bluuebunny/crossref_metadata_2025 huggingface dataset:
Sporopollenin as a dilution agent in artificial diets for solitary bees
Authors: Tainsh Fiona , Woodmansey Shannon R. , Austin Alexander J. , Bagnall Toby E. , Gilbert James D. J.
Published: October 2020

Nutritional studies often require precise control of nutrients via dilution of artificial diets with indigestible material, but such studies in bees are limited. Common diluents like cellulose typically result in total mortality of bee larvae, making quantitative studies difficult. We investigated potential alternative dietary dilution agents, sporopollenin (pollen exines) and agar. We rearedOsmia bicornislarvae on pollen diluted with these substances, alongside undiluted controls. Sporopollenin neither prevented nor improved survival, suggesting it is a suitable diluent. Agar appeared marginally to increase survival and its suitability requires further research. Both substances reduced cocoon weight, and sporopollenin also prolonged development, suggesting processing costs. Determining the physiological mechanisms driving these responses requires further work. Our findings should facilitate studies involving nutritional manipulations for solitary bees.
Halpern–Ishikawa type iterative schemes for approximating fixed points of multi-valued non-self mappings
Authors: Tufa Abebe R. , Thuto M. , Moetele M.
Published: September 2020

Let C be a nonempty closed convex subset of a real Hilbert space H and $$T: C\rightarrow CB(H)$$

T
:
C
→
C
B
(
H
)

be a multi-valued Lipschitz pseudocontractive nonself mapping. A Halpern–Ishikawa type iterative scheme is constructed and a strong convergence result of this scheme to a fixed point of T is proved under appropriate conditions. Moreover, an iterative method for approximating a fixed point of a k-strictly pseudocontractive mapping $$T: C\rightarrow Prox(H)$$

T
:
C
→
P
r
o
x
(
H
)

is constructed and a strong convergence of the method is obtained without end point condition. The results obtained in this paper improve and extend known results in the literature.
Digitization of neuropsychological diagnostics: a pilot study to compare three paper-based and digitized cognitive assessments
Authors: Latendorf Antje , Runde Lina Marie , Salminen Tiina , Steinert Anika
Published: October 2020

Background and objective

The number of people suffering from dementia is increasing worldwide and so is the need for reliable and economical diagnostic instruments. Therefore, the aim of this study was to compare the processing times of the neuropsychological tests Trail Making Tests A and B (TMT-A/B) and Color-Word Interference Test (CWIT), which were performed in both digital and paper versions.

Methods

The pilot study was conducted among 50 healthy participants (age 65–83 years) using a randomized crossover design. The correlations and differences in the individual processing times of the two test versions were statistically analyzed. Further research questions concerned the influence of the individual usage of technology and the technology commitment of participants as well as the influence of the assessed usability on participants’ performance.

Results

Between the two versions (paper-based vs. digital) statistically significant correlations were found in all tests, e.g., TMT-A r(48) = 0.63, p < 0.01; TMT-B rs(48) = 0.77, p < 0.001). The mean value comparison showed statistically significant differences, e.g., interference table (CWIT) t(49) = 11.24, p < 0.01). Correlations with medium effect were found between the differences in processing times and the individual usage of computer (e.g., rs(48) = − 0.31) and smartphone (rs(48) =  − 0.29) and between the processing times of the TMT-B and the usability (rs(48) = 0.29).

Conclusions

The high correlations between the test procedures appear promising. However, the differences found in the processing times of the two test versions require validation and standardization of digitized test procedures before they can be used in practice.
Multidimensional Prognostic Index (MPI) in elderly patients with acute myocardial infarction
Authors: Cammalleri Valeria , Bonanni Michela , Bueti Francesca Maria , Matteucci Andrea , Cammalleri Lisa , Stifano Giuseppe , Muscoli Saverio , Romeo Francesco
Published: October 2020

Background

Management of elderly patients with acute myocardial infarction (AMI) is challenging due to lack of knowledge about the link between fragility, outcomes and interventional procedures.

