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Diagnosis of digestive functional disease by the statistics of continuous monitoring of esophageal acidity

ROGELIO RIVERA LANDA EDUARDO CARDENAS CARDENAS RUBEN YVAN MAARTEN FOSSION MARIO ULISES PEREZ ZEPEDA (2015)

Los avances tecnológicos en los últimos decenios permiten el seguimiento de muchos observables fisiológicos de una manera continua, que en la física se llama una "serie de tiempo". La serie de tiempo fisiológico más estudiada es la del ritmo cardíaco, que puede derivarse de un electrocardiograma (ECG). Los estudios han demostrado que un corazón sano se caracteriza por una serie de tiempo complejo y alta variabilidad de la frecuencia cardíaca (VFC). En condiciones adversas, la serie crónica cardiaca degenera hacia la aleatoriedad (como se ve en, por ejemplo, la fibrilación) o la rigidez (como se ve en, por ejemplo, el envejecimiento), ambos que corresponden a una pérdida de HRV tal como se describe por, por ejemplo, Golberger et. Al [1]. Los ritmos cardíaco y digestivo son regulados por el sistema nervioso autónomo (ANS), que consiste en dos ramas antagónicas, la rama ortosimpática (ONS) que acelera el ritmo cardiaco, pero desacelera el sistema digestivo, y la marca parassimpática (SNP) sentido contrario. Debido a esta razón, se podría esperar que las estadísticas de las series de tiempo gastro-esofágico, como describe Gardner et al. Alabama. [2, 3], refleja el estado de salud del sistema digestivo de manera similar a la VFC en el caso cardíaco, descrito por Minocha et al. Alabama. En el presente proyecto, aplicamos métodos estadísticos derivados del análisis de HRV a series temporales de acidez esofágica (pHmetría 24h). El estudio se realiza a partir de datos de una gran población de pacientes del Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán. Nuestro enfoque está en los pacientes con enfermedad funcional (síntomas pero sin daño anatómico). Encontramos que los enfoques estadísticos tradicionales (por ejemplo, el análisis espectral de Fourier) son incapaces de distinguir entre diferentes degeneraciones del sistema digestivo, como la enfermedad de reflujo gástrico esofágico (ERGE) o trastorno gastrointestinal funcional (FGID).

Article

CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA Física Física teórica Enfermedades del sistema digestivo (diagnóstico) Enfermedades gastrointestinales Enfermedades esofágicas Enfermedades del corazón (diagnóstico) Control de la frecuencia cardiaca Electrocardiografía Physics Digestive system disease (diagnosis) Gastrointestinal disease Esophageal disease Heart disease (diagnosis) Heart rate monitoring Electrocardiography

Diagnosis of digestive functional disease by the statistics of continuous monitoring of esophageal acidity

ROGELIO RIVERA LANDA EDUARDO CARDENAS CARDENAS RUBEN YVAN MAARTEN FOSSION MARIO ULISES PEREZ ZEPEDA (2015)

Los avances tecnológicos en los últimos decenios permiten el seguimiento de muchos observables fisiológicos de una manera continua, que en la física se llama una "serie de tiempo". La serie de tiempo fisiológico más estudiada es la del ritmo cardíaco, que puede derivarse de un electrocardiograma (ECG). Los estudios han demostrado que un corazón sano se caracteriza por una serie de tiempo complejo y alta variabilidad de la frecuencia cardíaca (VFC). En condiciones adversas, la serie crónica cardiaca degenera hacia la aleatoriedad (como se ve en, por ejemplo, la fibrilación) o la rigidez (como se ve en, por ejemplo, el envejecimiento), ambos que corresponden a una pérdida de HRV tal como se describe por, por ejemplo, Golberger et. Al [1]. Los ritmos cardíaco y digestivo son regulados por el sistema nervioso autónomo (ANS), que consiste en dos ramas antagónicas, la rama ortosimpática (ONS) que acelera el ritmo cardiaco, pero desacelera el sistema digestivo, y la marca parassimpática (SNP) sentido contrario. Debido a esta razón, se podría esperar que las estadísticas de las series de tiempo gastro-esofágico, como describe Gardner et al. Alabama. [2, 3], refleja el estado de salud del sistema digestivo de manera similar a la VFC en el caso cardíaco, descrito por Minocha et al. Alabama. En el presente proyecto, aplicamos métodos estadísticos derivados del análisis de HRV a series temporales de acidez esofágica (pHmetría 24h). El estudio se realiza a partir de datos de una gran población de pacientes del Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán. Nuestro enfoque está en los pacientes con enfermedad funcional (síntomas pero sin daño anatómico). Encontramos que los enfoques estadísticos tradicionales (por ejemplo, el análisis espectral de Fourier) son incapaces de distinguir entre diferentes degeneraciones del sistema digestivo, como la enfermedad de reflujo gástrico esofágico (ERGE) o trastorno gastrointestinal funcional (FGID).

