86,586 research outputs found
A Unified Framework for Investigating Aperiodic and Periodic Components in the Hearbeat Dynamics Spectrum: a Feasibility Study
No full textHeart Rate Variability (HRV) series is a widely used, non-invasive, and easy-to-acquire time-resolved signal for evaluating autonomic control on cardiovascular activity. Despite the recognition that heartbeat dynamics contains both periodic and aperiodic components, the majority of HRV modeling studies concentrate on only one component. On the one hand, there are models based on self-similarity and 1/f behavior that focus on the aperiodic component; on the other hand, there is the conventional division of the spectral domain into narrow-band oscillations, which considers HRV as a combination of periodic components. Taking inspiration from a recent parametrization of EEG power spectra, here we evaluate the applicability of a unified modeling framework to quantitatively assess heartbeat dynamics spectra as a mixture of aperiodic and periodic components. The proposed model is applied on publicly-available, real HRV series collected during postural changes from 10 healthy subjects. Results show that the proposed modeling effectively characterizes different experimental conditions and may complement HRV standard analysis defined in the frequency domain
Estimation of Dynamical Noise Power in Unknown Systems
No full textNoise can be modeled as a sequence of random variables defined on a probability space that may be added to a given dynamical system , which is a map on a phase space. In the non-trivial case of dynamical noise , where follows a Gaussian distribution and the system output is , without any specific knowledge or assumption about , the quantitative estimation of the noise power is a challenge. Here, we introduce a formal method based on the nonlinear entropy profile to estimate the dynamical noise power without requiring knowledge of the specific function. We tested the correctness of the proposed method using time series generated from Logistic maps and Pomeau-Manneville systems under different conditions. Our results demonstrate that the proposed estimation algorithm can properly discern different noise levels without any a priori information
Synthesis of a chemiluminescent probe useful for the purification of steroid 5α-reductase
No full textSteroid 5α-reductase is a system of two isozymes (5αR-1 and 5αR-2), which is related to several human disease. The synthesis of a chemiluminescent probe (AZA-LU) useful for purification of 5αR is described. AZA-LU has a chemiluminescence detectable up to 10-15 M and is a good inhibitor (IC50 = 0.5 μM) for rat 5αR-1 expressed in transformed Saccharomyces cerevisiae yeast. Incubation of AZA-LU with yeast lysates, followed by SDS-PAGE, led to the detection of two luminescent protein regions with estimated molecular weights of 26 kDa and 21 kDa
Synthesis of a Chemiluminescent Probe Useful for the Purification of Steroid 5alpha-Reductase
No full textVariations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Synthesis of taurine analogues from alkenes
No full text(±)trans 2-Aminocyclohexanesulfonic acid and (±)trans 2-aminocyclo-pentanesulfonic acid were prepared from cyclohexene and cyclopentene respectively by sulfur monochloride addition, followed by oxidation to 2-chlorosulfonic acid and substitution of chlorine
[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
Size distribution of ions and elements in urban and peri-urban areas: evidence of dust resuspension
No full textOn the Time-Invariance Properties of Upper Limb Synergies
No full textIn this paper, we present a novel approach to dynamically describe human upper limb trajectories, addressing the question on whether and to which extent synergistic multi-joint behavior is observed and preserved over time evolution and across subjects. To this goal, we performed experiments to collect human upper limb joint angle trajectories and organized them in a dataset of daily living tasks. We then characterized the upper limb poses at each time frame through a technique that we named repeated-principal component analysis (R-PCA). We found that, although there is no strong evidence on the predominance of one principal component (PC) over the others, the subspace identified by the first three PCs takes into account most of the motion variability. We evaluated the stability of these results over time, showing that during the reaching phase, there is a strong consistency of these findings across participants. In other words, our results suggest that there is a time-invariant low-dimensional approximation of upper limb kinematics, which can be used to define a suitable reduced dimensionality control space for upper limb robotic devices in motion phases
Also By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation
No full textThe desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
- …