Aims

The aim of this study was to establish the prognostic role of the Multidimensional Prognostic Index (MPI) in elderly with AMI.

Methods

A total of 241 patients ≥ 65 years old with AMI were continuously enrolled in this prospective study and divided into three groups according to the MPI score. The primary endpoint was 30-day mortality. Secondary endpoints were 6-month mortality and rate of adverse events.

Results

In-hospital overall mortality rate was higher in MPI-3 (p = 0.009). Patients of MPI-3 had a significantly higher mortality rate regarding the primary endpoint with 30-day survival of 78.9%, compared to 97.4% and 97.2%, in MPI-1, MPI-2 (p < 0.001), respectively. The survival rate progressively decreased in the three MPI classes of risk with a 6-month survival of 96.5%, 96.3%, 73.7% in groups MPI-1, MPI-2, and MPI-3 (p < 0.001). Longer length of in-hospital stay was observed in MPI-3 group. In-hospital complications were more frequent in higher MPI score.

Discussion

Our findings are in agreement with the results of other studies that evaluated the risk of in-hospital complications and mortality in older patients. In our “real-world” population of elderly hospitalized for AMI we observed poorer outcomes in patients belonged to higher MPI groups.

Conclusions

In the setting of AMI, MPI may be very useful in the daily clinical practice to manage older patients and predict the risk of in-hospital and follow-up complications.
Nutrition Transition and Climate Risks in Nigeria: Moving Towards Food Systems Policy Coherence
Authors: Morgan Alexandra E. , Fanzo Jessica
Published: October 2020

Purpose of Review

The purpose of this review is to describe the combined impacts of the nutrition transition and climate change in Nigeria and analyze the country’s national food-related policy options that could support human and planetary health outcomes.

Recent Findings

This paper uses a food systems framework to analyze how the nutrition transition and climate change interact in Nigeria affecting both diets and the double burden of malnutrition, resulting in what has been termed the syndemic. Interactions between climate change and the nutrition transition in Nigeria are exacerbating diet-related inequities and will continue to do so if food systems continue on their current trajectory and without significant transformation. Siloed policy actions that attempt to mitigate one aspect of food system risk can create a negative feedback loop in another aspect of the food system. Our analysis finds that Nigeria has five national policies that include actionable steps to address food system insufficiencies; however, each of these policies is constrained by the boundaries of singular nutrition, climate change, and agricultural objectives. The country should consider a coherent policy environment that explicitly identifies and links underlying systemic and institutional drivers between climate change and malnutrition that simultaneously and comprehensively address both human and planetary health outcomes of food systems.

The systemic and institutional outcomes of this emerging syndemic—undernutrition, obesity, and climate change—are inexorably linked. Nigeria lacks a coherent policy environment taking on this challenging syndemic landscape. The analysis in this paper highlights the need for Nigeria to prioritize their national nutrition and agricultural and climate policies that uncouple feedback loops within food systems to address climate change and malnutrition in all its forms.
Quarantined, Sequestered, Closed: Theorising Academic Bodies Under Covid-19 Lockdown
Authors: Gourlay Lesley
Published: October 2020

The term ‘quarantine’ is derived from the Italian quarantena, from quaranta, referring to the forty days of isolation traditionally imposed during the era of the Black Death in Europe. This paper examines this and related contemporary terms, in order to consider the complex and contradictory nature of enforced sites of isolation, with reference to the historical literature. The centrality of spatial practices in the current pandemic is emphasised, with a focus on the normally unobserved, micro practices of individuals under ‘lockdown’. The paper reports on an interview study conducted at a large UK Higher Education institution during the Covid-19 ‘lockdown’, and analyses the accounts of six academics, focusing particularly on their embodied and sociomaterial practices, with reference to the etymological analysis. The paper considers the extent to which their reported experiences reflect the various meanings of the term sequestrato, going on to propose that their working practices, particularly focused on screens and video calls, are characterised by a need to ‘perform the university’. I speculate on how the ontological nature of the university itself has been fundamentally altered by the closure of the campus and lockdown, proposing that the site of the university is now radically dispersed across these sequestered bodies. I conclude by calling into the question the accuracy of the term ‘online teaching and learning’, instead suggesting that in a fundamental sense, none of these practices is in fact ‘online’ or digital.
Transformation of Magnesite to Sepiolite and Stevensite: Characteristics and Genesis (Çayirbaği, Konya, Turkey)
Authors: Yeniyol Mefail
Published: September 2020

