Aproximación de señales acústicas a través de funciones polinomiales

Approximation of acoustic signals through polynomial functions

Andrea Cruz Rojas (2023, [Tesis de maestría])

Las señales acústicas presentan diversas características, como la frecuencia, amplitud y duración. Existen varias formas de representar una señal acústica, siendo la representación en el dominio del tiempo la más común. Esta representación permite visualizar la variación de la amplitud a lo largo del tiempo, analizar la duración, la forma de onda y los cambios rápidos o lentos en la amplitud. Sin embargo, las señales acústicas pueden contener un gran número de elementos, lo que resulta en archivos digitales de gran tamaño que dificultan su envío y almacenamiento. En este trabajo, se llevó a cabo un estudio de aproximación de señales acústicas utilizando diversas funciones polinomiales, como las funciones Zernike, Bessel y Jinc para reducir la cantidad de datos necesarios para representar la señal acústica, lo que simplifica la manipulación de dichos datos. El objetivo es identificar qué polinomio y cuántos coeficientes ofrecen un mejor rendimiento, es decir, una mejor señal acústica. Este estudio se basa en una evaluación objetiva y subjetiva de la reconstrucción de las señales acústicas, lo cual, hasta donde tenemos conocimiento, no se ha estudiado utilizando ambas metodologías en conjunto.

Acoustic signals have various characteristics, such as frequency, amplitude and duration. There are several ways to represent an acoustic signal, with time domain representation being the most common. This representation allows you to visualize the variation of the amplitude over time, analyze the duration, the waveform and the fast or slow changes in the amplitude. However, acoustic signals can contain a large number of elements, resulting in large digital files that make them difficult to send and store. In this work, an approximation study of acoustic signals was carried out using various polynomial functions, such as the Zernike, Bessel and Jinc functions to reduce the amount of data necessary to represent the acoustic signal, which simplifies the manipulation of said data. The objective is to identify which polynomial and how many coefficients offer better performance, that is, a better acoustic signal. This study is based on an objective and subjective evaluation of the reconstruction of acoustic signals, which, to the best of our knowledge, has not been studied using both methodologies together.

Calidad de audio, Compresión de señal acústica, Polinomios ortogonales, Pruebas objetivas y subjetivas. Audio quality, Acoustic signal compression, Orthogonal polynomials, Objective and Subjective Tests INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE LAS TELECOMUNICACIONES ELECTROACÚSTICA ELECTROACÚSTICA

Protein retention assessment of four levels of poultry by-product substitution of fishmeal in rainbow trout (Oncorhynchus mykiss) diets using stable isotopes of nitrogen (δ15N) as natural tracers

DANIEL BADILLO ZAPATA (2014, [Artículo])

This is second part from an experiment where the nitrogen retention of poultry by-product meal (PBM) compared to fishmeal (FM) was evaluated using traditional indices. Here a quantitative method using stable isotope ratios of nitrogen (δ15N values) as natural tracers of nitrogen incorporation into fish biomass is assessed. Juvenile rainbow trout (Oncorhynchus mykiss) were fed for 80 days on isotopically distinct diets in which 0, 33, 66 and 100% of FM as main protein source was replaced by PBM. The diets were isonitrogenous, isolipidic and similar in gross energy content. Fish in all treatments reached isotopic equilibrium by the end of the experiment. Two-source isotope mixing models that incorporated the isotopic composition of FM and PBM as well as that of formulated feeds, empirically derived trophic discrimination factors and the isotopic composition of fish that had reached isotopic equilibrium to the diets were used to obtain a quantitative estimate of the retention of each source of nitrogen. Fish fed the diets with 33 and 66% replacement of FM by PBM retained poultry by-product meal roughly in proportion to its level of inclusion in the diets, whereas no differences were detected in the protein efficiency ratio. Coupled with the similar biomass gain of fishes fed the different diets, our results support the inclusion of PBM as replacement for fishmeal in aquaculture feeds. A re-feeding experiment in which all fish were fed a diet of 100% FM for 28 days indicated isotopic turnover occurred very fast, providing further support for the potential of isotopic ratios as tracers of the retention of specific protein sources into fish tissues. Stable isotope analysis is a useful tool for studies that seek to obtain quantitative estimates of the retention of different protein sources. © 2014 Badillo et al.

nitrogen 15, nitrogen, protein intake, animal behavior, animal experiment, animal food, animal tissue, aquaculture, Article, biomass, controlled study, energy metabolism, food composition, juvenile animal, nonhuman, poultry by product meal, protein a CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA

Suppression of breast tumor growth and metastasis by an engineered transcription factor

Adriana Beltran Lopez (2011, [Artículo])

Maspin is a tumor and metastasis suppressor playing an essential role as gatekeeper of tumor progression. It is highly expressed in epithelial cells but is silenced in the onset of metastatic disease by epigenetic mechanisms. Reprogramming of Maspin epigenetic silencing offers a therapeutic potential to lock metastatic progression. Herein we have investigated the ability of the Artificial Transcription Factor 126 (ATF-126) designed to upregulate the Maspin promoter to inhibit tumor progression in pre-established breast tumors in immunodeficient mice. ATF-126 was transduced in the aggressive, mesenchymal-like and triple negative breast cancer line, MDA-MB-231. Induction of ATF expression in vivo by Doxycycline resulted in 50% reduction in tumor growth and totally abolished tumor cell colonization. Genome-wide transcriptional profiles of ATF-induced cells revealed a gene signature that was found over-represented in estrogen receptor positive (ER+) "Normal-like" intrinsic subtype of breast cancer and in poorly aggressive, ER+ luminal A breast cancer cell lines. The comparison transcriptional profiles of ATF-126 and Maspin cDNA defined an overlapping 19-gene signature, comprising novel targets downstream the Maspin signaling cascade. Our data suggest that Maspin up-regulates downstream tumor and metastasis suppressor genes that are silenced in breast cancers, and are normally expressed in the neural system, including CARNS1, SLC8A2 and DACT3. In addition, ATF-126 and Maspin cDNA induction led to the re-activation of tumor suppressive miRNAs also expressed in neural cells, such as miR-1 and miR-34, and to the down-regulation of potential oncogenic miRNAs, such as miR-10b, miR-124, and miR-363. As expected from its over-representation in ER+ tumors, the ATF-126-gene signature predicted favorable prognosis for breast cancer patients. Our results describe for the first time an ATF able to reduce tumor growth and metastatic colonization by epigenetic reactivation of a dormant, normal-like, and more differentiated gene program. © 2011 Beltran et al.

artificial transcription factor 126, complementary DNA, doxycycline, estrogen receptor, maspin, microRNA, retrovirus vector, transcription factor, unclassified drug, estrogen receptor, serine proteinase inhibitor, SERPIN B5, SERPIN-B5, transcription BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) BIOLOGÍA ANIMAL (ZOOLOGÍA)