Forced oscillations in an exothermic chemical reaction

We study non-linear behaviour in a model chemical reaction scheme (proposed by Sal?nikov), in which a single chemical species undergoes a two-stage, first-order decay process. The second stage is exothermic and has a temperature-dependent rate, and as a result, spontaneous oscillations in the temperature and the concentration of an intermediate chemical are known to be possible. An additional oscillation is imposed on the system by varying the ambient temperature in a sinusoidal manner. Primary resonance occurs when the forcing frequency coincides with the frequency of the natural oscillations in this scheme and an infinite sequence of super-and subharmonic resonances is also present. Chaos is possible for appropriate parameter values and may result either from the Feigenbaum period-doubling cascade, or else as a result of the Ruelle-Takens approach through quasi-periodicity.     

Brainstem auditory evoked responses in patients with tinnitus

Brainstem auditory evoked responses of 355 patients with uni- or bilateral tinnitus were recorded in order to evaluate the effect of tinnitus on the central auditory system. The amplitudes of waves I, III and V and the latencies of each wave and interpeak latencies were compared to those of a group of 129 controls with normal hearing. The study of the control group initially identified a certain number of concurrent parameters. The brainstem evoked responses of men and women evolved differently from the age of 30 years, latencies of I-III and I-V in men lengthening with age and those of women tending to shorten. The patient groups were therefore compared to a control group of the same sex ratio or of the same sex, half being between 30 and 56 years of age. The tinnitus patients were divided into three groups according to the side affected by tinnitus. Latencies and amplitudes in these groups differed significantly from those of the control group. In order to eliminate hearing loss, the most difficult concurrent factor and almost always associated with tinnitus, the results of individuals with symmetrical hearing loss were compared to those of the control group. Tinnitus was always associated with significant lengthening of 0-I and I-V latencies on the tinnitus-affected side, with a significant reduction in amplitudes of waves I and III, and sometimes of wave V, particularly in the group with left-sided tinnitus. Comparison of tinnitus patients with symmetrical and asymmetrical hearing by sex showed that tinnitus patients of all groups had lengthening of right and left 0-I latencies, apart from the women in the group with right-sided tinnitus, and significant reduction in amplitudes of waves I and III in women and of left III only in men. When hearing loss was asymmetrical and on the tinnitus-affected side, there was also lengthening of 0-I latencies on the tinnitus-affected side in both sexes and of ipsi- and contralateral I-V latencies in women. Right- and left-sided tinnitus was associated with additional differences between the three groups. Correlation coefficient study confirmed that 0-I, I- III and I-V latencies were independent of the mean degree of deafness, deafness at high frequencies and at frequencies around the tinnitus, up to a threshold of hearing loss of 40 dB, above which 0-I and 0-V lengthened in addition to tinnitus. On the other hand, whatever the frequency, tinnitus involved significant lengthening of wave I latencies and modification of the previously recorded amplitudes. Two groups of tinnitus patients could be distinguished: the first, with symmetrical hearing loss, with symmetrical normal latencies, apart from 0-I latencies and the amplitude of the wave on the tinnitus side, and the second with hearing loss predominant on the tinnitus-affected side, with different latencies on each side, 0-I being shorter on the unaffected side, I-III and I-V being lengthened on the unaffected side and 0-I being lengthened on the tinnitus-affected side. Moreover, as disturbances of brainstem evoked responses caused by tinnitus particularly affected waves I and III, the hypothesis of possible involvement of the efferent systems could be proposed.     

Determination of total non-sulphonated aromatic amines in soft drinks and hard candies by reduction and derivatization followed by high-performance liquid chromatography.