Çayırbağı magnesite is one of numerous magnesite deposits occurring throughout Turkey. In this deposit, sepiolite and newly found stevensite occur locally as two daughter minerals formed from magnesite. The sepiolite and stevensite show distinctive compositions and modes of formation compared to those described in the literature. The objective of the current study was to characterize these minerals by means of mineralogic, thermal, structural, geochemical, and textural analyses and to describe their mechanisms of formation. The geology, mineralogy, and geochemistry were examined by field work followed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential thermal (DTA), and thermogravimetric (TG) analyses. Chemical analyses were performed by means of electron microprobe (EMPA), inductively coupled plasma-optical emission spectrometry (ICP-OES), and laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS). The XRD analyses showed that the d110 of the sepiolite was at 12.64 Å and at 13 Å after air-drying and ethylene-glycol solvation, respectively. Identification of the sepiolite as sepiolite-13 Å was supported by FTIR and TG-DTA data. Chemical analyses showed an ideal composition with a structural formula of (Ca0.05K0.02)(Mg7.79Al0.10□0.11)Si12O30(OH)4. Stevensite displayed distinctive results for XRD, FTIR, and thermal characteristics. The structural formula of stevensite was: (Ca0.01Na0.20K0.04)(Mg1.90Al0.30Fe3+0.37Ti0.01□0.43)(Si3.93Al0.07)O10(OH)2, indicating a layer charge arising mainly from octahedral sheets. Field and SEM observations demonstrated that sepiolite was formed from magnesite by transformation via a dissolution–precipitation mechanism. Descending surface waters were responsible for this transformation. Thick magnesite veins were partly replaced whereas in thin veins sepiolite replaced the overall mass. Both surface waters with high Si, low Al and Fe activities, and pH values of 8–9.5 were responsible for sepiolite formation. Stevensite was formed similarly to sepiolite with respect to the mechanism and parent mineral under permanent groundwater; where both Si, Fe, Al activities and pH (>9.5) were high.
The role of social support in differentiating trajectories of adolescent depressed mood
Authors: Gregory Danica , Turnbull Deborah , Bednarz Jana , Gregory Tess
Published: September 2020

Introduction

This study explored the extent to which disaggregated support from family, peers, close friendships, teachers, and schools predicted membership into identified, sex‐specific trajectories of depressed mood in 3210 Australian adolescents (49% females) based on self‐report data collected at four annual time points from school Grade 6 to 9 (ages 10–16).

Methods

The sample was initially split by sex. Group‐Based Trajectory Modelling was used to identify the trajectory groups using a Censored Normal model, starting with a two‐group model and increasing group size in increments of one, up to a six‐group model. Overall model‐fit and specific model‐fit criteria were examined, and participants were allocated to best‐fit groups. Multinomial Logistic Regression examined the associations between baseline social supports and allocated trajectory group membership.

Results

For boys, four trajectory groups were identified which were given the qualitative labels; Low Stable, Moderate Stable, Moderate Decreasing, and High Stable. Regression analysis showed that higher rates of peer belonging were associated with membership in the low and moderate groups compared to the High Stable group. For girls, four trajectory groups were identified and labelled as Low Stable, Moderate Decreasing, Moderate Increasing and High Increasing. Regression analysis showed that higher rates of family support, school climate, and peer belonging were associated with membership in the low and moderate groups compared to the High Increasing group.

