1,124 research outputs found
Afro-Cuban and Latin Jazz Compositions
This thesis examines the challenges in musical compositions in Latin jazz styles. The challenges include writing music with different Afro-Cuban rhythms as well as the use of the clave as a backbeat to the melodic ideas. Also, it explores different harmonic and melodic approaches used in a composition and stylistic ideas reflected in jazz styles. For each piece, the composer makes use of different instrumentations and ensemble types. The methodology was to compose seven original songs for small jazz ensembles, and also to analyze the results. For each composition, the author describes his melodic and harmonic approach and the different rhythmic accompaniments. The result of this work is the creation of songs that provide a practical illustration of the different rhythmic patterns and compositional techniques
Young and very young stars in NGC 3372, the Carina nebula
Results are presented of a large-scale imaging photometric study of the stellar population in the northern part of NGC 3372 with a w avelength co verage from 0.33 to 2.5 µm. All observations were made at Las Campanas Observatory . The sizes of the three stellar clusters, Tr 14, Tr 15 and Tr 16, were determined b y means of star counts. Two-colour and colour-magnitude diagrams are presented and analyzed for eac h individual cluster. The three clusters were found to b e at a similar distance from the Sun, = 2 . 7 kpc, but with very large scatter in both A V and d . suggesting drastic variations in intracluster dust densit y . Dust particle size distribution variations are eviden t resulting in wide variations in extinction law. We determined ages bet ween 3 and 60 million years for Tr 15 and bet ween less than 1 and 6 million years for Tr 14 and Tr 16. The Tr 14 cluster is partially em bedded in a dense molecular cloud that extends to wards the south west reaching its highest densit y some three arcmin from the cluster nucleus. The ric h UV field created b y the Tr14 stars ionizes most of the visible HI I region in its vicinit y and most of the radio HI I region Car I. Deep J H K images of the Car I region reveal the presence of a young, em bedded stellar population that includes several O9–B0 stars and an ultracompact HI I region.Fil: Tapia, M.. Universidad Nacional Autónoma de México; MéxicoFil: Roth, M.. Las Campanas Observatory; ChileFil: Vazquez, Ruben Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica la Plata; ArgentinaFil: Persi, P.. IASFC, CNR; Itali
NGC 4337: an over-looked old cluster in the inner disc of the Milky Way
Galactic open clusters do not survive long in the high density regions of the
inner Galactic disc. Inside the solar ring only 11 open clusters are known with
ages older than one Gyr. We show here, basing on deep, high-quality photometry,
that NGC 4337, contrary to earlier findings, is indeed an old open cluster. The
cluster is located very close to the conspicuous star cluster Trumpler 20, as
well mis-classified in the past, and that has received so much attention in
recent years. NGC 4337 shows a significant clump of He-burning stars which was
not detected previously. Its beautiful color-magnitude diagram is strikingly
similar to the one of the classical old open clusters IC 4651, NGC 752, and NGC
3680, and this suggests similar age and composition. A spectroscopic study is
much needed to confirm our findings. This, in turn, would also allow us to
better define the inner disc radial abundance gradient and its temporal
evolution.To this aim, a list of clump star candidates is provided.Comment: 5 pages, 4 eps figures, in press as MNRAS Lette
The thickening of the thin disk in the third Galactic quadrant
In the third Galactic quadrant (180 < l < 270) of the Milky Way, the Galactic
thin disk exhibits a significant warp ---shown both by gas and young stars---
bending down a few kpc below the formal Galactic plane (b=0). This warp shows
its maximum at 240, in the direction of the Canis Major constellation. In a
series of papers we have traced the detailed structure of this region using
open star clusters, putting particular emphasis on the spiral structure of the
outer disk. We noticed a conspicuous accumulation of young star clusters within
2-3 kpc from the Sun and close to b=0, that we interpreted as the continuation
of the Local (Orion) arm towards the outer disk. While most clusters (and young
stars in their background) follow closely the warp of the disk, our decade-old
survey of the spiral structure of this region led us to identify three
clusters, Haffner~18(1 and 2) and Haffner~19, which remain very close to b=0
and lie at distances (4.5, 8.0, and 6.4 kpc) where most of the material is
already significantly warped. Here we report on a search for clusters that
share the same properties as Haffner~18 and 19, and investigate the possible
reasons for such an unexpected occurrence. We present UBVRI photometry of
5~young clusters, namely NGC~2345, NGC~2374, Trumpler~9, Haffner~20, and
Haffner~21, which also lie close to the formal Galactic plane. With the
exception of Haffner~20, in the background of these clusters we detected young
stars that appear close to b=0, and are located at distances up to 8 kpc from
the Sun, thus deviating significantly from the warp. These populations define a
