bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nylon 6/Brazilian clay membranes prepared by phase inversion
Authors: Leite Amanda M. D. , Maia Larissa F. , Araújo Edcleide M. , Lira Hélio L. 
Published: April 2009

AbstractMicroporous membranes were synthesized from a polymer nanocomposite material, intercalated montmorillonite clay/nylon 6, by an immersion–precipitation method in a water bath. This membrane was skinless and was composed of cellular pores and sheaflike crystallites, which were interwoven into a bicontinuous structure. In contrast, pure nylon 6, precipitated under the same conditions, yielded a skinned asymmetric membrane. The X‐ray diffraction patterns showed that the nanocomposites and the membranes exhibited exfoliated structures. By differential scanning calorimetry, it was observed that the clay probably acted as a reinforcing filler, increasing the crystallinity degree of the nanocomposites, but it was practically unchanged in the membranes. Through photomicrographs obtained by scanning electron microscopy, it was possible to verify that all the membranes exhibited an asymmetric morphology with a well‐defined porous structure and a tight skin with a cellular sublayer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mechanical properties of silane‐treated, silica‐particle‐filled polyisoprene rubber composites: Effects of the loading amount and alkoxy group numbers of a silane coupling agent containing mercapto groups
Authors: Nakamura Yoshinobu , Honda Hiroaki , Harada Atsushi , Fujii Syuji , Nagata Kazuya 
Published: April 2009

AbstractThe surface treatment of spherical silica particles with a silane coupling agent with mercapto groups was carried out. The treated silica particles were incorporated within polyisoprene and then vulcanized. The effects of the loading amount and alkoxy group number of silane on the stress–strain curve of the filled composite were investigated. For this purpose, silanes with dialkoxy and trialkoxy structures were used. The loading amount of silane on the silica surface was varied from 1 to 8 times the amount required for monolayer coverage. The stress at the same strain increased with the silane treatment, and it was higher in the dialkoxy structure than in the trialkoxy structure above 300% strain. There was no significant influence of the loading amount on the stress for the trialkoxy silane structure. However, the stress was influenced by the loading amount, and the maximum stress was observed at 4 times the silane amount required for monolayer coverage for the dialkoxy structure. The stress had a good relationship with the crosslinking density of silica‐filled polyisoprene rubber (measured with a swelling test). The reinforcement effect by the silane treatment of silica was found to be affected strongly both by the entanglement of the silane chain and polyisoprene rubber matrix and by the crosslinking reaction between the mercapto group of silane and polyisoprene rubber in the interfacial region. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Misclassification rates, critical values and size of the design in measurement systems capability studies
Authors: Zappa D. , Deldossi L. 
Published: April 2009

AbstractMeasurement systems capability analysis aims to test if the variability of a measurement system is small relative to the variability of a monitored process. At present some open questions are related both to the interpretation of the critical values of the indices typically used by practitioners to assess the capability of a gauge and to the choice of the size of the experimental design to test the repeatability and the reproducibility of the measurement process. In this paper, starting from the misclassification rates of a measurement system, we present a solution to these issues. Copyright © 2009 John Wiley & Sons, Ltd.
On the detection of high‐frequency oscillations in short gamma‐ray bursts
Authors: Zhilyaev B.E. , Dubinovska D. 
Published: April 2009

AbstractIn this work we present the results of an investigation aimed at a search for an oscillatory phenomenon during short gamma‐ray bursts. The wavelet technique, used for this analysis, is applied to the data from the BATSE 3B catalogue. We have detected oscillations, which periods are found to be in the milliseconds range and their amplitudes up to dozens of percents. A possible scenario for such a phenomenon is the coalescence of stellar‐mass black holes and neutron stars. During the coalescence process the matter orbiting the black hole produces rapid, periodic phenomena. Such system will also emit gravitational waves which cause the orbital radius to decrease and leads to the emission of a chirp of radiation. Estimates lead to a timescale of milliseconds for the coalescence process and oscillation frequencies of hundreds of Hz. The gamma‐ray bursts considered in this paper, show both frequencies and survival times of oscillations close to the mentioned values. A chirp phenomenon is also present. We therefore argue in favor of the black hole – neutron star coalescence as a scenario for the production of short gamma‐ray bursts (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two‐dimension potentials which generate spatial families of orbits
Authors: Anisiu M.‐C. , Bozis G. 
Published: April 2009

