Precious metals, a shiny hedge for investors?

Recorrendo a duas abordagens diferentes, regressão e correlação, e cobrindo os últimos vinte anos de dados diários para sete países, esta tese investiga as propriedades “safe haven” e “hedge” dos metais preciosos, em comparação com acções internacionais para um dado estado da economia. Adicionalmente, esta tese avalia o desempenho de diferentes portfolios, dentro e fora da amostra, com o objectivo de verificar se o investimento em metais preciosos poderá ajudar a atenuar a gestao do risco por parte do investidor. Os principais resultados são os que se seguem: (i) O ouro é o melhor metal precioso para um “hedging” internacional em oposição às acções (ii) O ouro permite obter valiosos benefícios de gestão de risco do portfolio (iii) 60/40 dos portofios atribuidos com ouro permitem ao investidor obter bons resultados.

Aplicaciones interactivas diseñadas con Shiny

Recientemente, el software estadístico R ha incluido en su repositorio un paquete de instrucciones llamado Shiny que permite la creación de aplicaciones web interactivas. En este trabajo, presentamos unos recursos docentes diseñados con Shiny que ponen al alcance de los alumnos tantos ejercicios como deseen, permitiéndoles entrenar sus capacidades matemáticas y estadísticas de manera individual desde su propia casa.

Using the R package Shiny to create web applications that facilitate quantitative gene expression analysis

Thesis (Master's)--University of Washington, 2016-06

Implementation of a computerized assessment system by using backpropagation neural networks with R and shiny

Las dificultades a las que los estudiantes se enfrentan y su lucha por dominar los temas, podría aumentar como consecuencia de la inadecuada utilización de materiales de evaluación. Generalmente se encuentran en el aula alumnos que hacen buen uso del material de los cursos y de una manera rápida, mientras que otros presentan dificultades con el aprendizaje del material. Esta situación es fácilmente visto en los resultados de los exámenes, un grupo de estudiantes podrían obtener buenas calificaciones animándoles, mientras que otros obtendrían la mala percepción de que los temas son difíciles, y en algunos casos, obligándolos a abandonar el curso o en otros casos a cambiar de carrera. Creemos que mediante el uso de técnicas de aprendizaje automático, y en nuestro caso la utilización de redes neuronales, sería factible crear un entorno de evaluación que podrían ajustarse a las necesidades de cada estudiante. Esto último disminuiría la sensación de insatisfacción de los alumnos y el abandono de los cursos.

Uso do R-shiny para execução de modelos matemáticos via web: estudo de caso sobre a dinâmica de propagação do HLB do citros.

RESUMO - O Huanglongbing (HLB ou Greening) é a doença mais importante e destrutiva da citricultura mundial. Presente de forma endêmica nos continentes asiático e africano há várias décadas, essa doença foi constatada no Brasil em 2004, sendo transmitida pelo psilídeo Diaphorina citri e causada por bactérias de floema Candidatus Liberibacter spp. Para auxiliar o estudo da doença, foram desenvolvidos modelos matemáticos para avaliação da propagação do HLB Citros. Este trabalho tem por objetivo a criação de um sistema para execução via web de um destes modelos, permitindo aos profissionais de diversas formações, em especial os das áreas biológicas, que são os especialistas do domínio em estudo, acesso rápido aos resultados fornecidos pelo modelo matemático, eliminando ainda a necessidade de conhecimento prévio em alguma linguagem de programação ou de métodos de resolução de equações diferenciais. O sistema foi completamente implementado em R, tendo sido o pacote deSolve usado para solução do modelo matemático e o framework web Shiny para a interface com usuário, sendo todos open source.

