True Religion and Hume's Practical Atheism

The argument and discussion in this paper begins from the premise that Hume was an atheist who denied the religious or theist hypothesis. However, even if it is agreed that that Hume was an atheist this does not tell us where he stood on the question concerning the value of religion. Some atheists, such as Spinoza, have argued that society needs to maintain and preserve a form of “true religion”, which is required for the support of our ethical life. Others, such as D’Holbach have argued that religion is not only false it is pernicious and it should be eradicated. This paper argues that Hume rejected both theseproposals, on the ground that they rest, in different ways, on excessively optimistic assumptions. The sensible, practical form of atheism that Hume defends has a more modest and realistic aim, which is simply to restrict and limit the most pernicious forms of religion. Understood this way, Hume’s practical atheism is very different from the forms of “old” atheism associated with Spinoza and D’Holbach, as well as from the “new atheism” of thinkers such as Dawkins and Dennett. Reprinted in Paul Russell, "Recasting Hume and Early Modern Philosophy: Selected Essays" (New York: Oxford University Press, 2021): 340-383

Daily 30-min exposure to artificial gravity during 60 days of bed rest does not maintain aerobic exercise capacity but mitigates some deteriorations of muscle function: results from the AGBRESA RCT

Purpose: Spaceflight impairs physical capacity. Here we assessed the protective effect of artificial gravity (AG) on aerobic exercise capacity and muscle function during bed rest, a spaceflight analogue. Methods: 24 participants (33 ± 9 years, 175 ± 9 cm, 74 ± 10 kg, 8 women) were randomly allocated to one of three groups: continuous AG (cAG), intermittent AG (iAG) or control (CTRL). All participants were subjected to 60 days of six-degree head-down tilt bed rest, and subjects of the intervention groups completed 30 min of centrifugation per day: cAG continuously and iAG for 6 × 5 min, with an acceleration of 1g at the center of mass. Physical capacity was assessed before and after bed rest via maximal voluntary contractions, cycling spiroergometry, and countermovement jumps. Results: AG had no significant effect on aerobic exercise capacity, flexor muscle function and isometric knee extension strength or rate of force development (RFD). However, AG mitigated the effects of bed rest on jumping power (group * time interaction of the rmANOVA p < 0.001; iAG − 25%, cAG − 26%, CTRL − 33%), plantar flexion strength (group * time p = 0.003; iAG − 35%, cAG − 31%, CTRL − 48%) and plantar flexion RFD (group * time p = 0.020; iAG − 28%, cAG − 12%, CTRL − 40%). Women showed more pronounced losses than men in jumping power (p < 0.001) and knee extension strength (p = 0.010). Conclusion: The AG protocols were not suitable to maintain aerobic exercise capacity, probably due to the very low cardiorespiratory demand of this intervention. However, they mitigated some losses in muscle function, potentially due to the low-intensity muscle contractions during centrifugation used to avoid presyncope

Dynamic analysis of stream flow and water chemistry to infer subsurface water and nitrate fluxes in a lowland dairying catchment

The use of process-based, dynamic and spatially-explicit models to describe water and nitrogen fluxes at the catchment-scale is often hampered by a shortage of detailed land use, hydrological and biogeochemical information. Accordingly, such complex models tend to be restricted to a small number of well investigated catchments, often associated with research projects. On the other hand, stream flow and stream water chemistry time series data are available for a much larger number of catchments, e.g. for many catchments that are routinely monitored by government agencies for state-of-the-environment reporting. It was the main aim of this study to provide a spatially lumped model that allows meaningful analysis of catchment-scale water and nitrate fluxes based on such data sets.Based on stream flow time series data, catchment hydrodynamics are often analysed using approaches derived from the linearised Boussinesq equation, which has analytical solutions for dynamic groundwater discharge expressed in terms of eigenvalues and eigenfunctions (eigenmodel approach). Calibrated Boussinesq models generally yield a good reproduction of stream flow dynamics, and stable estimates for aquifer parameters such as hydraulic conductivity and mean aquifer depth. By linking a soil water balance model with two Boussinesq groundwater eigenmodels linked in series, and assuming constant solute concentrations discharging from each source, a dynamic catchment model predicting stream flow and water chemistry at the catchment outlet ("StreamGEM") was developed. Compared with previous approaches, inclusion of water chemistry in this model both aided hydrological understanding, and allowed assessment of catchmentscale nitrate fluxes.Simultaneous calibration of the model to stream flow and nitrate concentration data from a small lowland dairying catchment yielded good predictions to both variables (Nash-Sutcliffe Model Efficiency of 0.90 and 0.84), and the fitted parameters were able to be used to estimate annual flow and nitrate fluxes through near-surface, shallow groundwater, and deeper groundwater reservoirs conceptually present in the catchment. The calibration was cross-validated using an independent time series from the same catchment.The results support the hypothesis, based on groundwater observations, that stream flow in the catchment is the result of mixed discharge from a shallower, rapidly draining zone of oxidised groundwater carrying relatively high loads of agricultural nitrate, with a relatively deeper and slower draining zone of reduced groundwater that is essentially nitrate free. The proportions of stream flow discharging from the near-surface, shallow groundwater, and deeper groundwater reservoirs were estimated to be 5%, 80% and 15%, respectively. In spite of its small contribution to total stream flow, the deeper groundwater reservoir sustained stream flow during summer and dominated stream water chemistry 61% of the time.By combining the flow and nitrate concentration estimates derived from model calibration, it was estimated that discharge of shallow groundwater was responsible for 91% of the nitrate load entering the stream. However, the predicted nitrate concentration in this reservoir was significantly lower than the predicted nitrate concentration of near-surface flow and root zone leachate concentrations estimated using a nutrient budgeting model. This indicates that denitrification occurs within this reservoir. On the basis of the calibrated model, it was estimated that 36% of the nitrate recharged from the vadose zone gets denitrified within the shallow groundwater reservoir, and up to 9% in the deeper groundwater reservoir. © 2013 Elsevier B.V