bluuebunny/crossref_metadata_2025 huggingface dataset:
Do 2‐year changes in superior frontal gyrus and global brain atrophy affect cognition?
Authors: Valdés Hernández Maria del C. , Reid Stuart , Mikhael Shadia , Pernet Cyril ,   The Alzheimer's Disease Neuroimaging Initiative
Published: August 2018

Introduction

Metabolic alterations to the superior frontal gyrus (SFG) have been linked to cognitive decline. Whether these indicate structural atrophy, which could be screened for at a larger scale using noninvasive structural imaging, is unknown.

Methods

We assessed annual structural magnetic resonance imaging scans and cognitive data from 3 consecutive years from 204 participants from the AD Neuroimaging Initiative database (mean age 72.24 [8.175] years). We evaluated associations between brain structural changes and performance in the Montreal Cognitive Assessment, Everyday Cognition Visuospatial subtest (ECog Visuospatial), and Functional Assessment Questionnaire.

Results

Changes in the surface area of the SFG were associated with changes in the outcome of the ECog Visuospatial test (P < .05), but an inconsistent pattern of association was found between the 2‐year global brain atrophy progression and changes in the outcome from the three cognitive tests selected.

Discussion

The extent into which (and if) changes in the SFG influence cognition warrant further evaluation in a larger period in more heterogeneous population.
Vitamin D partially reverses the increase in p‐NF‐κB/p65 immunocontent and interleukin‐6 levels, but not in acetylcholinesterase activity in hippocampus of adult female ovariectomized rats
Authors: Siebert Cassiana , Bertó Carolina Gessinger , Ferreira Fernanda Silva , Moreira Daniella de S. , dos Santos Tiago Marcon , Wyse Angela T.S.
Published: August 2018

The aim of this study was to verify the effects of ovariectomy (OVX) and/or vitamin D supplementation (VIT D) on inflammatory and cholinergic parameters in hippocampus, as well as on serum estradiol and VIT D levels of rats. Ninety‐day‐old female Wistar rats were randomly divided into four groups: SHAM, OVX, VIT D or OVX + VIT D. Thirty days after OVX, VIT D (500 IU/kg/day) was supplemented by gavage, for 30 days. Approximately 12 h after the last VIT D administration, rats were euthanized and hippocampus and serum were obtained for further analyses. Results showed that OVX rats presented a decrease in estradiol levels when compared to control (SHAM). There was an increase in VIT D levels in the groups submitted to VIT D supplementation. OVX increased the immunocontent of nuclear p‐NF‐κB/p65, TNF‐α and IL‐6 levels. VIT D partially reversed the increase in p‐NF‐κB/p65 immunocontent and IL‐6 levels. Regarding cholinergic system, OVX caused an increase in acetylcholinesterase activity without changing acetylcholinesterase and choline acetyltransferase immunocontents. VIT D did not reverse the increase in acetylcholinesterase activity caused by OVX. These results demonstrate that OVX alters inflammatory and cholinergic parameters and that VIT D supplementation, at the dose used, partially reversed the increase in immunocontent of p‐NF‐Kb/p65 and IL‐6 levels, but it was not able to reverse other parameters studied. Our findings may help in the understanding of the brain changes that occurs in post menopause period and open perspectives for futures research involving VIT D therapies.
Promoting adolescent health: insights from developmental and communication neuroscience
Authors: PEI RUI , KRANZLER ELISSA C. , SULEIMAN AHNA BALLONOFF , FALK EMILY B.
Published: August 2018

Adolescence is a period of remarkable psychosocial and neural development. Many life-long health habits are established during adolescence, making it a window of opportunity for health promotion. One way to promote adolescent health is through mass and social media campaigns. Although some health media campaigns that target adolescents are effective in changing health-relevant cognitions and behaviors, there is considerable room for improving these outcomes. Recent advancements combining neuroimaging tools and health persuasion have suggested key neural mechanisms underlying behavior change and retransmission of health-relevant ideas and norms in adults. This line of work highlights the integral role of the brain's value system in health persuasion and its importance for improving campaign design and effectiveness. Less is known about how these insights could be leveraged to inform adolescent health persuasion. In this article, we review what is known and unknown about the development of the brain's value system and its connections with cognitive control and social cognition systems across adolescence. Combining these insights, we propose that neuroimaging tools offer unique possibilities that could improve adolescent media health campaigns and promote adolescent well-being.
The Strategic Teamwork for Effective Practice Mentor Development Program (STEP-MDP): Expanding capacity for clinical and translational science by investing in research staff
Authors: Denicola Christine , Altshuler Lisa , Denicola Gabrielle , Zabar Sondra
Published: August 2018

Introduction

Research staff are critical to productive translational research teams, yet their professional development is rarely formally addressed.

Methods

We created Strategic Teamwork for Effective Practice Mentor Development Program (STEP-MDP) to promote skills development and build a community of practice. We ran and evaluated the STEP-MDP for 32 participants, which consisted of workshops focusing on team communication and mentorship/coaching skills.

Results

We found that STEP-MDP had a long-term positive impact on participants and their teams.