AbstractWe consider the following case of the 3D inverse problem of dynamics: Given a spatial two‐parametric family of curves f (x, y, z) = c1, g (x, y, z) = c2, find possibly existing two‐dimension potentials under whose action the curves of the family are trajectories for a unit mass particle. First we establish the conditions which must be fulfilled by the family so that potentials of the form w (y, z) give rise to the curves of the family, and we present some applications. Then we examine briefly the existence of potentials depending on (x, z), respectively (x, y), which are compatible with the given family (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The chromospherically active binary star EI Eridani: II. Long‐term Doppler imaging
Authors: Washuettl A. , Strassmeier K.G. , Weber M. 
Published: April 2009

AbstractData from 11 years of continuous spectroscopic observations of the active RS CVn‐type binary star EI Eridani – gained at NSO/McMath‐Pierce, KPNO/Coudé Feed and during the MUSICOS 98 campaign – were used to obtain 34 Doppler maps in three spectroscopic lines for 32 epochs, 28 of which are independent of each other. Various parameters are extracted from our Doppler maps: average temperature, fractional spottedness, and longitudinal and latitudinal spot‐occurrence functions. We find that none of these parameters show a distinct variation nor a correlation with the proposed activity cycle as seen from photometric long‐term observations. This suggests that the photometric brightness cycle may not necessarily be due to just a cool spot cycle. The general morphology of the spot pattern remains persistent over the whole period of 11 years. A large cap‐like polar spot was recovered from all our images. A high degree of variable activity was noticed near latitudes of ≈60–70° where the appendages of the polar spot emerged and dissolved (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Intermediate‐term variations in solar radius during solar cycle 23
Authors: Kiliç H. , Golbasi O. , Chollet F. 
Published: April 2009

AbstractIn this study, we look for the mid‐term variations in the daily average data of solar radius measurements made at the Solar Astrolabe Station of TUBITAK National Observatory (TUG) during solar cycle 23 for a time interval from 2000 February 26 to 2006 November 15. Due to the weather conditions and seasonal effect dependent on the latitude, the data series has the temporal gaps. For spectral analysis of the data series, thus, we use the Date Compensated Discrete Fourier Transform (DCDFT) and the CLEANest algorithm, which are powerful methods for irregularly spaced data. The CLEANest spectra of the solar radius data exhibit several significant mid‐term periodicities at 393.2, 338.9, 206.5, 195.2, 172.3 and 125.4 days which are consistent with periods detected in several solar time series by several authors during different solar cycles. The knowledge relating to the origin of solar radius variations is not yet present. To see whether these variations will repeat in next cycles and to understand how the amplitudes of such variations change with different phases of the solar cycles, we need more systematic efforts and the long‐term homogeneous data. Since most of the periodicities detected in the present study are frequently seen in solar activity indicators, it is thought that the physical mechanisms driving the periodicities of solar activity may also be effective in solar radius variations (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New magnetic field measurements of β Cephei stars and slowly pulsating B stars
Authors: Hubrig S. , Briquet M. , De Cat P. , Schöller M. , Morel T. , Ilyin I. 
Published: April 2009

