Developing Parameter-Reduction Methods on a Biophysical Model of Auditory Hair Cells

Biophysical models describing complex, cellular phenomena typically include systems of nonlinear differential equations with many free parameters. While experimental measurements can fix some parameters, those describing internal cellular processes frequently remain inaccessible. Hence, a proliferation of free parameters risks overfitting the data, limiting the model's predictive power. In this study, we develop robust methods, applying statistical analysis and dynamical-systems theory, to reduce a biophysical model's complexity. We demonstrate our techniques on an elaborate computational model designed to describe active, mechanical motility of auditory hair cells. Specifically, we use two statistical measures, the total-effect and PAWN indices, to rank each free parameter by its influence on selected, core properties of the model. With the resulting ranking, we fix most of the less influential parameters, yielding a low-parameter model with optimal predictive power. We validate the theoretical model with experimental recordings of active hair-bundle motility, specifically by using Akaike and Bayesian information criteria after obtaining maximum-likelihood fits. As a result, we determine the system's most influential parameters, which illuminate its key biophysical elements of the cell's overall features. While we demonstrated our techniques on a concrete example, they provide a general framework, applicable to other biophysical systems

Age Diversity Climate Affecting Individual‐Level Work‐Related Outcomes

The present study answers the call for more studies to investigate the age diversity climate’s effect on individual‐level outcomes. Building on the social identity approach and social exchange theory, we surveyed 110 Italian employees aged between 18 and 61 years old (M = 46.10, SD = 10.02) and investigated the role of age diversity climate in predicting intentions to quit (H1), job‐related wellbeing (H2), and work engagement (H3). Our findings confirmed the hypotheses (H1 and H2), showing the added effect of age diversity climate over and above age, job tenure, role clarity, job demands, job control, perceived support, and perceived job and organizational fit. In fact, age diversity climate accounted for a significant increase in the variance explained for two of the three hypothesized models (i.e., intentions to quit and job‐related wellbeing, but not work engagement). To conclude, this study contributes to the existing literature by showing the age diversity climate’s predictive value for turnover intentions and job‐related wellbeing, and corroborating the importance of supporting age diversity through a variety of Human Resources Management strategies

Effect of wood gasification biochar on soil physicochemical properties and enzyme activities, and on crop yield in a wheat-production system with sub-alkaline soil

Biochar may have beneficial effects on soil depending on its properties and pedoclimatic conditions. Highly sloping soils are prone to erosion and organic matter depletion, and biochar can be useful to restore soil fertility and quality, and crop yields. To test the effect of wood gasification biochar (WGB), we conducted a field experiment applying 0 and 60 Mg ha 1 of WGB only (no fertilizer) to a sub-alkaline and fine-textured soil under Mediterranean climate conditions. The effect of WGB on the soil physicochemical properties and on 12 enzyme activities involved in the C, N, P, and S cycles was monitored during a wheat-growing season along with its effect on grain yield. The results show that WGB was rather recalcitrant, and the application of a high dose of it had no effect on most of the soil physicochemical properties, enzyme activities and wheat grain yield. Since enzyme activities involved in the C cycle were similar in WGB-treated and not-treated soils, WGB failed to stimulate organic matter mineralization during the monitored period, with no contribution to N and P supply. Since WGB can contribute to soil C stock with no detrimental effects on wheat yield, wood gasification can allow recycling waste woody materials of urban origin to produce energy and return biochar back to agricultural soils. We suggest that future studies on WGB focus on the effect of its aging in soil on soil physicochemical and biochemical properties, and on crop performances

Nature’s contribution to people provided by pastoral systems across European, African, and Middle East Mediterranean countries: trends, approaches and gaps

Mediterranean pastoral systems are providers of a wide array of Nature’s Contribution to People (NCP). They are ‘complex systems’ characterized by limited resources and socio-economic dynamics currently threatened by climate and social changes. Despite a growing number of scientifc articles dealing with NCP, there is a high risk that the existing literature has left out the complexity of such systems. In the light of ongoing social, economic, and climatic changes in the Mediterranean basin, neglecting the complexity of pastoral systems can lead to signifcant research biases, missing the priorities afecting the stability and continuity of such systems. A combination of frameworks of analysis provided by the Millennium Ecosystem Assessment and by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services was applied to understand if and to what extent the complexity of Mediterranean pastoral systems has been considered in the available literature. Most of the 126 papers report studies conducted in the European Union zone (102 papers), with the majority in Spain (50). Fewer studies have been conducted in the Middle East (15 papers) and Africa zones (9 papers). Despite results confrming the importance of pastoral systems as providers of NCP, most of the eligible papers focused on regulating NCP. A lack of a multisectoral approach and integration of knowledge suggests that the complexity of Mediterranean pastoral systems has been overlooked by researchers. The creation of ‘hybrid knowledge’ bridging the expertise of diferent stakeholders could be the key ingredient to properly address the complexity of Mediterranean pastoral systems.This study was carried out with the support of project PACTORES (PAstoral ACTORs, ES, and Society as key elements of agro-pastoral systems in the Mediterranean), ERANETMED ‘EURO-MEDITERRANEAN Cooperation through ERANET joint activities and beyond’- Joint Transnational Call 2016 - Environmental challenges and solutions for vulnerable communities (ERANETMED2-72-303). We would like to thank the late Marco Toderi for his considerable help and inspiration and without whom this research would never have been possible. Open access funding provided by Università Politecnica delle Marche within the CRUI-CARE Agreement.info:eu-repo/semantics/publishedVersio