bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphometric analysis of stem-group mollusks from the northern Yangtze Craton, China
Authors: Pang Yanchun , Steiner Michael , Yang Ben , Hou Mingcai , Ogg James G. , Ji Wenhu , Hu Qiang , Liang Siyu , Zhang Mengshao , He Yangjian , Lin Li 
Published: May 2022

AbstractCap-shaped skeletal fossils are the earliest undisputed body fossils of mollusks appearing in the basal Cambrian. A study on the morphometry of cap-shaped fossils from the Nanjiang area (North Sichuan, China) is undertaken to understand the origin and evolution of the early mollusks. The distribution of these fossil cap-shaped mollusks indicates a stepwise increase in their diversity during the early Cambrian.MaikhanellaZhegallo in Voronin et al., 1982 co-occuring with the spinose sclerites of siphogonuchitids, is regarded as the earliest scleritized mollusk. It is followed by other maikhanellids, e.g.,PurellaMissarzhevsky, 1974 andYunnanopleuraYu, 1987, which co-occur with the earliest univalved helcionellids, e.g.,IgorellaMissarzhevsky in Rozanov et al., 1969. Cluster analysis of their morphometric characteristics shows that theMaikhanellagroup is similar to thePurellaandYunnanopleuragroups, but is less comparable with univalved helcionellids. The maikhanellids are interpreted as representatives of the stem group Aculifera, although it remains uncertain if one or two larger cap-shaped shell plates were present on the elongate slug-like body, comparable to those ofHalkieriaPoulsen, 1967 orOrthrozanclusConway Morris and Caron, 2007. Maikhanellids are characterized by the prominent protrusions or scales on the cap-shaped shell plates arranged in a concentric pattern around the shell apex. Evolutionarily, the protrusions or scales are reduced in younger strata, whereas subsequently a typically concentric ornament developed, the cap-shaped shell plates developed higher profiles, and the apical region became increasingly bare of scales. Meanwhile, the cap-shaped shell plates gradually evolved into a helcionellid-like appearance with an anteroposteriorly inclined apex. The morphological evolution of the earliest sclerotized mollusks reflects biotic evolution and environmental adaption among the stem-group mollusks during the early Cambrian.
Citellinema (Nematoda: Heligmosomidae) from North America with descriptions of 2 new species from the red squirrel Tamiasciurus hudsonicus and 1 from the Canadian woodchuck, Marmota monax
Authors: Alnaqeb Haitham , Galbreath Kurt E. , Koehler Anson V. , Campbell Mariel L. , Jiménez F. Agustín 
Published: May 2022

AbstractCitellinema Hall, 1918 includes 6 valid species of gastrointestinal nematodes of sciurids. Two species occur in the Palearctic and 4 in the Nearctic, 3 of which occur minimally across Colorado, Idaho and Oregon and 1, Citellinema bifurcatum, has a wide distribution across North America. Members of the genus are didelphic, possess a cephalic vesicle, a terminal spine-like process in females and feature robust spicules, consisting of a proximal end fused and semicylindrical shaft connected to a lamina supported by 2 terminal filiform processes. Typically, the size of the spicules is used to differentiate species. As part of the Beringian Coevolution Project, specimens provisionally identified as C. bifurcatum were collected through intensive field sampling of mammals and associated parasites from across localities spanning the Holarctic. These specimens revealed considerable genetic variability at both mitochondrial and nuclear loci, supporting the identification of deeply divergent clades. Examination of these new specimens, along with the holotypes of C. bifurcatum and Citellinema quadrivittati indicates that Citellinema monacis (previously synonymized with C. bifurcatum) should be resurrected and 3 additional species described. We suggest that the apparent bifurcated nature of the spicule should be considered a generic diagnostic trait, while the proportional length of the lamina relative to that of the spicule is used as a specific character. We demonstrate the critical need for continued inventory of often poorly known assemblages of hosts and parasites, contributing to a growing baseline of archival specimens, collections and information that make explorations of faunal structure and diversity possible.
Mapping functional tree regions of the Atlantic Forest: how much is left and opportunities for conservation
Authors: Silva José Luiz Alves , Souza Alexandre F , Vitória Angela Pierre 
Published: May 2022

