Offsetting of CO₂ emissions by air capture in mine tailings at the Mount Keith Nickel Mine, Western Australia: Rates, controls and prospects for carbon neutral mining

The hydrated Mg-carbonate mineral, hydromagnesite [Mg₅(CO₃)₄(OH)₂•4H₂O], precipitates within mine tailings at the Mount Keith Nickel Mine, Western Australia as a direct result of mining operations. We have used quantitative mineralogical data and δ¹³C, δ¹⁸O and F¹⁴C isotopic data to quantify the amount of CO₂fixation and identify carbon sources. Our radiocarbon results indicate that at least 80% of carbon stored in hydromagnesite has been captured from the modern atmosphere. Stable isotopic results indicate that dissolution of atmospheric CO₂ into mine tailings water is kinetically limited, which suggests that the current rate of carbon mineralization could be accelerated. Reactive transport modeling is used to describe the observed variation in tailings mineralogy and to estimate rates of CO₂ fixation. Based on our assessment, approximately 39,800 t/yr of atmospheric CO₂ are being trapped and stored in tailings at Mount Keith. This represents an offsetting of approximately 11% of the mine's annual greenhouse gas emissions. Thus, passive sequestration via enhanced weathering of mineral waste can capture and store a significant amount of CO₂. Recommendations are made for changes to tailings management and ore processing practices that have potential to accelerate carbonation of tailings and further reduce or completely offset the net greenhouse gas emissions at Mount Keith and many other mines

Extraordinarily high biomass benthic community on Southern Ocean seamounts

We describe a previously unknown assemblage of seamount-associated megabenthos that has by far the highest peak biomass reported in the deep-sea outside of vent communities. The assemblage was found at depths of 2-2.5 km on rocky geomorphic features off the southeast coast of Australia, in an area near the Sub-Antarctic Zone characterised by high rates of surface productivity and carbon export to the deep-ocean. These conditions, and the taxa in the assemblage, are widely distributed around the Southern mid-latitudes, suggesting the high-biomass assemblage is also likely to be widespread. The role of this assemblage in regional ecosystem and carbon dynamics and its sensitivities to anthropogenic impacts are unknown. The discovery highlights the lack of information on deep-sea biota worldwide and the potential for unanticipated impacts of deep-sea exploitation

Self-reported intake of high-fat and high-sugar diet is not associated with cognitive stability and flexibility in healthy men

Animal studies indicate that a high-fat/high-sugar diet (HFS) can change dopamine signal transmission in the brain, which could promote maladaptive behavior and decision-making. Such diet-induced changes may also explain observed alterations in the dopamine system in human obesity. Genetic variants that modulate dopamine transmission have been proposed to render some individuals more prone to potential effects of HFS. The objective of this study was to investigate the association of HFS with dopamine-dependent cognition in humans and how genetic variations might modulate this potential association. Using a questionnaire assessing the self -reported consumption of high-fat/high-sugar foods, we investigated the association with diet by recruiting healthy young men that fall into the lower or upper end of that questionnaire (low fat/sugar group: LFS, n = 45; high fat/sugar group: HFS, n = 41) and explored the interaction of fat and sugar consumption with COMT Va1158Met and Taq1A genotype. During functional magnetic resonance imaging (fMRI) scanning, male partici-pants performed a working memory (WM) task that probes distractor-resistance and updating of WM repre-sentations. Logistic and linear regression models revealed no significant difference in WM performance between the two diet groups, nor an interaction with COMT Va1t58Met or Tag1A genotype. Neural activation in task -related brain areas also did not differ between diet groups. Independent of diet group, higher BMI was associ-ated with lower overall accuracy on the WM task. This cross-sectional study does not provide evidence for diet -related differences in WM stability and flexibility in men, nor for a predisposition of COMT Va1158Met or Tag1A genotype to the hypothesized detrimental effects of an HFS diet. Previously reported associations of BMI with WM seem to be independent of HFS intake in our male study sample.Peer reviewe

Postpartum Anxiety and Infant-Feeding Outcomes: A Systematic Review

There is increasing evidence for the effect of postpartum anxiety (PPA) on maternal and infant health outcomes. Despite evidence linking suboptimal infant-feeding outcomes with other indices of maternal mental health, the relationship between PPA and infant feeding has not yet been reviewed. A systematic review with narrative synthesis was conducted to examine the relationship between PPA and infant-feeding outcomes. Electronic searches were performed using specific keywords (eg, “postnatal anxiet*”; “breastfeed*”). A hand search of selected journals and reference lists of included articles was then conducted. All studies were considered that provided information related to PPA and infant-feeding outcomes. One hundred and two studies were identified, of which 33 were eligible. Two authors independently extracted data including study design, participants, and results. Results indicated that women with symptoms of PPA are less likely to breastfeed exclusively and more likely to terminate breastfeeding earlier. Some evidence also suggests that those experiencing PPA are less likely to initiate breastfeeding and more likely to supplement with formula in the hospital. In those who do breastfeed, PPA reduces self-efficacy, increases breastfeeding difficulties, and may negatively affect breastfeeding behaviors and breast milk composition. Heterogeneous outcomes and methodological limitations somewhat limit the comparability of findings. However, in combination with a review linking depression with similar negative infant-feeding sequelae, the findings provide evidence for the effect of negative postpartum mood on breastfeeding. Additional support for breastfeeding mothers with PPA is warranted

Relative spins and excitation energies of superdeformed bands in 190Hg: Further evidence for octupole vibration

An experiment using the Eurogam Phase II gamma-ray spectrometer confirms the existence of an excited superdeformed (SD) band in 190Hg and its very unusual decay into the lowest SD band over 3-4 transitions. The energies and dipole character of the transitions linking the two SD bands have been firmly established. Comparisons with RPA calculations indicate that the excited SD band can be interpreted as an octupole-vibrational structure.Comment: 12 pages, latex, 4 figures available via WWW at http://www.phy.anl.gov/bgo/bc/hg190_nucl_ex.htm