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Major depressive disorder (MDD) has increasing prevalence with age. Both objective measures of cognitive dysfunction and subjective report of cognitive difficulties related to MDD are often thought to worsen with increasing age. However, few studies have directly evaluated these characteristics across the adult lifespan.Participants included 23,594 adults completing objective and subjective measures of cognition on an online research registry. Linear regression including interactions of age group with depression was used to evaluate the association of self-reported MDD with measures of cognition in three age groups: 21-40 years; 41-60 years; 61+ years.MDD (n = 2127) demonstrated poorer objective cognitive performance and greater subjective ratings of cognitive difficulties across all domains assessed compared to non-depressed individuals (ND; n = 21,467). Significant interactions of age group and MDD status with objective and subjective measures of cognition were observed for both middle age and older adults when compared to young adults but few significant differences between middle-aged and older adults were evident.This study relied on self-report of MDD diagnosis, utilized remotely administered and unsupervised measures of cognition, and the sample was not diverse.The magnitude of association between MDD and cognitive correlates appears to plateau in middle age. Our results suggest that increased rates of dementia are not due to greater cognitive consequence of MDD in older adults and that age effects, and not greater effects of depression, may lead to increased diagnosis of MDD based on subjective report of cognitive symptoms.

BackgroundNeuropsychiatric symptoms are highly prevalent in frontotemporal degeneration (FTD). Prior research suggests there are disparities in the clinical presentation of dementia when comparing Black and White individuals but this has not been investigated in the context of FTD specifically. The aim of the present study is to investigate racial disparities in dementia severity, functional impairment and neuropsychiatric symptoms in individuals with a clinical diagnosis of FTD.MethodsUsing National Alzheimer’s Coordinating Center (NACC) data, we evaluated 63 Black and 2,356 White individuals living with a clinical diagnosis of FTD (behavioral variant FTD or primary progressive aphasia) and a healthy control group of 1899 Black and 9122 White individuals with normal behavior and cognition. We compared demographic characteristics, dementia severity, functional impairment and neuropsychiatric symptoms at initial NACC visit by examining differences on Clinical Dementia Rating Scale (CDR), Functional Assessment Scale (FAS) and Neuropsychiatric Inventory (NPI) using multivariable linear and logistic regression models, covarying for age at visit, disease duration, sex, and education. Models evaluating differences in neuropsychiatric symptoms additionally controlled for dementia severity.ResultsBlack individuals with FTD were considerably underrepresented, comprising only 2.5% of the clincial sample. In comparison to White individuals, Black individuals with FTD had a higher degree of dementia severity on CDR (CDR sum of boxes; p=0.03 CDR global, p=.006), greater functional impairment (FAS total; p=0.01) and more delusions (p=0.01), agitation (p=0.04) and depression (p=0.03) on the NPI. White individuals with FTD were more likely to demonstrate apathy (p=0.03). Within the normal control group, Black individuals reported less depression, anxiety, agitation, and nighttime behaviors (depression; p < 0.001; anxiety; p = 0.006; agitation; p = 0.048; nighttime behaviors; p < 0.001) compared to White normal controls.DiscussionThe present study suggests there are significant disparities in dementia severity, functional impairment and neuropsychiatric presentations at initial visit between Black and White individuals with FTD. Future work must address racial disparities in FTD and their underlying social determinants as well as the lack of representation of non-White individuals in nationally representative neurodegenerative disease registries in order identify appropriate interventions.

OBJECTIVE: Grit is a noncognitive trait that has been shown to increase monotonically throughout adulthood and predict late-life cognitive performance. Less is known about the relation between grit and successful aging in older adults. PARTICIPANTS AND METHODS: Participants over 55-years-old (N = 185) completed a series of self-report surveys assessing demographics, grit (Short Grit Scale; Grit-S), physical and emotional functioning (Medical Outcomes Study Short Form Health Survey; SF-36), and changes in cognitive functioning (Everyday Cognition; ECog). Principal component analysis of the Grit-S was conducted, and then Pearson product moment correlations and multiple linear regressions were used to assess the relations between grit, age, and measures of successful aging. RESULTS: Grit showed no association with age, even after controlling for education. Grit total score was positively associated with a variety of successful aging variables (SF-36; physical, emotional, and social functioning, energy, general health; all p’s