Conclusion

This program facilitated the professional development of research staff.
The projected burden of complex surgical site infections following hip and knee arthroplasties in adults in the United States, 2020 through 2030
Authors: Wolford Hannah M. , Hatfield Kelly M. , Paul Prabasaj , Yi Sarah H. , Slayton Rachel B.
Published: August 2018

Background

As the US population ages, the number of hip and knee arthroplasties is expected to increase. Because surgical site infections (SSIs) following these procedures contribute substantial morbidity, mortality, and costs, we projected SSIs expected to occur from 2020 through 2030.

Methods

We used a stochastic Poisson process to project the number of primary and revision arthroplasties and SSIs. Primary arthroplasty rates were calculated using annual estimates of hip and knee arthroplasty stratified by age and gender from the 2012–2014 Nationwide Inpatient Sample and standardized by census population data. Revision rates, dependent on time from primary procedure, were obtained from published literature and were uniformly applied for all ages and genders. Stratified complex SSI rates for arthroplasties were obtained from 2012–2015 National Healthcare Safety Network data. To evaluate the possible impact of prevention measures, we recalculated the projections with an SSI rate reduced by 30%, the national target established by the US Department of Health and Human Services (HHS).

Results

Without a reduction in SSI rates, we projected an increase in complex SSIs following hip and knee arthroplasty of 14% between 2020 and 2030. We projected a total burden of 77,653 SSIs; however, meeting the 30% rate reduction could prevent 23,297 of these SSIs.

Conclusions

Given current SSI rates, we project that complex SSI burden for primary and revision arthroplasty may increase due to an aging population. Reducing the SSI rate to the national HHS target could prevent 23,000 SSIs and reduce subsequent morbidity, mortality, and Medicare costs.
High prevalence of ESBL-positive bacteria in an obstetrics emergency hospital and neonatal care unit—Haiti, 2016
Authors: Chaintarli Katerina , Lenglet Annick , Beauzile Bregeneve Dabord , Senat-Delva Rodnie , Mabou Marie-Marcelle , Martino Chiara , Berthet Marine , Wong Sidney , Hopman Joost
Published: August 2018

A point-prevalence survey of mothers and neonates admitted to an obstetrics emergency hospital in Port-au-Prince, Haiti, revealed that 13 of 127 gram-negative bacteria isolates (10%) from rectal swabs were ESBL-positive in women and 30 of 59 gram-negative bacteria isolates (51%) from rectal swabs were ESBL-positive in neonates. Length of hospital stay and antibiotic consumption were risk factors for ESBL colonization.
Contesting the Material Turn; or, The Persistence of Agency
Authors: López Alfred J.
Published: August 2018

This essay begins by asking whether the new materialism, as currently constituted, can say anything useful about race, given that the most widely read texts recognized as belonging to this emerging field pointedly do not. Put another way, this essay examines possibilities for the reading of the raced enfleshed human subject in and beyond the parameters of the new materialism. The essay’s first section locates the raced enfleshed subject as latent (if not actively suppressed) entity in existing new materialist work. The latter half turns to questions of possibility, especially the question of whether a much older, precluded, or occluded voice is already “speaking through” the so-called materialist turn, challenging it as a way of contesting its own (attempted, failed) erasure from the metaphysical founding scene of the liberal humanist subject that informs the material turn.
A Class of Parabolic Equations Driven by the Mean Curvature Flow
Authors: de Araujo Anderson L. A. , Montenegro Marcelo
Published: August 2018

We study a class of parabolic equations which can be viewed as a generalized mean curvature flow acting on cylindrically symmetric surfaces with a Dirichlet condition on the boundary. We prove the existence of a unique solution by means of an approximation scheme. We also develop the theory of asymptotic stability for solutions of general parabolic problems.
How Homo economicus lost her mind and how we can revive her
Authors: DeScioli Peter
Published: August 2018

The target article by Boyer & Petersen (B&P) contributes a vital message: that people have folk economic theories that shape their thoughts and behavior in the marketplace. This message is all the more important because, in the history of economic thought, Homo economicus was increasingly stripped of mental capacities. Intuitive theories can help restore the mind of Homo economicus.
People are intuitive economists under the right conditions
Authors: Jern Alan
Published: August 2018

Boyer & Petersen (B&P) argue that a “rudimentary exchange psychology” is responsible for many of people's folk-economic beliefs that are at odds with the consensus views of economists. However, they focus primarily on macroeconomic beliefs. I argue that the same rudimentary exchange psychology could be expected to produce fairly accurate microeconomic intuitions. Existing evidence supports this prediction.
Adding culture and context improves evolutionary theorizing about human cognition
Authors: McNamara Rita Anne , Fischer Ronald
Published: August 2018

Boyer & Petersen (B&P) lay out an evolutionarily grounded framework to produce concrete, testable predictions about economic phenomena. We commend this step forward, but suggest the framework requires more consideration of cultural contexts that provide necessary input for cognitive systems to operate on. We discuss the role of culture when examining both evolved cognitive systems and social exchange contexts.
Folk-economics: Inherited biases or misapplication of everyday experience?
Authors: Ross Don
Published: August 2018

Evidence for an EEA-derived domain-specific inference system must point to an active, latent representational structure. Otherwise we need to hypothesize only passive, virtual belief not over-ridden on the basis of the individual's experience. The folk economic beliefs identified by Boyer & Petersen (B&P), being with one exception about macroeconomics, might be virtual beliefs that people extrapolate across the micro–macro scale shift based on their experiences with markets.
What is seen and what is not seen in the economy: An effect of our evolved psychology
Authors: Boyer Pascal , Petersen Michael Bang
Published: August 2018

