bluuebunny/crossref_metadata_2025 huggingface dataset:
Paleontology and ichnology of the late Ediacaran Nasep–Huns transition (Nama Group, southern Namibia)
Authors: Turk Katherine A. , Maloney Katie M. , Laflamme Marc , Darroch Simon A.F.
Published: May 2022

The Nasep and Huns members of the Urusis Formation (Nama Group), southern Namibia, preserve some of the most diverse trace-fossil assemblages known from the latest Ediacaran worldwide, including potentially the world's oldest “complex” vertical sediment-penetrating burrows. These sediments record relatively diverse communities of bilaterian metazoans existing before the base of the Cambrian and an increase in the intensity of metazoan ecosystem engineering behaviors that could eventually produce profound changes in the character of the Phanerozoic sedimentary record (the “agronomic revolution”). Despite this, relatively little about this trace-fossil assemblage is known. We explore the Nasep–Huns transition at two localities in the Witputs sub-basin and describe the trace- and body-fossil diversity present in these horizons alongside a paleoenvironmental reconstruction. We document eight unique ichnotaxa from these localities, including well-preserved “probes” potentially left by priapulids. We also report the first occurrence ofCorumbellafrom Namibia, helping to establish a biostratigraphic link between Namibia, Brazil, Paraguay, Iran, and the southwestern United States. Last, we find that several ichnotaxa, in particular small treptichnids, appear to be preferentially preserved on the bases of gutter casts, hinting at the potential existence of an unusual late Ediacaran preservational window with possible implications for timing the first appearance of key bilaterian behaviors.
Unpacking the Impact of OFDI Speed and Rhythm on Innovation Performance: Evidence from Chinese Firms
Authors: Wu Xiaobo , Du Jian , Xu Yue , Xu Hongqi , Zhu Shan
Published: May 2022

In this study, we focus on the temporal behaviors – speed and rhythm – of outward foreign direct investment (OFDI) by emerging multinational enterprises (EMNEs) and examine the effect of such behaviors on innovation performance. Using a learning perspective, we argue that OFDI speed has an inverted U-shaped effect on EMNEs’ innovation performance, whereas the relationship between the uneven rhythm of OFDI and innovation performance is negative. The results, based on OFDI panel data of 1,092 Chinese firms, support our predictions that a moderate OFDI speed and a more regular pattern of OFDI expansion provide sources of competitiveness and contribute to firms’ innovation performance.
Achieving Mutual Understanding Without Saying a Word: The Conceptualization of Moqi and a Nomological Network
Authors: Chen Xiao-Ping , Cole Benjamin M.
Published: May 2022

While the construct of moqi (默契, pronounced ‘mò-chee’) is ubiquitously understood and finds itself in everyday conversations around the home and workplace in China, the theoretical development of moqi has been scarce. In this article, we expand on prior work on moqi and conceptualize moqi as a dyadic level construct that describes a situated state of shared contextualized understanding without saying a word between two counterparties. We further articulate a broader view of moqi as a dyadic communication construct that is both target-specific and situation-specific. We propose a nomological network of moqi that shows how shared contextualized understandings between counterparties are informed by several different layers, including ‘capability’ (a) a generalized proclivity to be able to form such understandings with others, and ‘contributing factors’, (b) how those understandings are formed either (i) through interactions or (ii) without them through overlaps in background characteristics or experiences, and (c) how other factors accentuate the capability and inclination to ultimately achieve moqi. We then discuss several potential consequences of moqi in organizational settings. Finally, we discuss why moqi is a powerful form of effective communication that is meaningful beyond the Chinese cultural context.
How Are Politicians Informed? Witnesses and Information Provision in Congress
Authors: BAN PAMELA , PARK JU YEON , YOU HYE YOUNG
Published: May 2022

How are politicians informed and who do politicians seek information from? The role of information has been at the center for research on legislative organizations but there is a lack of systematic empirical work on the information that Congress seeks to acquire and consider. To examine the information flow between Congress and external groups, we construct the most comprehensive dataset to date on 74,082 congressional committee hearings and 755,540 witnesses spanning 1960–2018. We show descriptive patterns of how witness composition varies across time and committee and how different types of witnesses provide varying levels of analytical information. We develop theoretical expectations for why committees may invite different types of witnesses based on committee intent, interbranch relations, and congressional capacity. Our empirical evidence shows how committees’ partisan considerations can affect how much committees turn to outsiders for information and from whom they seek information.
Flood basalt structures and textures as guides to cooling histories and palaeoclimates: the Deccan Traps of Saurashtra, western India
Authors: Sheth Hetu , Duraiswami Raymond A. , Ghule Vivek , Naik Anmol , Das Tarulata
Published: May 2022

