bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vivo simultaneous nonlinear absorption Raman and fluorescence (SNARF) imaging of mouse brain cortical structures
Authors: Francis Andrew T. , Manifold Bryce , Carlson Elena C. , Hu Ruoqian , Hill Andrew H. , Men Shuaiqian , Fu Dan 
Published: March 2022

AbstractLabel-free multiphoton microscopy is a powerful platform for biomedical imaging. Recent advancements have demonstrated the capabilities of transient absorption microscopy (TAM) for label-free quantification of hemoglobin and stimulated Raman scattering (SRS) microscopy for pathological assessment of label-free virtual histochemical staining. We propose the combination of TAM and SRS with two-photon excited fluorescence (TPEF) to characterize, quantify, and compare hemodynamics, vessel structure, cell density, and cell identity in vivo between age groups. In this study, we construct a simultaneous nonlinear absorption, Raman, and fluorescence (SNARF) microscope with the highest reported in vivo imaging depth for SRS and TAM at 250–280 μm to enable these multimodal measurements. Using machine learning, we predict capillary-lining cell identities with 90% accuracy based on nuclear morphology and capillary relationship. The microscope and methodology outlined herein provides an exciting route to study several research topics, including neurovascular coupling, blood-brain barrier, and neurodegenerative diseases.
The SARS-CoV-2 Alpha variant exhibits comparable fitness to the D614G strain in a Syrian hamster model
Authors: Cochin Maxime , Luciani Léa , Touret Franck , Driouich Jean-Sélim , Petit Paul-Rémi , Moureau Grégory , Baronti Cécile , Laprie Caroline , Thirion Laurence , Maes Piet , Boudewijns Robbert , Neyts Johan , de Lamballerie Xavier , Nougairède Antoine 
Published: March 2022

AbstractLate 2020, SARS-CoV-2 Alpha variant emerged in United Kingdom and gradually replaced G614 strains initially involved in the global spread of the pandemic. In this study, we use a Syrian hamster model to compare a clinical strain of Alpha variant with an ancestral G614 strain. The Alpha variant succeed to infect animals and to induce a pathology that mimics COVID-19. However, both strains replicate to almost the same level and induced a comparable disease and immune response. A slight fitness advantage is noted for the G614 strain during competition and transmission experiments. These data do not corroborate the epidemiological situation observed during the first half of 2021 in humans nor reports that showed a more rapid replication of Alpha variant in human reconstituted bronchial epithelium. This study highlights the need to combine data from different laboratories using various animal models to decipher the biological properties of newly emerging SARS-CoV-2 variants.
Self-replicating subduction zone initiation by polarity reversal
Authors: Almeida Jaime , Riel Nicolas , Rosas Filipe M. , Duarte João C. , Kaus Boris 
Published: March 2022

AbstractSubduction zones have recurrently formed on Earth. Previous studies have, however, suggested that they are unlikely to start in the interior of a pristine ocean. Instead, they seem to be more likely to form from another pre-existing subduction zone. One widely cited conceptual model to start new subduction zones is polarity reversal, resulting from the shutdown of a pre-existent subduction zone due to the arrival of a buoyant block at the trench. However, the dynamic conditions by which this process occurs remain elusive. Here, we present 3D numerical models of subduction zone initiation by polarity reversal resulting from the arrival of an oceanic plateau at the trench. Our results show that this process is more likely to occur for old subducting plates and narrow plateaus, and that new subduction zones can form from previous ones in a self-replicating manner, without requiring any other external tectonic forcing.
Hydrothermal fluid flow triggered by an earthquake in Iceland
Authors: Geoffroy Laurent , Dorbath Catherine , Ágústsson Kristján , Kristjánsdóttir Sigríður , Flóvenz Ólafur G. , Doubre Cécile , Gudmundsson Ólafur , Barreyre Thibaut , Bazin Sara , Franco Aurore 
Published: March 2022