Specific features of our evolved cognitive architecture explain why some aspects of the economy are “seen” and others are “not seen.” Drawing from the commentaries of economists, psychologists, and other social scientists on our original proposal, we propose a more precise model of the acquisition and spread of folk-beliefs about the economy. In particular, we try to provide a clearer delimitation of the field of folk-economic beliefs (sect. R2) and to dispel possible misunderstandings of the role of variation in evolutionary psychology (sect. R3). We also comment on the difficulty of explaining folk-economic beliefs in terms of domain-general processes or biases (sect. R4), as developmental studies show how encounters with specific environments calibrate domain-specific systems (sect. R5). We offer a more detailed description of the connections between economic beliefs and political psychology (sect. R6) and of the probable causes of individual variation in that domain (sect. R7). Taken together, these arguments point to a better integration or consilience between economics and human evolution (sect. R8).
On extensions of van Hamme's conjectures
Authors: He Bing
Published: August 2018

Some congruences on conjectures of van Hamme are established. These results give partial answers to some of Swisher's conjectures.
Acute rheumatic fever presenting with severe endocarditis involving four valves, and ventricular tachycardia
Authors: Ramoğlu Mehmet G. , Epçaçan Serdar , Yeşilbaş Osman
Published: August 2018

Acute rheumatic fever is the most commonly acquired heart disease in developing countries. The most common cardiac presentation is valvular disease. Although some rhythm disturbances may occur during the acute stages of the disease, ventricular tachycardia is extremely rare. Here, a case of acute rheumatic fever with severe endocarditis involving four valves and ventricular tachycardia is presented.
On the givenness of OV word order: a (re)examination of OV/VO variation in Old English
Authors: STRUIK TARA , VAN KEMENADE ANS
Published: August 2018

OV/VO variation in the history of English has been a long-debated issue. Where earlier approaches were concerned with the grammatical status of the variation (see van Kemenade 1987; Pintzuk 1999 and many others), the debate has shifted more recently to explaining the variation from a pragmatic perspective (see Bech 2001; Taylor & Pintzuk 2012a), focusing on the given-before-new hypothesis (Gundel 1988) and its consequences for OV/VO. While the work by Taylor & Pintzuk (2012a) focuses specifically on the newness of VO orders, the present study is particularly concerned with the givenness of OV word order. It is hypothesized that OV orders are the result of leftward movement from VO orders, triggered by givenness. A corpus study on a database of subclauses with two verbs and a direct object, collected from the YCOE (Tayloret al.2003) corpus, and subsequent multinomial regression analysis within a generalized linear mixed model shows that OV word order is reserved for given objects, while VO objects are much more mixed in terms of information structure. We argue that these results are more in line with an analysis which derives all occurring word orders from a VO base than an analysis which proposes the opposite.
A systematic review of community Leg Clubs for patients with chronic leg ulcers
Authors: Abu Ghazaleh Haya , Artom Micol , Sturt Jackie
Published: August 2018

Aim

Appraise the evidence on the outcomes of Leg Clubs on ulcer healing, psychosocial outcomes, patient safety, cost and experiences of Leg Club members.

Background

The Leg Club is a community-based social model of care in 30 UK locations and nine overseas for treating patients with chronic leg wounds. However, its cumulative effectiveness has not been reviewed to-date.

Methods

Systematic review of primary research relating to the impact and quality of care of Leg Clubs treating patients with leg ulcers. Six electronic databases were systematically searched using the MeSH term ‘leg ulcer’, including other representative terms, in combination with ‘Leg Club’. The quality of individual studies was assessed using appraisal tools. The confidence in the quantitative evidence was evaluated using Grading of Recommendations Assessment, Development and Evaluation (GRADE); and the Confidence in the Evidence from Reviews of Qualitative Research (CERQual) assessed the quality of qualitative findings.

Findings

A total of 17 relevant publications were identified. Out of the 17 articles, four publications represent findings from randomised controlled trial (RCT). Thus, evidence from 14 independent studies involving at least 532 participants were included in the synthesis of this review. The quality of the evidence varied across the different outcomes and were mostly low or of very low quality. Findings from one underpowered RCT from Australia reporting on clinical, patient-reported outcomes and economic outcomes were evaluated as moderate quality. Studies indicate that the Leg Club model has a positive impact on ulcer healing and recurrence, mood, sleep, quality of life and pain. Moreover, only three studies assessed wound infections and reported no infections had occurred during treatment at the Leg Clubs. Economic evaluations find Leg Clubs to be probably more cost-effective than usual care. Both patients and nurses projected positive views about the Leg Clubs, with particular emphasis on improved social interactions and delivery of patient-centred care.
Heavy Air Pollution May Lower Cognitive Test Scores
Authors: Cartier Kimberly
Published: August 2018

A new study found that verbal and math test scores in China dropped with reduced air quality. The effects were especially pronounced for men and elderly populations.
Investigation of the Causes of the Longitudinal and Solar Cycle Variation of the Electron Density in the Bering Sea and Weddell Sea Anomalies
Authors: Richards P. G. , Meier R. R. , Chen Shihping , Dandenault P.
Published: August 2018