The primary features (morphologies, structures, textures) of volcanic lava flows are determined by parameters such as composition, temperature, crystallinity, viscosity, flow velocity, strain rate and cooling rate. However, lava flows are open systems, and their primary features are strongly influenced by their emplacement environment. Among subaerial lava flows, those that solidify in a wet environment with rainfall develop very different internal structures (e.g. jointing patterns) and textures from those in a dry environment. Thus, the outcrop structures and textures of ancient lava flows, such as those forming continental flood basalt sequences thousands of metres thick, provide clues to their cooling histories and the palaeoclimates. Here we provide field, petrographic and geochemical data on large tholeiitic lava flows (sheet lobes) and associated dykes of the Saurashtra region in the northwestern Deccan Traps continental flood basalt province (India). The sheet lobes are dominantly pāhoehoe and rubbly pāhoehoe, and occasionally ‘a‘ā, with colonnade and entablature tiers. We show that the jointing patterns in the entablatures (irregular, chevron, rosette and skeleton jointing), and the textures of the sheet lobes and even some dykes (abundant glass, and quench crystals of plagioclase and Fe–Ti oxides) reflect convective heat removal, owing to widespread interaction with meteoric waters (rainfall) during solidification. The observations thus provide evidence for a wet climate in western India 65.5 million years ago.
Palatalisation can be quantity-sensitive: Dorsal Fricative Assimilation in Liverpool English
Authors: CARDOSO AMANDA , HONEYBONE PATRICK
Published: May 2022

This paper shows that the Liverpool English dorsal fricative, derived through the lenition of /k/, is subject to place of articulation assimilation, driven by the preceding vowel. This is similar to the vowel-driven aspects of typical perseverative Dorsal Fricative Assimilation (a type of palatalisation), as found, for example, in the Germanich-Laut~ach-Lautalternation, where (among other things) a preceding front high or mid vowel is followed by the front dorsal [ç], and other vowels are followed by a back dorsal. However, the majority Liverpool English pattern differs from previously described cases of Dorsal Fricative Assimilation in that [ç] only occurs followinglongfront high vowels, while a back dorsal remains after their short congeners. This type of quantity-sensitive pattern in assimilation has not been reported before. We use Centre of Gravity measurements to investigate this pattern of place assimilation, and argue for the use of an innovative normalisation technique for consonant measurements, based on measurements of /k/ aspiration in a linear regression model. We thus both expand the taxonomy of what is known to be possible in phonology and also provide new detail in the description of Liverpool English (including a proposal for the featural analysis of its vowel system).
Similarities and differences among the Opisthorchiidae liver flukes: insights from Opisthorchis felineus
Authors: Pakharukova Maria Y. , Mordvinov Viatcheslav A.
Published: May 2022

The foodborne liver trematode Opisthorchis felineus (Rivolta, 1884) is a member of the triad of phylogenetically related epidemiologically important Opisthorchiidae trematodes, which also includes O. viverrini (Poirier, 1886) and Clonorchis sinensis (Loos, 1907). Despite similarity in the life cycle, Opisthorchiidae liver flukes also have marked differences. Two species (O. viverrini and C. sinensis) are recognized as Group 1A biological carcinogens, whereas O. felineus belongs to Group 3A. In this review, we focus on these questions: Are there actual differences in carcinogenicity among these 3 liver fluke species? Is there an explanation for these differences? We provide a recent update of our knowledge on the liver fluke O. felineus and highlight its differences from O. viverrini and C. sinensis. In particular, we concentrate on differences in the climate of endemic areas, characteristics of the life cycle, the range of intermediate hosts, genomic and transcriptomic features of the pathogens, and clinical symptoms and morbidity of the infections in humans. The discussion of these questions can stimulate new developments in comparative studies on the pathogenicity of liver flukes and should help to identify species-specific features of opisthorchiasis and clonorchiasis pathogenesis.
The timing and development of infections in a fish–cestode host–parasite system
Authors: Wohlleben Anika M. , Steinel Natalie C. , Meyer Néva P. , Baker John A. , Foster Susan A.
Published: May 2022

The cestode Schistocephalus solidus is a common parasite in freshwater threespine stickleback populations, imposing strong fitness costs on their hosts. Given this, it is surprising how little is known about the timing and development of infections in natural stickleback populations. Previous work showed that young-of-year stickleback can get infected shortly after hatching. We extended this observation by comparing infection prevalence of young-of-year stickleback from 3 Alaskan populations (Walby, Cornelius and Wolf lakes) over 2 successive cohorts (2018/19 and 2019/20). We observed strong variation between sampling years (2018 vs 2019 vs 2020), stickleback age groups (young-of-year vs 1-year-old) and sampling populations.
Prevalence and phylogeography of Taenia hydatigena metacestodes from goats of India
Authors: Moudgil Aman D. , Nehra Anil K. , Vohra Sukhdeep , Thakur Sidharath Dev , Sharma Dinesh
Published: May 2022

