1,955 research outputs found
God’s silent witnesses: Protestant chaplains in the Canadian Military, 1939-1945
This thesis documents the establishment and growth of the Canadian Protestant Chaplain Services during the Second World War. Bishop George Wells, the head of the Protestant Chaplaincy Service, defined the chaplains’ role as “providing for the men’s spiritual and moral welfare.” Despite having such an important role in maintaining the faith of their men, chaplains of the Second World War have been largely ignored within Canadian historiography. One goal of this thesis is to bring to light the story of these men who had to juggle not only their own faith, but the faith of their men in extraordinary circumstances. Chapter one describes the difficulty in creating such a service, including infighting among churches and combating a societal shift towards pacifism that occurred in the 1930s. Chapter two investigates Bishop Well’s role as head of the Chaplaincy service, both his attempts to recruit men and his own racial and religious bias in selecting chaplains. Chapter three examines the work of chaplains on the front lines, and their ability to look after the faith of their men
Applying a SPA model to examine the impact of climate change on GPP of open woodlands and the potential for woody thickening
Woody thickening is a global phenomenon that influences landscape C density, regional ecohydrology and biogeochemical cycling. The aim of the work described here is to test the hypothesis that increased atmospheric CO2 concentration, with or without photosynthetic acclimation, can increase gross primary production (GPP) and that this can explain woody thickening. We examine mechanisms underlying the response of GPP and highlight the importance of changes in soil water content by applying a detailed soil-plant-atmosphere model. Through this model, we show that CO2 enrichment with decreased or increased D and photosynthetic acclimation results in decreased canopy water use because of reduced gs. The decline in water use coupled with increased photosynthesis resulted in increased GPP, water-use efficiency and soil moisture content. This study shows that this is a valid mechanism for GPP increase because of CO2 enrichment coupled with either a decrease or an increase in D, in water-limited environments. We also show that a large increase in leaf area index could be sustained in the future as a result of the increased soil moisture content arising from CO2 enrichment and this increase was larger if D decreases rather than increases in the future. Large-scale predictions arising from this simple conceptual model are discussed and found to be supported in the literature. We conclude that woody thickening in Australia and probably globally can be explained by the changes in landscape GPP and soil moisture balance arising principally from the increased atmospheric CO2 concentration. © 2010 John Wiley & Sons, Ltd
The response of sap flow to pulses of rain in a temperate Australian woodland
In water-limited systems, pulses of rainfall can trigger a cascade of plant physiological responses. However, the timing and size of the physiological response can vary depending on plant and environmental characteristics, such as rooting depth, plant size, rainfall amount, or antecedent soil moisture. We investigated the influence of pulses of rainfall on the response of sap flow of two dominant evergreen tree species, Eucalyptus crebra (a broadleaf) and Callitris glaucophylla (a needle leaved tree), in a remnant open woodland in eastern Australia. Sap flow data were collected using heat-pulse sensors installed in six trees of each species over a 2 year period which encompassed the tail-end of a widespread drought. Our objectives were to estimate the magnitude that a rainfall pulse had to exceed to increase tree water use (i.e., define the threshold response), and to determine how tree and environmental factors influenced the increase in tree water use following a rainfall pulse. We used data filtering techniques to isolate rainfall pulses, and analysed the resulting data with multivariate statistical analysis. We found that rainfall pulses less than 20 mm did not significantly increase tree water use (P>0.05). Using partial regression analysis to hold all other variables constant, we determined that the size of the rain event (P<0.05, R 2=0.59), antecedent soil moisture (P<0.05, R 2=0.29), and tree size (DBH, cm, P<0.05, R 2=0.15), all significantly affected the response to rainfall. Our results suggest that the conceptual Threshold-Delay model describing physiological responses to rainfall pulses could be modified to include these factors. We further conclude that modelling of stand water use over an annual cycle could be improved by incorporating the T-D behaviour of tree transpiration. © 2007 Springer Science+Business Media B.V