AITPM Email Newsletter Volume 0910, October 2009 : Presidents Message

President’s Message Hello fellow AITPM members, Well I can’t believe it’s already October! My office is already organising its end of year function and looking to plan for 2010. Our whole School is moving to a different building next year, with the lovely L block eventually making way for a new shiny one. Those of you who have entered the Brisbane CBD from the south side, across the Captain Cook Bridge, would know L block as the big 9 storey brick and concrete Lego block ode to 1970’s functional architecture, which greets you on the right hand side. Onto traffic matters: an issue that has been tossing around in my mind of late is that of speed. I know I am growing older and may be prematurely becoming a “grumpy old man”, but everyone around me locally seems to be accelerating off from the stop line much faster than I was taught to for economical driving, both here and in the United States (yes they made my wife and me resit our written and practical driving tests when we lived there). People here in Australia also seem to be driving right on top of the posted speed limit, on whichever part of the Road Hierarchy, whether urban or rural. I was also taught on both sides of the planet that the posted speed limit is a maximum legal speed, not the recommended driving speed. This message did seem to sink in to the American drivers around me when we lived in Oregon - where people did appear to drive more cautiously. Further, posted speed limits in Oregon were, and I presume still are, set more conservative by about 5mph or 10km/h than Australian limits, for any given part of the Road Hierarchy. Another excellent speed limit treatment used in Oregon was in school zones, where reduced speed limits applied “when children are present” rather than during prescribed hours on school days. This would be especially useful here in Australia, where a lot of extra-curricular activities take place around schools outside of the prescribed speed limit hours. Before and after hours school care is on the increase (with parents dropping and collecting children near dawn and dusk in the winter), and many childcentred land uses are located adjacent to schools, such as Scouts/Guides halls, swimming pools and parks. Consequentially, I believe there needs to be some consideration towards more public campaigning about economical driving and the real purpose of the speed limit = or perhaps even a rethink of the speed limit concept, if people really are driving on top of it and it’s not just me becoming grumpier (our industrial psychology friends at the research centres may be able to assist us here). The Queensland organising committee is now in full swing organising the 2010 AITPM National Conference, What’s New?, so please keep a lookout for related content. Best regards to all, Jon Bunker PS A Cartoonists view of traffic engineers I thought you might enjoy this. http://xkcd.com/277/

‘Supersize me’ : on equine obesity

There’s nothing like travel to broaden the mind. As a young man living in Britain during the 1980s I thought I knew about human obesity, but it took a visit to the US to show me what an epidemic looks like. Nowadays I live in Australia, where human obesity is rife. We have plenty of fat horses too (Sillence et al., 2006), but they are noticeable. In fact, it was only recently during a return visit to Britain, that I was finally sold on the concept of an equine obesity epidemic. It seems that in the UK, the fat horse or pony is now so commonplace that it has come to represent the norm in the eyes of many owners. I met clinicians who claim to have forgotten what a fit horse looks like, and heard anecdotes of a responsible owner who kept their animals in a healthy body condition, only to be reported to the RSPCA for ‘cruelty’. Round and shiny have become the order of the day and, as we have learned from the tsunami of human obesity, once a problem reaches a certain scale it can seem unstoppable, despite the attendant risks, costs and consequences.

Drawing and writing on the screen

This chapter focuses on the physicality of the iPad as an object, and how that physicality affects the interactions children have with the device generally, and the apps specifically. Thinking about the physicality of the iPad is important because the materials, size, weight and appearance make the iPad quite unlike most other toys and equipment in the kindergarten space. Most strikingly, this physicality does not ‘represent’ the virtual vast dimensions of the iPad brought about through the diverse functions and contents of the apps contained in it. While the iPad is small enough and functional enough to be easily handled and operated even by young children, it is capable of performing highly complex, highly technological tasks that take it beyond its diminutive dimensions. This virtual-actual contrast is interesting to consider in relation to the other resources more commonly found in a kindergarten space. While objects such as toys, bricks, building materials often do prompt the child to imagine and invent beyond the physical boundaries of the toy, they not have the same types of virtual-actual contrasts of a digital device such as the iPad. How then, might children be drawn to the iPad because of its physical, technological and virtual difference? Particularly, how might this virtual-actual difference impact on the physical skills associated with writing and drawing: skills usually learnt through the use of a pencil and paper? While the research project did not set out to compare how digital and paper-based resources affect writing and drawing skills there was great interest to see how young children negotiated drawing and writing on the shiny glass surface of the iPad.

Study of the reaction between 1,2,3-trihydroxybenzene and 8-hydroxyquinoline in the solid state

1.2,3-Trihydroxybenzene (THB) reacts with 8-hydroxyquinoline (8HQ) in the solid state forming an orange-coloured charge transfer complex THB* (8HQ)(2). When the reaction was carried out in a petri dish, or when the vapours of 8HQ were allowed to react with solid THB (gravimetric study), the reaction product separated out as good quality, shiny single crystals. X-Ray diffraction studies on single crystals showed that they belong to the orthorhombic system with a = 15.408(1), b = 16.276(1), c = 7.825(1) Angstrom, Z = 4, D-x = 1.413 g cm(-3) and space group Pnaa. From the crystallographic evidence it has been found that the proton of the middle OH group of THB is transferred to the N atom of 8HQ. This accounts for the observed colour change. Kinetic studies on the solid state reaction showed that the 8HQ molecules diffuse towards THB, and the lateral diffusion occurs through surface migration, grain boundary diffusion and vapour phase diffusion. Gravimetric studies of the reaction between solid THB and 8HQ vapour showed that the diffusion of 8HQ molecules into the crystal lattice of THB has a higher energy of activation than that observed when the reactants are in contact. The nature of the crystal packing in the reaction product indicates diffusion of 8HQ molecules into the crystal lattice of THB along the c-axis, to occupy the cavities present between the THB molecules in the unit cell.

