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IntroductionSince the WHO declared COVID-19 as a pandemic, the spread of the new coronavirus has been the focus of attention of scientists, governments and populations. One of the main concerns is the impact of this pandemic on health outcomes, mainly on mental health. Even though there are a few empirical studies on COVID-19 and mental health, so far, there is no systematic review about the impact of COVID-19 on mental health of young people and adults yet. We aim to critically synthesise the scientific evidence about the impact of the COVID-19 pandemic on the mental health of young people and adults.Methods and analysisA systematic review will be performed through eight databases: MEDLINE (Medical Literature Analysis and Retrieval System Online), ISI-of-Knowledge, CENTRAL (Cochrane Central Register of Controlled Trials), EMBASE (Excerpta Medica Database), SCOPUS, LILACS (Latin American and Caribbean Health Sciences Literature), PsycINFO (Psychology Information) and CNKI (Chinese National Knowledge Infrastructure), from inception until 30 June 2020. No restriction regarding the publication date, setting or languages will be considered. Preliminary search strategies were carried out on 29 March 2020 and will be updated in June 2020. The primary outcomes will be the prevalence and the severity of psychological symptoms in young people and adults (>18 years old) resulting from the impact of COVID-19 pandemic. Study selection will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Pooled standardised mean differences and 95% CIs will be calculated. The risk of bias of the observational studies will be assessed through the Methodological Index for Non-Randomised Studies (MINORS). Additionally, if sufficient data are available, a meta-analysis will be conducted. Heterogeneity between the studies will be determined by the I2 statistics. Subgroup analyses will also be performed. Publication bias will be checked with funnel plots and Egger’s test. Heterogeneity will be explored by random-effects analysis.Ethics and disseminationEthical assessment was not required. Findings will be disseminated through peer-reviewed publication and will be presented at conferences related to this field.PROSPERO registration numberCRD42020177366.

We show an annual overview of the sea-air CO 2 exchanges and primary drivers in the Gerlache Strait, a hotspot for climate change that is ecologically important in the northern Antarctic Peninsula. In autumn and winter, episodic upwelling events increase the remineralized carbon in the sea surface, leading the region to act as a moderate or strong CO 2 source to the atmosphere of up to 40 mmol m –2  day –1 . During summer and late spring, photosynthesis decreases the CO 2 partial pressure in the surface seawater, enhancing ocean CO 2 uptake, which reaches values higher than − 40 mmol m –2  day –1 . Thus, autumn/winter CO 2 outgassing is nearly balanced by an only 4-month period of intense ocean CO 2 ingassing during summer/spring. Hence, the estimated annual net sea-air CO 2 flux from 2002 to 2017 was 1.24 ± 4.33 mmol m –2  day –1 , opposing the common CO 2 sink behaviour observed in other coastal regions around Antarctica. The main drivers of changes in the surface CO 2 system in this region were total dissolved inorganic carbon and total alkalinity, revealing dominant influences of both physical and biological processes. These findings demonstrate the importance of Antarctica coastal zones as summer carbon sinks and emphasize the need to better understand local/regional seasonal sensitivity to the net CO 2 flux effect on the Southern Ocean carbon cycle, especially considering the impacts caused by climate change.

Age-related differences in bimanual motor performance have been extensively documented, but their underlying neural mechanisms remain less clear. Studies applying diffusion MRI in the aging population have revealed evidence for age-related white matter variations in the corpus callosum (CC) which are related to bimanual motor performance. However, the diffusion tensor model used in those studies is confounded by partial volume effects in voxels with complex fiber geometries which are present in up to 90% of white matter voxels, including the bilateral projections of the CC. A recently developed whole-brain analysis framework, known as fixel-based analysis (FBA), enables comprehensive statistical analyses of white matter quantitative measures in the presence of such complex fiber geometries. To investigate the contribution of age-related fiber-specific white matter variations to age-related differences in bimanual performance, a cross-sectional lifespan sample of healthy human adults (N ​= ​95; 20–75 years of age) performed a bimanual tracking task. Furthermore, diffusion MRI data were acquired and the FBA metrics associated with fiber density, cross-section, and combined fiber density and cross-section were estimated. Whole-brain FBA revealed significant negative associations between age and fiber density, cross-section, and combined metrics of multiple white matter tracts, including the bilateral projections of the CC, indicative of white matter micro- and macrostructural degradation with age. More importantly, mediation analyses demonstrated that age-related variations in the combined (fiber density and cross-section) metric of the genu, but not splenium, of the CC contributed to the observed age-related differences in bimanual coordination performance. These findings highlight the contribution of variations in interhemispheric communication between prefrontal (non-motor) cortices to age-related differences in motor performance. •Negative age-motor performance association amplifies with higher task complexity.•Aging is negatively associated with fiber density and cross-section.•Age-related variations in anterior interhemispheric tract mediate motor behavior.

