EARLY TWENTIETH CENTURY VIOLA MUSIC FROM ENGLAND AND GERMANY: FROM POST-ROMANTICISM TO MODERNISM

In the early twentieth century, the viola began to gain status as a solo instrument with the appearance in England of the virtuosic violist Lionel Tertis. Because of a lack of music for viola at that time, such English composers as York Bowen, Arnold Bax, Ralph Vaughan Williams, Arthur Bliss and William Walton began to write viola music for Tertis. Meanwhile, in Germany, the well-known composer and virtuosic violinist and violist Paul Hindemith wrote and premiered several viola sonatas and concertos. Viola music became even more developed later with William Primrose, the legendary Scottish violist, and all the works written in the early twentieth century have remained significant in the viola literature. Although this new viola music appeared in both countries during same period, it developed along different lines in each country. Because they were under the influence of earlier periods and traditions, the English composers who associated with Tertis wrote their music in a Romantic style, with expanded harmony, various colors of sound and timbre, and lyrical melodies. Hindemith, as a composer himself, employed a more Modernist style, using atonality and angular melodies, which represented German trends at that time. I have given three recitals, of which the first two were divided between selected English music and German music. Although I originally intended to focus solely on music by Hindemith and music written for Terts, I decided that in order to give a more complete view of the national trends of those two countries, I included Rebecca Clarke's Sonata, Lachrymae by Benjamin Britten (dedicated to William Primrose), and Max Reger's Suite for Viola. Rebecca Clarke was herself a fine violist, and her sonata's Romantic style is also representative of the English trends of viola music. Lachrymae was written with a different concept and shows more modernity than had ever before occurred in England, though it still differs from the modernity of other countries. Max Reger's Suite is in a truly Romantic style, yet it is old fashioned in ways that differ not only from Wagner or Strauss, but also from English music of the period. In my last recital I wished to pay homage to Tertis, with a program consisting entirely of music written for him. For the finale, Arthur Bliss's Viola Sonata was especially chosen because it provides interesting similarities and contrasts with earlier English music in the Romantic style.

Effects of chronic mild traumatic brain injury on white matter integrity in iraq and afghanistan war veterans

Mild traumatic brain injury (TBI) is a common source of morbidity from the wars in Iraq and Afghanistan. With no overt lesions on structural MRI, diagnosis of chronic mild TBI in military veterans relies on obtaining an accurate history and assessment of behavioral symptoms that are also associated with frequent comorbid disorders, particularly posttraumatic stress disorder (PTSD) and depression. Military veterans from Iraq and Afghanistan with mild TBI (n = 30) with comorbid PTSD and depression and non-TBI participants from primary (n = 42) and confirmatory (n = 28) control groups were assessed with high angular resolution diffusion imaging (HARDI). White matter-specific registration followed by whole-brain voxelwise analysis of crossing fibers provided separate partial volume fractions reflecting the integrity of primary fibers and secondary (crossing) fibers. Loss of white matter integrity in primary fibers (P < 0.05; corrected) was associated with chronic mild TBI in a widely distributed pattern of major fiber bundles and smaller peripheral tracts including the corpus callosum (genu, body, and splenium), forceps minor, forceps major, superior and posterior corona radiata, internal capsule, superior longitudinal fasciculus, and others. Distributed loss of white matter integrity correlated with duration of loss of consciousness and most notably with "feeling dazed or confused," but not diagnosis of PTSD or depressive symptoms. This widespread spatial extent of white matter damage has typically been reported in moderate to severe TBI. The diffuse loss of white matter integrity appears consistent with systemic mechanisms of damage shared by blast- and impact-related mild TBI that involves a cascade of inflammatory and neurochemical events. © 2012 Wiley Periodicals, Inc.