structure that distributes over almost the entire third Galactic quadrant. We
discuss this structure in the context of a possible thin disk flaring, in full
similarity with the Galactic thick disk.Comment: 53 pages, 12 eps figures, in press in the Astronomical Journa
Spiral structure in the outer galactic disk, I: the third galactic quadrant
We combine optical and radio observations to trace the spiral structure in the third quadrant of the Milky Way. The optical observations consist of a large sample of young open clusters and associations, whereas the radio observations consist of a survey of nearby and distant clouds observed in CO. Both the optical and radio samples are the largest ones thus far presented in the literature. We use this unique material to analyze the behavior of interstellar extinction and to trace the detailed structure of the third Galactic quadrant (TGQ).We find that the outer (Cygnus) grand design spiral arm is traced by stellar and CO components, while the Perseus arm is traced solely by CO and is possibly being disrupted by the crossing of the Local (Orion) arm. The Local arm is traced by CO and young stars toward l ¼ 240 and extends for over 8 kpc along the line of sight reaching the outer arm. Finally, we characterize the Galactic warp and compare the geometries implied by the young stellar and CO components.Fil: Vazquez, Ruben Angel. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: May, Jorge. Universidad de Chile; ChileFil: Carraro, Giovanni. European Southern Observatory; ChileFil: Bronfman, Leonardo. Universidad de Chile; ChileFil: Moitinho, Andre. Universidad de Lisboa; PortugalFil: Baume, Gustavo Luis. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentin
The Historical Development of The Piano in Popular Cuban Music: A History of Musical Nationalism
This research is an attempt to clarify the role of the piano in Cuban music and culture through history. Most of the dissertation is carefully focused on the actual music compositions and seeks to present a survey of the devices, techniques, architecture, and genres found in the vast piano repertoire produced in Cuba. As soon as the piano arrived in Cuba at the end of the eighteenth century it became a favorite musical instrument in society. Since its introduction it has played a significant role in the musical expression of the island and soon after it became a symbol of nationalism. Throughout its history in Cuba, the piano has continued to define the stylistic characteristics of a new and emergent musical culture, and even today the piano remains one of the favorite instruments of the country. The importance of the instrument is reflected in the oeuvre of several piano composers who helped develop authentic Cuban genres.
This study discusses and analyzes the musical traits and character of the most distinguished Cuban pianists and composers, and it examines the significance of the piano pedagogues who played a vital role in providing the groundwork for the foundation of the Cuban piano school. It also explores the origin and characteristics of Cuban musical genres which are found in the work of the early piano composers and performers who defined the music traditions of the island. The origins and characteristics of some of the most recognized musical genres and styles, some of which played an influential role in the music of the Caribbean and the Americas, are examined and considered
Mapeos caóticos unidimensionales aplicados a la generación de ruido
Se muestra que, para ambos puntos de vista, es posible calcular la constante de Feigenbaum, usando las distancias que existen entre los valores del parámetro para los cuales ocurre la bifurcación (de órbitas o de distribuciones). Se muestra que en ambos casos se sigue un patrón similar de comportamiento cuando ocurre una bifurcación. Por otro lado, también usando el Teorema Ergódico y usando la distribución invariante, se determina una expresión que permite calcular el valor que tiene el Exponente de Lyapunov en función del parámetro del mapeo; además, apoyados en el diagrama de bifurcación se determinan las islas de estabilidad que posee el mapeo logístico dentro de la región de comportamiento caótico. A partir del análisis hecho para el mapeo logístico, se presenta un procedimiento que permite diseñar un generador de ruido analógico usando un circuito Translinea! Cuadrático (QT: Quadratic Translinear) con transistores MOS (Metal-Oxide Semiconductor), comúnmente llamado circuito MOS QT, cuya función de transferencia tiene un comportamiento consistente con el mapeo logístico. El proceso de iteración de la función logística para la función de transferencia de este circuito se logra considerando la existencia de un amplificador de ganancia μ retroalimentando la salida hacia la entrada. Se muestra el diseño de un circuito MOS QT de Wiegerink, para el que se simula su comportamiento en tiempo y en frecuencia usando MatLab™ y HSPICE™. Para tal efecto, se usa una generalización del mapeo logístico que permite considerar niveles de corriente adecuados para la implementación real de los circuitos MOS. Finalmente, se muestran los resultados obtenidos del análisis de Monte Carlo hecho para el circuito diseñado considerando variaciones en el voltaje de umbral