SummaryMany biomes still lack an overall view of their macro-functional structure (i.e., natural biogeographical regions and zones), including the Atlantic Forest biodiversity hotspot. The effective design of protected areas depends on the spatial identification of units with ecologically distinct content, whether it be floristic, phylogenetic or functional. This study used a regionalization approach to identify the potential functional regions of the Atlantic Forest by interpolating functional data from forest remnants into the entire original occurrence area of the biome, including deforested lands. Conservation status was then estimated. Analysis of seven traits of leaf, wood, seed and plant size revealed that the biome is structured over 14 functional regions and three zones (clusters of regions). Functional regions represented specific combinations of traits rather than being characterized by extremely high or low values of a single trait. They retained an average of 29.5% of forest remnants (range: 7.63–54.66%) and 10.82% of protected areas (range: 0.35–35.78%). By analysing the functional space occupied by all regions, captured by two principal component analysis axes using the pixel-level information contained in interpolated trait maps, we showed that large parts of this space were not covered by forest remnants or protected areas and that the most represented regions had serious deficits in protected areas. Although the Serra do Mar mountain range in the south and south-east Atlantic Forest is relevant as a centre of species endemism and richness and has received considerable attention for carrying out ecological studies and creating protection areas, this range does not fully encompass the functional biodiversity of such a rich biome. Our results demonstrate the potential for combining regionalization and conservation approaches to unravel the macro-structures of biomes.
Individual and family predictors of ultra-processed food consumption in Spanish children: The SENDO project
Authors: García-Blanco Lorena , de la O Pascual Víctor , Berasaluce Arantxa , Moreno-Galarraga Laura , Martínez-González Miguel Ángel , Martín-Calvo Nerea 
Published: May 2022

AbstractBackground:Ultra-processed food (UPF) consumption is increasing exponentially, becoming a matter of concern for Public Health, given its adverse health effects.Objective:To identify individual and faGmily factors predicting UPF consumption in childhood.Design:The SENDO project is an ongoing prospective dynamic cohort of Spanish children. In this study, we used baseline information of participants recruited between January 2015 and June 2021. Dietary information was collected with a validated semi-quantitative FFQ, and food items were classified using the NOVA classification. Individual and family factors associated with UPF consumption (P< 0·20) in univariate analyses were introduced in a model of generalised estimating equations which accounted for intra-cluster correlations between siblings.Setting:The SENDO project (Spain), 2015–2021.Participants:Spanish children are recruited at the age of 4–5 years and followed yearly through online questionnaires completed by parents.Results:In this sample of 806 participants (49 % girls; mean age 5 years (sd: 0·90)), the mean UPF consumption was 37·64 % of total energy intake (sd: 9·59). Large family size and longer exposure to screens predicted higher consumption of UPF. On the other hand, better knowledge of children’s dietary recommendations, healthy dietary attitudes towards child’s eating habits and longer breastfeeding were associated with lower consumption of UPF. All these factors accounted for approximately 16 % of the variability on the consumption of UPF in childhood.Conclusion:Since most of the factors identified in this study are modifiable, they should be considered in public health strategies aimed at promoting healthy dietary habits in early life.
Fraud in Online Surveys: Evidence from a Nonprobability, Subpopulation Sample
Authors: Bell Andrew M. , Gift Thomas 
Published: May 2022

AbstractWe hired a well-known market research firm whose surveys have been published in leading political science journals, including JEPS. Based on a set of rigorous “screeners,” we detected what appears to be exceedingly high rates of identity falsification: over 81 percent of respondents seemed to misrepresent their credentials to gain access to the survey and earn compensation. Similarly high rates of presumptive character falsification were present in panels from multiple sub-vendors procured by the firm. Moreover, we found additional, serious irregularities embedded in the data, including evidence of respondents using deliberate strategies to detect and circumvent one of our screeners, as well as pervasive, observable patterns reflecting that the survey had been taken repeatedly by a respondent or collection of respondents. This evidence offers reasons to be concerned about the quality of online nonprobability, subpopulation samples, and calls for further, systematic research.
Large Methane Emission Fluxes Observed From Tropical Wetlands in Zambia
Authors: Shaw Jacob T. , Allen Grant , Barker Patrick , Pitt Joseph R. , Pasternak Dominika , Bauguitte Stéphane J.‐B. , Lee James , Bower Keith N. , Daly Michael C. , Lunt Mark F. , Ganesan Anita L. , Vaughan Adam R. , Chibesakunda Francis , Lambakasa Musa , Fisher Rebecca E. , France James L. , Lowry David , Palmer Paul I. , Metzger Stefan , Parker Robert J. , Gedney Nicola , Bateson Prudence , Cain Michelle , Lorente Alba , Borsdorff Tobias , Nisbet Euan G. 
Published: May 2022