The remnants of kilometre-sized solidified magma bodies exposed in volcanic areas are the product of magma accumulation beneath active volcanoes. These magma bodies can have formed over time spans ranging from months to hundreds of thousands of years, and some have triggered unrest and fed eruptions at the volcano surface. Here, we focus on melt-dominated magma bodies in the upper crust, which represents a sub-volcanic magma-storage level overlying a deeper, likely mush-dominated, igneous plumbing system. Based on several examples in eastern Iceland, we present field observations, structural analyses, 3D reconstructions, and petrological and fabric analyses that shed light on (1) the growth of magma chambers during single, fast, or multiple, long-term, magma injection events and (2) the deformation of the surrounding host rock as a result of different styles of magma emplacement. Moreover, we present evidence for syn-emplacement eruptions from one of the field examples.We then discuss how field studies of solidified upper crustal magma chambers can inform the interpretation of volcanic unrest signals at active volcanoes. For instance, certain styles of magma emplacement create pronounced surface deformation and seismicity, while others may show initial seismicity that resembles dyke and/or sill emplacement but then allows for the emplacement of vast amounts of magma at shallow depth. This emplacement can likely happen without any significant surface deformation and with very little seismicity. Hence, solidified, exposed magma chambers that formed in the upper crust can provide valuable clues to improve eruption risk and volcano hazard assessment.

Late Life Depression (LLD) is associated with persistent cognitive dysfunction even after depression symptoms improve. The present study was designed to examine cognitive outcomes associated with the pattern of depression severity change during psychotherapy intervention for LLD.96 community-dwelling adults ages 65-91 with major depressive disorder completed 12 sessions of Problem-Solving Therapy at the University of California, San Francisco. Nonlinear trajectories of depression severity ratings using the Hamilton Depression Rating Scale were computed from multiple time points collected throughout the weekly psychotherapy intervention. Performance on measures of cognition (information processing speed, executive functioning, verbal learning, memory) was assessed at baseline and post-treatment. Linear mixed-effects models examined associations between nonlinear depression severity trajectories and post-treatment change in cognitive performance.Broadly, different patterns of depression change during treatment were associated with improved cognition post-treatment. Greater and more consistent interval improvements in depression ratings were differentially associated with improvements in aspects of verbal learning, memory, and executive function post-treatment, while no associations were found with information processing speed.The heterogeneity of depression trajectories associated with improved cognitive outcomes suggests that the temporal pattern of depression response may impact specific cognitive processes distinctly. Results suggest that use of nonlinear depression severity trajectories may help to elucidate complex associations between the time course of depression response and cognitive outcomes of psychotherapy in LLD. These findings have important implications for identifying treatment targets to enhance clinical and cognitive outcomes of psychotherapy in LLD.

Introduction The objective of this study is to evaluate the reliability and validity of the ReVeReTM word list recall test (RWLRT), which uses speech recognition, when administered remotely and unsupervised. Methods Prospective cohort study. Participants included 249 cognitively intact community dwelling older adults. Measures included clinician administered neuropsychological assessments at baseline and unsupervised remotely administered tests of cognition from six time-points over sixmonths. Results The RWLRT showed acceptable validity. Reliability coefficients varied across time points, with poor reliability between times 1 and 2 and fair-to-good reliability across the remaining five testing sessions. Practice effects were observed with repeated administration as expected. Discussion Unsupervised computerized tests of cognition, particularly word list learning and memory tests that use speech recognition, have significant potential for large scale early detection and long-term tracking of cognitive decline due to AD.