Article

CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA Física Física teórica Enfermedades del sistema digestivo (diagnóstico) Enfermedades gastrointestinales Enfermedades esofágicas Enfermedades del corazón (diagnóstico) Control de la frecuencia cardiaca Electrocardiografía Physics Digestive system disease (diagnosis) Gastrointestinal disease Esophageal disease Heart disease (diagnosis) Heart rate monitoring Electrocardiography

Portable electronic device to assess the human balance using a minimum number of sensors

ANGEL GABRIEL ESTEVEZ PEDRAZA RIGOBERTO MARTINEZ MENDEZ OTNIEL PORTILLO RODRIGUEZ Jorge Rodriguez Arce LORENA PARRA RODRIGUEZ (2020)

Objective: This paper presents the design and development of a new electronic portable device to assess the human balance of the human body during standing, using a minimal number of sensors and peripheral components. This device is aimed to evaluate human balance in environments outside of specialized laboratories, such as small clinics and therapy offices. Approach: The design is based on previous designs using three or more resistive force sensors attached to the feet, however in the present work, the sensors were attached on an adjustable platform, to fit several sizes of feet. Furthermore, all the signal acquisition, process, storage and display are executed by an embedded electronic system, thus avoiding the use of computers and external peripherals. A new method to compute the CoP using only two sensors per foot was developed and tested in a group of 50 university students, (17 women and 33 men), 26.04 ± 4.94 years. Main results: It was developed a portable electronic system to measure the trajectory of the CoP and to calculate the indexes values derived from it. The system is capable to discriminate between measuring situations (open and closed eyes), using only two sensors per foot (p < 0.0001). A comparison between the values obtained for young subjects using the proposed device, and the values reported in the literature showed a similar tendency. Significance: The results indicate that the proposed system is a good, low-cost, and easy-to-use alternative tool for researchers and clinicians interested in the evaluation of human balance, especially if the measurements must be done outside laboratories.

Article

CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA Física Equilibrio humano Puntos mínimos de detección Centro de trayectoria de presión Tecnología Gerontecnología Physics Human balance Minimun points of sensing Centre of pressure trajectory Technology Gerontechnology

Critical temperatures of real fluids from the extended law of corresponding states

González-Calderón Alfredo JORGE ADRIAN PERERA BURGOS Daniel Porfirio Luis Jiménez (2019)

The extended law of corresponding states was proposed based on the patterns observed in the second virial coefficient for potential models of variable range. In this work, we propose the use of this law, together with a generalized Lennard-Jones (or approximate nonconformal, ANC) potential, to predict the critical temperatures of real fluids. To this end, we first observe that the temperatures obtained from the scaling law are in agreement with those obtained from molecular simulations of ANC fluids. For short ranges, however, validation is performed by mapping the ANC fluid to the square well fluid because no simulation data have been reported for the former fluid for these ranges. Overall, the analysis shows the validity of the scaling law and the ANC potential for predicting critical temperatures for any range. With this in mind, the well depths of the effective binary potentials of atoms and molecules are rescaled to apply a correction for the three-body nonadditive interaction in order to determine the critical temperatures of fluids.

Article

NANOSCIENCE & NANOTECHNOLOGY MATERIALS SCIENCE MULTIDISCIPLINARY PHYSICS APPLIED INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES PROPIEDADES DE LOS MATERIALES PROPIEDADES DE LOS MATERIALES

Data-adaptive unfolding of nuclear excitation spectra: a time-series approach

GAMALIEL TORRES VARGAS RUBEN YVAN MAARTEN FOSSION VICTOR MANUEL VELAZQUEZ AGUILAR JUAN CARLOS LOPEZ VIEYRA (2014)

Abstract: A common problem in the statistical characterization of the excitation spectrum of quantum systems is the adequate separation of global system-dependent properties from the local fluctuations that are universal. In this process, called unfolding, the functional form to describe the global behaviour is often imposed externally on the data and can introduce arbitrarities in the statistical results. In this contribution, we show that a quantum excitation spectrum can readily be interpreted as a time series, before any previous unfolding. An advantage of the time-series approach is that specialized methods such as Singular Spectrum Analysis (SSA) can be used to perform the unfolding procedure in a data-adaptive way. We will show how SSA separates the components that describe the global properties from the components that describe the local fluctuations. The partial variances, associated with the fluctuations, follow a definite power law that distinguishes between soft and rigid excitation spectra. The data-adaptive fluctuation and trend components can be used to reconstruct customary fluctuation measures without ambiguities or artifacts introduced by an arbitrary unfolding, and also define the global level density of the excitation spectrum. The method is applied to nuclear shell-model calculations for 48Ca, using a realistic force and Two-Body Random Ensemble (TBRE) interactions. We show that the statistical results are very robust against a variation in the parameters of the SSA method.