AbstractMethane (CH4) is a potent greenhouse gas with a warming potential 84 times that of carbon dioxide (CO2) over a 20‐year period. Atmospheric CH4 concentrations have been rising since the nineteenth century but the cause of large increases post‐2007 is disputed. Tropical wetlands are thought to account for ∼20% of global CH4 emissions, but African tropical wetlands are understudied and their contribution is uncertain. In this work, we use the first airborne measurements of CH4 sampled over three wetland areas in Zambia to derive emission fluxes. Three independent approaches to flux quantification from airborne measurements were used: Airborne mass balance, airborne eddy‐covariance, and an atmospheric inversion. Measured emissions (ranging from 5 to 28 mg m−2 hr−1) were found to be an order of magnitude greater than those simulated by land surface models (ranging from 0.6 to 3.9 mg m−2 hr−1), suggesting much greater emissions from tropical wetlands than currently accounted for. The prevalence of such underestimated CH4 sources may necessitate additional reductions in anthropogenic greenhouse gas emissions to keep global warming below a threshold of 2°C above preindustrial levels.
Biogeochemical Distinctiveness of Peatland Ponds, Thermokarst Waterbodies, and Lakes
Authors: Arsenault Julien , Talbot Julie , Brown Lee E. , Holden Joseph , Martinez‐Cruz Karla , Sepulveda‐Jauregui Armando , Swindles Graeme T. , Wauthy Maxime , Lapierre Jean‐François 
Published: May 2022

AbstractSmall lentic freshwater ecosystems play a disproportionate role in global biogeochemical cycles by processing large amounts of carbon (C), nitrogen (N), and phosphorus (P), but it is unlikely that they behave as one homogenous group for the purpose of extrapolation. Here, we synthesize biogeochemical data from >12,000 geographically distinct freshwater systems: lakes, peatland ponds, and thermokarst waterbodies. We show that peatland ponds are biogeochemically distinct from the more widely studied lake systems, while thermokarst waterbodies share characteristics with peatland ponds, lakes, or both. For any given size or depth, peatland ponds tend to have dissolved organic carbon concentrations several‐fold higher and are 100‐fold more acidic than lakes because of the organic matter‐rich settings in which they develop. The biogeochemical distinctiveness of freshwater ecosystems highlights the need to account for the fundamental differences in sources and processing of organic matter to understand and predict their role in global biogeochemical cycles.
Subtropical Contribution to Sub‐Antarctic Mode Waters
Authors: Fernández Castro Bieito , Mazloff Matthew , Williams Richard G. , Naveira Garabato Alberto C. 
Published: May 2022

AbstractSub‐Antarctic Mode Waters (SAMW) form to the north of the Antarctic Circumpolar Current (ACC) through deep winter mixing. SAMW connect the atmosphere with the oceanic pycnocline, transferring heat and carbon into the ocean interior and supplying nutrients to the northern ocean basins. The processes controlling SAMW ventilation and properties remain poorly understood. Here, we investigate the significance and origin of a ubiquitous feature of SAMW formation regions: The seasonal build‐up of a subsurface salinity maximum. With biogeochemical Argo floats, we show that this feature influences SAMW mixed‐layer dynamics, and that its formation is associated with a decline in preformed nutrients comparable to biological drawdown in surface waters (∼0.15 mol m−2 y−1). Our analysis reveals that these features are driven by advection of warm, salty, nutrient‐poor waters of subtropical origin along the ACC. This influx represents a leading‐order term in the SAMW physical and biogeochemical budgets, and can impact large‐scale nutrient distributions.
Understanding the Anisotropic Mechanical Behavior of Single‐Crystalline Alpha Quartz From the Insight of Molecular Dynamics
Authors: Molaei Fatemeh 
Published: May 2022