The study determined the prevalence and genetic population structure relationships of Cysticercus tenuicollis (Taenia hydatigena metacestode) retrieved from the goats slaughtered in north India. An overall prevalence of 9.62% (59/613) was recorded. Genetic population structure relationships were assessed by targeting partial cytochrome c oxidase subunit 1 mitochondrial gene sequence. Phylogenetic tree analysis revealed that all the present study representative isolates (n = 7) formed a major clade and grouped with T. hydatigena isolates retrieved from sheep, goats, pigs and dogs, originating from China, Iran, Nigeria, Ghana and Poland. However, a single isolate from Himachal Pradesh (isolate 3) formed a subgroup within the clade. The neutrality and diversity indices revealed high values of haplotype diversity [Hd = 0.99695 (0.95238–1.0000)] and low nucleotide diversity (π = 0.49276), which was indicative of demographic expansion and low gene flow, suggesting that Indian T. hydatigena isolates were not genetically differentiated. Tajima's D (−1.26988) and Fu and Li's D statistics values (−0.74556) were negative, demonstrating deviations from neutrality and both propounded recent population expansion or purifying selection. Results highlighted a low genetic diversity of T. hydatigena metacestodes across the geographical range of north India.
Socioeconomic status and eating disorder prevalence: at the intersections of gender identity, sexual orientation, and race/ethnicity
Authors: Burke Natasha L. , Hazzard Vivienne M. , Schaefer Lauren M. , Simone Melissa , O'Flynn Jennifer L. , Rodgers Rachel F.
Published: May 2022

Background

Longstanding biases have fostered the erroneous notion that only those of higher socioeconomic status (SES) experience eating disorders (EDs); however, EDs present across all SES strata. Considering the dearth of ED research among those of lower SES, this study examined (1) the overall association between SES and ED prevalence, and (2) ED prevalence in the context of four relevant social identities (i.e. SES, gender identity, sexual orientation, and race/ethnicity) from an intersectional perspective, as unique combinations of multiple social identities may differentially influence risk.

Methods

A sample of 120 891 undergraduate/graduate students from the Healthy Minds Study self-reported family SES with a single-item question, gender identity, sexual orientation, and race/ethnicity, and were screened for ED risk.

Results

Participants of lower SES had 1.27 (95% CI 1.25–1.30) times greater prevalence of a positive ED screen than those of higher SES. Substantial heterogeneity was observed across the four social identities beyond the association with SES. For example, positive ED screens were particularly common among lower SES, Latinx, sexual minority cisgender men and women, with 52% of bisexual men and 52% of lesbian women of Latinx ethnicity and lower SES screening positive.

Conclusions

Although positive ED screens were more common among undergraduate/graduate students of lower SES, the particularly high ED risk reported by certain groups of lower SES with multiple minority identities reinforces the importance of investigating multi-layered constructs of identity when identifying groups at disproportionate risk.
Configuration design and experimental verification of a variable constant-force compliant mechanism
Authors: Ding Bingxiao , Li Xuan , Li Yangmin
Published: May 2022

The realizing of variable output constant force has received wide attention. To achieve a force regulation in an economic way, a configuration of the constant force mechanism (CFM) referring to positive and negative stiffness combination method is proposed in this paper. By adjusting preloading displacement applied on positive-stiffness structure of the CFM, the variable constant force output can be realized. The force–displacement expression of the CFM in the non-preloaded condition is deduced by the established analytical models. Furthermore, parametric sensitivity analysis with several architectural parameters are conducted for optimizing physical structures. Finally, the correctness of the proposed principle is verified by experimental studies. The observed experimental results show that the CFM under different preloading displacements can provide required output constant force, which is consistent with proposed hypothesis.
Plant community and native primate as drivers of habitat use by an exotic primate (Saimirispp. Linnaeus, 1758) in an Atlantic Forest fragment
Authors: Araújo Ana Caroline L. , Bezerra Bruna M. , Lima Ingrid M. S. , Oliveira-Silva Liany B. , Campêlo Anielise da C. , Souza-Alves João Pedro
Published: May 2022

Understanding how and why exotic species use their habitats is crucial for defining effective conservation strategies. We aimed to investigate habitat use by an exotic population of squirrel monkeys living in an Atlantic Forest fragment and identify factors associated with their habitat preferences. Over 6 months of scan sampling observations, we collected data on native and exotic plants consumed by the squirrel monkeys, food availability, and interactions between the squirrel monkeys and the native common marmosets. We also georeferenced the estimated centroid point of the study group during each scan. Squirrel monkeys used Secondary Old Forest habitats more often than the other habitats available. The consumption of native and exotic plants and the association with common marmoset appear to have influenced the habitat use of the exotic squirrel monkeys; however, the choice habitat did not demonstrate to be associated with food availability. The exotic squirrel monkeys preferred to use less disturbed habitats to consume a high amount of food (often associated with the common marmoset), potentially optimizing their food intake. Our findings demonstrated the adaptive success of an exotic primate in its non-natural habitat and the key role of the plant community in maintaining this population.
Spatial and taxonomic diversification for conservation investment under uncertainty
Authors: Kang Nawon , Sims Charles , Cho Seong-Hoon
Published: May 2022

Conservation organizations often need to develop risk-diversification strategies that identify not just what species to protect but also where to protect them. The objective of this research is to identify optimal conservation investment allocations for both target sites and species under conditions of uncertainty. We develop a two-step approach using modern portfolio theory (MPT) to estimate percentages of conservation investment (referred to as ‘portfolio weights’) for counties and taxonomic groups in the central and southern Appalachian region under climate and market uncertainties. The portfolio weights across the counties and taxonomic groups from the two steps entail both spatial and taxonomic diversification strategies. Conservation decisions that allow for selecting sites for risk diversification fit the purpose of the first step. Likewise, conservation investments that benefit the biodiversity of particular taxonomic groups for the selected sites are made based on the relative importance of diversifying risk among species in a given area, fitting the purpose of the second step. The two-step MPT approach as a whole allows the greatest flexibility on where and what to protect for conservation investment under uncertainty, and thus would be applicable for the distribution of general conservation funds without predisposition towards protecting either specific sites or species.
Network analysis of England's single parent household COVID-19 control policy impact: a proof-of-concept study
Authors: Edelman N. L. , Simon P. , Cassell J. A. , Kiss I. Z.
Published: May 2022

