwide. A steadily increasing volume of freely available GPS measurements, combined with the application of new approaches for mining these data for signals of interest, has led to the identification of a large and diverse collection of time‐varying Earth processes. One phenomenon that has been observed is transient fault slip (also termed slow slip events or silent earthquakes) occurring over time spans of days to years (e.g., Linde et al., 1996; Hirose et al., 1999; Dragert et al., 2001; Miller et al., 2002; Kostoglodov et al., 2003; Douglas et al., 2005; Shelly et al., 2006; Ide et al., 2007; Lohman and McGuire, 2007; Schwartz and Rokosky, 2007; Szeliga et al., 2008). Such events have been widely observed in subduction zones but are also found in other tectonic settings (Linde et al., 1996; Cervelli et al., 2002; Murray and Segall, 2005; Lohman and McGuire, 2007; Montgomery‐Brown et al., 2009; Shelly, 2010; and references therein). Although retrospective study of slow‐slip events using geodetic observations is driving the formulation of new models for fault‐zone behavior and constitutive laws (e.g., Lapusta et al., 2000; Liu and Rice, 2007; Lapusta and Liu, 2009; Segall and Bradley, 2012a), much of the research on near‐real‐time detection and characterization of anomalous behaviors along fault zones has focused solely on the use of seismic tremor (e.g., Rogers and Dragert, 2003; Shelly et al., 2006; Ito et al., 2007).

  19. Acute transient hemiparesis induced by lightning strike.

    PubMed

    Rahmani, Seyed Hesam; Faridaalaee, Gholamreza; Jahangard, Samira

    2015-07-01

    According to data from the National Oceanic and Atmospheric Administration,in the years from 1959 to 1994, lightning was responsible for more than 3000 deaths and nearly 10,000 casualties. The most important characteristic features of lightning injuries are multisystem involvement and widely variable severity. Lightning strikes are primarily a neurologic injury that affects all 3 components of the nervous system: central, autonomic,and peripheral. Neurologic complications of lightning strikes vary from transient benign symptoms to permanent disability. Many patients experience a temporary paralysis called keraunoparalysis. Here we reported a 22-year-old mountaineer man with complaining of left sided hemiparesis after being hit by a lightning strike in the mountain 3 hours ago. There was no loss of consciousness at hitting time. On arrival the patient was alert, awake and hemodynamically stable. In neurologic examination cranial nerves were intact, left sided upper and lower extremity muscle force was I/V with a combination of complete sensory loss, and right-sided muscle force and sensory examination were normal. There is not any evidence of significant vascular impairment in the affected extremities. Brain MRI and CT scan and cervical MRI were normal. During 2 days of admission, with intravenous hydration, heparin 5000 unit SC q12hr and physical therapy of the affected limbs, motor and sensory function improved and was normal except mild paresthesia. He was discharged 1 day later for outpatient follow up while vitamin B1 100mg orally was prescribed.Paresthesia improved after 3 days without further sequels.

  20. Spatial fluctuations in transient creep deformation

    NASA Astrophysics Data System (ADS)

    Laurson, Lasse; Rosti, Jari; Koivisto, Juha; Miksic, Amandine; Alava, Mikko J.

    2011-07-01

    We study the spatial fluctuations of transient creep deformation of materials as a function of time, both by digital image correlation (DIC) measurements of paper samples and by numerical simulations of a crystal plasticity or discrete dislocation dynamics model. This model has a jamming or yielding phase transition, around which power law or Andrade creep is found. During primary creep, the relative strength of the strain rate fluctuations increases with time in both cases—the spatially averaged creep rate obeys the Andrade law epsilont ~ t - 0.7, while the time dependence of the spatial fluctuations of the local creep rates is given by Δepsilont ~ t - 0.5. A similar scaling for the fluctuations is found in the logarithmic creep regime that is typically observed for lower applied stresses. We review briefly some classical theories of Andrade creep from the point of view of such spatial fluctuations. We consider these phenomenological, time-dependent creep laws in terms of a description based on a non-equilibrium phase transition separating evolving and frozen states of the system when the externally applied load is varied. Such an interpretation is discussed further by the data collapse of the local deformations in the spirit of absorbing state/depinning phase transitions, as well as deformation-deformation correlations and the width of the cumulative strain distributions. The results are also compared with the order parameter fluctuations observed close to the depinning transition of the 2d linear interface model or the quenched Edwards-Wilkinson equation.

  1. Robotic exoskeleton assessment of transient ischemic attack.

    PubMed

    Simmatis, Leif; Krett, Jonathan; Scott, Stephen H; Jin, Albert Y

    2017-01-01

    We used a robotic exoskeleton to quantify specific patterns of abnormal upper limb motor behaviour in people who have had transient ischemic attack (TIA). A cohort of people with TIA was recruited within two weeks of symptom onset. All individuals completed a robotic-based assessment of 8 behavioural tasks related to upper limb motor and proprioceptive function, as well as cognitive function. Robotic task performance was compared to a large cohort of controls without neurological impairments corrected for the influence of age. Impairment in people with TIA was defined as performance below the 5th percentile of controls. Participants with TIA were also assessed with the National Institutes of Health Stroke Scale (NIHSS) score, Chedoke-McMaster Stroke Assessment (CMSA) of the arm, the Behavioural Inattention Test (BIT), the Purdue pegboard test (PPB), and the Montreal Cognitive Assessment (MoCA). Age-related white matter change (ARWMC), prior infarction and cella-media index (CMI) were assessed from baseline CT scan that was performed within 24 hours of TIA. Acute infarction was assessed from diffusion-weighted imaging in a subset of people with TIA. Twenty-two people with TIA were assessed. Robotic assessment showed impaired upper limb motor function in 7/22 people with TIA patients and upper limb sensory impairment in 4/22 individuals. Cognitive tasks involving robotic assessment of the upper limb were completed in 13 participants, of whom 8 (61.5%) showed significant impairment. Abnormal performance in the CMSA arm inventory was present in 12/22 (54.5%) participants. ARWMC was 11.8 ± 6.4 and CMI was 5.4 ± 1.5. DWI was positive in 0 participants. Quantitative robotic assessment showed that people who have had a TIA display a spectrum of upper limb motor and sensory performance deficits as well as cognitive function deficits despite resolution of symptoms and no evidence of tissue infarction.

  2. Transient nature of late Pleistocene climate variability.

    PubMed

    Crowley, Thomas J; Hyde, William T

    2008-11-13

    Climate in the early Pleistocene varied with a period of 41 kyr and was related to variations in Earth's obliquity. About 900 kyr ago, variability increased and oscillated primarily at a period of approximately 100 kyr, suggesting that the link was then with the eccentricity of Earth's orbit. This transition has often been attributed to a nonlinear response to small changes in external boundary conditions. Here we propose that increasing variablility within the past million years may indicate that the climate system was approaching a second climate bifurcation point, after which it would transition again to a new stable state characterized by permanent mid-latitude Northern Hemisphere glaciation. From this perspective the past million years can be viewed as a transient interval in the evolution of Earth's climate. We support our hypothesis using a coupled energy-balance/ice-sheet model, which furthermore predicts that the future transition would involve a large expansion of the Eurasian ice sheet. The process responsible for the abrupt change seems to be the albedo discontinuity at the snow-ice edge. The best-fit model run, which explains almost 60% of the variance in global ice volume during the past 400 kyr, predicts a rapid transition in the geologically near future to the proposed glacial state. Should it be attained, this state would be more 'symmetric' than the present climate, with comparable areas of ice/sea-ice cover in each hemisphere, and would represent the culmination of 50 million years of evolution from bipolar nonglacial climates to bipolar glacial climates.

  3. Heinrich events modeled in transient glacial simulations

    NASA Astrophysics Data System (ADS)

    Ziemen, Florian; Kapsch, Marie; Mikolajewicz, Uwe

    2017-04-01

    Heinrich events are among the most prominent events of climate variability recorded in proxies across the northern hemisphere. They are the archetype of ice sheet — climate interactions on millennial time scales. Nevertheless, the exact mechanisms that cause Heinrich events are still under debate, and their climatic consequences are far from being fully understood. We address open questions by studying Heinrich events in a coupled ice sheet model (ISM) atmosphere-ocean-vegetation general circulation model (AOVGCM) framework, where this variability occurs as part of the model generated internal variability. The framework consists of a northern hemisphere setup of the modified Parallel Ice Sheet Model (mPISM) coupled to the global AOVGCM ECHAM5/MPIOM/LPJ. The simulations were performed fully coupled and with transient orbital and greenhouse gas forcing. They span from several millennia before the last glacial maximum into the deglaciation. To make these long simulations feasible, the atmosphere is accelerated by a factor of 10 relative to the other model components using a periodical-synchronous coupling technique. To disentangle effects of the Heinrich events and the deglaciation, we focus on the events occurring before the deglaciation. The modeled Heinrich events show a peak ice discharge of about 0.05 Sv and raise the sea level by 2.3 m on average. The resulting surface water freshening reduces the Atlantic meridional overturning circulation and ocean heat release. The reduction in ocean heat release causes a sub-surface warming and decreases the air temperature and precipitation regionally and downstream into Eurasia. The surface elevation decrease of the ice sheet enhances moisture transport onto the ice sheet and thus increases precipitation over the Hudson Bay area, thereby accelerating the recovery after an event.

  4. Intermediate Palomar Transient Factory: Realtime Image Subtraction Pipeline

    DOE PAGES

    Cao, Yi; Nugent, Peter E.; Kasliwal, Mansi M.

    2016-09-28

    A fast-turnaround pipeline for realtime data reduction plays an essential role in discovering and permitting followup observations to young supernovae and fast-evolving transients in modern time-domain surveys. In this paper, we present the realtime image subtraction pipeline in the intermediate Palomar Transient Factory. By using highperformance computing, efficient databases, and machine-learning algorithms, this pipeline manages to reliably deliver transient candidates within 10 minutes of images being taken. Our experience in using high-performance computing resources to process big data in astronomy serves as a trailblazer to dealing with data from large-scale time-domain facilities in the near future.

  5. Intermediate Palomar Transient Factory: Realtime Image Subtraction Pipeline

    SciT

    Cao, Yi; Nugent, Peter E.; Kasliwal, Mansi M.

    A fast-turnaround pipeline for realtime data reduction plays an essential role in discovering and permitting followup observations to young supernovae and fast-evolving transients in modern time-domain surveys. In this paper, we present the realtime image subtraction pipeline in the intermediate Palomar Transient Factory. By using highperformance computing, efficient databases, and machine-learning algorithms, this pipeline manages to reliably deliver transient candidates within 10 minutes of images being taken. Our experience in using high-performance computing resources to process big data in astronomy serves as a trailblazer to dealing with data from large-scale time-domain facilities in the near future.

  6. Transient radiative energy transfer in incompressible laminar flows

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.; Singh, D. J.

    1987-01-01

    Analysis and numerical procedures are presented to investigate the transient radiative interactions of nongray absorbing-emitting species in laminar fully-developed flows between two parallel plates. The particular species considered are OH, CO, CO2, and H2O and different mixtures of these. Transient and steady-state results are obtained for the temperaure distribution and bulk temperature for different plate spacings, wall temperatures, and pressures. Results, in general, indicate that the rate of radiative heating can be quite high during earlier times. This information is useful in designing thermal protection systems for transient operations.

  7. Metabolic studies of transient tyrosinemia in premature infants

    NASA Technical Reports Server (NTRS)

    Fernbach, S. A.; Summons, R. E.; Pereira, W. E.; Duffield, A. M.

    1975-01-01

    The recently developed technique of gas chromatography-mass spectrometry supported by computer has considerably improved the analysis of physiologic fluids. This study attempted to demonstrate the value of this system in the investigation of metabolite patterns in urine in two metabolic problems of prematurity, transient tyrosinemia and late metabolic acidosis. Serial 24-hr urine specimens were analyzed in 9 infants. Transient tyrosinemia, characterized by 5- 10-fold increases over basal excretion of tyrosine, p-hydroxyphenyllactate, and p-hydroxyphenylpyruvate in urine, was noted in five of the infants. Late metabolic acidosis was seen in four infants, but bore no relation to transient tyrosinemia.

  8. Techniques for improving transients in learning control systems

    NASA Technical Reports Server (NTRS)

    Chang, C.-K.; Longman, Richard W.; Phan, Minh

    1992-01-01

    A discrete modern control formulation is used to study the nature of the transient behavior of the learning process during repetitions. Several alternative learning control schemes are developed to improve the transient performance. These include a new method using an alternating sign on the learning gain, which is very effective in limiting peak transients and also very useful in multiple-input, multiple-output systems. Other methods include learning at an increasing number of points progressing with time, or an increasing number of points of increasing density.

  9. Deconvolution of noisy transient signals: a Kalman filtering application

    SciT

    Candy, J.V.; Zicker, J.E.

    The deconvolution of transient signals from noisy measurements is a common problem occuring in various tests at Lawrence Livermore National Laboratory. The transient deconvolution problem places atypical constraints on algorithms presently available. The Schmidt-Kalman filter, a time-varying, tunable predictor, is designed using a piecewise constant model of the transient input signal. A simulation is developed to test the algorithm for various input signal bandwidths and different signal-to-noise ratios for the input and output sequences. The algorithm performance is reasonable.

  10. Real-time Recovery Efficiencies and Performance of the Palomar Transient Factory’s Transient Discovery Pipeline

    NASA Astrophysics Data System (ADS)

    Frohmaier, C.; Sullivan, M.; Nugent, P. E.; Goldstein, D. A.; DeRose, J.

    2017-05-01

    We present the transient source detection efficiencies of the Palomar Transient Factory (PTF), parameterizing the number of transients that PTF found versus the number of similar transients that occurred over the same period in the survey search area but were missed. PTF was an optical sky survey carried out with the Palomar 48 inch telescope over 2009-2012, observing more than 8000 square degrees of sky with cadences of between one and five days, locating around 50,000 non-moving transient sources, and spectroscopically confirming around 1900 supernovae. We assess the effectiveness with which PTF detected transient sources, by inserting ≃ 7 million artificial point sources into real PTF data. We then study the efficiency with which the PTF real-time pipeline recovered these sources as a function of the source magnitude, host galaxy surface brightness, and various observing conditions (using proxies for seeing, sky brightness, and transparency). The product of this study is a multi-dimensional recovery efficiency grid appropriate for the range of observing conditions that PTF experienced and that can then be used for studies of the rates, environments, and luminosity functions of different transient types using detailed Monte Carlo simulations. We illustrate the technique using the observationally well-understood class of type Ia supernovae.

  11. Transient global amnesia and transient ischemic attack. Natural history, vascular risk factors, and associated conditions.

    PubMed

    Zorzon, M; Antonutti, L; Masè, G; Biasutti, E; Vitrani, B; Cazzato, G

    1995-09-01

    The purpose of the present study was to make an attempt to ascertain the etiology of transient global amnesia (TGA), which is still disputed more than 30 years after the first description of this clinical entity. In a case-control study, we compared the prevalence of vascular risk factors in 64 TGA patients with 64 first-ever transient ischemic attack (TIA) control subjects and 108 normal community-based control subjects matched for age and sex. We prospectively studied the vascular events and mortality rates of the TGA cases and of the TIA control subjects. Then we compared the outcome of the two groups using actuarial analysis based on survival curves. We did not find evidence of an increased risk of TGA associated with any vascular risk factor. In contrast to TIA control subjects, no TGA patient suffered stroke, myocardial infarction, or TIA during the follow-up period. Migraine was more common in TGA patients than in both normal and TIA control subjects. In three patients (4.5%), the TGA was eventually considered to be of epileptic origin. The results of our case-control and longitudinal studies point to the conclusion that TGA and TIA do not share the same etiology. Since half of our patients had a precipitating event in their history, it is reasonable to hypothesize that spreading depression may play a role in TGA. The significant positive association between migraine and TGA may support this hypothesis. Epilepsy may mimic TGA in a minority of cases.

  12. A COMPARISON OF TRANSIENT INFINITE ELEMENTS AND TRANSIENT KIRCHHOFF INTEGRAL METHODS FOR FAR FIELD ACOUSTIC ANALYSIS

    DOE PAGES

    WALSH, TIMOTHY F.; JONES, ANDREA; BHARDWAJ, MANOJ; ...

    2013-04-01

    Finite element analysis of transient acoustic phenomena on unbounded exterior domains is very common in engineering analysis. In these problems there is a common need to compute the acoustic pressure at points outside of the acoustic mesh, since meshing to points of interest is impractical in many scenarios. In aeroacoustic calculations, for example, the acoustic pressure may be required at tens or hundreds of meters from the structure. In these cases, a method is needed for post-processing the acoustic results to compute the response at far-field points. In this paper, we compare two methods for computing far-field acoustic pressures, onemore » derived directly from the infinite element solution, and the other from the transient version of the Kirchhoff integral. Here, we show that the infinite element approach alleviates the large storage requirements that are typical of Kirchhoff integral and related procedures, and also does not suffer from loss of accuracy that is an inherent part of computing numerical derivatives in the Kirchhoff integral. In order to further speed up and streamline the process of computing the acoustic response at points outside of the mesh, we also address the nonlinear iterative procedure needed for locating parametric coordinates within the host infinite element of far-field points, the parallelization of the overall process, linear solver requirements, and system stability considerations.« less

  13. Kinetics of transient electroluminescence in organic light emitting diodes

    NASA Astrophysics Data System (ADS)

    Shukla, Manju; Kumar, Pankaj; Chand, Suresh; Brahme, Nameeta; Kher, R. S.; Khokhar, M. S. K.

    2008-08-01

    Mathematical simulation on the rise and decay kinetics of transient electroluminescence (EL) in organic light emitting diodes (OLEDs) is presented. The transient EL is studied with respect to a step voltage pulse. While rising, for lower values of time, the EL intensity shows a quadratic dependence on (t - tdel), where tdel is the time delay observed in the onset of EL, and finally attains saturation at a sufficiently large time. When the applied voltage is switched off, the initial EL decay shows an exponential dependence on (t - tdec), where tdec is the time when the voltage is switched off. The simulated results are compared with the transient EL performance of a bilayer OLED based on small molecular bis(2-methyl 8-hydroxyquinoline)(triphenyl siloxy) aluminium (SAlq). Transient EL studies have been carried out at different voltage pulse amplitudes. The simulated results show good agreement with experimental data. Using these simulated results the lifetime of the excitons in SAlq has also been calculated.

  14. Transient classification in LIGO data using difference boosting neural network

    NASA Astrophysics Data System (ADS)

    Mukund, N.; Abraham, S.; Kandhasamy, S.; Mitra, S.; Philip, N. S.

    2017-05-01

    Detection and classification of transients in data from gravitational wave detectors are crucial for efficient searches for true astrophysical events and identification of noise sources. We present a hybrid method for classification of short duration transients seen in gravitational wave data using both supervised and unsupervised machine learning techniques. To train the classifiers, we use the relative wavelet energy and the corresponding entropy obtained by applying one-dimensional wavelet decomposition on the data. The prediction accuracy of the trained classifier on nine simulated classes of gravitational wave transients and also LIGO's sixth science run hardware injections are reported. Targeted searches for a couple of known classes of nonastrophysical signals in the first observational run of Advanced LIGO data are also presented. The ability to accurately identify transient classes using minimal training samples makes the proposed method a useful tool for LIGO detector characterization as well as searches for short duration gravitational wave signals.

  15. Real-time detection of optical transients with RAPTOR

    SciT

    Borozdin, K. N.; Brumby, Steven P.; Galassi, M. C.

    2002-01-01

    Fast variability of optical objects is an interesting though poorly explored subject in modern astronomy. Real-time data processing and identification of transient, celestial events in the images is very important, for such study as it allows rapid follow-up with more sensitive instruments, We discuss an approach which we have chosen for the RAPTOR project which is a pioneering close-loop system combining real-time transient detection with rapid follow-up. Our data processing pipeline is able to identify and localize an optical transient within seconds after the observation. We describe the challenges we met, solutions we found and some results obtained in ourmore » search for fast optical transients. The software pipeline we have developed for RAPTOR can easily be applied to the data from other experiments.« less

  16. Apparatus and method for transient thermal infrared emission spectrometry

    DOEpatents

    McClelland, John F.; Jones, Roger W.

    1991-12-24

    A method and apparatus for enabling analysis of a solid material (16, 42) by applying energy from an energy source (20, 70) top a surface region of the solid material sufficient to cause transient heating in a thin surface layer portion of the solid material (16, 42) so as to enable transient thermal emission of infrared radiation from the thin surface layer portion, and by detecting with a spectrometer/detector (28, 58) substantially only the transient thermal emission of infrared radiation from the thin surface layer portion of the solid material. The detected transient thermal emission of infrared radiation is sufficiently free of self-absorption by the solid material of emitted infrared radiation, so as to be indicative of characteristics relating to molecular composition of the solid material.