AbstractQuartz is among Earth's most abundant minerals, which has several stable polymorphs in nature. In this study, molecular dynamics simulations are used to investigate the mechanical properties of crystalline alpha quartz. The obtained results specify that tensile stress under uniaxial tension is greater in z (c‐axis) than in other directions (290 vs. 115 GPa and 190 GPa). This outcome confirms that crystalline quartz has an anisotropic behavior under applied load, and as a result, Young's modulus varies in different directions. Furthermore, the effect of existing central cracks with different lengths are considered and the results analyzed. According to the results, central cracks decrease average stress and strain, and this reduction is higher in the z‐direction([0 0 0 1]). Additionally, it was found that the strain rate affects the stress‐strain behavior of the models; however, the strain rate plays a negligible role when the central crack length extends. In terms of potential energy, simulation results indicate that potential energy is the highest in the model without any crack and reduces by growing the central crack size.
The Role of Fault Rock Fabric in the Dynamics of Laboratory Faults
Authors: Pozzi Giacomo , Scuderi Marco M. , Tinti Elisa , Nazzari Manuela , Collettini Cristiano 
Published: May 2022

AbstractFault stability is inherently linked to the frictional and healing properties of fault rocks and associated fabrics. Their complex interaction controls how the stored elastic energy is dissipated, that is, through creep or seismic motion. In this work, we focus on the relevance of fault fabrics in controlling the reactivation and slip behavior of dolomite‐anhydrite analog faults. We designed a set of laboratory experiments where we first develop fault rocks characterized by different grain size reduction and localization at normal stresses of σN = 15, 35, 60, and 100 MPa and second, we reload and reactivate these fault rocks at the frictional stability transition, achieved at σN = 35 MPa by reducing the machine stiffness. If normal stress is lowered this way, reactivation occurs with relatively large stress drops and large peak‐slip velocities. Subsequent unstable behavior produces slow stick‐slip events with low stress drop and with either asymmetric or Gaussian slip velocity function depending on the inherited fault fabric. If normal stress is raised, deformation is accommodated within angular cataclasites promoting stable slip. The integration of microstructural data (showing brittle reworking of preexisting textures) with mechanical data (documenting restrengthening and dilation upon reactivation) suggests that frictional and chemically assisted healing, which is common in natural faults during the interseismic phase, can be a relevant process in developing large instabilities. We also conclude that fault rock heterogeneity (fault fabric) modulates the slip velocity function and thus the dynamics of repeating stick‐slip cycles.
Terrestrial Gamma‐Ray Flashes With Accompanying Elves Detected by ASIM
Authors: Bjørge‐Engeland Ingrid , Østgaard Nikolai , Mezentsev Andrey , Skeie Chris Alexander , Sarria David , Lapierre Jeff , Lindanger Anders , Neubert Torsten , Marisaldi Martino , Lehtinen Nikolai , Chanrion Olivier , Ullaland Kjetil , Yang Shiming , Genov Georgi , Christiansen Freddy , Reglero Victor 
Published: May 2022

AbstractThe Atmosphere‐Space Interactions Monitor was designed to monitor Terrestrial Gamma‐ray Flashes (TGFs) and Transient Luminous Events (TLEs) from space, enabling the study of how these phenomena are related. In this paper, we present observations of 17 TGFs with accompanying Elves. TGFs are short and highly energetic bursts of gamma photons associated with lightning discharges, whereas Elves are TLEs that are observed as concentric rings of ultraviolet (UV) and visible light at ionospheric altitudes, produced by the excitation of N2 molecules when an electromagnetic pulse hits the base of the ionosphere. Elves were identified when optical detections in the UV band could be clearly distinguished from other optical signals from lightning strokes. The TGFs they accompanied had short durations and were associated with particularly high peak current lightning. Lightning sferics associated with these events were detected by the global lightning network GLD360 and the World Wide Lightning Location Network, and they were, with the exception of one event, observed over ocean or coastal regions. It is likely that these events were associated with Energetic In‐cloud Pulses. We show that short duration TGFs tend to be associated with higher peak currents than long duration TGFs.
Heavy Ion Escape From Martian Wake Enhanced by Magnetic Reconnection
Authors: Wang Lei , Huang Can , Ge Yasong , Du Aimin , Wang Rongsheng , Zhang Tielong , Chen Guo , Fan Jinqiao 
Published: May 2022

