5 − 4 ≠ 4 − 3: On the Uneven Gaps between Different Levels of Graded User Satisfaction in Interactive Information Retrieval Evaluation

Similar to other ground truth measures, graded user satisfaction has been frequently employed as a continuous variable in information retrieval evaluation based on the assumption that intervals between adjacent grades are quantitatively equal. To examine the validity of equal-gap assumption and explore dynamic perceptual thresholds triggering grade changes in search evaluation, we investigate the extent to which users are sensitive to changes in search efforts and outcomes across different gaps of graded satisfaction. Experiments on four user study datasets (15,337 queries) indicate that 1) User satisfaction sensitivity, especially to offline evaluation metrics, changes significantly across gaps in satisfaction scale; 2) the size and direction of changes in sensitivity vary across study settings, search types, and intentions, especially within “3-5” scale subrange. This study speaks to the fundamentals of user-centered evaluation and advances the knowledge of heterogeneity in satisfaction sensitivity to search efforts and gains and implicit changes in evaluation thresholds

Far-Infrared Spectroscopy of Cationic Polycyclic Aromatic Hydrocarbons: Zero Kinetic Energy Photoelectron Spectroscopy of Pentacene Vaporized from Laser Desorption

doi:10.1088/0004-637X/715/1/485The distinctive set of infrared (IR) emission bands at 3.3, 6.2, 7.7, 8.6, and 11.3 μm are ubiquitously seen in a wide variety of astrophysical environments. They are generally attributed to polycyclic aromatic hydrocarbon (PAH) molecules. However, not a single PAH species has yet been identified in space, as the mid-IR vibrational bands are mostly representative of functional groups and thus do not allow one to fingerprint individual PAH molecules. In contrast, the far-IR (FIR) bands are sensitive to the skeletal characteristics of a molecule, hence they are important for chemical identification of unknown species. With an aim to offer laboratory astrophysical data for the Herschel Space Observatory, Stratospheric Observatory for Infrared Astronomy, and similar future space missions, in this work we report neutral and cation FIR spectroscopy of pentacene (C22H14), a five-ring PAH molecule. We report three IR active modes of cationic pentacene at 53.3, 84.8, and 266 μm that may be detectable by space missions such as the SAFARI instrument on board SPICA. In the experiment, pentacene is vaporized from a laser desorption source and cooled by a supersonic argon beam. We have obtained results from two-color resonantly enhanced multiphoton ionization and two-color zero kinetic energy photoelectron (ZEKE) spectroscopy. Several skeletal vibrational modes of the first electronically excited state of the neutral species and those of the cation are assigned, with the aid of ab initio and density functional calculations. Although ZEKE is governed by the Franck-Condon principle different from direct IR absorption or emission, vibronic coupling in the long ribbon-like molecule results in the observation of a few IR active modes. Within the experimental resolution of ~7 cm-1, the frequency values from our calculation agree with the experiment for the cation, but differ for the electronically excited intermediate state. Consequently, modeling of the intensity distribution is difficult and may require explicit inclusion of vibronic interactions.This work is supported by the National Aeronautics and Space Administration under award No. NNX09AC03G. A.L. is supported in part by the NSF grant AST 07-07866, a Spitzer Theory grant and a Herschel Theory grant

Excited-State Proton Transfer of Photoexcited Pyranine in Water Observed by Femtosecond Stimulated Raman Spectroscopy

We use femtosecond stimulated Raman spectroscopy (FSRS) to illuminate the choreography of intermolecular excited-state proton transfer (ESPT) of photoacid pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid, HPTS) in water. The multidimensional reaction coordinate responsible for photoacidity is revealed to involve sequential activation of characteristic skeletal motions during the ca. 1 ps preparation stage preceding ESPT. The initial ring-coplanarity breaking follows in-plane ring breathing (191 cm⁻¹), and is facilitated by HPTS ring wagging (108 cm⁻¹) and ring-H out-of-plane motions (321, 362, 952 cm⁻¹), which largely decay within ~1 ps. ESPT then occurs with intrinsic inhomogeneity via various number of intervening water molecules over relatively larger distances than those in acetate-water system. The intricate relationship between the time-resolved excited-state vibrational modes of HPTS reveals the essential role of coherent low-frequency skeletal motions gating ESPT, and the multi-staged proton-transfer process having the kinetic isotope effect (KIE) value of 3–4 in aqueous solution on the 5–200 ps timescale.Keywords: Photoacid, Excited-state proton transfer, Molecular conformational dynamics, Femtosecond stimulated Raman spectroscopy, Low-frequency skeletal motions, Hydrogen bond dynamic