  17. Intermittent/transient fault phenomena in digital systems

    NASA Technical Reports Server (NTRS)

    Masson, G. M.

    1977-01-01

    An overview of the intermittent/transient (IT) fault study is presented. An interval survivability evaluation of digital systems for IT faults is discussed along with a method for detecting and diagnosing IT faults in digital systems.

  18. Transient radiation in an anisotropic magnetodielectric plate in a waveguide

    NASA Astrophysics Data System (ADS)

    Gevorkyan, E. A.

    2017-02-01

    We have considered transient radiation of a charged particle in an anisotropic magnetodielectric plate placed into a regular waveguide. It is assumed that the charged particle passes through the plate moving at a constant velocity perpendicularly to the waveguide axis. Wave equations and analytical expressions for transverse electric (TE) and transverse magnetic (TM) fields in different regions of the waveguide have been obtained. Energies of transient radiation of the moving particle have been calculated. The properties of transient radiation and Vavilov-Cherenkov radiation have been analyzed for the case of a rectangular waveguide. Energies of transient radiation have been calculated for the case of a "thin" plate in the waveguide, when the wavelength in the plate is much greater than the length of the plate.

  19. Photometry and brightening of Galactic transient ASASSN-18fv

    NASA Astrophysics Data System (ADS)

    Brown, M. J. I.; Upjohn, J.; Rol, E.; Obradovic, A.; Galloway, D. K.; Ackley, K.; Davies, J.; Lane, C.; Olofsson, S.; Reader, N.

    2018-03-01

    We report follow-up B and V photometry of Galactic transient ASASSN-18fv (Stanek et al. ATEL #11454). The photometry was taken with the 14-inch telescope at Hutton-Westfold Observatory, located at Monash University's Clayton campus.

  20. Single Event Transients in Low Voltage Dropout (LVDO) Voltage Regulators

    NASA Technical Reports Server (NTRS)

    LaBel, K.; Karsh, J.; Pursley, S.; Kleyner, I.; Katz, R.; Poivey, C.; Kim, H.; Seidleck, C.

    2006-01-01

    This viewgraph presentation reviews the use of Low Voltage Dropout (LVDO) Voltage Regulators in environments where heavy ion induced Single Event Transients are a concern to the designers.Included in the presentation are results of tests of voltage regulators.

  1. A new transiently chaotic flow with ellipsoid equilibria

    NASA Astrophysics Data System (ADS)

    Panahi, Shirin; Aram, Zainab; Jafari, Sajad; Pham, Viet-Thanh; Volos, Christos; Rajagopal, Karthikeyan

    2018-03-01

    In this article, a simple autonomous transiently chaotic flow with cubic nonlinearities is proposed. This system represents some unusual features such as having a surface of equilibria. We shall describe some dynamical properties and behaviours of this system in terms of eigenvalue structures, bifurcation diagrams, time series, and phase portraits. Various behaviours of this system such as periodic and transiently chaotic dynamics can be shown by setting special parameters in proper values. Our system belongs to a newly introduced category of transiently chaotic systems: systems with hidden attractors. Transiently chaotic behaviour of our proposed system has been implemented and tested by the OrCAD-PSpise software. We have found a proper qualitative similarity between circuit and simulation results.

  2. INDUCIBLE TRANSIENT CENTRAL RETINAL ARTERY VASOSPASM: A CASE REPORT.

    PubMed

    Mishulin, Aleksey; Ghandi, Sachin; Apple, Daniel; Lin, Xihui; Hu, Jonathan; Abrams, Gary W

    2017-09-27

    To report a case of inducible transient central retinal artery vasospasm with associated imaging. Observational case report. A 51-year-old man presented for outpatient follow-up for recurrent inducible transient vision loss in his right eye. He experienced an episode during examination and was found to have central retinal artery vasospasm. Fundus photography and fluorescein angiography obtained during his vasospastic attack confirmed retinal arterial vasospasm. Treatment with a calcium-channel blocker (nifedipine) has been effective in preventing recurrent attacks. Idiopathic primary vasospasm is a rare cause of transient vision loss that is difficult to confirm because of the transient nature. We obtained imaging showing the initiation and resolution of the vasospastic event. The patient was then successfully treated with a calcium-channel blocker.

  3. Spectroscopic Classifications of Optical Transients with the Lick Shane telescope

    NASA Astrophysics Data System (ADS)

    Rojas-Bravo, C.; Xhakaj, E.; Pan, Y.-C.; Kilpatrick, C. D.; Foley, R. J.

    2017-07-01

    We report the following classifications of optical transients from spectroscopic observations with the Kast spectrograph on the Shane telescope. Targets were supplied by ASAS-SN, ATLAS, Gaia, and POSS.

  4. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Kilpatrick, C. D.; Siebert, M. R.; Foley, R. J.; Pan, Y.-C.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-08-01

    We report the following classifications of optical transients from spectroscopic observations with KOSMOS on the KPNO Mayall 4-m telescope. Targets were supplied by Shunsuke Nagata, POSS, and ASAS-SN.

  5. Adaptive Nodal Transport Methods for Reactor Transient Analysis

    SciT

    Thomas Downar; E. Lewis

    2005-08-31

    Develop methods for adaptively treating the angular, spatial, and time dependence of the neutron flux in reactor transient analysis. These methods were demonstrated in the DOE transport nodal code VARIANT and the US NRC spatial kinetics code, PARCS.

  6. Radio and white-light observations of coronal transients

    NASA Technical Reports Server (NTRS)

    Dulk, G. A.

    1980-01-01

    Optical, radio and X-ray evidence of violent mass motions in the corona has existed for some years but only recently have the form, nature, frequency and implication of the transients become obvious. In this paper the observed properties of coronal transients are reviewed, with concentration on the white-light and radio manifestations. The classification according to speeds seems to be meaningful, with the slow transients having thermal emissions at radio wavelengths and the fast ones nonthermal. The possible mechanisms involved in the radio bursts are then discussed and estimates of various forms of energy are reviewed. It appears that the magnetic energy transported from the sun by the transient exceeds that of any other form, and that magnetic forces dominate in the dynamics of the motions. The conversion of magnetic energy into mechanical energy, by expansion of the field, provides a possible driving force for the coronal and interplanetary shock waves.

  7. Surface radiation fluxes in transient climate simulations

    NASA Astrophysics Data System (ADS)

    Garratt, J. R.; O'Brien, D. M.; Dix, M. R.; Murphy, J. M.; Stephens, G. L.; Wild, M.

    1999-01-01

    Transient CO 2 experiments from five coupled climate models, in which the CO 2 concentration increases at rates of 0.6-1.1% per annum for periods of 75-200 years, are used to document the responses of surface radiation fluxes, and associated atmospheric properties, to the CO 2 increase. In all five models, the responses of global surface temperature and column water vapour are non-linear and fairly tightly constrained. Thus, global warming lies between 1.9 and 2.7 K at doubled, and between 3.1 and 4.1 K at tripled, CO 2, whilst column water vapour increases by between 3.5 and 4.5 mm at doubled, and between 7 and 8 mm at tripled, CO 2. Global cloud fraction tends to decrease by 1-2% out to tripled CO 2, mainly the result of decreases in low cloud. Global increases in column water, and differences in these increases between models, are mainly determined by the warming of the tropical oceans relative to the middle and high latitudes; these links are emphasised in the zonal profiles of warming and column water vapour increase, with strong water vapour maxima in the tropics. In all models the all-sky shortwave flux to the surface S↓ (global, annual average) changes by less than 5 W m -2 out to tripled CO 2, in some cases being essentially invariant in time. In contrast, the longwave flux to the surface L↓ increases significantly, by 25 W m -2 typically at tripled CO 2. The variations of S↓ and L↓ (clear-sky and all-sky fluxes) with increase in CO 2 concentration are generally non-linear, reflecting the effects of ocean thermal inertia, but as functions of global warming are close to linear in all five models. This is best illustrated for the clear-sky downwelling fluxes, and the net radiation. Regionally, as illustrated in zonal profiles and global distributions, greatest changes in both S↓ and L↓ are the result primarily of local maxima in warming and column water vapour increases.

  8. Transient neutropenia: Neutrophil distribution and replacement

    SciT

    Thakur, M.L.; Li, Jinghua; Binoy, Li

    Radiolabeled polymorphonuclear (PMN) receptor-specific proteins or peptides lead the list of agents being evaluated for imaging inflammatory foci. Some of these agents induce transient neutropenia. This study was designed to quantify the degree of dose dependency of neutropenia, determine the duration of neutropenia, identify the organs in which these PMNs sequester and ascertain if these PMNs return to the circulation. Rodent anti-PMN (Gr-1) MAb RB6-8C5 (lgG-2A) and Balb/c mice served as the model, and PMN nonspecific ME 31.3 (lgG-2A) as a control. Circulating PMN number was determined several times, 30 min prior to and between 1 min and 120 hrmore » after MAb administration. Iodine-125-MAbs provided quantification of circulating activity and tissue distribution as a function of time. Data showed the severity of neutropenia increased with the amount of MAb administered (>95% PMNs lost after 150 {mu}g versus <85% after 10 {mu}g). Moreover, the recovery time for PMN counts to reach the pretreatment level also increased in a dose-dependent manner (96 hr at 150 {mu}g versus 4 hr at 10 {mu}g and 2 hr at 2 {mu}g). The blood activity, however, which declined quickly with the neutropenia, never rose again with PMN recovery. As a function of time, radioactivity in the study group decreased from all organs except from the liver and spleen, whereas in the control group; and spleen, 15.5% decrease versus 63.6% decrease in control group. The degree and duration of neutropenia is dose-dependent. PMNs, lost from the circulation, sequester in the reticuloendothelial system, and do not return to circulation. Therefore, they are not available to image inflammatory foci. The PMN concentration is restored to a pretreatment level in a dose-dependent fashion, presumably by freshly released PMNs from bone marrow. 32 refs., 5 figs.« less

  9. Hydrological controls on transient aquifer storage in a karst watershed

    NASA Astrophysics Data System (ADS)

    Spellman, P.; Martin, J.; Gulley, J. D.

    2017-12-01

    While surface storage of floodwaters is well-known to attenuate flood peaks, transient storage of floodwaters in aquifers is a less recognized mechanism of flood peak attenuation. The hydraulic gradient from aquifer to river controls the magnitude of transient aquifer storage and is ultimately a function of aquifer hydraulic conductivity, and effective porosity. Because bedrock and granular aquifers tend to have lower hydraulic conductivities and porosities, their ability to attenuate flood peaks is generally small. In karst aquifers, however, extensive cave systems create high hydraulic conductivities and porosities that create low antecedent hydraulic gradients between aquifers and rivers. Cave springs can reverse flow during high discharges in rivers, temporarily storing floodwaters in the aquifer thus reducing the magnitude of flood discharge downstream. To date however, very few studies have quantified the magnitude or controls of transient aquifer storage in karst watersheds. We therefore investigate controls on transient aquifer storage by using 10 years of river and groundwater data from the Suwannee River Basin, which flows over the karstic upper Floridan aquifer in north-central Florida. We use multiple linear regression to compare the effects of three hydrological controls on the magnitude of transient aquifer storage: antecedent stage, recharge and slope of hydrograph rise. We show the dominant control on transient aquifer storage is antecedent stage, whereby lower stages result in greater magnitudes of transient aquifer storage. Our results suggest that measures of groundwater levels prior to an event can be useful in determining whether transient aquifer storage will occur and may provide a useful metric for improving predictions of flood magnitudes.

  10. 47 CFR 90.214 - Transient frequency behavior.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Transient frequency behavior. 90.214 Section 90... PRIVATE LAND MOBILE RADIO SERVICES General Technical Standards § 90.214 Transient frequency behavior... Behavior for Equipment Designed to Operate on 25 kHz Channels t1 4 ±25.0 kHz 5.0 ms 10.0 ms t2 ±12.5 kHz 20...

  11. 47 CFR 90.214 - Transient frequency behavior.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Transient frequency behavior. 90.214 Section 90... PRIVATE LAND MOBILE RADIO SERVICES General Technical Standards § 90.214 Transient frequency behavior... Behavior for Equipment Designed to Operate on 25 kHz Channels t1 4 ±25.0 kHz 5.0 ms 10.0 ms t2 ±12.5 kHz 20...

  12. 47 CFR 90.214 - Transient frequency behavior.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Transient frequency behavior. 90.214 Section 90... PRIVATE LAND MOBILE RADIO SERVICES General Technical Standards § 90.214 Transient frequency behavior... Behavior for Equipment Designed to Operate on 25 kHz Channels t1 4 ±25.0 kHz 5.0 ms 10.0 ms t2 ±12.5 kHz 20...

  13. 47 CFR 90.214 - Transient frequency behavior.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Transient frequency behavior. 90.214 Section 90... PRIVATE LAND MOBILE RADIO SERVICES General Technical Standards § 90.214 Transient frequency behavior... Behavior for Equipment Designed to Operate on 25 kHz Channels t1 4 ±25.0 kHz 5.0 ms 10.0 ms t2 ±12.5 kHz 20...

  14. Lifetime Reliability Prediction of Ceramic Structures Under Transient Thermomechanical Loads

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Jadaan, Osama J.; Gyekenyesi, John P.

    2005-01-01

    An analytical methodology is developed to predict the probability of survival (reliability) of ceramic components subjected to harsh thermomechanical loads that can vary with time (transient reliability analysis). This capability enables more accurate prediction of ceramic component integrity against fracture in situations such as turbine startup and shutdown, operational vibrations, atmospheric reentry, or other rapid heating or cooling situations (thermal shock). The transient reliability analysis methodology developed herein incorporates the following features: fast-fracture transient analysis (reliability analysis without slow crack growth, SCG); transient analysis with SCG (reliability analysis with time-dependent damage due to SCG); a computationally efficient algorithm to compute the reliability for components subjected to repeated transient loading (block loading); cyclic fatigue modeling using a combined SCG and Walker fatigue law; proof testing for transient loads; and Weibull and fatigue parameters that are allowed to vary with temperature or time. Component-to-component variation in strength (stochastic strength response) is accounted for with the Weibull distribution, and either the principle of independent action or the Batdorf theory is used to predict the effect of multiaxial stresses on reliability. The reliability analysis can be performed either as a function of the component surface (for surface-distributed flaws) or component volume (for volume-distributed flaws). The transient reliability analysis capability has been added to the NASA CARES/ Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code. CARES/Life was also updated to interface with commercially available finite element analysis software, such as ANSYS, when used to model the effects of transient load histories. Examples are provided to demonstrate the features of the methodology as implemented in the CARES/Life program.

  15. The mechanism of transient myopia induced by sulfonamide therapy.

    PubMed

    Bovino, J A; Marcus, D F

    1982-07-01

    We performed acute and convalescent A-scan echographic ocular measurements documenting the anterior chamber depth, lens thickness, and axial length of a patient with acute transient sulfamethoxazole-induced myopia. Shallowing of the anterior chamber, independent of changes in the thickness of the lens, was the only anatomic variation found that could explain the myopia. Swelling of the ciliary body, with forward movement of the lens-iris diaphragm, could produce this transient anatomic change.

  16. OGLE-IV Real-Time Transient Search

    NASA Astrophysics Data System (ADS)

    Wyrzykowski, Ł.; Kostrzewa-Rutkowska, Z.; Kozłowski, S.; Udalski, A.; Poleski, R.; Skowron, J.; Blagorodnova, N.; Kubiak, M.; Szymański, M. K.; Pietrzyński, G.; Soszyński, I.; Ulaczyk, K.; Pietrukowicz, P.; Mróz, P.

    2014-09-01

    We present the design and first results of a real-time search for transients within the 650 sq. deg. area around the Magellanic Clouds, conducted as part of the OGLE-IV project and aimed at detecting supernovae, novae and other events. The average sampling of about four days from September to May, yielded a detection of 238 transients in 2012/2013 and 2013/2014 seasons. The superb photometric and astrometric quality of the OGLE data allows for numerous applications of the discovered transients. We use this sample to prepare and train a Machine Learning-based automated classifier for early light curves, which distinguishes major classes of transients with more than 80% of correct answers. Spectroscopically classified 49 supernovae Type Ia are used to construct a Hubble Diagram with statistical scatter of about 0.3 mag and fill the least populated region of the redshifts range in the Union sample. We investigate the influence of host galaxy environments on supernovae statistics and find the mean host extinction of AI=0.19±0.10 mag and AV=0.39±0.21 mag based on a subsample of supernovae Type Ia. We show that the positional accuracy of the survey is of the order of 0.5 pixels (0.13'') and that the OGLE-IV Transient Detection System is capable of detecting transients within the nuclei of galaxies. We present a few interesting cases of nuclear transients of unknown type. All data on the OGLE transients are made publicly available to the astronomical community via the OGLE website.

  17. Understanding Epileptiform After-Discharges as Rhythmic Oscillatory Transients.

    PubMed

    Baier, Gerold; Taylor, Peter N; Wang, Yujiang

    2017-01-01

    Electro-cortical activity in patients with epilepsy may show abnormal rhythmic transients in response to stimulation. Even when using the same stimulation parameters in the same patient, wide variability in the duration of transient response has been reported. These transients have long been considered important for the mapping of the excitability levels in the epileptic brain but their dynamic mechanism is still not well understood. To investigate the occurrence of abnormal transients dynamically, we use a thalamo-cortical neural population model of epileptic spike-wave activity and study the interaction between slow and fast subsystems. In a reduced version of the thalamo-cortical model, slow wave oscillations arise from a fold of cycles (FoC) bifurcation. This marks the onset of a region of bistability between a high amplitude oscillatory rhythm and the background state. In vicinity of the bistability in parameter space, the model has excitable dynamics, showing prolonged rhythmic transients in response to suprathreshold pulse stimulation. We analyse the state space geometry of the bistable and excitable states, and find that the rhythmic transient arises when the impending FoC bifurcation deforms the state space and creates an area of locally reduced attraction to the fixed point. This area essentially allows trajectories to dwell there before escaping to the stable steady state, thus creating rhythmic transients. In the full thalamo-cortical model, we find a similar FoC bifurcation structure. Based on the analysis, we propose an explanation of why stimulation induced epileptiform activity may vary between trials, and predict how the variability could be related to ongoing oscillatory background activity. We compare our dynamic mechanism with other mechanisms (such as a slow parameter change) to generate excitable transients, and we discuss the proposed excitability mechanism in the context of stimulation responses in the epileptic cortex.

  18. OGLE-IV Transient Search summary of season 2015b

    NASA Astrophysics Data System (ADS)

    Wyrzykowski, L.; Kostrzewa-Rutkowska, Z.; Klencki, J.; Sitek, M.; Mroz, P.; Udalski, A.; Kozlowski, S.; Skowron, J.; Poleski, R.; Szymanski, M. K.; Pietrzynski, G.; Soszynski, I.; Ulaczyk, K.; Pietrukowicz, P.

    2015-12-01

    The OGLE-IV Transient Detection System (Wyrzykowski et al. 2014, AcA,64,197; Kozlowski et al. 2013) in the 2015b transient observing season (from August) has been operating in dual mode: regular as in previous years (detections every couple of days based on at least two positive detections), and rapid (automatised detections within 15 mins after the single frame was taken, details in Klencki et al. in prep.).

  19. Schumann resonance transients and the search for gravitational waves

    NASA Astrophysics Data System (ADS)

    Silagadze, Z. K.

    2018-02-01

    Schumann resonance transients which propagate around the globe can potentially generate a correlated background in widely separated gravitational-wave detectors. We show that due to the distribution of lightning hotspots around the globe, these transients have characteristic time lags, and this feature can be useful to further suppress such a background, especially in searches of the stochastic gravitational-wave background. A brief review of the corresponding literature on Schumann resonances and lightnings is also given.

  20. Novel Material Systems and Methodologies for Transient Thermal Management

    NASA Technical Reports Server (NTRS)

    Oliva-Buisson, Yvette J.

    2014-01-01

    Development of multifunctional and thermally switchable systems to address reduced mass and components, and tailored for both structural and transient thermal applications. Active, passive, and novel combinations of the two functional approaches are being developed along two lines of research investigation: switchable systems and transient heat spreading. The approach is to build in thermal functionality to structural elements to lay the foundation for a revolution in the way high energy space systems are designed.

  1. Acoustic transient generation in pulsed holmium laser ablation under water

    NASA Astrophysics Data System (ADS)

    Asshauer, Thomas; Rink, Klaus; Delacretaz, Guy P.; Salathe, Rene-Paul; Gerber, Bruno E.; Frenz, Martin; Pratisto, Hans; Ith, Michael; Romano, Valerio; Weber, Heinz P.

