4,395 research outputs found
The Value of Real and Financial Risk Management
We characterize a firm as a nexus of activities and projects with their associated cashflows. Production and operations activities and real risk management activities distribute cashflows over states of nature and time periods, leading to a transformation possibility frontier similar to a production function. The concavity of the frontier induces a firm to react more or less to changes in market prices of risks to attain the new value maximizing portfolio of real activities. Financial risk management helps implement these real project changes and alleviate the related reorganization and coordination problems. Empirically, we show that a firm's reactiveness to variations in risk prices is linked to its hedging activities. We also argue that financial risk management allows a firm to meet cashflow-at-risk or value-at-risk constraints at little or no cost. Nous caractérisons une entreprise comme un ensemble de projets avec les flux monétaires qui y sont associés. Les activités de production et d'exploitation de même que les activités de gestion réelle des risques distribuent ces flux entre divers états de la nature et périodes. Il en résulte une frontière des possibilités de transformation des flux similaire à une frontière de production. La concavité de la frontière amène la firme à réagir plus ou moins aux changements dans les prix des risques pour atteindre le nouveau portefeuille optimal d’activités réelles. La gestion financière des risques aide à implémenter ces modifications dans les projets et allège ainsi les problèmes associés de réorganisation et de coordination. Empiriquement, nous montrons que le degré de réactivité de la firme aux variations des prix des risques influence ses activités de couverture. De plus, nous montrons que la gestion financière des risques permet à l’entreprise de rencontrer des contraintes de cashflow-à -risque ou de valeur-à -risque à peu ou pas de frais.risk management, firm value, hedging, value at risk, gestion des risques, valeur de la firme, coordination, valeur à risque
The seed of goal-related doubts : a longitudinal investigation of the roles of failure and expectation of success among police trainee applicants
Various theories on personal goal striving rely on the assumption that failure raises doubts about the goal. Yet, empirical evidence for an association between objective failure experiences and doubts about personal long-term goals is still missing. In a longitudinal field study, applicants for a job as a police trainee (n = 172, Mage = 25.15; 55 females and 117 males) were accompanied across three measurement times over a period of five months. We investigated the effects of failure and initial expectation of success (in the standardized selection process) on doubts regarding the superordinate goal of becoming a police officer. As hypothesized, both failure and low initial expectation of success as well as their interaction led to increased goal-related doubts over time. The findings provide first empirical evidence for the role of failure in the emergence of goal-related doubts in personal long-term goals and, therefore, the disengagement process as it is hypothesized in various theories on goal striving and life-span development
Crowdbreaks: Tracking Health Trends Using Public Social Media Data and Crowdsourcing
In the past decade, tracking health trends using social media data has shown great promise, due to a powerful combination of massive adoption of social media around the world, and increasingly potent hardware and software that enables us to work with these new big data streams. At the same time, many challenging problems have been identified. First, there is often a mismatch between how rapidly online data can change, and how rapidly algorithms are updated, which means that there is limited reusability for algorithms trained on past data as their performance decreases over time. Second, much of the work is focusing on specific issues during a specific past period in time, even though public health institutions would need flexible tools to assess multiple evolving situations in real time. Third, most tools providing such capabilities are proprietary systems with little algorithmic or data transparency, and thus little buy-in from the global public health and research community. Here, we introduce Crowdbreaks, an open platform which allows tracking of health trends by making use of continuous crowdsourced labeling of public social media content. The system is built in a way which automatizes the typical workflow from data collection, filtering, labeling and training of machine learning classifiers and therefore can greatly accelerate the research process in the public health domain. This work describes the technical aspects of the platform, thereby covering the functionalities at its current state and exploring its future use cases and extensions
Alleviating Coordination Problems and Regulatory Constraints through Financial Risk Management
We characterize a firm as a nexus of activities and projects with their associated cash flow distributions across states of the world and time periods. We propose a characterization of the firm where variations in the market price of risk induce adjustments in the value-maximizing combination of projects. Changing the portfolio of projects generates coordination costs. We propose a new role for financial risk management based on the idea that the use of financial derivatives may reduce coordination costs. We find empirical support for this new rationale for the use of financial derivatives, after controlling for the traditional variables explaining the need for financial risk management. Nous caractérisons une entreprise comme un ensemble d'activités et de projets avec leurs flux financiers par état et période. Nous proposons une caractérisation de l'entreprise où les variations dans le prix de marché du risque induisent des ajustements dans la combinaison optimale d’activités ou de projets. Les modifications du portefeuille de projets génèrent des coûts de coordination. Nous proposons un nouveau rôle pour la gestion financière des risques en proposant que l'utilisation de titres financiers puisse réduire les coûts de coordination. Ce nouveau rôle de la gestion financière des risques est vérifié empiriquement, une fois pris en compte les facteurs explicatifs traditionnels de la gestion financière des risques.Risk Management, firm value, coordination problems, hedging, value at risk., Gestion des risques, valeur d’entreprise, problèmes de coordination, hedging, valeur à risque.
