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Based on a theoretical perspective of the optimum stimulation level (OSL), we investigate how the cross-media usage (multi-device and multi-app usage) of individual users influences their exploration of new music in a music-streaming platform. We also examine whether gender moderates the link between cross-media usage and new music exploration behavior. We analyze survey responses from 1116 college students in China, and our findings show a significant and positive effect of multi-device usage on new music exploration. By contrast, multi-app usage does not have any statistically significant effect. The results also indicate that being a woman positively moderates the relationship between multi-app usage and new music exploration behavior. Our study contributes to the understanding of exploratory user behavior in a new media context by linking the OSL theory to digital music consumption. [ABSTRACT FROM AUTHOR]

During the pandemic era, COVID-related disclosure has become quite critical for shareholders and other market participants to understand the uncertainties and challenges associated with a firm's operation. However, there is no well-grounded and systematic measure to gauge the intensity of COVID-related disclosure and its plausible impact. Therefore, this study develops and validates various COVID-related disclosure measures. More specifically, using a sample of publicly listed U.S. firms and applying natural language processing (NLP) on 10-K reports, we have developed two types of COVID dictionaries (or COVID-related disclosure measurement tools): (a) overall COVID dictionary (count of all COVID-related words/phrases) and (b) contextual COVID-dictionary (count of COVID related words/phrases preceded or followed by positive, negative tones, or financial constraints words). Subsequently, we have validated both types of COVID dictionaries by investigating their association with corporate liquidity events (e.g., dividend payment, dividend change). We confirm that the overall COVID dictionary effectively predicts a firm's liquidity event. We find similar results for contextual COVID dictionaries with a negative spin (i.e., COVID disclosures with a negative tone or an indication of financial constraints). Our results further show that better-governed firms (e.g., greater board independence, and more female directors) tend to have more COVID-related disclosures, despite the fact that more COVID-related disclosures suppress a firm's market-based stock performance (e.g. Tobin's Q). Our results suggest that better-governed firms prefer greater transparency, even if it may hurt their market performance in the short run. [ABSTRACT FROM AUTHOR]

Numerical simulation of magnetohydrodynamic natural convection heat transfer in a rhombic enclosure of inclination angle 45 ∘ containing copper-water nanofluid has been presented in this paper. The top and bottom walls of the enclosure are subjected to non-uniform heating while left wall being subjected to lower temperature and right wall being maintained adiabatic. The finite element strategy (COMSOL Multiphysics) is used to solve the governing equations. The numerical simulations are done for the parametric values: 10 4 ≤ Rayleigh number ≤ 10 6 ; 0 ≤ Hartmann number ≤ 100; 0 ≤ volume fraction of nanofluid ≤ 0.05. The phase deviation angle (top wall) is varied in the range from 0 to π with amplitude of non linear heating being maintained constant. The motivation of this research goes with the fact that the associated transport phenomenon conveys the implication of designing an optimal thermal system analogous to the theme of non-uniform heating, with the phase angle being a crucial design parameter. The numerical results depict to the fact, that the rate of heat transfer follows non-monotonic trends and is considerably influenced by interplay of the phase shift angle, Rayleigh number and Hartmann number. The results showed that at Rayleigh number ≥ 10 5 , the heat transfer rate gets inhibited by enhancing the magnetic field intensity. The impact of different types of nano particles is illustrated by comparing the results with the results of three different nanofluids, silver– water, titanium dioxide–water and diamond–water nanofluids. [ABSTRACT FROM AUTHOR]