AbstractMicroearthquake hypocenters were analyzed in the Krýsuvík geothermal area in SW-Iceland with data taken from two consecutive passive seismic surveys, 2005 and 2009. Five years prior to the 2005 survey, this area was struck by an earthquake initiating a major top-to-bottom fluid migration in the upper crust. We observe from our surveys a complex bottom-to-top migration of seismicity with time following this fluid penetration, suggesting the migration of a pore pressure front controlled by the upper-crust fracture system. We interpret these data as the time and space development of high-temperature hydrothermal cells from a deep upper crustal fluid reservoir in the supercritical field. These results provide an insight into the coupling mechanisms between active tectonics and fluid flow in upper-crustal extensional systems with high thermal flux.
Ice viscosity is more sensitive to stress than commonly assumed
Authors: Millstein Joanna D. , Minchew Brent M. , Pegler Samuel S. 
Published: March 2022

AbstractAccurate representation of the viscous flow of ice is fundamental to understanding glacier dynamics and projecting sea-level rise. Ice viscosity is often described by a simple but largely untested and uncalibrated constitutive relation, Glen’s Flow Law, wherein the rate of deformation is proportional to stress raised to the powern. The valuen = 3 is commonly prescribed in ice-flow models, though observations and experiments support a range of values across stresses and temperatures found on Earth. Here, we leverage recent remotely-sensed observations of Antarctic ice shelves to show that Glen’s Flow Law approximates the viscous flow of ice withn = 4.1 ± 0.4 in fast-flowing areas. The viscosity and flow rate of ice are therefore more sensitive to changes in stress than most ice-flow models allow. By calibrating the governing equation of ice deformation, our result is a pathway towards improving projections of future glacier change.
NetGAM: Using generalized additive models to improve the predictive power of ecological network analyses constructed using time-series data
Authors: Gleich Samantha J , Cram Jacob A , Weissman J L , Caron David A 
Published: March 2022

Abstract
Ecological network analyses are used to identify potential biotic interactions between microorganisms from species abundance data. These analyses are often carried out using time-series data; however, time-series networks have unique statistical challenges. Time-dependent species abundance data can lead to species co-occurrence patterns that are not a result of direct, biotic associations and may therefore result in inaccurate network predictions. Here, we describe a generalize additive model (GAM)-based data transformation that removes time-series signals from species abundance data prior to running network analyses. Validation of the transformation was carried out by generating mock, time-series datasets, with an underlying covariance structure, running network analyses on these datasets with and without our GAM transformation, and comparing the network outputs to the known covariance structure of the simulated data. The results revealed that seasonal abundance patterns substantially decreased the accuracy of the inferred networks. In addition, the GAM transformation increased the predictive power (F1 score) of inferred ecological networks on average and improved the ability of network inference methods to capture important features of network structure. This study underscores the importance of considering temporal features when carrying out network analyses and describes a simple, effective tool that can be used to improve results.
Selective treatment of intracellular bacterial infections using host cell-targeted bioorthogonal nanozymes
Authors: Hardie Joseph , Makabenta Jessa Marie , Gupta Aarohi , Huang Rui , Cao-Milán Roberto , Goswami Ritabrita , Zhang Xianzhi , Abdulpurkar Parvati , Farkas Michelle E. , Rotello Vincent M. 
Published: March 2022

Macrophage-targeted bioorthogonal nanozyme designed to generate antibiotics at the site of infection. Nanozymes had targeted uptake by macrophages through mannose functionalization, then generated antibiotics to specifically kill infectious bacteria.
Memristors based on carbon dots for learning activities in artificial biosynapse applications
Authors: Li Xiaoyu , Pei Yifei , Zhao Ying , Song Haoqiang , Zhao Jianhui , Yan Lei , He Hui , Lu Siyu , Yan Xiaobing 
Published: March 2022

Carbon quantum dots (CDs) were doped into the memristor to prepare Ag/HfO2/CDs/Pt devices, which improved the uniformity of device parameters and accomplished simulations of supervised learning, interest-based learning activities and preview and review learning method.
Distribution probability‐based self‐adaption metric learning for person re‐identification
Authors: Ren Yutao , Huang Zhangcan 
Published: March 2022

