54,521 research outputs found
Magnetic fields in axisymmetric neutron stars
No full textWe derive general equations for axisymmetric Newtonian magnetohydrodynamics and use these as the basis of a code for calculating equilibrium configurations of rotating magnetized neutron stars in a stationary state. We investigate the field configurations that result from our formalism, which include purely poloidal, purely toroidal and mixed fields. For the mixed-field formalism, the toroidal component appears to be bounded at less than 7 per cent. We calculate distortions induced both by magnetic fields and by rotation. From our non-linear work, we are able to look at the realm of validity of perturbative work: we find for our results that perturbative-regime formulae for magnetic distortions agree to within 10 per cent of the non-linear results if the ellipticity is less than 0.15 or the average field strength is less than 10^17 G. We also consider how magnetized equilibrium structures vary for different polytropic indices
Traumatic identity and aura in David Lodge's "Author, author"
No full textEste artículo analiza la novela Author, Author (2004) de David Lodge como ejemplo de bioficción neo-victoriana centrada en una celebridad, en este caso concreto, Henry James. El género forma parte del renacimiento Victoriano actual que afecta a los estudios culturales en su conjunto. Mi argumento central es que la novela de Lodge constituye una respuesta a las ansiedades culturales actuales, en particular a las que se refieren a la crisis identitaria y autoría literaria, así como a la pérdida del aura artística de Walter Benjamin, sublimándolas a través de los traumas de finales del siglo XIX. La elección de James, como demuestra el artículo, no es casual. Es el último representante de un mundo perdido en el que el aura aún tenía un espacio; el ser humano en crisis y traumatizado porque no encaja en un status quo nuevo.This paper delves into David Lodge’s Author, Author (2004) as an example of neo-Victorian celebrity biofiction, more concretely on Henry James. The genre belongs to the wave of Victorian revival in current literature which also affects cultural studies in general. My main contention is that Lodge’s novel responds to current cultural anxieties, particularly the crisis of identity and authorship and the end of Walter Benjamin’s concept of aura, by sublimating them into late-nineteenth-century traumata. The choice of James is, the article argues, not casual. He represents the redeeming figure of a lost auratic world; the human in crisis, traumatized because he does not fit in the new status quo
Identifying author-inventors from Spain: methods and a first insight into results
No full textThe aim of this paper is to describe a matching and disambiguation methodology for the identification of author-inventors located in the same country. It aims to maximize precision and recall rates by taking into account national name writing customs in the name matching stage and by including a recursive validation step in the person disambiguation stage. An application to the identification of Spanish author-inventors is described in detail, where all SCOPUS 2003-2008 publications of Spanish authors are matched to all 1978-2009 EPO applications with Spanish inventors. Using this data, we identify 4,194 Spanish author-inventors. A first look at their patenting and publication patterns reveal that Spanish author-inventors make quite a significant contribution to the overall country’s scientific and technological production in the time periods considered: 27% of all EPO patent applications invented in Spain and 15% of all SCOPUS scientific articles authored in Spain, with important differences across fields and excluding journals in non-technologically relevant fields.Peer reviewe
Lander und Hexabenzocoronen Derivate auf Kupfer Oberflächen
No full textTitle Page
Abstract, Kurzfassung, Contents, Acronyms
1 Introduction 1
2 Basic Principles 5
