bluuebunny/crossref_metadata_2025 huggingface dataset:
Cerebrospinal fluid and plasma neurofilament light relate to abnormal cognition
Authors: Osborn Katie E. , Khan Omair A. , Kresge Hailey A. , Bown Corey W. , Liu Dandan , Moore Elizabeth E. , Gifford Katherine A. , Acosta Lealani Mae Y. , Bell Susan P. , Hohman Timothy J. , Blennow Kaj , Zetterberg Henrik , Jefferson Angela L.
Published: October 2019

Introduction

Neuroaxonal damage may contribute to cognitive changes preceding clinical dementia. Accessible biomarkers are critical for detecting such damage.

Methods

Plasma and cerebrospinal fluid (CSF) neurofilament light (NFL) were related to neuropsychological performance among Vanderbilt Memory & Aging Project participants (plasma n = 333, 73 ± 7 years; CSF n = 149, 72 ± 6 years) ranging from normal cognition (NC) to mild cognitive impairment (MCI). Models adjusted for age, sex, race/ethnicity, education, apolipoprotein E ε4 carriership, and Framingham Stroke Risk Profile.

Results

Plasma NFL was related to all domains (P values ≤ .008) except processing speed (P values ≥ .09). CSF NFL was related to memory and language (P values ≤ .04). Interactions with cognitive diagnosis revealed widespread plasma associations, particularly in MCI participants, which were further supported in head‐to‐head comparison models.

Discussion

Plasma and CSF NFL (reflecting neuroaxonal injury) relate to cognition among non‐demented older adults albeit with small to medium effects. Plasma NFL shows particular promise as an accessible biomarker with relevance to cognition in MCI.
“I think the comfort women are us”: National identity and affective historical empathy in students’ understanding of “comfort women” in South Korea
Authors: Jun Hana
Published: October 2019

This study investigates how students’ national identity affects their historical understanding by mediating their use of affective historical empathy. The research focuses on the case of “comfort women” (women forced into sexual slavery for Japanese soldiers during WWII) in South Korea—a topic in which a strong nationalist narrative dominates social and educational discourses. I conducted semi-structured, task-based group interviews with 16 high school students in South Korea. In interviews, students’ national identity mediated how they utilized four types of affective historical empathy: Students as ethnic Koreans cared more about “our” Korean comfort women over others; cared that Korean comfort women and others suffered from what “we” and “they” did as nations; cared for those women's voices from a humanitarian perspective beyond their ethnic and national boundaries; and cared to make social changes for those women and themselves as future citizens of their democratic nation. These findings help us understand how students’ emotional attachment to “our” nation and its members can mediate their historical understanding through affective historical empathy as well as how affective historical empathy can motivate students to move beyond purely nationalistic concerns. This case study also stimulates reflection on historical empathy's implications for students’ democratic civic participation.
Documenting Archaeological Sites on Mountains and Slopes with Drones
Authors: Castillo Luis Jaime , Serván Fabrizio , Patroni Karla
Published: October 2019

The addition of drones to the archaeologist's toolbox has brought about exciting new possibilities, particularly for field research and the conservation and protection of our built heritage. As drones become more widely available and effective, the challenge of precision becomes more important. Better georeferencing and higher-resolution outputs are the current thresholds. In order to achieve the second objective with our current equipment, drones have to fly closer to the ground and, ideally, follow the elevation of the surface. This task can be extremely complicated along the steep surfaces and mountains typical to the Andean region where we work. In this article, we present a recording (flying and photographing) methodology that achieves a higher ground resolution by dividing up the sites into several altitudinal sections, which are flown independently yet processed photogrammetrically as a single set. We have named this methodology “Flying Slopes in Multiple Stepped Polygons.”
Low-boom low-drag solutions through the evaluation of different supersonic business jet concepts
Authors: Sun Y. , Smith H.
Published: October 2019

This paper evaluates six supersonic business jet (SSBJ) concepts in a multidisciplinary design analysis optimisation (MDAO) environment in terms of their aerodynamics and sonic boom intensities. The aerodynamic analysis and sonic boom prediction are investigated by a number of conceptual-level numerical approaches. The panel method PANAIR is integrated to perform automated aerodynamic analysis. The drag coefficient is corrected by the Harris wave drag formula and form factor method. For sonic boom prediction, the near-field pressure is predicted through the Whitham F-function method. The F-function is decomposed to the F-function due to volume and the F-function due to lift to investigate the separate effect on sonic boom. The propagation method for the near-field signature in a stratified windy atmosphere is the waveform parameter method. In this research, using the methods described and publically available data on the concepts, the supersonic drag elements and sonic boom signature due to volume distribution and lift distribution are analysed. Based on the analysis, low-boom and low-drag design principles are identified.
Suspension as Spandrel
Authors: Sosa Ernest
Published: October 2019

A telic virtue epistemology was presupposed in our treatment of insight and understanding. What follows will lay out the main elements of that telic theory and explore how it provides an epistemology of suspension.
Pseudo-outbreak of Mycobacterium chimaera through aerators of hand-washing machines at a hematopoietic stem cell transplantation center
Authors: Nakamura Shingen , Azuma Momoyo , Sato Masami , Fujiwara Noriko , Nishino Saori , Wada Takayuki , Yoshida Shiomi
Published: October 2019