Monte Carlo Analysis and Physics Characterization of a Novel Nanoparticle Detector for Medical and Micro-dosimetry Applications

The outcomes for both (i) radiation therapy and (ii) preclinical small animal radio- biology studies are dependent on the delivery of a known quantity of radiation to a specific and intentional location. Adverse effects can result from these procedures if the dose to the target is too high or low, and can also result from an incorrect spatial distribution in which nearby normal healthy tissue can be undesirably damaged by poor radiation delivery techniques. Thus, in mice and humans alike, the spatial dose distributions from radiation sources should be well characterized in terms of the absolute dose quantity, and with pin-point accuracy. When dealing with the steep spatial dose gradients consequential to either (i) high dose rate (HDR) brachytherapy or (ii) within the small organs and tissue inhomogeneities of mice, obtaining accurate and highly precise dose results can be very challenging, considering commercially available radiation detection tools, such as ion chambers, are often too large for in-vivo use.

In this dissertation two tools are developed and applied for both clinical and preclinical radiation measurement. The first tool is a novel radiation detector for acquiring physical measurements, fabricated from an inorganic nano-crystalline scintillator that has been fixed on an optical fiber terminus. This dosimeter allows for the measurement of point doses to sub-millimeter resolution, and has the ability to be placed in-vivo in humans and small animals. Real-time data is displayed to the user to provide instant quality assurance and dose-rate information. The second tool utilizes an open source Monte Carlo particle transport code, and was applied for small animal dosimetry studies to calculate organ doses and recommend new techniques of dose prescription in mice, as well as to characterize dose to the murine bone marrow compartment with micron-scale resolution.

Hardware design changes were implemented to reduce the overall fiber diameter to <0.9 mm for the nano-crystalline scintillator based fiber optic detector (NanoFOD) system. Lower limits of device sensitivity were found to be approximately 0.05 cGy/s. Herein, this detector was demonstrated to perform quality assurance of clinical 192Ir HDR brachytherapy procedures, providing comparable dose measurements as thermo-luminescent dosimeters and accuracy within 20% of the treatment planning software (TPS) for 27 treatments conducted, with an inter-quartile range ratio to the TPS dose value of (1.02-0.94=0.08). After removing contaminant signals (Cerenkov and diode background), calibration of the detector enabled accurate dose measurements for vaginal applicator brachytherapy procedures. For 192Ir use, energy response changed by a factor of 2.25 over the SDD values of 3 to 9 cm; however a cap made of 0.2 mm thickness silver reduced energy dependence to a factor of 1.25 over the same SDD range, but had the consequence of reducing overall sensitivity by 33%.

For preclinical measurements, dose accuracy of the NanoFOD was within 1.3% of MOSFET measured dose values in a cylindrical mouse phantom at 225 kV for x-ray irradiation at angles of 0, 90, 180, and 270˝. The NanoFOD exhibited small changes in angular sensitivity, with a coefficient of variation (COV) of 3.6% at 120 kV and 1% at 225 kV. When the NanoFOD was placed alongside a MOSFET in the liver of a sacrificed mouse and treatment was delivered at 225 kV with 0.3 mm Cu filter, the dose difference was only 1.09% with use of the 4x4 cm collimator, and -0.03% with no collimation. Additionally, the NanoFOD utilized a scintillator of 11 µm thickness to measure small x-ray fields for microbeam radiation therapy (MRT) applications, and achieved 2.7% dose accuracy of the microbeam peak in comparison to radiochromic film. Modest differences between the full-width at half maximum measured lateral dimension of the MRT system were observed between the NanoFOD (420 µm) and radiochromic film (320 µm), but these differences have been explained mostly as an artifact due to the geometry used and volumetric effects in the scintillator material. Characterization of the energy dependence for the yttrium-oxide based scintillator material was performed in the range of 40-320 kV (2 mm Al filtration), and the maximum device sensitivity was achieved at 100 kV. Tissue maximum ratio data measurements were carried out on a small animal x-ray irradiator system at 320 kV and demonstrated an average difference of 0.9% as compared to a MOSFET dosimeter in the range of 2.5 to 33 cm depth in tissue equivalent plastic blocks. Irradiation of the NanoFOD fiber and scintillator material on a 137Cs gamma irradiator to 1600 Gy did not produce any measurable change in light output, suggesting that the NanoFOD system may be re-used without the need for replacement or recalibration over its lifetime.