2.1 The Scanning Tunnelling Microscope 5
2.2 Theoretical Description of the Tunnelling Process 7
2.3 Scanning Tunnelling Spectroscopy 12
2.4 STM induced Manipulation 14
2.5 Elastic Scattering Quantum Chemistry 19
3 Experimental 23
3.1 The UHV Chamber and the LT-STM 23
3.2 The Substrates 27
3.2.1 Cu(111) 27
3.2.2 Cu(211) 28
3.3 The Molecules 30
3.3.1 Lander Type Molecules 30
3.3.2 HBC, HPB, and Derivatives 36
3.4 Sample Preparation 39
4 Lander/Cu(211) - Selective Adsorption and Surface Restructuring 43
4.1 Preparation at Low Sample Temperature 44
4.2 Preparation at High Sample Temperature 49
4.3 Formation of Molecular Chains 57
4.4 Conclusions 58
5 Lander/Cu(111) - Molecule-Metal Contact 61
5.1 Adsorption Geometry 63
5.2 Manipulation 64
5.3 Scattering of Surface State Electrons at Lander Molecules 67
5.4 Contacting Lander Molecules to Step Edges 76
5.5 Conclusions 86
6 Molecular Self-Ordering 89
6.1 Monolayer Structures 90
6.1.1 HPB/Cu(111) 90
6.1.2 HBC/Cu(111) 94
6.1.3 HB-HBC/Cu(111) 96
6.1.4 HB-HPB/Cu(111) 99
6.2 Comparison of Molecular Growth 102
6.3 Conclusions 105
7 Manipulation of HBC derivatives 107
7.1 Manipulation of Isolated Molecules 108
7.2 Manipulation Within Molecular Structures 111
7.3 Manipulation of Atoms with Molecules 117
7.4 Conclusions 121
8 Summary and Outlook 123
References 127
Curriculum Vitae, Publications, Acknowledgements 137In this thesis, large organic molecules, namely derivatives of Lander and
hexa-peri-hexabenzocoronene (HBC), are studied on copper surfaces by means of
low temperature scanning tunnelling microscopy (LT-STM). The adsorption of the
Lander molecules, custom designed molecular wires, is investigated temperature
dependent on Cu(111) and Cu(211). On the stepped Cu(211) surface an adsorbate
induced restructuring for temperatures above 160 K is discussed. Due to the
interplay between STM measurements and theoretical calculations, the
adsorption geometry of single molecules can be determined. Moreover, the STM
induced lateral manipulation of Lander molecules is investigated. For the
first time, an atomically defined contact between a metal electrode and a
molecular wire could be established. To do so Lander molecules are manipulated
to an artificially created step edge of known geometry. Scattering of Cu(111)
surface state electrons is used to probe the interaction of molecules with the
metal electrode. By analysis with multiple scattering model calculations, the
molecular contact to the electrode can be traced back to the molecular end
group. Monolayer structures of four different derivatives of HBC on Cu(111),
formed due to molecular self-organisation, are determined. By comparison of
the different molecular species it is possible to identify the chemical groups
that are responsible for the anchoring to the substrate, the intermolecular
bonding, and the molecular orientation. Molecular STM induced manipulation
within molecular structures showed that the high level of precision, regarding
position and orientation of molecules inside the monolayer structure, is
maintained upon manipulation. Furthermore, it is shown that molecule-adatom
interactions can be used to accumulate atoms under molecules.In dieser Arbeit werden große organische Moleküle, Derivate von Lander und
Hexa-peri-Hexabenzocoronen (HBC), auf Kupferoberflächen mittels Tief-
Temperatur Raster-Tunnel-Mikroskopie (TT-RTM) untersucht. Die Adsorption von
Lander Molekülen, speziell entworfenen molekularen Drähten, wurde
temperaturabhängig auf Cu(111) und Cu(211) untersucht. Auf der gestuften
Cu(211) Oberfläche wird eine Adsorbat-induzierte Oberflächenrestrukturierung
diskutiert. Durch das Zusammenspiel von RTM Messungen und theoretischen
Rechnungen kann die genaue Adsorptionsgeometrie von einzelnen Molekülen
bestimmt werden. Außerdem wird die STM induzierte laterale Manipulation der
Moleküle untersucht. Zum ersten Mal wurde ein atomar definierter Kontakt
zwischen einem molekularen Draht und einer metallischen Elektrode hergestellt.
