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  Partner: UNT College of Arts and Sciences
 Decade: 2000-2009
 Year: 2009
 Language: English
Young Latinos Use of Mobile Phones: A Cross-Cultural Study

Young Latinos Use of Mobile Phones: A Cross-Cultural Study

Date: 2009
Creator: Albarran, Alan B. & Hutton, Brian
Description: This article is about a study designed to analyze how young people, operationalized in this study as people of Latino descent between the ages of 18-25, are using their mobile phone for various applications and what particular gratifications they derive from using the phone. But this study takes on a much larger dimension, because it involves a cross-cultural strategy. Research partners were recruited in five Latin American countries: Mexico, Colombia, Argentina, Chile and Uruguay, in order to collect data and compare it to other countries and to what is happening in the United States.
Contributing Partner: UNT College of Arts and Sciences
Experimental Quenching of Harmonic Stimuli: Universality of Linear Response Theory

Experimental Quenching of Harmonic Stimuli: Universality of Linear Response Theory

Date: July 15, 2009
Creator: Allegrini, Paolo; Bologna, Mauro; Fronzoni, Leone; Grigolini, Paolo & Silvestri, Ludovico
Description: This article discusses experimental quenching of harmonic stimuli. Abstract: We show that liquid crystals in the weak turbulence electroconvective regime respond to harmonic perturbations with oscillations whose intensity decay with an inverse power law of time. We use the results of this experiment to prove that this effect is the manifestation of a form of linear response theory (LRT) valid in the out-of-equilibrium case, as well as at thermodynamic equilibrium where it reduces to the ordinary LRT. We argue that this theory is a universal property, which is not confined to physical processes such as turbulent or excitable media, and that it holds true in all possible conditions, and for all possible systems, including a complex networks, thereby establishing a bridge between statistical physics and all the fields of research in complexity.
Contributing Partner: UNT College of Arts and Sciences
Spontaneous Brain Activity as a Source of Ideal 1/f Noise

Spontaneous Brain Activity as a Source of Ideal 1/f Noise

Date: December 18, 2009
Creator: Allegrini, Paolo; Menicucci, Danilo; Bedini, Remo; Fronzoni, Leone; Gemignani, Angelo; Grigolini, Paolo et al
Description: In this article, the authors study the electroencephalogram (EEG) of 30 closed-eye subjects with a technique of analysis recently proposed to detect punctual events signaling rapid transitions between different metastable states. After single-EEG-channel event detection, the authors study global properties of events simultaneously occurring among two or more electrodes termed coincidences. The authors convert the coincidences into a diffusion process with three distinct rules that can yield the same μ only in the case where the coincidences are driven by a renewal process. The authors establish that the time interval between two consecutive renewal events driving the coincidences has a waiting-time distribution with inverse power-law index μ≈2 corresponding to ideal 1/f noise. The authors argue that this discovery, shared by all subjects of our study, supports the conviction that 1/f noise is an optimal communication channel for complex networks as in art or language and may therefore be the channel through which the brain influences complex processes and is influenced by them.
Contributing Partner: UNT College of Arts and Sciences
From power law intermittence to macroscopic coherent regime

From power law intermittence to macroscopic coherent regime

Date: June 25, 2009
Creator: Bologna, Mauro; Budini, Adrián A.; Giraldi, Filippo & Grigolini, Paolo
Description: This article offers discussions from power law intermittence to macroscopic coherent regime. Abstract: We address the problem of establishing which is the proper form of quantum master equation generating a survival probability identical to that corresponding to the nonergodic sequence of "light on" and "light off" fluorescence fluctuations in blinking quantum dots. We adopt a theoretical perspective based on the assumption that the abrupt transitions from the light on to light off state are the results of many collisions between system and environment, properly described by the Linkblad equation, and that between two consecutive collisions the system dynamics are frozen. This generates a quantum master equation belonging to the recently proposed class of generalized Lindblad equations, with a time convoluted structure, involving in the specific case of this paper both the unitary and the nonunitary contribution of the Lindlad equation. This is the property that under the low-frequency condition makes the new class of generalized Lindblad equation generates the required survival probability. We make the conjecture that this equation corresponds to the cooperative dynamics of many units that, in isolation, are described by the ordinary Lindblad equation. When the time scale of the unitary term of the Lindblad equation is ...
Contributing Partner: UNT College of Arts and Sciences
Redox Activation of Alkene Ligands in Platinum Complexes with Non-innocent Ligands

Redox Activation of Alkene Ligands in Platinum Complexes with Non-innocent Ligands

Date: December 19, 2009
Creator: Boyer, Julie L.; Cundari, Thomas R., 1964-; DeYonker, Nathan J.; Rauchfuss, Thomas B. & Wilson, Scott R.
Description: This article discusses redox activation of alkene ligands. The reactivity of metal olefin complexes with non-innocent ligands (NILs) was examined. Treatment of PtCl2(diene) with the deprotonated catechol or aminophenol ligands afforded the corresponding Pt(NIL)(diene) complexes. The Pt(ͭBAfPh)(COD), Pt(tBAfPh)(nbd), and Pt(O2C6H2tBu2)(COD) (H2tBAfPh = 2-(2-trifluoromethyl)anilino-4,6-di-tert-butylphenol, H2O2C6H2tBu2 = 3,5-di-tert-butylcatechol) complexes were examined by cyclic voltammetry. Treatment of Pt(tBAfPh)(COD) or Pt(tBAfPh)(ndb) with AgPF6 afforded the imino-semiquinones [Pt(tBAfPh)(COD)] PF6 or [Pt(tBAfPh)(nbd)]PF6 respectively. The [Pt(tBAfPh)(COD)] complex was unreactive toward nucleophiles, whereas the oxidized derivative, [Pt(tBAfPh)(COD)]PF6, rapidly and stereospecifically added alkoxides at the carbon trans to the phenolate. The Pt(tBAfPh)(COD), [Pt(tBAfPh)(COD)]PF6, Pt(tBAfPh)(C8H12OMe), and [Cp2Co][Pt-(tBAfPh)(C8H12OMe)] complexes were characterized crystallographically.
Contributing Partner: UNT College of Arts and Sciences
[Review] Tempting Fate: The Ethics of Dual-Use Research

