375 research outputs found

    Assessing the reduction of the hydrological connectivity of gully systems through vegetation restoration: field experiments and numerical modelling

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    Restoration of degraded land in the Southern Ecuadorian Andes has led to alterations in the functioning of degraded catchments. Recovery of vegetation on areas affected by overgrazing, as well as the reforestation or afforestation of gully areas have given rise to modifications of hydrological connectivity within the catchments. Recent research has highlighted the ability of gully channels to trap sediment eroded from steep slopes, especially if vegetation is established along the gully bed. However, vegetation cover not only induces sediment deposition in the gully bed, but may also have a potential to reduce runoff water volume. The performance of gully beds in reducing the transfer of runoff was investigated by conducting controlled concentrated flow experiments in the field. Experimental field data for nine gullies were derived by pouring concentrated inflow into the upstream end and measuring the outflow at the downstream end of the channel. Two consecutive flow experiments per gully were carried out, so that data for dry and wet soil conditions were collected. The hydrological response to concentrated flow was estimated for each experiment by calculating its cumulative infiltration coefficient, <i>IC</i> (%). The results showed a great difference in <i>IC</i> between dry and wet soil conditions. The <i>IC</i> for wet soil conditions was on average 24%, whereas it was 60% for dry conditions. Gullies with more than 50% surface vegetation cover exhibit the highest cumulative infiltration coefficients (81% for dry runs, and 34% for wet runs), but runoff transmission losses were not as clearly related to vegetation cover as sediment storage as shown in Molina et al. (2009). The experimental field data of 16 experiments were used to calibrate a hydrological model developed by Fiener and Auerswald (2005) in order to simulate the transfer of concentrated flow along the gully beds. The calibrated model was able to simulate the transfer of runoff water well, as the error on the simulated total outflow volumes is below 13% for 15 out of 16 cases. However, predicting infiltration amounts is difficult: the high sensitivity of model results to some crucial hydraulic parameters (runoff width, hydraulic conductivity and sorptivity) is one of the reasons why the relationships between model parameter values and gully features are relatively weak. <br><br> The results obtained from the field experiments show that gully systems are key elements in the hydrological connectivity of degraded landscapes. The transfer of overland flow and sediment from the slopes towards the river system highly depends on the presence/absence of vegetation in the gully beds and should therefore be accounted for in assessments of landscape degradation and/or recovery

    Slack resources, firm performance, and the institutional context: Evidence from privately held European firms

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    This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordResearch summary: Integrating the behavioral and institutional perspectives, we propose that a country's formal institutions, particularly its legal frameworks, affect managers' deployment of slack resources. Specifically, we explore the moderating effects of creditor and employee rights on the performance effects of slack. Using longitudinal data from 162,633 European private firms in 26 countries, we find that financial slack enhances firm performance at diminishing rates, whereas human resource (HR) slack lowers performance at diminishing rates. However, financial slack has a more positive effect on firm performance in countries with weaker creditor rights, whereas HR slack has a more negative effect on performance in countries with stronger employee rights. The results provide a richer view of the relationship between slack and firm performance than currently assumed in the literature. Managerial summary: A key dilemma managers often encounter is whether, on the one hand, they should build in excess resources to buffer their firms from internal and external shocks and to pursue new opportunities or whether, on the other hand, they should develop “lean” firms. Our study suggests that excess cash resources—which are usually viewed as easy to redeploy—benefit firm performance, especially when firms operate in countries with weaker creditor rights. However, excess human resources—which are usually viewed as more difficult to redeploy—hamper firm performance, particularly when firms operate in countries with stronger labor protection laws. Thus, the management of slack resources critically depends on the characteristics of these resources (e.g., redeployability) and the institutional context in which managers operate. Copyright © 2016 John Wiley & Sons, Ltd.Research Foundation—FlandersNational Bank of BelgiumHercules FoundationKU Leuve

    False signaling by platform team members and post-campaign venture outcomes: Evidence from an equity crowdfunding platform