Lockdowns have been a core infection control measure in many countries during the coronavirus disease 2019 (COVID-19) pandemic. In England's first lockdown, children of single parent households (SPHs) were permitted to move between parental homes. By the second lockdown, SPH support bubbles between households were also permitted, enabling larger within-household networks. We investigated the combined impact of these approaches on household transmission dynamics, to inform policymaking for control and support mechanisms in a respiratory pandemic context. This network modelling study applied percolation theory to a base model of SPHs constructed using population survey estimates of SPH family size. To explore putative impact, varying estimates were applied regarding extent of bubbling and proportion of different-parentage within SPHs (DSPHs) (in which children do not share both the same parents). Results indicate that the formation of giant components (in which COVID-19 household transmission accelerates) are more contingent on DSPHs than on formation of bubbles between SPHs, and that bubbling with another SPH will accelerate giant component formation where one or both are DSPHs. Public health guidance should include supportive measures that mitigate the increased transmission risk afforded by support bubbling among DSPHs. Future network, mathematical and epidemiological studies should examine both independent and combined impact of policies.
Apocalyptic belief and prophecy: constructing political legitimacy during the Yuan-Ming transition
Authors: Liu Haiwei
Published: May 2022

According to recent research, after the Song dynasty, there was a transformation of the political culture in imperial China according to which Confucian elites and dynastic rulers ceased to construct political legitimacy by interpreting prophecies. By examining the process of how Zhu Yuanzhang, the founder of the Ming dynasty, utilized a popular prophecy and how he concealed his utilization of this prophecy after enthronement, this article offers a more nuanced narrative of the transformation. It shows that during the Yuan-Ming transition, rulers sought to employ prophecies to construct their image as sovereigns favoured by Heaven, but, ironically, in official writings rulers tended to hide their utilization of prophecies so as to highlight their virtues which deserved the Mandate of Heaven. This article argues that after the Song, the role of prophecies changed in the political arena—not from important to unimportant, but from officially recognized to officially concealed.
The role of socioemotional wellbeing difficulties and adversity in the L2 acquisition of first-generation refugee children
Authors: Paradis Johanne , Soto-Corominas Adriana , Vitoroulis Irene , Al Janaideh Redab , Chen Xi , Gottardo Alexandra , Jenkins Jennifer , Georgiades Katholiki
Published: May 2022

First-generation refugee children often experience pre- and post-migration adversity and display high levels of mental health/wellbeing difficulties, but to date, research has not examined the impact of such factors on refugee children's L2 acquisition. Accordingly, this study examined the influence of externalizing and internalizing problem behaviours (wellbeing), time in refugee camps and low socioeconomic status (SES) (adversity) on the English-L2 abilities of 117 Syrian refugee children (7–14 years) in their third year of residency in Canada. Wellbeing difficulties and adversity factors accounted for variance on L2 vocabulary, morphosyntax, listening comprehension and narrative production tasks, beyond the variance accounted for by age of L2 acquisition and length of L2 exposure. Specifically, externalizing problem behaviours, time in refugee camp, maternal education and maternal employment predicted variance in L2 abilities. It is concluded that refugee children could have influences on their L2 acquisition that are different from those of bilinguals with other backgrounds.
Dynamic engagement of cognitive control in intra-sentential code-switching during comprehension
Authors: Jiang Siyi , Ma Lvheng , Chen Baoguo
Published: May 2022

This study investigated whether the deployment of cognitive control was modulated by the intra-sentential code-switching types during comprehension. L1-dominant Chinese–English bilinguals were administered a self-paced reading task in two reading contexts – namely, alternation context and dense code-switching context. We assessed language switch cost and reversed language dominance effect in the self-paced reading task and examined how these language control measures related to domain-general inhibition and monitoring capacities. The results showed a larger switch cost asymmetry in alternation context compared to dense CS context. In addition, bilinguals’ inhibition skills were associated with second language (L2) switch cost in alternation context, while monitoring tended to predict the language dominance effect in dense code-switching context. These findings suggest that alternation context exerts high requirement to reactive inhibition while dense code-switching context tends to induce proactive monitoring during comprehension. We conclude that intra-sentential code-switching types trigger different aspects of cognitive control during comprehension.
“A Very Crushable, Kissable Girl”: Queer Love and the Invention of the Abnormal Girl Among College Women in the Gilded Age and Progressive Era
Authors: Rouse Wendy L.
Published: May 2022