[Review] Tempting Fate: The Ethics of Dual-Use Research

Date: March 20, 2009
Creator: Briggle, Adam
Description: This review is of the book Tempting Fate: The Ethics of Dual-Use Research by Seumas Miller and Michael J. Selgelid. The dual-use dilemma, which Miller and Selgelid argue arises from the fact that "one and the same piece of scientific research sometimes has the potential to be used for harm as well as for good".
Contributing Partner: UNT College of Arts and Sciences
Non-Markovian Nonstationary Completely Positive Open-Quantum-System Dynamics

Non-Markovian Nonstationary Completely Positive Open-Quantum-System Dynamics

Date: August 4, 2009
Creator: Budini, Adrián A. & Grigolini, Paolo
Description: This article discusses non-Markovian nonstationary completely positive open-quantum-system dynamics. By modeling the interaction of a system with an environment through a renewal approach, the authors demonstrate that completely positive non-Markovian dynamics may develop some unexplored nonstandard statistical properties. The renewal approach is defined by a set of disruptive events, consisting in the action of a completely positive superoperator over the system density matrix. The random time intervals between events are described by an arbitrary waiting-time distribution. The authors show that, in contrast to the Markovian case, if one performs a system preparation (measurement) at an arbitrary time, the subsequent evolution of the density-matrix evolution is modified. The nonstationary character refers to the absence of an asymptotic master equation even when the preparation is performed at arbitrary long times. In spite this property, the authors demonstrate that operator expectation values and operators correlations have the same dynamical structure, establishing the validity of a nonstationary quantum regression hypothesis. The nonstationary property of the dynamics is also analyzed through the response of the system to an external weak perturbation.
Contributing Partner: UNT College of Arts and Sciences
Cobalt-Dinitrogen Complexes with Weakened N-N Bonds

Cobalt-Dinitrogen Complexes with Weakened N-N Bonds

Date: June 19, 2009
Creator: Ding, Keying; Pierpont, Aaron W.; Brennessel, William W.; Lukat-Rodgers, Gudrun; Rodgers, Kenton R.; Cundari, Thomas R., 1964- et al
Description: This article discusses research on cobalt-dinitrogen complexes with weakened N-N bonds. Abstracts: Reported N₂ complexes of cobalt do not have substantial weakening of the N-N bond. Using diketiminate ligands to enforce three-coordinate geometries, we have synthesized several novel CoNNCo complexes. In formally univalent complexes, cobalt is poorer than iron at weakening the N-N bond, but in formally zerovalent complexes, cobalt and iron give similar N-N weakening. The weakening is due to cobalt-to-N₂ π-backbonding, and potassium cations pull more electron density into N₂. These results show that the low coordination number of a trigonal-planar geometry is impetus enough to make even the electronegative cobalt weaken the N-N bond of N₂.
Contributing Partner: UNT College of Arts and Sciences
The neuroprotective properties of palmitoylethanolamine against oxidative stress in a neuronal cell line

The neuroprotective properties of palmitoylethanolamine against oxidative stress in a neuronal cell line

Date: December 10, 2009
Creator: Duncan, R. Scott; Chapman, Kent D. & Koulen, Peter
Description: This article discusses the neuroprotective properties of palmitoylethanolamine against oxidative stress in a neuronal cell line. Background: N-acylethanolamines (NAEs) are lipids upregulated in response to cell and tissue injury and are involved in cytoprotection. Arachidonylethanolamide (AEA) is a well characterized NAE that is an endogenous ligand at cannabinoid and vanilloid receptors, but it exists in small quantities relative to other NAE types. The abundance of other NAE species, such as palmitoylethanolamine (PEA), together with their largely unknown function and receptors, has prompted us to examine the neuroprotective properties and mechanism of action of PEA. The authors hypothesized that PEA protects HT22 cells from oxidative stress and activates neuroprotective kinase signaling pathways. Results: Indeed PEA protected HT22 cells from oxidative stress in part by mediating an increase in phosphorylated Akt (pAkt) and ERK 1/2 immunoreactivity as well as pAkt nuclear translocation. These changes take place within a time frame consistent with neuroprotection. Furthermore, the authors determined that changes in pAkt immunoreactivity elicited by PEA were not mediated by activation of cannabinoid receptor type 2 (CB2), thus indicating a novel mechanism of action. These results establish a role for PEA as a neuroprotectant against oxidative stress, which occurs in a variety of ...
Contributing Partner: UNT College of Arts and Sciences
RICHEST - a web server for richness estimation in biological data

RICHEST - a web server for richness estimation in biological data

Date: February 27, 2009
Creator: Durden, Chris & Dong, Qunfeng
Description: This article discusses RICHEST, a web server for richness estimation in biological data. Richness is defined as the number of distinct species or classes in a sample or population. Although richness estimation is an important practice, it requires mathematical and computational methods that are challenging to understand and implement. The authors have developed a web server, RICHness ESTimator (RICHEST), which implements three non-parametric statistical methods for richness estimation. Its user-friendly web interface allows users to analyze and compare their data conveniently over the web.
Contributing Partner: UNT College of Arts and Sciences
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