Low-pressure MOCVD of Al2O3 films using aluminium acetylacetonate as precursor: nucleation and growth

A study of the deposition of aluminium oxide films by low-pressure metalorganic chemical vapour deposition from the complex aluminium acetylacetonate, in the absence of an oxidant gas, has been carried out. Depositions on to Si(100), stainless steel, and TiN-coated cemented carbide are found to be smooth, shiny, and blackish. SIMS, XPS and TEM analyses reveal that films deposited at temperatures as low as 600 degreesC contain small crystallites Of kappa-Al2O3, embedded in an amorphous matrix rich in graphitic carbon. Optical and scanning electron microscopy reveal a surface morphology made up of spherulites that suggests that film growth might involve a melting process. A nucleation and growth mechanism, involving the congruent melting clusters of precursor molecules on the hot substrate surface, is therefore invoked to explain these observations. An effort has been made experimentally to verify this proposed mechanism. (C) 2002 Elsevier Science B.V. All rights reserved.

A study of Al2O3:C films on Si(100) grown by low pressure MOCVD

We report the characterization of carbonaceous aluminium oxide, Al2O3:C, films grown on Si(100) by metalorganic chemical vapor deposition. The focus is on the study of the effects of carbon on the dielectric properties of aluminium oxide in a qualitative manner. The carbon present in the aluminium oxide film derives from aluminium acetylacetonate used as the source of aluminium. As-grown films comprise nanometer-sized grains of alumina (∼ 20–50 nm) in an amorphous carbonaceous matrix, as examined by X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The films are shiny; they are smooth as observed by scanning electron microscopy (SEM). An attempt has been made to explore the defects (viz., oxide charge density) in the aluminium oxide films using room temperature high frequency capacitance – voltage (C-V) and current–voltage (I-V) measurements. The hysteresis and stretch-out in the high frequency C-V plots is indicative of charge trapping. The role of heteroatoms, as characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy, in the transport of charge in Al2O3:C films is discussed.

Effects of Highlights on Gloss Perception

The perception of a glossy surface in a static monochromatic image can occur when a bright highlight is embedded in a compatible context of shading and a bounding contour. Some images naturally give rise to the impression that a surface has a uniform reflectance, characteristic of a shiny object, even though the highlight may only cover a small portion of the surface. Nonetheless, an observer may adopt an attitude of scrutiny in viewing a glossy surface, whereby the impression of gloss is partial and nonuniform at image regions outside of a higlight. Using a rating scale and small probe points to indicate image locations, differential perception of gloss within a single object is investigate in the present study. Observers' gloss ratings are not uniform across the surface, but decrease as a function of distance from highlight. When, by design, the distance from a highlight is uncoupled from the luminance value at corresponding probe points, the decrease in rated gloss correlates more with the distance than with the luminance change. Experiments also indicate that gloss ratings change as a function of estimated surface distance, rather than as a function of image distance. Surface continuity affects gloss ratings, suggesting that apprehension of 3D surface structure is crucial for gloss perception.

AMERICAN WOMEN COMPOSERS: SELECTED PUBLISHED WORKS FOR FLUTE AND PIANO AND FOR UNACCOMPANIED FLUTE COMPOSED BETWEEN 1930 AND 2008

