121 research outputs found
Ectomycorrhizal fungal communities are dominated by mammalian dispersed truffle-like taxa in north-east Australian woodlands
Mycorrhizal fungi are very diverse, including those that produce truffle-like fruiting bodies. Truffle-like fungi are hypogeous and sequestrate (produced below-ground, with an enclosed hymenophore) and rely on animal consumption, mainly by mammals, for spore dispersal. This dependence links mycophagous mammals to mycorrhizal diversity and, assuming truffle-like fungi are important components of mycorrhizal communities, to plant nutrient cycling and ecosystem health. These links are largely untested as currently little is known about mycorrhizal fungal community structure and its dependence on mycophagous mammals. We quantified the mycorrhizal fungal community in the north-east Australian woodland, including the portion interacting with ten species of mycophagous mammals. The study area is core habitat of an endangered fungal specialist marsupial, Bettongia tropica, and as such provides baseline data on mycorrhizal fungi-mammal interactions in an area with no known mammal declines. We examined the mycorrhizal fungi in root and soil samples via high-throughput sequencing and compared the observed taxa to those dispersed by mycophagous mammals at the same locations. We found that the dominant root-associating ectomycorrhizal fungal taxa (> 90% sequence abundance) included the truffle-like taxa Mesophellia, Hysterangium and Chondrogaster. These same taxa were also present in mycophagous mammalian diets, with Mesophellia often dominating. Altogether, 88% of truffle-like taxa from root samples were shared with the fungal specialist diet and 52% with diets from generalist mammals. Our data suggest that changes in mammal communities, particularly the loss of fungal specialists, could, over time, induce reductions to truffle-like fungal diversity, causing ectomycorrhizal fungal communities to shift with unknown impacts on plant and ecosystem health
Microscopic theory for the light-induced anomalous Hall effect in graphene
We employ a quantum Liouville equation with relaxation to model the recently
observed anomalous Hall effect in graphene irradiated by an ultrafast pulse of
circularly polarized light. In the weak-field regime, we demonstrate that the
Hall effect originates from an asymmetric population of photocarriers in the
Dirac bands. By contrast, in the strong-field regime, the system is driven into
a non-equilibrium steady state that is well-described by topologically
non-trivial Floquet-Bloch bands. Here, the anomalous Hall current originates
from the combination of a population imbalance in these dressed bands together
with a smaller anomalous velocity contribution arising from their Berry
curvature. This robust and general finding enables the simulation of electrical
transport from light-induced Floquet-Bloch bands in an experimentally relevant
parameter regime and creates a pathway to designing ultrafast quantum devices
with Floquet-engineered transport properties
Floquet dynamics in light-driven solids
We demonstrate how the properties of light-induced electronic Floquet states
in solids impact natural physical observables, such as transport properties, by
capturing the environmental influence on the electrons. We include the
environment as dissipative processes, such as inter-band decay and dephasing,
often ignored in Floquet predictions. These dissipative processes determine the
Floquet band occupations of the emergent steady state, by balancing out the
optical driving force. In order to benchmark and illustrate our framework for
Floquet physics in a realistic solid, we consider the light-induced Hall
conductivity in graphene recently reported by J.~W.~McIver, et al., Nature
Physics (2020). We show that the Hall conductivity is estimated by the Berry
flux of the occupied states of the light-induced Floquet bands, in addition to
the kinetic contribution given by the average band velocity. Hence, Floquet
theory provides an interpretation of this Hall conductivity as a
geometric-dissipative effect. We demonstrate this mechanism within a master
equation formalism, and obtain good quantitative agreement with the
experimentally measured Hall conductivity, underscoring the validity of this
approach which establishes a broadly applicable framework for the understanding
of ultrafast non-equilibrium dynamics in solids
Mindfulness-Based School Interventions: a Systematic Review of Outcome Evidence Quality by Study Design
OBJECTIVE: The purpose of this systematic review was to assess the current literature on mindfulness-based school interventions (MBSIs) by evaluating evidence across specific outcomes for youth. METHODS: We evaluated 77 studies with a total sample of 12,358 students across five continents, assessing the quality of each study through a robust coding system for evidence-based guidelines. Coders rated each study numerically per study design as 1++ (RCT with a very low risk of bias) to 4 (expert opinion) and across studies for the corresponding evidence letter grade, from highest quality (‘A Grade’) to lowest quality (‘D Grade’) evidence. RESULTS: The highest quality evidence (‘A Grade’) across outcomes indicated that MBSIs increased prosocial behavior, resilience, executive function, attention and mindfulness, and decreased anxiety, attention problems/ADHD behaviors and conduct behaviors. The highest quality evidence for well-being was split, with some studies showing increased well-being and some showing no improvements. The highest quality evidence suggests MBSIs have a null effect on depression symptoms. CONCLUSION: This review demonstrates the promise of incorporating mindfulness interventions in school settings for improving certain youth outcomes. We urge researchers interested in MBSIs to study their effectiveness using more rigorous designs (e.g., RCTs with active control groups, multi-method outcome assessment, and follow-up evaluation), to minimize bias and promote higher quality—not just increased quantity—evidence that can be relied upon to guide school-based practice
Mindfulness-based school interventions: A systematic review of outcome evidence quality by study design.
