TY - JOUR A1 - Moreno, Eduardo A1 - Großmann, Robert A1 - Beta, Carsten A1 - Alonso, Sergio T1 - From single to collective motion of social amoebae BT - a computational study of interacting cells JF - Frontiers in physics N2 - The coupling of the internal mechanisms of cell polarization to cell shape deformations and subsequent cell crawling poses many interdisciplinary scientific challenges. Several mathematical approaches have been proposed to model the coupling of both processes, where one of the most successful methods relies on a phase field that encodes the morphology of the cell, together with the integration of partial differential equations that account for the polarization mechanism inside the cell domain as defined by the phase field. This approach has been previously employed to model the motion of single cells of the social amoeba Dictyostelium discoideum, a widely used model organism to study actin-driven motility and chemotaxis of eukaryotic cells. Besides single cell motility, Dictyostelium discoideum is also well-known for its collective behavior. Here, we extend the previously introduced model for single cell motility to describe the collective motion of large populations of interacting amoebae by including repulsive interactions between the cells. We performed numerical simulations of this model, first characterizing the motion of single cells in terms of their polarity and velocity vectors. We then systematically studied the collisions between two cells that provided the basic interaction scenarios also observed in larger ensembles of interacting amoebae. Finally, the relevance of the cell density was analyzed, revealing a systematic decrease of the motility with density, associated with the formation of transient cell clusters that emerge in this system even though our model does not include any attractive interactions between cells. This model is a prototypical active matter system for the investigation of the emergent collective dynamics of deformable, self-driven cells with a highly complex, nonlinear coupling of cell shape deformations, self-propulsion and repulsive cell-cell interactions. Understanding these self-organization processes of cells like their autonomous aggregation is of high relevance as collective amoeboid motility is part of wound healing, embryonic morphogenesis or pathological processes like the spreading of metastatic cancer cells. KW - cell motility KW - cell polarity KW - reaction-diffusion models KW - cell-cell KW - interactions KW - phase field model KW - collective motion KW - active matter Y1 - 2022 U6 - https://doi.org/10.3389/fphy.2021.750187 SN - 2296-424X VL - 9 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Kranjc Horvat, Anja A1 - Wiener, Jeff A1 - Schmeling, Sascha A1 - Borowski, Andreas T1 - Learning goals of professional development programs at science research institutions BT - a Delphi study with different stakeholder groups JF - Journal of science teacher education : the official journal of the Association for the Education of Teachers in Science N2 - Effective professional development programs (PDPs) rely on well-defined goals. However, recent studies on PDPs have not explored the goals from a multi-stakeholder perspective. This study identifies the most important learning goals of PDPs at science research institutions as perceived by four groups of stakeholders, namely teachers, education researchers, government representatives, and research scientists. Altogether, over 100 stakeholders from 42 countries involved in PDPs at science research institutions in Europe and North America participated in a three-round Delphi study. In the first round, the stakeholders provided their opinions on what they thought the learning goals of PDPs should be through an open-ended questionnaire. In the second and third rounds, the stakeholders assessed the importance of the learning goals that emerged from the first round by rating and ranking them, respectively. The outcome of the study is a hierarchical list of the ten most important learning goals of PDPs at particle physics laboratories. The stakeholders identified enhancing teachers' knowledge of scientific concepts and models and enhancing their knowledge of the curricula as the most important learning goals. Furthermore, the results show strong agreement between all the stakeholder groups regarding the defined learning goals. Indeed, all groups ranked the learning goals by their perceived importance almost identically. These outcomes could help policymakers establish more specific policies for PDPs. Additionally, they provide PDP practitioners at science research institutions with a solid base for future research and planning endeavors. KW - Teacher professional development KW - Delphi study KW - multi-stakeholder KW - analysis KW - pedagogical content knowledge Y1 - 2021 U6 - https://doi.org/10.1080/1046560X.2021.1905330 SN - 1046-560X SN - 1573-1847 VL - 33 IS - 1 SP - 32 EP - 54 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Fruhstorfer, Anna A1 - Hudson, Alexander T1 - Majorities for minorities BT - Participatory constitution