This paper investigates and quantifies the longitudinal, solar cyclical, and diurnal variation of the ionosphere peak electron density observed by six ionosondes located between 18 and 151°E near 60°N. Embedded within this region is the Bering Sea anomaly (BSA) where the midnight peak electron density exceeds the midday peak electron density in summer. The BSA is a region West of Alaska extending from approximately 100° to 200° east geographic longitude and 55° to 70° north geographic latitude at its widest. By comparing a physical model with ionosonde data from the 1970s and 1980s, it is found that longitudinal changes in the neutral winds and neutral densities are the most likely explanation for the electron density variation between 18 and 151°E near 60°N. Longitudinal differences in magnetic declination and inclination are small and have a negligible effect on the electron density behavior. Our definition of and the behavior of the BSA are analogous to the Weddell Sea anomaly (WSA), a region in the Southern Hemisphere where the midnight peak electron density also exceeds the midday peak electron density in summer. Although the overall BSA electron density is a factor of 2 smaller than that in the WSA, the two anomalies have similar midnight to midday electron density ratios. It is found that the BSA gets stronger with increasing solar activity, while the WSA gets weaker. It is also demonstrated that including vibrationally excited N2 in an ionosphere model is crucial for producing the observed midnight to midday electron density ratios.
Particle‐in‐Cell Simulations of the Fast Magnetosonic Mode in a Dipole Magnetic Field: 1‐D Along the Radial Direction
Authors: Min Kyungguk , Liu Kaijun , Denton Richard E. , Boardsen Scott A.
Published: August 2018

An electromagnetic particle‐in‐cell code is used to investigate self‐consistent evolution of the fast magnetosonic mode in a one‐dimensional configuration along the radial direction in a dipole background magnetic field. A previous observation of this wave mode is used to select the simulation parameters. A partial shell velocity distribution of energetic protons with a moderate pitch angle anisotropy is used to excite the waves self‐consistently. Consistent with local linear theory analysis, wave growth occurs only at exact harmonics of the local proton cyclotron frequency, Ωp. However, radial propagation quickly removes the waves from the region where they can grow, leading to a time scale of wave amplification much longer than that predicted by linear theory. In addition, radial propagation from multiple wave sources makes the frequency spectrum measured at a single point much broader. The warm background plasma plays an important role in two ways. First, it increases the phase speed of the fast magnetosonic mode; and second, it causes the breakup of the extraordinary mode dispersion relation in the vicinity of the harmonics, where the broken dispersion curves are connected with multiple ion Bernstein modes. In this case, the waves propagating radially are absorbed at locations where their frequency reaches integer multiples of Ωp and background protons experience perpendicular heating at those locations.
Integrated Orbit Determination of FengYun‐3C, BDS, and GPS Satellites
Authors: Li Xingxing , Zhang Keke , Zhang Qian , Zhang Wei , Yuan Yongqiang , Li Xin
Published: August 2018

Aiming at weather forecast and global climate research, the satellite FengYun‐3C (FY‐3C), as the new generation of China's weather satellites, was launched in 2013. It carries the Global Navigation Satellite Systems Occultation Sounder instrument, a BDS + GPS receiver, to fulfill the demand of orbit determination and occultation. In this contribution, we develop an integrated orbit determination of FY‐3C, BDS, and GPS satellites by joint processing of onboard FY‐3C and ground data during 2013–2017. Four processing schemes, BDS, GPS, BDS + GPS, and BDS (without Geostationary Earth Orbit [GEO]) + GPS, are designed to investigate the capability of BDS for the integrated precise orbit determination and the benefit of BDS and GPS fusion. Regional and global networks are also employed to analyze the influence of station distribution on the orbit determination. The results show that with a regional network, both BDS and GPS orbits present a significant improvement after including FY‐3C data. For the BDS + GPS one‐step solution, GPS orbits are improved by 20% compared with the two‐step solution, while the improvement can reach 42%, 27%, and 27% for BDS GEO, Inclined Geosynchronous Satellite Orbit, and Medium Earth Orbit, respectively. The precision improvement of FY‐3C is respectively 26%, 44%, and 30% in along, cross, and radial components. For a global network, the orbit precision of the BDS + GPS solution is improved by 4% for GPS and 5%, 16%, and 19% for BDS GEO, Inclined Geosynchronous Satellite Orbit, and Medium Earth Orbit, respectively. For FY‐3C, the orbit improvement can reach 7%. The validation with satellite laser ranging also demonstrates the benefit of the integrated orbit determination. Such a high‐quality orbit will potentially benefit meteorological studies and applications.
Lithospheric Structure of Greenland From Ambient Noise and Earthquake Surface Wave Tomography
Authors: Pourpoint Maeva , Anandakrishnan Sridhar , Ammon Charles J. , Alley Richard B.
Published: August 2018

