Neural signature of fictive learning signals in a sequential investment task

Reinforcement learning models now provide principled guides for a wide range of reward learning experiments in animals and humans. One key learning (error) signal in these models is experiential and reports ongoing temporal differences between expected and experienced reward. However, these same abstract learning models also accommodate the existence of another class of learning signal that takes the form of a fictive error encoding ongoing differences between experienced returns and returns that "could-have-been-experienced" if decisions had been different. These observations suggest the hypothesis that, for all real-world learning tasks, one should expect the presence of both experiential and fictive learning signals. Motivated by this possibility, we used a sequential investment game and fMRI to probe ongoing brain responses to both experiential and fictive learning signals generated throughout the game. Using a large cohort of subjects (n = 54), we report that fictive learning signals strongly predict changes in subjects' investment behavior and correlate with fMRI signals measured in dopaminoceptive structures known to be involved in valuation and choice

Agroforestry and Smallholder Farmers: Climate Change Adaptation through Sustainable Land Use

Agriculture in the developing world will be extremely hard hit by climate change, and smallholder farmers in Least Developed Countries (LDCs) are among the most vulnerable to its impacts. There is a range of agricultural adaptations to climate change, and each context demands a unique appraisal of impacts and adaptations based on specific geography, local climate variability and expected change, and social conditions. The term “climate-smart agriculture” (CSA) has come to embody a set of practices in crop and livestock cultivation that 1) reduce greenhouse gas emissions (climate change mitigation), 2) build resilience to the impacts of climate change for farmers (climate change adaptation), and 3) boost agricultural productivity and farmer incomes (advancing food security). Agroforestry, a form of CSA, is a promising adaptation option for smallholder farmers throughout the developing world. The diverse adaptive benefits of agroforestry have been captured in case examples and scientific studies in developing countries in Asia, Africa, and Central and South America. This paper examines the emphasis on climate change mitigation through agriculture, pointing out that this is only a small additional benefit of climate-smart practices; the climate crisis will not be solved without far broader mitigation efforts targeting fossil fuel combustion. Further, focusing conversations about agriculture on climate change mitigation can take necessary attention away from the critical need to build resilience for the developing world’s vulnerable smallholder farmers via agroforestry and other types of CSA. Based on the benefits it provides, agroforestry offers an emerging opportunity for local, community-level adaptation to climate change. The “re-greening” movement in Africa’s Sahel region illustrates this point. Further, agroforestry promotes sustainable natural resource management and builds upon existing knowledge. Traditional knowledge needs to be actively sought out, thoroughly assessed, and acted upon. Successful adaptation policies via agroforestry bring together traditional knowledge of agroecological systems with modern scientific analysis and understanding of agroforestry’s potential in individual geographical settings. Finally, agroforestry is a case study in the potential for a balanced relationship between human beings and their natural surroundings; this principle will be critical to addressing the climate crisis in the long-term, and seeking a sustainable arrangement for the future of human life on earth

Following Lives Undergoing Change (Flux) study: Implementation and baseline prevalence of drug use in an online cohort study of gay and bisexual men in Australia

Background: Drug use among gay and bisexual men (GBM) is higher than most populations. The use of crystal methamphetamine, erectile dysfunction medication (EDM), and amyl nitrite have been associated with sexual risk behaviour and HIV infection among gay and bisexual men (GBM). Objective: This paper describes an online prospective observational study of licit and illicit drug use among GBM and explores baseline prevalence of drug use in this sample. Capturing these data poses challenges as participants are required to disclose potentially illegal behaviours in a geographically dispersed country. To address this issue, an entirely online and study specific methodology was chosen. Methods: Men living in Australia, aged 16.5 years of age or older, who identified as homosexual or bisexual or had sex with at least one man in the preceding 12 months were eligible to enrol. Results: Between September 2014 and July 2015, a total of 2250 participants completed the baseline questionnaire, of whom, 1710 (76.0%) consented to six-monthly follow-up. The majority (65.7%) were recruited through Facebook targeted advertising. At baseline, over half (50.5%) the men reported the use of any illicit drug in the previous six months, and 28.0% had used party drugs. In the six months prior to enrolment, 12.0% had used crystal methamphetamine, 21.8% had used EDM, and 32.1% had used amyl nitrite. Among the 1710 men enrolled into the cohort, 790 men had used none of these drugs. Conclusion: Ease of entry and minimal research burden on participants helped ensure successful recruitment into this online cohort study. Study outcomes will include the initiation and cessation of drug use, associated risk behaviours, and health consequences, over time. Results will provide insights into the role gay community plays in patterns of drug use among GBM