In this study, we use an effective word embedding model (word2vec) to systematically track 'vaccine hesitancy' and 'logistical challenges' associated with the Covid-19 vaccines, in the USA. To that effect, we use news articles from reputed media sources and create dictionaries to estimate different aspects of vaccine hesitancy and logistical challenges. Using machine learning and natural language processing techniques, we have developed (i) three sub-dictionaries that indicate vaccine hesitancy, and (ii) another dictionary for logistical challenges associated with vaccine production and distribution. Vaccine hesitancy dictionaries capture three aspects: (a) general vaccine related concerns, mistrusts, skepticisms, and hesitancy, (b) discussions on symptoms and side-effects, and (c) discussions on vaccine related physical effects. The dictionary on logistical challenges includes the words and phrases related to the production, storage, and distribution of vaccines. Our results show that over time, as vaccine developers complete different phase trials and get approval for their respective vaccines, the number of vaccine related news articles increases sharply. Accordingly, we also see a sharp increase in vaccine hesitancy related topics in news articles. However, in January 2021, there has been a decrease in the vaccine hesitancy score, which will give some relief to the health administrators and regulators. Our findings further show that as we get closer to the breakthrough of effective Covid-19 vaccines, new logistical challenges continue to rise, even in recent months. [ABSTRACT FROM AUTHOR]

In this paper, we present a numerical investigation of natural convection heat transfer and entropy generation for a rhombic enclosure with inclination angle, ϕ = 30°, filled with a porous medium. The left and right surface walls of the enclosure are confined to cold temperature bath while we impart non-uniform, varying temperature distribution with unequal phase angles along the top and bottom wall. The flow inside the enclosure is steady, two-dimensional, incompressible and laminar, and the working fluid is air (Pr = 0.71). Numerical experiments have been performed using finite element method-based software COMSOL Multiphysics 5a for Darcy number and Rayleigh number in the extent of 10−4–10−2 and 103–106, respectively, in addition to phase deviation angles varying in the range from 0 to π. The amplitude parameter associated with the temperature delineation of the bottom and top walls is kept constant. The realizations from the numerical investigation are exhibited by streamlines and isotherms, local and average heat transfer Nusselt number along with the local distribution of heat transfer and fluid friction irreversibilities. The rate of heat transfer demonstrates non-monotonic trends and can be considerably influenced by the interplay of the phase shift angle, Rayleigh number and Darcy number. Upon increasing the value of phase shift angle from 0 to π, average Nusselt number initially decreases and thereafter shows an increase in its value. As the Darcy number increases, average Nusselt number for the bottom wall increases, while for the top wall it strongly depends on phase shift angle. In terms of entropy generation, it is found that the significant contributor to irreversibility is induced by heat transfer and the location of maximum entropy varies with the change in phase angle. More specifically, minimum entropy generation for any value of Rayleigh number and Darcy number is obtained for a phase shift angle of π/4 and maximum for 3π/4. The concomitant transport characteristics bear significance from the context of design of thermal systems pertaining to the theme of non-uniform heating with the phase angle being a crucial design parameter. [ABSTRACT FROM AUTHOR]

With increase in lifestyle diseases such as diabetes, hypertension and heart disease in emerging economies, it is important to understand the impact of acquiring these health issues on household income and consumption. Using a panel data of Indian households, we show that acquiring diabetes, hypertension or heart disease results in increased medical and non-medical expenses for high-income households. However, affected low-income households, to meet their increased medical expenses, had to divert resources from non-medical expenses. Our findings add to the extant marketing literature on impact of crises on consumption behaviour and the marketing implications of such changes in consumption behaviour. [ABSTRACT FROM AUTHOR]

A numerical study of fluid flow and heat transfer, applying natural convection is carried out in a porous corrugated rhombic enclosure. A uniform heating source is applied from the bottom boundary wall while the inclined side walls are maintained to a constant cold temperature and the top corrugated wall is retained at insulated condition inside the enclosure. The heat transfer and flow features are presented for a wide spectrum of Rayleigh numbers (Ra), 104 ≤ Ra ≤ 106 , and Darcy numbers (Da), 10-3 ≤ Da ≤ 10-2 . The number of undulations (n) for the top and bottom walls have been varied from 1 to 13 keeping the amplitude of undulation fixed. It is revealed that the characteristics of heat transfer are conceivably modulated by changing the parameter of the undulation number on the enclosure walls, specifically at the bottom and top. The influencing control of n in altering the heat transfer rate is felt maximum on the left wall and minimum for the right wall, and there is a strong interplay between Ra and Da together with n on dictating the heat transfer characteristics. The critical value, where heat transfer rate is observed as maximum is at n = 11 and thereafter the values decrease. [ABSTRACT FROM AUTHOR]