Conclusions: We have proposed a method to realize a data-adaptive unfolding of quantum excitation spectra, which avoids the possible ambiguities when the unfolding functional form is imposed externally to the data (e.g. using a polynomial of arbitrary degree). We interpreted the sequence of actual energy levels {E(i), i = 1 . . . N} as a generalized time series, and used the data-adaptive SSA method to separate in an unambiguous way the global trend E(i) from the local fluctuations Ee(i). This first step corresponds with the detrending part of the unfolding procedure. The statistical results are very robust against a variation in the two parameters of the method (embedding dimension L and number of trend components nT ). The partial variances, associated to the fluctuations, follow a power law that distinguishes between soft and rigid excitation spectra. If desired, the data-adaptive trend components E(i) can be used to calculate the global level density behaviour, and specialized techniques from signal analysis can be applied to the data-adaptive fluctuation components Ee(i) to further specify the fluctuation statistics. Also the rescaling step of the unfolding procedure can be carried out in a self-consistent way, after which traditional fluctuation measures such as the Nearest-Neighbour Spacing (NNS) distribution and ∆3 can be calculated without ambiguities. We tested the present data-adaptive unfolding method for the J π = 4+ excitation subspectrum of the 48Ca atomic nucleus, and our results are in correspondence with previous results in literature. This also illustrates the fact that the fluctuations in the excitation energies Ee(i) (considered in the present contribution) are statistically equivalent to the fluctuations Nf[E(i)] of the integrated density function (IDOS) (considered traditionally). In a forthcoming publication, we will show that the proposed unfolding method is general enough to apply to the excitation spectra of other quantum systems, and also to the eigenspectra of random matrices in various applications in quantum and classical physics [39]. We acknowledge financial support from CONACYT (grants CB-2011-01-167441, CB-2010-01- 155663, I010/266/2011/C-410-11 and grant 351103 from the Red Tem´atica Envejecimiento, Salud y Desarrollo Social), PAPIIT-DGAPA (grant IN114411), the European Commission (project FP7-PEOPLE-2009-IRSES-247541-MATSIQEL) and the Instituto Nacional de Geriatr´ıa (project DI-PI-002/2012). The authors wish to thank Dr. A. Frank and collaborators for fruitful discussions.

Article

CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA Física Física molecular Espectroscopía molecular Disciplinas de ciencias naturales Física nuclear Natural sciences disciplines Physics Nuclear physics Molecular spectroscopy

Quantum interference vs quantum chaos in the nuclear shell model

AARON GERARDO FERNANDEZ ALARCON EDNA MAGDALENA HERNANDEZ GONZALEZ MATHIEU CHRISTIAN ANNE HAUTEFEUILLE EMMANUEL LANDA HERNANDEZ IRVING OMAR MORALES AGISS VICTOR MANUEL VELAZQUEZ AGUILAR RUBEN YVAN MAARTEN FOSSION CARLOS ERNESTO VARGAS MADRAZO ALEJANDRO FRANK HOEFLICH (2015)

Abstract: In this paper we study the complexity of the nuclear states in terms of a two body quadupole-quadrupole interaction. Energy distributions and eigenvectors composition exhibit a visible interference pattern which is dependent on the intensity of the interaction. In analogy with optics, the visibility of the interference is related to the purity of the states, therefore, we show that the fluctuations associated with quantum chaos have as their origin the remaining quantum coherence with a visibility magnitude close to 5%.

Conclusions: In conclusion, we have studied the statistics of energy levels considering the visibility of its distribution as a function of the parameter of quadrupolar interaction. Visibility is an indication of the degree of coherence of nuclear states associated to studied energies. By comparing the visibility to the respective power spectrum, we found a correspondence between the statistics of energy levels and the degree of purity of the nuclear states. The 1/f fluctuations characterizing quantum chaos may be interpreted as a residuum of coherence between nuclear states. The lowest states maintain a high degree of purity, whereas decoherence has almost erased the origin of all intermediate energy states. To define the behavior known as quantum chaos, it is therefore not necessary to manipulate classical or semi-classical images from some dynamic system. Quantum decoherence may be used instead.