    1994-08-01

    In this study the role of acoustical transients during pulsed holmium laser ablation is addressed. For this the collapse of cavitation bubbles generated by 2.12 micrometers Cr:Tm:Ho:YAG laser pulses delivered via a fiber in water is investigated. Multiple consecutive collapses of a single bubble generating acoustic transients are documented. Pulse durations are varied from 130 - 230 microsecond(s) and pulse energies from 20 - 800 mJ. Fiber diameters of 400 and 600 micrometers are used. The bubble collapse behavior is observed by time resolved fast flash photography with 1 microsecond(s) strobe lamp or 5 ns 1064 nm Nd:YAG laser illumination. A PVDF needle probe transducer is used to observe acoustic transients and measure their pressure amplitudes. Under certain conditions, at the end of the collapse phase the bubbles emit spherical acoustic transients of up to several hundred bars amplitude. After the first collapse up to two rebounds leading to further acoustic transient emissions are observed. Bubbles generated near a solid surface under water are attracted towards the surface during their development. The final phase of the collapse generating the acoustic transients takes place directly on the surface, exposing it to maximum pressure amplitudes. Our results indicate a possible mechanism of unwanted tissue damage during holmium laser application in a liquid environment as in arthroscopy or angioplasty that may set limits to the choice of laser pulse duration and energies.

  2. Two peculiar fast transients in a strongly lensed host galaxy

    NASA Astrophysics Data System (ADS)

    Rodney, S. A.; Balestra, I.; Bradac, M.; Brammer, G.; Broadhurst, T.; Caminha, G. B.; Chirivı, G.; Diego, J. M.; Filippenko, A. V.; Foley, R. J.; Graur, O.; Grillo, C.; Hemmati, S.; Hjorth, J.; Hoag, A.; Jauzac, M.; Jha, S. W.; Kawamata, R.; Kelly, P. L.; McCully, C.; Mobasher, B.; Molino, A.; Oguri, M.; Richard, J.; Riess, A. G.; Rosati, P.; Schmidt, K. B.; Selsing, J.; Sharon, K.; Strolger, L.-G.; Suyu, S. H.; Treu, T.; Weiner, B. J.; Williams, L. L. R.; Zitrin, A.

    2018-04-01

    A massive galaxy cluster can serve as a magnifying glass for distant stellar populations, as strong gravitational lensing magnifies background galaxies and exposes details that are otherwise undetectable. In time-domain astronomy, imaging programmes with a short cadence are able to detect rapidly evolving transients, previously unseen by surveys designed for slowly evolving supernovae. Here, we describe two unusual transient events discovered in a Hubble Space Telescope programme that combined these techniques with high-cadence imaging on a field with a strong-lensing galaxy cluster. These transients were faster and fainter than any supernovae, but substantially more luminous than a classical nova. We find that they can be explained as separate eruptions of a luminous blue variable star or a recurrent nova, or as an unrelated pair of stellar microlensing events. To distinguish between these hypotheses will require clarification of the cluster lens models, along with more high-cadence imaging of the field that could detect related transient episodes. This discovery suggests that the intersection of strong lensing with high-cadence transient surveys may be a fruitful path for future astrophysical transient studies.

  3. Power System Transient Stability Based on Data Mining Theory

    NASA Astrophysics Data System (ADS)

    Cui, Zhen; Shi, Jia; Wu, Runsheng; Lu, Dan; Cui, Mingde

    2018-01-01

    In order to study the stability of power system, a power system transient stability based on data mining theory is designed. By introducing association rules analysis in data mining theory, an association classification method for transient stability assessment is presented. A mathematical model of transient stability assessment based on data mining technology is established. Meanwhile, combining rule reasoning with classification prediction, the method of association classification is proposed to perform transient stability assessment. The transient stability index is used to identify the samples that cannot be correctly classified in association classification. Then, according to the critical stability of each sample, the time domain simulation method is used to determine the state, so as to ensure the accuracy of the final results. The results show that this stability assessment system can improve the speed of operation under the premise that the analysis result is completely correct, and the improved algorithm can find out the inherent relation between the change of power system operation mode and the change of transient stability degree.

  4. Mary, a Pipeline to Aid Discovery of Optical Transients

    NASA Astrophysics Data System (ADS)

    Andreoni, I.; Jacobs, C.; Hegarty, S.; Pritchard, T.; Cooke, J.; Ryder, S.

    2017-09-01

    The ability to quickly detect transient sources in optical images and trigger multi-wavelength follow up is key for the discovery of fast transients. These include events rare and difficult to detect such as kilonovae, supernova shock breakout, and `orphan' Gamma-ray Burst afterglows. We present the Mary pipeline, a (mostly) automated tool to discover transients during high-cadenced observations with the Dark Energy Camera at Cerro Tololo Inter-American Observatory (CTIO). The observations are part of the `Deeper Wider Faster' programme, a multi-facility, multi-wavelength programme designed to discover fast transients, including counterparts to Fast Radio Bursts and gravitational waves. Our tests of the Mary pipeline on Dark Energy Camera images return a false positive rate of 2.2% and a missed fraction of 3.4% obtained in less than 2 min, which proves the pipeline to be suitable for rapid and high-quality transient searches. The pipeline can be adapted to search for transients in data obtained with imagers other than Dark Energy Camera.

  5. Analytical Assessment for Transient Stability Under Stochastic Continuous Disturbances

    SciT

    Ju, Ping; Li, Hongyu; Gan, Chun

    Here, with the growing integration of renewable power generation, plug-in electric vehicles, and other sources of uncertainty, increasing stochastic continuous disturbances are brought to power systems. The impact of stochastic continuous disturbances on power system transient stability attracts significant attention. To address this problem, this paper proposes an analytical assessment method for transient stability of multi-machine power systems under stochastic continuous disturbances. In the proposed method, a probability measure of transient stability is presented and analytically solved by stochastic averaging. Compared with the conventional method (Monte Carlo simulation), the proposed method is many orders of magnitude faster, which makes itmore » very attractive in practice when many plans for transient stability must be compared or when transient stability must be analyzed quickly. Also, it is found that the evolution of system energy over time is almost a simple diffusion process by the proposed method, which explains the impact mechanism of stochastic continuous disturbances on transient stability in theory.« less

  6. Automated transient detection in the STEREO Heliospheric Imagers.

    NASA Astrophysics Data System (ADS)

    Barnard, Luke; Scott, Chris; Owens, Mat; Lockwood, Mike; Tucker-Hood, Kim; Davies, Jackie

    2014-05-01

    Since the launch of the twin STEREO satellites, the heliospheric imagers (HI) have been used, with good results, in tracking transients of solar origin, such as Coronal Mass Ejections (CMEs), out far into the heliosphere. A frequently used approach is to build a "J-map", in which multiple elongation profiles along a constant position angle are stacked in time, building an image in which radially propagating transients form curved tracks in the J-map. From this the time-elongation profile of a solar transient can be manually identified. This is a time consuming and laborious process, and the results are subjective, depending on the skill and expertise of the investigator. Therefore, it is desirable to develop an automated algorithm for the detection and tracking of the transient features observed in HI data. This is to some extent previously covered ground, as similar problems have been encountered in the analysis of coronagraph data and have led to the development of products such as CACtus etc. We present the results of our investigation into the automated detection of solar transients observed in J-maps formed from HI data. We use edge and line detection methods to identify transients in the J-maps, and then use kinematic models of the solar transient propagation (such as the fixed-phi and harmonic mean geometric models) to estimate the solar transients properties, such as transient speed and propagation direction, from the time-elongation profile. The effectiveness of this process is assessed by comparison of our results with a set of manually identified CMEs, extracted and analysed by the Solar Storm Watch Project. Solar Storm Watch is a citizen science project in which solar transients are identified in J-maps formed from HI data and tracked multiple times by different users. This allows the calculation of a consensus time-elongation profile for each event, and therefore does not suffer from the potential subjectivity of an individual researcher tracking an

  7. Multiwavelength Studies of Rotating Radio Transients

    NASA Astrophysics Data System (ADS)

    Miller, Joshua J.

    Seven years ago, a new class of pulsars called the Rotating Radio Transients (RRATs) was discovered with the Parkes radio telescope in Australia (McLaughlin et al., 2006). These neutron stars are characterized by strong radio bursts at repeatable dispersion measures, but not detectable using standard periodicity-search algorithms. We now know of roughly 100 of these objects, discovered in new surveys and re-analysis of archival survey data. They generally have longer periods than those of the normal pulsar population, and several have high magnetic fields, similar to those other neutron star populations like the X-ray bright magnetars. However, some of the RRATs have spin-down properties very similar to those of normal pulsars, making it difficult to determine the cause of their unusual emission and possible evolutionary relationships between them and other classes of neutron stars. We have calculated single-pulse flux densities for eight RRAT sources observed using the Parkes radio telescope. Like normal pulsars, the pulse amplitude distributions are well described by log-normal probability distribution functions, though two show evidence for an additional power-law tail. Spectral indices are calculated for the seven RRATs which were detected at multiple frequencies. These RRATs have a mean spectral index of = -3.2(7), or = -3.1(1) when using mean flux densities derived from fitting log-normal probability distribution functions to the pulse amplitude distributions, suggesting that the RRATs have steeper spectra than normal pulsars. When only considering the three RRATs for which we have a wide range of observing frequencies, however, and become --1.7(1) and --2.0(1), respectively, and are roughly consistent with those measured for normal pulsars. In all cases, these spectral indices exclude magnetar-like flat spectra. For PSR J1819--1458, the RRAT with the highest bursting rate, pulses were detected at 685 and 3029

  8. Intracochlear pressure transients during cochlear implant electrode insertion

    PubMed Central

    Greene, Nathaniel T.; Mattingly, Jameson K.; Banakis Hartl, Renee M.; Tollin, Daniel J.; Cass, Stephen P.

    2016-01-01

    Hypothesis Cochlear implant (CI) electrode insertion into the round window induces pressure transients in the cochlear fluid comparable to high intensity sound transients. Background Many patients receiving a CI have some remaining functional hearing at low frequencies, thus devices and surgical techniques have been developed to utilize this residual hearing. To maintain functional acoustic hearing, it is important to retain function of any hair cells and auditory nerve fibers innervating the basilar membrane; however, in a subset of patients, residual low frequency hearing is lost following CI insertion. Here, we test the hypothesis that transient intracochlear pressure spikes are generated during CI electrode insertion, which could cause damage and compromise residual hearing. Methods Human cadaveric temporal bones were prepared with an extended facial recess. Pressures in the scala vestibuli (PSV) and tympani (PST) were measured with fiber-optic pressure sensors inserted into the cochlea near the oval and round windows while CI electrodes (five styles from two manufacturers) were inserted into the cochlea via a round window approach. Results PST tended to be larger in magnitude than PSV, consistent with electrode insertion into the scala tympani. CI electrode insertion produced a range of pressure transients in the cochlea that could occur alone or as part of a train of spikes with equivalent peak sound pressure levels in excess of 170dB SPL. Instances of pressure transients varied with electrode styles. Conclusions Results suggest electrode design, insertion mechanism, and surgical technique affect the magnitude and rate of intracochlear pressure transients during CI electrode insertion. Pressure transients showed intensities similar to those elicited by high level sounds and thus could cause damage to the basilar membrane and/or hair cells. PMID:27753703

  9. An ultrasound transient elastography system with coded excitation.

    PubMed

    Diao, Xianfen; Zhu, Jing; He, Xiaonian; Chen, Xin; Zhang, Xinyu; Chen, Siping; Liu, Weixiang

    2017-06-28

    Ultrasound transient elastography technology has found its place in elastography because it is safe and easy to operate. However, it's application in deep tissue is limited. The aim of this study is to design an ultrasound transient elastography system with coded excitation to obtain greater detection depth. The ultrasound transient elastography system requires tissue vibration to be strictly synchronous with ultrasound detection. Therefore, an ultrasound transient elastography system with coded excitation was designed. A central component of this transient elastography system was an arbitrary waveform generator with multi-channel signals output function. This arbitrary waveform generator was used to produce the tissue vibration signal, the ultrasound detection signal and the synchronous triggering signal of the radio frequency data acquisition system. The arbitrary waveform generator can produce different forms of vibration waveform to induce different shear wave propagation in the tissue. Moreover, it can achieve either traditional pulse-echo detection or a phase-modulated or a frequency-modulated coded excitation. A 7-chip Barker code and traditional pulse-echo detection were programmed on the designed ultrasound transient elastography system to detect the shear wave in the phantom excited by the mechanical vibrator. Then an elasticity QA phantom and sixteen in vitro rat livers were used for performance evaluation of the two detection pulses. The elasticity QA phantom's results show that our system is effective, and the rat liver results show the detection depth can be increased more than 1 cm. In addition, the SNR (signal-to-noise ratio) is increased by 15 dB using the 7-chip Barker coded excitation. Applying 7-chip Barker coded excitation technique to the ultrasound transient elastography can increase the detection depth and SNR. Using coded excitation technology to assess the human liver, especially in obese patients, may be a good choice.

  10. Association of transient hyperthyroidism and severity of hyperemesis gravidarum.

    PubMed

    Malek, Nor Zila Hassan; Kalok, Aida; Hanafiah, Zainal Abidin; Shah, Shamsul Azhar; Ismail, Nor Azlin Mohamed

    2017-03-23

    Background Transient non-immune hyperthyroidism in early pregnancy is hyperthyroidism diagnosed for the first time in early pregnancy, without evidence of thyroid autoimmunity or clinical findings of Grave's disease and resolved spontaneously as the pregnancy progressed. Hyperemesis gravidarum (HG) is the commonest cause with 66%-73% of women with severe HG were found to have elevated thyroid function. Materials and methods We conducted a cross sectional study to determine the prevalence of transient hyperthyroidism in patients with hyperemesis gravidarum and its relation to the severity of nausea and vomiting. Severity of nausea and vomiting in pregnancy was assessed using the modified pregnancy-unique quantification of emesis (PUQE) scoring system. Each patient had urine and blood investigations which also included a full blood count and thyroid and renal function tests. Patients with abnormal thyroid function were retested at 20 weeks of gestation. The patients' demographic data, electrolyte levels, thyroid function and their respective PUQE score were analyzed. Results The prevalence of transient hyperthyroidism in women with hyperemesis gravidarum was 4.8%. Although there was a significant association between the severity of the PUQE score and hypokalemia (p = 0.001), there was no significant association with transient hyperthyroidism in early pregnancy (p = 0.072). Free T4 and TSH values of all women with transient hyperthyroidism were normalized by 20 weeks of gestation. Conclusion Transient hyperthyroidism in pregnancy is not significantly associated with the severity of the PUQE score. Women with transient hyperthyroidism in pregnancy are normally clinically euthyroid, hence a routine thyroid function test is unnecessary unless they exhibit clinical signs or symptoms of hyperthyroidism.

  11. Intracochlear Pressure Transients During Cochlear Implant Electrode Insertion.

    PubMed

    Greene, Nathaniel T; Mattingly, Jameson K; Banakis Hartl, Renee M; Tollin, Daniel J; Cass, Stephen P

    2016-12-01

    Cochlear implant (CI) electrode insertion into the round window induces pressure transients in the cochlear fluid comparable to high-intensity sound transients. Many patients receiving a CI have some remaining functional hearing at low frequencies; thus, devices and surgical techniques have been developed to use this residual hearing. To maintain functional acoustic hearing, it is important to retain function of any hair cells and auditory nerve fibers innervating the basilar membrane; however, in a subset of patients, residual low-frequency hearing is lost after CI insertion. Here, we test the hypothesis that transient intracochlear pressure spikes are generated during CI electrode insertion, which could cause damage and compromise residual hearing. Human cadaveric temporal bones were prepared with an extended facial recess. Pressures in the scala vestibuli and tympani were measured with fiber-optic pressure sensors inserted into the cochlea near the oval and round windows, whereas CI electrodes (five styles from two manufacturers) were inserted into the cochlea via a round window approach. Pressures in the scala tympani tended to be larger in magnitude than pressures in the scala vestibuli, consistent with electrode insertion into the scala tympani. CI electrode insertion produced a range of pressure transients in the cochlea that could occur alone or as part of a train of spikes with equivalent peak sound pressure levels in excess of 170 dB sound pressure level. Instances of pressure transients varied with electrode styles. Results suggest electrode design, insertion mechanism, and surgical technique affect the magnitude and rate of intracochlear pressure transients during CI electrode insertion. Pressure transients showed intensities similar to those elicited by high-level sounds and thus could cause damage to the basilar membrane and/or hair cells.

  12. TREAT Transient Analysis Benchmarking for the HEU Core

    SciT

    Kontogeorgakos, D. C.; Connaway, H. M.; Wright, A. E.

    2014-05-01

    This work was performed to support the feasibility study on the potential conversion of the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory from the use of high enriched uranium (HEU) fuel to the use of low enriched uranium (LEU) fuel. The analyses were performed by the GTRI Reactor Conversion staff at the Argonne National Laboratory (ANL). The objective of this study was to benchmark the transient calculations against temperature-limited transients performed in the final operating HEU TREAT core configuration. The MCNP code was used to evaluate steady-state neutronics behavior, and the point kinetics code TREKIN was used tomore » determine core power and energy during transients. The first part of the benchmarking process was to calculate with MCNP all the neutronic parameters required by TREKIN to simulate the transients: the transient rod-bank worth, the prompt neutron generation lifetime, the temperature reactivity feedback as a function of total core energy, and the core-average temperature and peak temperature as a functions of total core energy. The results of these calculations were compared against measurements or against reported values as documented in the available TREAT reports. The heating of the fuel was simulated as an adiabatic process. The reported values were extracted from ANL reports, intra-laboratory memos and experiment logsheets and in some cases it was not clear if the values were based on measurements, on calculations or a combination of both. Therefore, it was decided to use the term “reported” values when referring to such data. The methods and results from the HEU core transient analyses will be used for the potential LEU core configurations to predict the converted (LEU) core’s performance.« less

  13. Robustness of hydrological indicators for transient and stabilized climate states

    NASA Astrophysics Data System (ADS)

    Boulange, J. E.; Hanasaki, N.

    2017-12-01

    By signing the Paris agreement, countries have committed to pursue efforts to limit global warming to +1.5 °C relative to pre-industrial levels. Consequently, there is a growing interest in better understanding the impacts of a +1.5°C world. Previous analyses were conducted by considering a time slice period, centered on the year when the global mean temperature (GMT) crosses the +1.5°C threshold (Fig. 1). This time slice period is characterized by a transient state which may influence the reported results (transient climate state). Ideally, analyses should be carried under the condition the GMT is stabilized at +1.5°C (stabilized climate state) but, such targeted simulations do not exist for most GCMs.1A global hydrological model, the H08 model,2 and hydrological indicators (HI) obtained for the transient and stabilized states, are used to answer the following questions: (1) are there quantifiable differences between the HI computed for the transient and stabilized states? (2) can relations be derived between the HI computed for the transient and stabilized states? (3) what are the potential impacts induced by the differences in HI computed for the transient and stabilized states? Signal to noise ratios (S/N) obtained for the transient and stabilized states, in an identical warmer world (+1.7°C), are compared (Fig. 2). The S/N ratio computed for the stabilized state were significantly lower than those of the transient state for most regions and HI. However, at higher latitude, the S/N ratios computed for the two states were similar whereas for medium and low latitudes, the differences were more pronounced. For most regions and HI (except for surface temperature), the S/N ratios of the stabilized state were 10 to 20% weaker than those of the transient state. References:1 Knutti, R., Rogelj, J., Sedlacek, J. & Fischer, E. M. Nature Geosci (2016). 2 Hanasaki, N. et al. Hydrol. Earth Syst. Sci. (2008).

  14. VO2 Off Transient Kinetics in Extreme Intensity Swimming.

    PubMed

    Sousa, Ana; Figueiredo, Pedro; Keskinen, Kari L; Rodríguez, Ferran A; Machado, Leandro; Vilas-Boas, João P; Fernandes, Ricardo J

    2011-01-01

    Inconsistencies about dynamic asymmetry between the on- and off- transient responses in oxygen uptake are found in the literature. Therefore, the purpose of this study was to characterize the oxygen uptake off-transient kinetics during a maximal 200-m front crawl effort, as examining the degree to which the on/off regularity of the oxygen uptake kinetics response was preserved. Eight high level male swimmers performed a 200-m front crawl at maximal speed during which oxygen uptake was directly measured through breath-by-breath oxymetry (averaged every 5 s). This apparatus was connected to the swimmer by a low hydrodynamic resistance respiratory snorkel and valve system. The on- and off-transient phases were symmetrical in shape (mirror image) once they were adequately fitted by a single-exponential regression models, and no slow component for the oxygen uptake response was developed. Mean (± SD) peak oxygen uptake was 69.0 (± 6.3) mL·kg(-1)·min(-1), significantly correlated with time constant of the off- transient period (r = 0.76, p < 0.05) but not with any of the other oxygen off-transient kinetic parameters studied. A direct relationship between time constant of the off-transient period and mean swimming speed of the 200-m (r = 0.77, p < 0.05), and with the amplitude of the fast component of the effort period (r = 0.72, p < 0.05) were observed. The mean amplitude and time constant of the off-transient period values were significantly greater than the respective on- transient. In conclusion, although an asymmetry between the on- and off kinetic parameters was verified, both the 200-m effort and the respectively recovery period were better characterized by a single exponential regression model. Key pointsThe VO2 slow component was not observed in the recovery period of swimming extreme efforts;The on and off transient periods were better fitted by a single exponential function, and so, these effort and recovery periods of swimming extreme efforts are

  15. The Swift-BAT Hard X-Ray Transient Monitor

    NASA Technical Reports Server (NTRS)

    Krimm, H. A.; Holland, S. T.; Corbet, R. H. D.; Pearlman, A. B.; Romano, P.; Kennea, J. A.; Bloom, J. S.; Barthelmy, S. D.; Baumgartner, W. H.; Cummings, J. R.; hide

    2013-01-01

    The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as fine as 64 s. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the flux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public Web site. Between 2005 February 12 and 2013 April 30, 245 sources have been detected in the monitor, 146 of them persistent and 99 detected only in outburst. Among these sources, 17 were previously unknown and were discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and filtering for the BAT transient monitor and review its sensitivity and exposure.We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries. For the new sources that are previously unpublished, we present basic data analysis and interpretations.

