Schizophrenia is a devastating neurodevelopmental disorder with a complex genetic etiology. Widespread cortical gray matter loss has been observed in patients and prodromal samples. However, it ...remains unresolved whether schizophrenia-associated cortical structure variations arise due to disease etiology or secondary to the illness. Here we address this question using a partitioning-based heritability analysis of genome-wide single-nucleotide polymorphism (SNP) and neuroimaging data from 1750 healthy individuals. We find that schizophrenia-associated genetic variants explain a significantly enriched proportion of trait heritability in eight brain phenotypes (false discovery rate=10%). In particular, intracranial volume and left superior frontal gyrus thickness exhibit significant and robust associations with schizophrenia genetic risk under varying SNP selection conditions. Cross-disorder comparison suggests that the neurogenetic architecture of schizophrenia-associated brain regions is, at least in part, shared with other psychiatric disorders. Our study highlights key neuroanatomical correlates of schizophrenia genetic risk in the general population. These may provide fundamental insights into the complex pathophysiology of the illness, and a potential link to neurocognitive deficits shaping the disorder.
How do we construct national identities in discourse? Which topics, which discursive strategies and which linguistic devices are employed to construct national sameness and uniqueness on the one ...hand, and differences to other national collectives on the o
Recent work has demonstrated that subject motion produces systematic biases in the metrics computed by widely used morphometry software packages, even when the motion is too small to produce ...noticeable image artifacts. In the common situation where the control population exhibits different behaviors in the scanner when compared to the experimental population, these systematic measurement biases may produce significant confounds for between-group analyses, leading to erroneous conclusions about group differences. While previous work has shown that prospective motion correction can improve perceived image quality, here we demonstrate that, in healthy subjects performing a variety of directed motions, the use of the volumetric navigator (vNav) prospective motion correction system significantly reduces the motion-induced bias and variance in morphometry.
•Motion correction with volumetric navigators (vNavs) reduces motion-induced biases in gray matter and brain volume estimates.•Additionally, motion correction with vNavs reduces variance in morphometry measures due to subject motion.•Our methods can be used to evaluate the impact of motion on studies with different MRI scanner equipment or pulse sequences.
Motion analysis is used in computer vision to understand the behaviour of moving objects in sequences of images. Optimising the interpretation of dynamic biological systems requires accurate and ...precise motion tracking as well as efficient representations of high-dimensional motion trajectories so that these can be used for prediction tasks. Here we use image sequences of the heart, acquired using cardiac magnetic resonance imaging, to create time-resolved three-dimensional segmentations using a fully convolutional network trained on anatomical shape priors. This dense motion model formed the input to a supervised denoising autoencoder (4D
), which is a hybrid network consisting of an autoencoder that learns a task-specific latent code representation trained on observed outcome data, yielding a latent representation optimised for survival prediction. To handle right-censored survival outcomes, our network used a Cox partial likelihood loss function. In a study of 302 patients the predictive accuracy (quantified by Harrell's C-index) was significantly higher (p = .0012) for our model C=0.75 (95% CI: 0.70 - 0.79) than the human benchmark of C=0.59 (95% CI: 0.53 - 0.65). This work demonstrates how a complex computer vision task using high-dimensional medical image data can efficiently predict human survival.
To develop evidence-based recommendations for the diagnosis of hand osteoarthritis (OA).
The multidisciplinary guideline development group, representing 15 European countries, generated 10 key ...propositions regarding diagnosis using a Delphi consensus approach. For each recommendation, research evidence was searched for systematically. Whenever possible, the sensitivity, specificity and likelihood ratio (LR) were calculated; relative risk and odds ratios were estimated for risk factors for hand OA. Quality of evidence was categorised using the European League Against Rheumatism (EULAR) hierarchy, and strength of recommendation was assessed by the EULAR visual analogue scale.