making and the protection of minority rights JF - Political research quarterly : PRQ ; official journal of Western Political Science Association, Pacific Northwest Political Science Association, Southern California Political Science Association, Northern California Political Science Association N2 - Does the process of making a constitution affect the expansiveness of rights protections in the constitution? In particular, is more participation in constitution-making processes better for minority rights protections? While the process of constitution making and its impact on various outcomes have received significant attention, little is known about the impact public participation or deliberation in this process has on the scope and content of minority rights. Using a wide variety of data to empirically assess the relationship between constitution-making processes and the protection of rights for minorities, we find a positive relationship between participatory drafting processes and the inclusion of minority protections in constitutions under some conditions. The article's findings have important implications for understanding political representation and lend support to core arguments about the role of the public in constitutional design. KW - constitution-making KW - human rights KW - minority rights KW - direct democracy KW - public participation Y1 - 2022 U6 - https://doi.org/10.1177/1065912920984246 SN - 1065-9129 SN - 1938-274X VL - 75 IS - 1 SP - 103 EP - 117 PB - Sage Publ. CY - Thousand Oaks ER - TY - JOUR A1 - Mtilatila, Lucy Mphatso Ng'ombe A1 - Bronstert, Axel A1 - Vormoor, Klaus Josef T1 - Temporal evaluation and projections of meteorological droughts in the Greater Lake Malawi Basin, Southeast Africa JF - Frontiers in water N2 - The study examined the potential future changes of drought characteristics in the Greater Lake Malawi Basin in Southeast Africa. This region strongly depends on water resources to generate electricity and food. Future projections (considering both moderate and high emission scenarios) of temperature and precipitation from an ensemble of 16 bias-corrected climate model combinations were blended with a scenario-neutral response surface approach to analyses changes in: (i) the meteorological conditions, (ii) the meteorological water balance, and (iii) selected drought characteristics such as drought intensity, drought months, and drought events, which were derived from the Standardized Precipitation and Evapotranspiration Index. Changes were analyzed for a near-term (2021-2050) and far-term period (2071-2100) with reference to 1976-2005. The effect of bias-correction (i.e., empirical quantile mapping) on the ability of the climate model ensemble to reproduce observed drought characteristics as compared to raw climate projections was also investigated. Results suggest that the bias-correction improves the climate models in terms of reproducing temperature and precipitation statistics but not drought characteristics. Still, despite the differences in the internal structures and uncertainties that exist among the climate models, they all agree on an increase of meteorological droughts in the future in terms of higher drought intensity and longer events. Drought intensity is projected to increase between +25 and +50% during 2021-2050 and between +131 and +388% during 2071-2100. This translates into +3 to +5, and +7 to +8 more drought months per year during both periods, respectively. With longer lasting drought events, the number of drought events decreases. Projected droughts based on the high emission scenario are 1.7 times more severe than droughts based on the moderate scenario. That means that droughts in this region will likely become more severe in the coming decades. Despite the inherent high uncertainties of climate projections, the results provide a basis in planning and (water-)managing activities for climate change adaptation measures in Malawi. This is of particular relevance for water management issues referring hydro power generation and food production, both for rain-fed and irrigated agriculture. KW - meteorological drought KW - drought intensity KW - climate change KW - drought KW - events KW - Lake Malawi KW - Shire River KW - drought projections KW - South-Eastern KW - Africa Y1 - 2022 U6 - https://doi.org/10.3389/frwa.2022.1041452 SN - 2624-9375 VL - 4 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Aral, Tuğçe A1 - Schachner, Maja K. A1 - Juang, Linda P. A1 - Schwarzenthal, Miriam T1 - Cultural diversity approaches in schools and adolescents’ willingness to support refugee youth JF - British journal of educational psychology / British Psychological Society N2 - Background Culturally diverse schools contribute to adolescents' intergroup relations. Complex and inclusive social identities are mechanisms that can explain the link between structural school cultural diversity (i.e., proportion of students of immigrant descent and the number of different ethnic groups) and positive intergroup relations. We expected that similar mechanisms might be at play linking cultural diversity approaches