AbstractWe present the results of the continuation of our magnetic survey with FORS 1 at the VLT of a sample of B‐type stars consisting of confirmed or candidate β Cephei stars and Slowly Pulsating B (hereafter SPB) stars, along with a small number of normal B‐type stars. A weak mean longitudinal magnetic field of the order of a few hundred Gauss was detected in three β Cephei stars and two stars suspected to be β Cephei stars, in five SPB stars and eight stars suspected to be SPB stars. Additionally, a longitudinal magnetic field at a level larger than 3σ has been diagnosed in two normal B‐type stars, the nitrogen‐rich early B‐type star HD 52089 and in the B5 IV star HD 153716. Roughly one third of β Cephei stars have detected magnetic fields: Out of 13 β Cephei stars studied to date with FORS 1, four stars possess weak magnetic fields, and out of the sample of six suspected β Cephei stars two show a weak magnetic field. The fraction of magnetic SPBs and candidate SPBs is found to be higher: Roughly half of the 34 SPB stars have been found to be magnetic and among the 16 candidate SPBs eight stars possess magnetic fields. In an attempt to understand why only a fraction of pulsating stars exhibit magnetic fields, we studied the position of magnetic and non‐magnetic pulsating stars in the H‐R diagram. We find that their domains in the H‐R diagram largely overlap, and no clear picture emerges as to the possible evolution of the magnetic field across the main sequence. It is possible that stronger fields tend to be found in stars with lower pulsating frequencies and smaller pulsating amplitudes. A somewhat similar trend is found if we consider a correlation between the field strength and the v sin i ‐values, i.e. stronger magnetic fields tend to be found in more slowly rotating stars (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The estimations of neutron star mass and radius by the kHz QPOs
Authors: Zhang C.M. 
Published: April 2009

AbstractThe kHz quasi‐periodic oscillations (QPOs) have been detected by the RXTE satellite in about thirty neutron stars (NSs) in low mass X‐ray binaries (LMXBs), which are usually interpreted to be related to the Keplerian motions in the orbit close to NS surface where the accreted matter is sucked onto the star. Based on the MHD Alfvén wave oscillation model and the relativistic precession model for the neutron star (NS) kHz QPOs, estimations of mass M and radius R of some NSs are given, which can give clues to evaluate the models. Furthermore, comparisons with theoretical M ‐R relations by stellar equations of state (EOSs) are presented (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic activity on 12 Cam and 29 Dra from long‐term photometry
Authors: Zboril M. , Messina S. 
Published: April 2009

AbstractWe present newly discovered magnetic cycles of two late‐type and long‐period SB1 systems: 12 Cam and 29 Dra. The long‐term photometry study revealed the presence of magnetic multiperiodic cycles on both stars, namely 14.8 and 8.5 yr for 12 Cam and 20.3, 11.1, and 7.6 yr for 29 Dra. Furthermore, the modelling of the V ‐band light curves revealed the existence of two active longitudes on 12 Cam and probably on 29 Dra as well. Both stars show changes of rotational period. The 12 Cam is the slowest rotating star whose activity cycle has been determined. The activity cycles determined by us allow us to extend to the slower rotation regime and to improve the significance of the empirical relation between rotation period and magnetic cycle length (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
How semiregular are irregular variables?
Authors: Lebzelter T. , Obbrugger M. 
Published: April 2009

AbstractWe investigate the question whether there is a real difference in the light change between stars classified as semiregular (SRV) or irregular (Lb) variables by analysing photometric light curves of 12 representatives of each class. Using Fourier analysis we try to find a periodic signal in each light curve and determine the S/N of this signal. For all stars, independent of their variability class we detect a period above the significance threshold. No difference in the measured S/N between the two classes could be found. We propose that the Lb stars can be seen as an extension of the SRVs towards shorter periods and smaller amplitudes. This is in agreement with findings from other quantities which also showed no marked difference between the two classes (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
To what extent do investors in a financial market anchor their judgments excessively? Evidence from the Hong Kong horserace betting market
Authors: Johnson Johnnie Eric Victor , Schnytzer Adi , Liu Shuang 
Published: April 2009

