Stability Of Preferences Research Articles

Synthesis and characterization of high refractive epoxy prepolymers with different molecular structures

Three kinds of epoxy prepolymers with high refractive index, diglycidyl ether of thiodibenzenethiol (DGETDBT), diglycidyl ether of thiobis-phenol (DGETP), and diglycidyl ether of oxydiphenol, were synthesized via a two-step method, and the relationship between the chemical structure and refractive index of epoxy prepolymer was discussed. Their chemical structures were characterized using Fourier transform infrared (FTIR) spectrometer and proton nuclear magnetic resonance spectrometer. The curing behavior of all the epoxy prepolymers cured with methylhexahydrophthalic anhydride (MHHPA) was studied using differential scanning calorimetry and was compared with that of diglycidyl ether of bisphenol A (DGEBA). Thermal and optical properties of these cured epoxy resins were investigated using thermogravimetric analyses, ultaviolet–visible scanning spectrophotometer, and Abbe refractometer, respectively. The results showed that three kinds of epoxy prepolymers had the similar thermal property and curing behavior. The sulfur atoms in DGETDBT and DGETP had contributed to an obvious increase in their refractive indexes, while the methyl group in DGEBA cut down its refractive index. The DGETDBT has the biggest refractive index (1.665), followed by the DGETP with 1.612. But the high cost and the lower thermal decomposition temperature of cured DGETDBT/MHHPA resin will limit its application. The refractive index of cured DGETP/MHHPA resin, with preferable thermal stability and acceptable price, is 1.595, which is higher than that of DGEBA/MHHPA resin (1.568). Therefore, DGETP resin can be expected to be a kind of the more effective encapsulant to light-emitting diode.

Choice set induced conflict, deliberation, and persistent preference

This research examines the roles of both approach–avoidance and approach–approach conflicts in the relationship between the degree of deliberation and persistence of preference for the chosen option. In three experiments, we reverse the negative effect of deliberation on persistence reported by Nordgren and Dijksterhuis (2009). In study 1A, we conceptually replicate Nordgren and Dijksterhuis’s results in a choice context with simultaneous presentation of options. In study 1B, we reversed this effect by making minor alterations to the choice set. When the choice set contains a brand with advantage on an irrelevant attribute with conflict caused by the more important attributes remains unchanged, deliberation leads to greater preference stability. In study 2, we obtain process evidence for a reduction in conflict and dominance structuring caused by discrimination in terms of an irrelevant attribute. In study 3, we found that when choice set induces conflict between two attractive options, deliberation causes persistent preference. In study 4, we vary perceived conflict without varying the choice set and replicate the effects obtained in experiments 1A and 1B. Thus, our studies provide evidence for the roles of approach–avoidance and approach–approach conflicts (Coombs and Avrunin 1988) in the deliberation–persistence relationship.

The Role of Indifference in Split-Ticket Voting

Previous studies of split-ticket voting have demonstrated that partisan ambivalence—countervailing affective cross-pressure that decreases preference stability—is positively related to an individual’s likelihood of casting a split ballot. While these findings are intuitive, recent methodological work regarding the measurement of ambivalence hints that indifference—i.e. the complete absence of affective political attachments—should produce a stronger positive effect on split-ticket voting than ambivalence. If partisan considerations are not central to the self-image of indifferent voters—who have little cognitive or emotional attachments from which they draw politically-relevant information—then they should be very likely to cast split ballots given that their nominal partisan attachments are only tentatively related to electoral choice. Drawing upon this distinction, I disaggregate indifferent individuals (i.e. those voters who are neither positively nor negatively oriented towards the parties) from ambivalent ones (i.e. those voters who possess mixed or conflicting affective attachments to both parties) and demonstrate that indifference has a greater positive effect on an individual’s propensity to engage in split-ticketing. I then show how the prevailing interval-level operationalization of ambivalence underestimates the true effect of indifference on split-ticketing.

De Gustibus Non Est Disputandum: An Experimental Investigation

The goal of this paper is to examine stability in preferences using the Stigler-Becker state-dependent framework. Using a randomized intervention that changes the opportunity sets of individuals we construct a unique panel data from an artefactual field experiment and evaluate whether the change in the state space influences our selected indicators of preferences: risk, competitiveness, and confidence. We find that there is considerable heterogeneity of preferences across individuals at a point in time; risk and competitive preferences inter-temporally are consistent with state-dependent preferences, while measures of confidence seem to depend on past experiences.

