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Recent paleoclimatic studies suggest that changes in the tropical rainbelt across the Atlantic Ocean during the past two millennia are linked to a latitudinal shift of the Intertropical Convergence Zone (ITCZ) driven by the Northern Hemisphere (NH) climate. However, little is known regarding other potential drivers that can affect tropical Atlantic rainfall, mainly due to the scarcity of adequate and high-resolution records. In this study, we fill this gap by reconstructing precipitation changes in Northeastern Brazil during the last 2,300 years from a high-resolution lake record of hydrogen isotope compositions of plant waxes. We find that regional precipitation along the coastal area of South America was not solely governed by north-south displacements of the ITCZ due to changes in NH climate, but also by the contraction and expansion of the tropical rainbelt due to variations in sea surface temperature and southeast trade winds in the tropical South Atlantic Basin.

There is a consensus that mass vaccination against SARS-CoV-2 will ultimately end the COVID-19 pandemic. However, it is not clear when and which control measures can be relaxed during the rollout of vaccination programmes. We investigate relaxation scenarios using an age-structured transmission model that has been fitted to age-specific seroprevalence data, hospital admissions, and projected vaccination coverage for Portugal. Our analyses suggest that the pressing need to restart socioeconomic activities could lead to new pandemic waves, and that substantial control efforts prove necessary throughout 2021. Using knowledge on control measures introduced in 2020, we anticipate that relaxing measures completely or to the extent as in autumn 2020 could launch a wave starting in April 2021. Additional waves could be prevented altogether if measures are relaxed as in summer 2020 or in a step-wise manner throughout 2021. We discuss at which point the control of COVID-19 would be achieved for each scenario. Despite the consensus that mass vaccination against SARS-CoV-2 will ultimately end the pandemic, it is not clear when and which control measures can be relaxed during the rollout of vaccination programmes. Here, the authors investigate relaxation scenarios using an age-structured transmission model that has been fitted to data for Portugal.

Astrocytes, a major cell type found throughout the central nervous system, have general roles in the modulation of synapse formation and synaptic transmission, blood–brain barrier formation, and regulation of blood flow, as well as metabolic support of other brain resident cells. Crucially, emerging evidence shows specific adaptations and astrocyte-encoded functions in regions, such as the spinal cord and cerebellum. To investigate the true extent of astrocyte molecular diversity across forebrain regions, we used single-cell RNA sequencing. Our analysis identifies five transcriptomically distinct astrocyte subtypes in adult mouse cortex and hippocampus. Validation of our data in situ reveals distinct spatial positioning of defined subtypes, reflecting the distribution of morphologically and physiologically distinct astrocyte populations. Our findings are evidence for specialized astrocyte subtypes between and within brain regions. The data are available through an online database ( https://holt-sc.glialab.org/ ), providing a resource on which to base explorations of local astrocyte diversity and function in the brain. Astrocytes are a major cell type in the central nervous system. Using single cell transcriptome sequencing, the authors identify multiple astrocyte subtypes in the adult mouse CNS, which map to distinct spatial locations and show correlations to cell morphology and physiology.

This study aimed to establish a protocol for in vitro embryo production using epididymal sperm (EP). Samples were obtained from ejaculated sperm (EJ) and the epididymis of 7 Gir bulls. First, the effect of heparin (+) on the viability, longevity (Experiment 1) and fertilization rates (Experiment 2) of the EP was evaluated. In experiment 2, a pool of EP and EJ sperm (n = 7) was coincubated with cumulus-oocyte complexes (COCs) for 0, 3, 6, 12 and 18 h, and the fertilization rate (FR) was evaluated. A third experiment was performed to test sperm treatments for IVP using the Percoll (P) or PureSperm (PS) gradients or a spTALP wash for sperm selection. Cleavage, blastocyst rate (BR) and embryo sex were evaluated. In experiment 4, embryos were produced using 6, 12, and 18 h of sperm-oocyte coincubation. The cleavage, BR, and total number and percentage of apoptotic cells were determined. Heparin affected EP viability, longevity and FR. After 6 h, 82% of the oocytes were fertilized in the EP+ group, a higher value (P<0.05) than that in the EJ (19%) and EP- (42%) groups. At 12 and 18 h, FR remained higher in the EP+ group, and a gradual increase in polyspermy was observed. The use of a P or PS gradient yielded a similar BR on D7 (54% and 52%), which was higher than the rate obtained using the washing method (37%). The embryos produced by EP and selected in a P or PS gradient resulted in a sex deviation in favor of male embryos (P>0.05). No differences (P>0.05) were observed among the groups that were coincubated for 6, 12 and 18 h with respect to embryo production, kinetics of development, total cell number and percentage of apoptotic cells. In conclusion, IVF time can be reduced to 6 h without affecting embryo production and quality. In addition, EP sperm selection can be performed by either a PS or P gradient.