Dazu wurden Lander Moleküle an eine künstlich erzeugte Stufenkante von
bekannter Geometrie gebracht. Die Streuung von Elektronen in Cu(111)
Oberflächen-Zuständen wird genutzt um die Wechselwirkung zwischen Molekül und
Metall-Elektrode zu untersuchen. Durch eine Analyse mittels Mehrfach-Streuung
Model-Rechnungen kann der Kontakt zur Elektrode auf die molekulare Endgruppe
zurückgeführt werden. Die durch Selbstordnung verschiedener Derivate von HBC
auf Cu(111) ausgebildeten Monolagenstrukturen werden bestimmt. Durch Vergleich
der Derivate können die chemischen Gruppen, die für die Anbindung zum
Substrat, die intermolekulare Bindung und die molekulare Orientierung
verantwortlich sind, identifiziert werden. Es zeigt sich, dass das hohe Maß an
Genauigkeit bezüglich molekularer Position und Ausrichtung in
Monolagenstrukturen auch nach RTM induzierter Manipulation erhalten bleibt.
Ferner wird gezeigt, dass Molekül-Adatom Wechselwirkungen genutzt werden
können um Atome unter Molekülen zu akkumulieren
¿Qué es el plagio?
No full textEl plagio es tomar un fragmento de una obra artística o intelectual ajena y hacerlo pasar como propio, sin la debida acreditación del autor.Plagiarism is taking a fragment of another's artistic or intellectual work and passing it off as one's own, without due accreditation of the author
Microbial larvicide application by a large-scale, community-based program reduces malaria infection prevalence in urban Dar es Salaam, Tanzania.
No full textBACKGROUND\ud
\ud
Malaria control in Africa is most tractable in urban settlements yet most research has focused on rural settings. Elimination of malaria transmission from urban areas may require larval control strategies that complement adult mosquito control using insecticide-treated nets or houses, particularly where vectors feed outdoors.\ud
\ud
METHODS AND FINDINGS\ud
\ud
Microbial larvicide (Bacillus thuringiensis var. israelensis (Bti)) was applied weekly through programmatic, non-randomized community-based, but vertically managed, delivery systems in urban Dar es Salaam, Tanzania. Continuous, randomized cluster sampling of malaria infection prevalence and non-random programmatic surveillance of entomological inoculation rate (EIR) respectively constituted the primary and secondary outcomes surveyed within a population of approximately 612,000 residents in 15 fully urban wards covering 55 km(2). Bti application for one year in 3 of those wards (17 km(2) with 128,000 residents) reduced crude annual transmission estimates (Relative EIR [95% Confidence Interval] = 0.683 [0.491-0.952], P = 0.024) but program effectiveness peaked between July and September (Relative EIR [CI] = 0.354 [0.193 to 0.650], P = 0.001) when 45% (9/20) of directly observed transmission events occurred. Larviciding reduced malaria infection risk among children < or =5 years of age (OR [CI] = 0.284 [0.101 to 0.801], P = 0.017) and provided protection at least as good as personal use of an insecticide treated net (OR [CI] = 0.764 [0.614-0.951], P = 0.016).\ud
\ud
CONCLUSIONS\ud
\ud
In this context, larviciding reduced malaria prevalence and complemented existing protection provided by insecticide-treated nets. Larviciding may represent a useful option for integrated vector management in Africa, particularly in its rapidly growing urban centres
VLBI observations of the Chang’E-3 lunar lander
No full textDiese Dissertation beschäftigt sich mit dem Konzept und der Analyse geodätischer VLBI-Beobachtungen des Chang’E-3-Mondlanders. VLBI ist eine hochpräzise Messtechnik, die in der Geodäsie, Astrometrie und bei Weltraumerkundungen weit verbreitet ist. In den letzten Jahren hat die Beobachtung künstlicher Quellen mit geodätischen VLBI immer mehr an Bedeutung gewonnen. Der aktuelle Stand der Technik befindet sich jedoch erst in der Anfangsphase einer vollständigen Etablierung. Mit der Entwicklung des VLBI Geodetic Observing System (VGOS) wird die Beobachtung künstlicher Quellen mit VLBI ein wichtiger Aspekt zukünftiger geodätischer VLBI-Aktivitäten sein. Folglich sind Forschung und Entwicklung in diesem