We present a high‐resolution shear wave velocity model of Greenland's lithosphere from regional and teleseismic Rayleigh waves recorded by the Greenland Ice Sheet Monitoring Network supplemented with observations from several temporary seismic deployments. To construct Rayleigh wave group velocity maps, we integrated signals from regional and teleseismic earthquakes with several years of ambient seismic noise and used the dispersion to constrain crustal and upper‐mantle seismic shear wave velocity structure. Specifically, we used a Markov Chain Monte Carlo technique to estimate 3‐D shear wave velocities beneath Greenland to a depth of 200 km. Our model reveals four prominent anomalies: a deep high‐velocity feature extending from southwestern to northwestern Greenland that may be the signature of a thick cratonic keel, a corridor of relatively low upper‐mantle velocity across central Greenland that could be associated with lithospheric modification from the passage of the Iceland plume beneath Greenland or interpreted as a tectonic boundary between cratonic blocks, an upper‐crustal southwest‐northeast trending boundary separating Greenland into two regions of contrasting tectonic and crustal properties, and a midcrustal low‐velocity anomaly beneath northeastern Greenland. The nature of this midcrustal anomaly is of particular interest given that it underlies the onset of the Northeast Greenland Ice Stream and raises interesting questions regarding how deeper processes may impact the ice stream dynamics and the evolution of the Greenland Ice Sheet.
Implications of Eddy Cancellation for Nutrient Distribution Within Subtropical Gyres
Authors: Doddridge Edward W. , Marshall David P.
Published: August 2018

The role of mesoscale eddies within the nutrient budget of subtropical gyres remains poorly understood and poorly constrained. We explore a new mechanism by which mesoscale eddies may contribute to these nutrient budgets, namely eddy cancellation. Eddy cancellation describes the rectified effect of mesoscale eddies acting to oppose the Eulerian‐mean Ekman pumping. We present an idealized axisymmetric two‐layer model of a nutrient in a wind‐driven gyre and explore the sensitivity of this model to variations in its parameter values. We find that the residual Ekman pumping velocity has a substantial impact on nutrient concentration, as does mode water thickness. These results suggest the response to both residual Ekman pumping and mode water thickness is nonmonotonic: for small values of these parameters the nutrient concentration decreases as the parameter increases. However, beyond a critical value, further increases in Ekman pumping or mode water thickness increase nutrient concentration throughout our highly idealized model. A thin mode water layer promotes vertical diffusion of nutrients from the abyss, while a thicker mode water layer increases productivity by reducing the parametrized particulate flux through the thermocline. The impact of mode water thickness is modulated by the residual Ekman pumping velocity: strong Ekman pumping suppresses the influence of mode water thickness on nutrient concentrations. We use satellite and in situ measurements to assess the influence of mode water thickness on primary productivity and find a statistically significant relationship; thicker mode water correlates with higher productivity. This result is consistent with a small residual Ekman pumping velocity.
Drivers of Ice Algal Bloom Variability Between 1980 and 2015 in the Chukchi Sea
Authors: Selz Virginia , Saenz Benjamin T. , van Dijken Gert L. , Arrigo Kevin R.
Published: August 2018

Sea ice provides an important habitat for the ice algae that fuel upper trophic levels in early spring, prior to phytoplankton bloom development. In the Chukchi Sea, the ice environment has experienced large‐scale changes in snow cover, ice thickness and extent, and timing of ice advance and retreat. Using a 1‐D coupled physical‐biological ice‐ecosystem model and observed distributions of sea ice, we investigated how changing ice conditions may have impacted ice algal bloom dynamics for the central Chukchi Sea between 1980 and 2015. Model results suggest that over this 35‐year time period, annual ice algal net primary production (NPP) decreased by 22%. Modeled snow and ice melt, as well as satellite‐derived ice retreat, occurred progressively earlier in the spring from 1980 to 2015, even though modeled ice and snow thicknesses showed no temporal trends. Over time, ice algal blooms ended earlier in spring due to earlier onset of ice melt and ice retreat. Results suggest that the length of the ice season sets the upper bound on annual ice algal NPP, with late melt years corresponding to highest NPP. Linear regression results suggest that within early versus late melt year groupings, snow plays a secondary, yet important role in determining annual ice algal NPP. As sea ice thins and melts earlier in spring, future snow dynamics will be an important factor determining the onset of the ice algal bloom and thus the duration of the bloom in an early melt, shortened ice season scenario.
Tracing the Three Atlantic Branches Entering the Arctic Ocean With 129I and 236U
Authors: Casacuberta N. , Christl M. , Vockenhuber C. , Wefing A.‐M. , Wacker L. , Masqué P. , Synal H.‐A. , Rutgers van der Loeff M.
Published: August 2018

This study presents the data on 129I and 236U concentrations in seawater samples and sea ice cores obtained during two expeditions to the Arctic Ocean that took place onboard R/V Polarstern (PS94) and R/V Lance (N‐ICE2015) in summer 2015. Carbon‐14 was also measured in the deep water samples from the Nansen, Amundsen, and Makarov Basins. The main goal was to investigate the distribution of 129I and 236U in a transect from the Norwegian Coast to the Makarov Basin to fully exploit the potential of combining 129I and 236U as a dual tracer to track Atlantic waters throughout the Arctic Ocean. The use of the 129I/236U and 236U/238U atom ratios allowed identifying a third Atlantic branch that enters the Arctic Ocean (the Arctic Shelf Break Branch) following the Norwegian Coastal Current that carries a larger proportion of the European reprocessing plants signal compared to Fram Strait Branch Water and Barents Sea Branch Water. The combination of 129I and 236U also allowed quantifying the different proportions of the La Hague stream, the Scottish stream, and Atlantic waters forming the three Atlantic branches of the Arctic Ocean Boundary Current. The results show that the 129I/236U atom ratio can now be used to identify the different Atlantic branches entering the Arctic Ocean. New input functions for 129I, 236U, and 129I/236U have also been described for each branch, which can be further used for calculation of transit time distributions of Atlantic waters.
A Comparison of Cloud Microphysical Properties Derived From MODIS and CALIPSO With In Situ Measurements Over the Wintertime Southern Ocean
Authors: Ahn Eunmi , Huang Yi , Siems Steven T. , Manton Michael J.
Published: August 2018

