Worry, problem elaboration and suppression of imagery: the role of concreteness

Both lay concept and scientific theory claim that worry may be helpful for defining and analyzing problems. Recent studies, however, indicate that worrisome problem elaborations are less concrete than worry-free problem elaborations. This challenges the problem solving view of worry because abstract problem analyses are unlikely to lead to concrete problem solutions. Instead the findings support the avoidance theory of worry which claims that worry suppresses aversive imagery. Following research findings in the dual-coding framework [Paivio, A. (1971). Imagery and verbal processes. New York: Holt, Rhinehart and Winston; Paivio, A. (1986). Mental representations: a dual coding approach. New York: Oxford University Press.], the present article proposes that reduced concreteness may play a central role in the understanding of worry. First, reduced concreteness can explain how worry reduces imagery. Second, it offers an explanation why worrisome problem analyses are unlikely to arrive at solutions. Third, it provides a key for the understanding of worry maintenance

Forces between Colloidal Particles in Aqueous Solutions Containing Monovalent and Multivalent Ions

The present article provides an overview of the recent progress in the direct force measurements between individual pairs of colloidal particles in aqueous salt solutions. Results obtained by two different techniques are being highlighted, namely with the atomic force microscope (AFM) and optical tweezers. One finds that the classical theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO) represents an accurate description of the force profiles even in the presence of multivalent ions, typically down to distances of few nanometers. However, the corresponding Hamaker constants and diffuse layer potentials must be extracted from the force profiles. At low salt concentrations, double layer forces remain repulsive and may become long ranged. At short distances, additional short range non-DLVO interactions may become important. Such an interaction is particularly relevant in the presence of multivalent counterions.Comment: Submitted on 30th of May 2016 as invited article to Curr. Opinion Colloid Interf. Sci. Edited by W. Ducker and P. Claesson. 15 Pages, 7 Figures 82 reference

Weekly assessment of worry: an adaptation of the Penn State Worry Questionnaire for monitoring changes during treatment

An adaptation of the Penn State Worry Questionnaire (PSWQ) [Meyer, T. J., Miller, M. L., Metzger, R. L. and Borkovec, T. D. (1990). Development and validation of the Penn State Worry Questionnaire. Behaviour Research and Therapy, 28, 487-495.] for weekly assessment of worry was evaluated in a brief treatment study. Cognitive restructuring techniques were taught to 28 nonclinical high-worriers, 14 of whom served as a control group in a lagged waiting-list design. Results showed that the Penn State Worry Questionnaire-Past Week (PSWQ-PW) was highly reliable and substantially valid in the assessment of both (a) weekly status of worry and (b) treatment-related changes in worry: average Cronbach's alpha was 0.91; average convergent correlation with a past-week adaptation of the Worry Domains Questionnaire [Tallis, F., Eysenck, M. W. and Mathews, A. (1992). A questionnaire for the measurement of nonpathological worry. Personality and Individual Differences, 13, 161-168.] was 0.63 and pre-post improvement on PSWQ-PW showed a 0.71 correlation with the Questionnaire of Changes in Experiencing and Behavior [Zielke, M. and Kopf-Mehnert, C. (1978). Veränderungsfragebogen des Erlebens und Verhaltens. Weinheim, Germany: Beltz Test Gesellschaft.]. It is concluded that the PSWQ-PW is a useful instrument for monitoring pathological worry in experimental and applied settings

Ion-ion correlation and charge reversal at titrating solid interfaces

Confronting grand canonical titration Monte Carlo simulations (MC) with recently published titration and charge reversal (CR) experiments on silica surfaces by Dove et al. and van der Heyden it et al, we show that ion-ion correlations quantitatively explain why divalent counterions strongly promote surface charge which, in turn, eventually causes a charge reversal (CR). Titration and CR results from simulations and experiments are in excellent agreement without any fitting parameters. This is the first unambiguous evidence that ion-ion correlations are instrumental in the creation of highly charged surfaces and responsible for their CR. Finally, we show that charge correlations result in "anomalous" charge regulation in strongly coupled conditions in qualitative desagreement with its classical treatment.Comment: 4 pages, 4 figures, submitted to PR

