cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Zur Deutung und Bedeutung von Paläoböden im (süddeutschen) Löß
Creators: name: Bleich, Klaus Eberhard
Publisher: name: Geozon Science Media
Year: 1998

description: Voraussetzung für Altersabschätzung und palökologische Einstufung der Paläoböden im Löß ist die Kenntnis von Relief- und Landschaftsposition. An Beispielen aus Süddeutschland wird dargestellt, daß bereits dadurch Eigenschaften (wie Hydromorphie oder veränderte Mächtigkeiten und Humusgehalte) erklärbar sind, die in Unkenntnis der Situation auch als Kriterien für Art und Dauer von Klimaphasen herhalten mußten. Für den Vergleich von Löß/Boden-Abfolgen ist die quantitative Ermittlung von Intensität und Ausmaß der Bodenentwicklung an geeigneten Paläoböden und rezenten Vergleichsböden zweckmäßig. Daraus resultiert eine Beschränkung auf vollständig erhaltene Böden in ebener Lage, jedoch nicht die Vorstellung von einer monotypischen Ausstattung der Paläobodenlandschaften. Auch diese Boden sind durch kaltzeitliche Überprägung verändert. Die unterschiedliche Bedeutung der Bodenhorizonte für die Rekonstruktion der Klimaentwicklung wird abschließend herausgestellt.
description: research
title: System architecture metrics: an evaluation
Creators: name: Shepperd, Martin John
Publisher: name: The Open University
Year: 1991

description: The research described in this dissertation is a study of the application of measurement, or metrics for software engineering. This is not in itself a new idea; the concept of measuring software was first mooted close on twenty years ago. However, examination of what is a considerable body of metrics work, reveals that incorporating measurement into software engineering is rather less straightforward than one might pre-suppose and despite the advancing years, there is still a lack of maturity. The thesis commences with a dissection of three of the most popular metrics, namely Haistead's software science, McCabe's cyclomatic complexity and Henry and Kafura's information flow - all of which might be regarded as having achieved classic status. Despite their popularity these metrics are all flawed in at least three respects. First and foremost, in each case it is unclear exactly what is being measured: instead there being a preponderance of such metaphysical terms as complexIty and qualIty. Second, each metric is theoretically doubtful in that it exhibits anomalous behaviour. Third, much of the claimed empirical support for each metric is spurious arising from poor experimental design, and inappropriate statistical analysis. It is argued that these problems are not misfortune but the inevitable consequence of the ad hoc and unstructured approach of much metrics research: in particular the scant regard paid to the role of underlying models. This research seeks to address these problems by proposing a systematic method for the development and evaluation of software metrics. The method is a goal directed, combination of formal modelling techniques, and empirical ealiat%or. The met\io s applied to the problem of developing metrics to evaluate software designs - from the perspective of a software engineer wishing to minimise implementation difficulties, faults and future maintenance problems. It highlights a number of weaknesses within the original model. These are tackled in a second, more sophisticated model which is multidimensional, that is it combines, in this case, two metrics. Both the theoretical and empirical analysis show this model to have utility in its ability to identify hardto- implement and unreliable aspects of software designs. It is concluded that this method goes some way towards the problem of introducing a little more rigour into the development, evaluation and evolution of metrics for the software engineer.
Linking the chiral and deconfinement phase transitions
Creators: name: Hatta, Yoshitaka
name: Fukushima, Kenji
Publisher: name: arXiv
Year: 2003
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We show that the electric glueball becomes critical at the end-point of the deconfinement phase transition in finite temperature QCD. Based on this observation and existing lattice data, we argue that the chiral phase transition at a zero quark mass and the deconfinement phase transition at an infinite quark mass are continuously connected by the glueball-sigma mixing.
description: 4 pages, terminology corrected. To appear in Phys. Rev. D
title: Bulk Properties and Evolution of Jupiter-Family Comet Nuclei
Creators: name: Kokotanekova, Rosita
Publisher: name: The Open University
Year: 2018

description: This thesis presents the results from photometric time-series observations of Jupiter-family comets (JFCs). A method was developed that allows mutual absolute photometric calibration of data taken at different epochs with different instruments and results in absolute-calibration uncertainty of ∼0.02 mag. The method was applied to various datasets with the goal of studying the rotation rates and surface properties of ten comets.

Previously published properties of JFCs were collected and complemented by new results. The resulting comprehensive sample was used to study the ensemble properties of JFC nuclei. It confirmed the cut-off in bulk density at ∼0.6 g cm−3 and provided evidence for a lower limit on the bulk tensile strength of 10-25 Pa.

New lightcurves of three JFCs were used to look for spin changes over their last orbits. None of the observed comets had detectable period changes, and strict conservative upper limits were set. Comparing these results with all eight other JFCs with measured rotational changes suggests that large JFCs are less likely to undergo rotationally-driven mass-loss, and are therefore more likely to survive more perihelion passages than smaller nuclei. This conclusion is supported by evidence from the cumulative size distributions of JFCs and dormant comets, as well as from recent dynamical simulations.