Article

CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA Física Física teórica Teoría cuántica de campos Física nuclear Teoría cuántica Physics Nuclear physics Qantum theory

Quantum interference vs quantum chaos in the nuclear shell model

AARON GERARDO FERNANDEZ ALARCON EDNA MAGDALENA HERNANDEZ GONZALEZ MATHIEU CHRISTIAN ANNE HAUTEFEUILLE EMMANUEL LANDA HERNANDEZ IRVING OMAR MORALES AGISS VICTOR MANUEL VELAZQUEZ AGUILAR RUBEN YVAN MAARTEN FOSSION CARLOS ERNESTO VARGAS MADRAZO ALEJANDRO FRANK HOEFLICH (2015)

Abstract: In this paper we study the complexity of the nuclear states in terms of a two body quadupole-quadrupole interaction. Energy distributions and eigenvectors composition exhibit a visible interference pattern which is dependent on the intensity of the interaction. In analogy with optics, the visibility of the interference is related to the purity of the states, therefore, we show that the fluctuations associated with quantum chaos have as their origin the remaining quantum coherence with a visibility magnitude close to 5%.

Conclusions: In conclusion, we have studied the statistics of energy levels considering the visibility of its distribution as a function of the parameter of quadrupolar interaction. Visibility is an indication of the degree of coherence of nuclear states associated to studied energies. By comparing the visibility to the respective power spectrum, we found a correspondence between the statistics of energy levels and the degree of purity of the nuclear states. The 1/f fluctuations characterizing quantum chaos may be interpreted as a residuum of coherence between nuclear states. The lowest states maintain a high degree of purity, whereas decoherence has almost erased the origin of all intermediate energy states. To define the behavior known as quantum chaos, it is therefore not necessary to manipulate classical or semi-classical images from some dynamic system. Quantum decoherence may be used instead.

Article

CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA Física Física teórica Teoría cuántica de campos Física nuclear Teoría cuántica Physics Nuclear physics Qantum theory

Scale invariance, self similarity and critical behavior in classical and quantum systems

IRVING OMAR MORALES AGISS EMMANUEL LANDA HERNANDEZ RUBEN YVAN MAARTEN FOSSION ALEJANDRO FRANK HOEFLICH (2012)

Abstract:

Symmetry and self-affinity or scale invariance are related concepts. We explore the fractal properties of fluctuations in dynamical systems, using some of the available tools in the context of time series analysis. We carry out a power spectrum study in the Fourier domain, the method of detrended fluctuation analysis and the investigation of autocorrelation function behavior. Our study focuses on two particular examples, the logistic module-1 map, which displays properties of classical dynamical systems, and the excitation spectrum of a schematic shell-model Hamiltonian, which is a simple system exhibiting quantum chaos.

Conclusions: Self-similarity is a very important property of dynamical systems which can be analyzed usingthe usual tools of time-series analysis. For the dynamical systems presenting scale invariancethe power spectral density behaves as a power lawP(f)∼1/fβ. The 1/fnoise (β= 1) can beseen as a particular type of self-similar noise. It corresponds to signals that maximize the rangeof their correlations. We suggest in this paper that time series of both classical and quantumdynamical systems that undergo a transition between two regimes, exhibit 1/fbehavior nearthe transitional point. We report in detail on two specific examples: the Module-1 Logistic Mapfor the classical case, and a schematic nuclear shell-model Hamiltonian for the quantum case.We studied the corresponding time series by spectral analysis, and with the DFA method.In the case of the module-1 logistic map, for values of the control parameterk <0, wefound regular time series (with Lyapunov exponentλk<0), for a value ofk= 1, a correlated non-periodic time series (with Lyapunov exponentλk= 0), and for control parametersk >1we observe chaotic time series (with Lyapunov exponentλk>0). We find 1/fbehavior for thecorrelated non-periodic time series at the transitional point, whereas the regular and chaotictime series correspond to 1/fβ(β6= 1) power spectral density. We describe a generic nuclear ex-citation spectrum, using a schematic Hamiltonian. The Hamiltonian has two competing terms:a single-particle term, and a residual quadrupole-quadrupole term. Each term individually isintegrable. A control parameter allows for a smooth transition between the two extreme regimes.Both extreme integrable excitation spectra correspond to 1/f2(brownian) power laws, whereasthe transitional excitation spectrum corresponds with a 1/fpower spectral density. For twospecific systems, we found a generic 1/fbehavior of the corresponding time series, where thelong-range correlations are maximized, exactly at the point where the transition occurs. Weare currently applying these techniques to other systems, such as simple coupled pendula andphoton counting rates in different kinds of emitting light sources [34]. We believe that time se-ries analysis can provide relevant information in both physical and biological systems, includingearly warning signals in diverse phenomena.