Neural networks in cryptography

Bakalářská práce si klade za cíl představit neuronové sítě a jejich vlastnosti, které lze využít pro tvorbu kryptografických protokolů založených na neuronových sítích. Předkládá konkrétní případy využití neuronových sítí~v kryptografii a vytváří teoretický základ pro praktickou implementaci. V praktické části je rozebrána tvorba neuronové sítě, na jejímž základě je vystaven kryptografický model. Vytvořené modely jsou následně podrobeny testování. V závěru jsou diskutovány výhody a nevýhody možného použití v reálných kryptografických modulech.Bachelor's thesis aims to introduce neural networks and their properties, which can be used for creating cryptographic protocols based on neural networks. It proposed concrete use of neural networks in cryptography and creates a teoretical basis for the practical implementation. In practical section is discusses the creation of neural network on which we based cryptographic model. The constructed models are then subjected to testing. At the close of the thesis we discussed the advantages and disadvantages of possible use in real cryptographic modules.

Design of Generalized Powertrain Model

V této práci je popsán obecný model paralélního hybridního automobilu. Celkový hnací systém je složen z menších sub-systémů popsaných pomocí kvazi-statického modelování. Pro dané cesty je vypočítána potřebná síla pro pohon vozidla po trase. Na základě znalosti požadované síly jsou testovány tři řídící systémy. První je založen na heuristických pravidlech. Druhý je založen na optimalizaci dané funkce jenž představuje výslednou spotřebu nebo množství vytvořenýh emisí. Třetí systém je založen na metodě ECMS.In this work is proposed the generalized powertrain of the parallel hybrid car. The powertrain is composed from the sub-models of the power sources. Each sub-model is described by the quasi-static modeling. For given routes is computed the power demand. Based on the derived power demand, three energy management systems are tested. First system is based on heuristic rules. The second one use more sophisticated control algorithms - the optimization method. Main idea is based on minimum principle, when the control algorithm tries to minimize the cost function (fuel use, emission). The last one is based on the equivalent consumption minimization strategy.

Microscopic Protonation Mechanism of Branched Polyamines: Poly(amidoamine) versus Poly(propyleneimine) Dendrimers*

The protonation mechanisms of the poly(amidoamine) (PAMAM) andpoly(propyleneimine) (PPI) dendrimers are clarified and related to their molecular structure. The overall proton binding isotherms can be interpreted in terms of a site binding model, which involves a limited number of parameters, and can be used to gain detailed insight in both macroscopic and microscopic protonation mechanisms. The protonation of the PAMAM dendrimers is dominated by the chemical environment of the amine sites, and the sites protonate almost independently leading to protonation mechanism with a characteristic intermediate core-shell structure. In the case of PPI, the protonation is dominated by the electrostatic nearest-neighbor repulsions between the protonated sites, and leads to an intermediate »onion-like« structure where all the odd shells are protonated

Microscopic Protonation Mechanism of Branched Polyamines: Poly(amidoamine) versus Poly(propyleneimine) Dendrimers*

The protonation mechanisms of the poly(amidoamine) (PAMAM) andpoly(propyleneimine) (PPI) dendrimers are clarified and related to their molecular structure. The overall proton binding isotherms can be interpreted in terms of a site binding model, which involves a limited number of parameters, and can be used to gain detailed insight in both macroscopic and microscopic protonation mechanisms. The protonation of the PAMAM dendrimers is dominated by the chemical environment of the amine sites, and the sites protonate almost independently leading to protonation mechanism with a characteristic intermediate core-shell structure. In the case of PPI, the protonation is dominated by the electrostatic nearest-neighbor repulsions between the protonated sites, and leads to an intermediate »onion-like« structure where all the odd shells are protonated

Charging and Aggregation of Positively Charged Colloidal Latex Particles in Presence of Multivalent Polycarboxylate Anions

Colloidal stability and charging behavior of amidine latex particles in the presence of multivalent oligomers of acrylic acid was investigated by electrophoresis and light scattering. The data were interpreted quantitatively with the theory of Derjaguin, Landau, Verwey and Overbeek (DLVO) whereby the surface potentials were estimated from electrophoresis. Monomer leads to slow aggregation at low concentrations and to rapid aggregation at high concentrations, as characteristic for simple salts. The oligomers induce a charge reversal of the particles. Close to the isoelectric point (IEP) aggregation is rapid while the suspension becomes stable away from this point. At high oligomer concentrations, the aggregation becomes rapid again. The agreement between DLVO theory and experiment is good close to the IEP. At higher oligomer concentrations, the theory predicts larger stabilities than observed experimentally. While inter-particle forces seem to be well described by DLVO theory near the IEP, additional attractive non-DLVO forces are becoming relevant at higher concentration