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Planetary Instrument for X-ray Lithochemistry (PIXL) is a micro-focus X-ray fluorescence spectrometer mounted on the robotic arm of NASA’s Perseverance rover. PIXL will acquire high spatial resolution observations of rock and soil chemistry, rapidly analyzing the elemental chemistry of a target surface. In 10 seconds, PIXL can use its powerful 120 μm-diameter X-ray beam to analyze a single, sand-sized grain with enough sensitivity to detect major and minor rock-forming elements, as well as many trace elements. Over a period of several hours, PIXL can autonomously raster-scan an area of the rock surface and acquire a hyperspectral map comprised of several thousand individual measured points. When correlated to a visual image acquired by PIXL’s camera, these maps reveal the distribution and abundance variations of chemical elements making up the rock, tied accurately to the physical texture and structure of the rock, at a scale comparable to a 10X magnifying geological hand lens. The many thousands of spectra in these postage stamp-sized elemental maps may be analyzed individually or summed together to create a bulk rock analysis, or subsets of spectra may be summed, quantified, analyzed, and compared using PIXLISE data analysis software. This hand lens-scale view of the petrology and geochemistry of materials at the Perseverance landing site will provide a valuable link between the larger, centimeter- to meter-scale observations by Mastcam-Z, RIMFAX and Supercam, and the much smaller (micron-scale) measurements that would be made on returned samples in terrestrial laboratories.

We have developed an optical stimulator system for vision-based sensors. The stimulator is an efficient tool for stimulating a camera during on-ground testing with scenes representative of spacecraft flights. Such scenes include starry sky, planetary objects, and other spacecraft. The optical stimulator is used as a test bench to simulate high-precision navigation by different types of camera systems that are used onboard spacecraft, planetary rovers, and for spacecraft rendezvous and proximity maneuvers. Careful hardware design and preoperational calibration of the stimulator result in high precision and long-term stability. The system can be continuously used over several days. By facilitating a full camera including optics in the loop, the stimulator enables the more realistic simulation of flight maneuvers based on navigation cameras than pure computer simulations or camera stimulations without the involvement of the actual optics.

A Correction to this paper has been published: https://doi.org/10.1007/s11214-021-00801-2

The Planetary Instrument for X-ray Lithochemistry (PIXL) is a micro-focus X-ray fluorescence spectrometer mounted on the robotic arm of NASA's Perseverance rover. PIXL will acquire high spatial resolution observations of rock and soil chemistry, rapidly analyzing the elemental chemistry of a target surface. In 10 seconds, PIXL can use its powerful 120 micrometer diameter X-ray beam to analyze a single, sand-sized grain with enough sensitivity to detect major and minor rock-forming elements, as well as many trace elements. Over a period of several hours, PIXL can autonomously scan an area of the rock surface and acquire a hyperspectral map comprised of several thousand individual measured points.

There is mounting evidence that seemingly diverse psychiatric disorders share genetic etiology, but the biological substrates mediating this overlap are not well characterized. Here we leverage the unique Integrative Psychiatric Research Consortium (iPSYCH) study, a nationally representative cohort ascertained through clinical psychiatric diagnoses indicated in Danish national health registers. We confirm previous reports of individual and cross-disorder single-nucleotide polymorphism heritability for major psychiatric disorders and perform a cross-disorder genome-wide association study. We identify four novel genome-wide significant loci encompassing variants predicted to regulate genes expressed in radial glia and interneurons in the developing neocortex during mid-gestation. This epoch is supported by partitioning cross-disorder single-nucleotide polymorphism heritability, which is enriched at regulatory chromatin active during fetal neurodevelopment. These findings suggest that dysregulation of genes that direct neurodevelopment by common genetic variants may result in general liability for many later psychiatric outcomes.Schork et al. identify novel variants contributing to shared risk among psychiatric disorders and suggest that these variants act through the disruption of early neurodevelopment.