Prediction of Quaternary Spinel Oxides as Li-Battery Cathodes: Cation Site Preference, Metal Mixing, Voltage and Phase Stability

Using first-principles calculations, we explore the quaternary spinel oxides of the 3d transition metal series (Ti, V, Cr, Mn, Fe, Co, Ni) having pairs of transition metals in equal concentrations. We examine several properties of these materials relevant to Li-ion battery cathode applications. By examining cation site preference, delithiation voltage and thermodynamic stability, we predict five new quaternary spinel compounds which show promise as novel cathode materials: LiTiFeO4, LiCrFeO4, LiMnFeO4 and LiFeCoO4 and LiCoNiO4. The predicted compounds have tetrahedral Li/vacancy sublattice for efficient Li-transport, average voltage greater than 4.4 V, and are predicted to be stable ground states on a T = 0 K computed phase diagram. These predictions should be tested experimentally by synthesis and electrochemical measurements of these five compounds. For the lithiated oxides, we find predominant preference for the normal spinel structure (with Li in tetrahedrally coordinated sites), and for most of the delithiated oxides, transition metal cations spontaneously relax to non-spinel octahedral sites. We also find that metal mixing in these spinels is a strong function of charge state: most of the pairs of ternary transition metal oxide spinels tend to mix when lithiated and phase separate when delithiated.

Differential Effects of Voluntary Ethanol Consumption on Dopamine Output in the Nucleus Accumbens Shell of Roman High- and Low-Avoidance Rats: A Behavioral and Brain Microdialysis Study

The Roman high(RHA) and low-Avoidance (RLA) rats were selectively bred for rapid vs poor acquisition of two-way active avoidance behavior. These lines differ in numerous behavioral traits, with RLA rats being more fearful/anxious than RHA rats, and the latter being novelty-seekers and showing larger intake of, and preference for, addictive substances including ethanol (ETH). Moreover, several differences in central dopaminergic, serotonergic, and GABAergic functions have been reported in these two lines. Since those neural systems are involved in the regulation of ETH consumption, it was considered of interest to investigate: 1) the differences in ETH intake and preference between RHA and RLA rats, 2) the effects of ETH on DA release in the shell of the nucleus accumbens (AcbSh) using brain microdialysis. ETH solutions of increasing concentrations (2% - 10%) were presented on alternate days in a free choice with water. To examine ETH intake and preference stability, animals were subsequently switched to daily presentations of 10% ETH for 10 consecutive days. RHA rats consumed significantly larger amounts of ETH and displayed higher ETH preference than did RLA rats throughout the acquisition and maintenance phases. Following chronic exposure to ETH the animals were habituated to a restricted access to ETH schedule (2% ETH, 2 h per day × 4 days) before surgical implantation of a dialysis probe in the AcbSh. Under these experimental conditions, voluntary ETH intake (2%, 1 h, p.o.) produced a significant increase in accumbal DA output in RHA rats but not in their RLA counterparts. Finally, the i.p. administration of ETH (0.25 g/kg) to na?ve Roman rats produced a significant increment in accumbal DA output only in RHA rats. These results indicate that the mesolimbic dopaminergic system of RHA rats is more responsive to the effects of ETH than that of RLA rats.

Degenerate Hopf bifurcations, hidden attractors, and control in the extended Sprott E system with only one stable equilibrium

In this paper, we introduce an extended Sprott E system by a general quadratic control scheme with 3 arbitrary parameters for the new system. The resulting system can exhibit codimension-one Hopf bifurcations as parameters vary. The control strategy used can be applied to create degenerate Hopf bifurcations at desired locations with preferred stability. A complex chaotic attractor with only one stable equilibrium is derived in the sense of having a positive largest Lyapunov exponent. The chaotic attractor with only one stable equilibrium can be generated via a period-doubling bifurcation. To further suppress chaos in the extended Sprott E system coexisting with only one stable equilibrium, adaptive control laws are designed to stabilize the extended Sprott E system based on adaptive control theory and Lyapunov stability theory. Numerical simulations are shown to validate and demonstrate the effectiveness of the proposed adaptive control.

Особенности изменения индивидуальных предпочтений младших школьников в процессе обучения

The authors conducted a study that was aimed at studying the stability of individual preferences of younger school students in a situation of choice of educational tasks. The students choose and perform educational tasks during lessons, in a real learning process. Once in every one or two weeks, one training and four experimental lessons for each of the three subjects were conducted: mathematics, Russian language and literary reading. The subjects were students of II grade, Education Center № 975 in Moscow. The experiment was attended by 26 subjects – 12 girls and 14 boys. The study found that some individual learning preferences of younger students (for example, the use of lots, certain preferred type of the tasks and the desire to choose a partner with the same companion) are stable and equally manifest in various school subjects, the other manifest only in the framework of a particular educational subject.

