Transformation of microporous titanium glycolate nanorods into mesoporous anatase titania nanorods by hot water treatment

High surface area titanium glycolate microporous multi-faceted nanorods were synthesized from the reaction of titanium alkoxides (Ti(OEt)₄, Ti(O ⁱ Pr)₄, or Ti(O ⁿ Bu)₄) with ethylene glycol, using a sol–gel reflux method. The specific surface area of the as-synthesized titanium glycolate nanorods obtained from Ti(OEt)₄ is ~480 m²/g. A hot water treatment at 90 °C for 1 h transformed the titanium glycolate microporous nanorods into mesoporous anatase TiO₂ nanorods. The shape of the nanorods was conserved after hot water treatment and the microporous to mesoporous transformation took place without significant change in the surface area (477 m²/g). Micro Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, solid state NMR, and nitrogen adsorption/desorption were used to characterize the samples. As a demonstration of potential applications, the thus formed mesoporous anatase TiO₂ nanorods were tested for their photocatalytic efficiency in the degradation of crystal violet, and a photodegradation mechanism is proposed.     

Correction to Beaulieu and Sylvie Normandeau (2011).

Reports an error in Prédicteurs des pratiques parentales: Cognitions sociales parentales et comportement des enfants TDAH by Marie-Christine Beaulieu and Sylvie Normandeau (Canadian Journal of Behavioural Science/Revue canadienne des sciences du comportement, Advanced Online Publication, Jul 25, 2011, np). There was an error in the English abstract. This error is corrected in the correction. (The following abstract of the original article appeared in record 2011-15455-001.) The purpose of this study was to examine the association between parental social cognitions (parental causal attributions, parental self-efficacy) and the behavioural characteristics of their child (ADHD subtypes, comorbidity, oppositional and anxiety/shy symptoms). Participants were 110 families with a child with ADHD (ADHD-I : n = 31, ADHD-H : n = 11, ADHD-C : n = 68). Multiple regressions show that parental self-efficacy is associated with more use of appropriate discipline, praise and incentives, positive verbal discipline, and less use of harsh and inconsistent discipline and physical punishment. Results also show that parental causal attributions for the child's misbehaviour to their own efforts are a predictor of positive verbal discipline whereas parents' causal attributions for the child's misbehaviour to the child's lack of efforts are a predictor of harsh and inconsistent discipline. Parents' perception of their child's oppositional symptom is a predictor of appropriate discipline and positive verbal discipline. Finally, children's comorbidity is a predictor of harsh and inconsistent discipline. The findings of this study highlight the importance of parental self-efficacy, because from all the variables studied, it shows the strongest association with positive and negative parenting practices. No association between ADHD subtype and parenting practices were observed. Implications of these results are explored in the discussion. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Green projects: An information drives analysis of four cases

An analysis of four transportation systems (Vélib, Zipcar, ERP Singapore, and Transantiago) shows the strategic value of creating a symbiotic relationship between physical and informational systems in order to increase the convenience and patronage of these systems. The four information drives (ubiquity, uniqueness, unison, and universality) are extended to a physical setting and used to report the key characteristics of each system from both a physical and informational perspective. The article argues that the traditional customer orientation to determining systems requirements may fail to create the breakthrough systems designs that are required to reduce society’s climate harming emissions. Rather, we need an innovation orientation based on understanding consumers’ fundamental physical and informational needs.     

Bandwidth-efficient linear Modulations for multiple-antenna transmission

Some M/spl times/T modulation matrices for M transmit antennas and T symbol periods, with M=2,3,4 and T=2, and M=T=4 are studied. A transmission rate of M symbols per channel use and a transmit diversity order of min(M,T) are achieved over a quasi-static fading channel when using rotated versions of a multidimensional quadratic amplitude modulation with spectral efficiency 2 bits/symbol. Extension to input constellations with higher spectral efficiencies is then considered. The modulations are then generalized to any number of transmit antennas M and any number of symbol periods T, such that a transmission rate of M symbols per channel use, and a transmit diversity of T are achieved under fast fading (ergodic scenario). By means of signal space diversity, the proposed modulations exploit the degrees of freedom of multiantenna channels and have moderate detection complexity at moderate and large signal-to-noise ratios (SNRs).     

A Noise Reduction Amplify-and-Forward Relay Protocol for Distributed Spatial Diversity

Amplify-and-forward transmission has been shown to be a viable transmission protocol for wireless networks incorporating distributed spatial diversity. A drawback of this relatively simple transmission protocol is identified. In addition to signal amplification, perpendicular noise at the relay is also amplified. A method to reduce the noise at the relay prior to amplification is proposed. To demonstrate the improvement of this protocol, we consider single-user single-relay transmission and show that by eliminating perpendicular noise at the relay, the outage region boundaries are reduced. Perpendicular noise elimination is inherent in decode-and-forward relaying. Hence, Fair comparisons of amplify-and-forward relaying with decode-and-forward relaying are based on noise reduced amplify-and-forward relaying     

Infinite series representations of the bivariate Rayleigh andNakagami-m distributions

Despite the usefulness of the bivariate (correlated) Nakagami-m cumulative distribution function (cdf) in communications systems analysis, an infinite series for the computation of this function is not known. In this letter, an infinite series representation of the bivariate cdf is derived. Bounds on the error resulting from truncation of the infinite series are also derived     

A utility perspective on under-excitation limiters

This paper presents a brief review of Ontario Hydro's perspective and experience with power system under excitation limiters (UELs). The purpose of the UEL is reviewed along with the results of field testing and modelling. It is concluded that users of these devices must define the dynamic performance requirements of the limiters, by examining the purpose of their installation, and then setting and testing them accordingly     

Primary infection by type 1 human immunodeficiency virus: diagnosis and prognosis

Primary infection by type 1 human immunodeficiency virus (HIV) is symptomatic in about 70% of cases. The acute illness is a mononucleosis-like syndrome with characteristics such as mucosal ulcerations. The duration and severity of the symptoms appear to be related to the prognosis. After reviewing the most frequent signs and symptoms of primary HIV infection, we report different prognostic studies which examined the association between the acute illness and the progression of HIV disease.     

Maximum-likelihood based estimation of the Nakagami m parameter

Maximum-likelihood estimation of the Nakagami (1960) m parameter is considered. Two new estimators are proposed and examined. The sample mean and the sample variance of the new estimators are compared with the best reported estimator. The new estimators offer superior performance.