Conclusions

Implications included the need for school‐based early intervention programs to consider disaggregated supports and vary their interventions by sex. Limitations and directions for future research are discussed.
Genetic Variation in the Androgen Receptor Modifies the Association Between Testosterone and Vitality in Middle-Aged Men
Authors: Panizzon Matthew S. , Bree Kelly , Hsieh Tung-Chin , Hauger Richard , Xian Hong , Jacobson Kristen , Lyons Michael J. , Franz Carol E.
Published: October 2020

Background

Low vitality is a common symptom of testosterone deficiency; however, clinical trial results remain inconclusive regarding the responsiveness of this symptom to hormone replacement.

Aim

The aim of the present study was to determine if the relationship between circulating testosterone levels and vitality would be moderated by the CAG repeat length in the androgen receptor (AR) gene, which influences the receptor’s sensitivity to testosterone.

Methods

We examined 676 men in the Vietnam Era Twin Study of Aging when they were, on average, 55.4 years old (SD = 2.5). Salivary testosterone levels were measured by using 3 samples collected at waking on 3 nonconsecutive days. The average testosterone level was classified as low, normal, or high based on 1-SD cutoffs. Analyses were conducted using multilevel, mixed linear models, which accounted for the nonindependence of the twin data, and adjusted for the effects of age, ethnicity, BMI, chronic health conditions, depressive symptoms, and sleep quality.

Outcomes

Vitality was measured using the 36-item Short Form (SF-36) vitality subscale.

Results

We observed a significant interaction between salivary testosterone and the AR-CAG repeat length. When the repeat length was short, men with low testosterone had significantly lower vitality. As the AR-CAG repeat length increased, the magnitude of the testosterone effect decreased.

Clinical Translation

The observed interaction between testosterone and variation in the AR gene suggests that men with more sensitive ARs, as indicated by a shorter AR-CAG repeat, are more likely to experience symptoms of age-related testosterone deficiency.

Strengths & Limitations

Strengths of the present study include our use of a large community-based sample, the use of multiple testosterone measurements, and the availability of a comprehensive set of covariates that may impact the association of interest. Limitations include the homogeneous nature of the sample with respect to ethnicity, the brevity of the 36-item Short Form vitality subscale, and our inability to establish change in testosterone levels because of the cross-sectional nature of data.

Conclusions

The association between testosterone and vitality appears to be clinically meaningful and is in part dependent on variation in the AR gene.
Wrongful ways to raise the epistemic standard
Authors: Grindrod Jumbly
Published: October 2020

This paper is concerned with identifying and accounting for cases where the epistemic standard is raised inappropriately. The first section is concerned with identifying a notion of a variable epistemic standard that is neutral regarding a range of theoretical issues. The second section argues that the possibility the epistemic standard could be raised in some epistemic inappropriate way warrants further investigation. The third section outlines and provides a partial explanation of such a case: one in which a climate change denier attempts to raise the epistemic standard in order to shut down inquiry.
COVID-19 and its effect on emergency presentations to a tertiary hospital with self-harm in Ireland
Authors: McIntyre A. , Tong K. , McMahon E. , Doherty A. M.
Published: September 2020

Objectives:

This study aimed to assess the impact of COVID-19 on presentations to an acute hospital with self-harm.

Methods:

All presentations to University Hospital Galway with self-harm were assessed during the peak period of the coronavirus crisis in Ireland, over the 3 months from 1 March to 31 May 2020. These data were compared with presentations in the same months in the 3 years preceding (2017–2019). Data were obtained from the anonymised service database.

Results:

This study found that in 2020, the rate of presentation with self-harm dropped by 35% from March to April and rose by 104% from April to May, peaking from mid-May. When trends over a 4-year period were examined, there was a significantly higher lethality of attempt (p< 0.001), and significant differences in diagnosis (p= 0.031) in 2020 in comparison with the three previous years. The increased lethality of presentations remained significant after age and gender were controlled for (p= 0.036). There were also significant differences in the underlying psychiatric diagnoses (p= 0.018), notably with a significant increase in substance misuse disorders presenting during the 2020 study period.