Affective Forecasting and Self-Control: Why Anticipating Pride Wins Over Anticipating Shame in a Self-Regulation Context
We demonstrate that anticipating pride from resisting temptation facilitates self-control due to an enhanced focus on the self while anticipating shame from giving in to temptation results in self-control failure due to a focus on the tempting stimulus. In two studies we demonstrate the effects of anticipating pride (vs. shame) on self-control thoughts and behavior over time (Studies 1 and 2) and illustrate the process mechanism of self vs. stimulus focus underlying the differential influence of these emotions on self-control (Study 2). We present thought protocols, behavioral data (quantity consumed) and observational data (number/size of bites) to support our hypotheses
Measuring and Modelling the Dispersal of Pollen and Spores by Wind
Our present understanding of pollen dispersal by wind (anemophily) is quite limited. Due to the stochastic and complex nature of anemophily, modelling the dispersal patterns of the pollen and seeds of wind pollinated plants is not an easy task. The majority of the existing dispersal models are varied and have many conflicting predictions of pollen dispersal distances and concentrations from a source. These discrepancies between models reflect the lack of both short and long distance dispersal data, limiting the ability to seriously test the validity of these models. The main objective of this study was to measure ambient pollen concentrations of various tree and shrub species at both short and long distances from the source. A secondary objective was to measure the parameters involved in the dispersal process of anemophilous pollen and subsequently use these parameters and the empirical data collected to test the accuracy of three analytical mechanistic models of pollen and seed dispersal. The applications of such models are extensive; besides being of use to the allergy-suffering population, present-day issues such as climate change, pollen contamination in GMO crops, and landscape fragmentation raise concerns about whether plants will be able to adapt, disperse, and reproduce effectively in such rapidly changing environments
Comparing the Penman-Monteith equation and a modified Jarvis-Stewart model with an artificial neural network to estimate stand-scale transpiration and canopy conductance
The responses of canopy conductance to variation in solar radiation, vapour pressure deficit and soil moisture have been extensively modelled using a Jarvis-Stewart (JS) model. Modelled canopy conductance has then often been used to predict transpiration using the Penman-Monteith (PM) model. We previously suggested an alternative approach in which the JS model is modified to directly estimate transpiration rather than canopy conductance. In the present study we used this alternative approach to model tree water fluxes from an Australian native forest over an annual cycle. For comparative purposes we also modelled canopy conductance and estimated transpiration via the PM model. Finally we applied an artificial neural network as a statistical benchmark to compare the performance of both models. Both the PM and modified JS models were parameterised using solar radiation, vapour pressure deficit and soil moisture as inputs with results that compare well with previous studies. Both models performed comparably well during the summer period. However, during winter the PM model was found to fail during periods of high rates of transpiration. In contrast, the modified JS model was able to replicate observed sapflow measurements throughout the year although it too tended to underestimate rates of transpiration in winter under conditions of high rates of transpiration. Both approaches to modelling transpiration gave good agreement with hourly, daily and total sums of sapflow measurements with the modified JS and PM models explaining 87% and 86% of the variance, respectively. We conclude that these three approaches have merit at different time-scales. © 2009 Elsevier B.V. All rights reserved
Frequency-Dependent Squeezing for Advanced LIGO
The first detection of gravitational waves by the Laser Interferometer
Gravitational-wave Observatory (LIGO) in 2015 launched the era of gravitational
wave astronomy. The quest for gravitational wave signals from objects that are
fainter or farther away impels technological advances to realize ever more
sensitive detectors. Since 2019, one advanced technique, the injection of
squeezed states of light is being used to improve the shot noise limit to the
sensitivity of the Advanced LIGO detectors, at frequencies above Hz.