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

Effect modification and interaction between ethnicity and socioeconomic factors in severe COVID-19 : analyses of linked national data for Scotland

This work was supported by the Economic and Social Research Council (grant number ES/W000849/1) and the Medical Research Council (MC_PC_19075). The funders had no role in the study design, data collection and analysis, decision to publish or preparation of the manuscript. RM, SA, EK, ED, AHL, AP and SVK are supported by the Medical Research Council (MC_UU_00022/2) and the Scottish Government Chief Scientist Office (SPHSU17). SVK acknowledges funding from an NRS Senior Clinical Fellowship (SCAF/15/02), the Medical Research Council (MC_UU_00022/2) and the Scottish Government Chief Scientist Office (SPHSU17). AP acknowledges funding from Wellcome Trust (205412/Z/16/Z).Objective Minority ethnic groups disproportionately experienced adverse COVID-19 outcomes, partly a consequence of disproportionate exposure to socioeconomic disadvantage and high-risk occupations. We examined whether minority ethnic groups were also disproportionately vulnerable to the consequences of socioeconomic disadvantage and high-risk occupations in Scotland. Design We investigated effect modification and interaction between area deprivation, education and occupational risk and ethnicity (assessed as both a binary white vs non-white variable and a multi-category variable) in relation to severe COVID-19 (hospitalisation or death). We used electronic health records linked to the 2011 census and Cox proportional hazards models, adjusting for age, sex and health board. We were principally concerned with additive interactions as a measure of vulnerability, estimated as the relative excess risk due to interaction (RERI). Results Analyses considered 3 730 837 individuals aged ≥16 years (with narrower age ranges for analyses focused on education and occupation). Severe COVID-19 risk was typically higher for minority ethnic groups and disadvantaged socioeconomic groups, but additive interactions were not consistent. For example, non-white ethnicity and highest deprivation level experienced elevated risk ((HR=2.7, 95% CI: 2.4, 3.2) compared with the white least deprived group. Additive interaction was not present (RERI=−0.1, 95% CI: −0.4, 0.2), this risk being less than the sum of risks of white ethnicity/highest deprivation level (HR=2.4, 95% CI: 2.3, 2.5) and non-white ethnicity/lowest deprivation level (1.4, 95% CI: 1.2, 1.7). Similarly, non-white ethnicity/no degree education (HR=2.5, 95% CI: 2.2, 2.7; RERI=−0.1, 95% CI: −0.4, 0.2) and non-white ethnicity/high-risk occupation (RERI=0.3, 95% CI: −0.2, 0.8) did not experience greater than additive risk. No clear evidence of effect modification was identified when using the multicategory ethnicity variable or on the multiplicative scale either. Conclusion We found no definitive evidence that minority ethnic groups were more vulnerable to the effect of social disadvantage on the risk of severe COVID-19.Peer reviewe

Can understanding reward help illuminate anhedonia?

Purpose of review: The goal of this paper is to examine how reward processing might help us understand the symptom of anhedonia. Recent findings: There are extensive reviews exploring the relationship between responses to rewarding stimuli and depression. These often include a discussion on anhedonia and how this might be underpinned in particular by dysfunctional reward processing. However, there is no specific consensus on whether studies to date have adequately examined the various sub-components of reward processing or how these might relate in turn to various aspects of anhedonia symptoms. Summary: The approach to understanding the symptom of anhedonia should be to examine all the sub-components of reward processing at the subjective and objective behavioural and neural level, with well validated tasks that can be replicated. Investigating real life experiences of anhedonia and how theses might be predicted by objective lab measures is also needed in future research

Investigating the contribution of socioeconomic position to ethnic inequalities in severe COVID-19 outcomes : population-based mediation analyses of national linked Scottish data