  16. Predicting permanent and transient protein-protein interfaces.

    PubMed

    La, David; Kong, Misun; Hoffman, William; Choi, Youn Im; Kihara, Daisuke

    2013-05-01

    Protein-protein interactions (PPIs) are involved in diverse functions in a cell. To optimize functional roles of interactions, proteins interact with a spectrum of binding affinities. Interactions are conventionally classified into permanent and transient, where the former denotes tight binding between proteins that result in strong complexes, whereas the latter compose of relatively weak interactions that can dissociate after binding to regulate functional activity at specific time point. Knowing the type of interactions has significant implications for understanding the nature and function of PPIs. In this study, we constructed amino acid substitution models that capture mutation patterns at permanent and transient type of protein interfaces, which were found to be different with statistical significance. Using the substitution models, we developed a novel computational method that predicts permanent and transient protein binding interfaces (PBIs) in protein surfaces. Without knowledge of the interacting partner, the method uses a single query protein structure and a multiple sequence alignment of the sequence family. Using a large dataset of permanent and transient proteins, we show that our method, BindML+, performs very well in protein interface classification. A very high area under the curve (AUC) value of 0.957 was observed when predicted protein binding sites were classified. Remarkably, near prefect accuracy was achieved with an AUC of 0.991 when actual binding sites were classified. The developed method will be also useful for protein design of permanent and transient PBIs. Copyright © 2013 Wiley Periodicals, Inc.

  17. New objects do not capture attention without a sensory transient.

    PubMed

    Hollingworth, Andrew; Simons, Daniel J; Franconeri, Steven L

    2010-07-01

    Attention capture occurs when a stimulus event involuntarily recruits attention. The abrupt appearance of a new object is perhaps the most well-studied attention-capturing event, yet there is debate over the root cause of this capture. Does a new object capture attention because it involves the creation of a new object representation or because its appearance creates a characteristic luminance transient? The present study sought to resolve this question by introducing a new object into a search display, either with or without a unique luminance transient. Contrary to the results of a recent study (Davoli, Suszko, & Abrams, 2007), when the new object's transient was masked by a brief interstimulus interval introduced between the placeholder and search arrays, a new object did not capture attention. Moreover, when a new object's transient was masked, participants could not locate a new object efficiently even when that was their explicit goal. Together, these data suggest that luminance transient signals are necessary for attention capture by new objects.

  18. Automation of large scale transient protein expression in mammalian cells

    PubMed Central

    Zhao, Yuguang; Bishop, Benjamin; Clay, Jordan E.; Lu, Weixian; Jones, Margaret; Daenke, Susan; Siebold, Christian; Stuart, David I.; Yvonne Jones, E.; Radu Aricescu, A.

    2011-01-01

    Traditional mammalian expression systems rely on the time-consuming generation of stable cell lines; this is difficult to accommodate within a modern structural biology pipeline. Transient transfections are a fast, cost-effective solution, but require skilled cell culture scientists, making man-power a limiting factor in a setting where numerous samples are processed in parallel. Here we report a strategy employing a customised CompacT SelecT cell culture robot allowing the large-scale expression of multiple protein constructs in a transient format. Successful protocols have been designed for automated transient transfection of human embryonic kidney (HEK) 293T and 293S GnTI− cells in various flask formats. Protein yields obtained by this method were similar to those produced manually, with the added benefit of reproducibility, regardless of user. Automation of cell maintenance and transient transfection allows the expression of high quality recombinant protein in a completely sterile environment with limited support from a cell culture scientist. The reduction in human input has the added benefit of enabling continuous cell maintenance and protein production, features of particular importance to structural biology laboratories, which typically use large quantities of pure recombinant proteins, and often require rapid characterisation of a series of modified constructs. This automated method for large scale transient transfection is now offered as a Europe-wide service via the P-cube initiative. PMID:21571074

  19. Transient times in linear metabolic pathways under constant affinity constraints.

    PubMed

    Lloréns, M; Nuño, J C; Montero, F

    1997-10-15

    In the early seventies, Easterby began the analytical study of transition times for linear reaction schemes [Easterby (1973) Biochim. Biophys. Acta 293, 552-558]. In this pioneer work and in subsequent papers, a state function (the transient time) was used to measure the period before the stationary state, for systems constrained to work under both constant and variable input flux, was reached. Despite the undoubted usefulness of this quantity to describe the time-dependent features of these kinds of systems, its application to the study of chemical reactions under other constraints is questionable. In the present work, a generalization of these magnitudes to linear metabolic pathways functioning under a constant-affinity constraint is carried out. It is proved that classical definitions of transient times do not reflect the actual properties of the transition to the steady state in systems evolving under this restriction. Alternatively, a more adequate framework for interpretation of the transient times for systems with both constant and variable input flux is suggested. Within this context, new definitions that reflect more accurately the transient characteristics of constant affinity systems are stated. Finally, the meaning of these transient times is discussed.

  20. Analytic Thermoelectric Couple Modeling: Variable Material Properties and Transient Operation

    NASA Technical Reports Server (NTRS)

    Mackey, Jonathan A.; Sehirlioglu, Alp; Dynys, Fred

    2015-01-01

    To gain a deeper understanding of the operation of a thermoelectric couple a set of analytic solutions have been derived for a variable material property couple and a transient couple. Using an analytic approach, as opposed to commonly used numerical techniques, results in a set of useful design guidelines. These guidelines can serve as useful starting conditions for further numerical studies, or can serve as design rules for lab built couples. The analytic modeling considers two cases and accounts for 1) material properties which vary with temperature and 2) transient operation of a couple. The variable material property case was handled by means of an asymptotic expansion, which allows for insight into the influence of temperature dependence on different material properties. The variable property work demonstrated the important fact that materials with identical average Figure of Merits can lead to different conversion efficiencies due to temperature dependence of the properties. The transient couple was investigated through a Greens function approach; several transient boundary conditions were investigated. The transient work introduces several new design considerations which are not captured by the classic steady state analysis. The work helps to assist in designing couples for optimal performance, and also helps assist in material selection.

  1. Large liquid rocket engine transient performance simulation system

    NASA Technical Reports Server (NTRS)

    Mason, J. R.; Southwick, R. D.

    1991-01-01

    A simulation system, ROCETS, was designed and developed to allow cost-effective computer predictions of liquid rocket engine transient performance. The system allows a user to generate a simulation of any rocket engine configuration using component modules stored in a library through high-level input commands. The system library currently contains 24 component modules, 57 sub-modules and maps, and 33 system routines and utilities. FORTRAN models from other sources can be operated in the system upon inclusion of interface information on comment cards. Operation of the simulation is simplified for the user by run, execution, and output processors. The simulation system makes available steady-state trim balance, transient operation, and linear partial generation. The system utilizes a modern equation solver for efficient operation of the simulations. Transient integration methods include integral and differential forms for the trapezoidal, first order Gear, and second order Gear corrector equations. A detailed technology test bed engine (TTBE) model was generated to be used as the acceptance test of the simulation system. The general level of model detail was that reflected in the Space Shuttle Main Engine DTM. The model successfully obtained steady-state balance in main stage operation and simulated throttle transients, including engine starts and shutdown. A NASA FORTRAN control model was obtained, ROCETS interface installed in comment cards, and operated with the TTBE model in closed-loop transient mode.

  2. Transient response of sap flow to wind speed.

    PubMed

    Chu, Chia R; Hsieh, Cheng-I; Wu, Shen-Yuang; Phillips, Nathan G

    2009-01-01

    Transient responses of sap flow to step changes in wind speed were experimentally investigated in a wind tunnel. A Granier-type sap flow sensor was calibrated and tested in a cylindrical tube for analysis of its transient time response. Then the sensor was used to measure the transient response of a well-watered Pachira macrocarpa plant to wind speed variations. The transient response of sap flow was described using the resistance-capacitance model. The steady sap flow rate increased as the wind speed increased at low wind speeds. Once the wind speed exceeded 8.0 m s(-1), the steady sap flow rate did not increase further. The transpiration rate, measured gravimetrically, showed a similar trend. The response of nocturnal sap flow to wind speed variation was also measured and compared with the results in the daytime. Under the same wind speed, the steady sap flow rate was smaller than that in the daytime, indicating differences between diurnal and nocturnal hydraulic function, and incomplete stomatal closure at night. In addition, it was found that the temporal response of the Granier sensor is fast enough to resolve the transient behaviour of water flux in plant tissue.

  3. CosmoQuest Transient Tracker: Opensource Photometry & Astrometry software

    NASA Astrophysics Data System (ADS)

    Myers, Joseph L.; Lehan, Cory; Gay, Pamela; Richardson, Matthew; CosmoQuest Team

    2018-01-01

    CosmoQuest is moving from online citizen science, to observational astronomy with the creation of Transient Trackers. This open source software is designed to identify asteroids and other transient/variable objects in image sets. Transient Tracker’s features in final form will include: astrometric and photometric solutions, identification of moving/transient objects, identification of variable objects, and lightcurve analysis. In this poster we present our initial, v0.1 release and seek community input.This software builds on the existing NIH funded ImageJ libraries. Creation of this suite of opensource image manipulation routines is lead by Wayne Rasband and is released primarily under the MIT license. In this release, we are building on these libraries to add source identification for point / point-like sources, and to do astrometry. Our materials released under the Apache 2.0 license on github (http://github.com/CosmoQuestTeam) and documentation can be found at http://cosmoquest.org/TransientTracker.

  4. Transient creep and semibrittle behavior of crystalline rocks

    Carter, N.L.; Kirby, S.H.

    1978-01-01

    We review transient creep and semibrittle behavior of crystalline solids. The results are expected to be pertinent to crystalline rocks undergoing deformation in the depth range 5 to 20 km, corresponding to depths of focus of many major earthquakes. Transient creep data for crystalline rocks at elevated temperatures are analyzed but are poorly understood because of lack of information on the deformation processes which, at low to moderate pressure, are likely to be semibrittle in nature. Activation energies for transient creep at high effective confining pressure are much higher than those found for atmospheric pressure tests in which thermally-activated microfracturing probably dominates the creep rate. Empirical transient creep equations are extrapolated at 200?? to 600??C, stresses from 0.1 to 1.0 kbar, to times ranging from 3.17??102 to 3.17??108 years. At the higher temperatures, appreciable transient creep strains may take place but the physical significance of the results is in question because the flow mechanisms have not been determined. The purpose of this paper is to stimulate careful research on this important topic. ?? 1978 Birkha??user Verlag.

  5. THE SWIFT/BAT HARD X-RAY TRANSIENT MONITOR

    SciT

    Krimm, H. A.; Holland, S. T.; Corbet, R. H. D.

    2013-11-01

    The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as fine as 64 s. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the flux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. Themore » primary interface for the BAT transient monitor is a public Web site. Between 2005 February 12 and 2013 April 30, 245 sources have been detected in the monitor, 146 of them persistent and 99 detected only in outburst. Among these sources, 17 were previously unknown and were discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and filtering for the BAT transient monitor and review its sensitivity and exposure. We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries. For the new sources that are previously unpublished, we present basic data analysis and interpretations.« less

  6. The Swift/BAT Hard X-ray Transient Monitor

    NASA Technical Reports Server (NTRS)

    Krimm, H. A.; Holland, S. T.; Corbet, R.H.D.; Pearlman, A. B.; Romano, P.; Kennea, J. A.; Bloom, J. S.; Barthelmy, S. D.; Baumgartner, W. H.; Cummings, J. R.; hide

    2013-01-01

    The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as ne as 64 seconds. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the ux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public web page. Since 2005 February, 242 sources have been detected in the monitor, 149 of them persistent and 93 detected only in outburst. Among these sources, 16 were previously unknown and discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and ltering for the BAT transient monitor and review its sensitivity and exposure. We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries and present basic data analysis and interpretations for those sources with previously unpublished results.

  7. Advanced simulation study on bunch gap transient effect

    NASA Astrophysics Data System (ADS)

    Kobayashi, Tetsuya; Akai, Kazunori

    2016-06-01

    Bunch phase shift along the train due to a bunch gap transient is a concern in high-current colliders. In KEKB operation, the measured phase shift along the train agreed well with a simulation and a simple analytical form in most part of the train. However, a rapid phase change was observed at the leading part of the train, which was not predicted by the simulation or by the analytical form. In order to understand the cause of this observation, we have developed an advanced simulation, which treats the transient loading in each of the cavities of the three-cavity system of the accelerator resonantly coupled with energy storage (ARES) instead of the equivalent single cavities used in the previous simulation, operating in the accelerating mode. In this paper, we show that the new simulation reproduces the observation, and clarify that the rapid phase change at the leading part of the train is caused by a transient loading in the three-cavity system of ARES. KEKB is being upgraded to SuperKEKB, which is aiming at 40 times higher luminosity than KEKB. The gap transient in SuperKEKB is investigated using the new simulation, and the result shows that the rapid phase change at the leading part of the train is much larger due to higher beam currents. We will also present measures to mitigate possible luminosity reduction or beam performance deterioration due to the rapid phase change caused by the gap transient.

  8. Transient thermal stress problem for a circumferentially cracked hollow cylinder

    NASA Technical Reports Server (NTRS)

    Nied, H. F.; Erdogan, F.

    1983-01-01

    The paper is concerned with the transient thermal stress problem for a long hollow circular cylinder containing an internal axisymmetric circumferential edge crack that is suddenly cooled from inside. It is assumed that the transient thermal stress problem is quasi-static, i.e., the inertial effects are negligible. Also, all thermoelastic coupling effects and the possible temperature dependence of the thermoelastic constants are neglected. The problem is considered in two parts. The first part is the evaluation of transient thermal stresses in an uncracked cylinder; the second part is the isothermal perturbation problem for the cracked cylinder in which the crack surface tractions, equal and opposite to the thermal stresses obtained from the first problem, are the only external loads. The superposition of the two solutions gives results for the cracked cylinder.

  9. PRESSURE PULSES AT VOYAGER 2 : DRIVERS OF INTERSTELLAR TRANSIENTS?

    SciT

    Richardson, J. D.; Wang, C.; Liu, Y. D.

    Voyager 1 ( V1 ) crossed the heliopause into the local interstellar medium (LISM) in 2012. The LISM is a dynamic region periodically disturbed by solar transients with outward-propagating shocks, cosmic-ray intensity changes and anisotropies, and plasma wave oscillations. Voyager 2 ( V2 ) trails V1 and thus may observe the solar transients that are later observed at V1. V2 crossed the termination shock in 2007 and is now in the heliosheath. Starting in 2012, when solar maximum conditions reached V2 , five possible merged interaction regions (MIRs) have been observed by V2 in the heliosheath. The timing is consistentmore » with these MIRs driving the transients observed by V1 in the LISM. The largest heliosheath MIR was observed by V2 in late 2015 and should reach V1 in 2018.« less

  10. On a method computing transient wave propagation in ionospheric regions

    NASA Technical Reports Server (NTRS)

    Gray, K. G.; Bowhill, S. A.

    1978-01-01

    A consequence of an exoatmospheric nuclear burst is an electromagnetic pulse (EMP) radiated from it. In a region far enough away from the burst, where nonlinear effects can be ignored, the EMP can be represented by a large-amplitude narrow-time-width plane-wave pulse. If the ionosphere intervenes the origin and destination of the EMP, frequency dispersion can cause significant changes in the original pulse upon reception. A method of computing these dispersive effects of transient wave propagation is summarized. The method described is different from the standard transform techniques and provides physical insight into the transient wave process. The method, although exact, can be used in approximating the early-time transient response of an ionospheric region by a simple integration with only explicit knowledge of the electron density, electron collision frequency, and electron gyrofrequency required. As an illustration of the method, it is applied to a simple example and contrasted with the corresponding transform solution.

  11. Transient finite element modeling of functional electrical stimulation.

    PubMed

    Filipovic, Nenad D; Peulic, Aleksandar S; Zdravkovic, Nebojsa D; Grbovic-Markovic, Vesna M; Jurisic-Skevin, Aleksandra J

    2011-03-01

    Transcutaneous functional electrical stimulation is commonly used for strengthening muscle. However, transient effects during stimulation are not yet well explored. The effect of an amplitude change of the stimulation can be described by static model, but there is no differency for different pulse duration. The aim of this study is to present the finite element (FE) model of a transient electrical stimulation on the forearm. Discrete FE equations were derived by using a standard Galerkin procedure. Different tissue conductive and dielectric properties are fitted using least square method and trial and error analysis from experimental measurement. This study showed that FE modeling of electrical stimulation can give the spatial-temporal distribution of applied current in the forearm. Three different cases were modeled with the same geometry but with different input of the current pulse, in order to fit the tissue properties by using transient FE analysis. All three cases were compared with experimental measurements of intramuscular voltage on one volunteer.

  12. Building pit dewatering: application of transient analytic elements.

    PubMed

    Zaadnoordijk, Willem J

    2006-01-01

    Analytic elements are well suited for the design of building pit dewatering. Wells and drains can be modeled accurately by analytic elements, both nearby to determine the pumping level and at some distance to verify the targeted drawdown at the building site and to estimate the consequences in the vicinity. The ability to shift locations of wells or drains easily makes the design process very flexible. The temporary pumping has transient effects, for which transient analytic elements may be used. This is illustrated using the free, open-source, object-oriented analytic element simulator Tim(SL) for the design of a building pit dewatering near a canal. Steady calculations are complemented with transient calculations. Finally, the bandwidths of the results are estimated using linear variance analysis.

  13. Illicit dopamine transients: reconciling actions of abused drugs.

    PubMed

    Covey, Dan P; Roitman, Mitchell F; Garris, Paul A

    2014-04-01

    Phasic increases in brain dopamine are required for cue-directed reward seeking. Although compelling within the framework of appetitive behavior, the view that illicit drugs hijack reward circuits by hyperactivating these dopamine transients is inconsistent with established psychostimulant pharmacology. However, recent work reclassifying amphetamine (AMPH), cocaine, and other addictive dopamine-transporter inhibitors (DAT-Is) supports transient hyperactivation as a unifying hypothesis of abused drugs. We argue here that reclassification also identifies generating burst firing by dopamine neurons as a keystone action. Unlike natural rewards, which are processed by sensory systems, drugs act directly on the brain. Consequently, to mimic natural rewards and exploit reward circuits, dopamine transients must be elicited de novo. Of available drug targets, only burst firing achieves this essential outcome. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Continuation of surge life of transient voltage suppressor

    NASA Technical Reports Server (NTRS)

    Clark, O. M.

    1977-01-01

    Efforts expended in testing, analyzing and the development of a meaningful definition of the mean number of peak pulses before failure (mp2bf) levels of a family of transient voltage suppressor devices were documented. Tests were done to determine the ability of the transient suppressor to effectively and reliably protect against severe short term, millisecond range, and transient voltages of the types resulting from inductive load switching and induced lightning. Existing pulse testing instrumentation was utilized, interfaced to an automatic sequencing test rack accommodating up to 50 devices. Tests were performed in step stress increments of 25% beginning at 25% and extending thru 100% rated I(pp) for each voltage category. The four voltage types test were the 6.8V, 33V, 91V, and 190V. Engineering efforts addressed the problem of improving the reliability of the 190V types.

  15. Sensitivity Equation Derivation for Transient Heat Transfer Problems

    NASA Technical Reports Server (NTRS)

    Hou, Gene; Chien, Ta-Cheng; Sheen, Jeenson

    2004-01-01

    The focus of the paper is on the derivation of sensitivity equations for transient heat transfer problems modeled by different discretization processes. Two examples will be used in this study to facilitate the discussion. The first example is a coupled, transient heat transfer problem that simulates the press molding process in fabrication of composite laminates. These state equations are discretized into standard h-version finite elements and solved by a multiple step, predictor-corrector scheme. The sensitivity analysis results based upon the direct and adjoint variable approaches will be presented. The second example is a nonlinear transient heat transfer problem solved by a p-version time-discontinuous Galerkin's Method. The resulting matrix equation of the state equation is simply in the form of Ax = b, representing a single step, time marching scheme. A direct differentiation approach will be used to compute the thermal sensitivities of a sample 2D problem.

