Competition for Flow and Short-Termism in Activism

We develop a dual-layered agency model to study blockholder monitoring by activist funds competing for investor flow. Competition for flow affects the manner in which activist funds govern as blockholders. In particular, funds inflate their short-term performance by increasing payouts that are financed by higher (net) leverage. Doing so subsequently discourages value-creating interventions during economic downturns because of debt overhang. Our theory suggests a new channel via which asset manager incentives may foster economic fragility and links together the observed procyclicality of activist investments with the documented effect of such funds on the leverage of their target companies.

Regional Competition, Labor Force Mobility, and the Fiscal Behaviour of Local Governments in China

At present, China is in a critical period of transition from labor-intensive industries to capital- and technology-intensive industries. Accordingly, the increasing labor force mobility among Chinese cities has promoted competition over production factors among regions, having a significant impact on local governments’ fiscal expenditure structure. A theoretical analysis shows that the competition of livelihood public good expenditures is playing an increasingly important role in the factor flow competition. Different labor forces’ demand for different public goods and local governments’ demand for different labor forces affect the structural preference of local government fiscal expenditures. Based on panel data on Chinese prefecture-level cities in 2010–2016, this paper empirically tests the impact of different labor mobilities on the structure of local government fiscal expenditures, finding that current decision making on labor mobility is increasingly sensitive to the supply of livelihood public goods, and strengthening labor mobility has reversed the expenditure bias historically caused by the government’s simple capital competition. After dividing the mobile labor force based on whether the labor is settled in the current year, the two labor force types’ demand for different livelihood public goods was found to be different. To attract different labor inflows, local governments should promote an increase in relevant livelihood public good expenditures, showing a strategic fiscal expenditure structural bias. Specifically, with increasing new added general labor mobility, local goverments will increase the proportion of fiscal expenditures on education and medical care, combined with the increase of newly added registered labor mobility, which will correspondingly increase the proportion of environmental protection expenditures.

Simulations Reveal Adverse Hemodynamics in Patients With Multiple Systemic to Pulmonary Shunts

For newborns diagnosed with pulmonary atresia or severe pulmonary stenosis leading to insufficient pulmonary blood flow, cyanosis can be mitigated with placement of a modified Blalock–Taussig shunt (MBTS) between the innominate and pulmonary arteries. In some clinical scenarios, patients receive two systemic-to-pulmonary connections, either by leaving the patent ductus arteriosus (PDA) open or by adding an additional central shunt (CS) in conjunction with the MBTS. This practice has been motivated by the thinking that an additional source of pulmonary blood flow could beneficially increase pulmonary flow and provide the security of an alternate pathway in case of thrombosis. However, there have been clinical reports of premature shunt occlusion when more than one shunt is employed, leading to speculation that multiple shunts may in fact lead to unfavorable hemodynamics and increased mortality. In this study, we hypothesize that multiple shunts may lead to undesirable flow competition, resulting in increased residence time (RT) and elevated risk of thrombosis, as well as pulmonary overcirculation. Computational fluid dynamics-based multiscale simulations were performed to compare a range of shunt configurations and systematically quantify flow competition, pulmonary circulation, and other clinically relevant parameters. In total, 23 cases were evaluated by systematically changing the PDA/CS diameter, pulmonary vascular resistance (PVR), and MBTS position and compared by quantifying oxygen delivery (OD) to the systemic and coronary beds, wall shear stress (WSS), oscillatory shear index (OSI), WSS gradient (WSSG), and RT in the pulmonary artery (PA), and MBTS. Results showed that smaller PDA/CS diameters can lead to flow conditions consistent with increased thrombus formation due to flow competition in the PA, and larger PDA/CS diameters can lead to insufficient OD due to pulmonary hyperfusion. In the worst case scenario, it was found that multiple shunts can lead to a 160% increase in RT and a 10% decrease in OD. Based on the simulation results presented in this study, clinical outcomes for patients receiving multiple shunts should be critically investigated, as this practice appears to provide no benefit in terms of OD and may actually increase thrombotic risk.