Funding: This work was supported by the ESRC (grant number ES/W000849/1). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. SA, EK, RM, ED, AHL, KH, AP and SVK are supported by Medical Research Council (MC_UU_00022/2) and the Scottish Government Chief Scientist Office (SPHSU17). SVK acknowledges funding from a NRS Senior Clinical Fellowship (SCAF/15/02). AP acknowledges funding from Wellcome Trust (205412/Z/16/Z).We quantified the extent to which socio-economic position (SEP) contributed to ethnic inequalities in severe COVID-19 outcomes (hospitalization or death) in Scotland. We used linked 2011 Scottish Census and health records to assess whether ethnic inequalities were mediated by different SEP measures: area deprivation, educational status, household composition, and multigenerational household. We considered disaggregated ethnicities ‘White Scottish’, ‘White British or Irish’, ‘Other White’, ‘South Asian’, ‘African, Caribbean, or Black’, and ‘Other’. We applied marginal structural models to estimate causal pathways. Of the 3 297 205 individuals analysed, 38 213 (1.2%) had severe COVID-19 outcomes. South Asians had elevated risk of severe COVID-19 compared to White Scottish (hazard ratio: 1.7; 95% confidence interval: 1.5–1.9), while White British or Irish (hazard ratio: 0.7; confidence interval: 0.6–08) and other White (hazard ratio: 0.8; confidence interval: 0.7–0.9) had reduced risk. When holding area deprivation constant, the risk of severe COVID-19 declined by 16.5% for South Asians and 49.2% for White British or Irish; but increased for other White (75.4%). When holding education constant, the risk of severe COVID-19 reduced by 24.8% for White British or Irish and 20.6% for other White; but increased by 74.6% for South Asians. Only a slight change in risk was observed for the South Asians after holding household size and multigenerational household constant. Risk estimates for African, Caribbean or Black, and other groups were underpowered. SEP measures differed substantially in the extent to which they mediated ethnic inequalities in severe COVID-19. This highlights the necessity of addressing multiple dimensions of SEP that drive ethnic inequalities.Peer reviewe

Are ethnic inequalities in COVID-19 outcomes mediated by occupation risk?:Analyses of a 2-year record linked national cohort study in Scotland

This study investigated the extent to which ethnic inequalities in severe COVID-19 (i.e. hospitalization or deaths) are mediated through occupational risk differences. We used a population-based cohort study linking the 2011 Scottish Census to health records. We included all individuals aged 30-64 years and living in Scotland on 1 March 2020. The study period was from 1 March 2020 to 17 April 2022. Self-reported ethnicity was taken from the Census. We derived occupational risk of SARS-COV-2 infection using the 3-digit Standard Occupational Classification (SOC2010). We estimated hazard ratios (HRs) of total effects and controlled direct effects of ethnicity on severe COVID-19 mediated by occupational risk using marginal structural Cox models and subsequent proportional change. For aggregated ethnic groups, Non-White groups experienced a higher risk of severe COVID-19 (HR 1.6; 95% CI 1.4-1.8) compared to White group (all White ethnic groups) which increased to (1.7; 1.4-2.1) after accounting for occupational risk, representing a 6.0% change. For disaggregated ethnic groups, risks for South Asian (2.0; 1.8-2.3), African, Caribbean, or Black (1.3; 0.9-1.7) and Other ethnic groups (1.1; 0.9-1.3) were higher compared to White Scottish. After accounting for occupational risk, estimated risk of severe COVID-19 remained elevated for South Asian (1.8; 1.2-2.3), African Caribbean or Black (1.4; 0.8-2.1) and Other ethnic group (1.7; 1.1-2.3) representing a reduction of 11.8% and increases of 16.4% and 59.0%, respectively. Our findings suggest that ethnic inequalities in severe COVID-19 were impacted by differences in occupational risk.</p

Report on the sixth blind test of organic crystal-structure prediction methods

The sixth blind test of organic crystal-structure prediction (CSP) methods has been held, with five target systems: a small nearly rigid molecule, a polymorphic former drug candidate, a chloride salt hydrate, a co-crystal, and a bulky flexible molecule. This blind test has seen substantial growth in the number of submissions, with the broad range of prediction methods giving a unique insight into the state of the art in the field. Significant progress has been seen in treating flexible molecules, usage of hierarchical approaches to ranking structures, the application of density-functional approximations, and the establishment of new workflows and "best practices" for performing CSP calculations. All of the targets, apart from a single potentially disordered Z` = 2 polymorph of the drug candidate, were predicted by at least one submission. Despite many remaining challenges, it is clear that CSP methods are becoming more applicable to a wider range of real systems, including salts, hydrates and larger flexible molecules. The results also highlight the potential for CSP calculations to complement and augment experimental studies of organic solid forms