Conclusions:

COVID-19 showed a reduction in self-harm presentations initially, followed by a sharp increase in May 2020. If a period of economic instability follows as predicted, it is likely that this will further impact the mental health of the population, along with rates of self-harm and suicidal behaviours. There is a need for research into the longer-term effect of COVID-19 and lockdown restrictions, especially with respect to self-harm.
Characterization of snowfall estimated by in situ and ground-based remote-sensing observations at Terra Nova Bay, Victoria Land, Antarctica
Authors: Scarchilli Claudio , Ciardini Virginia , Grigioni Paolo , Iaccarino Antonio , De Silvestri Lorenzo , Proposito Marco , Dolci Stefano , Camporeale Giuseppe , Schioppo Riccardo , Antonelli Adriano , Baldini Luca , Roberto Nicoletta , Argentini Stefania , Bracci Alessandro , Frezzotti Massimo
Published: October 2020

Knowledge of the precipitation contribution to the Antarctic surface mass balance is essential for defining the ice-sheet contribution to sea-level rise. Observations of precipitation are sparse over Antarctica, due to harsh environmental conditions. Precipitation during the summer months (November–December–January) on four expeditions, 2015–16, 2016–17, 2017–18 and 2018–19, in the Terra Nova Bay area, were monitored using a vertically pointing radar, disdrometer, snow gauge, radiosounding and an automatic weather station installed at the Italian Mario Zucchelli Station. The relationship between radar reflectivity and precipitation rate at the site can be estimated using these instruments jointly. The error in calculated precipitation is up to 40%, mostly dependent on reflectivity variability and disdrometer inability to define the real particle fall velocity. Mean derived summer precipitation is ~55 mm water equivalent but with a large variability. During collocated measurements in 2018–19, corrected snow gauge amounts agree with those derived from the relationship, within the estimated errors. European Centre for the Medium-Range Weather Forecasts (ECMWF) and the Antarctic Mesoscale Prediction System (AMPS) analysis and operational outputs are able to forecast the precipitation timing but do not adequately reproduce quantities during the most intense events, with overestimation for ECMWF and underestimation for AMPS.
Childhood Abuse and Positive and Negative Relationship Quality in Women: The Role of Depression
Authors: Fitzgerald Michael , Ledermann Thomas , Grzywacz Joseph G. , Hamstra Cailyn
Published: September 2020

The interpersonal nature of childhood abuse has led researchers to examine how abuse in childhood is associated with the quality of adult women's romantic relationships. Depression is one pathway by which childhood abuse may be associated with relationship quality. The current study considers whether childhood abuse is linked to positive and negative relationship quality through depressive symptoms. Data were obtained from women participating in the Longitudinal Study of Childhood Abuse and Neglect (LONGSCAN; N = 544) and were analysed using structural equation modelling. Results indicate a significant indirect effect from childhood abuse to both positive and negative quality through women's depressive symptoms. The indirect effect from abuse to negative relationship quality through depression was significantly larger than positive relationship quality. These results suggest that childhood abuse and subsequent depressive symptoms has a twofold effect on women's romantic relationships.
The place of Edward Gresham'sAstrostereon(1603) in the discussion on cosmology and the Bible in the early modern period
Authors: BIENIAS BARBARA
Published: October 2020

This article situates Edward Gresham'sAstrostereon, or A Discourse of the Falling of the Planet(1603), a little-known English astronomical treatise, in the context of the cosmo-theological debate on the reconciliation of heliocentrism with the Bible, triggered by the publication of Nicholas Copernicus'sDe revolutionibus orbium coelestiumin 1543. Covering the period from the appearance of the ‘First Account’ of Copernican views presented in Georg Joachim Rheticus'sNarratio Prima(1540) to the composition ofAstrostereonin 1603, this paper places Edward Gresham's commentary and exegesis against the background of the views expressed by his countrymen and the thinkers associated with the Wittenberg University – such as Philipp Melanchthon, Caspar Peucer, and Christoph Rothmann. Comparing the ways in which they employed certain biblical passages – either in favour of or against the Earth's mobility – the paper emphasizes Gresham's ingenious reading of the Hebrew version of the problematic excerpts, and his expansion of the accommodation principle.
Snail-borne zoonotic trematodes in edible viviparid snails obtained from wet markets in Northern Thailand
Authors: Chantima K. , Rika C.
Published: October 2020