We identified a waterborne pseudo-outbreak of Mycobacterium chimaera in our stem cell transplantation center, which likely resulted from biofilm on the aerators of the handwashing machines in each patient’s room. Regular replacement of faucet parts can prevent biofilm formation and pseudo-outbreaks of M. chimaera through aerators.
Prey fractionation in the Archaeocyatha and its implication for the ecology of the first animal reef systems
Authors: Antcliffe Jonathan B. , Jessop William , Daley Allison C.
Published: October 2019

Archaeocyaths are the most abundant sponges from the Cambrian period, having formed the first animal reef communities more than 500 million years ago. The Archaeocyatha are index fossils for correlating rocks of similar ages globally because of their abundance, extensive geographic distribution, detailed anatomy, and well-established taxonomy. Their ecological significance remains incompletely explored, yet they are known to have strongly competitively interacted, unlike modern sponges. This study examines the feeding ecology of the fossil remains of Siberian archaeocyath assemblages. As suspension feeders, archaeocyaths filtered plankton from the water column through pores in their outer wall. Here we outline a new method to estimate the limit on the upper size of plankton that could be consumed by an archaeocyath during life. The archaeocyaths examined were predominantly feeding on nanoplankton and microplankton such as phytoplankton and protozooplankton. Size-frequency distributions of pore sizes from six different Siberian archaeocyath assemblages, ranging from Tommotian to Botoman in age, reveal significantly different upper limits to the prey consumed at each locality. Some of the assemblages contain specimens that could have fed on larger organisms extending into the mesoplankton, including micro-invertebrates as a possible food resource. These results show that during the establishment of the first animal reef systems, prey partitioning was established as a way of reducing competition. This method has applicability for understanding the construction and the functioning of the first reef systems, as well as helping to understand modern reef systems and their development though time and space.
Variation in ovineKRTAP8-1is associated with variation in wool fibre staple strength and curvature
Authors: Gong H. , Zhou H. , Li W. , Wang J. , Li S. , Luo Y. , Hickford J. G. H.
Published: October 2019

KRTAP8-1was the initial high-glycine-tyrosine keratin-associated protein gene recognized in sheep, but little is known about the functional influence of this gene. The current study used polymerase chain reaction-single stranded conformational polymorphism analysis to genotypeKRTAP8-1in 391 Southdown × Merino-cross sheep from six sire-lines. Five previously described variants (namedAtoE) ofKRTAP8-1were identified with frequencies of 67.0, 14.2, 7.0, 10.7 and 1.0%, respectively. Of the four variants (A,B,CandD) that occurred at a frequency greater than 5%, the presence ofCwas found to be associated with a reduction in mean fibre curvature (MFC) and the presence ofDwas associated with an increase in mean staple strength (MSS), whereas the presence ofAhad a trend of association with reduced MSS. Associations were not identified with other wool traits. These results suggest that variation inKRTAP8-1affects MSS and MFC, and thatKRTAP8-1has the potential to be used as a genetic marker for improving these traits.
On the Expected Earnings Hypothesis Explanation of the Aggregate Returns–Earnings Association Puzzle
Authors: Bailey Warren , Lai Huiwen
Published: October 2019

We provide strong support for the underappreciated expected earnings hypothesis of a negative correlation between aggregate stock returns and earnings. For 1970–2000, our powerful modeling strategy incorporating macroeconomic information reveals that aggregate returns are significantly and negatively correlated with expected aggregate earnings changes but uncorrelated with unexpected aggregate earnings changes. However, this negative correlation changes after 2000, perhaps from heightened volatility or accounting changes. We also show that underlying macroeconomic information explains the power of aggregate earnings to predict future gross domestic product growth.
Punishing the violators? Arms embargoes and economic sanctions as tools of norm enforcement
Authors: Erickson Jennifer L.
Published: October 2019

The persistence and strength of international norms are thought to depend partly on the willingness of actors to punish their violation, but norm enforcement is often inconsistent. This article investigates states’ use of economic sanctions in order to gain insight into the role of metanorms (norms about enforcing norms) in international politics and explain this inconsistency. The quantitative analyses examine patterns of economic sanctions and arms embargo practices across different security norms and reveal two central findings. First, international metanorms may accommodate important interstate relationships. Although severe human rights abuse, conflict, nuclear weapons development, and support for terrorist organisations tend to attract sanctions, they are infrequent in comparison with norm violations. Valued relationships between senders and targets seem to be an accepted limit to the pursuit of costly norm enforcement. Second, norm violations nevertheless remain rare, suggesting that factors other than the prospect of material punishment may encourage compliance. Indeed, by preserving interstate relationships, international metanorms may facilitate the engagement needed for socialisation and social pressures as alternative compliance mechanisms.
Direct electron acceleration with a linearly polarized laser beam in a two-dimensional magnetized plasma channel
Authors: Ghorbanalilu Mohammad , Nozarnejad Nasim
Published: October 2019

We examine the electron acceleration induced by an ultra-relativistic intensity laser–plasma interaction in a two-dimensional plasma channel in the presence of a self-generated transverse magnetic field. We find that the electron dynamics is strongly affected by the laser pulse polarization angle, plasma density, and magnetic field strength. We investigate in detail, the dependencies of the electron acceleration in terms of different parameters and find excellent agreement with non-magnetized plasma in the absence of the magnetic field. The numerical results show that the self-generated magnetic field plays a constructive role in the electron acceleration process. It is shown that electron acceleration is more affected by self-generated magnetic field for the laser radiations with large polarization angles. The numerical results show the maximum enhancement for electron acceleration for a laser radiation with polarization angle θ = π/2.
Gulf Coast Influence at Moxviquil, Chiapas, Mexico
Authors: Paris Elizabeth H. , López Bravo Roberto
Published: October 2019