Young women growing up in the Gilded Age and Progressive Era increasingly found their relationships subject to scrutiny as doctors, parents, teachers, and school administrators began to worry about the so-called abnormal girl. Attempts to suppress the culture of crushes and romantic friendships between young women reflected these larger cultural anxieties about their relationships. But, as notions of normative girlhood began to form, this intense scrutiny of their relationships had a significant impact on their everyday lives. The young women who were navigating this scientific and cultural shift developed a range of innovative strategies from subversively concealing their relationships to boldly pursuing their queer desires.
Pax populi? An analysis of the conflict resolution potential of referendums on self-determination
Authors: Germann Micha
Published: May 2022

The international community increasingly promotes referendums as it intervenes in self-determination conflicts around the world. However, the ability of self-determination referendums to bring about peace remains uncertain. This paper develops the argument that the conflict resolution potential of self-determination referendums is conditional, depending on whether or not they are held under the mutual agreement of the relevant minority and majority groups. When mutually agreed, self-determination referendums are likely to generate shared perceptions of fair decision-making and thereby increase chances for peace. By contrast, unilateral self-determination referendums are likely to increase ethnic grievances and, therefore, the risk of separatist violence. I find support for this argument in a global statistical analysis, short case studies, and a survey experiment. Overall, this study suggests that self-determination referendums can make a positive contribution to peace, but only if the conditions for a partial compromise on a referendum, including its terms, are ripe.
Proliferation of International Administrative Tribunals
Authors: DE COOKER Chris
Published: May 2022

The first international administrative tribunal was set up in 1927. Since the Second World War many worldwide and regional international organizations were set up. They either created their own tribunal or accepted the jurisdiction of another tribunal for the adjudication of employment disputes. Dozens of such tribunals are functioning at present. Recently a number of organizations have withdrawn from the Administrative Tribunal of the International Labour Organization (ILOAT), and either set up their own tribunal or accepted the jurisdiction of another tribunal, which amounts to forum shopping. However, the proliferation of tribunals entails the risk of diverging judgments. Some cases have indeed occurred over the years, which have often been followed by calls for the merging of tribunals, or for the creation of a common appellate court. Some studies were made, but no concrete action was ever undertaken. Generally, there has been some convergence; however, it is likely that the current proliferation will remain.
New Data on Court Curbing by State Legislatures
Authors: Leonard Meghan E.
Published: May 2022

The examination of the interaction between the institutions in American state politics has long suffered from a dearth of data. This is the case despite the importance of understanding the separation of powers in the states and the specific effects on policy making and policy outcomes. In this article, I introduce a new, original dataset of court-curbing introductions by state legislators. The data include information on more than 1,200 state legislative bills that would restrict the power of the courts. In this article, I provide descriptive statistics for the data, employ the data to test hypotheses, and explain how this data may be used in future scholarly research on the interactions between state legislators and state courts.
The Effect of Grain Size on Porewater Radiolysis
Authors: DeWitt J. , McMahon S. , Parnell J.
Published: May 2022

The radiolysis of porewaters by uranium, thorium, and potassium in mineral grains is a recognized source of molecular hydrogen in rock‐hosted and sediment‐hosted fluids. This radiolytic hydrogen is of geomicrobiological interest as a potential energy source (electron donor) for microbial metabolism, especially in energy‐limited settings such as the marine deep biosphere or the subsurface of Mars. Previous efforts to predict the production of radiolytic hydrogen from columns of rock and sediment have tended to rely upon analytic models that cannot account for the attenuation of mineral radiation by grains larger than ∼30 µm. To address this, we have developed a Monte Carlo method to simulate the physics of mineral radiation and evaluate the production of H2 as a function of mineral grain size and radioisotope composition. The results confirm that grain size is a major control on radiolytic H2 yield. For example, using the standard geological classification of grain sizes, we find that clay can produce up to an order of magnitude more H2 per unit time than sand. The magnitude of this effect is illustrated using compositional data from real geological units in order to demonstrate the dependence of radiolytic hydrogen flux on natural radionuclide concentration and bulk porosity.
Projected ENSO Teleconnection Changes in CMIP6
Authors: McGregor Shayne , Cassou Christophe , Kosaka Yu , Phillips Adam S.
Published: May 2022

The El Nino–Southern Oscillation (ENSO) has far reaching impacts through atmospheric teleconnections, which make it a prominent driver of global interannual climate variability. As such, whether and how these teleconnections may change due to projected future climate change remains is a topic of high societal relevance. Here, ENSO Surface Temperature (TAS) and Precipitation (PR) teleconnections between the historical and high‐emission future simulations are compared in more than 31 models from Phase 6 of the Coupled Model Intercomparison Project. We find significant future (2081–2100) TAS and PR teleconnection changes over approximately 50% of teleconnected regions in December‐February relative to 1950–2014. The large majority of these significant teleconnection changes suggest that an amplification of the historical teleconnections will occur, however, some regions also display a significant teleconnection dampening. Further to this, in many regions these ENSO teleconnection changes scale with the projected warming level, with higher warming leading to larger teleconnection changes.
The Influence of Localized Dynamics on Dusk‐Dawn Convection in the Earth’s Magnetotail
Authors: Lane J. H. , Grocott A. , Case N. A.
Published: May 2022