This work almost doubled the sample of JFCs with both albedos and phase-function slopes known. The extended sample shows a possible correlation of increasing phase-function slopes for larger geometric albedos, which can be interpreted as an evolutionary trend for JFCs. According to this hypothesis, newly activated JFCs have higher albedos and steeper phase functions, which gradually decrease due to sublimation-driven erosion. If confirmed, this correlation could be used to analyse surface erosion from the ground and to distinguish between dormant comets and asteroids.
title: Differentiating noise and modulators in artificial neural networks
Creators: name: Docking, Philip John
Publisher: name: The Open University
Year: 1993

description: Research in Computational Neural Networks is currently taking place at many different levels; from coarse-grain symbolic models to fine-grain representations of neurons and cell processes. One feature that the different approaches share, is that they are all in relative infancy. Thus, most research concentrates on gross aspects of neural communication and methods of computational simulation. Recently, some clues have been found which point to more subtle mechanisms underlying the information processing capability of neural 'nodes'. These clues are the improvement in network operation by the injection of random noise; and the neurobiological finding that neuropeptides may exist as slower Signal transmission channels between neurons. This study concerns the difference between random noise injection, and directed, low-level, activity injections which are postulated to be produced by neuromodulators such as neuropeptides. The findings of this study are that random noise does, indeed, enhance the operation of coarse-grain neural models; and that a 'neuropeptidergic' analogue also enhances operation; but to a different extent, and probably through a different mechanism. Further testing of a medium-grain computer model gives some indication of how a neuropeptidergic modulation might affect real neurons, by extending the time-course of the activation of the neuron. This appears to be a similar mechanism to that postulated for the coarse-grain 'neuropeptidergic' simulation model. Given these findings, is it possible that signal transmission in real nervous systems assume these mechanisms? If so, it may be possible that a process of concurrent propagation, through different signal channels, also occurs in real nervous systems, making the nervous system much more complex than current models allow.
title: The impact of the Great War on a local community: the case of East Lothian
Creators: name: Cranstoun, James G. M.
Publisher: name: The Open University
Year: 1993

description: This is a study of the impact of the Great War on one local community - the Lowland Scottish county of East Lothian. The thesis examines the economic, social and political consequences of the war in the short term of the war years and in the longer perspective of the first pre-war decade. The precise impact of the military presence in the county during the war and the extending role of government during the war are also discussed. Chapter 1 surveys the literature on the effects of the Great War as relevant to this study. Chapters 2 and 3 provide a pre-war background to the geography, economy and demography of the county and examine its society and politics. Chapter 4 outlines the military aspects in a local context, including the voluntary and compulsory phases of recruiting, mobilisation by local military units and the impact of the military presence. Chapter 5 studies the impact of the war on the three major industries of the county - farming, coal mining and fishing - how their activities were disrupted by the war and to what extent these difficulties were surmounted. Chapter 6 examines the consequences of the war for East Lothian society, its demographic effect, the impact on education and crime and religion. The voluntary activities to aid the war effort are described. Chapter 7 traces the political life of the county during the war culminating in the 1918 General Election and considers the changing role of government during the war. Chapter 8 and 9 examine in turn economic, social and political trends in the county during the post-war decade. The study found that, generally, local trends fitted in with national developments. The problems of the coal industry in the 1920's can be clearly related to the disruptive effect of the Great War, while those of agriculture and fishing illustrate the effect of more long term trends. There were limited social gains in the form of housing and increased educational provision as a result of legislation at the end of the war. The disintegration of Liberalism as a political force in East Lothian was to a great extent attributable to the failures and divisions of Liberals, though increasing working-class consciousness was also a factor in the growth of support for Labour.
A new formulation of compartmental epidemic modelling for arbitrary distributions of incubation and removal times
Creators: name: Hernández, P.
name: Pena, C.
name: Ramos, A.
name: Gómez-Cadenas, J. J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: FOS: Biological sciences

description: The paradigm for compartment models in epidemiology assumes exponentially distributed incubation and removal times, which is not realistic in actual populations. Commonly used variations with multiple exponentially distributed variables are more flexible, yet do not allow for arbitrary distributions. We present a new formulation, focussing on the SEIR concept that allows to include general distributions of incubation and removal times. We compare the solution to two types of agent-based model simulations, a spatially homogeneous one where infection occurs by proximity, and a model on a scale-free network with varying clustering properties, where the infection between any two agents occurs via their link if it exists. We find good agreement in both cases. Furthermore a family of asymptotic solutions of the equations is found in terms of a logistic curve, which after a non-universal time shift, fits extremely well all the microdynamical simulations. The formulation allows for a simple numerical approach; software in Julia and Python is provided.
description: 21 pages, 11 figures. v2 matches published version: improved presentation (including title, abstract and references), results and conclusions unchanged
Schwermineralverteilung und Alter pleistozäner mariner Sedimente in Mittelitalien
Creators: name: Radtke, Ulrich
name: Tillmanns, Wolfgang
Publisher: name: Geozon Science Media
Year: 1984