This article presents evidence for the shifting economic networks and cultural relationships between the Jovel Valley of highland Chiapas, and the Gulf Coast lowlands. In particular, we examine material culture of Gulf Coast origin or influence at the hilltop monumental centre of Moxviquil during the Late Classic (ad600–900) and Early Postclassic (ad900–1250) periods. These artifacts include a fine orange cylindrical pedestal vase, two examples of ‘portable sculpture’, two anthropomorphic incense burner lids and a whistle (ocarina) in the shape of a kneeling woman. The patterns of curation and disposal of these objects at Moxviquil suggests differences in the way that Gulf Coast-referencing objects were incorporated into social memory and ritual behaviour.
Rumination-focused cognitive behaviour therapy for non-responsive chronic depression: an uncontrolled group study
Authors: Moeller Stine Bjerrum , Austin Stephen F. , Hvenegaard Morten , Kistrup Morten , Gran Stine , Watkins Ed
Published: October 2019

Background:

One-third of patients with depression do not respond satisfactorily to treatment, and approximately 20% of all patients treated for depression develop a chronic depression. One approach to more effective treatment of chronic and treatment-resistant depression is to target rumination – an underlying mechanism implicated in the development and maintenance of depression.

Aim:

The purpose of this uncontrolled group study was to investigate the feasibility of individual rumination-focused cognitive behavioural therapy (RfCBT) for patients with chronic and treatment-resistant depression.

Method:

A total of 10 patients with chronic and treatment-resistant depression were offered 12–16 individual sessions of RfCBT. The primary outcome was depressive symptoms as measured by Hamilton Depression Scale at pre-, post- and 3-month follow-up. Secondary symptoms measured included self-reported rumination and worry.

Results:

There was a significant reduction in depressive symptoms (p < 0.05), rumination (p < 0.01) and worry (p < 0.5) from pre- to post-treatment. Half of the participants (n = 5) showed significant reliable change on levels of depressive symptoms post-treatment. The reduction in depressive symptoms, rumination and worry were maintained at follow-up.

Conclusions:

RfCBT was associated with significant reductions in depressive symptoms in a small sample with chronic and treatment-resistant depression. Despite limitations of being a small uncontrolled study with limited follow-up, these results are promising in a difficult to treat population. RfCBT warrants further systematic evaluation.
An ERA5‐Based Model for Estimating Tropospheric Delay and Weighted Mean Temperature Over China With Improved Spatiotemporal Resolutions
Authors: Sun Zhangyu , Zhang Bao , Yao Yibin
Published: October 2019

Tropospheric delay is an important error source in Global Navigation Satellite System (GNSS) positioning and can also be used in water vapor monitoring. Many models have been built to correct tropospheric delays or to convert zenith wet delays to precipitable water vapor. However, these models suffer from limited resolutions (spatial resolution lower than 1° and temporal resolution lower than 6 hr), which affects their performance. The release of European Centre for Medium‐Range Weather Forecasts ReAnalysis 5 (ERA5) provides the opportunity to lift this limit. In this study, we use the ERA5 hourly 0.5° × 0.5° data to build a new model over China, which integrates tropospheric delay correction for GNSS positioning and weighted mean temperature calculation for GNSS meteorology. By modeling the diurnal variations of zenith hydrostatic delay, zenith wet delay, and weighted mean temperature and the seasonal variations in their lapse rates, this model has the state‐of‐the‐art spatial resolution of 0.5° × 0.5° and temporal resolution of 1 hr. We validate this new model by the ERA5 data, the radiosonde data, and the GNSS data in comparison with the canonical GPT2w model. The results show that the new model has better accuracies in terms of root‐mean‐square than the GPT2w model in all parameters. Especially, the new model well captures the diurnal variations in tropospheric delay and weighted mean temperature. This new model provides accurate tropospheric delays and weighted mean temperature simultaneously, which enables GNSS receivers to measure precipitable water vapor directly and also benefits GNSS positioning.
Seismic Evidence for Plume‐Slab Interaction by High‐Resolution Imaging of the 410‐km Discontinuity Under Tonga
Authors: Li Luchen , Chen Yi‐Wei , Zheng Yingcai , Hu Hao , Wu Jonny
Published: October 2019

The Tonga‐Samoa system provides a unique tectonic context to study how a cold subducting slab interacts with a hot rising mantle plume. Here we present a 3‐D high‐resolution image of the 410‐km mantle discontinuity (the 410) using seismic signals excited by deep‐focus earthquakes. The 410 is found to be ~30 km shallower inside the Tonga slab relative to the ambient mantle and ~20 km deeper further to the northwest under Fiji Islands. The downward deflection of the 410 under Fiji supports the hypothesis of a plume migration around the northern edge of the Tonga slab from Samoan hot spot to under Fiji due to fast trench rollback. The 50‐km topography difference in the 410 between the plume and the slab corresponds to a temperature difference of ~500 ± 100 K. The Samoan plume is inferred to be 200 ± 50 K hotter than the ambient mantle and supports a thermal origin for the plume.
Variations of Velocity and Attenuation Anisotropy Structures in the Uppermost Inner Core Beneath the Central Pacific Region
Authors: Qin Jialing , Sun Xinlei , Fan An
Published: October 2019

