Tropical savannas are a globally extensive biome prone to rapid vegetation change in response to changing environmental conditions. Via a meta‐analysis, we quantified savanna woody vegetation change ...spanning the last century. We found a global trend of woody encroachment that was established prior the 1980s. However, there is critical regional variation in the magnitude of encroachment. Woody cover is increasing most rapidly in the remaining uncleared savannas of South America, most likely due to fire suppression and land fragmentation. In contrast, Australia has experienced low rates of encroachment. When accounting for land use, African savannas have a mean rate annual woody cover increase two and a half times that of Australian savannas. In Africa, encroachment occurs across multiple land uses and is accelerating over time. In Africa and Australia, rising atmospheric CO2, changing land management and rainfall are likely causes. We argue that the functional traits of each woody flora, specifically the N‐fixing ability and architecture of woody plants, are critical to predicting encroachment over the next century and that African savannas are at high risk of widespread vegetation change.
There is evidence for differential stability in personality trait differences, even over decades. The authors used data from a sample of the Scottish Mental Survey, 1947 to study personality ...stability from childhood to older age. The 6-Day Sample (N = 1,208) were rated on six personality characteristics by their teachers at around age 14. In 2012, the authors traced as many of these participants as possible and invited them to take part in a follow-up study. Those who agreed (N = 174) completed a questionnaire booklet at age 77 years, which included rating themselves and asking someone who knew them well to rate them on the same 6 characteristics on which they were rated in adolescence. Each set of 6 ratings was reduced to the same single underlying factor, denoted dependability, a trait comparable to conscientiousness. Participants' and others' older-age personality characteristic ratings were moderately correlated with each other, and with other measures of personality and wellbeing, but correlations suggested no significant stability of any of the 6 characteristics or their underlying factor, dependability, over the 63-year interval. However, a more complex model, controlling rater effects, indicated significant 63-year stability of 1 personality characteristic, Stability of Moods, and near-significant stability of another, Conscientiousness. Results suggest that lifelong differential stability of personality is generally quite low, but that some aspects of personality in older age may relate to personality in childhood.
To understand how the emerging public health issue of chemsex relates to broader patterns of sexualised drug use (SDU) among men who have sex with men (MSM), which has been understudied.
Potential ...participants were invited to take part in an anonymous, cross-sectional online survey through Facebook advertising and community organisations' social media posts (April-June 2018). Multivariable logistic regression was used to compare MSM who engaged in recent SDU (past 12 months) with those who did not, and those who engaged in chemsex (γ-hydroxybutyrate/γ-butyrolactone, crystal methamphetamine, mephedrone, ketamine) with those who engaged in other SDU (eg, poppers, cocaine, cannabis).
Of the 1648 MSM included, 41% reported recent SDU; 15% of these (6% of total, n=99) reported chemsex. Factors associated with SDU were recent STI diagnosis (aOR=2.44, 95% CI 1.58 to 3.76), sexual health clinic attendance (aOR=2.46, 95% CI 1.90 to 3.20), image and performance-enhancing drug use (aOR=3.82, 95% CI 1.87 to 7.82), greater number of condomless anal male partners, lower satisfaction with life and greater sexual satisfaction. Predictors of chemsex compared with other SDU were not being UK-born (aOR=2.02, 95% CI 1.05 to 3.86), living in a densely populated area (aOR=2.69, 95% CI 1.26 to 5.74), low sexual self-efficacy (aOR=4.52, 95% CI 2.18 to 9.40) and greater number of condomless anal male partners. Living with HIV, taking pre-exposure prophylaxis (PrEP), and experiencing or being unsure of experiencing sexual contact without consent were significantly associated with SDU and chemsex in bivariate analyses but not in the multivariable.
Health and behavioural differences were observed between MSM engaging in chemsex, those engaging in SDU and those engaging in neither. While some MSM engaging in chemsex and SDU appeared content with these behaviours, the association with life satisfaction and sexual self-efficacy indicates psychosocial support is needed for some. The association with sexual risk and sexual consent also indicates the importance of promoting harm reduction among this population (eg, condoms, PrEP, drug knowledge).