Utilizing elements of methodology developed previously for food colours, total free and bound non-sulphonated aromatic amines (NSAA) were determined in commercial samples of soft drink beverages and hard candies. Bound amines in the samples were reduced using sodium dithionite, then total NSAA were extracted into chlorofom, transferred to aqueous acid solution and diazotized with sodium nitrite before coupling with 2-naphthol-3,6-disulphonic acid, disodium salt (R-salt). The coloured derivatives were analysed using reversed-phase ion pair high-performance liquid chromatography (HPLC) and an absorbance detector set at 512 nm. Solid phase extraction cartridges were utilized for extraction and clean-up of the food colours present in the sample, and the concentration of each dye was determined quantitatively using HPLC and absorbance detector wavelengths of 426, 516 or 625 nm. Levels of total NSAA were compatible with those observed previously in food colours. Commercial soft drinks were found to contain (expressed in terms of total free plus bound NSAA in the beverage) 0.19-12.6 ng/ml of aniline, 0.83-8.25 ng/ml 1-naphthylamine and 0.62-1.12 ng/ml 2-naphthylamine. Levels of 0.66-9.15 ng/g of aniline and 2.48-10.6 ng/g 1-naphthylamine were found in commercial samples of hard candies. Bound NSAA in hard candies appeared to survive the manufacturing process. Recoveries averaged 96.9% for tartrazine and 89.6-97.2% for the bound amines when hard candies were prepared in the laboratory.     

Early childhood education for at-risk four-year-olds? Yes.

Extends E. F. Zigler's (see record 1987-23352-001) discussion of early childhood education, concluding, contrary to Zigler, that early childhood education for at-risk children is a positive step in helping them resist the harmful effects of poverty. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Life stress and adjustment: Effects of life events experienced by young adolescents and their parents.

A longitudinal design was used to test the effects of life events experienced by young adolescents and their parents. The criteria were the adolescents' depression, anxiety, and self-esteem. The longitudinal analysis revealed a significant effect for the adolescents' controllable, but not uncontrollable, negative events. However, causal analyses revealed that this effect was the result of the significant relation between initial adjustment and the subsequent occurrence of controllable life stress (e.g., school suspension). The longitudinal analysis also revealed the stress-protective role of positive events, but only with respect to girls' self-esteem. There was no longitudinal support for the role of the parents' negative life events. These findings do not support the etiological importance of an accumulation of relatively discrete negative events experienced by early adolescents and their parents, but they do suggest the need (a) to conceptualize (controllable) life stress as a dependent variable in future research on developmental psychopathology; (b) to examine gender differences in early adolescent life stress; and (c) to develop more sophisticated measures of family life stress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aspects of social and emotional competence in adult attention-deficit/hyperactivity disorder.

Social and emotional competence were evaluated using self-report and behavioral measures in adults with attention-deficit/hyperactivity disorder (ADHD) and controls. Adults with ADHD viewed themselves as less socially competent but more sensitive toward violations of social norms than controls. Films depicting emotional interactions were used to assess linguistic properties of free recall and perceived emotional intensity. Although adults with ADHD used more words to describe the scenes, they used fewer emotion-related words, despite rating the emotions depicted as more intense than did controls. In contrast, no group differences for words depicting social or cognitive processes were observed. Overall, adults with ADHD appear more aware of their problems in social versus emotional skills. Findings may have implications for improving the psychosocial functioning of these adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Insiders Behaving Badly

This column goes beyond previous insider analyses to identify a framework for a taxonomy of insider threats including both malicious and inadvertent actions by insiders that put organizations or their resources at some risk. The framework includes factors reflecting the organization, the individual, the information technology system, and the environment.     

Lexical Influences in Audiovisual Speech Perception.

Phoneme identification with audiovisually discrepant stimuli is influenced hy information in the visual signal (the McGurk effect). Additionally, lexical status affects identification of auditorily presented phonemes. The present study tested for lexical influences on the McGurk effect. Participants identified phonemes in audiovisually discrepant stimuli in which lexical status of the auditory component and of a visually influenced percept was independently varied. Visually influenced (McGurk) responses were more frequent when they formed a word and when the auditory signal was a nonword (Experiment 1). Lexical effects were larger for slow than for fast responses (Experiment 2), as with auditory speech, and were replicated with stimuli matched on physical properties (Experiment 3). These results are consistent with models in which lexical processing of speech is modality independent. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

用于部件检验的快速声学方法——一种测量外购部件内的关键材料性能的新技术。

传统上．声学显微镜用于寻找组件中的分层等内部缺陷。现在．它们被用作快速的材料表征工具来检验外购部件。这类检验是供应链管理的重要内容．对于任何组装公司都非常关键．尤其是无晶圆厂设计公司（fabless）。