description: In den südlichen Maremmen zwischen Civitavecchia und dem Monte Argentario gelang es, mittels der Schwermineralanalyse pleistozäne marine Sedimente unterschiedlichen Alters voneinander abzugrenzen. Anhand der Beschreibung einiger Profile wird gezeigt, daß die ältesten pleistozänen marinen Terrassensedimente durch ein völliges Fehlen vulkanischer Schwerminerale gekennzeichnet sind, d. h. ihre Ablagerung geschah vor 700 000—600 000 BP, dem Beginn des vulsinischen Vulkanismus. Sedimente des oberen Mittelpleistozäns und des Jungpleistozäns zeigen ab ca.430 000 BP, dem Beginn der Hauptaktivität des Vulkanismus, ein sehr einheitliches Schwermineralspektrum, welches durch die Dominanz des Augits (90—100%) gekennzeichnet ist. Sedimente, die zwischen Beginn des Vulkanismus und seiner Hauptaktivität abgelagert wurden (700 000—600 000 bis 430 000 BP), besitzen ein Schwermineralspektrum, welches sich durchschnittlich nur zur Hälfte aus vulkanischen Schwermineralen zusammensetzt.
description: research
title: Spherical wave reflection and transmission
Creators: name: Chen, Yu
Publisher: name: The Open University
Year: 1992

description: This study is concerned with the reflection and transmission of spherical waves at a plane interface between two different media. The phenomenon of the reflection and transmission of spherical waves has been studied by means of analytical methods, numerical computation, and experimental tests. A new integral representation for a spherical wave is obtained by transforming Lamb/Sommerfeld's integral representation. The new integral has no singularity so it allows more accurate numerical integration. A new proof of Lamb/Sommerfeld's integral representation for a spherical wave is presented based on the new integral. By using the new form of solutions for reflected waves and existing solutions for transmitted waves, numerical studies have been carried out to examine. the phenomenon of reflection and transmission. of spherical waves at plane surfaces of discontinuity in material properties. It is shown that the effective critical angle for the total reflection of a spherical wave is greater than that of a plane wave at a hard boundary, and that when the source height increases the effective critical angle for the total reflection of a spherical wave tends to that of a plane wave. It is shown that recent predictions of spherical wave reflection and transmission coefficients greater than 1 at normal incidence under certain condition are probably due to numerical integration error. It also has been found that for spherical wave reflection and transmission, the time average energy flux, normal to a plane parallel to the plane of discontinuity, may locally be in the direction opposite to that of the direction of energy transmission over the plane as a whole. This so-called "backward wave" occurs in an interference between the direct and reflected waves, as well as in a transmitted wave. An indirect test on the theory has been performed to check the pressure field, above a rigid boundary, predicted by the spherical wave theory. Theoretical and experimental results were in good agreement.
Partition function zeros at first-order phase transitions: A general analysis
Creators: name: Biskup, Marek
name: Borgs, Christian
name: Chayes, Jennifer T.
name: Kleinwaks, Logan J.
name: Kotecky, Roman
Publisher: name: arXiv
Year: 2003
Subjects: subject: Mathematical Physics (math-ph)
subject: Complex Variables (math.CV)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 82B05; 82B26; 26C10; 82B20

description: We present a general, rigorous theory of partition function zeros for lattice spin models depending on one complex parameter. First, we formulate a set of natural assumptions which are verified for a large class of spin models in a companion paper [BBCKK2, math-ph/0304007]. Under these assumptions, we derive equations whose solutions give the location of the zeros of the partition function with periodic boundary conditions, up to an error which we prove is (generically) exponentially small in the linear size of the system. For asymptotically large systems, the zeros concentrate on phase boundaries which are simple curves ending in multiple points. For models with an Ising-like plus-minus symmetry, we also establish a local version of the Lee-Yang Circle Theorem. This result allows us to control situations when in one region of the complex plane the zeros lie precisely on the unit circle, while in the complement of this region the zeros concentrate on less symmetric curves.
description: 52 pages, 3 eps figs, to appear in Commun. Math. Phys.; see also math-ph/0304007 and math-ph/0004003
Sharing the Lane : Bicycling through Barriers East of the Anacostia River
Creators: name: Keutel, Malina
Publisher: name: American University (Washington, D.C.)
Year: 2023
Subjects: classificationCode: 3509
subject: Transportation, logistics and supply chains
classificationCode: 4403
subject: Demography
subject: FOS: Sociology

description: Description to be added
The Detector and Interaction Region for a Photon Collider at TESLA
Creators: name: Rosca, Aura
Publisher: name: arXiv
Year: 2003
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: TESLA is designed as an electron-positron linear collider (LC) based on super-conducting technology. A second interaction region is forseen to be incorporated in the design allowing its possible operation as a photon collider. In this paper I describe the basic design of the $γγ$ interaction region taking into account the beam-beam and laser related issuses and review some aspects of other accelerator components such as the feedback system and the beam dump which are critical to the operation of TESLA as a photon collider.
description: Talk presented at HEP03 conference, Aachen, July 2003, 3 pages, 4 figures
title: The making of biotechnology: a case study of radical innovation
Creators: name: Chataway, Joanna Caroline
Publisher: name: The Open University
Year: 1992