AbstractMars is a dry planet with a history of a warm and wet environment. Hydrogen and oxygen continuously escape from the unmagnetized planet. Although the heavy ion escape rate in the wake region is low due to Mars' obstruction, there are reports of events with bursty and enhanced ion escape. Here, we first find the evidence of the Alfvenic dayside‐produced plasma clouds accelerated by magnetic reconnection, which provides an explanation for the wake bursty mass escape by the observations from the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. In the event reported by this study, two types of flux ropes were successively observed in the magnetic reconnection exhaust in the Martian wake. One is generated by the reconnection, while others are produced by dayside boundary instability. The ions convected from the dayside, as well as the local original ions, can both be accelerated to be Alfvenic and expelled in the Martian tail by reconnection. The oxygen escape rate in the reconnection exhaust is estimated to be a quarter of the previous statistical result in the entire wake region.
Seasonal Changes in the Vertical Structure of Ozone in the Martian Lower Atmosphere and Its Relationship to Water Vapor
Authors: Olsen K. S. , Fedorova A. A. , Trokhimovskiy A. , Montmessin F. , Lefèvre F. , Korablev O. , Baggio L. , Forget F. , Millour E. , Bierjon A. , Alday J. , Wilson C. F. , Irwin P. G. J. , Belyaev D. A. , Patrakeev A. , Shakun A. 
Published: May 2022

AbstractThe mid‐infrared channel of the Atmospheric Chemistry Suite (ACS MIR) onboard the ExoMars Trace Gas Orbiter is capable of observing the infrared absorption of ozone (O3) in the atmosphere of Mars. During solar occulations, the 003←000 band (3,000‐3,060 cm−1) is observed with spectral sampling of ∼0.045 cm−1. Around the equinoxes in both hemispheres and over the southern winters, we regularly observe around 200–500 ppbv of O3 below 30 km. The warm southern summers, near perihelion, produce enough atmospheric moisture that O3 is not detectable at all, and observations are rare even at high northern latitudes. During the northern summers, water vapor is restricted to below 10 km, and an O3 layer (100–300 ppbv) is visible between 20 and 30 km. At this same time, the aphelion cloud belt forms, condensing water vapor and allowing O3 to build up between 30 and 40 km. A comparison to vertical profiles of water vapor and temperature in each season reveals that water vapor abundance is controlled by atmospheric temperature, and H2O and O3 are anti‐correlated as expected. When the atmosphere cools, over time or over altitude, water vapor condenses (observed as a reduction in its mixing ratio) and the production of odd hydrogen species is reduced, which allows O3 to build up. Conversely, warmer temperatures lead to water vapor enhancements and ozone loss. The LMD Mars Global Climate Model is able to reproduce vertical structure and seasonal changes of temperature, H2O, and O3 that we observe. However, the observed O3 abundance is larger by factors between 2 and 6, indicating important differences in the rate of odd‐hydrogen photochemistry.
Source Identification and Estimation of Organic Carbon in the Intertidal Wetlands of the Eastern Coast of China
Authors: Ding Yan , Wang Dongqi , Chen Shu , Deng Huanguang , Yu Zhongjie , Liu Lijie , Li Yu , Yang Dong , Gao Yingyuan , Nie Jiaqin , Chen Zhenlou 
Published: May 2022

AbstractIntertidal wetlands are important carbon reservoirs that play a significant role in climate change mitigation. However, the lack of large‐scale quantification and source identification of sediment organic carbon (SOC) in different discharge estuaries hampers the assessment of the carbon storage potential in these systems. In this study, based on the elemental ratios and stable carbon isotopes of the core sediment from the intertidal wetlands along the east coast of China, we quantified the contribution of organic carbon (OC) derived from terrestrial/estuarine particulate organic matter (POM), marine phytoplankton, and local plants, such as mangrove and salt marsh plants in the study area. We explored the hydrological and plant drivers controlling the variation in the contribution of OC sources among different coastal environmental settings. We found that SOC in high discharge estuaries (river runoff more than 50 billion m3/a) originated predominantly from terrestrial/estuarine POM (45 ± 6%), whereas the primary source for low discharge estuaries was marine phytoplankton OC (51 ± 14%). Moreover, our estimates revealed a sharp increase in the contribution of OC from mangroves to deep sediments compared with surface sediments, owing to the infiltration of mangrove roots at greater depths and the slow degradation of roots contributing to the substantial refractory OC buried in the deep sediments. These findings indicate that carbon storage in the intertidal wetlands varies among contrasting coastal environmental conditions, which provides implications for intertidal wetlands as a critical carbon sink in the global carbon budget.