Highlights • MHD natural convection inside a rhombic enclosure filled with nanofluid is studied. • Effect of Rayleigh number, Hartmann number and inclination angles of the enclosure are examined. • The presence of the magnetic field is more perceptible in dictating Nu at higher Ra. • Operating zone of Ra depicting the negative efficacy of nanofluid is presented. • Entropy generation decreases with increase in both Ha and inclination angle. Abstract The present work analyses magnetohydrodynamic natural convection heat transfer and entropy generation in rhombic enclosures filled with Cu-water nanofluids. Numerical simulations were executed for varying Rayleigh number (Ra) in the range 103–106, Hartmann number (Ha) in the range 0–100 and inclination angles of the enclosure (30°, 45° and 60°) considering three different volume fractions of the nanofluid (1%, 3% and 5%). The results indicate that at low Ra , the heat transfer rate remains invariant with the variation in Ha. At high Ra (≥105), the presence of the magnetic field is more perceptible implying that the reduction in heat transfer rate with the increase in magnetic field intensity is far more significant. The heat transfer rate enhances with the increase in inclination angle for all Ha for Ra =103 and 104. However, at high Ra (=105 and 106) the trend becomes contrasting due to the interplay of buoyancy and Lorentz forces. There exists an operating range of Ha in the convection regime wherein the efficacy of the nanofluid in augmenting the heat transfer rate is negated when compared to the corresponding performance of the base fluid. The concomitant thermal identity resulting due to the combined interactions of Hartmann number and volume fraction of the nanofluid have been presented. The entropy generation rate decreases with the increase in Ha for all values of Ra and inclination angles of the enclosure. [ABSTRACT FROM AUTHOR]

In this work, we study numerically the natural convection heat transfer and entropy generation characteristics inside a two-dimensional porous quadrantal enclosure heated nonuniformly from the bottom wall. The effect of Darcy number is significant in dictating the Nusselt number only for higher values of Rayleigh number and the variation is more profound for larger values of Darcy number. The variation of entropy generation rate is significant with the Darcy number only for higher values of Rayleigh number. The entropy generation due to heat transfer is the significant contributor of irreversibility at low values of Darcy number, while for larger values of Darcy number and Rayleigh number entropy generation due to fluid friction becomes dominant. [ABSTRACT FROM AUTHOR]

Financial restatements have been a major concern for the regulators, investors and market participants. Most of the previous studies focus only on fraudulent (or intentional) restatements and the literature has largely ignored unintentional restatements. Earlier studies have shown that large scale unintentional restatements can be equally detrimental and may erode investors’ confidence. Therefore it is important for us to pay a close to the significant unintentional restatements as well. A lack of focus on unintentional restatements could lead to a more relaxed internal control environment and lessen the efforts for curbing managerial oversights and instances of misreporting. In order to address this research gap, we focus on developing predictive models based on both intentional (fraudulent) and unintentional (erroneous) financial restatements using a comprehensive real dataset that includes 3,513 restatement cases over a period of 2001 to 2014. To the best of our knowledge it is the most comprehensive dataset used in the financial restatement predictive models. Our study also makes contributions to the datamining literature by (i) focussing on various datamining techniques and presenting a comparative analysis, (ii) ensuring the robustness of various predictive models over different time periods. We have employed all widely used data mining techniques in this area, namely, Decision Tree (DT), Artificial Neural Network (ANN), Naïve Bayes (NB), Support Vector Machine (SVM), and Bayesian Belief Network (BBN) Classifier while developing the predictive models. We find that ANN outperforms other data mining algorithms in our empirical setup in terms of accuracy and area under the ROC curve. It is worth noting that our models remain consistent over the full sample period (2001-2014), pre-financial-crisis period (2001-2008), and post-financial-crisis period (2009-2014). We believe this study will benefit academics, regulators, policymakers and investors. In particular, regulators and policymakers can pay a close attention to the suspected firms and investors can take actions in advance to reduce their investment risks. The results can also help improving expert and intelligent systems by providing more insights on both intentional and unintentional financial restatements. [ABSTRACT FROM AUTHOR]