AbstractA naturalistic study was employed to explore a new form of “basic anchoring.” In particular, we examined the degree to which decision makers in a financial market, the horserace betting market, anchored their probability judgments excessively on a factor present in the environment at the time the judgments were made and which was relevant and informative to the judgment: the advantage afforded by a horse's barrier‐position (BP). The results demonstrated that under certain conditions bettors anchored excessively on BP information revealed at previous race meetings, but not on the most recent race outcomes. In fact, bettors appeared to use the most recent race outcomes appropriately when forming probability estimates; but only when the results were in line with, what were likely to be, their expectations of BP advantage. Bettors with varying levels of expertise were shown to be subject to excessive anchoring, although greater expertise was generally associated with less excessive anchoring. The paper concludes that the manner and degree of basic anchoring in real‐world environments is complex. Copyright © 2009 John Wiley & Sons, Ltd.
Criterion knowledge: A moderator of using the recognition heuristic?
Authors: Hilbig Benjamin E. , Pohl Rüdiger F. , Bröder Arndt 
Published: April 2009

AbstractThe recognition heuristic (RH) claims that people base inferences on recognition only. This has been questioned by several studies which found that additional knowledge was influential. However, in some of these studies, participants' additional knowledge might have encompassed criterion knowledge thus rendering any inferential strategy superfluous. The present study was therefore designed to test the effect of criterion knowledge on use or non‐use of the RH. Eighty‐one participants made pair‐wise comparisons with respect to the size of Belgian cities and also provided estimates of the cities' actual size. We found that relative criterion knowledge (i.e., knowledge about the relative position of an object on the criterion dimension) did indeed play some role, but its exclusion left the main critical findings intact, nonetheless. We thus conclude that previous studies conducted in the paradigm of natural recognition should not be generally refuted by the argument of participants possessing criterion knowledge. Copyright © 2009 John Wiley & Sons, Ltd.
Goal attainment as a resource: The cushion effect in risky choice above a goal
Authors: Jeffrey Scott A. , Onay Selcuk , Larrick Richard P. 
Published: April 2009

AbstractGoals are a ubiquitous part of life and have been shown to change behavior in many domains. This research studied the influence of goal attainment on risky choice behavior. Previous research has shown that goals tend to increase risk‐seeking behavior when potential outcomes fall below a goal. We examined a new problem: Choice behavior when all potential outcomes in a choice set achieve or exceed the goal. Two studies show a “cushion effect” of goal attainment on choice under risk. When all possible outcomes of all options are above a salient and specific goal, decision makers are more likely to choose a risky option over a certain outcome with equal expected value (EV). We hypothesized that the attainment of a goal serves as a cushion that softens the negative emotions associated with receiving a gamble's low outcome. This allows risk taking that would otherwise be unattractive. Copyright © 2009 John Wiley & Sons, Ltd.
Why are maximizers less happy than satisficers? Because they maximize positive and negative outcomes
Authors: Polman Evan 
Published: April 2009

AbstractAlthough extant research suggests maximizing is related to objectively positive outcomes (e.g., job offers), I propose maximizing may be simultaneously and positively related to objectively negative outcomes (e.g., job rejections). Specifically, I argue maximizers bear more instances of positive and negative outcomes than satisficers, and that in spite of their positive outcomes—yet because of their negative outcomes—maximizers are less happy than satisficers. In Study 1, participants took the alternate uses test; as expected, maximizing was related to seeking alternatives, yet, maximizing was also related to seeking low‐quality alternatives. Moreover, the number of low‐quality alternatives partially mediated the relationship between maximizing and negative affect. In Study 2, the impact of maximizing on experiencing negative affect was further assessed by examining whether maximizing is related to seeking and choosing low‐quality alternatives. Participants played the Iowa Gambling Task; it was found maximizing was related to alternating among decks, and in particular, sampling bad decks; ultimately, maximizing was related to winning less money, and experiencing more negative affect. Finally, in Study 3, participants responded to questionnaires about positive and negative life outcomes; it was found that maximizing was simultaneously related to experiencing more positive and more negative outcomes, and that negative outcomes predicted happiness to a greater degree than positive outcomes. These findings suggest an irony of maximizing: It produces both positive and negative outcomes, contributing to literature explaining why maximizers are less happy than satisficers, and ultimately whether happiness is a matter of choice. Copyright © 2009 John Wiley & Sons, Ltd.
Semantic coherence and fallacies in estimating joint probabilities
Authors: Wolfe Christopher R. , Reyna Valerie F. 
Published: April 2009