Background: Cognitive impairment (CI) is a key feature of late life depression (LLD), but the contribution of underlying neurodegenerative pathology remains unclear. Objective: To evaluate cognitive dysfunction in LLD relative to a sample of nondepressed (ND) older adults with matched levels of memory impairment and amyloid-β (Aβ) burden. Methods: Participants included 120 LLD and 240 ND older adults matched on age, education, sex, Mini-Mental State Exam, mild cognitive impairment diagnosis, and PET Aβ burden. Results: LLD showed higher rates of impairment relative to ND with 54.6% of the LLD sample demonstrating impairment in at least one cognitive domain compared to 42.9% of controls (H = 7.13, p = 0.008). LLD had poorer performance and higher rates of impairment on Rey Auditory Verbal Learning Test learning and memory compared to controls. In the overall sample, Aβ positivity was associated with worse performance on Logical Memory I (p = 0.044), Logical Memory II (p = 0.011), and Trail Making Test –B (p = 0.032), and APOE ɛ4 genotype was associated with worse performance on Logical Memory I (p = 0.022); these relationships did not differ between LLD and ND. Conclusion: LLD showed higher rates of CI driven by focal deficits in verbal learning and memory. Alzheimer’s disease (AD) biomarkers were associated with worse performance on timed set-shifting and story learning and memory, and these relationships were not impacted by depression status. These findings suggest that AD may account for a portion of previously reported multi-domain CI in LLD and highlight the potential for AD to confound studies of cognition in LLD.

Understanding the processes that drive explosive-effusive transitions during large silicic eruptions is crucial to hazard mitigation. Conduit models usually treat magma ascent and degassing as a gradual, unidirectional progression from bubble nucleation through magmatic fragmentation. However, there is growing evidence for the importance of bi-directional clastogenic processes that sinter fragmented materials into coherent clastogenic magmas. Bombs that were ejected immediately before the first emergence of lava in the 2011–2012 eruption at Cordón Caulle volcano (Chile) are texturally heterogeneous composite assemblages of welded pyroclastic material. Although diverse in density and appearance, SEM and X-ray tomographic analysis show them all to have been formed by multi-generational viscous sintering of fine ash. Sintering created discrete clasts ranging from obsidian to pumice and formed a pervasive clast-supporting matrix that assembled these clasts into a conduit-sealing plug. An evaluation of sintering timescales reveals texturally disparate bomb components to represent only minutes of difference in residence time within the conduit. Permeability modelling indicates that the plug was an effective conduit seal, with outgassing potential—even from high-porosity regions—being limited by the inability of gas to flow across tendrils of densely sintered inter-clast matrix. Contrary to traditional perspectives, declining expressions of explosivity at the surface need not be preceded or accompanied by a decline in fragmentation efficiency. Instead, they result from tips in balance between the opposing processes of fragmentation and sintering that occur in countless cycles within volcanic conduits. These processes may be particularly enhanced at silicic fissure volcanoes, which have laterally extensive subsurface plumbing systems that require complex magma ascent pathways. The textures investigated here reveal the processes occurring within silicic fissures to be phenomenologically identical to those that have been inferred to occur in tuffisite veins: silicic conduits are essentially supersized examples of edifice-penetrating tuffisites.

Knut och Alice Wallenbergs Stiftelse (Knut and Alice Wallenberg Foundation). Grant Number: KAW 2017.0153 Royal Swedish Academy of Sciences (KVA). Grant Number: GS2019–0024 Center of Natural Hazards and Disaster Science. Although it is widely accepted that shallow silicic magma reservoirs exist, and can feed eruptions, their dynamics and longevity are a topic of debate. Here, we use field mapping, geochemistry, 3D pluton reconstruction and a thermal model to investigate the assembly and eruptive history of the shallow Reyoarartindur Pluton, southeast Iceland. Primarily, the exposed pluton is constructed of a single rock unit, the Main Granite (69.9-77.7 wt.% SiO2). Two further units are locally exposed as enclaves at the base of the exposure, the Granite Enclaves (67.4-70.2 wt.% SiO2), and the Quartz Monzonite Enclaves (61.8-67.3 wt.% SiO2). Geochemically, the units are related and were likely derived from the same source reservoir. In 3D, the pluton has a shape characterized by flat roof segments that are vertically offset and a volume of >2.5 km3. The pluton roof is intruded by dikes from the pluton, and in two locations displays depressions associated with large dikes. Within these particular dikes the rock is partially to wholly tuffisitic, and rock compositions range from quartz monzonite to granite. We interpret these zones as eruption-feeding conduits from the pluton. A lack of cooling contacts throughout the pluton indicates rapid magma emplacement and a thermal model calculates the top 75 m would have rheologically locked up within 1,000 years. Hence, we argue that the Reyoarartindur Pluton was an ephemeral part of the wider plumbing system that feeds a volcano, and that timeframes from emplacement to eruption were rapid. Publisher PDF