AbstractPerson re‐identification addresses the problem of pedestrian image matching in a non‐overlapped surveillance network. Traditional metric learning methods try to learn a fixed pedestrian images matching metric model. However, existing metric learning‐based methods have the problem of overfitting the training data. In order to solve this problem, a sample‐specific metric learning‐based method is proposed. In the perspective of probability distribution, the over‐fitting problem is attributed to the problem that the generalisation ability of projection features is weak. Firstly, the proposed method learns a metric subspace, which projects the raw feature to a discriminative subspace. Then, a projection feature selection method is established based on the probability distribution of positive image pairs. According to the proposed method, the probability that the test samples following the training data distribution is closely related to the adaptability. The proposed projection feature selection method selects different projection features for each individual's similarity distance measure. Finally, extensive experiments on four published datasets verify the effectiveness of the proposed metric learning method. It performs favourably against the comparison methods, especially on the rank‐1 rate.
Detection of period-spacing patterns due to the gravity modes of rotating dwarfs in the TESS southern continuous viewing zone
Authors: Garcia S. , Van Reeth T. , De Ridder J. , Tkachenko A. , IJspeert L. , Aerts C. 
Published: March 2022

Context.The theory of stellar evolution presents shortcomings when confronted with asteroseismic probes of interior physical properties. The differences between observations and theory are often great because stellar models have mainly been calibrated from observables connected to the surface of stars. Period-spacing patterns caused by gravity modes are a particularly powerful asteroseismic tool that are useful for probing the near-core rotation and mixing of chemical elements in main-sequence stars with convective cores.Aims.We aim to compose a catalog of intermediate-mass stars in the Transiting Exoplanet Survey Satellite (TESS) southern continuous viewing zone (CVZ) to reveal period-spacing patterns caused by gravity modes for use in future asteroseismic modeling.Methods.TESS full frame images (FFI) were inspected to select stars of intermediate- and high-mass using color-magnitude criteria. Light curves were extracted from custom masks per star, adopting stringent constraints on the aperture masks and contamination. The extracted light curves were subject to iterative prewhitening to detect gravity modes. We developed a method relying on the assumption that period spacings are an approximately linear function of the mode periods to build a template pattern. This template was used to extract the patterns and their uncertainties, relying on a bootstrap approach.Results.Our TESS catalog of high-quality period-spacing patterns is the first of its kind and contains 140 gravity-mode patterns in 106 γ Dor stars and two slowly pulsating B-type (SPB) stars. Half of these patterns contain seven or more measured mode periods and the longest pattern contains 20 modes. We provide the community with a convenient software tool to search for period-spacing patterns and to process the extracted light curves.Conclusions.Our catalog offers a fruitful starting point for future gravity-mode asteroseismology of rotating dwarfs with convective cores in the southern hemisphere.
CHEMOUT: CHEMical complexity in star-forming regions of the OUTer Galaxy
Authors: Fontani F. , Colzi L. , Bizzocchi L. , Rivilla V. M. , Elia D. , Beltrán M. T. , Caselli P. , Magrini L. , Sánchez-Monge A. , Testi L. , Romano D. 
Published: March 2022

Context. The outer Galaxy is an environment with metallicity lower than the Solar one. Because of this, the formation and survival of molecules in star-forming regions located in the inner and outer Galaxy is expected to be different.
Aims. To gain an understanding on how chemistry changes throughout the Milky Way, it is crucial to observe outer Galaxy star-forming regions to constrain models adapted for lower metallicity environments.
Methods. In this paper, we present a new observational project: chemical complexity in star-forming regions of the outer Galaxy (CHEMOUT). The goal is to unveil the chemical composition in 35 dense molecular clouds associated with star-forming regions of the outer Galaxy through observations obtained with the Institut de RadioAstronomie Millimétrique 30 m telescope in specific 3 mm and 2 mm spectral windows.
Results. In this first paper, we present the sample, and report the detection at 3 mm of simple organic species HCO+, H13CO+, HCN, c-C3H2, HCO, C4H, and HCS+, of the complex hydrocarbon CH3CCH, and of SiO, CCS, and SO. From the optically thin line JKa ,Kb = 21,2 − 10,1 of c-C3 H2 we estimate new kinematic heliocentric and Galactocentric distances based on an updated rotation curve of the Galaxy. The detection of the molecular tracers does not seem to have a clear dependence on the Galactocentric distance. Moreover, with the purpose of investigating the occurrence of outflows and investigate the association with protostellar activity, we analyse the HCO+ line profiles. We find high velocity wings in ~71% of the targets, and their occurrence does not depend on the Galactocentric distance.
Conclusions. Our results, confirmed by a statistical analysis, show that the presence of organic molecules and tracers of protostellar activity is ubiquitous in the low metallicity environment of the outer Galaxy. Based on this and on the additional evidence that small, terrestrial planets are omnipresent in the Galaxy, we support previous claims that the definition of the Galactic habitable zone should be subject to further discussion in view of the ubiquitous capacity of the interstellar medium to form organic molecules.
Nanoflare distributions over solar cycle 24 based on SDO/AIA differential emission measure observations
Authors: Purkhart Stefan , Veronig Astrid M. 
Published: March 2022