For small animal irradiator systems, researchers can deliver a given dose to a target organ by controlling exposure time. Currently, researchers calculate this exposure time by dividing the total dose that they wish to deliver by a single provided dose rate value. This method is independent of the target organ. Studies conducted here used Monte Carlo particle transport codes to justify a new method of dose prescription in mice, that considers organ specific doses. Monte Carlo simulations were performed in the Geant4 Application for Tomographic Emission (GATE) toolkit using a MOBY mouse whole-body phantom. The non-homogeneous phantom was comprised of 256x256x800 voxels of size 0.145x0.145x0.145 mm3. Differences of up to 20-30% in dose to soft-tissue target organs was demonstrated, and methods for alleviating these errors were suggested during whole body radiation of mice by utilizing organ specific and x-ray tube filter specific dose rates for all irradiations.

Monte Carlo analysis was used on 1 µm resolution CT images of a mouse femur and a mouse vertebra to calculate the dose gradients within the bone marrow (BM) compartment of mice based on different radiation beam qualities relevant to x-ray and isotope type irradiators. Results and findings indicated that soft x-ray beams (160 kV at 0.62 mm Cu HVL and 320 kV at 1 mm Cu HVL) lead to substantially higher dose to BM within close proximity to mineral bone (within about 60 µm) as compared to hard x-ray beams (320 kV at 4 mm Cu HVL) and isotope based gamma irradiators (137Cs). The average dose increases to the BM in the vertebra for these four aforementioned radiation beam qualities were found to be 31%, 17%, 8%, and 1%, respectively. Both in-vitro and in-vivo experimental studies confirmed these simulation results, demonstrating that the 320 kV, 1 mm Cu HVL beam caused statistically significant increased killing to the BM cells at 6 Gy dose levels in comparison to both the 320 kV, 4 mm Cu HVL and the 662 keV, 137Cs beams.

A regularized iterative algorithm for limited-angle inverse Radon transform

The tomography problem is investigated when the available projections are restricted to a limited angular domain. It is shown that a previous algorithm proposed for extrapolating the data to the missing cone in Fourier space is unstable in the presence of noise because of the ill-posedness of the problem. A regularized algorithm is proposed, which converges to stable solutions. The efficiency of both algorithms is tested by means of numerical simulations. © 1983 Taylor and Francis Group, LLC.

Infrared light on molecule-molecule and molecule-surface collisions

By analyzing measured infrared absorption of pure CH4 gas under both "free" (large sample cell) and "confined" (inside the pores of a silica xerogel sample) conditions we give a demonstration that molecule-molecule and molecule-surface collisions lead to very different propensity rules for rotational-state changes. Whereas the efficiency of collisions to change the rotational state (observed through the broadening of the absorption lines) decreases with increasing rotational quantum number J for CH4-CH4 interactions, CH4-surface collisions lead to J-independent linewidths. In the former case, some (weak) collisions are inefficient whereas, in the latter case, a single collision is sufficient to remove the molecule from its initial rotational level. Furthermore, although some gas-phase collisions leave J unchanged and only modify the angular momentum orientation and/or symmetry of the level (as observed through the spectral effects of line mixing), this is not the case for the molecule-surface collisions since they always change J (in the studied J=0-14 range).

La transformación de rotación en el espacio: diseño curricular e integración en el aula del ambiente de geometría dinámica Cabri 3D

