Behavioural activation by mental health nurses for late-life depression in primary care: a randomized controlled trial

Background: Depressive symptoms are common in older adults. The effectiveness of pharmacological treatments and the availability of psychological treatments in primary care are limited. A behavioural approach to depression treatment might be beneficial to many older adults but such care is still largely unavailable. Behavioural Activation (BA) protocols are less complicated and more easy to train than other psychological therapies, making them very suitable for delivery by less specialised therapists. The recent introduction of the mental health nurse in primary care centres in the Netherlands has created major opportunities for improving the accessibility of psychological treatments for late-life depression in primary care. BA may thus address the needs of older patients while improving treatment outcome and lowering costs.The primary objective of this study is to compare the effectiveness and cost-effectiveness of BA in comparison with treatment as usual (TAU) for late-life depression in Dutch primary care. A secondary goal is to explore several potential mechanisms of change, as well as predictors and moderators of treatment outcome of BA for late-life depression. Methods/design: Cluster-randomised controlled multicentre trial with two parallel groups: a) behavioural activation, and b) treatment as usual, conducted in primary care centres with a follow-up of 52 weeks. The main inclusion criterion is a PHQ-9 score > 9. Patients are excluded from the trial in case of severe mental illness that requires specialized treatment, high suicide risk, drug and/or alcohol abuse, prior psychotherapy, change in dosage or type of prescribed antidepressants in the previous 12 weeks, or moderate to severe cognitive impairment. The intervention consists of 8 weekly 30-min BA sessions delivered by a trained mental health nurse. Discussion: We expect BA to be an effective and cost-effective treatment for late-life depression compared to TAU. BA delivered by mental health nurses could increase the availability and accessibility of non-pharmacological treatments for late-life depression in primary care. Trial registration: This study is retrospectively registered in the Dutch Clinical Trial Register NTR6013on August 25th 2016. © 2017 The Author(s)

Dust outpaces bedrock in nutrient supply to montane forest ecosystems.

Dust provides ecosystem-sustaining nutrients to landscapes underlain by intensively weathered soils. Here we show that dust may also be crucial in montane forest ecosystems, dominating nutrient budgets despite continuous replacement of depleted soils with fresh bedrock via erosion. Strontium and neodymium isotopes in modern dust show that Asian sources contribute 18-45% of dust deposition across our Sierra Nevada, California study sites. The remaining dust originates regionally from the nearby Central Valley. Measured dust fluxes are greater than or equal to modern erosional outputs from hillslopes to channels, and account for 10-20% of estimated millennial-average inputs of bedrock P. Our results demonstrate that exogenic dust can drive the evolution of nutrient budgets in montane ecosystems, with implications for predicting forest response to changes in climate and land use

Dust outpaces bedrock in nutrient supply to montane forest ecosystems.

Dust provides ecosystem-sustaining nutrients to landscapes underlain by intensively weathered soils. Here we show that dust may also be crucial in montane forest ecosystems, dominating nutrient budgets despite continuous replacement of depleted soils with fresh bedrock via erosion. Strontium and neodymium isotopes in modern dust show that Asian sources contribute 18-45% of dust deposition across our Sierra Nevada, California study sites. The remaining dust originates regionally from the nearby Central Valley. Measured dust fluxes are greater than or equal to modern erosional outputs from hillslopes to channels, and account for 10-20% of estimated millennial-average inputs of bedrock P. Our results demonstrate that exogenic dust can drive the evolution of nutrient budgets in montane ecosystems, with implications for predicting forest response to changes in climate and land use

Geophysical constraints on deep weathering and water storage potential in the Southern Sierra Critical Zone Observatory

The conversion of bedrock to regolith marks the inception of critical zone processes, but the factors that regulate it remain poorly understood. Although the thickness and degree of weathering of regolith are widely thought to be important regulators of the development of regolith and its water-storage potential, the functional relationships between regolith properties and the processes that generate it remain poorly documented. This is due in part to the fact that regolith is difficult to characterize by direct observations over the broad scales needed for process-based understanding of the critical zone. Here we use seismic refraction and resistivity imaging techniques to estimate variations in regolith thickness and porosity across a forested slope and swampy meadow in the Southern Sierra Critical Zone Observatory (SSCZO). Inferred seismic velocities and electrical resistivities image a weathering zone ranging in thickness from 10 to 35m (average=23m) along one intensively studied transect. The inferred weathering zone consists of roughly equal thicknesses of saprolite (P-velocity<2kms-1) and moderately weathered bedrock (P-velocity=2-4kms-1). A minimum-porosity model assuming dry pore space shows porosities as high as 50% near the surface, decreasing to near zero at the base of weathered rock. Physical properties of saprolite samples from hand augering and push cores are consistent with our rock physics model when variations in pore saturation are taken into account. Our results indicate that saprolite is a crucial reservoir of water, potentially storing an average of 3m3m-2 of water along a forested slope in the headwaters of the SSCZO. When coupled with published erosion rates from cosmogenic nuclides, our geophysical estimates of weathering zone thickness imply regolith residence times on the order of 105years. Thus, soils at the surface today may integrate weathering over glacial-interglacial fluctuations in climate. © 2013 John Wiley & Sons, Ltd

Climatic control of denudation in the deglaciated landscape of the Washington cascades

Since the Last Glacial Maximum, the extent of glaciers in many mountainous regions has declined, and erosion driven by glacial processes has been supplanted by fluvial incision and mass wasting processes. This shift in the drivers of erosion is thought to have altered the rate and pattern of denudation of these landscapes. The Washington Cascades Mountains in the northwestern USA still bear the topographic imprint of Pleistocene glaciations, and are affected by large variations in precipitation, making them an ideal setting to assess the relative controls of denudation. Here we show that denudation rates over the past millennia, as determined by 10Be exposure ages, range from 0.08 to 0.57 mm yr−1, about four times higher than the rates inferred for million-year timescales. We find that the millennial timescale denudation rates increase linearly with modern precipitation rates. Based on our landscape analyses, we suggest that this relationship arises because intense precipitation triggers landslides, particularly on slopes that have been steepened by glacial erosion before or during the Last Glacial Maximum. We conclude that the high modern interglacial denudation rates we observe in the Washington Cascades are driven by a disequilibrium between the inherited topography and the current spatial distribution of erosional processes that makes this range particularly sensitive to spatial variations in climate