In-situ characterization of femtosecond laser-induced crystallization in borosilicate glass using time-resolved surface third-harmonic generation

Coherent phonon dynamics in condensed-phase medium are responsible for important material properties including thermal and electrical conductivities. We report a structural dynamics technique, time-resolved surface third-harmonic generation (TRSTHG) spectroscopy, to capture transient phonon propagation near the surface of polycrystalline CaF₂ and amorphous borosilicate (BK7) glass. Our approach time-resolves the background-free, high-sensitivity third harmonic generation (THG) signal in between the two crossing near-IR pulses. Pronounced intensity quantum beats reveal the impulsively excited low-frequency Raman mode evolution on the femtosecond to picosecond timescale. After amplified laser irradiation, danburite-crystal-like structure units form at the glass surface. This versatile TRSTHG setup paves the way to mechanistically study and design advanced thermoelectrics and photovoltaics.Article Copyright 2013 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This is the publisher’s final pdf. The published article can be found at: http://scitation.aip.org/content/aip/journal/apl

Distinct broadband third-harmonic generation on a thin amorphous medium–air interface

We achieve a series of distinct broadband third-harmonic generation (THG) signals at the amorphous glass–air interface attributed to third-order and cascaded third-order nonlinear processes. A novel THG laser sideband arises from cascaded interaction between fundamental pulses and the cascaded four-wave mixing signals. The spatially separated THG sidebands with distinct spectral profiles manifest femtosecond quantum beats. Using a versatile setup with two crossing near-IR pulses temporally delayed to each other, we design an incident pulse polarization control method on the THG sideband lasers and also acquire the low-frequency surface Raman spectrum of the amorphous medium.KEYWORDS: Ultraviolet, Femtosecond phenomena, Ultrafast nonlinear optics, Harmonic generation and mixing, Nonlinear optics, four-wave mixingThis paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.osa.org/en-us/home/. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law

Zero kinetic energy photoelectron spectroscopy of jet cooled benzo[a]pyrene from resonantly enhanced multiphoton ionization

We report zero kinetic energy (ZEKE) photoelectron spectroscopy of benzo[a]pyrene (BaP) via resonantly enhanced multiphoton ionization (REMPI). Our analysis concentrates on the vibrational modes of the first excited state (S₁) and those of the ground cationic state (D₀). Similar to pyrene, another peri-condensed polycyclic aromatic hydrocarbon we have investigated, the first two electronically excited states of BaP exhibit extensive configuration interactions. However, the two electronic states are of the same symmetry, hence vibronic coupling does not introduce any out-of-plane modes in the REMPI spectrum, and Franck-Condon analysis is qualitatively satisfactory. The ZEKE spectra from the in-plane modes observed in the REMPI spectrum demonstrate strong propensity in preserving the vibrational excitation of the intermediate state. Although several additional bands in combination with the vibrational mode of the intermediate state are identifiable, they are much lower in intensity. This observation implies that the molecular structure of BaP has a tremendous capability to accommodate changes in charge density. All observed bands of the cation are IR active, establishing the role of ZEKE spectroscopy in mapping out far infrared bands for astrophysical applications

Grading by AI makes me feel fairer? How different evaluators affect college students’ perception of fairness

IntroductionIn the field of education, new technologies have enhanced the objectivity and scientificity of educational evaluation. However, concerns have been raised about the fairness of evaluators, such as artificial intelligence (AI) algorithms. This study aimed to assess college students’ perceptions of fairness in educational evaluation scenarios through three studies using experimental vignettes.MethodsThree studies were conducted involving 172 participants in Study 1, 149 in Study 2, and 145 in Study 3. Different evaluation contexts were used in each study to assess the influence of evaluators on students’ perception of fairness. Information transparency and explanations for evaluation outcomes were also examined as potential moderators.ResultsStudy 1 found that different evaluators could significantly influence the perception of fairness under three evaluation contexts. Students perceived AI algorithms as fairer evaluators than teachers. Study 2 revealed that information transparency was a mediator, indicating that students perceived higher fairness with AI algorithms due to increased transparency compared with teachers. Study 3 revealed that the explanation of evaluation outcomes moderated the effect of evaluator on students’ perception of fairness. Specifically, when provided with explanations for evaluation results, the effect of evaluator on students’ perception of fairness was lessened.DiscussionThis study emphasizes the importance of information transparency and comprehensive explanations in the evaluation process, which is more crucial than solely focusing on the type of evaluators. It also draws attention to potential risks like algorithmic hegemony and advocates for ethical considerations, including privacy regulations, in integrating new technologies into educational evaluation systems. Overall, this study provides valuable theoretical insights and practical guidance for conducting fairer educational evaluations in the era of new technologies