Study of Multiple Systemic-to-Pulmonary Shunts in Single Ventricle Hearts

For newborns diagnosed with single ventricle hearts and insufficient blood flow to the lungs, their lack of oxygen in the blood can be remedied with a modified Blalock-Taussig shunt (BTshunt) between the innominate and pulmonary artery. However, some surgeons prefer to have two systemic-to-pulmonary shunts, by either leaving the ductus arteriosus open or construct a second BT shunt, to provide additional pulmonary blood flow. There have been clinical reports of premature shunt occlusion when more than one shunt is employed, and a recent audit of shunt operations at a single institution has revealed increased mortality. There are speculation that these adverse outcomes can be due to flow competition between the two shunts, and/or having too much pulmonary blood flow. The flow dynamics and cardiopulmonary physiology in single ventricle circulations where pulmonary blood flow is supplied by more than one shunt has not been studied previously. In this study, we adopted CFD-based multi-domain simulations to compare a range of shunt configurations to examine the issue of flow competition and pulmonary overcirulation.

Topo-edaphic controls over woody plant biomass in South African savannas

The distribution of woody biomass in savannas reflects spatial patterns fundamental to ecosystem processes, such as water flow, competition, and herbivory, and is a key contributor to savanna ecosystem services, such as fuelwood supply. While total precipitation sets an upper bound on savanna woody biomass, the extent to which substrate and terrain constrain trees and shrubs below this maximum remains poorly understood, often occluded by local-scale disturbances such as fire and trampling. Here we investigate the role of hillslope topography and soil properties in controlling woody plant aboveground biomass (AGB) in Kruger National Park, South Africa. Large-area sampling with airborne Light Detection and Ranging (LiDAR) provided a means to average across local-scale disturbances, revealing an unexpectedly linear relationship between AGB and hillslope-position on basalts, where biomass levels were lowest on crests, and linearly increased toward streams (R2 = 0.91). The observed pattern was different on granite substrates, where AGB exhibited a strongly non-linear relationship with hillslope position: AGB was high on crests, decreased midslope, and then increased near stream channels (R2 = 0.87). Overall, we observed 5-to-8-fold lower AGB on clayey, basalt-derived soil than on granites, and we suggest this is due to herbivore-fire interactions rather than lower hydraulic conductivity or clay shrinkage/swelling, as previously hypothesized. By mapping AGB within and outside fire and herbivore exclosures, we found that basalt-derived soils support tenfold higher AGB in the absence of fire and herbivory, suggesting high clay content alone is not a proximal limitation on AGB. Understanding how fire and herbivory contribute to AGB heterogeneity is critical to predicting future savanna carbon storage under a changing climate.

Topo-edaphic controls over woody plant biomass in South African savannas

The distribution of woody biomass in savannas reflects spatial patterns fundamental to ecosystem processes, such as water flow, competition, and herbivory, and is a key contributor to savanna ecosystem services, such as fuelwood supply. While total precipitation sets an upper bound on savanna woody biomass, the extent to which substrate and terrain constrain trees and shrubs below this maximum remains poorly understood, often occluded by local-scale disturbances such as fire and trampling. Here we investigate the role of hillslope topography and soil properties in controlling woody plant aboveground biomass (AGB) in Kruger National Park, South Africa. Large-area sampling with airborne Light Detection and Ranging (LiDAR) provided a means to average across local-scale disturbances, revealing an unexpectedly linear relationship between AGB and hillslope-position on basalts, where biomass levels were lowest on crests, and linearly increased toward streams (R2 = 0.91). The observed pattern was different on granite substrates, where AGB exhibited a strongly non-linear relationship with hillslope position: AGB was high on crests, decreased midslope, and then increased near stream channels (R2 = 0.87). Overall, we observed 5-to-8-fold lower AGB on clayey, basalt-derived soil than on granites, and we suggest this is due to herbivore-fire interactions rather than lower hydraulic conductivity or clay shrinkage/swelling, as previously hypothesized. By mapping AGB within and outside fire and herbivore exclosures, we found that basalt-derived soils support tenfold higher AGB in the absence of fire and herbivory, suggesting high clay content alone is not a~proximal limitation on AGB. Understanding how fire and herbivory contribute to AGB heterogeneity is critical to predicting future savanna carbon storage under a changing climate.