Sleepiness, Choice Consistency, and Risk Preferences

We investigate the consistency and stability of individual risk preferences by manipulating cognitive resources. Participants are randomly assigned to an experiment session at a preferred time of day relative to their diurnal preference (circadian matched) or at a non-preferred time (circadian mismatched) and choose allocations between two risky assets (using the Choi et al., 2007, design). Consistency of behavior of circadian matched and mismatched subjects is statistically the same, however mismatched subjects tend to take more risks. We conclude that, consistent with several theories, preferences are rational yet can change depending on state-level cognitive resources.

Male Preference and Marital Stability in Cross River State, South South Nigeria

The issue of marital instability and its causes has received much attention of recent from experts in diverse fields of study. One of such causes that have been identified and taken up for study is male preference. This study takes a look the effects of male preference on marital stability in Cross River State. Respondents for the study were systematically selected from the population of study (ever married persons). Data for the study was gathered using qualitative techniques of data collection. Focus group discussions and in depth interviews were held with participants and key informants who were selected purposively for their experience in marriage and the issue under discourse. One important feature of the people studied is their lineage system. They are patrilineal in nature and prefer large families mostly for economic purposes as well as the continuity of the lineage. The study found that because it is a partriachal society, there was a strong preference for male children. It was also found that preference for male children was mostly expressed by the female participants, with the major reason being the stability of their marriage. Thus it was observed that, where there was a preference to fulfill the needs of the couple, the marriage was more likely to be unstable, especially in the later stages of the marriage. It was also observed that cultural norms and values prevalent in the state contributed immensely in enhancing and sustaining male preference. The paper therefore concludes that improvement in the status of women is very crucial in the task of reducing male preference. There is also the need for development, especially of the rural areas as one of the remedies for curbing those aspects of the culture that support male child preference, and its consequent implications on marital stability.

A rheumatoid arthritis magnetic resonance imaging contrast agent based on folic acid conjugated PEG-b-PAA@SPION.

Superparamagnetic iron oxide nanoparticles (SPIONs) offer unique properties for magnetic resonance imaging (MRI). Targeting imaging of rheumatoid arthritis in vivo requires a specific, magnetic sensitive and ultra-stable MRI contrast agent. In this study, SPIONs with a preferable colloid stability and optimized size were obtained by using an in situ polyol method with the diblock copolymer PEG-b-PAA acting as a surface ligand. Increasing the degree of polymerization (DP) of PAA from 18 to 36 to 57 led to the decreasing size of the iron oxide nanoparticles from 52 nm to 17 nm to 9 nm, respectively. Folic acid was conjugated onto PEG-PAAx@SPION as a specific targeting molecule for activated macrophages in a rheumatoid arthritis joint. To evaluate the stability and magnetic properties of the particle, a series of tests were conducted to evaluate and optimize the nanoparticles. In vitro endocytosis experiments confirmed the better performance of the folic acid conjugated SPIONs than the non-folic acid modified SPIONs. In vivo MRI clearly demonstrated the significant signal diminishment of the arthritis joint in antigen induced arthritis (AIA) rats by intravenous injection of the optimized nanoparticles FA-PEG-b-PAA36@SPION. These results indicated that FA-PEG-b-PAA36@SPION could serve as a promising candidate for the MRI of rheumatoid arthritis.

Evolutionary stability of prospect theory preferences

We demonstrate that in simple 2×2 games (cumulative) prospect theory preferences can be (semi-)evolutionarily stable, in particular, a population of players with prospect theory preferences is stable against more rational players, i.e. players with a smaller degree of probability weighting. We also show that in a typical game with infinitely many strategies, the “war of attrition”, probability weighting is (semi-)evolutionarily stable. Finally, we generalize to other notions of stability. Our results may help to explain why probability weighting is generally observed in humans, although it is not optimal in usual decision problems.

Biofeedback stimulation in patients with age-related macular degeneration: comparison between 2 different methods