Edible viviparid snails are suspected to be the source of human echinostomiasis in Thailand, but little is known about the prevalence of viviparid snail parasitization by echinostomes in snails sold for human consumption in wet markets. Here, the prevalence of echinostome metacercariae and the association between parasitic intensity and host size, as well as the relationship to host species, were investigated. In total, 1100 viviparid snails belonging to four species (Cipangopaludina annandalei, Filopaludina martensi martensi, F. sumatrensis polygramma and F. doliaris) were obtained from wet markets in Chiang Rai Province, Northern Thailand. All snail species were found to be infected with echinostome metacercariae with total prevalence and mean intensity values of 16.5% and 16.4, respectively. The metacercariae of the avian trematode, Thapariella anastomusa were found in Filopaludina spp. snails. Interestingly, C. annandalei identified in this study had not previously been considered a food source and this is the first report of echinostome metacercaria in this snail species. Results confirmed the role of C. annandalei as the second intermediate host of the trematode; however, the species identity of these echinostomes remains unclear. Comparative morphology of these metacercariae and their adult stage require further study, and molecular markers are necessary to confirm their identification. Prevalence and intensity of echinostomes metacercariae was significantly associated with snail species.
The United Nations and the North-South Partnership: Connecting the Past to the Future
Authors: Thakur Ramesh
Published: October 2020

As part of the special issue on “The United Nations at Seventy-Five: Looking Back to Look Forward,” this essay connects the past of the United Nations to its future from the perspective of the Global South. When the UN was created, most developing countries were colonies that played no role in writing the rules and designing the architecture of the post-1945 UN-centric global multilateral order. Today, countries in the Global South command a majority of the UN membership, but still mostly function as norm takers and are severely underrepresented in the UN Security Council—which functions as the geopolitical cockpit—and also in the senior ranks of the UN system, in the key posts in the Secretariat, and in the UN's funds and agencies. Gradually, however, these countries are using their numerical strength to give voice to their distinctive preferences, priorities, and values. This essay provides a broad-brush sketch of the changing nature of the North-South partnership on the UN's four overarching normative mandates of security, development, environment, and human rights. It includes a brief comment on the coronavirus pandemic within the framework of its main narrative of the continuing need for a UN-centric North-South partnership.
Severe fever with thrombocytopenia syndrome virus: a systematic review and meta-analysis of transmission mode
Authors: Huang X. Y. , He Z. Q. , Wang B. H. , Hu K. , Li Y. , Guo W. S.
Published: September 2020

Severe fever with thrombocytopenia syndrome (SFTS) is a disease with a high case-fatality rate that is caused by infection with the SFTS virus (SFTSV). Five electronic databases were systematically searched to identify relevant articles published from 1 January 2011 to 1 December 2019. The pooled rates with 95% confidence interval (CI) were calculated by a fixed-effect or random-effect model analysis. The results showed that 92 articles were included in this meta-analysis. For the confirmed SFTS cases, the case-fatality rate was 0.15 (95% CI 0.11, 0.18). Two hundred and ninety-six of 1384 SFTS patients indicated that they had been bitten by ticks and the biting rate was 0.21 (95% CI 0.16, 0.26). The overall pooled seroprevalence of SFTSV antibodies among the healthy population was 0.04 (95% CI 0.03, 0.05). For the overall seroprevalence of SFTSV in animals, the seroprevalence of SFTSV was 0.25 (95% CI 0.20, 0.29). The infection rate of SFTSV in ticks was 0.08 (95% CI 0.05, 0.11). In conclusion, ticks can serve as transmitting vectors of SFTSVs and reservoir hosts. Animals can be infected by tick bites, and as a reservoir host, SFTSV circulates continuously between animals and ticks in nature. Humans are infected by tick bites and direct contact with patient secretions.
Exploring the driving forces of waste generation in the Portuguese municipalities
Authors: Soukiazis Elias , Proença Sara
Published: September 2020