Se busca generar una discusión sobre el proceso de diseño y sistematización de una experiencia de aula en la cual se integra el Ambiente de Geometría Dinámica (AGD) Cabri 3D en el aprendizaje de la transformación de rotación en el espacio. En nuestra propuesta, encontramos investigaciones importantes en didáctica de las matemáticas que han puesto en evidencia las dificultades que los estudiantes presentan comúnmente en la exploración de propiedades de los objetos geométricos en el espacio, e incluso la representación de los mismos en él. Por lo cual, la comunicación se apoya en una aproximación instrumental que busca dar cuenta del papel mediador de Cabri 3D como un instrumento construido por el sujeto en el contexto de aprendizaje de la geometría. La propuesta se basa en el diseño de una situación didáctica en la que se integra el AGD Cabri 3D; hemos introducido una categoría que caracteriza el objeto matemático a movilizar en la secuencia de situaciones didácticas, esta categoría es la transformación de rotación en el espacio. La primera caracterización debe darse desde el reconocimiento de la Geometría transformacional como una alternativa para que los estudiantes construyan conocimiento del espacio a partir de la exploración y actuación sobre el mismo, así en la propuesta de la secuencia didáctica se tomara en consideración que la transformación de rotación posibilita la exploración de aspectos complejos tales como el sentido, la magnitud angular y la invarianza de propiedades. Esta última (la invarianza de propiedades) es uno de los aspectos más importante que se deberán distinguir en el diseño de la secuencia didáctica; en la composición de rotaciones por ejemplo, se reconoce como importante que los estudiantes tengan la capacidad de poder determinar cuáles objetos geométricos, puestos en juego en la transformación, conservan sus propiedades, así como poder determinar dentro de la rotación qué se conserva invariante. La segunda caracterización es el reconocimiento de la visualización como medio para que el estudiante interprete la información gráfica de conceptos matemáticos que se le presentan, con el fin de resolver un problema y realizar conjeturas acerca de la noción matemática que está trabajando. La pregunta central para animar la discusión en torno a nuestra comunicación es la siguiente: ¿Cómo influye el uso de Cabri 3D en el estudio del espacio y la exploración de la noción de transformación de rotación en el espacio?, ¿En la organización de la clase y los dispositivos que se deben implementar en la misma?

Propuesta de entorno computacional como apoyo a la enseñanza de las matemáticas

El cálculo diferencial e integral, es materia obligada en gran parte del currículo escolar y piedra angular en el desarrollo de la matemática. A pesar de ello en escuelas tanto a nivel medio como superior, los reportes de problemas en su enseñanza aprendizaje son frecuentes. Esta materia presenta un alto índice de reprobación, inclusive con alumnos que recursan. Este estudio muestra una fuerte tendencia, en la educación, a visualizar el cálculo como un patrón de fórmulas y procedimientos algebraicos, dejando fuera los aspectos conceptuales. En el mismo sentido Dreyfus (1990, 124), reporta que las investigaciones en Francia exhiben la tendencia de los estudiantes a los aspectos de procedimiento algorítmicos, dejando fuera los conceptuales.

Using EMGs and kinematics data to study the take-off technique of experts and novices for a pole vaulting short run-up educational exercise

This study attempts to characterise the electromyographic activity and kinematics exhibited during the performance of take-off for a pole vaulting short run-up educational exercise, for different expertise levels. Two groups (experts and novices) participated in this study. Both groups were asked to execute their take-off technique for that specific exercise. Among the kinematics variables studied, the knee, hip and ankle angles and the hip and knee angular velocities were significantly different. There were also significant differences in the EMG variables, especially in terms of (i) biceps femoris and gastrocnemius lateralis activity at touchdown and (ii) vastus lateralis and gastrocnemius lateralis activity during take-off. During touchdown, the experts tended to increase the stiffness of the take-off leg to decrease braking. Novices exhibited less stiffness in the take-off leg due to their tendency to maintain a tighter knee angle. Novices also transferred less energy forward during take-off due to lack of contraction in the vastus lateralis, which is known to contribute to forward energy transfers. This study highlights the differences in both groups in terms of muscular and angular control according to the studied variables. Such studies of pole vaulting could be useful to help novices to learn expert's technique.

Global and local contributions to the optical specification of time to contact: Observer sensitivity to composite tau

First-order time remaining until a moving observer will pass an environmental element is optically specified in two different ways. The specification provided by global tau (based on the pattern of change of angular bearing) requires that the element is stationary and that the direction of motion is accurately detected, whereas the specification provided by composite tau (based on the patterns of change of optical size and optical distance) does not require either of these. We obtained converging evidence,for our hypothesis. that observers are sensitive to composite tau in four experiments involving, relative judgments of, time to, passage with forced-choice methodology. Discrimination performance was enhanced in the presence of a local expansion component, while being unaffected when the detection of the direction of heading was impaired. Observers relied on the information carried in composite tau rather than on the information carried in its constituent components. Finally, performance was similar under conditions of observer motion and conditions of object motion. Because composite tau specifies first-order time remaining for a large number of situations, the different ways in which it may be detected are discussed.