Increasing evidence indicates that exercise has beneficial effects on chronic inflammation, cardiorespiratory function, muscle and bone strength and metabolic markers in adults with chronic kidney disease (CKD), kidney failure or kidney transplants. However, the mechanisms that underlie these benefits have received little attention, and the available clinical evidence is mainly from small, short-duration (<12 weeks) exercise intervention studies. The available data, mainly from patients with CKD or on dialysis, suggest that exercise-mediated shifts towards a less inflammatory immune cell profile, enhanced activity of the NRF2 pathway and reduced monocyte infiltration into adipose tissue may underlie improvements in inflammatory biomarkers. Exercise-mediated increases in nitric oxide release and bioavailability, reduced angiotensin II accumulation in the heart, left ventricular remodelling and reductions in myocardial fibrosis may contribute to improvements in left ventricular hypertrophy. Exercise stimulates an anabolic response in skeletal muscle in CKD, but increases in mitochondrial mass and satellite cell activation seem to be impaired in this population. Exercise-mediated activation of the canonical wnt pathway may lead to bone formation and improvements in the levels of the bone-derived hormones klotho and fibroblast growth factor 23 (FGF23). Longer duration studies with larger sample sizes are needed to confirm these mechanisms in CKD, kidney failure and kidney transplant populations and provide evidence for targeted exercise interventions.This Review discusses the potential mechanisms by which regular exercise has beneficial effects on chronic inflammation, cardiovascular health, lipid metabolism, insulin resistance, sarcopenia and bone health in people with kidney disease. The authors highlight areas for further investigation to enhance the benefits of exercise for this population.

A main challenge in deploying wireless sensor networks (WSNs) is determining the minimum quantity of sensor nodes required to fully cover the region of interest while avoiding coverage holes. This study proposes a method to compute the number of nodes needed to monitor a circular region and a distributed control strategy based on circular formations to move dynamic agents to their desired positions. The method addresses the coverage problem, ensuring that each point in the monitored region is detected without losing connectivity. In addition, the study compares this approach with a sensor node allocation method based on Voronoi diagrams, highlighting the need for an algorithm that computes the desired positions of the agents to provide guaranteed flawless coverage; the proposed method achieves this by obtaining the desired final positions. The hybrid WSN architecture, together with the proposed method, achieves full coverage efficiently and better utilizes the detection circumference of sensors compared to traditional rectangular monitoring regions.

Close-up and macro photography can reveal the natural history of small organisms in fine detail. We observed a stunning example when author YFM was photographing an adult male huntsman spider (Sparassidae) on a leaf of a piperaceous plant in the coastal Atlantic Forest of southeastern Brazil. On closer inspection of the image, he was surprised to detect a cranefly larva (probably Geranomyia sp) inside a globular, transparent clump of jelly upon the leaf. Although potentially a nutritious delicacy for the spider, the larvae remained motionless, immersed within the jelly mass and undetected by the spider as it walked across the leaf.

Body size is one of the most relevant determinants of survival. Although known to prey on vertebrates, spiders in the Theraphosidae family can also be easy prey for vertebrate predators. With its distinctive beak and large body size, this toco toucan (Ramphastos toco)--shown here in the Caiman Ecological Refuge, within the Brazilian portion of the Pantanal--does not seem to mind the chelicera (mouthparts) of the tarantula it captured, in what is, perhaps, the first record of this species interaction. Even though the tarantula is a large prey item and has defensive structures such as urticating hairs, the predatory toucan did not appear to be intimidated. For several long and harrowing minutes, the toucan manipulated the spider with its beak, and finally threw it against the tree's trunk before consuming it.

Chronic kidney disease (CKD) is a prevalent worldwide public burden that increasingly compromises overall health as the disease progresses. Two of the most negatively affected tissues are bone and skeletal muscle, with CKD negatively impacting their structure, function and activity, impairing the quality of life of these patients and contributing to morbidity and mortality. Whereas skeletal health in this population has conventionally been associated with bone and mineral disorders, sarcopenia has been observed to impact skeletal muscle health in CKD. Indeed, bone and muscle tissues are linked anatomically and physiologically, and together regulate functional and metabolic mechanisms. With the initial crosstalk between the skeleton and muscle proposed to explain bone formation through muscle contraction, it is now understood that this communication occurs through the interaction of myokines and osteokines, with the skeletal muscle secretome playing a pivotal role in the regulation of bone activity. Regular exercise has been reported to be beneficial to overall health. Also, the positive regulatory effect that exercise has been proposed to have on bone and muscle anatomical, functional, and metabolic activity has led to the proposal of regular physical exercise as a therapeutic strategy for muscle and bone-related disorders. The detection of bone- and muscle-derived cytokine secretion following physical exercise has strengthened the idea of a cross communication between these organs. Hence, this review presents an overview of the impact of CKD in bone and skeletal muscle, and narrates how these tissues intrinsically communicate with each other, with focus on the potential effect of exercise in the modulation of this intercommunication.

Knowledge about genetic diversity is essential to promote effective use and conservation of crops, because it enables farmers to adapt their crops to specific needs and is the raw material for breeding. Manioc ( Manihot esculenta ssp. esculenta ) is one of the world’s major food crops and has the potential to help achieve food security in the context of on-going climate changes. We evaluated single nucleotide polymorphisms in traditional Brazilian manioc varieties conserved in the gene bank of the Luiz de Queiroz College of Agriculture, University of São Paulo. We assessed genome-wide diversity and identified selective signatures contrasting varieties from different biomes with samples of manioc’s wild ancestor M . esculenta ssp. flabellifolia . We identified signatures of selection putatively associated with resistance genes, plant development and response to abiotic stresses that might have been important for the crop’s domestication and diversification resulting from cultivation in different environments. Additionally, high neutral genetic diversity within groups of varieties from different biomes and low genetic divergence among biomes reflect the complexity of manioc’s evolutionary dynamics under traditional cultivation. Our results exemplify how smallholder practices contribute to conserve manioc’s genetic resources, maintaining variation of potential adaptive significance and high levels of neutral genetic diversity.