Previous work has shown that earthward convective flow bursts in the magnetotail have a dusk‐dawn () component that is controlled by the historical state of the Interplanetary Magnetic Field (IMF) By component. Here, we analyze 27 years of Cluster, THEMIS and Geotail plasma and magnetic field data and identify 1,639 magnetotail fast flow “detections” that demonstrate a dusk‐dawn asymmetry. We find that ∼70% has a dusk‐dawn direction consistent with that expected from the penetration of IMF By. Superposed epoch analysis suggests that the inconsistency of the remaining ∼30% is not due to a lack of the expected IMF By penetration. Instead, we find that on average, the expected sense of IMF By penetration is associated with flows irrespective of whether those flows agree or disagree with the expected dusk‐dawn asymmetry. IMF By, and the penetrated By do, however, tend to be stronger for “agree” flows. Detections which agree (disagree) tend to be accompanied by a localized perturbation to the By component of the magnetotail magnetic field in the same sign as (opposite to) the prevailing IMF By conditions, which temporarily enhances (overrides) the penetrated field. Agree (disagree) flows also appear to be observed further away from (closer to) the neutral sheet (Bx = 0) and are associated with weaker (stronger) magnetic field dipolarization. Finally, we find that the slower “background” convective flow has an average direction which is consistent with penetration of the expected IMF By, regardless of whether the fast flow itself agrees or disagrees.
Dependence of Nonlinear Effects on Whistler‐Mode Wave Bandwidth and Amplitude: A Perspective From Diffusion Coefficients
Authors: Gan L. , Li W. , Ma Q. , Artemyev A. V. , Albert J. M.
Published: May 2022

The electron resonant interaction with whistler‐mode waves is characterized by transport in pitch angle–energy space. We calculate electron diffusion and advection coefficients (a simplified characterization of transport) for a large range of electron pitch angle and energy using test particle simulations. Nonlinear effects are analyzed by comparing the diffusion coefficients using test particle simulations and quasilinear theory, and by evaluating the advection rates. Dependence of nonlinear effects on the wave amplitude and bandwidth of whistler‐mode waves is evaluated by running test particle simulations with a broad range of wave amplitude and bandwidth. The maximum amplitudes where the quasilinear approach is valid are found to increase with increasing bandwidth, from 50 pT for narrowband waves to 300 pT for broadband waves at L‐shell of 6. Moreover, interactions between intense whistler‐mode waves and small pitch angle electrons lead to large positive advection, which limits the applicability of diffusion‐based models. This study demonstrates the parameter range of the applicability of quasilinear theory and diffusion model for different wave amplitudes and frequency bandwidths of whistler‐mode waves, which is critical for evaluating the effects of whistler‐mode waves on energetic electrons in the Earth’s magnetosphere.
The Drivers of the Martian Bow Shock Location: A Statistical Analysis of Mars Atmosphere and Volatile EvolutioN and Mars Express Observations
Authors: Garnier P. , Jacquey C. , Gendre X. , Génot V. , Mazelle C. , Fang X. , Gruesbeck J. R. , Sánchez‐Cano B. , Halekas J. S.
Published: May 2022

The Martian interaction with the solar wind leads to the formation of a bow shock upstream of the planet. The shock dynamics appear complex, due to the combined influence of external and internal drivers. The extreme ultraviolet fluxes and magnetosonic Mach number are known major drivers of the shock location, while the influence of other possible drivers is less constrained or unknown such as crustal magnetic fields, solar wind dynamic pressure, or the Interplanetary Magnetic Field (IMF) intensity, and orientation. In this study, we compare the influence of the main drivers of the Martian shock location, based on several methods and published datasets from Mars Express (MEX) and Mars Atmosphere Volatile EvolutioN (MAVEN) missions. We include here the influence of the crustal fields, extreme ultraviolet fluxes, solar wind dynamic pressure, as well as (for MAVEN, thanks to magnetic field measurements) magnetosonic Mach number and Interplanetary Magnetic Field parameters (intensity and orientation angles). The bias due to the cross‐correlations among the possible drivers is investigated with a partial correlations analysis. Several model selection methods (Akaike Information Criterion and Least Absolute Shrinkage Selection Operator regression) are also used to rank the relative importance of the physical parameters. We conclude that the major drivers of the shock location are extreme ultraviolet fluxes and magnetosonic Mach number, while crustal fields and solar wind dynamic pressure are secondary drivers at a similar level. The IMF orientation also plays a significant role, with larger distances for perpendicular shocks rather than parallel shocks.
Improved Climate Simulation by Using a Double‐Plume Convection Scheme in a Global Model
Authors: Li Xiaohan , Zhang Yi , Peng Xindong , Chu Wenchao , Lin Yanluan , Li Jian
Published: May 2022

