Detection of time reversibility in time series by ordinal patterns analysis

Time irreversibility is a common signature of nonlinear processes, and a fundamental property of non-equilibrium systems driven by non-conservative forces. A time series is said to be reversible if its statistical properties are invariant regardless of the direction of time. Here we propose the Time Reversibility from Ordinal Patterns method (TiROP) to assess time-reversibility from an observed finite time series. TiROP captures the information of scalar observations in time forward, as well as its time-reversed counterpart by means of ordinal patterns. The method compares both underlying information contents by quantifying its (dis)-similarity via Jensen-Shannon divergence. The statistic is contrasted with a population of divergences coming from a set of surrogates to unveil the temporal nature and its involved time scales. We tested TiROP in different synthetic and real, linear and non linear time series, juxtaposed with results from the classical Ramsey's time reversibility test. Our results depict a novel, fast-computation, and fully data-driven methodology to assess time-reversibility at different time scales with no further assumptions over data. This approach adds new insights about the current non-linear analysis techniques, and also could shed light on determining new physiological biomarkers of high reliability and computational efficiency.Comment: 8 pages, 5 figures, 1 tabl

A critical appraisal of ATLAS9 and NextGen 5 model atmospheres

The fitting atmosphere parameters (Teff, g, and [Fe/H]) for over 300 stars in the Gunn & Striker and Jacoby et al. catalogs have been obtained relying on the Kurucz (1992) ATLAS9 and Hauschildt et al (1999) NextGen5 synthesis models. The output results are compared, and a critical appraisal of both theoretical codes is performed.Comment: 2 pages, 2 figures; proceedings of "New Quests in Stellar Astrophysics: The link between Stars and Cosmology", 26-30 March, 2001, Puerto Vallarta, Mexico, eds. M. Chavez, A. Bressan, A. Buzzoni & D. Mayya, to be published by the Kluwer Academic Publisher

Optical BVRI Photometry of Common Proper Motion F/G/K+M Wide Separation Binaries

We present optical (BVRI) photometric measurements of a sample of 76 common proper motion wide separation main sequence binary pairs. The pairs are composed of a F-, G-, or K-type primary star and an M-type secondary. The sample is selected from the revised NLTT catalog and the LSPM catalog. The photometry is generally precise to 0.03 mag in all bands. We separate our sample into two groups, dwarf candidates and subdwarf candidates, using the reduced proper motion (RPM) diagram constructed with our improved photometry. The M subdwarf candidates in general have larger $V-R$ colors than the M dwarf candidates at a given $V-I$ color. This is consistent with an average metallicity difference between the two groups, as predicted by the PHOENIX/BT-Settl models. The improved photometry will be used as input into a technique to determine the metallicities of the M-type stars.Comment: 26 pages, 8 figures, accepted for publication in A

Optimizing Outreach and Application Assistance Services in Community-based Organizations: Evaluation Findings from The Colorado Trust's Outreach and Enrollment for Children and Youth Grant Strategy

This report discusses findings from the evaluation of The Colorado Trust's three-year, $3.3 million grant strategy (2009-2011) to help expand enrollment of children and youth in public health insurance programs in Colorado. These findings focus on how 12 community-based organizations, with little previous experience in providing application assistance to families to enroll children and youth in public health insurance, offered targeted outreach and application assistance services. These findings provide new insights into the time, effort and outcomes associated with implementing outreach and application assistance services, reinforcing and expanding upon previous literature demonstrating the promise and potential pitfalls of this approach

Music Therapy: Effects on Children\u27s Academic Work and On Task Performance

This study observed the academic engaged time of seven students in a self contained classroom. The service that this study concentrated on was music therapy. The study attempted to answer the following question Does music therapy affect the academic achievement of children with disabilities by improving their on-task behaviors in the classroom? Undercoffer (1997) states that music can enhance student motivation, increase attendance and improve social skills. Data collection was done specifically through the use of an observational instrument, using a five point Likert scale. The instrument measured on-task performance before and after the already scheduled music therapy sessions for three weeks. As a whole group, no significant differences were found among total on-task behaviors prior to or after music therapy. Two themes emerged from the written comments of the Likert scale the first was the focus of the adult on the negative behaviors of the child. The second was teacher cuing, reminders or redirecting verbally of the child. The results of this study were extremely close to displaying significant differences among total on-task behavior prior to or after music therapy. Several students showed improvement on the post music therapy session by a difference of at least five points on their post observational scores