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    This is the final version. Available from Elsevier via the DOI in this record. Data availability: The data that has been used is confidential.In equity crowdfunding (ECF), early investments serve as signals of venture potential to prospective investors, making them more likely to join an offering. We argue that ECF platform team members can exploit this mechanism and convey false signals to unsophisticated investors. Data from a prominent ECF platform indicate that platform team members “invest” in ventures that exhibit weaker post-campaign outcomes. However, in ventures that successfully fundraise, platform team members typically withdraw their investment (after it incentivized others to join), and these ventures show even weaker post-campaign outcomes. Finally, ventures' post-campaign outcomes are particularly weak when this “invest-and-withdraw” tactic is executed by the platform's upper echelons, whose investments can further be perceived as endorsement signals by the crowd, despite significant goal incongruence between the upper echelons and the crowd. Our study presents novel theoretical and empirical insights into the signaling, financial misconduct, and ECF literature, and holds important policy implications.The Research Foundation — FlandersItalian Ministry of University and Research PRIN programmeSpecial Research Fund (BOF) of Ghent Universit

    Equity Crowdfunders’ Human Capital and Signal Set Formation: Evidence from Eye Tracking

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    This is the author accepted manuscript. The final version is available from SAGE via the DOI in this record.Signaling theory typically assumes that attention is always given to observable signals. We study signal receivers’ formation of signal sets—the signals to which receivers attend and that they can use for subsequent interpretations. Drawing on a cognitive perspective, we argue that signal receivers’ human capital influences the volume and type of signals they attend to and the time they take to form signal sets. Using eye tracking, we show that equity crowdfunders do not attend to many signals that are easily observable on a campaign page, and that differences in crowdfunders’ human capital uniquely affect their signal set formation.Research Foundation – Flander

    Subcellular compartmentation of glutathione in dicotyledonous plants

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    This study describes the subcellular distribution of glutathione in roots and leaves of different plant species (Arabidopsis, Cucurbita, and Nicotiana). Glutathione is an important antioxidant and redox buffer which is involved in many metabolic processes including plant defense. Thus information on the subcellular distribution in these model plants especially during stress situations provides a deeper insight into compartment specific defense reactions and reflects the occurrence of compartment specific oxidative stress. With immunogold cytochemistry and computer-supported transmission electron microscopy glutathione could be localized in highest contents in mitochondria, followed by nuclei, peroxisomes, the cytosol, and plastids. Within chloroplasts and mitochondria, glutathione was restricted to the stroma and matrix, respectively, and did not occur in the lumen of cristae and thylakoids. Glutathione was also found at the membrane and in the lumen of the endoplasmic reticulum. It was also associated with the trans and cis side of dictyosomes. None or only very little glutathione was detected in vacuoles and the apoplast of mesophyll and root cells. Additionally, glutathione was found in all cell compartments of phloem vessels, vascular parenchyma cells (including vacuoles) but was absent in xylem vessels. The specificity of this method was supported by the reduction of glutathione labeling in all cell compartments (up to 98%) of the glutathione-deficient Arabidopsis thaliana rml1 mutant. Additionally, we found a similar distribution of glutathione in samples after conventional fixation and rapid microwave-supported fixation. Thus, indicating that a redistribution of glutathione does not occur during sample preparation. Summing up, this study gives a detailed insight into the subcellular distribution of glutathione in plants and presents solid evidence for the accuracy and specificity of the applied method

    Relocation to get venture capital : a resource dependence perspective

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    This is the author accepted manuscript. The final version is available from SAGE via the DOI in this record.Using a resource dependence perspective, we theorize and show that non-venture-capital-backed ventures founded in U.S. states with a lower availability of venture capital (VC) are more likely to relocate to California (CA) or Massachusetts (MA)—the two VC richest states—compared to ventures founded in states with a greater availability of VC. Moreover, controlling for self-selection, ventures that relocate to CA or MA subsequently have a greater probability of attracting initial VC compared to ventures that stay in their home state. We discuss the implications for theory, future research, and practice
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