Convective parameterization can drastically regulate the mean climate and tropical transient activity of a General circulation model (GCM). In this study, the physics suite of the NCAR Community Atmosphere Model, version 5 (CAM5) was first ported to the Global‐to‐Regional Integrated Forecast System model. Then, the original convective parameterization of CAM5—with a separate representation of deep convection Zhang–Mcfarlane (ZM) and shallow convection University of Washington (UW)—was replaced by a double‐plume (DP) scheme. This DP scheme adopts a quasi‐unified representation of shallow and deep convection within a single framework. Results demonstrate that the new scheme brings about several improvements in the modeled climate. The differences in the trigger and closure assumptions, lateral mixing rate, and cloud model for the deep convection result in systematic regional differences in the simulated precipitation pattern, cloud vertical structure, and the associated radiative forcing. Compared with ZM‐UW, DP reduces the biases in precipitation over the Indian Ocean, ameliorates the “high‐frequency and low‐intensity” problem of tropical precipitation, and leads to an improved representation of tropical variability, including the Madden–Julian Oscillation. Double‐plume reduces low clouds and increases high clouds in the tropics, due to its internal parallel‐split convective processes and smaller cumulus cloud fraction. Discussions related to parametric tuning of convective parameterization are also presented.
The Geophysical Environment of (486958) Arrokoth—A Small Kuiper Belt Object Explored by New Horizons
Authors: Keane James T. , Porter Simon B. , Beyer Ross A. , Umurhan Orkan M. , McKinnon William B. , Moore Jeffrey M. , Spencer John R. , Stern S. Alan , Bierson Carver J. , Binzel Richard P. , Hamilton Douglas P. , Lisse Carey M. , Mao Xiaochen , Protopapa Silvia , Schenk Paul M. , Showalter Mark R. , Stansberry John A. , White Oliver L. , Verbiscer Anne J. , Parker Joel W. , Olkin Catherine B. , Weaver Harold A. , Singer Kelsi N.
Published: May 2022

NASA's New Horizons mission performed the first flyby of a small Kuiper Belt Object (KBO), (486958) Arrokoth on 1 January 2019. The fast flyby revealed a fascinating, flattened, contact binary replete with a variety of unexpected geologic terrains. However, the irregular shape and constraints imposed by the fast flyby makes it a challenge to understand these features. Here we use the latest New Horizons shape models of Arrokoth to investigate its geophysical environment, including its surface slopes, gravity field, and moments of inertia—which are critical context for understanding Arrokoth's formation, evolution, and peculiar geology. We find that Arrokoth's surface features have a complicated relationship to its geophysical environment. For example, bright material tends to be concentrated in geopotential lows (like the neck), consistent with mass wasting—however, this trend is not consistently observed across Arrokoth. Mass wasting may naturally explain some aspects of Arrokoth's geology, but the actual dynamics of material transport may be complicated owing to Arrokoth's unique shape, spin‐rate, and inferred density. While New Horizons's fast and distant flyby precluded directly measuring Arrokoth's mass, we used techniques previously pioneered for comets and asteroids to infer its density. We find that Arrokoth has a low bulk density of ρ = 235 kg/m3 (1σ range: 155–600 kg/m3). This density is low compared to previously explored small bodies, but is comparable to comets, select binary KBOs, and the ring‐moons of Saturn. This low density may be a critical data‐point for understanding the formation of planetesimals at the dawn of the Solar System.
Constraints on the Emplacement of Martian Nakhlite Igneous Rocks and Their Source Volcano From Advanced Micro‐Petrofabric Analysis
Authors: Griffin S. , Daly L. , Keller T. , Piazolo S. , Forman L. V. , Lee M. R. , Baumgartner R. J. , Trimby P. W. , Benedix G. K. , Irving A. J. , Hoefnagels B.
Published: May 2022

The Martian nakhlite meteorites, which represent multiple events that belong to a single magma source region represent a key opportunity to study the evolution of Martian petrogenesis. Here 16 of the 26 identified nakhlite specimens are studied using coupled electron backscatter diffraction (EBSD) and emplacement end‐member calculations. EBSD was used to determine shape preferred orientation of contained augite (high Ca‐clinopyroxene) phenocrysts by considering their crystallographic preferred orientation (CPO). Parameters derived from EBSD, and energy dispersive X‐ray spectroscopy spectra were used in basic emplacement models to assess their dominant mechanism against three end‐member scenarios: thermal diffusion, crystal settling, and crystal convection. Results from CPO analyses indicate low intensity weak‐moderate CPO. In all samples, a consistent foliation within the <001> axes of augite are observed typically coupled with a weaker lineation CPO in one of the other crystallographic axes. These CPO results agree best with crystal settling being the dominant emplacement mechanism for the nakhlites. Modeled crystal settling results identify two distinguishable groups outside of the model's resolution indicating the presence of secondary emplacement mechanisms. Comparison of the two identified groups against CPO, geochemical, and age parameters indicate random variability between individual meteorites. Therefore, coupled CPO and emplacement modeling results identify an overarching characteristic of a dominant crystal settling emplacement mechanism for the nakhlite source volcano despite exhibiting random variation with each discharge through time.
A New Global Ionospheric Electron Density Model Based on Grid Modeling Method
Authors: Le Huijun , Han Tingwei , Li Qiaoling , Liu Libo , Chen Yiding , Zhang Hui
Published: May 2022