In situ observations of cloud effective radius (reff), droplet number concentration (Nd), and thermodynamic phase from 11 wintertime flights over the Southern Ocean (43–45°S, 145–148°E) are compared to products from MODerate‐resolution Imaging Spectroradiometer (MODIS) and Cloud‐Aerosol Lidar with Orthogonal Polarization. The in situ observations were in close alignment with A‐train overpasses for a 30‐min window. For open mesoscale cellular convection, which was predominantly observed, clouds were commonly found to be intermittently drizzling, patchy, and mixed phase. Compared to the in situ observations of the cloud thermodynamic phase, the Cloud‐Aerosol Lidar with Orthogonal Polarization and MODIS cloud phase optical property products consistently underestimated the occurrence of mixed‐phase clouds, whereas the MODIS infrared‐based phase product showed a better qualitative agreement despite a frequent classification of uncertainty. The MODIS reff_2.1 overestimated the in situ reff for nondrizzling clouds (by ~13 μm on average) and, to a lesser extent, for lightly drizzling cases. Conversely, MODIS reff_2.1 underestimated the in situ reff for heavily drizzling cases by ~10 μm on average. The overestimation of reff is much greater than that for the stratocumulus over the Southeast Pacific shown in other studies. An examination on subpixel heterogeneity, droplet size variability, a bimodal distribution, and solar zenith angle suggests that all of these factors have measurable impacts on the MODIS reff bias. The MODIS Nd is largely consistent with the in situ observations. However, the Nd of the two high Nd cases (closed mesoscale cellular convection) are highly underestimated. An error analysis suggests that the Nd biases are likely a result of a compensating error effect.
Investigating Sources of Mercury's Crustal Magnetic Field: Further Mapping of MESSENGER Magnetometer Data
Authors: Hood L. L. , Oliveira J. S. , Galluzzi V. , Rothery D. A.
Published: August 2018

One hundred six low‐altitude passes of magnetometer data from the last 2 months of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging mission have been applied to produce a map of the crustal magnetic field at a constant altitude of 40 km covering latitudes of 35–75∘ N and longitudes of 270–90∘ E. Some anomalies correlate significantly with impact basins/craters (e.g., Rustaveli and Vyasa), while other basins/craters have no obvious anomalies. A possible interpretation that is consistent with lunar evidence is that some impactors delivered more ferromagnetic Fe–Ni metal to the interior subsurfaces and ejecta fields of the craters/basins that they produced. The amount of metallic iron that could plausibly be delivered is limited by the diameter and mass of an impactor that would yield a crater with observed diameters (e.g., 200 km for Rustaveli). This in turn limits the maximum amplitude of anomalies that could be induced by impactor‐added iron in the present‐day Mercury global field to relatively low values. It is therefore concluded that if impactor‐added iron is the source of the observed crater‐associated anomalies, then they must be almost entirely a consequence of ancient remanent magnetization. A broad magnetic anomaly occurs over the northern rise, a topographically high region with an associated strong free air gravity anomaly. A possible interpretation of the latter anomaly is that an early major impact preconditioned the region for a later mantle uplift event.
Episodic and Declining Fluvial Processes in Southwest Melas Chasma, Valles Marineris, Mars
Authors: Davis J. M. , Grindrod P. M. , Fawdon P. , Williams R. M. E. , Gupta S. , Balme M.
Published: August 2018

There is abundant evidence for aqueous processes on Noachian terrains across Mars; however, key questions remain about whether these processes continued into the Hesperian as the martian climate became less temperate. One region with an extensive Hesperian sedimentary record is Valles Marineris. We use high‐resolution image and topographic data sets to investigate the fluvial systems in the southwest Melas basin, Valles Marineris, Mars. Fluvial landforms in the basin exist across a wide area, and some are preserved as inverted channels. The stratigraphy of the basin is complex: Fluvial landforms are preserved as planview geomorphic features and are also interbedded with layered deposits in the basin. The fluvial morphologies are consistent with formation by precipitation‐driven runoff. Fluvial processes in the basin were episodic, suggesting multiple wet and dry periods. During dry periods, mantling material accumulated, and significant volumes of sediment were eroded, inverting fluvial channels. During wet periods, inverted channels and mantling material infilling valleys were incised by further fluvial erosion. These trends for episodic fluvial processes are similarly reflected in the central depression of the southwest Melas basin, previously described as a paleolake. Ultimately, fluvial processes in the basin gradually shut down, becoming geographically restricted, and then ceased entirely. We show that branching valley networks are also present on the plateaus above Melas and Ius Chasma, which converge on the heads of tributary canyons. These suggest that precipitation‐driven runoff processes also extended onto the plateaus of Valles Marineris.
Hydrologic and Edaphic Controls on Soil Carbon Emission in Dongting Lake Floodplain, China
Authors: Deng Zhengmiao , Li Youzhi , Xie Yonghong , Peng Changhui , Chen Xinsheng , Li Feng , Ren Yijie , Pan Baihan , Zhang Chengyi
Published: August 2018