Using PKIKP and PKiKP travel times and amplitude ratios, we examine the velocity and attenuation anisotropy structures in the uppermost 100 km of the inner core beneath the central Pacific region. Our results indicate a clear change from approximately 180°E to 190°E longitude. Below the western Pacific, velocity anisotropy is weak and attenuation is high (Qp ~200), whereas below the eastern Pacific, velocity anisotropy is strong (3.3%) and attenuation is low (Qp ranges from 400 to 150). Furthermore, the velocity and attenuation anisotropies are correlated with each other. Our results indicate that the growth of the inner core may be coupled with core mantle boundary thermal heterogeneities. The heterogeneities may affect directional heat flow or deformational processes in the uppermost inner core, cause different iron crystal alignments, and result in lateral variations in anisotropy structures.
Structural and Compositional Changes in the Upper Atmosphere Related to the PEDE‐2018 Dust Event on Mars as Observed by MAVEN NGIMS
Authors: Elrod M. K. , Bougher S. W. , Roeten K. , Sharrar R. , Murphy J.
Published: October 2019

The onset of the planet encircling dust event (PEDE‐2018) started around 1 June 2018 as observed by Mars Reconnaissance Orbiter/Mars Color Imager, peaking around 7–10 July and persisting through mid‐October 2018. After the onset of the event, the upper atmosphere underwent significant changes in density and thermal structures. Mars Atmosphere and Volatile Evolution‐Neutral Gas and Ion Mass Spectrometer (MAVEN NGIMS) had a good opportunity to observe these changes from the first detection in the upper atmosphere and throughout the duration of the PEDE. The compositional changes included increased density at a constant altitude for CO2 and Ar, while the O decreased from the peak throughout the decay of the bulk of the PEDE.
Radium Tracing Cross‐Shelf Fluxes of Nutrients in the Northwest Pacific Ocean
Authors: Cho Hyung‐Mi , Kim Guebuem , Kwon Eun Young , Han Yongjin
Published: October 2019

Nutrients in surface waters of the northwest Pacific Ocean are known to be influenced significantly by anthropogenic inputs via the atmosphere. In this study, we evaluated the relative contribution of cross‐shelf fluxes in the northwest Pacific Ocean. The shelf fluxes were estimated by multiplying the 228Ra flux based on inverse modeling by the measured ratios of nutrients to 228Ra. The ratios were obtained from field observations of nutrients and 228Ra in the Yellow Sea and the East China Sea in February 2017 when the water column was fully mixed vertically. The cross‐shelf fluxes are estimated to be approximately 40% of the atmospheric depositional flux of nitrogen and 2 orders of magnitude greater than that of phosphorus. These results suggest that the cross‐shelf fluxes of nutrients are an important, yet previously underappreciated, pathway of nutrients to the North Pacific Ocean, controlling carbon sequestration and biological production.
Assessing the Accuracy of Paleodischarge Estimates for Rivers on Mars
Authors: Morgan Alexander M. , Craddock Robert A.
Published: October 2019

Estimates of river paleodischarges have been used to constrain the former climate of Mars. Paleodischarge has been calculated using mechanistic approximations of the channel bed‐shear stress at the threshold of particle motion or correlative width‐discharge relations derived from empirical terrestrial hydraulic geometry data. We apply both these methods to a study set of gaged terrestrial rivers with field‐measured bankfull properties to assess the reliability of discharge estimates given similar uncertainties as ancient martian rivers. We find that the threshold method yields conservative values, provided a reasonable grain size is used. However, we find that digital elevation models of a similar resolution to those constructed from Context Camera (CTX) data may not be of sufficient resolution to be useful for estimating paleohydrologic conditions. Results from our analysis demonstrate the inherent uncertainties when approximating paleodischarges on Mars and stress the need to consider realistic boundary conditions when determining such values.
Long‐Lasting Penetration Electric Fields during Geomagnetic Storms: Observations and Mechanisms
Authors: Huang Chao‐Song
Published: October 2019

Penetration electric fields originating from the solar wind/magnetosphere, shielding electric fields produced by the Region 2 field‐aligned currents, and disturbance dynamo electric fields produced by disturbance neutral winds are the major disturbance electric fields in the middle‐ and low‐latitude ionosphere during geomagnetic storms. Understanding the interplay of electric fields from different sources is critical for understanding storm time ionospheric electrodynamics. In this study, we analyze ionospheric data measured by five Defense Meteorological Satellite Program satellites in the dusk‐evening sector during a magnetic storm. A peculiar feature in this case is that the vertical ion drift was enhanced in the upward direction by up to 180 m/s, corresponding to the occurrence of an eastward penetration electric field in the equatorial ionosphere, for 14 hr, including 3 hr of the storm main phase and the first 11 hr of the recovery phase. The variations of other ionospheric parameters (the ion density, ion composition, electron temperature, and zonal drift) were well correlated with the variation of the vertical ion drifts, providing further evidence of prolonged penetration electric fields. Observations of short‐lived penetration electric fields are also presented, and the causes for short‐lived penetration electric fields are discussed. Important issues on the shielding effects are addressed. Scenarios for occurrence of long‐lasting penetration electric fields are proposed. Some outstanding problems associated with penetration electric fields are listed for future studies.
Electrostatic Spacecraft Potential Structure and Wake Formation Effects for Characterization of Cold Ion Beams in the Earth's Magnetosphere
Authors: Toledo‐Redondo S. , Lavraud B. , Fuselier S. A. , André M. , Khotyaintsev Yu. V. , Nakamura R. , Escoubet C. P. , Li W. Y. , Torkar K. , Cipriani F. , Barrie A. C. , Giles B. , Moore T. E. , Gershman D. , Lindqvist P.‐A. , Ergun R. E. , Russell C. T. , Burch J. L.
Published: October 2019