Bereich in der Gemeinde erwünscht. Das Chang’E-3-Mondlandegerät ist mit einem X-Band-Sender ausgestattet, der die VLBI-Beobachtungen des Mondes von der Erde aus ermöglicht. In einem Projekt namens Öbserving the Chang’E-3 Lunar Lander mit VLBI (OCEL) wurde der Mondlander mit globalen VLBI-Radioteleskopen des Internationalen VLBI-Dienstes für Geodäsie und Astrometrie (IVS) beobachtet. Es ö nete sich eine neue Möglichkeit für die Anwendung der geodätischen VLBI mittels künstlicher Funkquellen. Die Hauptaufgabe der OCEL-Studie besteht aus zwei Teilen: der Bestimmung der Gruppenlaufzeitverzögerungen der Mondlander-Beobachtungen und der Positionsschätzung des Mondlanders. Ausgehend vom geodätischen VLBI-Verarbeitungsworkflow mit der Ermittlung der Gruppenlaufzeitverzögerungen wurden Untersuchungen durchgeführt, um DOR-Töne (Differential One-Way Ranging) mit einem verbesserten Randanpassungsschema zu verarbeiten. Mit diesen Untersuchungen wurde eine vollständige Kette der Verarbeitung der VLBI-Daten für die OCEL-Sessionen mit geeigneten Methoden neu entwickelt. Die Leistung wird durch eine Dreieckschlussanalyse der Laufzeitdifferenzen als Hauptkriterium bewertet. Somit können Gruppenlaufzeitverzögerungen von VLBI-Beobachtungen von DOR-Tönen routinemäßig erhalten werden, was die erste Hauptkomponente dieser Dissertation ist. Der zweite Teil ist die Schätzung der Position des Mondlanders mit diesen Gruppenverzögerungen. Neu ist, dass ein Nahfeldmodell für VLBI-Beobachtungsverzögerungen des Mondlanders entwickelt und die entsprechenden partiellen Ableitungen abgeleitet und implementiert wurden. Ein Vergleich mit dem aktuellsten Nahfeldmodell liefert für unser Modell für den Mondlander eine Übereinstimmung im Pikosekundenbereich. Die mit einer Bedingungsgleichung für die Radialkomponente geschätzte Position unterscheidet sich um etwa 10 Meter von den durch die LRO-Mission (Photogrammetric Lunar Reconnaissance Orbiter) ermittelten Werten. Die Ergebnisse der aktuellen Studie hinsichtlich der erreichten Genauigkeit sind mit denen anderer neuerer Ergebnisse in Bezug auf die Position des Chang’E-3-Mondlanders mit VLBI vergleichbar. Darüber hinaus zeigen die OCEL-Ergebnisse aufgrund des Beitrags des weltweit verteilten IVS-Netzwerks bzw. der Kalibrierungen in Bezug auf die langen Beobachtungsbögen eine bessere Stabilität verglichen mit kurzzeitigen VLBI-Beobachtungen eines Netzwerks einiger regionaler Stationen, die noch mit Entfernungsmessungen und Messungen der Entfernungsrate aus Dopplermessungen ergänzt wurden. Im Jahr 2018 wurde für einige Stunden ein zweiter Senderer am Lander eingeschaltet und der Mondlander erneut mit dem chinesischen Weltraumnetz im VLBI-Modus im sog. Same-Beam-Modus beobachtet. In einer vorläufigen untersuchung haben wir eine Reihe dieser VLBI-Beobachtungen an der Jiamusi-Kashi-Basislinie, mit dem Ziel verwendet, die relative Position der beiden Antennen auf dem Mondlander zu schätzen. Als Observable wurden differentielle Phasenverzögerungen verwendet. Das geometrische Verzögerungsmodell und die entsprechenden partiellen Ableitungen wurden abgeleitet und unter Verwendung des für OCEL entwickelten Nahfeldmodells angewendet. Die geschätzte relative Vektor der Position unterscheidet sich von der a priori-Entfernung um 0.02 zu 0.04 m. Die erreichte Genauigkeit ist mit der relativen Position zwischen dem Mondlander und dem Rover kompatibel. Die Erfahrungen und Ergebnisse der VLBI-Beobachtungen des OCEL-Projekts und der VLBI-Sessionen im Same-Beam-Modus zeigen das Potenzial der VLBI für die Beobachtung künstlicher Ziele. In der Zwischenzeit wurden die hier entwickelten Tools bereits in einer weiteren Mondpositionsbestimmung für die Mondbewegungsüberwachung und für die Mondreferenzrahmenrealisierung mit VLBI eingesetzt.This thesis deals with the concept and the analysis of geodetic VLBI observations of the Chang’E-3 lunar lander. VLBI as a high accuracy measuring technique, is widely used in geodesy, astrometry and deep space explorations. In recent years, tracking artificial sources with geodetic VLBI has gained more and