ObjectiveTo evaluate changes in patient’s visual performance after rehabilitation training with 2 different biofeedback training programs offered by the MP-1 microperimeter. Spontaneous retinal location of preferred retinal loci (PRLs) and fixation stability are not always optimal for best visual performances. MP-1 microperimeter biofeedback techniques have been suggested as modalities for training for better fixation stability and to find a better location of the new PRL in a more useful area of the retina in nonoptimal cases. The MP-1 microperimeter offers different biofeedback strategies, such as acoustic biofeedback and structured light stimulus plus acoustic biofeedback. DesignRetrospective study. ParticipantsThirty subjects affected by age-related macular degeneration with absolute central scotoma. MethodsA standard protocol of examination before and after visual rehabilitation training was performed on all study subjects. Assessment included demographics data, visual acuity, fixation stability, retinal sensitivity, and reading speed. Rehabilitation training was performed with standard and structured stimulus biofeedback. The whole sample was divided into 2 groups of 15 patients attending the 2 different stimulation training biofeedback. ResultsMean reading speed was found to be significantly increased for both groups (p < 0.05 and p < 0.01). Also, a statistically significant improvement of fixation stability was registered for both groups (p < 0.01). Only patients trained with the flickering pattern biofeedback stimulation increased retinal sensitivity (p < 0.01). ConclusionsBoth regular biofeedback and flickering pattern biofeedback training seem to improve visual functions. More benefits seem to be accrued, however, with flickering pattern biofeedback training.

The worse eye is not as bad as it seems to be in AMD cases

ObjectiveIt is the aim of this study to review residual vision in the less used eye of patients with age-related macular degeneration (AMD) using modern concepts for residual visual functions in addition to traditional methods for assessing visual acuity. DesignThe study was designed as a retrospective, nonrandomized, observational case series. ParticipantsConsecutive cases tested with microperimetry instruments were identified from archives. Included were cases with diagnosed AMD of all age groups and all visual acuity levels. MethodsIn all cases, microperimetric technology was used to assess residual visual function. Outcome measures selected for analysis were visual acuity, preferred retinal loci (PRL) topography, fixation stability, and PRL span. ResultsData were collected and analyzed for both eyes from 51 patients with AMD low vision. There were 23 males and 28 females whose mean age was 84 (± 7) years. Within the group the difference in visual acuity estimates between the better seeing and the less used eye was statistically significant (p = 0.001). Similar positive statistical significant differences were noticed at all spatial frequencies (except at 6 cycles/degree) when testing contrast sensitivity. All other measurements were not statistically different between the better seeing and the poorer eye. This applies to the fixation stability and PRL span estimates. Almost half (49%) of the cases showed retinal noncorrespondence of PRLs between the 2 eyes. ConclusionsVisual acuity estimates are not a reliable measure for residual vision. The less used eye in AMD cases has much better residual vision than thought before according to modern outcome measures. This new concept should be taken into account by all practitioners and be applied during all low vision rehabilitation interventions.

Purification and Characterization of Superoxide Dismutase from Martianus Dermestoides Chevrola

In this paper, the superoxide dismutase fromMartianus dermestoidesis purified by the following methods: heat treatment, polyethylene concentration, Sephadex G-75 gel filtration, and DEAE-Sepharose FF ion exchange chromatography. The result shows that the purification multiple is 3.86, the activation yield is 21.89% and the specific activation of the enzyme is 447.6 U/mg. The purified SOD appears to be a sole protein on SDS-PAGE and the molecular weight is estimated to be 40.58 kDa. H2O2can obviously inhibit the enzyme activation and CHCl3-CH3CH2OH only demonstrates basically no inhibitory effect. The type of the dermestoides SOD might be Cu/Zn-SOD. After purification, some enzymatic characterizations of the SOD are studied. The optimum reaction temperature of purified SOD is 50°C. The optimum reaction pH value of purification is 6. The dermestoide SOD has a preferable stability below 50°C and at pH values between 5-8.

A Person Trade-Off Study to Estimate Age-Related Weights for Health Gains in Economic Evaluation

An increasing body of literature is exploring whether the age of the recipient of health care should be a criterion in how health care resources are allocated. The existing literature is constrained both by the relatively small number of age comparison groups within preference-elicitation studies, and by a paucity of methodological robustness tests for order and framing effects and the reliability and transitivity of preferences that would strengthen confidence in the results. This paper reports the results of a study aimed at estimating granulated age-related weights for health gains across the age spectrum that can potentially inform health care decision-making. A sample of 2,500 participants recruited from the health care consumer panels of a social research company completed a person trade-off (or 'matching') study designed to estimate age-related weights for 5- and 10-year life extensions. The results are presented in terms of matrices for alternative age comparisons across the age spectrum. The results revealed a general, although not invariable, tendency to give more weight to health gains, expressed in terms of life extensions, in younger age groups. In over 85% of age comparisons, the person trade-off exercises revealed a preference for life extensions by the younger of the two age groups that were compared. This pattern held regardless of the method of aggregating responses across study participants. Moreover, the relative weight placed on life extensions by the younger of the two age groups was generally, although not invariably, found to increase as the age difference between the comparator age groups increased. Further analyses revealed that the highest mean relative weight placed on life extensions was estimated for 30-year-olds when the ratio of means method was used to aggregate person trade-off responses across study participants. The highest mean relative weight placed on life extensions was estimated for 10-year-olds for 5-year life extensions and for 30-year-olds for 10-year life extensions, when the median of individual ratios method was used to aggregate person trade-off responses across study participants. Methodological tests framed around alternative referents in the person trade-off questions and the stability of preferences had no discernible effects on the study results. This study has produced new evidence on age-related weights for health gains that can potentially inform health care decision-making.