We test news media's disciplining by dissemination role and predictive power in insider trading related issues with a large and novel dataset on Chinese firms between 2008 and 2017. We find that more media coverage is associated with significantly lower level of insider trading profitability, which confirms the disciplining by dissemination role of media documented in the developed market. However, as a new evidence to the media and insider trading literature, we also find that media's negative tone has a positive correlation with future insider trading profitability, which is consistent with the media predictive power argument. In addition, we find that media's predictive power is amplified by a firm's good governance structure and low level of information asymmetry. Our study shows news media's effectiveness in predicting opportunistic insider trading in China. [ABSTRACT FROM AUTHOR]

The authors requested that PLOS remove the article from online publication, and informed PLOS that the University of Ottawa library and representatives of Factiva (Dow Jones) had both requested this action. Reference 1 Dutta S, Kumar A, Dutta M, Walsh C (2021) Tracking COVID-19 vaccine hesitancy and logistical challenges: A machine learning approach. While the authors represented to PLOS that they had legitimate permissions to access the articles, concerns were noted post-publication that the authors' data mining of news articles on Factiva did not comply with the terms of the University of Ottawa's license with Factiva. [Extracted from the article]

We develop a constrained extremely zero inflated joint (CEZIJ) modeling framework for simultaneously analyzing player activity, engagement, and dropouts (churns) in app-based mobile freemium games. Our proposed framework addresses the complex interdependencies between a player's decision to use a freemium product, the extent of her direct and indirect engagement with the product and her decision to permanently drop its usage. CEZIJ extends the existing class of joint models for longitudinal and survival data in several ways. It not only accommodates extremely zero-inflated responses in a joint model setting but also incorporates domain-specific, convex structural constraints on the model parameters. Longitudinal data from app-based mobile games usually exhibit a large set of potential predictors and choosing the relevant set of predictors is highly desirable for various purposes including improved predictability. To achieve this goal, CEZIJ conducts simultaneous, coordinated selection of fixed and random effects in high-dimensional penalized generalized linear mixed models. For analyzing such large-scale datasets, variable selection and estimation are conducted via a distributed computing based split-and-conquer approach that massively increases scalability and provides better predictive performance over competing predictive methods. Our results reveal codependencies between varied player characteristics that promote player activity and engagement. Furthermore, the predicted churn probabilities exhibit idiosyncratic clusters of player profiles over time based on which marketers and game managers can segment the playing population for improved monetization of app-based freemium games. for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement. [ABSTRACT FROM AUTHOR]

Abstract: This article provides empirical tests of the hypothesis of ‘optimal cognitive distance’, proposed by Nooteboom [Nooteboom, B., 1998. Cost, quality and learning based governance of buyer–supplier relations. In: Colombo, M.G. (Ed.), The Changing Boundaries of the Firm. Routledge, London, pp. 187–208; Nooteboom, B., 2000. Learning and Innovation in Organizations and Economies. Oxford University Press, Oxford], in two distinct empirical settings. Variety of cognition, needed for learning, has two dimensions: the number of agents with different cognition, and differences in cognition between them (cognitive distance). The hypothesis is that in interfirm relationships optimal learning entails a trade-off between the advantage of increased cognitive distance for a higher novelty value of a partner''s knowledge, and the disadvantage of less mutual understanding. If the value of learning is the mathematical product of novelty value and understandability, it has an inverse U-shaped relation with cognitive distance, with an optimum level that yields maximal value of learning. With auxiliary hypotheses, the hypothesis is tested on interfirm agreements between pharmaceutical companies and biotech companies, as well as on interfirm agreements in ICT industries. [Copyright &y& Elsevier]