Objectives To examine the association between intelligence measured in childhood and leading causes of death in men and women over the life course.Design Prospective cohort study based on a whole ...population of participants born in Scotland in 1936 and linked to mortality data across 68 years of follow-up.Setting Scotland.Participants 33 536 men and 32 229 women who were participants in the Scottish Mental Survey of 1947 (SMS1947) and who could be linked to cause of death data up to December 2015.Main outcome measures Cause specific mortality, including from coronary heart disease, stroke, specific cancer types, respiratory disease, digestive disease, external causes, and dementia.Results Childhood intelligence was inversely associated with all major causes of death. The age and sex adjusted hazard ratios (and 95% confidence intervals) per 1 SD (about 15 points) advantage in intelligence test score were strongest for respiratory disease (0.72, 0.70 to 0.74), coronary heart disease (0.75, 0.73 to 0.77), and stroke (0.76, 0.73 to 0.79). Other notable associations (all P<0.001) were observed for deaths from injury (0.81, 0.75 to 0.86), smoking related cancers (0.82, 0.80 to 0.84), digestive disease (0.82, 0.79 to 0.86), and dementia (0.84, 0.78 to 0.90). Weak associations were apparent for suicide (0.87, 0.74 to 1.02) and deaths from cancer not related to smoking (0.96, 0.93 to 1.00), and their confidence intervals included unity. There was a suggestion that childhood intelligence was somewhat more strongly related to coronary heart disease, smoking related cancers, respiratory disease, and dementia in women than men (P value for interactions <0.001, 0.02, <0.001, and 0.02, respectively).Childhood intelligence was related to selected cancer presentations, including lung (0.75, 0.72 to 0.77), stomach (0.77, 0.69 to 0.85), bladder (0.81, 0.71 to 0.91), oesophageal (0.85, 0.78 to 0.94), liver (0.85, 0.74 to 0.97), colorectal (0.89, 0.83 to 0.95), and haematopoietic (0.91, 0.83 to 0.98). Sensitivity analyses on a representative subsample of the cohort observed only small attenuation of the estimated effect of intelligence (by 10-26%) after adjustment for potential confounders, including three indicators of childhood socioeconomic status. In a replication sample from Scotland, in a similar birth year cohort and follow-up period, smoking and adult socioeconomic status partially attenuated (by 16-58%) the association of intelligence with outcome rates.Conclusions In a whole national population year of birth cohort followed over the life course from age 11 to age 79, higher scores on a well validated childhood intelligence test were associated with lower risk of mortality ascribed to coronary heart disease and stroke, cancers related to smoking (particularly lung and stomach), respiratory diseases, digestive diseases, injury, and dementia.
The evolution of grasses using C₄ photosynthesis and their sudden rise to ecological dominance 3 to 8 million years ago is among the most dramatic examples of biome assembly in the geological record. ...A growing body of work suggests that the patterns and drivers of C₄ grassland expansion were considerably more complex than originally assumed. Previous research has benefited substantially from dialog between geologists and ecologists, but current research must now integrate fully with phylogenetics. A synthesis of grass evolutionary biology with grassland ecosystem science will further our knowledge of the evolution of traits that promote dominance in grassland systems and will provide a new context in which to evaluate the relative importance of C₄ photosynthesis in transforming ecosystems across large regions of Earth.
Aim Many tropical savannas are undergoing a trend of increasing woody biomass, or 'woody thickening'. Management to reduce fire frequency and intensity in savannas could substantially increase the ...amount of carbon stored in woody biomass. We addressed two questions: (1) are northern Australian savannas thickening; and (2) to what extent, and by what demographic processes, does fire affect woody biomass accumulation? Location Three large national parks, covering 24,000 km 2 , in monsoonal northern Australia. Methods We examined changes in woody biomass carbon stocks – inferred from tree basal area and the density of woody understorey plants – over a 10-year period in 136 savanna monitoring plots. We statistically assessed these changes in relation to fire frequency and severity. We used a meta-analysis to identify general trends in woody cover in Australian savannas over the last half-century. Results Woody biomass carbon stocks were relatively stable across the three national parks, but rates of change were statistically indistinguishable from earlier findings of a weak thickening trend. Change was negatively correlated with fire frequency, particularly the frequency of severe fires. High frequencies of severe fires decreased rates of accumulation of biomass by existing trees (through reductions in tree growth and death of individual stems), rather than whole-tree mortality and suppression of recruitment. However, across northern Australia, our meta-analysis identified a general, albeit weak, trend of woody thickening. Main conclusions The drivers of northern Australia's weak thickening trend are uncertain, but likely candidates include increasing atmospheric CO 2 concentration and water availability, and pastoral intensification. We demonstrate that changes to fire management have the potential to either increase or decrease rates of woody thickening relative to any underlying trend. Understanding how savanna fires affect woody biomass, and how fire effects are mediated by climate and CO 2 , are essential research priorities to predict the fate of savannas.