description: This study examines decision making in large and small firms undertaking biotechnology innovation and identifies factors influencing innovation. It also considers aspects of environments external to firms, but relevant to the process of innovation. The study suggests that innovation is best understood as process of change both within the firm and in the external environment. Factors internal to firms influencing key decisions included economic and political evaluations, company culture, organization, and in large firms, previous areas of corporate activity. A scarcity of appropriate knowledge relating to technical and non-technical aspects of innovation acted as severe restraints to Dedicated Biotechnology Firms (DBFs). Factors external to firms shaping decisions about the technology included changes in the socio-economic and political environment, risk regulation and patenting. Lack of funding and difficulties associated with venture capital constituted additional hurdles for DBFs. The findings of the study highlight a series of erroneous assumptions built into the linear model of innovation. The cumulative nature of innovation and the importance of 'learning by doing' constitute elements of the critique of the linear model. For related reasons, some Post Fordist theories of current change in advanced industrialized countries, particularly those which advocate flexible specialization as a new model for industrial growth also prove problematic.
Quartärmorphologische Untersuchungen an den Küsten der M. Poro—Halbinsel, Westkalabrien (Beiträge zur regionalen Küstenmorphologie des Mittelmeerraumes III)
Creators: name: Kelletat, Dieter
Publisher: name: Geozon Science Media
Year: 1973

description: Die M. Poro-Halbinsel zwischen den Golfen von S. Eufemia und Gioia besteht zum großen Teil aus Granit. Eine Pliozänmulde trennt die zentrale 600 m hohe Rumpffläche vom Hinterland. An der W- und N-Abdachung lagern dem Granit miozäne Sande, überwiegend verfestigt, an. Die SW-Küste zwischen Nicotera und Capo Vaticano ist ein denudativ und marin überprägter altquartärer Bruch. Der exponierte NW-Teil wird gekennzeichnet von bis 100 m hohen Granitkliffen mit vorgelagerten Klippen und flach verfüllten Abrasionsbuchten. In der Küstenlandschaft des Westens und Nordens liegen 3 bis 5 hoch hinausgehobene insgesamt pleistozäne, aber bisher nicht näher datierte Abrasionsterrassen. In den beiden flankierenden Ebenen sind 2 altquartäre Transgressionszyklen (Calabrien unter NN, Sicilien bis + 150 m) nachgewiesen. Ein kleines Tyrrhenvorkommen ist bei Vibo Valentia in 35—40 m ü. M. bekannt, doch fehlen hier Terrassen. In der Nähe des Capo Vaticano wurde auf einer unteren bis 105 m ansteigenden Abrasionsterrasse in 70 m ü.M. eine fossilreiche Strandablagerung (wahrscheinlich Tyrrhen I) gefunden. Tiefer liegt noch eine präflandrische Abrasionsleiste bei 5—6 m ü.M. Drei flandrische Formungsphasen sind um die ganze Halbinsel und an den benachbarten Golfen gleichartig ausgebildet: auf kräftige Kliffbildung folgte eine Verfüllung von Abrasionsbuchten und Glättung der Küstenkontur. Der jüngste noch andauernde Vorgang ist eine Aufzehrung dieser holozänen Terrassen. Der Höchststand der flandrischen Transgression lag in diesem Gebiet nicht wesentlich über dem heutigen Meeresniveau. Ein nach Osten gerichteter Materialversatz hat im 19. und 20. Jahrh. im Nordteil des M. Poro zu Strandverbreiterung und Versandung von Häfen geführt. Den gegenwärtigen dynamischen Zustand der Halbinselküsten verdeutlichen folgende Zahlen: an 37% der Küstenstrecke herrscht Abrasion am Festgestein. 63% bestehen aus Lockermaterial. Davon werden 58% gegenwärtig abradiert. Etwa 17% sind wahrscheinlich stabil, ca. 25% werden akkumulativ verbreitert. Dieser letzte Zustand ist fast ausschließlich auf den Nordosten beschränkt, wo von zwei Seiten durch Verdriftung Material zusammengeführt wird.
description: research
SynthETIC: an individual insurance claim simulator with feature control
Creators: name: Avanzi, Benjamin
name: Taylor, Gregory Clive
name: Wang, Melantha
name: Wong, Bernard
Publisher: name: arXiv
Year: 2020
Subjects: subject: Risk Management (q-fin.RM)
subject: Applications (stat.AP)
subject: FOS: Economics and business
subject: FOS: Computer and information sciences
subject: 91G70, 91G60, 62P05