Below this frequency, quantum back action, in the form of radiation pressure
induced motion of the mirrors, degrades the sensitivity. To simultaneously
reduce shot noise at high frequencies and quantum radiation pressure noise at
low frequencies requires a quantum noise filter cavity with low optical losses
to rotate the squeezed quadrature as a function of frequency. We report on the
observation of frequency-dependent squeezed quadrature rotation with rotation
frequency of 30Hz, using a 16m long filter cavity. A novel control scheme is
developed for this frequency-dependent squeezed vacuum source, and the results
presented here demonstrate that a low-loss filter cavity can achieve the
squeezed quadrature rotation necessary for the next planned upgrade to Advanced
LIGO, known as "A+."Comment: 6 pages, 2 figures, to be published in Phys. Rev. Let
Rates of nocturnal transpiration in two evergreen temperate woodland species with differing water-use strategies
Nocturnal fluxes may be a significant factor in the annual water budget of forested ecosystems. Here, we assessed sap flow in two co-occurring evergreen species (Eucalyptus parramattensis and Angophora bakeri) in a temperate woodland for 2 years in order to quantify the magnitude of seasonal nocturnal sap flow (En) under different environmental conditions. The two species showed different diurnal water relations, demonstrated by different diurnal curves of stomatal conductance, sap flow and leaf water potential. The relative influence of several microclimatic variables, including wind speed (U), vapour pressure deficit (D), the product of U and D (UD) and soil moisture content, were quantified. D exerted the strongest influence on En (r2 = 0.59-0.86), soil moisture content influenced En when D was constant, but U and UD did not generally influence En. In both species, cuticular conductance (Gc) was a small proportion of total leaf conductance (Gs) and was not a major pathway for En. We found that En was primarily a function of transpiration from the canopy rather than refilling of stem storage, with canopy transpiration accounting for 50-70% of nocturnal flows. Mean En was 6-8% of the 24-h flux across seasons (spring, summer and winter), but was up to 19% of the 24-h flux on some days in both species. Despite different daytime strategies in water use of the two species, both species demonstrated low night-time water loss, suggesting similar controls on water loss at night. In order to account for the impact of En on pre-dawn leaf water potential arising from the influence of disequilibria between root zone and leaf water potential, we also developed a simple model to more accurately predict soil water potential (ψs). © The Author 2010. Published by Oxford University Press. All rights reserved
Fluids and Melts at the Magmatic-Hydrothermal Transition, Recorded by Unidirectional Solidification Textures at Saginaw Hill, Arizona, USA
Fluid exsolution and melt evolution at the magmatic-hydrothermal transition are critical processes driving the metal enrichment of porphyry systems. Coeval fluid and melt inclusion assemblages in unidirectional solidification textures (USTs) at Saginaw Hill—a small, porphyry Cu system in southwestern Arizona—record a dynamic and repetitious process of fluid accumulation and release. The cores of quartz crystals throughout the UST bands host coeval silicate melt and brine inclusions but lack vapor-rich inclusions. This could indicate preferential expulsion of vapor and trapping of high-density brine during episodes of fracturing or the direct exsolution of single-phase high-salinity brine from the silicate melt. In contrast, the rims of UST quartz host abundant coeval brine and vapor inclusions, consistent with liquid-vapor immiscibility at lower pressures compared to the corresponding quartz cores. This transition from dominantly coeval silicate melt inclusions and brine in phenocryst cores to coeval brine and vapor in the rims suggests that the Saginaw Hill system underwent cyclic processes of fluid exsolution, accumulation, overpressure, and decompression at relatively stable temperatures (consistently ~650°C) during UST formation. Melt inclusion data indicate that the melt at this stage was highly fractionated and tended toward muscovite saturation. Metal concentrations in the brine were comparable to or higher than those in fluids reported in world-class porphyry Cu systems and were likely the result of both igneous fractionation and the high chloride content of the exsolved fluids. While limited in scale, Saginaw Hill provides evidence for processes that are predicted to occur at the magmatic-hydrothermal transition during the formation of large, well-mineralized porphyry systems
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