  16. ILLICIT DOPAMINE TRANSIENTS: RECONCILING ACTIONS OF ABUSED DRUGS

    PubMed Central

    Covey, Dan P.; Roitman, Mitchell F.; Garris, Paul A.

    2014-01-01

    Phasic increases in brain dopamine are required for cue-directed reward seeking. While compelling within the framework of appetitive behavior, the view that illicit drugs hijack reward circuits by hyper-activating these dopamine transients is inconsistent with established psychostimulant pharmacology. However, recent work reclassifying amphetamine (AMPH), cocaine, and other addictive dopamine-transporter inhibitors (DAT-Is) supports transient hyper-activation as a unifying hypothesis of abused drugs. We argue here that reclassification also identifies generating burst firing by dopamine neurons as a keystone action. Unlike natural rewards, which are processed by sensory systems, drugs act directly on the brain. Consequently, to mimic natural reward and exploit reward circuits, dopamine transients must be elicited de novo. Of available drug targets, only burst firing achieves this essential outcome. PMID:24656971

  17. Transient Micromotors That Disappear When No Longer Needed.

    PubMed

    Chen, Chuanrui; Karshalev, Emil; Li, Jinxing; Soto, Fernando; Castillo, Roxanne; Campos, Isaac; Mou, Fangzhi; Guan, Jianguo; Wang, Joseph

    2016-11-22

    Transient self-destroyed micromotors that autonomously disappear in biological media at controlled rates upon completing their task, without leaving a toxic residue, are presented. The propulsion and degradation characteristics of the self-destroyed Mg/ZnO, Mg/Si, and Zn/Fe Janus micromotors and single-component Zn micromotors are described. The degradation of the Janus micromotors relies on the different corrosion rates of their core-shell components. Inductively coupled plasma optical emission spectrometry measurements are used to probe the time-dependent degradation of the different constituents of the micromotors. The toxicity of the transient micromotors is discussed toward their potential use in biomedical applications. This concept of transient micromotors offers considerable potential for diverse practical applications in the near future.

  18. Ultrafast transient grating radiation to optical image converter

    DOEpatents

    Stewart, Richard E; Vernon, Stephen P; Steel, Paul T; Lowry, Mark E

    2014-11-04

    A high sensitivity transient grating ultrafast radiation to optical image converter is based on a fixed transmission grating adjacent to a semiconductor substrate. X-rays or optical radiation passing through the fixed transmission grating is thereby modulated and produces a small periodic variation of refractive index or transient grating in the semiconductor through carrier induced refractive index shifts. An optical or infrared probe beam tuned just below the semiconductor band gap is reflected off a high reflectivity mirror on the semiconductor so that it double passes therethrough and interacts with the radiation induced phase grating therein. A small portion of the optical beam is diffracted out of the probe beam by the radiation induced transient grating to become the converted signal that is imaged onto a detector.

  19. Transient Plasma Photonic Crystals for High-Power Lasers.

    PubMed

    Lehmann, G; Spatschek, K H

    2016-06-03

    A new type of transient photonic crystals for high-power lasers is presented. The crystal is produced by counterpropagating laser beams in plasma. Trapped electrons and electrically forced ions generate a strong density grating. The lifetime of the transient photonic crystal is determined by the ballistic motion of ions. The robustness of the photonic crystal allows one to manipulate high-intensity laser pulses. The scheme of the crystal is analyzed here by 1D Vlasov simulations. Reflection or transmission of high-power laser pulses are predicted by particle-in-cell simulations. It is shown that a transient plasma photonic crystal may act as a tunable mirror for intense laser pulses. Generalizations to 2D and 3D configurations are possible.

  20. TRANSIENT BEAM LOADING EFFECTS IN RF SYSTEMS IN JLEIC

    SciT

    Wang, Haipeng; Guo, Jiquan; Rimmer, Robert A.

    2016-05-01

    The pulsed electron bunch trains generated from the Continuous Electron Beam Accelerator Facility (CEBAF) linac to inject into the proposed Jefferson Lab Electron Ion Collider (JLEIC) e-ring will produce transient beam loading effects in the Superconducting Radio Frequency (SRF) systems that, if not mitigated, could cause unacceptably large beam energy deviation in the injection capture, or exceed the energy acceptance of CEBAF’s recirculating arcs. In the electron storage ring, the beam abort or ion clearing gaps or uneven bucket filling can cause large beam phase transients in the (S)RF cavity control systems and even beam loss due to Robinson instability.more » We have first analysed the beam stability criteria in steady state and estimated the transient effect in Feedforward and Feedback RF controls. Initial analytical models for these effects are shown for the design of the JLEIC e-ring from 3GeV to 12GeV.« less

  1. Transient Stability Output Margin Estimation Based on Energy Function Method

    NASA Astrophysics Data System (ADS)

    Miwa, Natsuki; Tanaka, Kazuyuki

    In this paper, a new method of estimating critical generation margin (CGM) in power systems is proposed from the viewpoint of transient stability diagnostic. The proposed method has the capability to directly compute the stability limit output for a given contingency based on transient energy function method (TEF). Since CGM can be directly obtained by the limit output using estimated P-θ curves and is easy to understand, it is more useful rather than conventional critical clearing time (CCT) of energy function method. The proposed method can also estimate CGM as its negative value that means unstable in present load profile, then negative CGM can be directly utilized as generator output restriction. The proposed method is verified its accuracy and fast solution ability by applying to simple 3-machine model and IEEJ EAST10-machine standard model. Furthermore the useful application to severity ranking of transient stability for a lot of contingency cases is discussed by using CGM.

  2. PESSTO: The Public ESO Spectroscopic Survey of Transient Objects

    NASA Astrophysics Data System (ADS)

    Smartt, S. J.; Valenti, S.; Fraser, M.; Inserra, C.; Young, D. R.; Sullivan, M.; Benetti, S.; Gal-Yam, A.; Knapic, C.; Molinaro, M.; Pastorello, A.; Smareglia, R.; Smith, K. W.; Taubenberger, S.; Yaron, O.

    2013-12-01

    PESSTO, which began in April 2012 as one of two ESO public spectroscopic surveys, uses the EFOSC2 and SOFI instruments on the New Technology Telescope during ten nights a month for nine months of the year. Transients for PESSTO follow-up are provided by dedicated large-field 1-2-metre telescope imaging surveys. In its first year PESSTO classified 263 optical transients, publicly released the reduced spectra within 12 hours of the end of the night and identified 33 supernovae (SNe) for dedicated follow-up campaigns. Nine papers have been published or submitted on the topics of supernova progenitors, the origins of type ia SNe, the uncertain nature of faint optical transients and superluminous supernovae, and a definitive public dataset on a most intriguing supernova, the infamous SN2009ip.

  3. UNSUPERVISED TRANSIENT LIGHT CURVE ANALYSIS VIA HIERARCHICAL BAYESIAN INFERENCE

    SciT

    Sanders, N. E.; Soderberg, A. M.; Betancourt, M., E-mail: nsanders@cfa.harvard.edu

    2015-02-10

    Historically, light curve studies of supernovae (SNe) and other transient classes have focused on individual objects with copious and high signal-to-noise observations. In the nascent era of wide field transient searches, objects with detailed observations are decreasing as a fraction of the overall known SN population, and this strategy sacrifices the majority of the information contained in the data about the underlying population of transients. A population level modeling approach, simultaneously fitting all available observations of objects in a transient sub-class of interest, fully mines the data to infer the properties of the population and avoids certain systematic biases. Wemore » present a novel hierarchical Bayesian statistical model for population level modeling of transient light curves, and discuss its implementation using an efficient Hamiltonian Monte Carlo technique. As a test case, we apply this model to the Type IIP SN sample from the Pan-STARRS1 Medium Deep Survey, consisting of 18,837 photometric observations of 76 SNe, corresponding to a joint posterior distribution with 9176 parameters under our model. Our hierarchical model fits provide improved constraints on light curve parameters relevant to the physical properties of their progenitor stars relative to modeling individual light curves alone. Moreover, we directly evaluate the probability for occurrence rates of unseen light curve characteristics from the model hyperparameters, addressing observational biases in survey methodology. We view this modeling framework as an unsupervised machine learning technique with the ability to maximize scientific returns from data to be collected by future wide field transient searches like LSST.« less

  4. Sustained and transient attention in the continuous performance task.

    PubMed

    Smid, H G O M; de Witte, M R; Homminga, I; van den Bosch, R J

    2006-08-01

    One of the most frequently applied methods to study abnormal cognition is the Continuous Performance Task (CPT). It is unclear, however, which cognitive functions are engaged in normal CPT performance. The aims of the present study were to identify the neurocognitive functions engaged in the main variants of the CPT and to determine to what extent these variants differentially engage these functions. We hypothesized that the main CPT versions (CPT-X, CPT-AX, CPT-Identical Pairs) can be distinguished by whether they demand sustained or transient attention and sustained or transient response preparation. Transient attention to objects like letters or digits, that is, the need to switch attention to different objects from trial to trial, impairs target detection accuracy relative to sustained attention to a single object. Transient response preparation, that is, the possibility to switch response preparation on and off from trial to trial, improves response speed relative to having to sustain response preparation across all trials. Comparison of task performance and Event-Related brain Potentials (ERPs) of healthy participants obtained in the main CPT variants confirmed these hypotheses. Behavioral and ERP measures indicated worse target detection in the CPT-AX than in the CPT-X, consistent with a higher demand on transient attention in that task. In contrast, behavioral and ERP measures indicated higher response speed in the CPT-AX than in the CPT-X, associated with more response preparation in advance of the targets. This supports the idea of increased transient response preparation in the CPT-AX. We conclude that CPTs differ along at least two task variables that each influences a different cognitive function.

  5. The Pan-STARRS Survey for Transients (PSST)

    NASA Astrophysics Data System (ADS)

    Huber, Mark; Carter Chambers, Kenneth; Flewelling, Heather; Smartt, Stephen J.; Smith, Ken; Wright, Darryl

    2015-08-01

    The Pan-STARRS1 (PS1) Science Consortium finished the 3Pi survey of the whole sky north of -30 degrees between 2010-2014 in grizy (PS1 specific filters) and the PS1 telescope has been running a wide-field survey for near earth objects, funded by NASA through the NEO Observation Program. This survey takes data in a w-band (wide-band filter spanning g,r,i) in dark time, and combinations of r, i, z and y during bright time. We are now processing these data through the Pan-STARRS IPP difference imaging pipeline and recovering stationary transients. Effectively the 3Pi survey for transients that started during the PS1 Science Consortium is being continued under the new NEO optimized operations mode. The observing procedure in this case is to take a quad of exposures, typically 30-45 seconds separated by 10-20 minutes each, typically revealing high confidence transients (greater than 5-sigma) to depths of i~ 20.7, y~18.3 (AB mags). This cadence may be repeated on subsequent nights in a return pointing.Continuing the public release of the first 880 transients from the PS1 3Pi survey during the search period September 2013 - January 2014, beginning February 2015, the transient events using the data from the the Pan-STARRS NEO Science Consortium are now regularly added. These are mostly supernova candidates, but the list also contains some variable stars, AGN, and nuclear transients. The light curves are too sparsely sampled to be of standalone use, but they may be of use to the community in combining with existing data (e.g. Fraser et al. 2013, ApJ, 779, L8), constraining explosion and rise times (e.g. Nicholl et al. 2013, Nature, 502, 346) as well as many being new discoveries.For additional details visit http://star.pst.qub.ac.uk/ps1threepi/

  6. Rotamer-Specific Photoisomerization of Difluorostilbenes from Transient Absorption and Transient Raman Spectroscopy.

    PubMed

    Quick, M; Dobryakov, A L; Ioffe, I N; Berndt, F; Mahrwald, R; Ernsting, N P; Kovalenko, S A

    2018-01-25

    Photoisomerization of 2,2'-, 3,3'-, and 4,4'-difluorostilbene (F2, F3, F4, respectively) in n-hexane, perfluoro-n-hexane, and acetonitrile is studied with broadband transient absorption (TA) and femtosecond stimulated Raman (FSR) spectroscopy and by DFT/TDDFT calculations. F2 and F3 possess three rotamers (rotational isomers) each, while F4 has one single conformation only. These differences are reflected in TA and FSR spectra. Thus F4 reveals a monoexponential decay of TA with τ 1 = 172 ps in n-hexane, as expected for a single species. For F2 and F3, the decays are biexponential in all solvents, corresponding to two distinctly discerned rotamers or rotamer fractions. Specifically, for F2 in n-hexane, τ 1 = 357 ps (83%) and τ 2 = 62 ps (17%), and for F3 in the same solvent, τ 1 = 222 ps (57%), and τ 2 = 81 ps (43%). The weights in brackets agree with theoretically estimated ground-state abundances of the rotamers. Furthermore, a global fit of the TA and FSR data allows us to extract the spectra of the pure rotamers. The Raman spectra of S 0 and S 1 are in qualitative agreement with calculations.

  7. Transient dynamics of a flexible rotor with squeeze film dampers

    NASA Technical Reports Server (NTRS)

    Buono, D. F.; Schlitzer, L. D.; Hall, R. G., III; Hibner, D. H.

    1978-01-01

    A series of simulated blade loss tests are reported on a test rotor designed to operate above its second bending critical speed. A series of analyses were performed which predicted the transient behavior of the test rig for each of the blade loss tests. The scope of the program included the investigation of transient rotor dynamics of a flexible rotor system, similar to modern flexible jet engine rotors, both with and without squeeze film dampers. The results substantiate the effectiveness of squeeze film dampers and document the ability of available analytical methods to predict their effectiveness and behavior.

  8. Rendering Protein-Based Particles Transiently Insoluble for Therapeutic Applications

    PubMed Central

    Xu, Jing; Wang, Jin; Luft, J. Christopher; Tian, Shaomin; Owens, Gary; Pandya, Ashish A.; Berglund, Peter; Pohlhaus, Patrick; Maynor, Benjamin W.; Napier, Mary E.; DeSimone, Joseph M.

    2012-01-01

    Herein we report the fabrication of protein (bovine serum albumin, BSA) particles which were rendered transiently insoluble using a novel, reductively labile disulfide-based cross-linker. After being cross-linked, the protein particles retain their integrity in aqueous solution and dissolve preferentially under a reducing environment. Our data demonstrates that cleavage of the cross-linker leaves no chemical residue on the reactive amino group. Delivery of a self-replicating RNA was achieved via the transiently insoluble PRINT protein particles. These protein particles can provide new opportunities for drug and gene delivery. PMID:22568387

  9. Transient Reliability of Ceramic Structures For Heat Engine Applications

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Jadaan, Osama M.

    2002-01-01

    The objectives of this report was to develop a methodology to predict the time-dependent reliability (probability of failure) of brittle material components subjected to transient thermomechanical loading, taking into account the change in material response with time. This methodology for computing the transient reliability in ceramic components subjected to fluctuation thermomechanical loading was developed, assuming SCG (Slow Crack Growth) as the delayed mode of failure. It takes into account the effect of varying Weibull modulus and materials with time. It was also coded into a beta version of NASA's CARES/Life code, and an example demonstrating its viability was presented.

  10. The Transient High Energy Sky and Early Universe Surveyor

    NASA Astrophysics Data System (ADS)

    O'Brien, P. T.

    2016-04-01

    The Transient High Energy Sky and Early Universe Surveyor is a mission which will be proposed for the ESA M5 call. THESEUS will address multiple components in the Early Universe ESA Cosmic Vision theme:4.1 Early Universe,4.2 The Universe taking shape, and4.3 The evolving violent Universe.THESEUS aims at vastly increasing the discovery space of the high energy transient phenomena over the entire cosmic history. This is achieved via a unique payload providing an unprecedented combination of: (i) wide and deep sky monitoring in a broad energy band(0.3 keV-20 MeV; (ii) focusing capabilities in the soft X-ray band granting large grasp and high angular resolution; and (iii) on board near-IR capabilities for immediate transient identification and first redshift estimate.The THESEUS payload consists of: (i) the Soft X--ray Imager (SXI), a set of Lobster Eye (0.3--6 keV) telescopes with CCD detectors covering a total FOV of 1 sr; (ii) the X--Gamma-rays spectrometer (XGS), a non-imaging spectrometer (XGS) based on SDD+CsI, covering the same FOV than the Lobster telescope extending the THESEUS energy band up to 20 MeV; and (iii) a 70cm class InfraRed Telescope (IRT) observing up to 2 microns with imaging and moderate spectral capabilities.The main scientific goals of THESEUS are to:(a) Explore the Early Universe (cosmic dawn and reionization era) by unveiling the Gamma--Ray Burst (GRBs) population in the first billion years}, determining when did the first stars form, and investigating the re-ionization epoch, the interstellar medium (ISM) and the intergalactic medium (IGM) at high redshifts.(b) Perform an unprecedented deep survey of the soft X-ray transient Universe in order to fill the present gap in the discovery space of new classes of transient; provide a fundamental step forward in the comprehension of the physics of various classes of Galactic and extra--Galactic transients, and provide real time trigger and accurate locations of transients for follow-up with next

  11. Alternatives Analysis for the Resumption of Transient Testing Program

    SciT

    Lee Nelson

    2013-11-01

    An alternatives analysis was performed for resumption of transient testing. The analysis considered eleven alternatives – including both US international facilities. A screening process was used to identify two viable alternatives from the original eleven. In addition, the alternatives analysis includes a no action alternative as required by the National Environmental Policy Act (NEPA). The alternatives considered in this analysis included: 1. Restart the Transient Reactor Test Facility (TREAT) 2. Modify the Annular Core Research Reactor (ACRR) which includes construction of a new hot cell and installation of a new hodoscope. 3. No Action

  12. Simulation of transient effects in the heavy ion fusion injectors

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Jiuan; Hewett, D. W.

    1993-05-01

    We have used the 2-D PIC code, GYMNOS, to study the transient behaviors in the Heavy Ion Fusion (HIF) injectors. GYMNOS simulations accurately provide the steady state Child-Langmuir current and the beam transient behavior within a planar diode. The simulations of the LBL HIF ESAC injector experiments agree well with the experimental data and EGUN steady state results. Simulations of the nominal HIF injectors have revealed the need to design the accelerating electrodes carefully to control the ion beam current, particularly the ion loss at the end of the bunch as the extraction voltage is reduced.

  13. Experimental Validation of a Closed Brayton Cycle System Transient Simulation

    NASA Technical Reports Server (NTRS)

    Johnson, Paul K.; Hervol, David S.

    2006-01-01

    The Brayton Power Conversion Unit (BPCU) located at NASA Glenn Research Center (GRC) in Cleveland, Ohio was used to validate the results of a computational code known as Closed Cycle System Simulation (CCSS). Conversion system thermal transient behavior was the focus of this validation. The BPCU was operated at various steady state points and then subjected to transient changes involving shaft rotational speed and thermal energy input. These conditions were then duplicated in CCSS. Validation of the CCSS BPCU model provides confidence in developing future Brayton power system performance predictions, and helps to guide high power Brayton technology development.

  14. Acute transient phlebitis during eptifibatide intravenous injection: case report.

    PubMed

    Hay, Emile; Blaer, Yossef; Shlyakhover, Vladimir; Katz, Amos; Jafari, Jamal

    2010-01-01

    We present a 56-year-old man who developed acute transient phlebitis of the right cephalic vein during an intravenous injection of eptifibatide (Integrilin, Schering Plough, Kenilworth, NJ). The eptifibatide injections were discontinued, and signs of phlebitis disappeared within minutes. The patient's course was uneventful, and he was discharged home after 8 days. As far as we know, this is the first report of acute transient phlebitis during intravenous eptifibatide injections in the English-language medical literature. Copyright 2010 Elsevier Inc. All rights reserved.

  15. A novel plant protection strategy for transient reactors

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Samit K.; Lipinski, Walter C.; Hanan, Nelson A.

    A novel plant protection system designed for use in the TREAT Upgrade (TU) reactor is described. The TU reactor is designed for controlled transient operation in the testing of reactor fuel behavior under simulated reactor accident conditions. Safe operation of the reactor is of paramount importance and the Plant Protection System (PPS) had to be designed to exacting requirements. Researchers believe that the strategy developed for the TU has potential application to the multimegawatt space reactors and represents the state of the art in terrestrial transient reactor protection systems.

  16. A novel plant protection strategy for transient reactors

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Samit K.; Lipinski, Walter C.; Hanan, Nelson A.