Revisited: the inertia tensor as a proprioceptive invariant in humans

A multitude of tasks that we perform on a daily basis require precise information about the orientation of our limbs with respect to the environment and the objects located within it. Recent studies have suggested that the inertia tensor, a physical property whose values are time- and co-ordinate-indepenclent, may be an important informational invariant used by the proprioceptive system to control the movements of our limbs (Pagano et al., Ecol. Psychol. 8 (1996) 43; Pagano and Turvey, Percept. Psychophys. 52 (1992) 617; Pagano and Turvey, J. Exp. Psychol. Hum. Percept. Perform. 21 (1995) 1070). We tested this hypothesis by recording the angular errors made by subjects when pointing to virtual targets in the dark. Close examination of the pointing errors made did not show any significant effects of the inertia tensor modifications on pointing accuracy. The kinematics of the pointing movements did not indicate that any on-line adjustments were being made to compensate for the inertia tensor changes. The implications of these findings with respect to the functioning of the proprioceptive system are discussed.

Enhancement of optically thick to thin line intensities in solar and stellar coronal plasmas through radiative transfer effects: an angularly resolved study.

An analysis of radiative transfer effects present in the Fe XV ion stage of solar and stellar coronal plasmas provides a general explanation of line radiation intensity enhancement above the optically thin limit. Full linearization radiation transfer is compared with the escape factor method and found to be in good agreement at the lower column densities. An angular study of the enhancement shows that symmetry factors are of great importance. This gives a possible reason for the indeterminate status of opacity in relation to coronal lines of distant stellar sources, where only emission integrated across the whole surface is detected.

The WASP Project and the SuperWASP Cameras

The SuperWASP cameras are wide-field imaging systems at the Observatorio del Roque de los Muchachos on the island of La Palma in the Canary Islands, and at the Sutherland Station of the South African Astronomical Observatory. Each instrument has a field of view of some 482 deg2 with an angular scale of 13.7" pixel-1, and is capable of delivering photometry with accuracy better than 1% for objects having V~7.0-11.5. Lower quality data for objects brighter than V~15.0 are stored in the project archive. The systems, while designed to monitor fields with high cadence, are capable of surveying the entire visible sky every 40 minutes. Depending on the observational strategy, the data rate can be up to 100 Gbytes per night. We have produced a robust, largely automatic reduction pipeline and advanced archive, which are used to serve the data products to the consortium members. The main science aim of these systems is to search for bright transiting exoplanet systems suitable for spectroscopic follow-up observations. The first 6 month season of SuperWASP-North observations produced light curves of ~6.7 million objects with 12.9 billion data points.

Fully differential cross sections for transfer ionization - a sensitive probe of high level correlation effects in atoms

The transfer ionization process offers a unique opportunity to study radial and angular electron correlations in the helium atom. We report calculations for the multiple differential cross sections of the transfer ionization process p + He --> H + He++ + e(-). The results of these calculations demonstrate the strong sensitivity of the fully differential cross sections to fine details of electron correlation in the target atom. Specifically, angular electron correlation in the ground state of helium results in a broad peak in the electron emission spectra in the backward direction, relative to the incoming beam. Our model explains some of the key effects observed in measurements of multiple differential cross sections using the COLTRIMS technique.

Transfer ionization process p+He -> H-0+He2++e(-) with the ejected electron detected in the plane perpendicular to the incident beam direction

A joint experimental and theoretical study of the transfer ionization process p+He&RARR; H-0+He2++e(-) is presented for 630-keV proton impact energy, where the electron is detected in a plane perpendicular to the proton beam direction. With this choice of kinematics we find the triple-differential cross section to be particularly sensitive to angular correlation in the helium target. There is a good agreement between the experimental data and theoretical calculations.