Recent eruptions such as the Kilauea 2018 (fissure) eruption on Hawaii are the result of magma intruding into Earth’s crust and ascending towards the surface. Magma is dominantly transported, through the shallow crust in form of vertical sheet intrusions (dykes). Even though dyke propagation and emplacement has been monitored with geodetic and geophysical methods, direct observations of subsurface intrusion processes remain inaccessible due to the hazardous nature of active volcanic and igneous systems. Therefore, we studied the extinct and eroded volcanic system of the Chachahuén volcanic complex (CVC) in Argentina to investigate the scale and physical mechanisms of magma transport in volcanic and igneous plumbing systems.The Chachahuén volcanic complex is located in the northern part of the Neuquén Basin, east of the southern volcanic zone (SVZ) of the Andes. A decline in volcanic activity during the Quaternary and erosion have exposed the shallow part of the Miocene CVC’s plumbing system, including two major vertical sheet intrusions: (1) the Great Dyke and (2) the Sosa Dyke.The objective of this ongoing study is to characterize the mechanisms of magma transport within the two exposed dykes to better understand the physical processes during their emplacement. We apply a multiscale approach combining field work and state-of-the-art analytical techniques, i.e., drone/ground-based photogrammetry, Fourier Transform Infrared Spectroscopy (FTIR), Electron Backscatter Diffraction (EBSD) and Anisotropy of Magnetic Susceptibility (AMS), with traditional geological methods, i.e., microstructural analysis and igneous petrology. Thus, we can investigate the effect of magma rheology (small-scale) on the outer shape and morphology of the dykes (large-scale).Our results using high-resolution 3D outcrop models show a segmentation of the investigated dykes. Each of these dyke segments shows blunt ends. This suggests either the emplacement of a highly viscous magma or a weak brittle host rock. Flow features identified with AMS analysis indicate a dominantly lateral magma transport within the dykes. To estimate the magma viscosity during emplacement FTIR (H2O content of the initial melt), and microstructural analysis (for crystallinity) are performed at the moment. These analyses in combination with a map of the host rock and, the dyke morphologies, will help to characterize the dominantly controlling mechanism(s) of magma emplacements in the CVC. Finally, the new findings from this project will contribute to the general understanding on how the physical properties of the magma affect the shape of magma bodies and magma flow in the Earth’s shallow crust.

Background We evaluated the role of cortical amyloid deposition as a factor contributing to memory dysfunction and increased risk of dementia associated with late-life depression (LLD). Methods A total of 119 older adult participants with a current diagnosis of major depression (LLD) from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) Depression Project study and 119 nondepressed (ND) cognitively unimpaired participants matched on age, sex, and APOE genotype were obtained from the ADNI database. Results Thirty-three percent of LLD participants met ADNI criteria for mild cognitive impairment. Compared with ND individuals, the LLD group exhibited less global amyloid beta (Aβ) accumulation (p = .05). The proportion of amyloid positivity in the LLD group was 19.3% compared with 31.1% for the ND participants (p = .02). Among LLD participants, global Aβ was not associated with lifetime number of depressive episodes, lifetime length of depression, length of lifetime selective serotonin reuptake inhibitor use, or lifetime length of untreated depression (p > .21 for all). Global Aβ was associated with worse memory performance (p = .05). Similar results were found in secondary analyses restricting comparisons to the cognitively unimpaired LLD participants as well as when comparing the LLD group with an ND group that included participants with mild cognitive impairment. Conclusions Contrary to expectation, the LLD group showed less Aβ deposition than the ND group and Aβ deposition was not associated with depression history characteristics. Aβ was associated with memory, but this relationship did not differ between LLD and ND. Our results suggest that memory deficits and accelerated cognitive decline reported in previous studies of LLD are not due to greater cortical Aβ accumulation.