description: Recent years have seen rapid increase in the application of machine learning to insurance loss reserving. They yield most value when applied to large data sets, such as individual claims, or large claim triangles. In short, they are likely to be useful in the analysis of any data set whose volume is sufficient to obscure a naked-eye view of its features. Unfortunately, such large data sets are in short supply in the actuarial literature. Accordingly, one needs to turn to synthetic data. Although the ultimate objective of these methods is application to real data, the use of synthetic data containing features commonly observed in real data is also to be encouraged. While there are a number of claims simulators in existence, each valuable within its own context, the inclusion of a number of desirable (but complicated) data features requires further development. Accordingly, in this paper we review those desirable features, and propose a new simulator of individual claim experience called `SynthETIC`. Our simulator is publicly available, open source, and fills a gap in the non-life actuarial toolkit. The simulator specifically allows for desirable (but optionally complicated) data features typically occurring in practice, such as variations in rates of settlements and development patterns; as with superimposed inflation, and various discontinuities, and also enables various dependencies between variables. The user has full control of the mechanics of the evolution of an individual claim. As a result, the complexity of the data set generated (meaning the level of difficulty of analysis) may be dialled anywhere from extremely simple to extremely complex.
Deep Learning for estimating parameters of Gravitational Waves
Creators: name: Singh, Shashwat
name: Singh, Amitesh
name: Prajapati, Ankul
name: Pathak, Kamlesh N
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In recent years, improvements in Deep Learning (DL) techniques towards Gravitational Wave (GW) astronomy have led to a significant rise in the development of various classification algorithms that have been successfully employed to extract GWs of binary blackhole merger events from noisy time-series data. However, the success of these models is constrained by the length of time-sample and the class of GW source: binary blackhole and neutron star binaries to some extent. In this work, we intended to advance the boundaries of DL techniques using Convolutional Neural Networks, to go beyond binary classification and predict the physical parameters of the events. We aim to propose an alternative method that can be employed for realtime detection and parameter prediction. The DL model we present has been trained on 12s of data to predict the GW source parameters if detected. During training, the maximum accuracy attained was 90.93%, with a validation accuracy of 89.97%.
description: 15 pages
title: Work-based subjectivity and identity: assisted self-service in contemporary British retailing
Creators: name: Du Gay, Paul
Publisher: name: The Open University
Year: 1992

description: This thesis explores the discursive construction of work-based subjectivity and identity. It seeks to analyse both theoretically and empirically how people are 'made up' at work, first, by creating a theoretical framework for exploring the discursive production of work-based subjectivities and identities and second, by deploying this framework to examine the production of new work identifies and the construction of particular work-based subjects in a specific service industry. The organization of the thesis reflects this two-fold division. Part one (chapters two, three and four) explores certain limitations in traditional approaches to the analysis of work identity within sociology and attempts to construct a tentative alternative framework for analysing the discursive construction of workbased subjectivity and identity. The concept of 'discourse', it is argued, provides a means of overcoming the 'binary oppositions' - between 'individual' and 'productive apparatus' and 'ideology' and 'truth' - that have characterised analyses of work-identity within sociology by indicating the relational and dislocated nature of any social identity. In the second part of the thesis (chapters five, six and seven), the theoretical framework developed in part one is deployed to examine the construction of new work identities and the production of particular work-based subjects in contemporary British retailing. Thus, in part two of the thesis, the retailing sector functions as a 'case study' for exploring how people are 'made up' at work in the present.
title: Breastfeeding and the social control of women
Creators: name: Dyball, Celia
Publisher: name: The Open University
Year: 1993

description: Breastfeeding remains problematic in our society despite its being a 'natural' physiological process, its official encouragement as the healthiest way to feed babies and its revival in popularity amongst mothers over the last thirty years. Many mothers give up early and turn to bottle-feeding, and a substantial minority choose not to breastfeed at all. The aim of this research was to study mothers' feeding experiences in the context of the culture and organisation of western industrialised society. The small sample from a single area, whilst not claiming to be rigorously representative, was drawn nevertheless from a community which was very much the product of western industrialised society. Three in-depth interviews were conducted with 47 mothers having their first babies. The first interview was less than a month before the birth, the second about a month after, and the third at about five months. Most wanted to breastfeed, but found it a struggle against doubts and difficulties stemming from lack of knowledge, conflicting ideas and cultural embarrassment. Even those who continued breastfeeding were dependent on bottle-feeding to overcome problems. Health education on the benefits of breastfeeding and coherent advice based on 'demand feeding' will not solve problems stemming from cultural embarrassment and incompatibility with other culturally defined duties and social activities, but setting an unattainable 'natural ideal' could contribute to women's feelings of guilt or failure when they compromise with bottle-feeding, or choose not to breastfeed at all.
Analysis of the Mobility-Limiting Mechanisms of the Two-Dimensional Hole Gas on Hydrogen-Terminated Diamond
Creators: name: Peterson, Ricardo
name: Malakoutian, Mohamadali
name: Xu, Xiaoqing
name: Chapin, Caitlin
name: Chowdhury, Srabanti
name: Senesky, Debbie G.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applied Physics (physics.app-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Here we present an analysis of the mobility-limiting mechanisms of a two-dimensional hole gas on hydrogen-terminated diamond surfaces. The scattering rates of surface impurities, surface roughness, non-polar optical phonons, and acoustic phonons are included. Using a Schrodinger/Poisson solver, the heavy hole, light hole, and split-off bands are treated separately. To compare the calculations with experimental data, Hall-effect structures were fabricated and measured at temperatures ranging from 25 to 700 K, with hole sheet densities ranging from 2 to 6$\times10^{12}\;\text{cm}^{-2}$ and typical mobilities measured from 60 to 100 cm$^{2}$/(V$\cdot$s) at room temperature. Existing data from literature was also used, which spans sheet densities above 1$\times10^{13}\;\text{cm}^{-2}$. Our analysis indicates that for low sheet densities, surface impurity scattering by charged acceptors and surface roughness are not sufficient to account for the low mobility. Moreover, the experimental data suggests that long-range potential fluctuations exist at the diamond surface, and are particularly enhanced at lower sheet densities. Thus, we propose a second type of surface impurity scattering which is caused by disorder related to the C-H dipoles.
description: 11 pages, 7 figures
title: Platinum-group elements in the ultrabasic rocks of the Braganca and Morais massifs, northern Portugal
Creators: name: Bridges, John Charles
Publisher: name: The Open University
Year: 1992