This paper elucidates the inseparable connection between the pursuit of a more ecologically sustainable society and the quest for socioeconomic justice. It also demonstrates why Unconditional Basic Income (UBI) is an effective policy to act on both fronts. First, the corresponding theory on environmental and socioeconomic oppression sheds light on the argument that both types of domination stem from the same historical process and are inherently interconnected. Addressing one without considering the other is essentially flawed; they are both features and consequences of present society. Acknowledging the historical debt owed to vulnerable economic classes and developing countries is imperative. Green republicanism could potentially establish a theoretical foundation for social-ecological thinking. Defining freedom as non-domination and applying this concept to nature are essential prerequisites for overcoming socioeconomic and environmental oppression. UBI is presented and discussed theoretically as a strong solution to address these two challenges. It serves not only as a means to facilitate the transition to a post-productivist society, transforming labor relations, but also as a catalyst for the development of circular economies and more sustainable occupations. Additionally, the basic income policy implemented in the city of Maricá, Brazil, is cited as empirical evidence showcasing the environmental and socioeconomic values of UBI.

In the present study we examined the effect of bihemispheric in-phase synchronization of motor cortical rhythms on complex bimanual coordination. Twenty young healthy volunteers received 10 Hz or 20 Hz tACS in a double-blind crossover design while performing a bimanual task-set switching paradigm. We used a bilateral high-density montage centred over the hand knob representation within the primary motor cortices to apply tACS time-locked to the switching events. Online tACS in either frequency led to faster but more erroneous switching transitions compared to trials without active stimulation. When comparing stimulation frequencies, 10 Hz stimulation resulted in higher error rates and slower switching transitions than 20 Hz stimulation. Furthermore, the stimulation frequencies showed distinct carry-over effects in trials following stimulation trains. Non-stimulated switching transitions were generally faster but continuous performance became more erroneous over time in the 20 Hz condition. We suggest that the behavioural effects of bifocal in-phase tACS are explained by online synchronization of long-range interhemispheric sensorimotor oscillations, which impacts on interhemispheric information flow and the top-down control required for flexible control of complex bimanual actions. Different stimulation frequencies may lead to distinct offline effects, which potentially accumulate over time and therefore need to be taken into account when evaluating subsequent performance.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

There has been an increasing global demand for more sustainable production systems, especially in what concerns goods produced from natural tropical forests. The lumber industry in the Brazilian Amazon region produces a significant volume of lumber, and as a consequence of frequent non-optimal procedures, considerable amounts of waste are generated. In order to optimize the timber production and to minimize the environmental damage associated with low yields of sawmills, two features are indispensable: the lumber yield and the quality of the logs. The aim of this research was to analyze the wood quality and lumber yield of logs of tree species harvested from natural stands in the Amazon rainforest. A total of 120 logs from 21 tree species were harvested from natural stands in the state of Pará, Brazil, and analyzed for wood quality. Out of these, 60 logs were evaluated for lumber yield. The most common defects found in the logs were flattening, surface cracks, and eccentricity of the pith. By means of the principal component analysis, the Mezilaurus itauba , Protium decandrum , and Caryocar villosum species stood out. The average lumber yield was 45%. The Bowdichia nitida and C. villosum species presented the highest yield values (average of 63%). There was a trend of correlation between the lumber yield and the quality of the logs. Based on the methodology used to analyze the quality of the logs, inferences can be made on the yield of the logging and, consequently, the sustainability of the timber industries in the Brazilian Amazon.