Cold plasma (up to few tens of electron volts) of ionospheric origin is present most of the time, in most of the regions of the Earth's magnetosphere. However, characterizing it using in situ measurements is difficult, owing to spacecraft electrostatic charging, as often this charging is at levels comparable to or even higher than the equivalent energy of the cold plasma. To overcome this difficulty, active potential control devices are usually placed on spacecraft that artificially reduce spacecraft charging. The electrostatic potential structure around the spacecraft is often assumed to be spherically symmetric, and corrections are applied to the measured particle distribution functions. In this work, we show that large deviations from the spherical model are present, owing to the presence of long electric field booms. We show examples using Magnetospheric MultiScale spacecraft measurements of the electrostatic potential structure and its effect on the measurement of cold ion beams. Overall, we find that particle detectors underestimate the cold ion density under certain conditions, even when their bulk kinetic energy exceeds the equivalent spacecraft potential energy and the ion beam reaches the spacecraft. Active potential control helps in reducing this unwanted effect, but we show one event with large cold ion density (∼10 cm−3) where particle detectors provide density estimates a factor of 3–5 below the density estimated from the plasma frequency. Understanding these wake effects indirectly constrains some properties of the magnetospheric cold ion component, such as their drift energy, direction, and temperature.
Lunar Impact Glasses: Probing the Moon's Surface and Constraining its Impact History
Authors: Zellner N. E. B.
Published: October 2019

Lunar impact glasses, formed during impact events when the regolith is quenched during the ejecta's ballistic flight, are small samples whose information can lead to important advances in studies of the Moon. For example, they provide evidence that constrains both the compositional evolution of the lunar crust and the timing of the lunar impact flux starting at ~4,000 million years ago. They are abundant in the lunar regolith and retain geochemical information that tells us where and when they formed. Thus, they provide important details about areas of the Moon both sampled and not sampled by Apollo or Luna missions or lunar meteorites. Additionally, as a result of these glasses possessing a chemical memory of formation location and age, studies of lunar impact glasses provide a foundation on which to conduct studies of impact glasses from other planetary bodies. A summary of past and current lunar impact glass investigations, using glasses from the Apollo 11, 12, 14, 15, 16, and 17 regoliths, along with plans for future work, will be presented.
High‐Resolution Thermal Environment of Recurring Slope Lineae in Palikir Crater, Mars, and Its Implications for Volatiles
Authors: Schorghofer N. , Levy J.S. , Goudge T.A.
Published: October 2019

A thermophysical model for rough terrain is developed that is capable of processing spatial domains of megapixel size. This computational advance makes it possible to characterize thermal environments on Mars at unprecedented scale and at a resolution of 1 m per pixel. The model is applied to Palikir Crater, Mars, where many recurring slope lineae (RSL) are located, often in bedrock alcoves. In areas with RSL, subsurface water ice is not stable, that is, any subsurface ice is lost to the atmosphere in the long term. On large portions of the craters walls, water frost accumulates continuously for up to hundreds of sols each Mars year, but no relation is found between the location of RSL and seasonal water frost accumulation. Some RSL do not have access to even 1 m2 of water frost, at any time of the year. Where water frost is present, it stops accumulating in early southern spring at the latest, long before major RSL activity. Based on the model results, neither CO2 frost, perennial subsurface ice, nor seasonal water frost patches (>1 m2) are connected with RSL activity.
Extensive Polygonal Fracture Network in Siccar Point group Strata: Fracture Mechanisms and Implications for Fluid Circulation in Gale Crater, Mars
Authors: Kronyak R. E. , Kah L. C. , Miklusicak N. B. , Edgett K. S. , Sun V. Z. , Bryk A. B. , Williams R. M. E.
Published: October 2019

Rock fractures are indicators of stress release within geologic systems, and fracture morphologies can commonly be used to infer formation conditions. Polygonal fractures are common in isotropic, contractional stress regimes such as in rocks exposed at the surface of a planet undergoing thermal cycling or in sedimentary substrates undergoing repeated wetting and drying. Such polygonal fracture systems, on centimeter to decameter scales, have been widely documented on Mars. Utilizing a combination of orbital‐ and ground‐based images, we report a laterally extensive polygonal fracture network that occurs within siliciclastic rocks of the lowermost Siccar Point group, Gale crater, Mars. The Siccar Point group is exposed over approximately 20 km2 in northwest Gale crater, where it unconformably overlies eroded strata of Mount Sharp (Aeolis Mons) and reflects likely aeolian deposition along the lower flanks of Mount Sharp. Images reveal an extensive network of erosionally resistant polygons, approximately 7.5 m across, that exhibit interior angles (i.e., fracture intersections) with modes at 90° and 120°. Polygon morphology indicates that fractures formed during multiple cycles of expansion and contraction, which is attributed to desiccation and subsequent recharge of near‐surface groundwater. The erosional resistance of preserved fractures is inferred to reflect postfracture diagenetic fluid flow along the sub–Siccar Point group unconformity and cementation. Evidence for multiple fluid events in the relatively young strata of the Siccar Point group requires a protracted history of fluid stability in Gale crater.
Chlorate as a Potential Oxidant on Mars: Rates and Products of Dissolved Fe(II) Oxidation
Authors: Mitra Kaushik , Catalano Jeffrey G.
Published: October 2019