Aims. Nanoflares in quiet-Sun regions during solar cycle 24 are studied with the best available plasma diagnostics to derive their energy distribution and contribution to coronal heating during different levels of solar activity.
Methods. Extreme ultraviolet filters of the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) were used. We analyzed 30 AIA/SDO image series between 2011 and 2018, each covering a 400″ × 400″ quiet-Sun field-of-view of over two hours with a 12-s cadence. Differential emission measure (DEM) analysis was used to derive the emission measure (EM) and temperature evolution for each pixel. We detected nanoflares as EM enhancements using a threshold-based algorithm and derived their thermal energy from the DEM observations.
Results. Nanoflare energy distributions follow power laws that show slight variations in steepness (α = 2.02–2.47), but no correlation to the solar activity level. The combined nanoflare distribution of all data sets covers five orders of magnitude in event energies (1024 − 1029 erg) with a power-law index α = 2.28 ± 0.03. The derived mean energy flux of (3.7 ± 1.6)×104 erg cm−2 s−1 is one order of magnitude smaller than the coronal heating requirement. We found no correlation between the derived energy flux and solar activity. Analysis of the spatial distribution reveals clusters of high energy flux (up to 3 × 105 erg cm−2 s−1) surrounded by extended regions with lower activity. Comparisons with magnetograms from the Helioseismic and Magnetic Imager demonstrate that high-activity clusters are preferentially located in the magnetic network and above regions of enhanced magnetic flux density.
Conclusions. The steep power-law slope (α > 2) suggests that the total energy in the flare energy distribution is dominated by the smallest events, that is to say nanoflares. We demonstrate that in the quiet-Sun, the nanoflare distributions and their contribution to coronal heating does not vary over the solar cycle.
Nutritive value and occurrence of mycotoxins in various forage silages sampled at different levels in dairy farm silos
Authors: Mannai Amal , Juan Cristina , Mañes Jordi , Ben Salem Hichem 
Published: March 2022

Context Consumers require nutritious and safe animal products, particularly milk and meat. Forage silage is a major source of feed for dairy cattle. However, inappropriate silo preparation and management can affect silage nutritional quality and may lead to fungal growth and mycotoxin production. Aims We aimed to determine the nutritional quality of different forage silages in dairy farms from four regions in northern Tunisia where silage production is a common practice, and to screen for the presence and concentration of 23 mycotoxins. Methods Six different forage silage types from 27 silos were sampled 100 days after ensiling. Samples were taken from upper, middle and lower sections of the silo. The pH and nutritional values of the silages were determined. The QuEChER method was used to extract mycotoxins, and they were identified and quantified through liquid or gas chromatography with tandem mass spectrometry. Key results Silage pH ranged from 4.4 to 7.8, and dry matter content of forage biomass from 15% to 47%. Values of pH of silage samples varied among the silo levels (P = 0.001), whereas nutrient contents of silage biomass were similar among the three levels. Only five Fusarium mycotoxins (deoxynivalenol, two enniatins, beauvercin, HT-2 toxin) were detected at different concentrations depending on the silo level. Oat, oat + triticale and oat + sulla silages were the most heavily contaminated with mycotoxins. Biomass in the upper silo level was the most co-contaminated. Conclusions High pH (>4) and dry matter content (>30%) indicate low quality silages; therefore, the silages were generally of low quality. Although the evaluated silages were contaminated with five of the targeted mycotoxins, their concentrations were so low that they do not represent a risk to the health of dairy cattle. Implications Forage biomass should have a dry matter content of 20–30% on the day of silo filling. It is important to sample silage from the upper, middle and lower sections of the silo to screen for mycotoxins. In future studies, the transfer of detected mycotoxins to milk should be determined.
Genetic parameters for methane emissions in Australian sheep measured in portable accumulation chambers in grazing and controlled environments
Authors: Wahinya P. K. , Oddy V. H. , Dominik S. , Brown D. J. , Macleay C. A. , Paganoni B. , Thompson A. N. , Donaldson A. J. , Austin K. , Cameron M. , van der Werf J. H. J. 
Published: March 2022