Wetlands play a critical role in mitigating carbon emission. However, little is known about soil carbon emission and their environmental controls from inland floodplain wetlands. This study aimed to determine the effects of hydrologic and edaphic controllers (water table depth [WTD], soil temperature [Ts], and soil water content [SWC]) on soil C emission in Dongting Lake wetland, China. One‐year emissions were measured in Carex meadow and mudflat using static chambers during 2013 to 2014, including nonflooded season (NFs) and flooded season (Fs). The results showed that soil C emission in the Carex meadow and mudflat was 307.8 and 264.3 g C·m−2·year−1, respectively, and 50–66% of soil C were emitted during NFs. Compared with NFs, CO2 emission was significantly decreased by 57% but CH4 emission was significantly increased by 38 times during Fs in the Carex meadow. Stepwise regression combined with structural equation model analysis showed that CO2 and CH4 flux were mainly influenced by Ts during NFs, and they were controlled by water temperature (Tw) during Fs. During NFs, CO2 flux increased with increasing Ts and SWC but decreased significantly when SWC was over 66% and 52% in the Carex meadow and mudflat, respectively. CH4 flux showed an emission pulse at SWC and Ts of 65% and 17.2 °C, respectively. These results indicate that flooding significantly inhibited soil CO2 emission but stimulated CH4 emission. The continuous decrease of flooding days caused by anthropogenic disturbances may induce soil C loss in Dongting Lake wetlands.
Partitioning Eddy Covariance Water Flux Components Using Physiological and Micrometeorological Approaches
Authors: Perez‐Priego Oscar , Katul Gabriel , Reichstein Markus , El‐Madany Tarek S. , Ahrens Bernhard , Carrara Arnaud , Scanlon Todd M. , Migliavacca Mirco
Published: August 2018

Eddy covariance (EC) provides ecosystem‐scale estimates of photosynthesis (Ph) and evapotranspiration (ET; the sum of plant transpiration [T] and evaporation [Es]). Separating ET into its components is becoming necessary for linking plant‐water use strategies to environmental variability. Based on optimality principles, a data‐model based approach for partitioning ET was proposed and independently tested. Short‐term responses of canopy‐scale internal leaf‐to‐ambient CO2 (χ) were predicted based on a big‐leaf representation of the canopy accounting for the influence of boundary‐layer conductance. This representation allowed investigating stomatal behavior in accordance with the Ph estimates. With the objective of minimizing the carbon cost of transpiration, a novel optimization approach was implemented to develop solutions for an optimal stomatal conductance model as the basis to derive T. The Es was then calculated as a residual between the observed ET and modeled T. The proposed method was applied to long‐term EC measurements collected above a Mediterranean tree‐grass ecosystem. Estimated Es agreed with independent lysimeter measurements (r = 0.69). They also agreed with other partitioning methods derived from similarity theory and conditional sampling applied to turbulence measurements. These similarity schemes appeared to be sensitive to different χ parameterization. Measured Es was underestimated by 30% when χ was assumed constant (= 0.8). Diel and seasonal χ patterns were characterized in response to soil dryness. A surprising result was a large Es/ET throughout the seasons. The robustness of the results provides a new perspective on EC ET partitioning, which can be utilized across a wide range of climates and biomes.
Multiyear Trends in Solute Concentrations and Fluxes From a Suburban Watershed: Evaluating Effects of 100‐Year Flood Events
Authors: Coble Ashley A. , Wymore Adam S. , Shattuck Michelle D. , Potter Jody D. , McDowell William H.
Published: August 2018

Anthropogenic activities have increased solute concentrations and fluxes in rivers globally. Increases in salt, dissolved organic carbon, and inorganic nutrients have been attributed to changes in atmospheric deposition, road salt and fertilizer application, and urbanization. Extremely large flood events, which are increasing in frequency and duration, could also alter river chemistry by flushing various solute reservoirs within watersheds and effectively “resetting” the linkages between land and river. We evaluated changes in concentrations and fluxes of inorganic nutrients, dissolved organic matter, and salts and major ions across 12 to 15 years in a rural‐suburban watershed in New Hampshire, USA. During this period, the human imprint on the landscape (impervious surfaces and population density) increased, but two 100‐year flood events also occurred. We found that concentrations and fluxes of chloride and potassium, fluxes of all other major ions, and concentrations of dissolved organic carbon declined over time, but concentrations and fluxes of inorganic nutrients and dissolved organic nitrogen were unchanged. The minor declines in concentrations were of similar magnitude to declines previously observed in other watersheds that did not experience extreme flood events. We observed a shift in nitrate (NO3−) concentration‐discharge behavior from enrichment in the years prior to and including the floods to chemostasis after the floods, but for both time periods NO3− concentrations were weakly related to discharge. Our results suggest a limited role of extreme events in the biogeochemistry of urbanizing watersheds and emphasize the importance of long‐term records and multiple analytical approaches to understand the dynamics of complex watersheds.
Incorporation of Microbial Functional Traits in Biogeochemistry Models Provides Better Estimations of Benthic Denitrification and Anammox Rates in Coastal Oceans
Authors: Zhang Xiaoli , Zhang Qianqian , Yang Anjing , Hou Lijun , Zheng Yanling , Zhai Weidong , Gong Jun
Published: August 2018