On the stability of preferences and attitudes before and after experiencing an electric vehicle

In this study, we investigate the extent to which experience affects individual preferences for specific electric vehicle characteristics, individual attitudes toward the environment, and the impact of the attitudes on the choice between an electric and a conventional vehicle. We use a two-wave stated preference experiment where data was collected before and after the respondents experienced an electric vehicle for three months. We estimate a hybrid choice model using jointly the stated choices before and after the test period. The results show that individual preferences change significantly after a real experience with an electric vehicle in the household. In particular, there are major changes in the preference for driving range, top speed, fuel cost, battery life and charging in city centres and train stations. In line with other studies, we find that environmental concern has a positive effect on the preference for EVs both before and after the test period, but the attitude itself and its effect on the choice of vehicle does not change.

Air-Fuel Ratio Fuzzy PID Control for Coal-Bed Gas Engine Based on Fuzzy PID Feedforward

In order to eliminate the adverse effects of coal-bed gas concentration disturbance to coal-bed gas engine air-fuel ratio control and the large pure time-delay existed in signal response of methane transducer, a fuzzy PID feedforward flow control plan was proposed for gas supply system. Fast and efficient flow control was performed in advance according to air-fuel ratio control requirements to eliminate air-fuel ratio control delays caused by the coal bed methane concentration disturbance. Based on the mentioned feedforward flow control plan, considering the premix coal-bed gas engine air-fuel ratio fluctuations arising from engine speed disturbances, a fuzzy PID closed-loop control scheme was proposed. By analyzing different air-fuel ratio control characteristics in transient condition and steady condition, the different closed-loop control of the air-fuel ratio was used to suppress air-fuel ratio fluctuations caused by engine condition changes. Compared to traditional PID control, the simulation results show that the air-fuel ratio fuzzy PID closed control scheme based on fuzzy PID feedforward flow control has ideal control effect, preferable stability and robustness. The air-fuel ratio control delays caused by the coal-bed methane concentration disturbance is well solved, and the problem of air-fuel ratio disturbance is well solved when the engines working condition changes, meeting the pre-mixed coal-bed gas engine air-fuel ratio control requirements.

The Spectral Model Construction between MODIS SWIR and HJ-1 CCD Blue Channel and its Application in Aerosol Retrieval

For the lacks of a shortwave infrared (SWIR) band, aerosol optical depth (AOD) retrieval by HJ-1 A/B CCD datasets is limited obviously. This article simulated the relationships of surface reflectance between HJ-1 CCD blue band and MODIS SWIR channel using typical object spectra from ASTER spectral library. A new surface reflectance determining model at HJ-1 CCD blue band was constructed by introducing MODIS SWIR channel as support, and was used in HJ-1 A/B CCD aerosol optical depth retrieval. The validation using AERONET ground measurements indicated that the proposed aerosol retrieval method has preferable accuracy and stability.

Beneficial metal stabilization mechanisms using simulated sludge incineration ash for ceramic products

AbstractBACKGROUNDThis study explored the feasibility of a waste to resource strategy by using incineration ash of sewage/waste‐water treatment sludge as part of the raw materials for ceramic processing. Reactions between metal oxides (CuO, ZnO), common metal containing form in incineration ash, and kaolinite based ceramic raw materials (kaolinite, mullite) were observed. The metal incorporation behavior was determined using quantitative X‐ray diffraction analysis.RESULTSThe optimal sintering temperature for copper incorporation was 1000°C, with CuAl2O4 phase dominating the system. For zinc incorporation, ZnAl2O4 and Zn2SiO4 formed in competition, with ZnAl2O4 found to predominate at temperatures higher than 1150°C. To determine the preferred phases for long‐term metal stability, a prolonged toxicity characteristic leaching procedure was carried out to quantify metal leaching performance and explore the leaching behavior. Metal leaching following incorporation in spinel leachates was significantly lower than those in oxide and silicate leachates, and the surface leaching behavior was also analyzed for the consideration of long‐term metal stability.CONCLUSIONThe overall results indicate that spinel formation is a preferred metal stabilization mechanism when incorporating sludge incineration ash into ceramic products and is also a key control step to safely implement this waste to resource strategy for a more sustainable engineering solution. © 2013 Society of Chemical Industry