Objective: The purpose of this systematic review was to assess the current literature on mindfulness-based school interventions (MBSIs) by evaluating evidence across specific outcomes for youth.
Methods: We evaluated 77 studies with a total sample of 12,358 students across five continents, assessing the quality of each study through a robust coding system for evidence-based guidelines. Coders rated each study numerically per study design as 1++ (RCT with a very low risk of bias) to 4 (expert opinion) and across studies for the corresponding evidence letter grade, from highest quality (\u27A Grade\u27) to lowest quality (\u27D Grade\u27) evidence.
Results: The highest quality evidence (\u27A Grade\u27) across outcomes indicated that MBSIs increased prosocial behavior, resilience, executive function, attention and mindfulness, and decreased anxiety, attention problems/ADHD behaviors and conduct behaviors. The highest quality evidence for well-being was split, with some studies showing increased well-being and some showing no improvements. The highest quality evidence suggests MBSIs have a null effect on depression symptoms.
Conclusion: This review demonstrates the promise of incorporating mindfulness interventions in school settings for improving certain youth outcomes. We urge researchers interested in MBSIs to study their effectiveness using more rigorous designs (e.g., RCTs with active control groups, multi-method outcome assessment, and follow-up evaluation), to minimize bias and promote higher quality-not just increased quantity-evidence that can be relied upon to guide school-based practice
Women's gambling behaviour, product preferences, and perceptions of product harm: Differences by age and gambling risk status
Background: Women's participation in, and harm from gambling, is steadily increasing. There has been very limited research to investigate how gambling behaviour, product preferences, and perceptions of gambling harm may vary across subgroups of women. Methods: This study surveyed a convenience sample of 509 women from Victoria and New South Wales, Australia. Women were asked a range of questions about their socio-demographic characteristics and gambling behaviour. Focusing on four gambling products in Australia-casino gambling, electronic gambling machines (EGMs), horse betting, and sports betting-women were asked about their frequency of participation, their product preferences, and perceptions of product harms. The sample was segmented a priori according to age and gambling risk status, and differences between groups were identified using Chi-square tests and ANOVAs. Thematic analysis was used to interpret qualitative data. Results: Almost two thirds (n=324, 63.7%) of women had engaged with one of the four products in the previous 12 months. Compared to other age groups, younger women aged 16-34 years exhibited a higher proportion of problem gambling, gambled more frequently, and across more products. While EGMs were the product gambled on most frequently by women overall, younger women were significantly more likely to bet on sports and gamble at casinos relative to older women. Qualitative data indicated that younger women engaged with gambling products as part of a 'night out', 'with friends', due to their 'ease of access' and perceived 'chance of winning big'. There were significant differences in the perceptions of the harms associated with horse and sports betting according to age and gambling risk status, with younger women and gamblers perceiving these products as less harmful. Conclusions: This study highlights that there are clear differences in the gambling behaviour, product preferences, and perceptions of product harms between subgroups of women. A gendered approach will enable public health researchers and policymakers to ensure that the unique factors associated with women's gambling are taken into consideration in a comprehensive public health approach to reducing and preventing gambling harm
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