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

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

Bioagent defeat in shock driven gas flow

The problem of planar shock interaction with gas cylinders whose axis of symmetry is parallel to the plane of the shock has been well studied both experimentally and numerically, and in this case, the flow evolution driven by Richtmyer-Meshkov instability is well characterized (although, as this thesis shows, assumptions commonly made about the experimental conditions need to be carefully checked). However, for a similar oblique interaction, with the plane of the shock and the axis of the density interface being non-parallel, presently only numerical results exist. The problem of oblique shock interaction is quite interesting to study experimentally both because of a variety of relevant applications and because it adds large-scale three-dimensionality to the initial conditions. Additionally, there is a considerable interest in the problem of shock interaction with particulates, droplets, and bioagents suspended in gas. Here we describe an experimental arrangement for the studies of planar and oblique shocks and present some preliminary results

Analysis of Brownsville Public Utilities Board Hybrid Wind and Solar Energy Systems: Case Study and Analysis in Brownsville, Texas

Engineers are tasked and responsible for studying and designing environmentally safer forms of electrical generation including wind and solar sources. A national effort to reduce dependency on foreign oil due to economic and environmental impacts is underway and race to full scale implementation of alternate energy sources is eminent. The question looms: Is renewable energy generation for residences feasible from an engineering and economic perspective? Although wind and solar generators are gaining ground on conventional generation methods in different sectors, lack of information with regards to design, implementation, and payback still remain a major roadblock. The objective of this case study is to educate utility customers and students in renewable energy technologies. To achieve this, the case study documents a full scale hybrid system installation to be used as an educational outreach tool for the community. Major features of this study incorporate the design, implementation, cost and overall feasibility rating of wind and solar generators installed in Brownsville, Texas. Some of the deliverables include: site environment information, detailed design specifications, and a graphical user interface computer program

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

Comparative Financial Characteristics of U.S. Farms by Type, 2005

This study presents and analyzes the mean financial characteristics of different types of crop and livestock farms in the U.S. in 2005. The eighteen farm types are: poultry, beef cattle, hogs, dairy, general livestock, general cash grain, wheat, corn, soybean, grain sorghum, rice, tobacco, cotton, peanut, general crop, fruits and tree nuts, vegetables, and nursery and greenhouse. Significant, two-way statistical differences in mean farm income statement and farm balance sheet variables are highlighted. Results provide a general indication of the comparative profitability, liquidity, solvency, and financial efficiency of different types of U. S. crop and livestock farms.Farm type, ARMS data, financial characteristics, financial ratios, 2005, Agricultural Finance, Production Economics, Q12, Q14, D21,