The music of women composers often comprises only a small percentage of flutists‘ repertoire, yet there are actually many active women composers, many of whom have written for the flute. The aim of this dissertation is to chronicle a selection of works by several American women composers that have contributed to accessible flute repertoire. For the purpose of this dissertation, accessibility is described by the following parameters: works that limit the use of extended techniques, works that are suitable for performers from high school through a reasonably advanced level, works that are likely to elicit emotionally musical communication from the performer to the listener, and works that are reasonably available through music stores or outlets on the Internet that have a fairly comprehensive reach to the general public. My subjective judgment also played a role in the final selection of the 25 works included as part of this dissertation, and performed on three musically well-balanced recitals. A variety of resources were consulted for the repertoire, including Boenke‘s Flute Music by Women Composers: An Annotated Catalog, and the catalogs of publishers such as Arsis Press and Hildegard Publishing, both of which specialize in the music of women composers. The works performed and discussed are the following: Adrienne Albert – Sunswept; Marion Bauer – Prelude and Fugue, Op. 43.; Marilyn Bliss – Lament; Ann Callaway – Updraft; Ruth Crawford – Diaphonic Suite; Emma Lou Diemer – Sonata; Vivian Fine – Emily’s Images; Cynthia Folio – Arca Sacra; Nancy Galbraith – Atacama; Lita Grier – Sonata; Jennifer Higdon – The Jeffrey Mode; Edie Hill – This Floating World; Katherine Hoover – Masks; Mary Howe – Interlude between Two Pieces; Laura Kaminsky – Duo; Libby Larsen – Aubade; Alex Shapiro – Shiny Kiss; Judith Shatin – Coursing Through the Still Green; Faye-Ellen Silverman – Taming the Furies; Augusta Read Thomas – Euterpe’s Caprice; Joan Tower – Valentine Trills; Ludmila Ulehla – Capriccio; Elizabeth Vercoe – Kleemation; Gwyneth Walker – Sonata; and Judith Lang Zaimont – ‘Bubble-Up’ Rag. All of these works are worthy alternatives to the more frequently played flute repertoire, and they serve as a good starting point for anyone interested i n exploring the works of women composers.

Spectroscopic Investigation of Tooth Caries and Demineralization

Dental caries persists to be the most predominant oral disease in spite of remarkable progress made during the past half- century to reduce its prevalence. Early diagnosis of carious lesions is an important factor in the prevention and management of dental caries. Conventional procedures for caries detection involve visual-tactile and radiographic examination, which is considered as “gold standard”. These techniques are subjective and are unable to detect the lesions until they are well advanced and involve about one-third of the thickness of enamel. Therefore, all these factors necessitate the need for the development of new techniques for early diagnosis of carious lesions. Researchers have been trying to develop various instruments based on optical spectroscopic techniques for detection of dental caries during the last two decades. These optical spectroscopic techniques facilitate noninvasive and real-time tissue characterization with reduced radiation exposure to patient, thereby improving the management of dental caries. Nonetheless, a costeffective optical system with adequate sensitivity and specificity for clinical use is still not realized and development of such a system is a challenging task.Two key techniques based on the optical properties of dental hard tissues are discussed in this current thesis, namely laser-induced fluorescence (LIF) and diffuse reflectance (DR) spectroscopy for detection of tooth caries and demineralization. The work described in this thesis is mainly of applied nature, focusing on the analysis of data from in vitro tooth samples and extending these results to diagnose dental caries in a clinical environment. The work mainly aims to improve and contribute to the contemporary research on fluorescence and diffuse reflectance for discriminating different stages of carious lesions. Towards this, a portable and compact laser-induced fluorescence and reflectance spectroscopic system (LIFRS) was developed for point monitoring of fluorescence and diffuse reflectance spectra from tooth samples. The LIFRS system uses either a 337 nm nitrogen laser or a 404 nm diode laser for the excitation of tooth autofluorescence and a white light source (tungsten halogen lamp) for measuring diffuse reflectance.Extensive in vitro studies were carried out on extracted tooth samples to test the applicability of LIFRS system for detecting dental caries, before being tested in a clinical environment. Both LIF and DR studies were performed for diagnosis of dental caries, but special emphasis was given for early detection and also to discriminate between different stages of carious lesions. Further the potential of LIFRS system in detecting demineralization and remineralization were also assessed.In the clinical trial on 105 patients, fluorescence reference standard (FRS) criteria was developed based on LIF spectral ratios (F500/F635 and F500/F680) to discriminate different stages of caries and for early detection of dental caries. The FRS ratio scatter plots developed showed better sensitivity and specificity as compared to clinical and radiographic examination, and the results were validated with the blindtests. Moreover, the LIF spectra were analyzed by curve-fitting using Gaussian spectral functions and the derived curve-fitted parameters such as peak position, Gaussian curve area, amplitude and width were found to be useful for distinguishing different stages of caries. In DR studies, a novel method was established based on DR ratios (R500/R700, R600/R700 and R650/R700) to detect dental caries with improved accuracy. Further the diagnostic accuracy of LIFRS system was evaluated in terms of sensitivity, specificity and area under the ROC curve. On the basis of these results, the LIFRS system was found useful as a valuable adjunct to the clinicians for detecting carious lesions.