Objective Competitive Queuing (CQ) models of memory for serial order comprise two layers: parallel planning where target items are activated and competitive choice where serial order is specified. The application of CQ models regarding healthy and pathological aging has received little attention. Method Participants included patients with Alzheimer’s disease (AD; n = 26), vascular dementia (VaD; n = 29), and healthy controls (HC; n = 35). Memory for serial order in the visual domain was assessed using the Object Span Task, where participants briefly viewed then drew a sequence of four figures. Percent correct and total errors (omissions, intrusions, repetitions, transpositions) were computed for each serial position. Results Significant primacy effects were detected in each group. AD and VaD participants were less accurate and showed more omission and between-trial repetition errors than HC (HC < AD = VaD, p < .05). VaD participants produced more transposition and intrusion errors than the AD and HC groups (HC < AD < VaD, p < .05). A group × position interaction was significant for omissions (p < .05), with AD and VaD participants producing more omissions in later serial positions (SP1 < SP2 < SP3 < SP4, all p values < .05). Conclusions Analysis of accuracy and errors by serial position identified unique patterns of performance across groups that suggest involvement of distinct layers of response activation and selection. Serial order difficulties in AD may be due to weakened activation of task items affecting later serial positions, whereas poor performance in VaD may be due to weakened activation plus interference from extraneous stimuli at all serial positions.

Introduction Late life depression (LLD) is a common and heterogeneous condition that is associated with increased disability, cognitive impairment, and all-cause mortality in older adults. Anti-depressant medication and psychotherapy have been identified as effective treatments for LLD, though as many as 50% of patients do not respond to treatment. Several clinical (age, age of MDD onset, MDE severity, anxiety, perceived stress, social support, sleep quality) and cognitive (executive dysfunction, global cognitive impairment) factors have been identified as predictors of response to anti-depressant treatment. Less is known about predictors of psychotherapy treatment response in LLD, but cognitive dysfunction has been linked to poor treatment outcomes and may negatively impact the effectiveness of behavioral interventions that are subserved by various cognitive processes. Methods Participants included 83 individuals with LLD (HAM-D > 17) enrolled in a manualized 12-week psychotherapy with a licensed psychologist. All participants completed diagnostic interviews, comprehensive neuropsychological assessments and clinical evaluations before and after treatment. Separate multiple linear regression models were used to assess independent effects of baseline MDD features (age at onset, severity, treatment history, frequency and chronicity of MDEs), related clinical factors (comorbid anxiety and hoarding behaviors, perceived stress and health, social support, sleep disturbance), and cognitive performance (global cognition, executive functioning, episodic memory, processing speed, language, visuospatial skills, motor speed and dexterity) as predictors of treatment response, with percent change in HAM-D as the outcome variable. Cognitive performance was grouped by domain using composite Z-scores based on group means and standard deviations (all Chronbach's a's > .70). Results Forty-five percent (n=38) of participants showed treatment response (>50% reduction in HAM-D post-treatment). Responders were significantly younger (mean age = 69.76) than non-responders (mean age = 73.11, t = 7.10, p = .009). Level of education, gender distribution, and baseline depression characteristics (severity, length of episode, anti-depressant use) were equivalent (all p’s > .05). depression features accounted for 23.9% of the variance in HAM-D change, and showed a trend toward significance for older age of MDD onset associated with increased treatment response (t = 1.85, b = 0.38, p = .06) after accounting for age (t = 2.10, b = 0.31, p = .017). Non-depression clinical features accounted for 31.2% of the variance in HAM-D change, and greater sleep disturbance was associated with worse treatment response after accounting for age (t = 2.53, b = 0.34, p = .015). Cognitive performance accounted for 10.1% of the variance in HAM-D change, with no significant predictors after accounting for age (t = 2.36, b = 0.25, p = .021 Conclusions Our findings show that older age and sleep disturbance predict poorer response to treatment with 12 weeks of psychotherapy in a sample of individuals with LLD. Older age may negatively impact treatment response via increased risk for underlying neurodegenerative pathologies that are not affected by treatment with psychotherapy or medication. Similarly, sleep dysfunction in older adults has been implicated in the pathogenesis of Alzheimer's disease and related dementias and may reflect the presence of an underlying neurodegenerative process that is not targeted by psychiatric intervention. A preliminary exploration of cognitive factors suggests that cognitive dysfunction may play a more limited role in response to psychotherapeutic relative to pharmacologic intervention. Future research should assess the effect of neurodegenerative pathology on response to treatment with psychotherapy and medication in LLD. Funding This project was supported by the National Institute of Mental Health grant 1R01MH101472.