in schools with adolescents' intergroup relations. Aim We examined the link between two sub-dimensions of cultural diversity approaches (i.e., equal treatment; heritage and intercultural learning) and adolescents' prosocial intentions and behaviour towards refugee youth. Then, we explored the mediating role of identity inclusiveness (i.e., perceived similarity of the self with others). Sample and methods We sampled culturally diverse eighth grade adolescents from 54 classrooms in Berlin (N = 503, M-age = 13.76 years, 50.6% female). Surveys measured perceived cultural diversity norms, adolescents' perceived identity inclusiveness with refugee youth, prosocial intentions to support refugee youth, and willingness to donate to a project for refugee youth. Results Multilevel models revealed that adolescents' perception of heritage and intercultural learning predicted adolescents' prosocial intentions towards refugee youth, but not their willingness to donate. Equal treatment was not a significant predictor of adolescents' prosocial intentions towards refugee youth, or their willingness to donate. Identity inclusiveness did not mediate the relation between cultural diversity approaches and prosocial intentions. However, identity inclusiveness did positively relate adolescents' prosocial intentions and willingness to donate. Conclusions We conclude that culturally diverse schools that engage in heritage and intercultural learning might help to promote positive relations between local and refugee youth in schools and society. Fostering inclusive identities may enhance local adolescent's prosocial intention and behaviour. KW - equal treatment KW - heritage and intercultural learning KW - prosocial KW - intentions KW - prosocial behaviour KW - identity inclusiveness KW - refugee youth Y1 - 2021 U6 - https://doi.org/10.1111/bjep.12458 SN - 0007-0998 SN - 2044-8279 VL - 92 IS - 2 SP - 772 EP - 799 PB - Wiley-Blackwell CY - Oxford ER - TY - JOUR A1 - Spiekermann, Sarah A1 - Krasnova, Hanna A1 - Hinz, Oliver A1 - Baumann, Annika A1 - Benlian, Alexander A1 - Gimpel, Henner A1 - Heimbach, Irina A1 - Koester, Antonia A1 - Maedche, Alexander A1 - Niehaves, Bjoern A1 - Risius, Marten A1 - Trenz, Manuel T1 - Values and ethics in information systems BT - a state-of-the-art analysis and avenues for future research JF - Business & information systems engineering Y1 - 2022 U6 - https://doi.org/10.1007/s12599-021-00734-8 SN - 2363-7005 SN - 1867-0202 VL - 64 IS - 2 SP - 247 EP - 264 PB - Springer Gabler CY - Wiesbaden ER - TY - JOUR A1 - Krause, Hannes-Vincent A1 - Große Deters, Fenne A1 - Baumann, Annika A1 - Krasnova, Hanna T1 - Active social media use and its impact on well-being BT - an experimental study on the effects of posting pictures on Instagram JF - Journal of computer-mediated communication : a journal of the International Communication Association N2 - Active use of social networking sites (SNSs) has long been assumed to benefit users' well-being. However, this established hypothesis is increasingly being challenged, with scholars criticizing its lack of empirical support and the imprecise conceptualization of active use. Nevertheless, with considerable heterogeneity among existing studies on the hypothesis and causal evidence still limited, a final verdict on its robustness is still pending. To contribute to this ongoing debate, we conducted a week-long randomized control trial with N = 381 adult Instagram users recruited via Prolific. Specifically, we tested how active SNS use, operationalized as picture postings on Instagram, affects different dimensions of well-being. The results depicted a positive effect on users' positive affect but null findings for other well-being outcomes. The findings broadly align with the recent criticism against the active use hypothesis and support the call for a more nuanced view on the impact of SNSs.
Lay Summary Active use of social networking sites (SNSs) has long been assumed to benefit users' well-being. However, this established assumption is increasingly being challenged, with scholars criticizing its lack of empirical support and the imprecise conceptualization of active use. Nevertheless, with great diversity among conducted studies on the hypothesis and a lack of causal evidence, a final verdict on its viability is still pending. To contribute to this ongoing debate, we conducted a week-long experimental investigation with 381 adult Instagram users. Specifically, we tested how posting pictures on Instagram affects different aspects of well-being. The results of this study depicted a positive effect of posting Instagram pictures on users' experienced positive emotions but no effects on other aspects of well-being. The findings broadly align with the recent criticism against the active use hypothesis and support the call for a more nuanced view on the impact of SNSs on users. KW - social networking sites KW - social media KW - Instagram KW - well-being KW - experiment KW - randomized control trial Y1 - 2022 U6 - https://doi.org/10.1093/jcmc/zmac037 SN - 1083-6101 VL - 28 IS - 1 