The mycorrhizal symbiosis: research frontiers in genomics, ecology, and agricultural application
Mycorrhizal symbioses between plants and fungi are vital for the soil structure, nutrient cycling, plant diversity, and ecosystem sustainability. More than 250 000 plant species are associated with mycorrhizal fungi. Recent advances in genomics and related approaches have revolutionized our understanding of the biology and ecology of mycorrhizal associations. The genomes of 250+ mycorrhizal fungi have been released and hundreds of genes that play pivotal roles in regulating symbiosis development and metabolism have been characterized. rDNA metabarcoding and metatranscriptomics provide novel insights into the ecological cues driving mycorrhizal communities and functions expressed by these associations, linking genes to ecological traits such as nutrient acquisition and soil organic matter decomposition. Here, we review genomic studies that have revealed genes involved in nutrient uptake and symbiosis development, and discuss adaptations that are fundamental to the evolution of mycorrhizal lifestyles. We also evaluated the ecosystem services provided by mycorrhizal networks and discuss how mycorrhizal symbioses hold promise for sustainable agriculture and forestry by enhancing nutrient acquisition and stress tolerance. Overall, unraveling the intricate dynamics of mycorrhizal symbioses is paramount for promoting ecological sustainability and addressing current pressing environmental concerns. This review ends with major frontiers for further research
Resolution of Conflicting Signals at the Single-Cell Level in the Regulation of Cyanobacterial Photosynthesis and Nitrogen Fixation
Unicellular, diazotrophic cyanobacteria temporally separate dinitrogen (N-2) fixation and photosynthesis to prevent inactivation of the nitrogenase by oxygen. This temporal segregation is regulated by a circadian clock with oscillating activities of N-2 fixation in the dark and photosynthesis in the light. On the population level, this separation is not always complete, since the two processes can overlap during transitions from dark to light. How do single cells avoid inactivation of nitrogenase during these periods? One possibility is that phenotypic heterogeneity in populations leads to segregation of the two processes. Here, we measured N-2 fixation and photosynthesis of individual cells using nanometer-scale secondary ion mass spectrometry (nanoSIMS) to assess both processes in a culture of the unicellular, diazotrophic cyanobacterium Crocosphaera watsonii during a dark-light and a continuous light phase. We compared single-cell rates with bulk rates and gene expression profiles. During the regular dark and light phases, C. watsonii exhibited the temporal segregation of N-2 fixation and photosynthesis commonly observed. However, N-2 fixation and photosynthesis were concurrently measurable at the population level during the subjective dark phase in which cells were kept in the light rather than returned to the expected dark phase. At the single-cell level, though, cells discriminated against either one of the two processes. Cells that showed high levels of photosynthesis had low nitrogen fixing activities, and vice versa. These results suggest that, under ambiguous environmental signals, single cells discriminate against either photosynthesis or nitrogen fixation, and thereby might reduce costs associated with running incompatible processes in the same cell
Crowdbreaks: Tracking Health Trends Using Public Social Media Data and Crowdsourcing
In the past decade, tracking health trends using social media data has shown great promise, due to a powerful combination of massive adoption of social media around the world, and increasingly potent hardware and software that enables us to work with these new big data streams. At the same time, many challenging problems have been identified. First, there is often a mismatch between how rapidly online data can change, and how rapidly algorithms are updated, which means that there is limited reusability for algorithms trained on past data as their performance decreases over time. Second, much of the work is focusing on specific issues during a specific past period in time, even though public health institutions would need flexible tools to assess multiple evolving situations in real time. Third, most tools providing such capabilities are proprietary systems with little algorithmic or data transparency, and thus little buy-in from the global public health and research community. Here, we introduce Crowdbreaks, an open platform which allows tracking of health trends by making use of continuous crowdsourced labeling of public social media content. The system is built in a way which automatizes the typical workflow from data collection, filtering, labeling and training of machine learning classifiers and therefore can greatly accelerate the research process in the public health domain. This work describes the technical aspects of the platform, thereby covering the functionalities at its current state and exploring its future use cases and extensions
How self-awareness is connected to less experience of action crises in personal goal pursuit
In this research, we applied a differential perspective to the study of action crises, i.e., being in an intra-psychic decisional conflict whether to pursue or abandon a goal once difficulties in its pursuit arise. In two studies, we investigated the role of individuals’ levels of self-awareness when experiencing such action crises. Both among professional ballet dancers (daily diary, Study 1) and university undergraduates (preregistered experience sampling, Study 2), individuals with greater levels of (dispositional and situational) self-awareness showed an adaptive, that is, problem-solving oriented way of dealing with difficulties in the pursuit of their (training or study) goals. As a consequence, self-awareness contributed to less experience of action crisis during goal pursuit and, as a result, led to better goal performance
SDE based regression for random PDEs
A simulation based method for the numerical solution of PDE with random coefficients is presented. By the Feynman-Kac formula, the solution can be represented as conditional expectation of a functional of a corresponding stochastic differential equation driven by independent noise. A time discretization of the SDE for a set of points in the domain and a subsequent Monte Carlo regression lead to an approximation of the global solution of the random PDE. We provide an initial error and complexity analysis of the proposed method along with numerical examples illustrating its behaviour
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