The structures and textures preserved in lava domes reflect underlying magmatic and eruptive processes, and may provide evidence of how eruptions initiate and evolve. This study explores the remarkable cycles in lava extrusion style produced between 1922 and 2012 at the Santiaguito lava dome complex, Guatemala. By combining an examination of eruptive lava morphologies and textures with a review of historical records, we aim to constrain the processes responsible for the range of erupted lava type and morphologies. The Santiaguito lava dome complex is divided into four domes (El Caliente, La Mitad, El Monje, El Brujo), containing a range of proximal structures (e.g., spines) from which a series of structurally contrasting lava flows originate. Vesicular lava flows (with a'a like, yet non-brecciated flow top) have the highest porosity with interconnected spheroidal pores and may transition into blocky lava flows. Blocky lava flows are high volume and texturally variable with dense zones of small tubular aligned pore networks and more porous zones of spheroidal shaped pores. Spines are dense and low volume and contain small skeletal shaped pores, and subvertical zones of sigmoidal pores. We attribute the observed differences in pore shapes to reflect shallow inflation, deflation, flattening, or shearing of the pore fraction. Effusion rate and duration of the eruption define the amount of time available for heating or cooling, degassing and outgassing prior to and during extrusion, driving changes in pore textures and lava type. Our new textural data when reviewed with all the other published data allow a cyclic model to be developed. The cyclic eruption models are influenced by viscosity changes resulting from (1) initial magmatic composition and temperature, and (2) effusion rate which in turn affects degassing, outgassing and cooling time in the conduit. Each lava type presents a unique set of hazards and understanding the morphologies and dome progression is useful in hazard forecasting.

Climate change, globalization, urbanization, social isolation, and increased interconnectedness between physical, human, and technological systems pose major challenges to disaster risk reduction (DRR). Subsequently, economic losses caused by natural hazards are increasing in many regions of the world, despite scientific progress, persistent policy action, and international cooperation. We argue that these dramatic figures call for novel scientific approaches and new types of data collection to integrate the two main approaches that still dominate the science underpinning DRR: the hazard paradigm and the vulnerability paradigm. Building from these two approaches, here we propose a research framework that specifies the scope of enquiry, concepts, and general relations among phenomena. We then discuss the essential steps to advance systematic empirical research and evidence-based DRR policy action. Plain Language Summary The recent deadly earthquake in Iran-Iraq has been yet another reminder of the topicality of natural hazards, and it has come just after an unprecedented series of catastrophic events, including the extensive flooding in South Asia and the string of devastating hurricanes in the Americas. He we identify three main puzzles in the nexus of natural hazards and vulnerabilities, and demonstrate how novel approaches are needed to solve them with reference to a flood risk example. Specifically, we show how a new research framework can guide systematic data collections to advance the fundamental understanding of socionatural interactions, which is an essential step to improve the development of policies for disaster risk reduction.