We study the impact of marketplace literacy education on marketplace coping behaviors in the face of systemic shock due to demonetization, deriving important implications for consumer affairs from this radically distinct context. We study whether and how such education can have positive impact even in the face of such macrolevel disruption that disproportionately affects those with the least resources and renders them even more vulnerable. Marketplace literacy education encompasses awareness and knowledge about marketing as well as self‐confidence and awareness of rights as buyers and sellers. We examine the influence of marketplace literacy in urban and rural areas on coping behaviors of low‐income women consumer–entrepreneurs during demonetization in India, using a retrospective survey. We derive implications to mitigate the effect of future shocks on consumers and entrepreneurs at the vulnerable end of the income spectrum. [ABSTRACT FROM AUTHOR]

Abstract: Protection group of amino- and tethered o-arene functionality of 1,4-aryl-2-amino-1-butanol derived from l-serine dictates the cyclization mode under acidic conditions leading to reverse diastereoselectivity. N-Boc and acetal protected amino alcohol undergo cascade cyclization providing exclusively cis-dihydrexidine via reduction, where formation of C-ring (isoquinoline unit) prior to Friedel–Crafts cyclization control the cis-stereochemistry of the B-ring. N-Cbz and O-benzyl protection direct first F–C cyclization yielding the trans-1-aryl-2-aminotetralin and subsequent deprotection-cyclization forming the C-ring afforded dihydrexidine. [Copyright &y& Elsevier]

Abstract: A divergent and scalable asymmetric synthesis of the dopamine D1 agonists, A-86929, and dihydrexidine with high diastereo- and enantioselectivity was accomplished from Weinreb amide 8 derived from inexpensive and easily available l -serine. The synthesis of A-86929 involves only one chromatographic purification. [Copyright &y& Elsevier]

A catalyst-free conjugate addition of indoles and pyrroles to 1,2-dihydro-3-nitronaphthalenes in water has been developed. A variety of indoles containing electron-rich and -deficient functional groups including aza-indoles and pyrroles reacted smoothly with a number of dihydro-3-nitronaphthalenes, especially bromo derivatives. For structural elaboration, the bromo functionality (dihydronitronaphthalene unit as well as indolyl unit) of the addition products was utilized for Suzuki coupling reactions and provided moderate to good yields of the desired coupling compounds. The utility of the method was further demonstrated by the synthesis of 3,4-fused tetrahydro-β-carbolines, a new class of compounds, from the addition products through reduction of the nitro group to the amine and subsequent Pictet-Spengler cyclization. [ABSTRACT FROM AUTHOR]

A highly enantioselective (up to 91% ee) rhodium-catalyzed asymmetric addition of arylboronic acids has been achieved leading to the challenging dihydro-3-nitronaphthalenes using one equivalent of phosphoramidite ligand to rhodium catalyst. A concise formal asymmetric synthesis of the dopamine D1 agonist, dihydrexidine was accomplished using the method. [ABSTRACT FROM AUTHOR]

Abstract: The total synthesis of stevastelin B3 was achieved using, as a key step, a method developed by us for the synthesis of 2-methyl-1,3-diols by Ti(III)-mediated diastereo- and regioselective opening of trisubstituted 2,3-epoxy alcohols, to carry out the stereoselective construction of its propionate-derived fatty acid segment. [Copyright &y& Elsevier]

Prodrugs of dynemicin analogs were synthesized and their activation by aldolase antibody (Ab) 38C2 was evaluated by DNA-cleaving activity, as well as tumor cell growth inhibition. Further, the authors provide evidence that the activated enediynes underwent covalent crosscoupling with the aldolase Ab, which appears to be a limiting factor of their tumor cell growth-inhibiting activity and should be of general interest in the field of enediyne chemotherapy.

For the first time a divergent and scalable synthesis of the dimethyl ethers (II) and (VI) of the title compounds is described starting from L-serine derived materials. [ABSTRACT FROM AUTHOR]