Oxychlorine species are globally widespread across the Martian surface. Despite their ubiquitous presence, the ability of oxychlorine species to serve as oxidants on Mars has largely been unexplored. While perchlorate is kinetically inert, chlorate may be a critical Fe(II) oxidant on Mars. However, the timescale over which chlorate may oxidize Fe(II) and the mineral products formed in Mars‐relevant fluids are unclear. Fe(II) oxidation by chlorate was thus investigated in magnesium chloride, sulfate, and perchlorate fluids under neutral to acidic conditions for different total Fe(II) and background salt concentrations. The results show near‐complete Fe(II) oxidation within approximately 2 to 4 weeks, accompanied by formation of the Fe(III) minerals goethite, lepidocrocite, akaganeite, and jarosite. The Fe(II) oxidation rate and the mineral products depend on Fe(II) concentration, the composition and concentration of the background salt, and the acidity of the solution. Calibration of an existing rate law to lower temperatures well reproduces the observed oxidation kinetics in all fluid compositions and allows prediction of the rate of Fe(II) oxidation by chlorate under diverse Mars‐relevant conditions. Rate comparisons demonstrates that chlorate can oxidize Fe(II) substantially faster than O2and on similar or shorter timescales than ultraviolet light. Notably, chlorate causes rapid oxidation under acidic conditions, unlike other oxidants. Chlorate may thus represent an important abiotic Fe(II) oxidant on Mars. The expected coassociation of chlorate with perchlorate may allow for its percolation into the subsurface during brine migration, leading to oxidation in regions that are cutoff from ultraviolet radiation and atmospherically derived oxidants.
Intelligent metasurface imager and recognizer
Authors: Li Lianlin , Shuang Ya , Ma Qian , Li Haoyang , Zhao Hanting , Wei Menglin , Liu Che , Hao Chenglong , Qiu Cheng-Wei , Cui Tie Jun
Published: October 2019

There is an increasing need to remotely monitor people in daily life using radio-frequency probe signals. However, conventional systems can hardly be deployed in real-world settings since they typically require objects to either deliberately cooperate or carry a wireless active device or identification tag. To accomplish complicated successive tasks using a single device in real time, we propose the simultaneous use of a smart metasurface imager and recognizer, empowered by a network of artificial neural networks (ANNs) for adaptively controlling data flow. Here, three ANNs are employed in an integrated hierarchy, transforming measured microwave data into images of the whole human body, classifying specifically designated spots (hand and chest) within the whole image, and recognizing human hand signs instantly at a Wi-Fi frequency of 2.4 GHz. Instantaneous in situ full-scene imaging and adaptive recognition of hand signs and vital signs of multiple non-cooperative people were experimentally demonstrated. We also show that the proposed intelligent metasurface system works well even when it is passively excited by stray Wi-Fi signals that ubiquitously exist in our daily lives. The reported strategy could open up a new avenue for future smart cities, smart homes, human-device interaction interfaces, health monitoring, and safety screening free of visual privacy issues.
Distinct nitrogen cycling and steep chemical gradients in Trichodesmium colonies
Authors: Klawonn Isabell , Eichner Meri J , Wilson Samuel T , Moradi Nasrollah , Thamdrup Bo , Kümmel Steffen , Gehre Matthias , Khalili Arzhang , Grossart Hans-Peter , Karl David M , Ploug Helle
Published: October 2019

Trichodesmium is an important dinitrogen (N2)-fixing cyanobacterium in marine ecosystems. Recent nucleic acid analyses indicate that Trichodesmium colonies with their diverse epibionts support various nitrogen (N) transformations beyond N2 fixation. However, rates of these transformations and concentration gradients of N compounds in Trichodesmium colonies remain largely unresolved. We combined isotope-tracer incubations, micro-profiling and numeric modelling to explore carbon fixation, N cycling processes as well as oxygen, ammonium and nitrate concentration gradients in individual field-sampled Trichodesmium colonies. Colonies were net-autotrophic, with carbon and N2 fixation occurring mostly during the day. Ten percent of the fixed N was released as ammonium after 12-h incubations. Nitrification was not detectable but nitrate consumption was high when nitrate was added. The consumed nitrate was partly reduced to ammonium, while denitrification was insignificant. Thus, the potential N transformation network was characterised by fixed N gain and recycling processes rather than denitrification. Oxygen concentrations within colonies were ~60–200% air-saturation. Moreover, our modelling predicted steep concentration gradients, with up to 6-fold higher ammonium concentrations, and nitrate depletion in the colony centre compared to the ambient seawater. These gradients created a chemically heterogeneous microenvironment, presumably facilitating diverse microbial metabolisms in millimetre-sized Trichodesmium colonies.
Transient exposure to novel high temperatures reshapes coastal phytoplankton communities
Authors: Kling Joshua D , Lee Michael D , Fu Feixue , Phan Megan D , Wang Xinwei , Qu Pingping , Hutchins David A
Published: October 2019