more importance. However, the actual state of the art is only at the starting stage of a full establishment. With the development of the VLBI Geodetic Observing System (VGOS), tracking artificial sources with VLBI will be an important aspect of future geodetic VLBI activities. Consequently, research and development in this area are desired in the community. The Chang’E-3 lunar lander is equipped with an X-band transmitter enabling VLBI observations of the Moon from Earth. In a project called Observing the Chang’E-3 Lunar Lander with VLBI (OCEL), the lunar lander was observed with global VLBI radio telescopes of the International VLBI Service for Geodesy and Astrometry (IVS). It opened a new window for applying geodetic VLBI to artificial radio sources. The main task of the OCEL study is separated in two parts, the determination of the group delays of the lunar lander observations and the position estimation of the lunar lander. Starting the geodetic VLBI processing workflow with the determination of the group delays, investigations have been carried out to process Differential One-way Ranging (DOR) tones with an improved fringe fitting scheme. With these investigations, a complete chain of processing of the VLBI data for the OCEL sessions with proper methods were newly developed. The performance is assessed by triangle closure delay analysis as a main criterion. Thus, group delays of VLBI observations of DOR tones can now be obtained routinely which is the first achievement of this thesis. The second part is the estimation of the position of the lunar lander with these group delays. New is that a near-field model was designed for VLBI delays of observations of the lunar lander and that the corresponding partial derivatives were derived and implemented. Compared with the most up-to-date near field model, the performance of our model is consistent at the picosecond level for the lunar lander. The position estimated with a constraint of the radial component is about 10 meters different from the values determined by the photogrammetric Lunar Reconnaissance Orbiter (LRO) mission. The results of the current study in terms of achieved accuracy are compatible with those of other recent results related the position of the Chang’E-3 lunar lander with VLBI. Besides that, due to the contribution coming from the globally distributed IVS network, respectively the long observing arc and delay referencing calibrations, the OCEL results show a better performance in terms of uncertainties compared to short-duration VLBI and VLBI plus range and range rate from Doppler measurements with a network of a few regional stations. In 2018, a second beacon on the lander was switched on for a few hours and the lunar lander was observed again with the Chinese deep space network in same-beam VLBI mode. In a preliminary investigation, we used a number of these VLBI observations on the Jiamusi-Kashi baseline to estimate the relative position of the two antennas on the lunar lander. Differential phase delays were used as observables. The geometric delay model and the corresponding partial derivatives were derived and applied using the near field model developed for OCEL. The estimated relative position vector di ers from the a priori vector by about 0.02 to 0.04 m. In addition, the relative angles (polar angle and azimuth angle) in a Moon-fixed system PA between the two antennas on the Chang’E-3 lunar lander are estimated. The accuracy achieved is compatible with the relative positioning between the lunar lander and the rover. The experiences gained and results obtained from VLBI observations of the OCEL project and of the same-beam VLBI session reveal the potential of VLBI for observing artificial targets. In the meantime, the tools developed here were already applied in further lunar target positioning, lunar motion monitoring and lunar reference frame realization with VLBI
Experiencing the armed struggle : the Soweto generation and after