Gallium-68 (
Ga) is a positron-emitting isotope used for clinical PET imaging of peptide receptor expression.
Ga radiopharmaceuticals used in molecular PET imaging consist of disease-targeting ...biomolecules tethered to chelators that complex
Ga
. Ideally, the chelator will rapidly, quantitatively and stably coordinate
Ga
at room temperature, near neutral pH and low chelator concentration, allowing for simple routine radiopharmaceutical formulation. Identification of chelators that fulfil these requirements will facilitate development of kit-based
Ga radiopharmaceuticals. Herein the reaction of a range of widely used macrocyclic and acyclic chelators with
Ga
is reported. Radiochemical yields have been measured under conditions of varying chelator concentrations, pH (3.5 and 6.5) and temperature (25 and 90 °C). These chelators are: 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA), 1,4,7-triazacyclononane macrocycles substituted with phosphonic (NOTP) and phosphinic (TRAP) groups at the amine, bis(2-hydroxybenzyl)ethylenediaminediacetic acid (HBED), a tris(hydroxypyridinone) containing three 1,6-dimethyl-3-hydroxypyridin-4-one groups (THP) and the hexadentate tris(hydroxamate) siderophore desferrioxamine-B (DFO). Competition studies have also been undertaken to assess relative complexation efficiencies of each chelator for
Ga
under different pH and temperature conditions. Performing radiolabelling reactions at pH 6.5, 25 °C and 5-50 μM chelator concentration resulted in near quantitative radiochemical yields for all chelators, except DOTA. Radiochemical yields either decreased or were not substantially improved when the reactions were undertaken at lower pH or at higher temperature, except in the case of DOTA. THP and DFO were the most effective
Ga
chelators at near-neutral pH and 25 °C, rapidly providing near-quantitative radiochemical yields at very low chelator concentrations. NOTP and HBED were only slightly less effective under these conditions. In competition studies with all other chelators, THP demonstrated highest reactivity for
Ga
complexation under all conditions. These data point to THP possessing ideal properties for rapid, one-step kit-based syntheses of
Ga-biomolecules for molecular PET imaging. LC-MS and
H,
C{
H} and
Ga NMR studies of HBED complexes of Ga
showed that under the analytical conditions employed in this study, multiple HBED-bound Ga complexes exist. X-ray diffraction data indicated that crystals isolated from these solutions contained octahedral Ga(HBED)(H
O), with HBED coordinated in a pentadentate N
O
mode, with only one phenolic group coordinated to Ga
, and the remaining coordination site occupied by a water molecule.
Chemsex is a specific form of sexualised drug use (SDU) that is an emerging public health issue among men who have sex with men (MSM). Although the recent focus on chemsex is a reflection of the ...associated harms it is important to understand SDU more broadly and its associations with risk behaviours. Additionally, some of the reasons suggested for MSM engagement in SDU are also likely to apply to women who have sex with women (WSW) and trans people. The aim of this review was to investigate SDU, including chemsex, among lesbian, gay, bisexual and trans (LGBT) people internationally in relation to sexual health outcomes (HIV status, STI diagnosis, condom use).
Papers that were published between January 2010 and June 2020 reporting SDU in MSM, WSW, or trans people were identified through Medline, PsycINFO, CINAHL Plus and Web of Science. Results were synthesised using a narrative approach.
The search identified 2,710 publications, of which 75 were included in the final synthesis. The majority of studies measured SDU among MSM (n = 71), and four studies measured SDU among trans people. Research into SDU had been conducted in 55 countries and 32 countries had recorded the use of a chemsex drug among MSM, although the drugs used to define chemsex varied. Among studies that researched MSM, SDU was most commonly investigated in relation to condomless anal intercourse (n = 42), followed by HIV prevalence (n = 35), and then STI diagnoses (n = 27). Drug use was generally associated with sexual health outcomes, but particularly in chemsex studies.
SDU research is lacking among WSW and trans people, despite trans women having a high HIV prevalence. Among MSM, most drugs were associated with sexual health outcomes, and therefore it is important to include both chemsex drugs and other drugs in SDU research.
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