    The present plant protection system (PPS) has been defined for use in the TREAT-upgrade (TU) reactor for controlled transient operation of reactor-fuel behavior testing under simulated reactor-accident conditions. A PPS with energy-dependent trip set points lowered worst-case clad temperatures by as much as 180 K, relative to the use of conventional fixed-level trip set points. The multilayered multilevel protection strategy represents the state-of-the-art in terrestrial transient reactor protection systems, and should be applicable to multi-MW space reactors.

  17. Stepwise and Pulse Transient Methods of Thermophysical Parameters Measurement

    NASA Astrophysics Data System (ADS)

    Malinarič, Svetozár; Dieška, Peter

    2016-12-01

    Stepwise transient and pulse transient methods are experimental techniques for measuring the thermal diffusivity and conductivity of solid materials. Theoretical models and experimental apparatus are presented, and the influence of the heat source capacity and the heat transfer coefficient is investigated using the experiment simulation. The specimens from low-density polyethylene (LDPE) and polymethylmethacrylate (PMMA) were measured by both methods. Coefficients of variation were better than 0.9 % for LDPE and 2.8 % for PMMA measurements. The time dependence of the temperature response to the input heat flux showed a small drop, which was caused by thermoelastic wave generated by thermal expansions of the heat source.

  18. Vertical axis wind turbine drive train transient dynamics

    NASA Technical Reports Server (NTRS)

    Clauss, D. B.; Carne, T. G.

    1982-01-01

    Start up of a vertical axis wind turbine causes transient torque oscillations in the drive train with peak torques which may be over two and one half times the rated torque of the turbine. A computer code, based on a lumped parameter model of the drive train, was developed and tested for the low cost 17 meter turbine; the results show excellent agreement with field data. The code was used to predict the effect of a slip clutch on transient torque oscillations. It was demonstrated that a slip clutch located between the motor and brake can reduce peak torques by thirty eight percent.

  19. Transient Lift Off Testing Results for a Radial Hybrid Bearing

    DTIC Science & Technology

    2009-05-01

    Speed Hydrostatic Bearings,” ASME Journal of Tribology, Vol. 116, n2, 1994, pp. 337-344. [2] Scharrer, J. K., Tellier , J. and Hibbs, R., “A Study of... Tellier , J. and Hibbs, R., “A Study of the Transient Performance of Hydrostatic Journal Bearings: Part II-Experimental Results,” STLE Paper 91-TC-3B-2...1991. [4] Scharrer, J., Tellier , J. and Hibbs, R., “Start Transient Testing of an Annular Hydrostatic Bearing in Liquid Oxygen,” AIAA Paper 92-3404

  20. Monitoring the Galactic - Search for Hard X-Ray Transients

    NASA Astrophysics Data System (ADS)

    Marshall, Francis

    Hard X-ray transients with fluxs from ~1 to ~30 mCrab are a common feature of the galactic plane with apparent concentrations in specific regions of the plane. Concentrations in the Scutum and Carina fields probably indicate an enhancement of Be X-ray binaries along the tangent direction of two spiral arms. The frequency of outbursts suggest that at any one time 1 or 2 transients are active in the Scutum field alone. We propose weekly scans of the galactic plane to understand this population of sources. The scans will also monitor about 50 already known sources with better spectral information than available with the ASM.

  1. Search for transient gravitational waves in coincidence with short-duration radio transients during 2007-2013

    NASA Astrophysics Data System (ADS)

    Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Behnke, B.; Bejger, M.; Bell, A. S.; Bell, C. J.; Berger, B. K.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bojtos, P.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dattilo, V.; Dave, I.; Daveloza, H. P.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gaur, G.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Holz, D. E.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Idrisy, A.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Islas, G.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Haris, K.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalaidovski, A.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chunglee; Kim, J.; Kim, K.; Kim, Nam-Gyu; Kim, Namjun; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kokeyama, K.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B. M.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Logue, J.; Lombardi, A. L.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lück, H.; Lundgren, A. P.; Luo, J.; Lynch, R.; Ma, Y.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magee, R. M.; Mageswaran, M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mendoza-Gandara, D.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, K. N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nedkova, K.; Nelemans, G.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Pereira, R.; Perreca, A.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Premachandra, S. S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Ricci, F.; Riles, K.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, J. D.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O. E. S.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sentenac, D.; Sequino, V.; Sergeev, A.; Serna, G.; Setyawati, Y.; Sevigny, A.; Shaddock, D. A.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, A. D.; Simakov, D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stiles, D.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D. J.; Whiting, B. F.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Worden, J.; Wright, J. L.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, F.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; Archibald, A. M.; Banaszak, S.; Berndsen, A.; Boyles, J.; Cardoso, R. F.; Chawla, P.; Cherry, A.; Dartez, L. P.; Day, D.; Epstein, C. R.; Ford, A. J.; Flanigan, J.; Garcia, A.; Hessels, J. W. T.; Hinojosa, J.; Jenet, F. A.; Karako-Argaman, C.; Kaspi, V. M.; Keane, E. F.; Kondratiev, V. I.; Kramer, M.; Leake, S.; Lorimer, D.; Lunsford, G.; Lynch, R. S.; Martinez, J. G.; Mata, A.; McLaughlin, M. A.; McPhee, C. A.; Penucci, T.; Ransom, S.; Roberts, M. S. E.; Rohr, M. D. W.; Stairs, I. H.; Stovall, K.; van Leeuwen, J.; Walker, A. N.; Wells, B. L.; LIGO Scientific Collaboration; Virgo Collaboration

    2016-06-01

    We present an archival search for transient gravitational-wave bursts in coincidence with 27 single-pulse triggers from Green Bank Telescope pulsar surveys, using the LIGO, Virgo, and GEO interferometer network. We also discuss a check for gravitational-wave signals in coincidence with Parkes fast radio bursts using similar methods. Data analyzed in these searches were collected between 2007 and 2013. Possible sources of emission of both short-duration radio signals and transient gravitational-wave emission include starquakes on neutron stars, binary coalescence of neutron stars, and cosmic string cusps. While no evidence for gravitational-wave emission in coincidence with these radio transients was found, the current analysis serves as a prototype for similar future searches using more sensitive second-generation interferometers.

  2. Search for Transient Gravitational Waves in Coincidence with Short-Duration Radio Transients During 2007-2013

    NASA Technical Reports Server (NTRS)

    Abbott, B. P.; Hughey, Brennan; Zanolin, Michele; Szczepanczyk, Marek; Gill, Kiranjyot; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; hide

    2016-01-01

    We present an archival search for transient gravitational-wave bursts in coincidence with 27 single-pulse triggers from Green Bank Telescope pulsar surveys, using the LIGO (Laser Interferometer Gravitational Wave Observatory), Virgo (Variability of Solar Irradiance and Gravity Oscillations) and GEO (German-UK Interferometric Detector) interferometer network. We also discuss a check for gravitational-wave signals in coincidence with Parkes fast radio bursts using similar methods. Data analyzed in these searches were collected between 2007 and 2013. Possible sources of emission of both short-duration radio signals and transient gravitational-wave emission include star quakes on neutron stars, binary coalescence of neutron stars, and cosmic string cusps. While no evidence for gravitational-wave emission in coincidence with these radio transients was found, the current analysis serves as a prototype for similar future searches using more sensitive second-generation interferometers.

  3. [Kombinierte Anwendung von Strahlentherapie und adjuvanter Therapie mit einem Mistelextrakt (Viscum album L.) zur Behandlung des oralen malignen Melanoms beim Hund: Eine retrospektive Studie].

    PubMed

    von Bodungen, Uta; Ruess, Katja; Reif, Marcus; Biegel, Ulrike

    2017-01-01

    Hintergrund: Orale maligne Melanome (OMM) des Hundes zeichnen sich durch schnelles Wachstum, lokale Invasion und hohe Metastasierungsraten aus. Extrakte auf Basis von Viscum album L. (VAE) werden zunehmend in der Krebstherapie sowohl in der Human- als auch in der Veterinärmedizin eingesetzt. Ziel unserer Studie war es zu untersuchen, inwieweit die adjuvante Therapie mit VAE eine therapeutische Option zur Behandlung von OMM ist. Besonderes Augenmerk galt dabei der Überlebenszeit und möglichen Nebenwirkungen. Tiere und Methoden: 26 Hunde mit OMM, die in einem der größten veterinäronkologischen Zentren der Schweiz allesamt eine Strahlentherapie erhielten (teilweise nach operativer Tumorresektion) wurden in die retrospektive Studie eingeschlossen: 18 Hunde wurden mit VAE behandelt (1 ml VAE (Iscador®) in ansteigenden Konzentrationen von 0,1 bis 20 mg/ml subkutan 3-mal pro Woche (VAE-Gruppe), 8 erhielten keine adjuvante Behandlung (Vergleichsgruppe). Wir verglichen die Größenentwicklung der OMM sowie die Überlebenszeit. Ergebnisse: Patienten mit Bestrahlung und adjuvanter VAE-Therapie zeigten mit 236 Tagen eine signifikant längere mediane Überlebenszeit im Vergleich zu Patienten mit Bestrahlung, aber ohne adjuvante VAE-Therapie (49 Tage; Log-Rank-Test: p = 0,0047). Die VAE-Therapie verlängerte die Überlebenszeit um mehr als zwei Drittel (Hazard Ratio (HR) = 0,30, 95%-Konfidenzintervall (KI) 0,11-0,86; p = 0,024), während ein höheres Tumorstadium gemäß UICC (Union internationale contre le cancer) einen statistischen Trend zur Verdopplung des Sterberisikos zeigte (UICC-Stadium III/IV vs. I/II: HR = 2,12, 95%-KI 0,88-5,12; p = 0,095). Zwei Patienten zeigten milde Nebenwirkungen während der VAE-Behandlung. Einer der beiden zeigte 1 Tag lang ein selbstlimitiertes Fieber, bei dem anderen Patienten reduzierten wir die Dosis von einem konzentrierteren zu einem weniger konzentrierten VAE (Serie 0) aufgrund von Müdigkeit, die daraufhin verschwand

  4. Transient Potentials in Dendritic Systems of Arbitrary Geometry

    PubMed Central

    Butz, Edward G.; Cowan, Jack D.

    1974-01-01

    A simple graphical calculus is developed that generates analytic solutions for membrane potential transforms at any point on the dendritic tree of neurons with arbitrary dendritic geometries, in response to synaptic “current” inputs. Such solutions permit the computation of transients in neurons with arbitrary geometry and may facilitate analysis of the role of dendrites in such cells. PMID:4416699

  5. Transient potentials in dendritic systems of arbitrary geometry.

    PubMed

    Butz, E G; Cowan, J D

    1974-09-01

    A simple graphical calculus is developed that generates analytic solutions for membrane potential transforms at any point on the dendritic tree of neurons with arbitrary dendritic geometries, in response to synaptic "current" inputs. Such solutions permit the computation of transients in neurons with arbitrary geometry and may facilitate analysis of the role of dendrites in such cells.

  6. Intellectual Deficits After Transient Tyrosinemia in the Term Neonate

    ERIC Educational Resources Information Center

    Mamunes, Peter; And Others

    1976-01-01

    In order to determine if prolonged significant transient neonatal tyrosinemia is injurious to the developing central nervous system, 15 term infants who had suffered from this disorder (involving high blood levels of the amino acid tyrosine) were evaluated. (Author/DB)

  7. Preliminary study of injection transients in the TPS storage ring

    NASA Astrophysics Data System (ADS)

    Chen, C. H.; Liu, Y. C.; Y Chen, J.; Chiu, M. S.; Tseng, F. H.; Fann, S.; Liang, C. C.; Huang, C. S.; Y Lee, T.; Y Chen, B.; Tsai, H. J.; Luo, G. H.; Kuo, C. C.

    2017-07-01

    An optimized injection efficiency is related to a perfect match between the pulsed magnetic fields in the storage ring and transfer line extraction in the TPS. However, misalignment errors, hardware output errors and leakage fields are unavoidable. We study the influence of injection transients on the stored TPS beam and discuss solutions to compensate these. Related simulations and measurements will be presented.

  8. Understanding of Particle Acceleration by Foreshock Transients (invited)

    NASA Astrophysics Data System (ADS)

    Liu, T. Z.; Angelopoulos, V.; Hietala, H.; Lu, S.; Wilson, L. B., III

    2017-12-01

    Although plasma shocks are known to be a major particle accelerator at Earth's environment (e.g., the bow shock) and elsewhere in the universe, how particles are accelerated to very large energies compared to the shock potential is still not fully understood. Significant new information on such acceleration in the vicinity of Earth's bow shock has recently emerged due to the availability of multi-point observations, in particular from Cluster and THEMIS. These have revealed numerous types of foreshock transients, formed by shock-reflected ions, which could play a crucial role in particle pre-acceleration, i.e. before the particles reach the shock to be subjected again to even further acceleration. Foreshock bubbles (FBs) and hot flow anomalies (HFAs), are a subset of such foreshock transients that are especially important due to their large spatial scale (1-10 Earth radii), and their ability to have global effects at Earth.s geospace. These transients can accelerate particles that can become a particle source for the parent shock. Here we introduce our latest progress in understanding particle acceleration by foreshock transients including their statistical characteristics and acceleration mechanisms.

  9. Rural Transient Children and School Achievement: An Australian Perspective.

    ERIC Educational Resources Information Center

    Birch, Ian; Lally, Mike

    1994-01-01

    Among 336 students aged 4-8 in 4 rural Australian schools, transient students scored marginally lower on ability tests than their residentially stable peers. However, teachers gave more weight to family background and support, as opposed to disruption of schooling, as influencing children's adjustment to change and school achievement. (LP)

  10. Experimental Study of Hydraulic Systems Transient Response Characteristics

    DTIC Science & Technology

    1978-12-01

    of Filter .. ... ...... ..... ..... 28 Effects of Quincke -Tube. .. ..... ...... ... 28 Error ’Estimation. .. ... ...... ..... ..... 33 I. CONCLUSIONS...System With Quincke -Tube i Configuration ..... ..................... ... 11 6 Schematic of Pump System .... ............... ... 12 7 Example of Computer...Filter Configuration ........ ..................... 32 20 Transient Response, Reservoir System, Quincke -Tube (Short) Configuration, 505 PSIA

  11. Automated transient identification in the Dark Energy Survey

    SciT

    Goldstein, D. A.

    2015-08-20

    We describe an algorithm for identifying point-source transients and moving objects on reference-subtracted optical images containing artifacts of processing and instrumentation. The algorithm makes use of the supervised machine learning technique known as Random Forest. We present results from its use in the Dark Energy Survey Supernova program (DES-SN), where it was trained using a sample of 898,963 signal and background events generated by the transient detection pipeline. After reprocessing the data collected during the first DES-SN observing season (2013 September through 2014 February) using the algorithm, the number of transient candidates eligible for human scanning decreased by a factormore » of 13.4, while only 1.0 percent of the artificial Type Ia supernovae (SNe) injected into search images to monitor survey efficiency were lost, most of which were very faint events. Here we characterize the algorithm's performance in detail, and we discuss how it can inform pipeline design decisions for future time-domain imaging surveys, such as the Large Synoptic Survey Telescope and the Zwicky Transient Facility.« less

  12. Automated transient identification in the Dark Energy Survey

    DOE PAGES

    Goldstein, D. A.; D'Andrea, C. B.; Fischer, J. A.; ...

    2015-09-01

    We describe an algorithm for identifying point-source transients and moving objects on reference-subtracted optical images containing artifacts of processing and instrumentation. The algorithm makes use of the supervised machine learning technique known as Random Forest. We present results from its use in the Dark Energy Survey Supernova program (DES-SN), where it was trained using a sample of 898,963 signal and background events generated by the transient detection pipeline. After reprocessing the data collected during the first DES-SN observing season (2013 September through 2014 February) using the algorithm, the number of transient candidates eligible for human scanning decreased by a factormore » of 13.4, while only 1.0% of the artificial Type Ia supernovae (SNe) injected into search images to monitor survey efficiency were lost, most of which were very faint events. Furthermore, we characterize the algorithm's performance in detail, and we discuss how it can inform pipeline design decisions for future time-domain imaging surveys, such as the Large Synoptic Survey Telescope and the Zwicky Transient Facility.« less

  13. Recurrent and Transient Spinal Pain Among Commercial Helicopter Pilots.

    PubMed

    Andersen, Knut; Baardsen, Roald; Dalen, Ingvild; Larsen, Jan Petter

    2015-11-01

    The aim of this study was to provide information on the occurrence of spinal pain, i.e., low back and neck pain, among commercial helicopter pilots, along with possible associations between pain and anthropometric and demographic factors and flying exposure. Data were collected through a subjective and retrospective survey among all the 313 (294 men, 19 women) full-time pilots employed by two helicopter companies. A questionnaire was used to assess the extent of spinal complaints in a transient and recurrent pain pattern along with information on physical activities, occupational flying experience, and airframes. The survey had 207 responders (194 men, 13 women). The pilots had extensive flying experience. Spinal pain was reported by 67%. Flying-related transient pain was reported among 50%, whereas recurrent spinal pain, not necessarily associated with flying, was reported by 52%. Women experienced more pain, but sample size prevented further conclusions. Male pilots reporting any spinal pain flew significantly more hours last year (median 500 h, IQR 400-650) versus men with no pain (median 445 h, IQR 300-550). Male pilots with transient or recurrent spinal pain did not differ from nonaffected male colleagues in the measured parameters. Spinal pain is a frequent problem among male and female commercial helicopter pilots. For men, no significant associations were revealed for transient or recurrent spinal pain with age, flying experience in years, total hours, annual flying time, type of aircraft, or anthropometric factors except for any spinal pain related to hours flown in the last year.

  14. Field induced transient current in one-dimensional nanostructure

    NASA Astrophysics Data System (ADS)

    Sako, Tokuei; Ishida, Hiroshi

    2018-07-01

    Field-induced transient current in one-dimensional nanostructures has been studied by a model of an electron confined in a 1D attractive Gaussian potential subjected both to electrodes at the terminals and to an ultrashort pulsed oscillatory electric field with the central frequency ω and the FWHM pulse width Γ. The time-propagation of the electron wave packet has been simulated by integrating the time-dependent Schrödinger equation directly relying on the second-order symplectic integrator method. The transient current has been calculated as the flux of the probability density of the escaping wave packet emitted from the downstream side of the confining potential. When a static bias-field E0 is suddenly applied, the resultant transient current shows an oscillatory decay behavior with time followed by a minimum structure before converging to a nearly constant value. The ω-dependence of the integrated transient current induced by the pulsed electric field has shown an asymmetric resonance line-shape for large Γ while it shows a fringe pattern on the spectral line profile for small Γ. These observations have been rationalized on the basis of the energy-level structure and lifetime of the quasibound states in the bias-field modified confining potential obtained by the complex-scaling Fourier grid Hamiltonian method.

  15. Transient and Dynamic Stability Analysis | Grid Modernization | NREL

    are investigating the impact of high penetrations of wind and solar power on the frequency response ) Transient Stability and Frequency Response of the US Western Interconnection under Conditions of High Wind Subcontract Report (2013) Frequency Response of the US Eastern Interconnection under Condition of High Wind

  16. Transient pseudohypoaldosteronism in infancy secondary to urinary tract infection.

    PubMed

    Abraham, Mary B; Larkins, Nicholas; Choong, Catherine S; Shetty, Vinutha B

    2017-05-01

    Hyponatraemia with hyperkalaemia in infancy is a typical presentation of congenital adrenal hyperplasia. In the presence of pyelonephritis, the same biochemical picture can occur with transient type 1 pseudohypoaldosteronism (PHA-1) also termed type 4 renal tubular acidosis. Recognition of PHA-1 enables appropriate management thus avoiding unnecessary investigations and treatment. To improve awareness of this condition, we present a case series to highlight the clinical and biochemical features of PHA-1. A retrospective chart review of patients diagnosed with transient PHA-1 at a tertiary children's hospital in Western Australia was conducted. Five male infants (32 days to 6 months) with transient PHA-1 were identified. Failure to thrive was the most common symptom with hyponatraemia on presentation. Two infants had antenatally diagnosed bilateral hydronephrosis and urinary tract infection (UTI) on admission. Two infants were treated for congenital adrenal hyperplasia and received hydrocortisone. All infants had UTI and required parenteral antibiotics. The condition was transient and hyponatraemia corrected by day 4 in all infants. There was no correlation between plasma sodium and aldosterone levels. The severity of PHA-1 was independent of the underlying renal anomaly. Four infants had hydronephrosis and vesicoureteric reflux. Surgical intervention was required in two infants. PHA-1 may be precipitated by UTI or urinary tract anomalies in early infancy. Urine analysis should be performed in infants with hyponatraemia. Diagnosis of PHA-1 facilitates appropriate renal investigations to reduce long-term morbidity. © 2017 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).

  17. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate... cycles. The heavy-duty transient engine cycles for Otto-cycle and diesel engines are listed in appendix I...

  18. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate... cycles. The heavy-duty transient engine cycles for Otto-cycle and diesel engines are listed in appendix I...

