Smarter through group living: A response to Smulders

This is the author accepted manuscript. The final version is available from Springer via the DOI in this recordWe recently identified a strong, positive relationship between group size and individual cognitive performance, and a strong, positive relationship between female cognitive performance and reproductive success (Ashton, Ridley, Edwards, & Thornton in Nature, 554, 364–367, 2018). An opinion piece by Smulders (Learning & Behavior, https://doi.org/10.3758/s13420-018-0335-0, 2018) raised the interesting notion that these patterns may be underlined by motivational factors. In this commentary, we highlight why none of the available data are consistent with this explanation, but instead support the argument that the demands of group living influence cognitive development, with knock-on consequences for fitness

Plasma REST: A novel candidate biomarker of Alzheimer\u27s disease is modified by psychological intervention in an at-risk population

The repressor element 1-silencing transcription (REST) factor is a key regulator of the aging brain’s stress response. It is reduced in conditions of stress and Alzheimer’s disease (AD), which suggests that increasing REST may be neuroprotective. REST can be measured peripherally in blood plasma. Our study aimed to (1) examine plasma REST levels in relation to clinical and biological markers of neurodegeneration and (2) alter plasma REST levels through a stress-reduction intervention—mindfulness training. In study 1, REST levels were compared across the following four well-characterized groups: healthy elderly (n=65), mild cognitive impairment who remained stable (stable MCI, n=36), MCI who later converted to dementia (converter MCI, n=29) and AD (n=65) from the AddNeuroMed cohort. REST levels declined with increasing severity of risk and impairment (healthy elderly>stable MCI>converter MCI>AD, F=6.35, P<0.001). REST levels were also positively associated with magnetic resonance imaging-based hippocampal and entorhinal atrophy and other putative blood-based biomarkers of AD (Ps<0.05). In study 2, REST was measured in 81 older adults with psychiatric risk factors for AD before and after a mindfulness-based stress reduction intervention or an education-based placebo intervention. Mindfulness-based training caused an increase in REST compared with the placebo intervention (F=8.57, P=0.006), and increased REST was associated with a reduction in psychiatric symptoms associated with stress and AD risk (Ps<0.02). Our data confirm plasma REST associations with clinical severity and neurodegeneration, and originally, that REST is modifiable by a psychological intervention with clinical benefit

High Throughput Synthesis and Screening of Oxygen Reduction Catalysts in the MTiO₃ (M = Ca, Sr, Ba) Perovskite Phase Diagram

A library of 66 perovskite BaxSryCazTiO3 (x + y + z = 1) samples (ca. three grams per sample) was made in ca. 14 h using a high-throughput continuous hydrothermal flow synthesis system. The as-synthesized samples were collected from the outlet of the process and then cleaned and freeze-dried before being evaluated individually as oxygen reduction catalysts using a rotating disk electrode testing technique. To establish any correlations between physical and electrochemical characterization data, the as-synthesized samples were investigated using analytical methods including BET surface area, powder X-ray diffraction (PXRD) and in selected cases, transmission electron microscopy (TEM). The aforementioned approach was validated as being able to quickly identify oxygen reduction catalysts from new libraries of electrocatalysts

An intraspecific appraisal of the social intelligence hypothesis

This is the final version. Available on open access from the Royal Society via the DOI in this recordData accessibility: This article has no additional dataThe prevailing hypotheses for the evolution of cognition focus on either the demands associated with group living (the social intelligence hypothesis (SIH)) or ecological challenges such as finding food. Comparative studies testing these hypotheses have generated highly conflicting results; consequently, our understanding of the drivers of cognitive evolution remains limited. To understand how selection shapes cognition, research must incorporate an intraspecific approach, focusing on the causes and consequences of individual variation in cognition. Here, we review the findings of recent intraspecific cognitive research to investigate the predictions of the SIH. Extensive evidence from our own research on Australian magpies (Cracticus tibicen dorsalis), and a number of other taxa, suggests that individuals in larger social groups exhibit elevated cognitive performance and, in some cases, elevated reproductive fitness. Not only do these findings demonstrate how the social environment has the potential to shape cognitive evolution, but crucially, they demonstrate the importance of considering both genetic and developmental factors when attempting to explain the causes of cognitive variation. This article is part of the theme issue ‘Causes and consequences of individual differences in cognitive abilities’.Australian Research CouncilBiotechnology and Biological Sciences Research Council (BBSRC)Human Frontiers Research Progra

Plasma REST: a novel candidate biomarker of Alzheimer's disease is modified by psychological intervention in an at-risk population.