Article

CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA Física Física teórica Teoría cuántica de campos Física nuclear Physics Nuclear physics Quantum theory

Lévy Flights, 1/f noise and self organized criticality in a traveling agent model

Oliver López Corona PABLO PADILLA LONGORIA OSCAR ARNOLDO ESCOLERO FUENTES ALEJANDRO FRANK HOEFLICH RUBEN YVAN MAARTEN FOSSION (2013)

Un nuevo análisis de un modelo de agente viajante previamente estudiado, mostró que existe una relación entre el grado de homogeneidad del medio en el que se mueven los agentes, los patrones de movimiento del agente y el ruido generado por sus desplazamientos. Se demostró que, para un valor particular de homogeneidad, el sistema se organiza en un estado en el que los agentes transportan Lévy camina y la señal de desplazamiento corresponde a 1 / f de ruido. Usando argumentos probabilistas, conjeturamos que 1 / f el ruido es una huella dactilar de una fase estadística de transición, de la aleatoriedad (desorden) a la predictibilidad (orden), y que surge de la naturaleza contextual del sistema que la genera.

Article

CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA MEDICINA Y CIENCIAS DE LA SALUD Física Acústica Física de la salud Physics Acoustics Health physics Fenómenos fisiológicos Crecimiento y desarrollo Envejecimiento Physiological phenomena Growth and development Aging

Scale invariance, self similarity and critical behavior in classical and quantum systems

IRVING OMAR MORALES AGISS EMMANUEL LANDA HERNANDEZ RUBEN YVAN MAARTEN FOSSION ALEJANDRO FRANK HOEFLICH (2012)

Abstract:

Symmetry and self-affinity or scale invariance are related concepts. We explore the fractal properties of fluctuations in dynamical systems, using some of the available tools in the context of time series analysis. We carry out a power spectrum study in the Fourier domain, the method of detrended fluctuation analysis and the investigation of autocorrelation function behavior. Our study focuses on two particular examples, the logistic module-1 map, which displays properties of classical dynamical systems, and the excitation spectrum of a schematic shell-model Hamiltonian, which is a simple system exhibiting quantum chaos.

Conclusions: Self-similarity is a very important property of dynamical systems which can be analyzed usingthe usual tools of time-series analysis. For the dynamical systems presenting scale invariancethe power spectral density behaves as a power lawP(f)∼1/fβ. The 1/fnoise (β= 1) can beseen as a particular type of self-similar noise. It corresponds to signals that maximize the rangeof their correlations. We suggest in this paper that time series of both classical and quantumdynamical systems that undergo a transition between two regimes, exhibit 1/fbehavior nearthe transitional point. We report in detail on two specific examples: the Module-1 Logistic Mapfor the classical case, and a schematic nuclear shell-model Hamiltonian for the quantum case.We studied the corresponding time series by spectral analysis, and with the DFA method.In the case of the module-1 logistic map, for values of the control parameterk <0, wefound regular time series (with Lyapunov exponentλk<0), for a value ofk= 1, a correlated non-periodic time series (with Lyapunov exponentλk= 0), and for control parametersk >1we observe chaotic time series (with Lyapunov exponentλk>0). We find 1/fbehavior for thecorrelated non-periodic time series at the transitional point, whereas the regular and chaotictime series correspond to 1/fβ(β6= 1) power spectral density. We describe a generic nuclear ex-citation spectrum, using a schematic Hamiltonian. The Hamiltonian has two competing terms:a single-particle term, and a residual quadrupole-quadrupole term. Each term individually isintegrable. A control parameter allows for a smooth transition between the two extreme regimes.Both extreme integrable excitation spectra correspond to 1/f2(brownian) power laws, whereasthe transitional excitation spectrum corresponds with a 1/fpower spectral density. For twospecific systems, we found a generic 1/fbehavior of the corresponding time series, where thelong-range correlations are maximized, exactly at the point where the transition occurs. Weare currently applying these techniques to other systems, such as simple coupled pendula andphoton counting rates in different kinds of emitting light sources [34]. We believe that time se-ries analysis can provide relevant information in both physical and biological systems, includingearly warning signals in diverse phenomena.

Article

CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA Física Física teórica Teoría cuántica de campos Física nuclear Physics Nuclear physics Quantum theory