description: The ultrabasic rocks studied in this thesis are located in the Upper Allochthonous Thrust Complex nappes of the Braganca and Morais massifs, Träs-os-Montes, N. Portugal. They are relicts of residual mantle and cumulates formed at a destructive continental margin. In the Braganca massif, the ultrabasic rocks consist mainly of a harzburgite formation, which is residual mantle. This formation contains lenses of a separate chromitite-bearing dunite formation. The Morais massif assemblage, at an equivalent structural level, is made up of peridotite and gabbroic/troctolitic cumulates. The chromitite-bearing dunite formation crystallised within small magmatic masses. This chromite crystallisation acted to fractionate the associated Platinum-Group Element (PGE) assemblage. Os, Ir and Ru were incorporated as laurite and irarsite minerals during chromite grain crystallisation, and are located in textural positions from the centres to the margins of the chromite grains. In contrast Pt-bearing arsenides and sulpharsenides started crystallising after the Os, Ir, Ru group, and are only located at the margins of or in between chromite grains. More fractionated assemblages show positive slopes on chondrite normalised whole rock PGE plots. Pd is not directly associated with this fractionation. Instead its mineralisation is associated with that of the base-metal sulphide. Serpentinisation has caused recrystallisation of much original pentlandite to heazlewoodite and magnetite. At the same time Pd-bearing alloys were created, mostly adjacent to sulphide grains with the source of the Pd being in solid solution within the base-metal sulphide. Several factors suggest that the chromite mineralisation was derived from melts of boninitic affinity. The relatively high Pd/Cu ratios calculated for a silicate melt from which the chromite crystallised are consistent with this. The composition of the chromite grains, having 1000r/(Cr+Al) ratios clustering around 75, is typical of boninitic magmas. In addition the refractory composition of the harzburgite formation, and the high tenors of Pd within sulphide, show that it was a possible source for such boninitic melts. The chromite mineralisation took place down to depths of 30km within the mantle wedge of a destructive continental margin.
Minority and religious groups in China : explaining discrepancies in state response
Creators: name: Taynen, Jennifer Emily
Publisher: name: University of British Columbia
Year: 2011

description: The People's Republic of China has long demonstrated significant variation in its treatment of the diverse ethnic and religious minority groups that exist within its borders. Specialists in Chinese Regional Studies, especially those whose research focuses on Chinese ethnic minorities, tend to attribute this discrepancy in policy to ingrained racism or Han-chauvinism within the state apparatus. In contrast, Political Scientists tend to hypothesize that the state varies its policies to respond to groups that show the potential to mobilize and pose a threat to state authority. Here, anticipated observations for each explanation are used to create two models that trace how 1) state racism and 2) perceived mobilization potential would result in the state instituting more repressive controls over a minority group. The critical distinction between the two explanations requires that state attacks (literal or figurative) be identified as either primarily symbolic or primarily strategic. Five cases from the Chinese Communist context are examined with reference to these models. Religious minority status is held as a constant among all the cases selected. Within the cases, variability is found in the levels of ethnic distinctiveness from the Han Chinese majority. While there are many minority groups that could have fit these criteria, the cases highlighted here are the Tibetan Buddhists, the Chinese Buddhists, the Uighur Muslims, the Hui (Chinese) Muslims, and the Falungong. It is concluded that in the first four cases, the strong correlation between levels of ethnic distinctiveness and levels of state repression suggests that state racism plays a significant role in informing state policy, the same does not hold true for the Falungong case, and once state attacks are further broken down into symbolic and strategic actions, there is strong evidence that both state racism and state fear of minority mobilization play a role in informing the Chinese state's actions.
Unexpected Issues for Produce Markets: WTO Decoupling and Domestic Farm Program Design
Creators: name: Thornsbury, Suzanne
name: Schweikhardt, David
name: Woods, Molly
name: Thornsbury, Suzanne
name: Schweikhardt, David
name: Woods, Molly
Publisher: name: Unknown
Year: 2011
Subjects: subject: Farm Management
subject: fruit and vegetable planting restriction
subject: planting flexibility
subject: political economy
subject: supply response