Average sea surface temperatures are expected to rise 4° this century, and marine phytoplankton and bacterial community composition, biogeochemical rates, and trophic interactions are all expected to change in a future warmer ocean. Thermal experiments typically use constant temperatures; however, weather and hydrography cause marine temperatures to fluctuate on diel cycles and over multiple days. We incubated natural communities of phytoplankton collected from California coastal waters during spring, summer, and fall under present-day and future mean temperatures, using thermal treatments that were either constant or fluctuated on a 48 h cycle. As assayed by marker-gene sequencing, the emergent microbial communities were consistent within each season, except when culture temperatures exceeded the highest temperature recorded in a 10-year local thermal dataset. When temperature treatments exceeded the 10-year maximum the phytoplankton community shifted, becoming dominated by diatom amplicon sequence variants (ASVs) not seen at lower temperatures. When mean temperatures were above the 10-year maximum, constant and fluctuating regimes each selected for different ASVs. These findings suggest coastal microbial communities are largely adapted to the current range of temperatures they experience. They also suggest a general hypothesis whereby multiyear upper temperature limits may represent thresholds, beyond which large community restructurings may occur. Now inevitable future temperature increases that exceed these environmental thresholds, even temporarily, may fundamentally reshape marine microbial communities and therefore the biogeochemical cycles that they mediate.
Abnormalities of confidence in psychiatry: an overview and future perspectives
Authors: Hoven Monja , Lebreton Maël , Engelmann Jan B. , Denys Damiaan , Luigjes Judy , van Holst Ruth J.
Published: October 2019

Our behavior is constantly accompanied by a sense of confidence and its’ precision is critical for adequate adaptation and survival. Importantly, abnormal confidence judgments that do not reflect reality may play a crucial role in pathological decision-making typically seen in psychiatric disorders. In this review, we propose abnormalities of confidence as a new model of interpreting psychiatric symptoms. We hypothesize a dysfunction of confidence at the root of psychiatric symptoms either expressed subclinically in the general population or clinically in the patient population. Our review reveals a robust association between confidence abnormalities and psychiatric symptomatology. Confidence abnormalities are present in subclinical/prodromal phases of psychiatric disorders, show a positive relationship with symptom severity, and appear to normalize after recovery. In the reviewed literature, the strongest evidence was found for a decline in confidence in (sub)clinical OCD, and for a decrease in confidence discrimination in (sub)clinical schizophrenia. We found suggestive evidence for increased/decreased confidence in addiction and depression/anxiety, respectively. Confidence abnormalities may help to understand underlying psychopathological substrates across disorders, and should thus be considered transdiagnostically. This review provides clear evidence for confidence abnormalities in different psychiatric disorders, identifies current knowledge gaps and supplies suggestions for future avenues. As such, it may guide future translational research into the underlying processes governing these abnormalities, as well as future interventions to restore them.
Maternal valproic acid exposure leads to neurogenesis defects and autism-like behaviors in non-human primates
Authors: Zhao Hui , Wang Qiqi , Yan Ting , Zhang Yu , Xu Hui-juan , Yu Hao-peng , Tu Zhuchi , Guo Xiangyu , Jiang Yong-hui , Li Xiao-jiang , Zhou Huihui , Zhang Yong Q.
Published: October 2019

Despite the substantial progress made in identifying genetic defects in autism spectrum disorder (ASD), the etiology for majority of ASD individuals remains elusive. Maternal exposure to valproic acid (VPA), a commonly prescribed antiepileptic drug during pregnancy in human, has long been considered a risk factor to contribute to ASD susceptibility in offspring from epidemiological studies in humans. The similar exposures in murine models have provided tentative evidence to support the finding from human epidemiology. However, the apparent difference between rodent and human poses a significant challenge to extrapolate the findings from rodent models to humans. Here we report for the first time the neurodevelopmental and behavioral outcomes of maternal VPA exposure in non-human primates. Monkey offspring from the early maternal VPA exposure have significantly reduced NeuN-positive mature neurons in prefrontal cortex (PFC) and cerebellum and the Ki67-positive proliferating neuronal precursors in the cerebellar external granular layer, but increased GFAP-positive astrocytes in PFC. Transcriptome analyses revealed that maternal VPA exposure disrupted the expression of genes associated with neurodevelopment in embryonic brain in offspring. VPA-exposed juvenile offspring have variable presentations of impaired social interaction, pronounced stereotypies, and more attention on nonsocial stimuli by eye tracking analysis. Our findings in non-human primates provide the best evidence so far to support causal link between maternal VPA exposure and neurodevelopmental defects and ASD susceptibility in humans.
Ultrahigh resolution and color gamut with scattering-reducing transmissive pixels
Authors: Lee June Sang , Park Ji Yeon , Kim Yong Hwan , Jeon Seokwoo , Ouellette Olivier , Sargent Edward H. , Kim Dong Ha , Hyun Jerome K.
Published: October 2019

