Researching trust in Wikipedia

As the use of collaborative online encyclopedias such as Wikipedia grows, so does the need for research on how users evaluate its credibility. In this paper we compare three experimental approaches to study trust in Wikipedia, namely think aloud, eye-tracking, and online questionnaires. The advantages and disadvantages of each method are discussed. We conclude that it is best to use multiple methods when researching information trust, as each single one of the discussed methods alone does not give all possible information

Resonance polarization and phase-mismatched CARS of pheophytin b excited in the Qy band

Resonance polarization and phase-mismatched coherent anti-Stokes Raman scattering (CARS) measurements were performed on pheophytin b dissolved in acetone excited in the Qy absorption band, where strong broad fluorescence makes spontaneous Raman spectroscopy impossible. The phase-mismatching technique was applied to suppress solvent background and used in combination with the polarization-sensitive CARS technique to measure directly the x1111(3) and x1221(3) components to estimate depolarization ratios. The spectra were fitted by a non-linear least-squares procedure yielding vibrational band parameters. Some CARS dispersion information on the vibrational amplitudes was obtained by varying the pump wavelength. CARS excitation profiles based on transform theory were calculated and partly explain the observed amplitude dispersion. The application of the combined phase-mismatched polarization CARS technique may be useful in many other cases of highly fluorescing molecules when resonantly excited

Polarization-sensitive resonance CSRS of deoxy-and oxyhaemoglobin

Polarization-sensitive coherent Stokes Raman scattering (CSRS) measurements of oxy- and deoxyhaemoglobin in aqueous solutions are reported. The excitation wavelengths used were chosen in the region of the Q absorption bands to achieve twofold electronic resonance. The dispersion profiles of all independent susceptibility (3) components and purely anisotropic and anti-symmetric scattering contributions were resolved within the frequency non-degenerate CSRS scheme. Eight bands of oxyhaemoglobin and five bands of deoxyhaemoglobin were observed in the range 1500-1680 cm-1. Simultaneously fitting sets of polarization spectra provided vibrational parameters (positions, bandwidths, amplitudes, phases and CSRS depolarization ratios) for each compound. Major bands were assigned to the non-totally symmetric v10, v11 and v19 modes of the porphyrin macrocycle. The phases calculated exhibited a correlation with the symmetry of the vibrations. On the basis of the spectral fits, the three additional peaks arising in the oxyhaemoglobin spectra could be ascribed to the bands of intermediate deoxyhaemoglobin. The occurrence is due to the partial photolysis of oxyhaemoglobin. Vibrational parameters of these bands were found to be essentially similar to the parameters of the bands observed in the spectra of the stable deoxyhaemoglobin. Despite the asymmetric character predicted, the major bands were all contributed to by a considerable isotropic component. A decrease in the depolarization ratio PR1212 of the anomalously polarized v19 mode from 7.7 in oxyhaemoglobin to 4.3 in deoxyhaemoglobin was observed. Such a decrease in anti-symmetric character of the vibration on release of the ligand supports the occurrence of deformation of the haem ring system

Factual accuracy and trust in information: the role of expertise

In the past few decades, the task of judging the credibility of information has shifted from trained professionals (e.g., editors) to end users of information (e.g., casual Internet users). Lacking training in this task, it is highly relevant to research the behavior of these end users. In this article, we propose a new model of trust in information, in which trust judgments are dependent on three user characteristics: source experience, domain expertise, and information skills. Applying any of these three characteristics leads to different features of the information being used in trust judgments; namely source, semantic, and surface features (hence, the name 3S-model). An online experiment was performed to validate the 3S-model. In this experiment, Wikipedia articles of varying accuracy (semantic feature) were presented to Internet users. Trust judgments of domain experts on these articles were largely influenced by accuracy whereas trust judgments of novices remained mostly unchanged. Moreover, despite the influence of accuracy, the percentage of trusting participants, both experts and novices, was high in all conditions. Along with the rationales provided for such trust judgments, the outcome of the experiment largely supports the 3S-model, which can serve as a framework for future research on trust in information

Polarization-xensitive CARS of excited-state rhodamine 6G: induced ansisotropy effects on depolarization ratios

Resonance polarization-sensitive coherent anti-Stokes Raman scattering (PS CARS) spectra of the electronic ground state and excited singlet S1 state of rhodamine 6G in ethanol were obtained with the use of the pump-probe technique with nanosecond time resolution. Variation of the polarization orientation of the pump laser beam showed differences in the excited-state spectra due to optically induced anisotropy. The pure electronic susceptibility of ground-state rhodamine 6G was shown to be small in comparison with nonresonant susceptibility of the solvent, and was neglected in further analyses. The pure electronic susceptibility of excited rhodamine 6G was examined by coherent ellipsometry. The complex third-order susceptibility was analyzed by means of a nonlinear least-squares fit program that provides detailed information on the Raman vibration parameters, including depolarization ratios and phases. In the isotropic case the measured depolarization ratios are close to 1/3, whereas in the anisotropic case, ground-state depolarization ratios are 0.5–0.65 and in the excited state 0.17–0.22. Estimated depolarization ratio changes in ground-state and excited-state rhodamine 6G are in agreement with theoretically predicted values in the case of induced anisotropy under the assumption of parallel dipole moments of the CARS process. The effects of possible changed molecular structure or symmetry and changed enhancement of different electronic transitions cannot be determined without making some assumptions about one of these effects. The obtained phase differences reflect different enhancements and vibronic coupling for ground-state and excited-state vibrations. The ground-state and excited-state hyperpolarizabilities, $\gamma{^E}{s_0}$ and $\gamma{^E}{s_1}$, of rhodamine 6G were estimated to be 3.8·10−35 esu and 27.4·10−35 esu, respectively

Czytelność Wikipedii

Wikipedia is becoming widely acknowledged as a reliable source of encyclopedic information. However, concerns have been expressed about its readability. Wikipedia articles might be written in a language too difficult to be understood by most of its visitors. In this study, we apply the Flesch reading ease test to all available articles from the English Wikipedia to investigate these concerns. The results show that overall readability is poor, with 75 percent of all articles scoring below the desired readability score. The ‘Simple English’ Wikipedia scores better, but its readability is still insufficient for its target audience. A demo of our methodology is available at www.readabilityofwikipedia.com.Wikipedia jest powszechnie uznawana za wiarygodne źródło informacji encyklopedycznej. Pewnym problemem jest jednak jej czytelność. Artykuły Wikipedii bywają napisane w sposób niezrozumiały dla przeciętnego użytkownika. Do zbadania tego aspektu w odniesieniu do wszystkich dostępnych artykułów angielskiej wersji Wikipedii wykorzystano indeks czytelności Flescha. W rezultacie badań okazało się, że czytelność Wikipedii jest na niskim poziomie: 75% z wszystkich artykułów plasuje się poniżej spodziewanego poziomu. W teście lepiej wypada Wikipedia w wersji uproszczonej (Simple English Wikipedia), ale i jej czytelność okazuje się nieodpowiednia dla docelowej grupy użytkowników. Wersja demonstracyjna przyjętej metody badań dostępna jest na stronie: www.readabilityofwikipedia.com