description: Nonprogram crops such as produce are typically considered peripheral to U.S. farm policy discussions, yet impacts of the World Trade Organization decoupling requirement on the fruit and vegetable planting restriction was a major issue in the 2007/08 farm bill. Evolution of planting flexibility in U.S. farm programs has not extended to most specialty crops and Brazil's challenge of cotton support programs highlighted the exception. Despite research results indicating limited diversions of program crop acreage with elimination of the restriction, the political stakes and potential gains from farm policy outcomes were raised considerably for nonprogram crop sectors.
Geometry- and diffraction-independent ionization probabilities in intense laser fields: probing atomic ionization mechanisms with effective intensity matching
Creators: name: Bryan, W. A.
name: Stebbings, S. L.
name: English, E. M. L.
name: Goodworth, T. R. J.
name: Newell, W. R.
name: McKenna, J.
name: Suresh, M.
name: Srigengan, B.
name: Williams, I. D.
name: Turcu, I. C. E.
name: Smith, J. M.
name: Divall, E. J.
name: Hooker, C. J.
name: Langley, A. J.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We report a novel experimental technique for the comparison of ionization processes in ultrafast laser pulses irrespective of pulse ellipticity. Multiple ionization of xenon by 50 fs 790 nm, linearly and circularly polarized laser pulses is observed over the intensity range 10 TW/cm^2 to 10 PW/cm^2 using Effective Intensity Matching (EIM), which is coupled with Intensity Selective Scanning (ISS) to recover the geometry-independent probability of ionization. Such measurements, made possible by quantifying diffraction effects in the laser focus, are compared directly to theoretical predictions of multiphoton, tunnel and field ionization, and a remarkable agreement demonstrated. EIM-ISS allows the straightforward quantification of the probability of recollision ionization in a linearly polarized laser pulse. Furthermore, probability of ionization is discussed in terms of the Keldysh adiabaticity parameter, gamma, and the influence of the precursor ionic states present in recollision ionization is observed for the first time.
description: 10 pages, 5 figures, submitted to Phys. Rev. A on 09-09-05
Coherence and correlation properties of a one-dimensional attractive Fermi gas
Creators: name: Castin, Yvan
name: Carusotto, Iacopo
Publisher: name: arXiv
Year: 2004
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: A recently developed Quantum Monte Carlo algorithm based on the stochastic evolution of Hartree-Fock states has been applied to compute the static correlation functions of a one-dimensional model of attractively interacting two component fermions. The numerical results have been extensively compared to existing approximate approaches. The crossover to a condensate of pairs can be identified as the first-order pair coherence extending throughout the whole size of the system. The possibility of revealing the onset of the transition with other observables such as the density-density correlations or the second-order momentum space correlations is discussed.
First Sources in Infrared Light: Stars, Supernovae and Miniquasars
Creators: name: Cooray, Asantha
name: Yoshida, Naoki
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The cosmic infrared background (IRB) at wavelengths between 1 micron and 3 microns provides a useful probe of early star-formation prior to and during reionization. To explain the high optical depth to electron scattering, as measured by the Wilkinson Microwave Anisotropy Probe (WMAP), one requires significant star-formation activity at redshifts 10 and higher. In addition to massive stars, the IRB flux may be contributed by a population of early miniquasars. We study the relative contributions from first stars, supernovae and quasars to the IRB for reasonable star formation rates at high redshift. If miniquasars radiate efficiently at the Eddington-limit, current background measurements limit the fraction of mass in first stars that is converted to seed black holes to be roughly less than 10%. In the case of supernovae, though an individual supernova is much brighter than the progenitor star, due to the shorter lifetime of order few months, the fractional contribution to the IRB remains at a level of 10% and below when compared to the same contribution from stars. The bright supernovae may, however, be directly detectable by future large ground-based and space telescopes.
description: 8 pages, 3 figures; Revised version based on referee comments
Horizons
Creators: name: Hooft, Gerard 't
Publisher: name: arXiv
Year: 2004
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The gravitational force harbours a fundamental instability against collapse. In standard General Relativity without Quantum Mechanics, this implies the existence of black holes as natural, stable solutions of Einstein's equations. If one attempts to quantize the gravitational force, one should also consider the question how Quantum Mechanics affects the behaviour of black holes. In this lecture, we concentrate on the horizon. One would have expected that its properties could be derived from general coordinate transformations out of a vacuum state. In contrast, it appears that much new physics is needed. Much of that is still poorly understood, but one may speculate on the way information is organized at a horizon, and how refined versions of Quantum Theory may lead to answers.
description: 14 pages LaTeX, 3 Figures PostScript, uses gthstyle.sty (included) Lecture presented at the Erice School for Sub-Nuclear Physics, Sept. 2003
title: A study of wills and will-making in the period 1500-1533 with special reference to the copy wills in the probate registers of the Archdeacon of Bedford 1489-1533
Creators: name: Ford, Judith
Publisher: name: The Open University
Year: 1992