Diagnostic topics included clinical manifestations, radiographic features, subgroups, differential diagnosis, laboratory tests, risk factors and comorbidities. The sensitivity, specificity and LR varied between tests depending upon the cut-off level, gold standard and controls. Overall, no single test could be used to define hand OA on its own (LR <10) but a composite of the tests greatly increased the chance of the diagnosis. The probability of a subject having hand OA was 20% when Heberden nodes alone were present, but this increased to 88% when in addition the subject was over 40 years old, had a family history of nodes and had joint space narrowing in any finger joint.
Ten key recommendations for diagnosis of hand OA were developed using research evidence and expert consensus. Diagnosis of hand OA should be based on assessment of a composite of features.
Characterizing past climate states is crucial for understanding the future consequences of ongoing greenhouse gas emissions. Here, we revisit the benchmark time series for deep ocean temperature ...across the past 65 million years using clumped isotope thermometry. Our temperature estimates from the deep Atlantic Ocean are overall much warmer compared with oxygen isotope–based reconstructions, highlighting the likely influence of changes in deep ocean pH and/or seawater oxygen isotope composition on classical oxygen isotope records of the Cenozoic. In addition, our data reveal previously unrecognized large swings in deep ocean temperature during early Eocene acute greenhouse warmth. Our results call for a reassessment of the Cenozoic history of ocean temperatures to achieve a more accurate understanding of the nature of climatic responses to tectonic events and variable greenhouse forcing.
Warmer than realized
Past climates may hold important clues about how the planet might respond to ongoing climate warming. Meckler
et al
. use clumped isotope thermometry on benthic foraminifera to reinterpret the record of the deep ocean temperature over the past 65 million years. They found that deep ocean temperatures were generally higher and more variable than earlier work suggests. Their results have implications for our understanding of deep sea temperature responses to atmospheric carbon dioxide concentrations, climate sensitivity, and ocean structure during times of minimal continental ice. —HJS
Greenhouse climates over the past 65 million years had warmer and more variable deep ocean temperatures than was previously believed.
Less than half of anthropogenic carbon dioxide emissions remain in the atmosphere. While carbon balance models imply large carbon uptake in tropical forests, direct on-the-ground observations are ...still lacking in Southeast Asia. Here, using long-term plot monitoring records of up to half a century, we find that intact forests in Borneo gained 0.43 Mg C ha
per year (95% CI 0.14-0.72, mean period 1988-2010) above-ground live biomass. These results closely match those from African and Amazonian plot networks, suggesting that the world's remaining intact tropical forests are now en masse out-of-equilibrium. Although both pan-tropical and long-term, the sink in remaining intact forests appears vulnerable to climate and land use changes. Across Borneo the 1997-1998 El Niño drought temporarily halted the carbon sink by increasing tree mortality, while fragmentation persistently offset the sink and turned many edge-affected forests into a carbon source to the atmosphere.
We present high angular resolution observations (0''.5 x 0''.3) carried out with the Submillimeter Array (SMA) toward the AFGL2591 high-mass star-forming region. Our SMA images reveal a clear ...chemical segregation within the AFGL2591 VLA 3 hot core, where different molecular species (Types I, II, and III) appear distributed in three concentric shells. This is the first time that such a chemical segregation is ever reported at linear scales < or =, slant3000 AU within a hot core. While Type I species (H sub(2)S and super(13)CS) peak at the AFGL2591 VLA 3 protostar, Type II molecules (HC sub(3)N, OCS, SO, and SO sub(2)) show a double-peaked structure circumventing the continuum peak. Type III species, represented by CH sub(3)OH, form a ring-like structure surrounding the continuum emission. The excitation temperatures of SO sub(2), HC sub(3)N, and CH sub(3)OH (185 + or - 11 K, 150 + or - 20 K, and 124 + or - 12 K, respectively) show a temperature gradient within the AFGL2591 VLA 3 envelope, consistent with previous observations and modeling of the source. By combining the H sub(2)S, SO sub(2), and CH sub(3)OH images, representative of the three concentric shells, we find that the global kinematics of the molecular gas follow Keplerian-like rotation around a 40 M sub(middot in circle) star. The chemical segregation observed toward AFGL2591 VLA 3 is explained by the combination of molecular UV photodissociation and a high-temperature (~1000 K) gas-phase chemistry within the low extinction innermost region in the AFGL2591 VLA 3 hot core.