Marine benthic nitrogen (N) cycling may vary widely across space and seasons; it is thus needed to make high‐resolution estimations of these important ecosystem processes with a reasonable number of variables. In this study, we determined the benthic denitrification and anammox potentials in two basins, the Bohai Sea and the North Yellow Sea of China in May and November, and evaluated models in predicting these functions with environmental factors and/or microbial gene‐based functional traits. We found that denitrification generally dominated the N loss (54–98%), and that the denitrification rate varied greatly between basins and seasons. The anammox rate was generally higher in the Bohai Sea than in the North Yellow Sea in both seasons, and it made a greater contribution in November (22%) than in May (16%). Among the measured environmental factors, chlorophyll a in bottom waters and sedimentary organic carbon content were the most influential for predicting denitrification and anammox rates, respectively. On the other hand, the alpha diversities and gene abundances of involved bacteria were poorly correlated with the function potentials, indicating that these functional traits could not well explain the functions alone. Upon the incorporation of two gene copy number ratios [nosZ/(nirS + nirK) and nirK/bacterial 16S rRNA genes] into the environmental factor‐parameterized models, however, we found that the predictive powers of the regression models for total N loss, denitrification and anammox rates, and contributions of anammox increased substantially, indicating that taking microbial functional traits into account could make estimations of these N‐cycling functions in coastal ecosystems more accurate.
Space Weather on the Surface of Mars: Impact of the September 2017 Events
Authors: Hassler D. M. , Zeitlin C. , Ehresmann B. , Wimmer‐Schweingruber R. F. , Guo J. , Matthiä D. , Rafkin S. , Berger T. , Reitz G.
Published: August 2018

Although solar activity is declining as the Sun approaches solar minimum, a series of large solar storms occurred in September 2017 that impacted both Earth and Mars. This was the largest event seen on the surface of Mars by the Radiation Assessment Detector on the Mars Science Laboratory Curiosity rover since landing in 2012 and was also observed as Ground Level Enhancement 72 on Earth, making it the first event observed to produce a Ground Level Enhancement on two planets at the same time. We present Radiation Assessment Detector observations of the surface radiation environment since 2012 and discuss the impact of the September 2017 events on this environment and its implications for human exploration and for mitigating the risk of space radiation and space weather events for future manned missions to Mars.
RNA-binding protein LIN28B inhibits apoptosis through regulation of the AKT2/FOXO3A/BIM axis in ovarian cancer cells
Authors: Lin Xiaojuan , Shen Jianfeng , Dan Peng  , He Xinhong , Xu Congjian , Chen Xiaojun , Tanyi Janos L. , Montone Kathleen , Fan Yi , Huang Qihong , Zhang Lin , Zhong Xiaomin
Published: August 2018

LIN28B is an evolutionarily conserved RNA-binding protein that regulates mRNA translation and miRNA let-7 maturation in embryonic stem cells and developing tissues. Increasing evidence demonstrates that LIN28B is activated in cancer and serves as a critical oncogene. However, the underlying molecular mechanisms of LIN28B function in tumorigenesis are still largely unknown. Here we report that LIN28B was expressed in over half of the patients with epithelial ovarian cancer who were examined (n = 584). Functional experiments demonstrated that LIN28B inhibited ovarian cancer cell apoptosis. Furthermore, we showed that the proapoptotic factor BIM played an essential role in the antiapoptotic function of LIN28B. RNA-IP microarray analysis suggested that LIN28B binds to mRNAs that are associated with the DNA damage pathway, such as AKT2, in ovarian cancer cells. By binding to AKT2 mRNA and enhancing its protein expression, LIN28B regulated FOXO3A protein phosphorylation and decreased the transcriptional level of BIM, which antagonized the antiapoptosis activity of LIN28B. Taken together, these results mechanistically linked LIN28B and the AKT2/FOXO3A/BIM axis to the apoptosis pathway. The findings may have important implications in the diagnosis and therapeutics of ovarian cancer.
Runx-dependent and silencer-independent repression of a maturation enhancer in the Cd4 gene
Authors: Kojo Satoshi , Yasmin Nighat , Muroi Sawako , Tenno Mari , Taniuchi Ichiro
Published: August 2018

An intronic silencer, S4, in the Cd4 gene has been shown to be responsible for the helper-lineage-specific expression of CD4; S4 requires Runx complex binding to exert its silencer function against the enhancer-mediated Cd4 activation by modulating the epigenetic state of the Cd4 gene. Here we identify a late-acting maturation enhancer. Bcl11b plays essential roles for activation of both the early-acting proximal enhancer and maturation enhancer of Cd4. Notably, Runx complexes suppress these enhancers by distinct mechanisms. Whereas repression of the proximal enhancer depends on the S4 silencer, the maturation enhancer is repressed by Runx in the absence of S4. Moreover, ThPOK, known to antagonize S4-mediated Cd4 repression, assists Runx complexes to restrain maturation enhancer activation. Distinct modes of S4 silencer action upon distinct enhancers thus unravel a pathway that restricts CD4 expression to helper-lineage cells by silencer-independent and Runx-dependent repression of maturation enhancer activity in cytotoxic-lineage cells.