The miscibility and hydrogen bonding interaction of polynorbornene (PNB)/poly(styrene‐co‐hydroxystyrene) (PST‐HST) binary blends were investigated by differential scanning calorimetry and Fourier transform infrared (FT‐IR) spectroscopy. PNB was found to be miscible with PST‐HSTs containing HST unit compositions of 5, 10, 20, and 28 mol‐%, showing a single glass transition, whereas it was immiscible with polystyrene, exhibiting two glass transitions. The hydrogen bonding interaction between the hydroxyl group of PST‐HST and the carbonyl group of PNB was revealed by FT‐IR spectroscopy and plays a key role in the miscibility of PNB/PST‐HST blends.
W e report a case of dysgraphic perform ance in w hich w e have docum ented the selective preservation of suffi x spelling in the context of the phonologically plausible spelling of w ord stem s (e.g. surfed spelled as sourphed, and not as sourpht). T he preservation of suffi x spelling is observed consistently in spite of the fact that the spelling for the suffi x corresponds to m ore than one phonological form. W e argue that the interpretation of such an error pattern requires that w e assum e that the stem m aterial is processed via phonology-to-orthography conversion, w hereas the suffi x m aterial is processed lexically. W e conclude that the results are incom patible w ith an exclusively w hole-w ord view of lexical representation and processing and requires, instead, that w e assum e a lexical orthographic system in w hich m orphologically com plex form s are represented in a com positional m anner. 相似文献
Problem-Solving Therapy (PST) is a cognitive-behavioral intervention that focuses on training in adaptive problem-solving attitudes and skills. The purpose of this paper was to conduct a meta-analysis of controlled outcome studies on efficacy of PST for reducing depressive symptomatology. Based on results involving 21 independent samples, PST was found to be equally effective as other psychosocial therapies and medication treatments and significantly more effective than no treatment and support/attention control groups. Moreover, component analyses indicated that PST is more effective when the treatment program includes (a) training in a positive problem orientation (vs. problem-solving skills only), (b) training in all four major problem-solving skills (i.e., problem definition and formulation, generation of alternatives, decision making, and solution implementation and verification), and (c) training in the complete PST package (problem orientation plus the four problem-solving skills). 相似文献
The purpose of the present study was to provide validation and accuracy data for the pupillographic sleepiness test (PST), on the one hand, by applying self and observer ratings and, on the other hand, by fusioned self and observer ratings as a sleepiness reference value.
Methods
A total of 30?healthy women and men participated in a partial sleep deprivation study (20.00?C04.00?h) and PST measurements were conducted every 2?h for a total of 113?PST measurements. Karolinska Sleepiness Scale (KSS)-based self-reports and five video-based observer ratings of drowsiness (ORD) were measured immediately before the PST in order to provide reliable reference sleepiness values.
Results
PST parameters (pupil unrest index, power of frequency) correlated significantly with the sleepiness validation criteria the KSS and ORD used in this study. Fusioned reference values obtained from one self-report and observer ratings showed a correlation of r?=?0.54, a mean absolute percentage error of 1.58 KSS points, and an error of 35%.
Conclusion
Our results indicate the moderate validity of the PST. Furthermore, the proposed sleepiness reference value might serve as a feasible intermediate solution to estimate sleepiness in the sense of a reference (??quasi-ground truth??) value. This might be true especially for within-subject designs with a focus on the time course of sleepiness. Moreover, the results might show the necessity to recalculate the thresholds of the current PST categories of sleepiness severity. 相似文献
Poly(4‐vinylbenzyl thiocyanate) (PVBT) and a copolymer of styrene and 4‐vinylbenzyl thiocyanate (PST‐co‐VBT) were investigated with regard to changes of the refractive index under UV irradiation (λ = 254 nm). After irradiation, the refractive index nD of PVBT films increased from 1.629 to 1.660. In the case of the copolymer PST‐co‐VBT, nD increased from 1.616 to 1.630. The change of the refractive index mainly resulted from the photoinduced isomerization of thiocyanate groups (SCN) to the corresponding isothiocyanates (NCS). The NCS groups formed in the irradiated zones were selectively modified with gaseous amines (ammonia, propylamine, ethylenediamine, and hydrazine) to give thiourea derivatives via an addition reaction. The gas phase modification induced further changes of the refractive index without any loss of the film quality (e. g. propylamine, Δn up to –0.026, and hydrazine, Δn up to +0.035). In addition, the thickness h of the polymer films increased by up to 21% as a result of the gas phase modification. In contrast, wet chemical treatment with bulky amines (1‐methylnaphthylamine, 1‐pyrenemethylamine) caused a considerable deterioration of the film quality. The variation of the refractive index in polymers such as PVBT and PST‐co‐VBT is of potential interest for holographic recordings and the setup of polymer based DFB lasers. 相似文献