The repressor element 1-silencing transcription (REST) factor is a key regulator of the aging brain's stress response. It is reduced in conditions of stress and Alzheimer's disease (AD), which suggests that increasing REST may be neuroprotective. REST can be measured peripherally in blood plasma. Our study aimed to (1) examine plasma REST levels in relation to clinical and biological markers of neurodegeneration and (2) alter plasma REST levels through a stress-reduction intervention-mindfulness training. In study 1, REST levels were compared across the following four well-characterized groups: healthy elderly (n=65), mild cognitive impairment who remained stable (stable MCI, n=36), MCI who later converted to dementia (converter MCI, n=29) and AD (n=65) from the AddNeuroMed cohort. REST levels declined with increasing severity of risk and impairment (healthy elderly>stable MCI>converter MCI>AD, F=6.35, P<0.001). REST levels were also positively associated with magnetic resonance imaging-based hippocampal and entorhinal atrophy and other putative blood-based biomarkers of AD (Ps<0.05). In study 2, REST was measured in 81 older adults with psychiatric risk factors for AD before and after a mindfulness-based stress reduction intervention or an education-based placebo intervention. Mindfulness-based training caused an increase in REST compared with the placebo intervention (F=8.57, P=0.006), and increased REST was associated with a reduction in psychiatric symptoms associated with stress and AD risk (Ps<0.02). Our data confirm plasma REST associations with clinical severity and neurodegeneration, and originally, that REST is modifiable by a psychological intervention with clinical benefit

Continuous Hydrothermal Synthesis of Metal Germanates (M₂GeO₄; M=Co, Mn, Zn) for High-Capacity Negative Electrodes in Li-Ion Batteries

Nanosized metal germanates (M2GeO4; M = Co, Mn, Zn) are synthesized using a continuous hydrothermal flow synthesis process for the first time. The electrochemical properties of all samples as active materials for negative electrodes in Li‐ion half cells are explored. The galvanostatic and potentiodynamic testing is conducted in the potential range of 3.00–0.05 V versus Li/Li+. The results suggest that both alloying and conversion reactions associated with Ge contribute to the stored charge capacity; Zn2GeO4 shows a high specific capacity of 600 mAh g−1 (ten cycles at 0.1 A g−1) due to alloying and conversion reactions for both Ge and Zn. Mn2GeO4 is studied for the first time as a potential negative electrode material in a Li‐ion half cell; an excellent specific charge capacity of 510 mAh g−1 (10 cycles per 0.1 A g−1) is obtained with a significant contribution to charge arising from the conversion reaction of Mn to MnO upon delithiation. In contrast, Co2GeO4 only shows a specific capacity of 240 mAh g−1, after ten cycles at the same current rate, which suggests that cobalt has little or no benefit for enhancing stored charge in germanate

Multiple diffusion pathways in LixNi0.77Co0.14Al0.09O2 (NCA) Li-ion battery cathodes

Experimental evidence for the presence of two computationally theorised diffusion pathways, namely the oxygen dumbbell hop (ODH) and tetrahedral site hop (TSH), has been given for the first time by muon spin relaxation (µSR) on sub-stoichiometric LixNi0.77Co0.14Al0.09O2. µSR has proven to be a powerful tool that is able to discriminate between diffusion pathways that occur on different timescales on a local level, where bulk electrochemical techniques cannot. Whereas the estimated values of DLi at lithium concentrations of 0.87 and 0.71 were found to be on the order of 10-11 by electrochemical impedance spectroscopy, contributions to diffusion from ODH and TSH were determined to be on the order of 10-11 and 10-10 cm2 s-1, and a factor of four decrease in Ea for both samples, in excellent agreement with theoretical calculations on related compounds. Rietveld refinement of both X-ray and neutron diffraction data was also used to interrogate the local structure of the materials where no contribution from Li+/Ni2+ cation mixing was observed