Cognitive functioning, particularly executive functioning, is a strong predictor of functional outcomes in people with schizophrenia. Cognitive remediation has been shown to improve specific cognitive processes, but adjunctive interventions are required for meaningful gains in adaptive functioning, particularly in people with chronic illness. This study examined whether (and how) environmental adaptations, used without training, may circumvent cognitive difficulties and facilitate everyday task performance in individuals with chronic schizophrenia. Forty-two individuals with chronic schizophrenia/schizoaffective disorder were administered cognitive measures and two versions of the Naturalistic Action Test (NAT)—a standard version (ST-NAT), and a user-centered version (UC-NAT) that incorporated environmental adaptations designed to facilitate task performance. The NAT conditions were counterbalanced across participants. Analyses compared performance between the NAT versions and examined the cognitive correlates of each NAT condition. Individuals with schizophrenia made fewer errors on the UC-NAT as compared to the ST-NAT; this between-group difference was significant for all error types. Compared to the ST-NAT, the UC-NAT performance was not significantly associated with an executive function measure of planning. Environmental adaptations may be implemented without extensive training to improve everyday action in individuals with chronic schizophrenia. Environmental adaptations that reduce planning demands may be most effective in this population. (JINS, 2015, 21, 319–329)

Various psychological assets have been shown to protect against late-life cognitive impairment by promoting cognitive reserve. While factors such as educational attainment and IQ are well-established contributors to cognitive reserve, non-cognitive factors, such as grit, have not been studied in this regard. We examined the contribution of adolescent grit, indexed by high school class rank controlling for IQ, to late-life cognition and its decline among approximately 4,000 participants in the Wisconsin Longitudinal Study, a random sample of high school graduates followed from 1957 to 2011. Adolescent grit significantly predicted both immediate and delayed memory at ages 64 and 71, over and above the contribution of IQ. While the relative contributions of IQ and grit to immediate memory were comparable, grit was a stronger predictor of delayed memory. Cognitive reserve has non-cognitive, as well as cognitive, components.

Terrestrial volcanic eruptions are the consequence of magmas ascending to the surface of the Earth. This ascent is driven by buoyancy forces, which are enhanced by bubble nucleation and growth (vesiculation) that reduce the density of magma1. The development of vesicularity also greatly reduces the ‘strength’ of magma2, a material parameter controlling fragmentation and thus the explosive potential of the liquid rock3. The development of vesicularity in magmas has until now been viewed (both thermodynamically and kinetically) in terms of the pressure dependence of the solubility of water in the magma, and its role in driving gas saturation, exsolution and expansion during decompression. In contrast, the possible effects of the well documented negative temperature dependence of solubility of water in magma has largely been ignored. Recently, petrological constraints have demonstrated that considerable heating of magma may indeed be a common result of the latent heat of crystallization4 as well as viscous5,6 and frictional7 heating in areas of strain localization. Here we present field and experimental observations of magma vesiculation and fragmentation resulting from heating (rather than decompression). Textural analysis of volcanic ash from Santiaguito volcano in Guatemala reveals the presence of chemically heterogeneous filaments hosting micrometre-scale vesicles. The textures mirror those developed by disequilibrium melting induced via rapid heating during fault friction experiments, demonstrating that friction can generate sufficient heat to induce melting and vesiculation of hydrated silicic magma. Consideration of the experimentally determined temperature and pressure dependence of water solubility in magma reveals that, for many ascent paths, exsolution may be more efficiently achieved by heating than by decompression. We conclude that the thermal path experienced by magma during ascent strongly controls degassing, vesiculation, magma strength and the effusive–explosive transition in volcanic eruptions.

“Molecular imaging” elucidates discrete biological processes, including levels of cerebral proteins, measures of axonal and myelin integrity and biochemical pathways. Positron Emission Tomography (PET) has been used to demonstrate an abnormal deposition of neuritic plaques and the presence of neurofibrillar tangles in Alzheimer’s disease. Recent PET studies have shown similar pathophysiology in geriatric depression. Diffusion Tensor Imaging (DTI) has been used to detect microstructural brain changes in white matter. These findings have been associated with disease severity, treatment response/resistance and cognitive impairment in late-life depression. Magnetic Resonance Spectroscopy (MRS) can be used to quantify the regional or global concentrations of cerebral proton and phosphorus biochemical markers. This methodology may yield insight into facets of neuropsychiatric disorders including neurotransmission, bioenergetic metabolism and cell membrane integrity. This chapter serves as an introduction to these neuroimaging techniques and their application in studying geriatric neuropsychiatric illnesses.