In the past decades, Deep Learning (DL) frameworks have demonstrated excellent performance in modeling nonlinear interactions and are a promising technique to move beyond physics-based models. In ...this context, super-resolution techniques may present an accurate approach as subfilter-scale (SFS) closure model for Large Eddy Simulations (LES) in premixed combustion. However, DL models need to perform accurately in a variety of physical regimes and generalize well beyond their training conditions. In this work, a super-resolution Generative Adversarial Network (GAN) is proposed as closure model for the unresolved subfilter-stress and scalar-flux tensors of the filtered reactive Navier–Stokes equations solved in LES. The model trained on a premixed methane/air jet flame is evaluated a-priori on similar configurations at different Reynolds and Karlovitz numbers. The GAN generalizes well at both lower and higher Reynolds numbers and outperforms existing algebraic models when the ratio between the filter size and the Kolmogorov scale is preserved. Moreover, extrapolation at a higher Karlovitz number is investigated indicating that the ratio between the filter size and the thermal flame thickness may not need to be conserved in order to achieve high correlation in terms of SFS field. Generalization studies obtained on substantially different flame conditions indicate that successful predictive abilities are demonstrated if the generalization criterion is matched. Finally, the reconstruction of a scalar quantity, different from that used during the training, is evaluated, revealing that the model is able to reconstruct scalar fields with large gradients that have not been explicitly used in the training. The a-priori investigations carried out assess whether out-of-sample predictions are even feasible in the first place, providing insights into the quantities that need to be conserved for the model to perform well between different regimes, and represent a crucial step toward future embedding into LES numerical solvers.
The Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Consortium is a collaborative network of researchers working together on a range of large-scale studies that integrate data from 70 ...institutions worldwide. Organized into Working Groups that tackle questions in neuroscience, genetics, and medicine, ENIGMA studies have analyzed neuroimaging data from over 12,826 subjects. In addition, data from 12,171 individuals were provided by the CHARGE consortium for replication of findings, in a total of 24,997 subjects. By meta-analyzing results from many sites, ENIGMA has detected factors that affect the brain that no individual site could detect on its own, and that require larger numbers of subjects than any individual neuroimaging study has currently collected. ENIGMA’s first project was a genome-wide association study identifying common variants in the genome associated with hippocampal volume or intracranial volume. Continuing work is exploring genetic associations with subcortical volumes (ENIGMA2) and white matter microstructure (ENIGMA-DTI). Working groups also focus on understanding how schizophrenia, bipolar illness, major depression and attention deficit/hyperactivity disorder (ADHD) affect the brain. We review the current progress of the ENIGMA Consortium, along with challenges and unexpected discoveries made on the way.
To study glycosidase activities of a Lactobacillus brevis strain and to isolate an intracellular β-glucosidase from this strain. Lactic acid bacteria (LAB) isolated from a commercially available ...starter culture preparation for malolactic fermentation were tested for β-glycosidase activities. A strain of Lact. brevis showing high intracellular β- d-glucosidase, β- d-xylosidase and α- l-arabinosidase activities was selected for purification and characterization of its β-glucosidase. The pure glucosidase from Lact. brevis has also side activities of xylosidase, arabinosidase and cellobiosidase. It is a homotetramer of 330 kDa and has an isoelectric point at pH 3·5. The Km for p-nitrophenyl-β- d-glucopyranoside and p-nitrophenyl-β- d-xylopyranoside is 0·22 and 1·14 mmol l⁻¹, respectively. The β-glucosidase activity was strongly inhibited by gluconic acid δ-lactone, partially by glucose and gluconate, but not by fructose. Ethanol and methanol were found to increase the activity up to twofold. The free enzyme was stable at pH 7·0 (t₁/₂ = 50 day) but not at pH 4·0 (t₁/₂ = 4 days). The β-glucosidase from Lact. brevis is widely different to that characterized from Lactobacillus casei ( Coulon et al. 1998 ) and Lactobacillus plantarum ( Sestelo et al. 2004 ). The high tolerance to fructose and ethanol, the low inhibitory effect of glucose on the enzyme activity and the good long-term stability could be of great interest for the release of aroma compounds during winemaking. Although the release of aroma compounds by LAB has been demonstrated by several authors, little information exists on the responsible enzymes. This study contains the first characterization of an intracellular β-glucosidase isolated from a wine-related strain of Lact. brevis.
