Critical Role of Methylammonium Librational Motion in Methylammonium Lead Iodide (CH3NH3PbI3) Perovskite Photochemistry.

Raman and photoluminescence (PL) spectroscopy are used to investigate dynamic structure-function relationships in methylammonium lead iodide (MAPbI3) perovskite. The intensity of the 150 cm-1 methylammonium (MA) librational Raman mode is found to be correlated with PL intensities in microstructures of MAPbI3. Because of the strong hydrogen bond between hydrogens in MA and iodine in the PbI6 perovskite octahedra, the Raman activity of MA is very sensitive to structural distortions of the inorganic framework. The structural distortions directly influence PL intensities, which in turn have been correlated with microstructure quality. Our measurements, supported with first-principles calculations, indicate how excited-state MA librational displacements mechanistically control PL efficiency and lifetime in MAPbI3-material parameters that are likely important for efficient photovoltaic devices

Continued Value Creation in Crowdsourcing from Creative Process Engagement

Purpose Crowdsourcing delivers creative ideas for the issuing firm, but participants’ engagement in the creative process also creates additional benefits to firms and participating customers. To investigate if these spill-over values endure over time, this study uses data from two time points, i.e. at submission and after announcement of the contest winners, to investigate the relationship between the degree of a participant’s creative process engagement (CPE) and value creation from a crowdsourcing contest, and how these perceptions of value change over time. Design/methodology/approach Data was collected from 154 participants in a crowdsourcing contest at two time points with an online survey: at submission, and after receiving feedback (in term of rankings, rewards, and comments) from the community. Partial Least Square (PLS) path modelling was used to estimate both main and moderating effects. Findings CPE increases the perceived value of customers (social and epistemic value) and firms alike (knowledge-sharing intention and customer loyalty), though all but epistemic value decrease over time. Disconfirmation of expectations and need for recognition moderate these effects. Originality/value This paper is the first longitudinal study that helps understanding the effect of CPE on value creation from crowdsourcing across time. It also uses the theoretical lens of the honeymoon hangover effect to explain how perceived value changes. The resulting insights into the role of customer engagement in crowdsourcing contests and subsequent value creation will be beneficial to the growing research stream on consumer value co-creation and user innovation

A Hierarchical Model of Virtual Experience and Its Influences on the Perceived Value and Loyalty of Customers

Many businesses use virtual experience (VE) to enhance the overall customer experience, though extant research offers little guidance for how to improve consumers’ VE. This study, anchored in activity theory, examines key drivers of VE and its influences on value perceptions and customer loyalty. A hierarchical model indicates that VE comprises second-order variables (i.e., social presence, social capital, flow experience, and situational involvement) and third-order variables (i.e., communal and individual experience). The results obtained from a substantive model further reveal that VE positively influences perceptions of both economic and social value and thus influences loyalty in both the real world and virtual environments

Importance of electronic self-consistency in the TDDFT based treatment of nonadiabatic molecular dynamics

A mixed quantum-classical approach to simulate the coupled dynamics of electrons and nuclei in nanoscale molecular systems is presented. The method relies on a second order expansion of the Lagrangian in time-dependent density functional theory (TDDFT) around a suitable reference density. We show that the inclusion of the second order term renders the method a self-consistent scheme and improves the calculated optical spectra of molecules by a proper treatment of the coupled response. In the application to ion-fullerene collisions, the inclusion of self-consistency is found to be crucial for a correct description of the charge transfer between projectile and target. For a model of the photoreceptor in retinal proteins, nonadiabatic molecular dynamics simulations are performed and reveal problems of TDDFT in the prediction of intra-molecular charge transfer excitations.Comment: 9 pages, 8 figures. Minor changes in content wrt older versio

The Cognitive Perception of a Multi-room Music System with Spatial Interaction

Abstract. In recent years we have seen a growing interest in exploring spatial interaction as a means of interacting with computer systems through what has been labelled “proxemic interaction”. In order to explore the potentials and challenges of spatial interaction spanning across separate physical locations, we have developed a multi-room music system and performed a field evaluation of use. The system extends Apple AirPlay to allow spatial interaction with one’s music player, for example, adapting an App interface to the current location of the user, and allowing music to follow the user around the house. The prototype was deployed in two households over a three-week period, where data was col-lected through logging, user-written diaries and interviews. The field evaluation revealed a number of findings related to the cognitive perception of the spaces it was used in, such as importance of a simple interaction, the importance of providing local interaction, the challenge of foreground and background inter-actions, and challenges in designing interaction with music in discrete zones

Infrared spectroscopy of phytochrome and model pigments

Fourier-transform infrared difference spectra between the red-absorbing and far-red-absorbing forms of oat phytochrome have been measured in H2O and 2H2O. The difference spectra are compared with infrared spectra of model compounds, i.e. the (5Z,10Z,15Z)- and (5Z,10Z,15E)-isomers of 2,3,7,8,12,13,17,18-octaethyl-bilindion (Et8-bilindion), 2,3-dihydro-2,3,7,8,12,13,17,18-octaethyl-bilindion (H2Et8-bilindion), and protonated H2Et8-bilindion in various solvents. The spectra of the model compounds show that only for the protonated forms can clear differences between the two isomers be detected. Since considerable differences are present between the spectra of Et8-bilindion and H2Et8-bilindion, it is concluded that only the latter compound can serve as a model system of phytochrome. The 2H2O effect on the difference spectrum of phytochrome supports the view that the chromophore in red-absorbing phytochrome is protonated and suggests, in addition, that it is also protonated in far-red-absorbing phytochrome. The spectra show that protonated carboxyl groups are influenced. The small amplitudes in the difference spectra exclude major changes of protein secondary structure

Reflexos pós-pandêmicos na vida escolar

O período de pandemia foi um tempo de incerteza que deixou profundas cicatrizes emocionais e trouxe prejuízos de toda ordem, dentre eles à aprendizagem. Em razão disso, uma grande inquietação com o retorno às aulas presenciais nas escolas consistiu em saber como lidar com as fragilidades emocionais de professores, alunos e famílias. Além disso, foi fundamental mensurar as consequências que o tempo de isolamento provocou no desenvolvimento das crianças e adolescentes, para poder colocar todos na mesma sintonia. Junto a esse contexto complexo, a escola deveria aprimorar o processo de inclusão, cuja demanda tem aumentado significativamente, o auxílio na regulação emocional do indivíduo e nas resoluções de conflitos com o outro e consigo mesmo. [...