Quantifying Spatio-temporal risk of Harmful Algal Blooms and their impacts on bivalve shellfish mariculture using a data-driven modelling approach

Harmful algal blooms (HABs) intoxicate and asphyxiate marine life, causing devastating environmental and socio-economic impacts, costing at least $8bn/yr globally. Accumulation of phycotoxins from HAB phytoplankton in filter-feeding shellfish can poison human consumers, prompting harvesting closures at shellfish production sites. To quantify long-term intoxication risk from Dinophysis HAB species, we used historical HAB monitoring data (2009–2020) to develop a new modelling approach to predict Dinophysis toxin concentrations in a range of bivalve shellfish species at shellfish sites in Western Scotland, South-West England and Northern France. A spatiotemporal statistical modelling framework was developed within the Generalized Additive Model (GAM) framework to quantify long-term HAB risks for different bivalve shellfish species across each region, capturing seasonal variations, and spatiotemporal interactions. In all regions spatial functions were most important for predicting seasonal HAB risk, offering the potential to inform optimal siting of new shellfish operations and safe harvesting periods for businesses. A 10-fold cross-validation experiment was carried out for each region, to test the models’ ability to predict toxin risk at harvesting locations for which data were withheld from the model. Performance was assessed by comparing ranked predicted and observed mean toxin levels at each site within each region: the correlation of ranks was 0.78 for Northern France, 0.64 for Western Scotland, and 0.34 for South-West England, indicating our approach has promise for predicting unknown HAB risk, depending on the region and suitability of training data

Quantifying habitat provisioning at macroalgal cultivation sites.

Macroalgal cultivation is expanding rapidly, and promises to contribute significantly towards future food and energy security, sustainable livelihoods, ecosystem services and habitat provisioning for a range of associated organisms globally. Habitat provisioning underpins biodiversity and ecosystem structure and functioning, supports many ecosystem services and has possible benefits to other marine industries, including enhancement of commercial fish stocks. In macroalgal cultivation, however, only recently has habitat provisioning started to be assessed at a local scale (within a farm's footprint) and with a range of different approaches. This review evaluates techniques used to quantify habitat provisioning in and around macroalgal cultivation sites, for species ranging from microorganisms to megafauna, and outlines recommendations to enable a more comprehensive ecological valuation of macroalgal cultivation in the future. The majority of information on biodiversity associated with macroalgal cultivation is associated with quantifying biofouling or pest organisms, rather than the contribution of colonising species to healthy ecosystem functioning. We suggest how better monitoring of macroalgal cultivation could enable an ecosystem approach to aquaculture (EAA) in the future. To achieve this, we highlight the need for standardised and robust methods for quantifying habitat provisioning that will enable assessment and monitoring of macroalgal cultivation sites of varying scales and within different regions and environmental settings. Increased evidence for the potential habitat value of macroalgal cultivation sites will help inform and shape marine legislation, licencing and certification for macroalgal farmers and potentially reduce marine user conflicts, helping the industry to continue to grow sustainably using EAA

Characteristics of C-4 photosynthesis in stems and petioles of C-3 flowering plants

Most plants are known as C-3 plants because the first product of photosynthetic CO2 fixation is a three-carbon compound. C-4 plants, which use an alternative pathway in which the first product is a four-carbon compound, have evolved independently many times and are found in at least 18 families. In addition to differences in their biochemistry, photosynthetic organs of C-4 plants show alterations in their anatomy and ultrastructure. Little is known about whether the biochemical or anatomical characteristics of C-4 photosynthesis evolved first. Here we report that tobacco, a typical C-3 plant, shows characteristics of C-4 photosynthesis in cells of stems and petioles that surround the xylem and phloem, and that these cells are supplied with carbon for photosynthesis from the vascular system and not from stomata. These photosynthetic cells possess high activities of enzymes characteristic of C-4 photosynthesis, which allow the decarboxylation of four-carbon organic acids from the xylem and phloem, thus releasing CO2 for photosynthesis. These biochemical characteristics of C-4 photosynthesis in cells around the vascular bundles of stems of C-3 plants might explain why C-4 photosynthesis has evolved independently many times