Based on nearly 4.6 million radio occultation (RO) ionospheric profile data from Constellation Observing System for Meteorology, Ionosphere, and Climate satellites in 2006–2020, a global three‐dimensional ionospheric electron density model was constructed with a new concept. The global 3D ionosphere structure was divided into total 338,661 grids with longitude intervals of 10°, latitude intervals of 2°, and height intervals of 5 km. On each grid, the electron density is modeled as a function of solar activity, geomagnetic activity, local time, and season variation using 21 coefficients. Then all grid models are combined to form a global ionospheric model. This method makes full use of all ionospheric electron density data. The spatial resolution of the model is high with 10° in longitude, 2° in latitude, and 5 km in height, which can effectively model the fine ionospheric spatial structure like the longitudinal wavenumber‐4 structure in low latitudes. The model also takes into account the influence of both solar and geomagnetic activities on the ionosphere. At the altitude below the F2 peak, the RO electron density observation suffers from an artificial meridional maximum between the double peaks of the equatorial ionization anomaly, referred hereafter as the three‐peak error. By combining our model with the International Reference Ionospheric electron density results of the E layer below 140 km, the problem of three‐peak error is effectively solved. Compared the with other data sources such as the ZH01 and the ROCSAT‐1, the modeling ability of model in fine spatial structure is verified.
An Interactively Corrected Smoothed Particle Hydrodynamics (IC‐SPH) for Simulating Solute Transport in a Nonuniform Velocity Field
Authors: Jiao Tian , Ye Ming , Jin Menggui , Yang Jing
Published: May 2022

The Smoothed Particle Hydrodynamics (SPH) method is a Lagrangian approach that has been widely used to eliminate numerical dispersion for solving advection‐dispersion equation (ADE) of groundwater solute transport under advection‐dominated situations. It has been found that accuracy of SPH results is severely deteriorated, when particles are irregularly distributed in a model domain with heterogeneous hydraulic conductivity. To resolve this problem, we developed a new approach called Interactively Corrected SPH (IC‐SPH), which is an improved version of the Corrected SPH (C‐SPH) method. IC‐SPH uses an interactively corrected kernel gradient to construct concentration gradients used to solve ADE. This correction is made for each particle by using not only the particle's neighbor particles within the particle's support domain but also the particles within each neighbor particle's support domain. We evaluated IC‐SPH performance in two numerical studies. One considers diffusive transport with an analytical solution, and the other considers advection‐dispersion transport in a heterogeneous field of hydraulic conductivity. For each numerical study, several numerical experiments were conducted using multiple sets of irregularly distributed particles with different levels of particle irregularity. The numerical experiments indicate that, while IC‐SPH is more computationally expensive than SPH and C‐SPH, IC‐SPH produces more accurate ADE solutions, and converges faster to the analytical solution. IC‐SPH is mathematically general, and can be applied to a wide range of problems that require solving ADE.
On Infiltration and Infiltration Characteristic Times
Authors: Rahmati Mehdi , Latorre Borja , Moret‐Fernández David , Lassabatere Laurent , Talebian Nima , Miller Dane , Morbidelli Renato , Iovino Massimo , Bagarello Vincenzo , Neyshabouri Mohammad Reza , Zhao Ying , Vanderborght Jan , Weihermüller Lutz , Jaramillo Rafael Angulo , Or Dani , Th. van Genuchten Martinus , Vereecken Harry
Published: May 2022

In his seminal paper on the solution of the infiltration equation, Philip (1969), https://doi.org/10.1016/b978-1-4831-9936-8.50010-6 proposed a gravity time, tgrav, to estimate practical convergence time and the time domain validity of his infinite time series expansion, TSE, for describing the transient state. The parameter tgrav refers to a point in time where infiltration is dominated equally by capillarity and gravity as derived from the first two (dominant) terms of the TSE. Evidence suggests that applicability of the truncated two‐term equation of Philip has a time limit requiring higher‐order TSE terms to better describe the infiltration process for times exceeding that limit. Since the conceptual definition of tgrav is valid regardless of the infiltration model used, we opted to reformulate tgrav using the analytic implicit model proposed by Parlange et al. (1982), https://doi.org/10.1097/00010694-198206000-00001 valid for all times and related TSE. Our derived gravity times ensure a given accuracy of the approximations describing transient states, while also providing insight about the times needed to reach steady state. In addition to the roles of soil sorptivity (S) and the saturated (Ks) and initial (Ki) hydraulic conductivities, we explored the effects of a soil specific shape parameter β, involved in Parlange's model and related to the type of soil, on the behavior of tgrav. We show that the reformulated tgrav (notably where F(β) is a β‐dependent function) is about three times larger than the classical tgrav given by . The differences between the classical tgrav,Philip and the reformulated tgrav increase for fine‐textured soils, attributed to the time needed to attain steady‐state infiltration and thus i + infiltration for inferring soil hydraulic properties. Results show that the proposed tgrav is a better indicator of time domain validity than tgrav,Philip. For the attainment of steady‐state infiltration, the reformulated tgrav is suitable for coarse‐textured soils. Still neither the reformulated tgrav nor the classical tgrav,Philip are suitable for fine‐textured soils for which tgrav is too conservative and tgrav,Philip too short. Using tgrav will improve predictions of the soil hydraulic parameters (particularly Ks) from infiltration data compared to tgrav,Philip.