The sleep-wake cycle regulates interstitial fluid (ISF) and cerebrospinal fluid (CSF) levels of β-amyloid (Aβ) that accumulates in Alzheimer’s disease (AD). Furthermore, chronic sleep deprivation (SD) increases Aβ plaques. However, tau, not Aβ, accumulation appears to drive AD neurodegeneration. We tested whether ISF/CSF tau and tau seeding and spreading were influenced by the sleep-wake cycle and SD. Mouse ISF tau was increased ~90% during normal wakefulness versus sleep and ~100% during SD. Human CSF tau also increased more than 50% during SD. In a tau seeding-and-spreading model, chronic SD increased tau pathology spreading. Chemogenetically driven wakefulness in mice also significantly increased both ISF Aβ and tau. Thus, the sleep-wake cycle regulates ISF tau, and SD increases ISF and CSF tau as well as tau pathology spreading.

During the Last Glacial Maximum, continental ice sheets isolated Beringia (northeast Siberia and northwest North America) from unglaciated North America. By around 15 to 14 thousand calibrated radiocarbon years before present (cal. kyr bp ), glacial retreat opened an approximately 1,500-km-long corridor between the ice sheets. It remains unclear when plants and animals colonized this corridor and it became biologically viable for human migration. We obtained radiocarbon dates, pollen, macrofossils and metagenomic DNA from lake sediment cores in a bottleneck portion of the corridor. We find evidence of steppe vegetation, bison and mammoth by approximately 12.6 cal. kyr bp , followed by open forest, with evidence of moose and elk at about 11.5 cal. kyr bp , and boreal forest approximately 10 cal. kyr bp . Our findings reveal that the first Americans, whether Clovis or earlier groups in unglaciated North America before 12.6 cal. kyr bp , are unlikely to have travelled by this route into the Americas. However, later groups may have used this north–south passageway. During much of the last ice age, continental ice sheets prevented humans from migrating into North America from Siberia; an environmental reconstruction of the corridor that opened up between the Cordilleran and Laurentide ice sheets reveals that it would have been inhospitable to the initial colonizing humans, who therefore probably entered North America by a different route. A coastal migration route to the Americas During much of the last ice age, continental ice sheets prevented humans from migrating into North America from Beringia, the area between Siberia and what is now the Bering Strait. At some point, a route opened up between the Cordilleran and Laurentide ice sheets, but it is thought that this 1,500-kilometre-long ice-free corridor may have been too cold to act as a human migration route. Eske Willerslev and colleagues present a series of environmental reconstructions based on coring of lake sediments in what was once the ice-free corridor. Their data indicate that the corridor would have still been inhospitable even after humans are known to have arrived in the Americas south of the ice. This implies that humans migrated by a coastal route, now submerged by the risen sea.

Lung cancer screening with low-dose CT can save lives. This European Union (EU) position statement presents the available evidence and the major issues that need to be addressed to ensure the successful implementation of low-dose CT lung cancer screening in Europe. This statement identified specific actions required by the European lung cancer screening community to adopt before the implementation of low-dose CT lung cancer screening. This position statement recommends the following actions: a risk stratification approach should be used for future lung cancer low-dose CT programmes; that individuals who enter screening programmes should be provided with information on the benefits and harms of screening, and smoking cessation should be offered to all current smokers; that management of detected solid nodules should use semi-automatically measured volume and volume-doubling time; that national quality assurance boards should be set up to oversee technical standards; that a lung nodule management pathway should be established and incorporated into clinical practice with a tailored screening approach; that non-calcified baseline lung nodules greater than 300 mm3, and new lung nodules greater than 200 mm3, should be managed in multidisciplinary teams according to this EU position statement recommendations to ensure that patients receive the most appropriate treatment; and planning for implementation of low-dose CT screening should start throughout Europe as soon as possible. European countries need to set a timeline for implementing lung cancer screening.