  19. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate... cycles. The heavy-duty transient engine cycles for Otto-cycle and diesel engines are listed in appendix I...

  20. Automated Transient Identification in the Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Goldstein, D. A.; D'Andrea, C. B.; Fischer, J. A.; Foley, R. J.; Gupta, R. R.; Kessler, R.; Kim, A. G.; Nichol, R. C.; Nugent, P. E.; Papadopoulos, A.; Sako, M.; Smith, M.; Sullivan, M.; Thomas, R. C.; Wester, W.; Wolf, R. C.; Abdalla, F. B.; Banerji, M.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Carnero Rosell, A.; Castander, F. J.; da Costa, L. N.; Covarrubias, R.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Eifler, T. F.; Fausti Neto, A.; Finley, D. A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D.; Gruen, D.; Gruendl, R. A.; James, D.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Maia, M. A. G.; Makler, M.; March, M.; Marshall, J. L.; Martini, P.; Merritt, K. W.; Miquel, R.; Nord, B.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Roodman, A.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Walker, A. R.

    2015-09-01

    We describe an algorithm for identifying point-source transients and moving objects on reference-subtracted optical images containing artifacts of processing and instrumentation. The algorithm makes use of the supervised machine learning technique known as Random Forest. We present results from its use in the Dark Energy Survey Supernova program (DES-SN), where it was trained using a sample of 898,963 signal and background events generated by the transient detection pipeline. After reprocessing the data collected during the first DES-SN observing season (2013 September through 2014 February) using the algorithm, the number of transient candidates eligible for human scanning decreased by a factor of 13.4, while only 1.0% of the artificial Type Ia supernovae (SNe) injected into search images to monitor survey efficiency were lost, most of which were very faint events. Here we characterize the algorithm’s performance in detail, and we discuss how it can inform pipeline design decisions for future time-domain imaging surveys, such as the Large Synoptic Survey Telescope and the Zwicky Transient Facility. An implementation of the algorithm and the training data used in this paper are available at at http://portal.nersc.gov/project/dessn/autoscan.

  1. Spectroscopic Classifications of Optical Transients with Keck I/LRIS

    NASA Astrophysics Data System (ADS)

    Foley, R. J.; Rojas-Bravo, C.

    2018-05-01

    We report the following classifications of optical transients from spectroscopic observations with LRIS on the Keck I 10-m telescope. Targets were supplied by the ASAS-SN and PSH. All observations were made on 2018 May 10 UT. Classifications were performed with SNID (Blondin & Tonry, 2007, ApJ, 666, 1024).

  2. Small gravitationally elicited voltage transients in pea stems

    NASA Technical Reports Server (NTRS)

    Pickard, B. G.

    1984-01-01

    Decapitated veritcal stem segments were observed for 45 min, noting the number of transients mu V for each 5-min interval. Results for two sets of stem segments are plotted. The average frequencies were 0.72 + or -0.05 and 0.66 + or - 0.04 per 5 min. One set of segments was swiveled gently to the horizontal position; then, recording continued for another 90 min. Transients continued in the vertical controls at a closely similar average rate 0.78 + or - 0.04 per 5 min. However, after the first 5-min interval the horizontally placed plants exhibited transients at an increased average rate of 1.08 + or - 0.04 per 5 min. The frequency of transients also increased following horizontal placement of intact shoots. However, it appears that this increase had two components: one due to gravity reception, and one due to the redistribution of indolacetic acid (IAA) believed to mediate gravitropic curvature (or, more specifically, to the increase of IAA in the lower tissue.

  3. Transient global amnesia after taking sibutramine: a case report.

    PubMed

    Fu, Pin-Kuei; Hsu, Hung-Yi; Wang, Pao-Yu

    2010-03-01

    Sibutramine (Meridia in the United States, Reductil in Europe) is approved for weight reduction and weight maintenance. Although amnesia and seizure is listed as a reported adverse event of sibutramine in the US product information, our literature search in the PubMed website database found no published reports of theses adverse events. We report a 39-year-old healthy woman who had an episode of sudden memory loss lasting for several hours after taking sibutramine for 4 days. Cranial computed tomography scan, magnetic resonance imaging, and magnetic resonance angiography of the head all showed normal results. Electroencephalogram showed spike and wave complexes with phase reversal in the left mesial temporal area. Transient global amnesia was suspected clinically and transient epileptic amnesia provoked by sibutramine was also proposed. Three months after this episode, the follow-up electroencephalogram was normal. This patient did not take any anticonvulsant, and there were no more episodes of memory impairment. This case serves to emphasize that sibutramine which was used for weight reduction might induce transient global amnesia or provoke transient epileptic amnesia. Physicians should be careful to monitor for this adverse effect when sibutramine is prescribed.

  4. Can we observe neutrino flares in coincidence with explosive transients?

    NASA Astrophysics Data System (ADS)

    Guépin, C.; Kotera, K.

    2017-12-01

    The new generation of powerful instruments is reaching sensitivities and temporal resolutions that will allow multi-messenger astronomy of explosive transient phenomena, with high-energy neutrinos as a central figure. We derive general criteria for the detectability of neutrinos from powerful transient sources for given instrument sensitivities. In practice, we provide the minimum photon flux necessary for neutrino detection based on two main observables: the bolometric luminosity and the time variability of the emission. This limit can be compared to the observations in specified wavelengths in order to target the most promising sources for follow-ups. Our criteria can also help distinguishing false associations of neutrino events with a flaring source. We find that relativistic transient sources such as high- and low-luminosity gamma-ray bursts (GRBs), blazar flares, tidal disruption events, and magnetar flares could be observed with IceCube, as they have a good chance to occur within a detectable distance. Of the nonrelativistic transient sources, only luminous supernovae appear as promising candidates. We caution that our criterion should not be directly applied to low-luminosity GRBs and type Ibc supernovae, as these objects could have hosted a choked GRB, leading to neutrino emission without a relevant counterpart radiation. We treat the concrete example of PKS 1424-418 major outburst and the possible association with an IceCube event IC 35.

  5. Novae as a Class of Transient X-ray Sources

    NASA Technical Reports Server (NTRS)

    Mukai, K.; Orio, M.; Valle, M. Della

    2007-01-01

    Motivated by the recently discovered class of faint (10(exp 34)-10(exp 35) ergs/s) X-ray transients in the Galactic Center region, we investigate the 2-10 keV properties of classical and recurrent novae. Existing data are consistent with the idea that all classical novae are transient X-ray sources with durations of months to years and peak luminosities in the 10(exp 34)-10(exp 35)ergs/s range. This makes classical novae a viable candidate class for the faint Galactic Center transients. We estimate the rate of classical novae within a 15 arcmin radius region centered on the Galactic Center (roughly the field of view of XMM-Newton observations centered on Sgr A*) to be approx.0.1 per year. Therefore, it is plausible that some of the Galactic Center transients that have been announced to date are unrecognized classical novae. The continuing monitoring of the Galactic Center region carried out by Chandra and XMM-Newton may therefore provide a new method to detect classical novae in this crowded and obscured region, an

  6. Performance Enhancement of the NPS Transient Electromagnetic Scattering Laboratory

    DTIC Science & Technology

    1991-09-01

    MASTER OF SCIENCE IN ELECTRICAL ENGINEERING MASTER OF SCIENCE IN SYSTEMS ENGINEERING (ELECTRONIC WARFARE) from NAVAL POSTGRADUATE S OOL Author: JvAlo...Bresani Approved by: Michael A. Morgan, Thesis Advisor Jeffrey B. Knorr, Second Reader Michael A. Morgan, Chairman, Department of Electrical & Computer...SYSTEM REPRESENTATION ... .......... 13 B. MATHEMATICAL MODEL ......... ..... 15 C. TRANSIENT RESPONSE EVALUATION .. ......... . 17 IV. MEASUREMENT

  7. Languages without Borders: TESOL in a Transient World

    ERIC Educational Resources Information Center

    Nero, Shondel

    2012-01-01

    In today's transient world, where a continual multidirectional flow of people, goods, and services has deterritorialized languages and their users, languages, especially English, are now without borders. In this context, English language teaching (ELT) as a profession is called to a new task. In this article, I examine this task by asking the…

  8. Intelligent transient transitions detection of LRE test bed

    NASA Astrophysics Data System (ADS)

    Zhu, Fengyu; Shen, Zhengguang; Wang, Qi

    2013-01-01

    Health Monitoring Systems is an implementation of monitoring strategies for complex systems whereby avoiding catastrophic failure, extending life and leading to improved asset management. A Health Monitoring Systems generally encompasses intelligence at many levels and sub-systems including sensors, actuators, devices, etc. In this paper, a smart sensor is studied, which is use to detect transient transitions of liquid-propellant rocket engines test bed. In consideration of dramatic changes of variable condition, wavelet decomposition is used to work real time in areas. Contrast to traditional Fourier transform method, the major advantage of adding wavelet analysis is the ability to detect transient transitions as well as obtaining the frequency content using a much smaller data set. Historically, transient transitions were only detected by offline analysis of the data. The methods proposed in this paper provide an opportunity to detect transient transitions automatically as well as many additional data anomalies, and provide improved data-correction and sensor health diagnostic abilities. The developed algorithms have been tested on actual rocket test data.

  9. Parametric Thermal Models of the Transient Reactor Test Facility (TREAT)

    SciT

    Bradley K. Heath

    2014-03-01

    This work supports the restart of transient testing in the United States using the Department of Energy’s Transient Reactor Test Facility at the Idaho National Laboratory. It also supports the Global Threat Reduction Initiative by reducing proliferation risk of high enriched uranium fuel. The work involves the creation of a nuclear fuel assembly model using the fuel performance code known as BISON. The model simulates the thermal behavior of a nuclear fuel assembly during steady state and transient operational modes. Additional models of the same geometry but differing material properties are created to perform parametric studies. The results show thatmore » fuel and cladding thermal conductivity have the greatest effect on fuel temperature under the steady state operational mode. Fuel density and fuel specific heat have the greatest effect for transient operational model. When considering a new fuel type it is recommended to use materials that decrease the specific heat of the fuel and the thermal conductivity of the fuel’s cladding in order to deal with higher density fuels that accompany the LEU conversion process. Data on the latest operating conditions of TREAT need to be attained in order to validate BISON’s results. BISON’s models for TREAT (material models, boundary convection models) are modest and need additional work to ensure accuracy and confidence in results.« less

  10. Screening promoters for Anthurium transformation using transient expression

    Different promoters and tissue types were evaluated for transient '-glucoronidase (GUS) expression in Anthurium andreanum Hort. ‘Marian Seefurth’ following microprojectile bombardment. Plasmids containing the Ubiquitin 2, Actin 1, Cytochrome C1 from rice, Ubiquitin 1 from maize and 35 S promoter fr...

  11. Research on radiation detectors, boiling transients, and organic lubricants

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The accomplishments of a space projects research facility are presented. The subjects discussed are: (1) a study of radiation resistant semiconductor devices, (2) synthesis of high temperature organic lubricants, (3) departure from phase equilibrium during boiling transients, (4) effects of neutron irradiation on defect state in tungsten, and (5) determination of photon response function of NE-213 liquid scintillation detectors.

  12. Influence of transient flooding on methane fluxes from subtropical pastures

    Seasonally flooded subtropical pastures are major methane (CH4) sources, where transient flooding drives episodic and high-magnitude emissions from the underlying landscape. Understanding the mechanisms that drive these patterns is needed to better understand pasture CH4 emissions and their response...

  13. MINIMIZATION OF TRANSIENT EMISSIONS FROM ROTARY KILN INCINERATORS

    EPA Science Inventory

    Transient emissions of organics can occur from rotary kiln incinerators when drums containing liquid wastes bound on sorbents are introduced in a batch-wise fashion. Physical processes controlling the release of waste from the sorbent material are greatly affected by the rotation...

  14. Palomar 60-inch SEDM classification of optical transients

    NASA Astrophysics Data System (ADS)

    Fremling, Christoffer; Blagorodnova, Nadejda; Kupfer, Thomas; Neill, James D.; Walters, Richard; Cannella, Christopher B.; Kulkarni, Shrinivas R.

    2018-04-01

    We report the classification of the following bright transients. The spectra have been obtained with the Spectral Energy Distribution Machine (SEDM) (range 350-950nm, spectral resolution R 100) mounted on the Palomar 60-inch (P60) telescope (Blagorodnova et. al. 2018, PASP, 130, 5003).

  15. Palomar 60-inch SEDM classification of optical transients

    NASA Astrophysics Data System (ADS)

    Fremling, Christoffer; Blagorodnova, Nadejda; Neill, James D.; Walters, Richard; Cannella, Christopher B.; Kulkarni, Shrinivas R.

    2018-03-01

    We report the classification of the following bright transients. The spectra have been obtained with the Spectral Energy Distribution Machine (SEDM) (range 350-950nm, spectral resolution R 100) mounted on the Palomar 60-inch (P60) telescope (Blagorodnova et. al. 2018).

  16. Palomar 60-inch SEDM classification of optical transients

    NASA Astrophysics Data System (ADS)

    Blagorodnova, Nadejda; Fremling, Christoffer; Neill, James D.; Walters, Richard; Cannella, Christopher B.; Kulkarni, Shrinivas R.

    2018-03-01

    We report the classification of the following bright transients. The spectra have been obtained with the Spectral Energy Distribution Machine (SEDM) (range 350-950nm, spectral resolution R 100) mounted on the Palomar 60-inch (P60) telescope (Blagorodnova et. al. 2018, PASP, 130, 5003).

  17. Transient Structured Distance as a Maneuver in Marital Therapy

    ERIC Educational Resources Information Center

    Greene, Bernard L.; And Others

    1973-01-01

    Experience with 73 cases has shown the value of Transient Structured Distance as a maneuver in marriage therapy. While the TSD is a radical form of intervention with risks of anxiety reactions, homosexual panic, or divorce, it has proved effective with difficult forms of acute or chronic marital disharmony. (Author)

  18. Transient Modeling of Hybrid Rocket Low Frequency Instabilities

    NASA Technical Reports Server (NTRS)

    Karabeyoglu, M. Arif; DeZilwa, Shane; Cantwell, Brian; Zilliac, Greg

    2003-01-01

    A comprehensive dynamic model of a hybrid rocket has been developed in order to understand and predict the transient behavior including instabilities. A linearized version of the transient model predicted the low-frequency chamber pressure oscillations that are commonly observed in hybrids. The source of the instabilities is based on a complex coupling of thermal transients in the solid fuel, wall heat transfer blocking due to fuel regression rate and the transients in the boundary layer that forms on the fuel surface. The oscillation frequencies predicted by the linearized theory are in very good agreement with 43 motor test results obtained from the hybrid propulsion literature. The motor test results used in the comparison cover a very wide spectrum of parameters including: 1) four separate research and development programs, 2) three different oxidizers (LOX, GOX, N2O), 3) a wide range of motor dimensions (i.e. from 5 inch diameter to 72 inch diameter) and operating conditions and 4) several fuel formulations. A simple universal scaling formula for the frequency of the primary oscillation mode is suggested.

  19. TRANSIENT SUPPRESSION PACKAGING FOR REDUCED EMISSIONS FROM ROTARY KILN INCINERATORS

    EPA Science Inventory

    Experiments were performed on a 73 kW rotary kiln incinerator simulator to determine whether innovative waste packaging designs might reduce transient emissions of products of incomplete combustion due to batch charging of containerized liquid surrogate waste compounds bound on g...

  20. RADIO TRANSIENTS FROM ACCRETION-INDUCED COLLAPSE OF WHITE DWARFS

    SciT

    Moriya, Takashi J., E-mail: takashi.moriya@nao.ac.jp

    2016-10-20

    We investigate observational properties of accretion-induced collapse (AIC) of white dwarfs (WDs) in radio frequencies. If AIC is triggered by accretion from a companion star, a dense circumstellar medium can be formed around the progenitor system. Then, the ejecta from AIC collide with the dense circumstellar medium, creating a strong shock. The strong shock can produce synchrotron emission that can be observed in radio frequencies. Even if AIC occurs as a result of WD mergers, we argue that AIC may cause fast radio bursts (FRBs) if a certain condition is satisfied. If AIC forms neutron stars (NSs) that are somore » massive that rotation is required to support themselves (i.e., supramassive NSs), the supramassive NSs may immediately lose their rotational energy by the r-mode instability and collapse to black holes. If the collapsing supramassive NSs are strongly magnetized, they may emit FRBs, as previously proposed. The AIC radio transients from single-degenerate systems may be detected in future radio transient surveys like the Very Large Array Sky Survey or the Square Kilometer Array transient survey. Because AIC has been proposed as a source of gravitational waves (GWs), GWs from AIC may be accompanied by radio-bright transients that can be used to confirm the AIC origin of observed GWs.« less

  1. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Kilpatrick, C. D.; Pan, Y.-C.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2017-01-01

    We report the following classifications of optical transients from spectroscopic observations with KOSMOS on the KPNO Mayall 4-m telescope. Targets were supplied by the All-Sky Automated Survey for Supernovae (ASAS-SN) and the ATLAS project (ATel #8680).

  2. The SED Machine: A Robotic Spectrograph for Fast Transient Classification

    NASA Astrophysics Data System (ADS)

    Blagorodnova, Nadejda; Neill, James D.; Walters, Richard; Kulkarni, Shrinivas R.; Fremling, Christoffer; Ben-Ami, Sagi; Dekany, Richard G.; Fucik, Jason R.; Konidaris, Nick; Nash, Reston; Ngeow, Chow-Choong; Ofek, Eran O.; O’ Sullivan, Donal; Quimby, Robert; Ritter, Andreas; Vyhmeister, Karl E.

    2018-03-01

    Current time domain facilities are finding several hundreds of transient astronomical events a year. The discovery rate is expected to increase in the future as soon as new surveys such as the Zwicky Transient Facility (ZTF) and the Large Synoptic Sky Survey (LSST) come online. Presently, the rate at which transients are classified is approximately one order or magnitude lower than the discovery rate, leading to an increasing “follow-up drought”. Existing telescopes with moderate aperture can help address this deficit when equipped with spectrographs optimized for spectral classification. Here, we provide an overview of the design, operations and first results of the Spectral Energy Distribution Machine (SEDM), operating on the Palomar 60-inch telescope (P60). The instrument is optimized for classification and high observing efficiency. It combines a low-resolution (R ∼ 100) integral field unit (IFU) spectrograph with “Rainbow Camera” (RC), a multi-band field acquisition camera which also serves as multi-band (ugri) photometer. The SEDM was commissioned during the operation of the intermediate Palomar Transient Factory (iPTF) and has already lived up to its promise. The success of the SEDM demonstrates the value of spectrographs optimized for spectral classification.

  3. Design of transient light signal simulator based on FPGA

    NASA Astrophysics Data System (ADS)

    Kang, Jing; Chen, Rong-li; Wang, Hong

    2014-11-01

    A design scheme of transient light signal simulator based on Field Programmable gate Array (FPGA) was proposed in this paper. Based on the characteristics of transient light signals and measured feature points of optical intensity signals, a fitted curve was created in MATLAB. And then the wave data was stored in a programmed memory chip AT29C1024 by using SUPERPRO programmer. The control logic was realized inside one EP3C16 FPGA chip. Data readout, data stream cache and a constant current buck regulator for powering high-brightness LEDs were all controlled by FPGA. A 12-Bit multiplying CMOS digital-to-analog converter (DAC) DAC7545 and an amplifier OPA277 were used to convert digital signals to voltage signals. A voltage-controlled current source constituted by a NPN transistor and an operational amplifier controlled LED array diming to achieve simulation of transient light signal. LM3405A, 1A Constant Current Buck Regulator for Powering LEDs, was used to simulate strong background signal in space. Experimental results showed that the scheme as a transient light signal simulator can satisfy the requests of the design stably.

  4. Separation of distinct photoexcitation species in femtosecond transient absorption microscopy

    DOE PAGES

    Xiao, Kai; Ma, Ying -Zhong; Simpson, Mary Jane; ...