Vih y en las dimensiones de los transistores que constituyen el circuito.El tema principal de esta tesis es el análisis de mapeos1 caóticos unidimensionales con técnicas de mecánica estadística para su aplicación en generadores de ruido. Se analiza el mapeo logístico usando, en función del parámetro que gobierna el mapeo, el diagrama de bifurcación, el diagrama de trayectorias, el Exponente de Lyapunov y su distribución estadística. También, analizando el comportamiento de las órbitas del mapeo, y usando el Teorema de Ergódico, se determina una expresión para calcular la distribución invariante. En particular, usando el diagrama de bifurcación se describe el fenómeno del doblamiento del periodo desde dos puntos de vista. El primero, que es la forma tradicional, analiza la ruta del orden al caos. Se describe el doblamiento del periodo de las órbitas que produce el mapeo haciendo variar el parámetro de μ = O hasta μ = J-1«,, que de acuerdo al criterio de estabilidad, f-1«, es el punto para el cual el mapeo entra al caos. De esta manera, se enfatiza la posibilidad de generar señales periódicas siempre que el valor del parámetro del mapeo sea tal que μ E (O, J-1«,) y aperiódicas si el valor del parámetro es tal que μ E (J-1«,, 4) . El segundo punto de vista, corresponde a un enfoque muy poco abordado, y considera la ruta del caos al orden. Se describe el doblamiento del periodo, pero ahora ya no es un fenómeno sobre las órbitas del mapeo, sino sobre las distribuciones invariantes de dicho mapeo. Esto se demuestra, haciendo variar, en forma decreciente, el parámetro en el intervalo μ E (J-1«,, 4) y calculando numéricamente la distribución invariante del mapeo para aquellos valores del parámetro en los que se hace la bifurcación de distribuciones
ASteCA: Automated Stellar Cluster Analysis
We present the Automated Stellar Cluster Analysis package (ASteCA), a suit of tools designed to fully automate the standard tests applied on stellar clusters to determine their basic parameters. The set of functions included in the code make use of positional and photometric data to obtain precise and objective values for a given cluster’s center coordinates, radius, luminosity function and integrated color magnitude, as well as characterizing through a statistical estimator its probability of being a true physical cluster rather than a random overdensity of field stars. ASteCA incorporates a Bayesian field star decontamination algorithm capable of assigning membership probabilities using photometric data alone. An isochrone fitting process based on the generation of synthetic clusters from theoretical isochrones and selection of the best fit through a genetic algorithm is also present, which allows ASteCA to provide accurate estimates for a cluster’s metallicity, age, extinction and distance values along with its uncertainties. To validate the code we applied it on a large set of over 400 synthetic MASSCLEAN clusters with varying degrees of field star contamination as well as a smaller set of 20 observed Milky Way open clusters (Berkeley 7, Bochum 11, Czernik 26, Czernik 30, Haffner 11, Haffner 19, NGC 133, NGC 2236, NGC 2264, NGC 2324, NGC 2421, NGC 2627, NGC 6231, NGC 6383, NGC 6705, Ruprecht 1, Tombaugh 1, Trumpler 1, Trumpler 5 and Trumpler 14) studied in the literature. The results show that ASteCA is able to recover cluster parameters with an acceptable precision even for those clusters affected by substantial field star contamination. ASteCA is written in Python and is made available as an open source code which can be downloaded ready to be used from its official site.Fil: Perren, Gabriel Ignacio. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Astrofísica de La Plata; Argentina; ArgentinaFil: Vazquez, Ruben Angel. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Astrofísica de La Plata; Argentina; ArgentinaFil: Piatti, Andres Eduardo. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
UC-339 Cybersecurity Analysis of Password Managers
Our capstone project objective is to analyze the cybersecurity framework of popular password managers. The purpose of this project is to research vulnerabilities of the selected password managers and explore possible exploit opportunities for each of them. We chose to analyze five of the most popular password managers on the market: 1Password, BitWarden, LastPass, Google Chrome, and Firefox. We researched their known vulnerabilities and determined we would focus on Bitwarden’s PIN feature, Google Chrome, and Firefox. Upon further research, we were unable to successfully brute force Bitwarden or its PIN feature. If the PIN is enabled, it can be attempted five times before locking the user out and requiring the full master password to be entered, at which point the PIN feature would need to be enabled again. We then shifted focus to Google Chrome and were able to successfully decrypt the local Login Data file that contains user passwords using a password recovery tool named ChromePass. We attempted to use a similar password recovery tool to decrypt the local passwords file for Firefox, however it was unsuccessful due to the tool being flagged as a threat by Microsoft Defender antivirus. Overall, we would consider our capstone a success, seeing as we were able to exploit Google Chrome
- …