Natural amylin is a pancreatic hormone that induces satiety. Cagrilintide is a long-acting amylin analogue under investigation for weight management. We assessed the dose–response relationship of cagrilintide regarding the effects on bodyweight, safety, and tolerability. We conducted a multicentre, randomised, double-blind, placebo-controlled and active-controlled, dose-finding phase 2 trial at 57 sites including hospitals, specialist clinics, and primary care centres in ten countries (Canada, Denmark, Finland, Ireland, Japan, Poland, Serbia, South Africa, the UK, and the USA). Eligible participants were adults aged at least 18 years without diabetes, with a body-mass index of at least 30 kg/m2 or at least 27 kg/m2 with hypertension or dyslipidaemia. Participants were randomly assigned (6:1) to subcutaneous self-injections of once-weekly cagrilintide (0·3, 0·6, 1·2, 2·4, or 4·5 mg), once-daily liraglutide 3·0 mg, or volume-matched placebo (for six placebo groups). The trial had a 26-week treatment period, including a dose-escalation period of up to 6 weeks, and a 6-week follow-up period without treatment. Participants and investigators were masked to the assigned study treatment with respect to active versus pooled placebo treatment, but not to different active treatments. The primary endpoint was the percentage change in bodyweight from baseline to week 26, assessed in all randomly assigned participants according to the trial product estimand (assuming all participants were adherent to treatment) and to the treatment policy estimand (regardless of adherence to treatment). Safety was assessed in all participants who received at least one dose of randomised treatment. This trial is registered with ClinicalTrials.gov, NCT03856047, and is closed to new participants. Between March 1 and Aug 19, 2019, we randomly assigned 706 participants to cagrilintide 0·3–4·5 mg (100–102 per dose group), 99 to liraglutide 3·0 mg, and 101 to placebo. Permanent treatment discontinuation (n=73 [10%]) occurred similarly across treatment groups, mostly due to adverse events (n=30 [4%]). In total, 29 participants (4%) withdrew from the trial. According to the trial product estimand, mean percentage weight reductions from baseline were greater with all doses of cagrilintide (0·3–4·5 mg, 6·0%–10·8% [6·4–11·5 kg]) versus placebo (3·0% [3·3 kg]; estimated treatment difference range 3·0%–7·8%; p<0·001). Weight reductions were also greater with cagrilintide 4·5 mg versus liraglutide 3·0 mg (10·8% [11·5 kg] vs 9·0% [9·6 kg]; estimated treatment difference 1·8%, p=0·03). Similar weight loss reductions were observed with the treatment policy estimand. The most frequent adverse events were gastrointestinal disorders (eg, nausea, constipation, and diarrhoea) and administration-site reactions. More participants receiving cagrilintide 0·3–4·5 mg had gastrointestinal adverse events compared with placebo (41%–63% vs 32%), primarily nausea (20%–47% vs 18%). Treatment with cagrilintide in people with overweight and obesity led to significant reductions in bodyweight and was well tolerated. The findings support the development of molecules with novel mechanisms of action for weight management. Novo Nordisk A/S.

Political polarization impeded public support for policies to reduce the spread of COVID-19, much as polarization hinders responses to other contemporary challenges. Unlike previous theory and research that focused on the United States, the present research examined the effects of political elite cues and affective polarization on support for policies to manage the COVID-19 pandemic in seven countries (n = 12,955): Brazil, Israel, Italy, South Korea, Sweden, the United Kingdom, and the United States. Across countries, cues from political elites polarized public attitudes toward COVID-19 policies. Liberal and conservative respondents supported policies proposed by ingroup politicians and parties more than the same policies from outgroup politicians and parties. Respondents disliked, distrusted, and felt cold toward outgroup political elites, whereas they liked, trusted, and felt warm toward both ingroup political elites and nonpartisan experts. This affective polarization was correlated with policy support. These findings imply that policies from bipartisan coalitions and nonpartisan experts would be less polarizing, enjoying broader public support. Indeed, across countries, policies from bipartisan coalitions and experts were more widely supported. A follow-up experiment replicated these findings among US respondents considering international vaccine distribution policies. The polarizing effects of partisan elites and affective polarization emerged across nations that vary in cultures, ideologies, and political systems. Contrary to some propositions, the United States was not exceptionally polarized. Rather, these results suggest that polarizing processes emerged simply from categorizing people into political ingroups and outgroups. Political elites drive polarization globally, but nonpartisan experts can help resolve the conflicts that arise fromit.