The North American Ice Sheet Complex (NAISC; consisting of the Laurentide, Cordilleran and Innuitian ice sheets) was the largest ice mass to repeatedly grow and decay in the Northern Hemisphere ...during the Quaternary. Understanding its pattern of retreat following the Last Glacial Maximum is critical for studying many facets of the Late Quaternary, including ice sheet behaviour, the evolution of Holocene landscapes, sea level, atmospheric circulation, and the peopling of the Americas. Currently, the most up-to-date and authoritative margin chronology for the entire ice sheet complex is featured in two publications (Geological Survey of Canada Open File 1574 Dyke et al., 2003; ‘Quaternary Glaciations – Extent and Chronology, Part II’ Dyke, 2004). These often-cited datasets track ice margin recession in 36 time slices spanning 18 ka to 1 ka (all ages in uncalibrated radiocarbon years) using a combination of geomorphology, stratigraphy and radiocarbon dating. However, by virtue of being over 15 years old, the ice margin chronology requires updating to reflect new work and important revisions. This paper updates the aforementioned 36 ice margin maps to reflect new data from regional studies. We also update the original radiocarbon dataset from the 2003/2004 papers with 1541 new ages to reflect work up to and including 2018. A major revision is made to the 18 ka ice margin, where Banks and Eglinton islands (once considered to be glacial refugia) are now shown to be fully glaciated. Our updated 18 ka ice sheet increased in areal extent from 17.81 to 18.37 million km2, which is an increase of 3.1% in spatial coverage of the NAISC at that time. Elsewhere, we also summarize, region-by-region, significant changes to the deglaciation sequence. This paper integrates new information provided by regional experts and radiocarbon data into the deglaciation sequence while maintaining consistency with the original ice margin positions of Dyke et al. (2003) and Dyke (2004) where new information is lacking; this is a pragmatic solution to satisfy the needs of a Quaternary research community that requires up-to-date knowledge of the pattern of ice margin recession of what was once the world’s largest ice mass. The 36 updated isochrones are available in PDF and shapefile format, together with a spreadsheet of the expanded radiocarbon dataset (n = 5195 ages) and estimates of uncertainty for each interval.
•Updated deglaciation sequence using regional studies/expertise and radiocarbon data.•Region-by-region overview of significant ice margin changes from 18 ka to 1 ka.•New 18 ka 14C (∼21.7 ka cal.) ice sheet is 3.1% larger than previous estimates.•36 updated isochrones (PDFs/shapefiles) and radiocarbon dataset (n = 5195 ages).•Ice margins of Dyke et al. (2003) retained where new information is lacking.
Abstract
When electric conductors differ from their mirror image, unusual chiral transport coefficients appear that are forbidden in achiral metals, such as a non-linear electric response known as ...electronic magnetochiral anisotropy (eMChA)
1–6
. Although chiral transport signatures are allowed by symmetry in many conductors without a centre of inversion, they reach appreciable levels only in rare cases in which an exceptionally strong chiral coupling to the itinerant electrons is present. So far, observations of chiral transport have been limited to materials in which the atomic positions strongly break mirror symmetries. Here, we report chiral transport in the centrosymmetric layered kagome metal CsV
3
Sb
5
observed via second-harmonic generation under an in-plane magnetic field. The eMChA signal becomes significant only at temperatures below
$${T}^{{\prime} }\approx $$
T
′
≈
35 K, deep within the charge-ordered state of CsV
3
Sb
5
(
T
CDW
≈ 94 K). This temperature dependence reveals a direct correspondence between electronic chirality, unidirectional charge order
7
and spontaneous time-reversal symmetry breaking due to putative orbital loop currents
8–10
. We show that the chirality is set by the out-of-plane field component and that a transition from left- to right-handed transport can be induced by changing the field sign. CsV
3
Sb
5
is the first material in which strong chiral transport can be controlled and switched by small magnetic field changes, in stark contrast to structurally chiral materials, which is a prerequisite for applications in chiral electronics.
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