Conservation of lotic fishes requires consideration of complex patterns among a changing mosaic of fish assemblage structure at multiple spatial scales. Studies have demonstrated the influence of ...localized competition and predation among stream fishes, but researchers have been largely unable to determine to what extent interspecific interactions act to control fish assemblage structure. Recent declines to geographic range and abundance of Plains Topminnow (Fundulus sciadicus (Cope)) have been anecdotally attributed to altered fish assemblages and potential competitive or predatory associations; however, important species interactions have yet to be identified. Variation among fish assemblage structure at 473 locations known to historically support Plains Topminnow was described in Nebraska to demonstrate the role of assemblage dynamics in regulating species occurrence. Nonrandom patterns of fish assemblage composition in terms of Plains Topminnow persistence were apparent statewide, and multiple relationships were recognized as regionally influential (e.g., Niobrara River: Largemouth Bass Micropterus salmoides (Lacépède)). Strong correlations were described relating Plains Topminnow extirpation to nonnative species establishment (Common Carp Cyprinus carpio (Linnaeus), Western Mosquitofish Gambusia affinis (Baird and Girard)), and several potential predatory (Esocidae, Channel Catfish Ictalurus punctatus (Rafinesque)) or competitive interactions (Western Mosquitofish, Bluegill Lepomis macrochirus (Rafinesque), Sand Shiner Notropis stramineus (Cope), Red Shiner Cyprinella lutrensis (Baird and Girard)) were identified. Positive relationships are attributed to similar reliance of particular abiotic conditions (Emerald Shiner Notropis atherinoides (Rafinesque)) or habitat types (Gasterosteidae, Green Sunfish Lepomis cyanellus (Rafinesque), Iowa Darter Etheostoma exile (Winn)). Other identified species will require research to elucidate potential biotic interactions with Plains Topminnow. Resultant models are hypothesized to reflect biotic processes, and thereby provide analytical insight into the long-term influence of fish assemblage structure on a rare species. Identified relationships provide preliminary recognition of potentially important interspecific interactions involving an unfamiliar species from which further hypotheses can be evaluated to ascertain casual relationships.
Plains topminnow Fundulus sciadicus are endemic to the Great Plains (USA), and because of declines in their geographic range and local abundance, are granted protection throughout their native range. ...Experimental reintroductions were conducted to improve conservation techniques and enhance the long-term outlook for plains topminnow persistence in Nebraska. Reintroductions were attempted at 17 extirpated stream reaches using low and high founder densities (no. of fish per suitable area) and during 2 seasons (spring and fall) to identify successful techniques for future conservation efforts. Reintroduced populations were sampled monthly (excluding winter) for 2 yr to monitor population persistence. Repeated presence-absence data was used to estimate persistence probabilities (1 - extinction probability), which we used to compare reintroduction strategy treatments. Plains topminnow were recaptured at 76% of reintroduction locations (1456 total individuals) and reproduction was observed at 35% of those sites. Catch rates at reintroduction sites varied substantially (range: 0 to 30.78 ind. per 100 m). The influence of season and founder density were minimal. Population persistence was more likely at sites stocked in fall at higher densities; however, wide confidence intervals suggest that individual site characteristics may more strongly influence population persistence. Similar population outcomes regardless of reintroduction strategy provide managers flexibility when making conservation decisions.
At present continental to global scale flood forecasting predicts at a point discharge, with little attention to detail and accuracy of local scale inundation predictions. Yet, inundation variables ...are of interest and all flood impacts are inherently local in nature. This paper proposes a large‐scale flood inundation ensemble forecasting model that uses best available data and modeling approaches in data scarce areas. The model was built for the Lower Zambezi River to demonstrate current flood inundation forecasting capabilities in large data‐scarce regions. ECMWF ensemble forecast (ENS) data were used to force the VIC (Variable Infiltration Capacity) hydrologic model, which simulated and routed daily flows to the input boundary locations of a 2‐D hydrodynamic model. Efficient hydrodynamic modeling over large areas still requires model grid resolutions that are typically larger than the width of channels that play a key role in flood wave propagation. We therefore employed a novel subgrid channel scheme to describe the river network in detail while representing the floodplain at an appropriate scale. The modeling system was calibrated using channel water levels from satellite laser altimetry and then applied to predict the February 2007 Mozambique floods. Model evaluation showed that simulated flood edge cells were within a distance of between one and two model resolutions compared to an observed flood edge and inundation area agreement was on average 86%. Our study highlights that physically plausible parameter values and satisfactory performance can be achieved at spatial scales ranging from tens to several hundreds of thousands of km2 and at model grid resolutions up to several km2.