AbstractIn three experiments on joint probability estimation, gist representations were manipulated with analogies, and the suboptimal strategy of ignoring relevant denominators was counteracted with training in using 2 × 2 tables to clarify joint probability estimates. The estimated probabilities of two events, as well as their conjunctive and disjunctive probabilities, were assessed against two benchmarks, logical fallacies and semantic coherence—a constellation of estimates consistent with the relationship among sets. Fuzzy‐trace theory (FTT) predicts that analogies will increase semantic coherence, and a table intervention affecting denominator neglect will both increase semantic coherence and reduce fallacies. In all three experiments, analogies increased semantic coherence. In both experiments training participants to use 2 × 2 tables, such tables reduced fallacies and increased semantic coherence. As the relations among sets in the problem materials progressed in cognitive complexity from identical sets, mutually exclusive sets, and subsets to overlapping sets, fallacies generally increased, and semantic coherence generally decreased. These findings indicate that denominator neglect is pervasive, but that it can be remedied with a straightforward intervention that clarifies relations among sets. Further, intuitive gist‐based probability estimation can be improved through the use of simple analogies. Copyright © 2009 John Wiley & Sons, Ltd.
Hydrogels as extracellular matrix mimics for 3D cell culture
Authors: Tibbitt Mark W. , Anseth Kristi S. 
Published: April 2009

AbstractMethods for culturing mammalian cells ex vivo are increasingly needed to study cell and tissue physiology and to grow replacement tissue for regenerative medicine. Two‐dimensional culture has been the paradigm for typical in vitro cell culture; however, it has been demonstrated that cells behave more natively when cultured in three‐dimensional environments. Permissive, synthetic hydrogels and promoting, natural hydrogels have become popular as three‐dimensional cell culture platforms; yet, both of these systems possess limitations. In this perspective, we discuss the use of both synthetic and natural hydrogels as scaffolds for three‐dimensional cell culture as well as synthetic hydrogels that incorporate sophisticated biochemical and mechanical cues as mimics of the native extracellular matrix. Ultimately, advances in synthetic–biologic hydrogel hybrids are needed to provide robust platforms for investigating cell physiology and fabricating tissue outside of the organism. Biotechnol. Bioeng. 2009;103: 655–663. © 2009 Wiley Periodicals, Inc.
Antioxidant and antibacterial activities of eugenol and carvacrol‐grafted chitosan nanoparticles
Authors: Chen Fei , Shi Zhilong , Neoh K.G. , Kang E.T. 
Published: April 2009

AbstractEssential oils are known to possess antimicrobial and antioxidant activity while chitosan is a biocompatible polymer with antibacterial activity against a broad spectrum of bacteria. In this work, nanoparticles with both antioxidant and antibacterial properties were prepared by grafting eugenol and carvacrol (two components of essential oils) on chitosan nanoparticles. Aldehyde groups were first introduced in eugenol and carvacrol, and the grafting of these oils to chitosan nanoparticles was carried out via the Schiff base reaction. The surface concentration of the grafted essential oil components was determined by X‐ray photoelectron spectroscopy (XPS). The antioxidant activities of the carvacrol‐grafted chitosan nanoparticles (CHCA NPs) and the eugenol‐grafted chitosan nanoparticles (CHEU NPs) were assayed with diphenylpicrylhydrazyl (DPPH). Antibacterial assays were carried out with a representative gram‐negative bacterium, Escherichia coli (E. coli) and a gram‐positive bacterium, Staphylococcus aureus (S. aureus). The grafted eugenol and carvacrol conferred antioxidant activity to the chitosan nanoparticles, and the essential oil component‐grafted chitosan nanoparticles achieved an antibacterial activity equivalent to or better than that of the unmodified chitosan nanoparticles. Cytotoxicity assays using 3T3 mouse fibroblast showed that the cytotoxicity of CHEU NPs and CHCA NPs were significant lower than those of the pure essential oils. Biotechnol. Bioeng. 2009; 104: 30–39 © 2009 Wiley Periodicals, Inc.