    2016-02-03

    Femtosecond transient absorption microscopy is a novel chemical imaging capability with simultaneous high spatial and temporal resolution. Although several powerful data analysis approaches have been developed and successfully applied to separate distinct chemical species in such images, the application of such analysis to distinguish different photoexcited species is rare. In this paper, we demonstrate a combined approach based on phasor and linear decomposition analysis on a microscopic level that allows us to separate the contributions of both the excitons and free charge carriers in the observed transient absorption response of a composite organometallic lead halide perovskite film. We found spatialmore » regions where the transient absorption response was predominately a result of excitons and others where it was predominately due to charge carriers, and regions consisting of signals from both contributors. Lastly, quantitative decomposition of the transient absorption response curves further enabled us to reveal the relative contribution of each photoexcitation to the measured response at spatially resolved locations in the film.« less

  5. An unusually brilliant transient in the galaxy M85.

    PubMed

    Kulkarni, S R; Ofek, E O; Rau, A; Cenko, S B; Soderberg, A M; Fox, D B; Gal-Yam, A; Capak, P L; Moon, D S; Li, W; Filippenko, A V; Egami, E; Kartaltepe, J; Sanders, D B

    2007-05-24

    Historically, variable and transient sources have both surprised astronomers and provided new views of the heavens. Here we report the discovery of an optical transient in the outskirts of the lenticular galaxy Messier 85 in the Virgo cluster. With a peak absolute R magnitude of -12, this event is distinctly brighter than novae, but fainter than type Ia supernovae (which are expected in a population of old stars in lenticular galaxies). Archival images of the field do not show a luminous star at that position with an upper limit in the g filter of about -4.1 mag, so it is unlikely to be a giant eruption from a luminous blue variable star. Over a two-month period, the transient source emitted radiation energy of almost 10(47) erg and subsequently faded in the optical sky. It is similar to, but six times more luminous at peak than, an enigmatic transient in the galaxy M31 (ref. 1). A possible origin of M85 OT2006-1 is a stellar merger. If so, searches for similar events in nearby galaxies will not only allow study of the physics of hyper-Eddington sources, but also probe an important phase in the evolution of stellar binary systems.

  6. One-dimensional transient radiative transfer by lattice Boltzmann method.

    PubMed

    Zhang, Yong; Yi, Hongliang; Tan, Heping

    2013-10-21

    The lattice Boltzmann method (LBM) is extended to solve transient radiative transfer in one-dimensional slab containing scattering media subjected to a collimated short laser irradiation. By using a fully implicit backward differencing scheme to discretize the transient term in the radiative transfer equation, a new type of lattice structure is devised. The accuracy and computational efficiency of this algorithm are examined firstly. Afterwards, effects of the medium properties such as the extinction coefficient, the scattering albedo and the anisotropy factor, and the shapes of laser pulse on time-resolved signals of transmittance and reflectance are investigated. Results of the present method are found to compare very well with the data from the literature. For an oblique incidence, the LBM results in this paper are compared with those by Monte Carlo method generated by ourselves. In addition, transient radiative transfer in a two-Layer inhomogeneous media subjected to a short square pulse irradiation is investigated. At last, the LBM is further extended to study the transient radiative transfer in homogeneous medium with a refractive index discontinuity irradiated by the short pulse laser. Several trends on the time-resolved signals different from those for refractive index of 1 (i.e. refractive-index-matched boundary) are observed and analysed.

  7. Transient Simulation of the Multi-SERTTA Experiment with MAMMOTH

    SciT

    Ortensi, Javier; Baker, Benjamin; Wang, Yaqi

    This work details the MAMMOTH reactor physics simulations of the Static Environment Rodlet Transient Test Apparatus (SERTTA) conducted at Idaho National Laboratory in FY-2017. TREAT static-environment experiment vehicles are being developed to enable transient testing of Pressurized Water Reactor (PWR) type fuel specimens, including fuel concepts with enhanced accident tolerance (Accident Tolerant Fuels, ATF). The MAMMOTH simulations include point reactor kinetics as well as spatial dynamics for a temperature-limited transient. The strongly coupled multi-physics solutions of the neutron flux and temperature fields are second order accurate both in the spatial and temporal domains. MAMMOTH produces pellet stack powers that are within 1.5% of the Monte Carlo reference solutions. Some discrepancies between the MCNP model used in the design of the flux collars and the Serpent/MAMMOTH models lead to higher power and energy deposition values in Multi-SERTTA unit 1. The TREAT core results compare well with the safety case computed with point reactor kinetics in RELAP5-3D. The reactor period is 44 msec, which corresponds to a reactivity insertion of 2.685% delta k/kmore » $. The peak core power in the spatial dynamics simulation is 431 MW, which the point kinetics model over-predicts by 12%. The pulse width at half the maximum power is 0.177 sec. Subtle transient effects are apparent at the beginning insertion in the experimental samples due to the control rod removal. Additional difference due to transient effects are observed in the sample powers and enthalpy. The time dependence of the power coupling factor (PCF) is calculated for the various fuel stacks of the Multi-SERTTA vehicle. Sample temperatures in excess of 3100 K, the melting point UO$$_2$$, are computed with the adiabatic heat transfer model. The planned shaped-transient might introduce additional effects that cannot be predicted with PRK models. Future modeling will be focused on the shaped-transient by

  8. Runaway transient simulation of a model Kaplan turbine

    NASA Astrophysics Data System (ADS)

    Liu, S.; Zhou, D.; Liu, D.; Wu, Y.; Nishi, M.

    2010-08-01

    The runaway transient is a typical transient process of a hydro power unit, where the rotational speed of a turbine runner rapidly increases up to the runaway speed under a working head as the guide vanes cannot be closed due to some reason at the load rejection. In the present paper, the characteristics of the runaway transient of a model Kaplan turbine having ns = 479(m-kW) is simulated by using a time-dependent CFD technique where equation of rotational motion of runner, continuity equation and unsteady RANS equations with RNG k-epsilon turbulence model are solved iteratively. In the calculation, unstructured mesh is used to the whole flow passage, which consists of several sub-domains: entrance, casing, stay vanes + guide vanes, guide section, runner and draft tube. And variable speed sliding mesh technique is used to exchange interface flow information between moving part and stationary part, and three-dimensional unstructured dynamic mesh technique is also adopted to ensure mesh quality. Two cases were treated in the simulation of runaway transient characteristics after load rejection: one is the rated operating condition as the initial condition, and the other is the condition at the maximum head. Regarding the runaway speed, the experimental speed is 1.45 times the initial speed and the calculation is 1.47 times the initial for the former case. In the latter case, the experiment and the calculation are 1.67 times and 1.69 times respectively. From these results, it is recognized that satisfactorily prediction will be possible by using the present numerical method. Further, numerical results show that the swirl in the draft-tube flow becomes stronger in the latter part of the transient process so that a vortex rope will occur in the draft tube and its precession will cause the pressure fluctuations which sometimes affect the stability of hydro power system considerably.

  9. iPTF Archival Search for Fast Optical Transients

    NASA Astrophysics Data System (ADS)

    Ho, Anna Y. Q.; Kulkarni, S. R.; Nugent, Peter E.; Zhao, Weijie; Rusu, Florin; Cenko, S. Bradley; Ravi, Vikram; Kasliwal, Mansi M.; Perley, Daniel A.; Adams, Scott M.; Bellm, Eric C.; Brady, Patrick; Fremling, Christoffer; Gal-Yam, Avishay; Kann, David Alexander; Kaplan, David; Laher, Russ R.; Masci, Frank; Ofek, Eran O.; Sollerman, Jesper; Urban, Alex

    2018-02-01

    There has been speculation about a class of relativistic explosions with an initial Lorentz factor Γinit smaller than that of classical gamma-ray bursts (GRBs). These “dirty fireballs” would lack prompt GRB emission but could be pursued via their optical afterglow, appearing as transients that fade overnight. Here we report a search for such transients (that fade by 5-σ in magnitude overnight) in four years of archival photometric data from the intermediate Palomar Transient Factory (iPTF). Our search criteria yielded 50 candidates. Of these, two were afterglows to GRBs that had been found in dedicated follow-up observations to triggers from the Fermi GRB Monitor. Another (iPTF14yb) was a GRB afterglow discovered serendipitously. Eight were spurious artifacts of reference image subtraction, and one was an asteroid. The remaining 38 candidates have red stellar counterparts in external catalogs. The photometric and spectroscopic properties of the counterparts identify these transients as strong flares from M dwarfs of spectral type M3–M7 at distances of d ≈ 0.15–2.1 kpc; three counterparts were already spectroscopically classified as late-type M stars. With iPTF14yb as the only confirmed relativistic outflow discovered independently of a high-energy trigger, we constrain the all-sky rate of transients that peak at m = 18 and fade by Δm = 2 mag in Δt = 3 hr to be 680 {{yr}}-1, with a 68% confidence interval of 119{--}2236 {{yr}}-1. This implies that the rate of visible dirty fireballs is at most comparable to that of the known population of long-duration GRBs.

  10. MOSFiT: Modular Open Source Fitter for Transients

    NASA Astrophysics Data System (ADS)

    Guillochon, James; Nicholl, Matt; Villar, V. Ashley; Mockler, Brenna; Narayan, Gautham; Mandel, Kaisey S.; Berger, Edo; Williams, Peter K. G.

    2018-05-01

    Much of the progress made in time-domain astronomy is accomplished by relating observational multiwavelength time-series data to models derived from our understanding of physical laws. This goal is typically accomplished by dividing the task in two: collecting data (observing), and constructing models to represent that data (theorizing). Owing to the natural tendency for specialization, a disconnect can develop between the best available theories and the best available data, potentially delaying advances in our understanding new classes of transients. We introduce MOSFiT: the Modular Open Source Fitter for Transients, a Python-based package that downloads transient data sets from open online catalogs (e.g., the Open Supernova Catalog), generates Monte Carlo ensembles of semi-analytical light-curve fits to those data sets and their associated Bayesian parameter posteriors, and optionally delivers the fitting results back to those same catalogs to make them available to the rest of the community. MOSFiT is designed to help bridge the gap between observations and theory in time-domain astronomy; in addition to making the application of existing models and creation of new models as simple as possible, MOSFiT yields statistically robust predictions for transient characteristics, with a standard output format that includes all the setup information necessary to reproduce a given result. As large-scale surveys such as that conducted with the Large Synoptic Survey Telescope (LSST), discover entirely new classes of transients, tools such as MOSFiT will be critical for enabling rapid comparison of models against data in statistically consistent, reproducible, and scientifically beneficial ways.

  11. Role of transients in the sustainability of solar coronal plumes

    SciT

    Raouafi, N.-E.; Stenborg, G., E-mail: NourEddine.Raouafi@jhuapl.edu

    2014-06-01

    We report on the role of small-scale, transient magnetic activity in the formation and evolution of solar coronal plumes. Three plumes within equatorial coronal holes are analyzed over the span of several days based on the Solar Dynamic Observatory (SDO)/Atmospheric Imaging Assembly 171 Å and 193 Å images and SDO/Helioseismic and Magnetic Imager line-of-sight magnetograms. The focus is on the role of transient structures at the footpoints in sustaining coronal plumes for relatively long periods of time (i.e., several days). The appearance of plumes is a gradual and lengthy process. In some cases, the initial stages of plume formation aremore » marked by the appearance of pillar-like structures whose footpoints are the sources of transient brightenings. In addition to nominal jets occurring prior to and during the development of plumes, the data show that a large number of small jets (i.e., {sup j}etlets{sup )} and plume transient bright points (PTBPs) occur on timescales of tens of seconds to a few minutes. These features are the result of quasi-random cancellations of fragmented and diffuse minority magnetic polarity with the dominant unipolar magnetic field concentration over an extended period of time. They unambiguously reflect a highly dynamical evolution at the footpoints and are seemingly the main energy source for plumes. This suggests a tendency for plumes to be dependent on the occurrence of transients (i.e., jetlets, and PTBPs) resulting from low-rate magnetic reconnection. The decay phase of plumes is characterized by gradual fainting and multiple rejuvenations as a result of the dispersal of the unipolar magnetic concentration and its precipitation into multiple magnetic centers.« less

  12. iPTF Archival Search for Fast Optical Transients

    DOE PAGES

    Ho, Anna Y. Q.; Kulkarni, S. R.; Nugent, Peter E.; ...

    2018-02-09

    There has been speculation about a class of relativistic explosions with an initial Lorentz factor Γ init smaller than that of classical gamma-ray bursts (GRBs). These "dirty fireballs" would lack prompt GRB emission but could be pursued via their optical afterglow, appearing as transients that fade overnight. We report a search for such transients (that fade by 5-σ in magnitude overnight) in four years of archival photometric data from the intermediate Palomar Transient Factory (iPTF). Our search criteria yielded 50 candidates. Of these, two were afterglows to GRBs that had been found in dedicated follow-up observations to triggers from themore » Fermi GRB Monitor. Another (iPTF14yb) was a GRB afterglow discovered serendipitously. Eight were spurious artifacts of reference image subtraction, and one was an asteroid. The remaining 38 candidates have red stellar counterparts in external catalogs. The photometric and spectroscopic properties of the counterparts identify these transients as strong flares from M dwarfs of spectral type M3-M7 at distances of d ≈ 0.15-2.1 kpc; three counterparts were already spectroscopically classified as late-type M stars. With iPTF14yb as the only confirmed relativistic outflow discovered independently of a high-energy trigger, we constrain the all-sky rate of transients that peak at m = 18 and fade by Δm = 2 mag in Δt = 3 hr to be 680 yr -1, with a 68% confidence interval of 1119-2236 yr -1. This implies that the rate of visible dirty fireballs is at most comparable to that of the known population of long-duration GRBs.« less

  13. Short-term depression and transient memory in sensory cortex.

    PubMed

    Gillary, Grant; Heydt, Rüdiger von der; Niebur, Ernst

    2017-12-01

    Persistent neuronal activity is usually studied in the context of short-term memory localized in central cortical areas. Recent studies show that early sensory areas also can have persistent representations of stimuli which emerge quickly (over tens of milliseconds) and decay slowly (over seconds). Traditional positive feedback models cannot explain sensory persistence for at least two reasons: (i) They show attractor dynamics, with transient perturbations resulting in a quasi-permanent change of system state, whereas sensory systems return to the original state after a transient. (ii) As we show, those positive feedback models which decay to baseline lose their persistence when their recurrent connections are subject to short-term depression, a common property of excitatory connections in early sensory areas. Dual time constant network behavior has also been implemented by nonlinear afferents producing a large transient input followed by much smaller steady state input. We show that such networks require unphysiologically large onset transients to produce the rise and decay observed in sensory areas. Our study explores how memory and persistence can be implemented in another model class, derivative feedback networks. We show that these networks can operate with two vastly different time courses, changing their state quickly when new information is coming in but retaining it for a long time, and that these capabilities are robust to short-term depression. Specifically, derivative feedback networks with short-term depression that acts differentially on positive and negative feedback projections are capable of dynamically changing their time constant, thus allowing fast onset and slow decay of responses without requiring unrealistically large input transients.

  14. [Assessment of parental stress using the "Eltern-Belastungs-Screening zur Kindeswohlgefährdung" (EBSK) - association with emotional and behavioral problems in children].

    PubMed

    Eichler, Anna K; Glaubitz, Katharina A; Hartmann, Luisa C; Spangler, Gottfried

    2014-07-01

    Parental stress is increased in clinical contexts (e.g., child psychiatry) and correlates with behavioral and emotional problems of children. In addition, parental stress can result in a biased parental perception of child's behavior and emotions. These interrelations were examined in a normal (N = 320) and a clinical (N = 75) sample. The "Eltern-Belastungs-Screening zur Kindeswohlgefährdung" (EBSK; Deegener, Spangler, Körner & Becker, 2009) was used for the assessment of parental stress. As expected, increased EBSK scores were overrepresented in the clinical sample. In both samples stressed parents reported having children with more behavioral and emotional problems. Children of stressed parents in turn reported significantly less problems than their parents did. The rating of independent third persons, e.g. teachers, was not available and should be added in future research. Restrictions in methodology and conclusions for practice are discussed.

  15. Auf dem Weg zur digitalen Fakultät - moderne IT Infrastruktur am Beispiel des Physik-Departments der TU München

    NASA Astrophysics Data System (ADS)

    Homolka, Josef

    Der Geschäftsbetrieb einer Universität ist durch zunehmende Digitalisierung und Nutzung elektronischer Medien gekennzeichnet. Die Einführung immer leistungsfähigerer zentraler IT-Systeme führt zu einer komplexen Vielfalt heterogener Benutzer- und Administrationsschnittstellen. Zur Schaffung einer umfassenden benutzerfreundlichen und nahtlosen IT-Infrastruktur ist die Beteiligung aller organisatorischen Einheiten und Ebenen erforderlich. Am Physik-Departement der Technischen Universität München wurden unter Integration eigener Ressourcen mit zentralen Ressourcen, die im Rahmen des IntegraTUM Projektes entwickelt und bereitgestellt wurden, existierende Dienste weiterentwickelt und neue Angebote aufgebaut. Das System, bestehend aus den Komponenten Netzwerk, Arbeitsplatzrechner, Serverinfrastruktur, E-Mail-Service, WWWDienst, Datenhaltung und Software wurde für die Nutzerkreise Studenten und Mitarbeiter im Hinblick auf Anwenderfreundlichkeit und nahtlosen Zugriff optimiert.

  16. Rapidly evolving and luminous transients from Pan-STARRS1

    SciT

    Drout, M. R.; Chornock, R.; Soderberg, A. M.

    2014-10-10

    In the past decade, several rapidly evolving transients have been discovered whose timescales and luminosities are not easily explained by traditional supernovae (SNe) models. The sample size of these objects has remained small due, at least in part, to the challenges of detecting short timescale transients with traditional survey cadences. Here we present the results from a search within the Pan-STARRS1 Medium Deep Survey (PS1-MDS) for rapidly evolving and luminous transients. We identify 10 new transients with a time above half-maximum (t {sub 1/2}) of less than 12 days and –16.5 > M > –20 mag. This increases the numbermore » of known events in this region of SN phase space by roughly a factor of three. The median redshift of the PS1-MDS sample is z = 0.275 and they all exploded in star-forming galaxies. In general, the transients possess faster rise than decline timescale and blue colors at maximum light (g {sub P1} – r {sub P1} ≲ –0.2). Best-fit blackbodies reveal photospheric temperatures/radii that expand/cool with time and explosion spectra taken near maximum light are dominated by a blue continuum, consistent with a hot, optically thick, ejecta. We find it difficult to reconcile the short timescale, high peak luminosity (L > 10{sup 43} erg s{sup –1}), and lack of UV line blanketing observed in many of these transients with an explosion powered mainly by the radioactive decay of {sup 56}Ni. Rather, we find that many are consistent with either (1) cooling envelope emission from the explosion of a star with a low-mass extended envelope that ejected very little (<0.03 M {sub ☉}) radioactive material, or (2) a shock breakout within a dense, optically thick, wind surrounding the progenitor star. After calculating the detection efficiency for objects with rapid timescales in the PS1-MDS we find a volumetric rate of 4800-8000 events yr{sup –1} Gpc{sup –3} (4%-7% of the core-collapse SN rate at z = 0.2).« less

  17. ATel 7534: Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Pan, Y.-C.; Foley, R. J.; Downing, S.; Jha, S. W.; Rest, A.; Scolnic, D.; Smith, K. W.; Wright, D.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.

    2015-05-01

    We report the following classifications of optical transients from spectroscopic observations with the KOSMOS on the Mayall telescope. Targets were supplied by the Pan-STARRS Survey for Transients (PSST). ...

  18. Induced Electrical Transients Observed in the TALOS-W Adaption Kit

    SciT

    Morgan, G.E.

    1959-09-01

    An undesirable electrical transient signal had been found to appear in the Mk 5 Mod 0 adaption kit at the time of a TALOS-W missile power changeover. A description of the transient, suggested cause, and cure were discussed.

  19. iPTF discovery and identification of bright transients

    NASA Astrophysics Data System (ADS)

    Adams, Scott; Karamehmetoglu, Emir; Roy, Rupak; Neill, James D.; Walters, Richard; Cook, Dave; Kupfer, Thomas; Cannella, Chris; Blagorodnova, Nadejda; Yan, Lin; Kasliwal, Mansi; Kulkarni, Shri

    2017-02-01

    The intermediate Palomar Transient Factory (ATel #4807) reports the discovery of the following bright transients. We report as ATel alerts all objects brighter than 19 mag. Our discoveries are reported in two filters: sdss-g and Mould-I, denoted as g and I. All magnitudes are obtained using difference image photometry based on the PTFIDE pipeline described in Masci et al. 2016.Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R), and RB5 (Wozniak et al. 2013AAS...22143105W).

  20. Transient transfection of mammalian cells using a violet diode laser

    NASA Astrophysics Data System (ADS)

    Torres-Mapa, Maria Leilani; Angus, Liselotte; Ploschner, Martin; Dholakia, Kishan; Gunn-Moore, Frank J.

    2010-07-01

    We demonstrate the first use of the violet diode laser for transient mammalian cell transfection. In contrast to previous studies, which showed the generation of stable cell lines over a few weeks, we develop a methodology to transiently transfect cells with an efficiency of up to ~40%. Chinese hamster ovary (CHO-K1) and human embryonic kidney (HEK293) cells are exposed to a tightly focused 405-nm laser in the presence of plasmid DNA encoding for a mitochondrial targeted red fluorescent protein. We report transfection efficiencies as a function of laser power and exposure time for our system. We also show, for the first time, that a continuous wave laser source can be successfully applied to selective gene silencing experiments using small interfering RNA. This work is a major step towards an inexpensive and portable phototransfection system.