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Vinod, Deepak A1 - Cherstvy, Andrey G. A1 - Metzler, Ralf A1 - Sokolov, Igor M. T1 - Time-averaging and nonergodicity of reset geometric Brownian motion with drift JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - How do near-bankruptcy events in the past affect the dynamics of stock-market prices in the future? Specifically, what are the long-time properties of a time-local exponential growth of stock-market prices under the influence of stochastically occurring economic crashes? Here, we derive the ensemble- and time-averaged properties of the respective "economic" or geometric Brownian motion (GBM) with a nonzero drift exposed to a Poissonian constant-rate price-restarting process of "resetting." We examine-based both on thorough analytical calculations and on findings from systematic stochastic computer simulations-the general situation of reset GBM with a nonzero [positive] drift and for all special cases emerging for varying parameters of drift, volatility, and reset rate in the model. We derive and summarize all short- and long-time dependencies for the mean-squared displacement (MSD), the variance, and the mean time-averaged MSD (TAMSD) of the process of Poisson-reset GBM under the conditions of both rare and frequent resetting. We consider three main regions of model parameters and categorize the crossovers between different functional behaviors of the statistical quantifiers of this process. The analytical relations are fully supported by the results of computer simulations. In particular, we obtain that Poisson-reset GBM is a nonergodic stochastic process, with generally MSD(Delta) not equal TAMSD(Delta) and Variance(Delta) not equal TAMSD(Delta) at short lag times Delta and for long trajectory lengths T. We investigate the behavior of the ergodicity-breaking parameter in each of the three regions of parameters and examine its dependence on the rate of reset at Delta/T << 1. Applications of these theoretical results to the analysis of prices of reset-containing options are pertinent. Y1 - 2022 U6 - https://doi.org/10.1103/PhysRevE.106.034137 SN - 2470-0045 SN - 2470-0053 VL - 106 IS - 3 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Czakon, Wojciech A1 - Klimas, Patrycja A1 - Tiberius, Victor A1 - Ferreira, João A1 - Veiga, Pedro M. A1 - Kraus, Sascha T1 - Entrepreneurial failure BT - structuring a widely overlooked field of research JF - Entrepreneurship research journal N2 - Although entrepreneurial failure (EF) is a fairly recent topic in entrepreneurship literature, the number of publications has been growing dynamically and particularly rapidly. Our systematic review maps and integrates the research on EF based on a multi-method approach to give structure and consistency to this fragmented field of research. The results reveal that the field revolves around six thematic clusters of EF: 1) Soft underpinnings of EF, 2) Contextuality of EF, 3) Perception of EF, 4) Two-sided effects of EF, 5) Multi-stage EF effects, and 6) Institutional drivers of EF. An integrative framework of the positive and negative effects of entrepreneurial failure is proposed, and a research agenda is suggested. KW - entrepreneurial failure KW - entrepreneurship KW - failure outcomes KW - systematic review Y1 - 2022 U6 - https://doi.org/10.1515/erj-2021-0328 SN - 2157-5665 SP - 1 EP - 34 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Sandberg, Helene A1 - Alnoor, Alhamzah A1 - Tiberius, Victor T1 - Environmental, social, and governance ratings and financial performance BT - evidence from the European food industry JF - Business strategy and the environment N2 - Long-term value creation is expected not only to be concerned with maximizing shareholder value but also includes the impact on other stakeholders and the environment. Environmental, social, and governance (ESG) issues are therefore gaining increasing importance, in line with the growing demand for corporate sustainability. ESG ratings foster the comparison of companies with respect to their sustainable practices. This study aims to investigate how ESG ratings impact financial performance in the European food industry. Ordinary least squares regression is applied to analyze the relation between ESG ratings and financial performance over a 4-year period from 2017 to 2020. The profitability measures Return on Assets (ROA) and Return on Equity (ROE) are employed as financial performance measures, while ESG ratings are obtained from the database CSRHub. Results show that higher ESG ratings are associated with better financial performance. Although the effect is modest in the present study, the findings support previous results that ESG ratings are positively related to financial performance. Nonetheless, they also highlight that ESG ratings strongly converge to the mean, which depicts the need to reassess whether ESG ratings are able to measure actual ESG behavior. KW - ESG ratings KW - firm performance KW - food industry Y1 - 2022 U6 - https://doi.org/10.1002/bse.3259 SN - 0964-4733 SN - 1099-0836 VL - 32 IS - 4 SP - 2471 EP - 2489 PB - Wiley CY - New York ER -