description: Historians sometimes use information derived from sources the nature and function of which they do not fully understand. Wills and testaments from the medieval and early modem periods provide a notable example of this practice; they have been used by historians for the information which they provide on a variety of subjects but have rarely been studied as documents in their own right. As a result, an understanding of the character of wills and testaments and of their utility for the historian has remained limited, and information derived from wills has not always been interpreted satisfactorily. This study involves the detailed examination of a group of Bedfordshire wills made over a thirty-three year period during the early sixteenth century with the intention of promoting a better understanding of this popular source of historical evidence. The seven hundred and eighty wills which form the nucleus of the study are recorded in the first three surviving registers of the court of the Archdeacon of Bedford. The information provided by the wills themselves will be evaluated in the context of the work of historians who have used information derived from wills, both from Bedfordshire and elsewhere, and in the context of early sixteenth-century law and custom. Particular attention is given to the interaction of the last will and testament with the medieval law of succession and to the problems which the complexity of the rules, principles and laws governing the succession to property provide for those who seek to interpret bequests of both personalty and realty.
title: The human dimension of domestic energy use : an integrated approach
Creators: name: Hitchcock, Guy St John
Publisher: name: The Open University
Year: 1995

description: Domestic energy consumption is a multifaceted phenomenon which is dependent on both the social and technical characteristics of domestic households. In this thesis it is argued that such a phenomenon is best understood using an integrated approach, combining both the physical and social theories of energy use. Such an integrated approach is developed with the use of systems theory and focuses on the interaction between the physical and social aspects of the household. This integrated approach is used to analyse UK and US domestic energy consumption patterns and is compared with a purely physical and a purely social analysis. These analyses also highlight the inadequacies of the physical or social approach and demonstrates the difficulty involved in trying to consider both in a single integrated analysis.
On the mass of the Ds(0+,1+) system
Creators: name: Deandrea, A.
name: Nardulli, G.
name: Polosa, A. D.
Publisher: name: arXiv
Year: 2003
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In this note we discuss a determination for the mass of the Ds(0+,1+) system recently discovered by the BaBar, CLEO II and Belle Collaborations. The value of the mass is derived by making explicit the prediction obtained in a quark-meson model prior to the discovery of these states.
description: 3 pages, revtex
title: Porphyrin metabolism in congenital erythropoietic porphyria
Creators: name: Guo, Rong
Publisher: name: The Open University
Year: 1992

description: Meso-hydroxyuroporphyrin I, B-hydroxypropionic acid uroporphyrin I, hydroxyacetic acid uroporphyrin I and peroxyacetic acid uroporphyrin I have been isolated from the urine and plasma of patients with congenital erythropoietic porphyria (CEP) by high-performance liquid chromatography and characterized by liquid secondary ion mass spectrometry and chemical properties. The physico-chemical properties of these compounds have been studied. The hydroxy- and peroxyacetic acid- uroporphyrin I derivatives are the true metabolites of uroporphyrinogen I in vivo and their presence in urine and plasma is a common feature of CEP. The absence of these derivatives in duodenal aspirate and faeces suggests that they are of erythropoietic origin. The mechanism of formation of the hydroxy- and peroxyacetic acid- uroporphyrin I has been investigated. Peroxyacetic acid uroporphyrin I is formed from uroporphyrinogen I in the presence of H202 and iron while the hydroxylated uroporphyrin I derivatives are most probably produced by hydroxyl radicals generated during the formation of peroxyacetic acid uroporphyrin I. Destruction of porphyrins is found in the same reaction and can be prevented bydesferrioxamine, indicating that it is due to hydroxyl radicals. The formation of peroxyacetic acid- and hydroxyuroporphyrin I derivatives are uroporphyrinogen I concentration dependent. These derivatives can only be formed when uroporphyrinogen I is accumulated to a certain concentration (approx. 1-2 ~M) and the formation is then proportional to the uroporphyrinogen I concentration. The peroxylation reaction has been shown to take place only at the acetic acid side-chains of porphyrinogen and not at the propionic acid side-chains. The peroxylation reaction can therefore take place whenever a porphyrinogen with an acetic acid substituent is accumulated. Oral charcoal therapy failed to reduce the porphyrins accumulated in vivo in a patient with CEP. Uroporphyrin I, the major porphyrin accumulating in CEP, was not excreted into bile and interruption of the enterohepatic circulation by binding porphyrins onto charcoal therefore does not benefit CEP. It may, however, be effective in the treatment of hepatic porphyrias in which the accumulated porphyrins are mainly excreted via the gut lumen.