Key Points
A first large scale, yet detailed flood inundation forecasting model
Although large scale, the proposed model agrees with high accuracy observations
The model was fully tested in a large data‐scarce, flood‐prone river basin
An upper limit for aircraft-produced perturbations to aerosols and gaseous exhaust products in the upper troposphere and lower stratosphere (UT/LS) is derived using the 1992 aviation fuel tracer ...simulation performed by eleven global atmospheric models. Key findings are that subsonic aircraft emissions: (1) have not been responsible for the observed water vapor trends at 40degN; (2) could be a significant source of soot mass near 12 km, but not at 20 km; (3) might cause a noticeable increase in the background sulfate aerosol surface area and number densities (but not mass density) near the northern mid-latitude tropopause; and (4) could provide a global, annual mean top of the atmosphere radiative forcing up to +0.006 W/sq m and -0.013 W/sq m due to emitted soot and sulfur, respectively.
The amygdala is a medial temporal lobe structure implicated in social and emotional regulation. In typical development (TD), the amygdala continues to increase volumetrically throughout childhood and ...into adulthood, while other brain structures are stable or decreasing in volume. In autism spectrum disorder (ASD), the amygdala undergoes rapid early growth, making it volumetrically larger in children with ASD compared to TD children. Here we explore: (a) if dendritic arborization in the amygdala follows the pattern of protracted growth in TD and early overgrowth in ASD and (b), if spine density in the amygdala in ASD cases differs from TD from youth to adulthood. The amygdala from 32 postmortem human brains (7–46 years of age) were stained using a Golgi‐Kopsch impregnation. Ten principal neurons per case were selected in the lateral nucleus and traced using Neurolucida software in their entirety. We found that both ASD and TD individuals show a similar pattern of increasing dendritic length with age well into adulthood. However, spine density is (a) greater in young ASD cases compared to age‐matched TD controls (<18 years old) and (b) decreases in the amygdala as people with ASD age into adulthood, a phenomenon not found in TD. Therefore, by adulthood, there is no observable difference in spine density in the amygdala between ASD and TD age‐matched adults (≥18 years old). Our findings highlight the unique growth trajectory of the amygdala and suggest that spine density may contribute to aberrant development and function of the amygdala in children with ASD.
Here we demonstrate the density of spines in the amygdala is greater in young children with ASD than typically developing peers. This phenomenon normalizes with age such that there is no difference in spine density between adults with ASD and typically developing adults.
Brain charts for the human lifespan Anderson, K M; Adamson, C; Adler, S ...
Nature (London),
04/2022, Letnik:
604, Številka:
7906
Journal Article
Recenzirano
Odprti dostop
Over the past few decades, neuroimaging has become a ubiquitous tool in basic research and clinical studies of the human brain. However, no reference standards currently exist to quantify individual ...differences in neuroimaging metrics over time, in contrast to growth charts for anthropometric traits such as height and weight
. Here we assemble an interactive open resource to benchmark brain morphology derived from any current or future sample of MRI data ( http://www.brainchart.io/ ). With the goal of basing these reference charts on the largest and most inclusive dataset available, acknowledging limitations due to known biases of MRI studies relative to the diversity of the global population, we aggregated 123,984 MRI scans, across more than 100 primary studies, from 101,457 human participants between 115 days post-conception to 100 years of age. MRI metrics were quantified by centile scores, relative to non-linear trajectories
of brain structural changes, and rates of change, over the lifespan. Brain charts identified previously unreported neurodevelopmental milestones
, showed high stability of individuals across longitudinal assessments, and demonstrated robustness to technical and methodological differences between primary studies. Centile scores showed increased heritability compared with non-centiled MRI phenotypes, and provided a standardized measure of atypical brain structure that revealed patterns of neuroanatomical variation across neurological and psychiatric disorders. In summary, brain charts are an essential step towards robust quantification of individual variation benchmarked to normative trajectories in multiple, commonly used neuroimaging phenotypes.
Abstract
The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole magnet, has searched for axions in the 19.74
μ
eV to 22.47
μ
eV mass range. The detection concept follows the ...Sikivie haloscope principle, where Dark Matter axions convert into photons within a resonator immersed in a magnetic field. The CAST-CAPP resonator is an array of four individual rectangular cavities inserted in a strong dipole magnet, phase-matched to maximize the detection sensitivity. Here we report on the data acquired for 4124 h from 2019 to 2021. Each cavity is equipped with a fast frequency tuning mechanism of 10 MHz/ min between 4.774 GHz and 5.434 GHz. In the present work, we exclude axion-photon couplings for virialized galactic axions down to
g
a
γ
γ
= 8 × 10
−14
GeV
−1
at the 90% confidence level. The here implemented phase-matching technique also allows for future large-scale upgrades.
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