While plasmonic designs have dominated recent trends in structural color, schemes using localized surface plasmon resonances and surface plasmon polaritons that simultaneously achieve high color vibrancy at ultrahigh resolution have been elusive because of tradeoffs between size and performance. Herein we demonstrate vibrant and size-invariant transmissive type multicolor pixels composed of hybrid TiOx-Ag core-shell nanowires based on reduced scattering at their electric dipolar Mie resonances. This principle permits the hybrid nanoresonator to achieve the widest color gamut (~74% sRGB area coverage), linear color mixing, and the highest reported single color dots-per-inch (58,000~141,000) in transmission mode. Exploiting such features, we further show that an assembly of distinct nanoresonators can constitute a multicolor pixel for use in multispectral imaging, with a size that is ~10-folds below the Nyquist limit using a typical high NA objective lens.
Genotypic performance of Australian durum under single and combined water-deficit and heat stress during reproduction
Authors: Liu Haipei , Able Amanda J. , Able Jason A.
Published: October 2019

In Mediterranean environments, water deficiency and heat during reproduction severely limit cereal crop production. Our research investigated the effects of single and combined pre-anthesis water-deficit stress and post-anthesis heat stress in ten Australian durum genotypes, providing a systematic evaluation of stress response at the molecular, physiological, grain quality and yield level. We studied leaf physiological traits at different reproductive stages, evaluated the grain yield and quality, and the associations among them. We profiled the expression dynamics of two durum microRNAs and their protein-coding targets (auxin response factors and heat shock proteins) involved in stress adaptation. Chlorophyll content, stomatal conductance and leaf relative water content were mostly reduced under stress, however, subject to the time-point and genotype. The influence of stress on grain traits (e.g., protein content) also varied considerably among the genotypes. Significant positive correlations between the physiological traits and the yield components could be used to develop screening strategies for stress improvement in breeding. Different expression patterns of stress-responsive microRNAs and their targets in the most stress-tolerant and most stress-sensitive genotype provided some insight into the complex defense molecular networks in durum. Overall, genotypic performance observed indicates that different stress-coping strategies are deployed by varieties under various stresses.
Molecular dissection of resistance gene cluster and candidate gene identification of Pl17 and Pl19 in sunflower by whole-genome resequencing
Authors: Ma Guojia , Song Qijian , Underwood William R. , Zhang Zhiwei , Fiedler Jason D. , Li Xuehui , Qi Lili
Published: October 2019

Sunflower (Helianthus annuus L.) production is challenged by different biotic and abiotic stresses, among which downy mildew (DM) is a severe biotic stress that is detrimental to sunflower yield and quality in many sunflower-growing regions worldwide. Resistance against its infestation in sunflower is commonly regulated by single dominant genes. Pl17 and Pl19 are two broad-spectrum DM resistance genes that have been previously mapped to a gene cluster spanning a 3.2 Mb region at the upper end of sunflower chromosome 4. Using a whole-genome resequencing approach combined with a reference sequence-based chromosome walking strategy and high-density mapping populations, we narrowed down Pl17 to a 15-kb region flanked by SNP markers C4_5711524 and SPB0001. A prospective candidate gene HanXRQChr04g0095641 for Pl17 was identified, encoding a typical TNL resistance gene protein. Pl19 was delimited to a 35-kb region and was approximately 1 Mb away from Pl17, flanked by SNP markers C4_6676629 and C4_6711381. The only gene present within the delineated Pl19 locus in the reference genome, HanXRQChr04g0095951, was predicted to encode an RNA methyltransferase family protein. Six and eight SNP markers diagnostic for Pl17 and Pl19, respectively, were identified upon evaluation of 96 diverse sunflower lines, providing a very useful tool for marker-assisted selection in sunflower breeding programs.
Seed Priming with Melatonin Improves the Seed Germination of Waxy Maize under Chilling Stress via Promoting the Antioxidant System and Starch Metabolism
Authors: Cao Qingjun , Li Gang , Cui Zhengguo , Yang Fentuan , Jiang Xiaoli , Diallo Lamine , Kong Fanli
Published: October 2019

Chilling stress is one of the major abiotic stresses affecting waxy maize plant growth. Melatonin (MT) is able to improve tolerance to abiotic stress in plants. To investigate the effects of seed priming with MT on tolerance to chilling stress in waxy maize, the seed germination characteristics and physiological parameters were tested with varied MT concentrations (0, 50, 100 µM) and treatment times (12, 24 h) at ambient (25 °C) and chilling (13 °C) temperature. MT primed seeds significantly enhanced the germination potential (by 20.29% and 50.71%, respectively), germination rate (by 20.88% and 33.72%), and increased the radicle length (by 90.73% and 217.14%), hypocotyl length (by 60.28% and 136.14%), root length (by 74.59% and 108.70%), and seed vigor index (46.13%, 63.81%), compared with the non-priming seeds under chilling stress. No significant difference was found in priming time between primed and non-primed seeds. In addition, lower H2O2 and malondialdehyde concentrations, increased antioxidant enzyme activities (superoxide dismutase, peroxidase, catalase and ascorbateperoxidase), and promoted starch metabolism were found in primed seeds compared to non-primed ones. It was suggested that seed priming with MT improved waxy maize seed germination under chilling stress through improving antioxidant system and starch metabolism, which protected from oxidative damage.