No full textIncludes bibliographical references (p. 354-369).This study explores the experiences of the rank-and-file soldiers of Umkhonto we Sizwe and the Azanian People's Liberation Anny. Extensive interviews by the author and other researchers reveal the voices of the soldiers themselves. The African National Congress and Pan African Congress archives at the University of the Western Cape and the University of Fort Hare supplement and verify these oral testimonies, as do some published sources. Most previously published materials about the armed struggle against apartheid have already focused on diplomacy, strategy and tactics, operations, leadership, and human rights abuses to the neglect of the soldiers' actual experiences. This study complements these with significant new oral history materials from the Soweto generation of soldiers and their successors. When dealing with MK, many authors have documented issues of the camp structure in Angola, and operations inside South Africa, so much of this detail is only addressed briefly, leaving space to explore the soldiers' experiences. In the case of APLA, very little has been written on its history, and more detail is provided on these subjects. This study therefore deals with the soldiers' politicisation and motivation for joining the armed struggle, their experiences in leaving South Africa and training in exile, the crises in exile which limited their effectiveness for a time, their return to fight in South Africa, and their difficulties in the "new" South Africa. These materials reveal that vast problems remain facing these veterans of the struggle against apartheid, and that they have the potential, if properly supported and employed, to contribute substantially to the development of present day South Africa. Conversely, if their neglect continues, they also have the potential to bring vast harm to the country. Further use of the investigative tools of oral history, especially if extended to the former soldiers' vernacular languages, is necessary to augment the history of South Africa, and these soldiers' contributions
Evidence for crustal seismic anisotropy at the InSight lander site
No full textWe analyzed broadband and low-frequency events recorded on Mars and made the first detection of horizontally polarized shear wave reflections, which help constrain the crustal structure at NASA's InSight lander site. Coherent signals from five well-recorded marsquakes appear to be independent of the focal depth and are consistent with SH-wave reflections off the topmost crustal interface (8 ± 2 km). This phase confirms the existence of the ∼8 km interface in the crust and the large wave speed (or impedance) contrast across it. The range of acceptable parameters determined from the detected SH-wave reflections differs from the majority of the vertically polarized shear wave models resulting from a previous receiver function study, indicating that the velocity of the vertically polarized waves is larger than that of horizontally polarized waves. We propose that this inconsistency results from the presence of seismic anisotropy within the top crustal layer at the lander site. Modeling results show that dry- or liquid-filled cracks/fractures and igneous intrusions can reproduce the observed radial anisotropy
İcāzet-nāme; اجازتنامه
No full text1. Kitabın İçindekiler : Eserin ilk sayfaları eksiktir. 1a-34b: Hz. Muhammed’in doğumu, ahlakı, mucizeleri, miracı, hicreti, ve ayrıntılı olarak ölümü manzum olarak anlatılır. 35a-36a: Hatim duası; 36b-38a: Münacat duası. 2. Kitabın İçindekiler : İlmiye icazetnamesidir. En sonda Ahmed Nazif Sinobi, belgenin hocası Es-seyyid el-Hâc Rif’at b. el-Hâc İbrahim el-Ankaravi’den aldığı icazet sureti olduğunu belirtir. (46a). Burada Ahmed Nazif Es-Sinobi’nin mührü de vardır. 46a’da son bulan icazetnamenin rıka yazıyla farklı bir kağıda yazılmış bir diğer kopyası da 48b-50b arasındadır. 53b-55a: Farklı bir kağıda farklı bir yazıyla muhtemelen bir mevlidden alınmış Hz. Muhammed’in hayatına ait kısa bir manzume.Original scanned with Zeutschel OS 12000C A2 scanner and saved as 300 ppi uncompressed tiffs. Display images generated in CONTENTdm as JP20002 vol. in 1; 22x16,5 c
- …