Cigarette smoke is a complex chemical mixture, involving health-damaging components such as carbon monoxide, ammonia, pyridine, toluene and nicotine. While cognitive functions have been well documented in heavy smokers, spatial vision has been less characterized. In the article, we investigated smoking effects through contrast sensitivity function (CSF), a rigorous procedure that measures the spatial vision. Data were recorded from 48 participants, a group of non-smokers (n = 16), a group of chronic and heavy cigarette smokers (n = 16) and deprived smokers (n = 16); age range 20–45 years. Sinewave gratings with spatial frequencies ranging from 0.25 to 20 cycles per degree were used. All subjects were free from any neurological disorder, identifiable ocular disease and had normal acuity. No abnormalities were detected in the fundoscopic examination and in the optical coherence tomography exam. Contrary to expectations, performance on CSF differed between groups. Both smokers and deprived smokers presented a loss of contrast sensitivity compared to non-smokers. Post-hoc analyses suggest that deprived smokers were less sensitive at all spatial frequencies. These results suggest that not only chronic exposure to cigarette compounds but also withdrawal from nicotine affected spatial vision. This highlights the importance of understanding diffuse effects of smoking compounds on visual spatial processing.

The Southern Ocean plays a critical role in regulating global climate as a major sink for atmospheric carbon dioxide (CO2), and in global ocean biogeochemistry by supplying nutrients to the global thermocline, thereby influencing global primary production and carbon export. Biogeochemical processes within the Southern Ocean regulate regional primary production and biological carbon uptake, primarily through iron supply, and support ecosystem functioning over a range of spatial and temporal scales. Here we assimilate existing knowledge and present new data to examine the biogeochemical cycles of iron, carbon and major nutrients, their key drivers and their responses to, and roles in, contemporary climate and environmental change. Projected increases in iron supply, coupled with increases in light availability to phytoplankton through increased near-surface stratification and longer ice-free periods, are very likely to increase primary production and carbon export around Antarctica. Biological carbon uptake is likely to increase for the Southern Ocean as a whole, whilst there is greater uncertainty around projections of primary production in the Sub-Antarctic and basin-wide changes in phytoplankton species composition, as well as their biogeochemical consequences. Phytoplankton, zooplankton, higher trophic level organisms and microbial communities are strongly influenced by Southern Ocean biogeochemistry, in particular through nutrient supply and ocean acidification. In turn, these organisms exert important controls on biogeochemistry through carbon storage and export, nutrient recycling and redistribution, and benthic-pelagic coupling. The key processes described in this paper are summarised in the graphical abstract. Climate-mediated changes in Southern Ocean biogeochemistry over the coming decades are very likely to impact primary production, sea-air CO2 exchange and ecosystem functioning within and beyond this vast and critically important ocean region.

Although some studies have reported perceptual changes in psychosis, no definitive conclusions have been drawn about visual disturbances that are related to bipolar disorder (BPD). The purpose of the present study was to evaluate colour vision in BPD patients. Data were recorded from 24 participants: healthy control group ( n  = 12) and type 1 BPD group ( n  = 12). The participants were 20–45 years old and they were free from neurological disorders and identifiable ocular disease and had normal or corrected-to-normal visual acuity. Colour discrimination was evaluated using the Lanthony D-15d, Trivector and Ellipse tests, using a psychophysical forced-choice method. The relationship of visual measures to mood state and cognitive function was also investigated. The results showed that BPD patients had higher colour discrimination thresholds in the D15d ( p  < 0.001), Trivector ( p  < 0.001) and Ellipse ( p  < 0.01) tests compared with healthy controls. Linear regression analysis showed that mood state was related to colour discrimination. BPD individuals were not impaired in cognitive tasks. The present study provided new evidence of potential links between type 1 BPD and visual processing impairments. This research suggests a new direction for studies and the need for research in this field of study.