Context Genotype by environment interaction or sire re-ranking between measurements of methane emission in different environments or from using different measurement protocols can affect the efficiency of selection strategies to abate methane emission. Aim This study tested the hypothesis that measurements of methane emission from grazing sheep under field conditions, where the feed intake is unknown, are genetically correlated to measurements in a controlled environment where feed intake is known. Methods Data on emission of methane and carbon dioxide and uptake of oxygen were measured using portable accumulation chambers from 499 animals in a controlled environment in New South Wales and 1382 animals in a grazing environment in Western Australia were analysed. Genetic linkage between both environments was provided by 140 sires with progeny in both environments. Multi-variate animal models were used to estimate genetic parameters for the three gas traits corrected for liveweight. Genetic groups were fitted in the models to account for breed differences. Genetic correlations between the field and controlled environments for the three traits were estimated using bivariate models. Key results Animals in the controlled environment had higher methane emission compared to the animals in the field environment (37.0 ± s.d 9.3 and 35.3 ± s.d 9.4 for two protocols vs 12.9 ± s.d 5.1 and 14.6 ± s.d 4.8 mL/min for lambs and ewes (±s.d); P < 0.05) but carbon dioxide emission and oxygen uptake did not significantly differ. The heritability estimates for methane emission, carbon dioxide emission and oxygen uptake were 0.15, 0.06 and 0.11 for the controlled environment and 0.17, 0.27 and 0.35 for the field environment. The repeatability for the traits in the controlled environment ranged from 0.51 to 0.59 and from 0.24 to 0.38 in the field environment. Genetic correlations were high (0.85–0.99) but with high standard errors. Conclusion Methane emission phenotypes measured using portable accumulation chambers in grazing sheep can be used in genetic evaluation to estimate breeding values for genetic improvement of emission related traits. The combined measurement protocol-environment did not lead to re-ranking of sires. Implication These results suggest that both phenotypes could be used in selection for reduced methane emission in grazing sheep. However, this needs to be consolidated using a larger number of animals and sires with larger progeny groups in different environments.
Adjusting grain boundary within NiCo2O4 rod arrays by phosphating reaction for efficient hydrogen production
Authors: Ma Xianguo , Wang Zining , Wang Zhihao , Cui Mengqi , Wang Hui , Ren Jianwei , Karimzadeh Sina 
Published: March 2022

Abstract
In this work, the density and electronic structures of the metal active sites in NiCo2O4 nanorod arrays were concurrently tuned by controlling the sample’s exposure time in a phosphorization process. The results showed that both the density and electronic structure of the active adsorption sites played a key role towards the catalytic activity for water splitting to produce hydrogen. The optimal catalyst exhibited 81 mV overpotential for hydrogen evolution reaction (HER) at 10 mA cm−2 and 313 mV overpotential towards oxygen evolution reaction at 50 mA cm−2. The assembled electrode delivered a current density of 50 mA cm−2 at 1.694 V in a fully functional water electrolyzer. The further results of theoretical density functional theory calculations revealed the doping of P elements lowered down the H adsorption energies involved in the water splitting process on the various active sites of P-NiCo2O4-10 catalyst, and thus enhanced its HER catalytic activities.