This paper explores the driving forces behind household waste generation in the Portuguese municipalities. The focus of the analysis is to empirically test the validity of the waste Kuznets curve (wKc) hypothesis, which postulates an inverted U-shaped relationship between waste generation and economic activity. Panel data is collected for 307 municipalities over the 2009–2018 period. Estimating the fixed-effects model and its dynamic versions of the waste generation equation, the decoupling hypothesis is confirmed, although it is only observed in the richest region of Lisbon and three other municipalities. Results suggest that the productive structure of the local economies is important for explaining waste generation behavior. Population ageing contributes negatively to waste generation, while population density and the development dichotomy are not important drivers in this process. Finally, tourism inflows have a positive effect on municipal waste generation, although the size of the impact is minimal.
The Fate of Sulfur and Chalcophile Elements During Crystallization of the Lunar Magma Ocean
Authors: Steenstra E. S. , Berndt J. , Klemme S. , Snape J. F. , Bullock E. S. , van Westrenen W.
Published: October 2020

To assess the viability of sulfide liquid saturation during crystallization of the lunar magma ocean (LMO), we present a new data set describing both the sulfur (S) concentration at sulfide liquid saturation (SCSS) and sulfide liquid‐silicate melt partition coefficients of many trace elements for various differentiated lunar magmas at lunar‐relevant conditions. Using these parameterizations, we model the SCSS and the distribution of the most chalcophile elements with progressive LMO crystallization in the absence and presence of sulfide liquids. Modeling results for different modes of LMO crystallization show that for proposed lunar mantle S abundances FeS sulfide liquid saturation is expected to occur between 96% and 98% of LMO crystallization. This is decreased to >91% for Fe‐S liquids with 30% Ni or Cu. Saturation of S‐poor sulfide liquids can occur at >75% of LMO crystallization. The timing of sulfide liquid saturation depends most strongly on the assumed S content of the lunar mantle following formation of the lunar core and on the sulfide liquid composition. Modeled abundances of chalcophile elements indicate that sulfide‐liquid saturation during late‐stage LMO crystallization would yield much lower abundances of Ni and Cu than observed in KREEP basalts and estimated for the urKREEP reservoir, as well as lower Ni/Co than observed in the latter. Sulfide liquids therefore did not affect moderately siderophile and chalcophile element fractionation within the LMO, supporting the hypothesis that the nonvolatile, siderophile element abundances of the lunar mantle reflect a phase of core formation and/or the addition of a meteoritic late veneer.
Soil pH Dominates the Distributions of Both 5‐ and 6‐Methyl Branched Tetraethers in Arid Regions
Authors: Duan Yanwu , Sun Qing , Werne Josef P. , Yang Huan , Jia Jia , Wang Leibin , Xie Haichao , Chen Fahu
Published: September 2020

Branched glycerol dialkyl glycerol tetraether (brGDGT)‐based indices are increasingly used for quantitative mean annual air temperature (MAAT) and soil pH reconstructions. However, large scatter in the relationship between the methylation index of 5‐methyl brGDGTs (MBT′5ME) and MAAT still exists in arid and/or cold regions, and specific reasons for that offset remain unclear. Here, we present the brGDGT distributions from 18 soil samples along an altitudinal transect spanning a large gradient in MAAT at Mount (Mt.) Tienshan in arid central Asia, which we compare with previously published data from 256 globally distributed soils. Our results indicate that a dramatic increase of brGDGT concentrations occurs at 2,500 m above sea level for the soils from Mt. Tienshan, and a different pattern of brGDGT distributions in response to environmental changes appears below and above this elevation. Soil pH is observed to control the distributions of both 5‐ and 6‐methyl brGDGTs in the soils from Mt. Tienshan and other arid regions. Importantly, we find that the fractional abundances of the 5‐methyl isomers of pentamethylated and hexamethylated brGDGTs (IIa, IIIa) show a distinct negative correlation with soil pH, and the noncyclopentane‐containing tetra‐methylated brGDGT (Ia) is not related to MAAT in arid soils, which can explain the remaining temperature offset of reconstructed MAAT based on the MBT′5ME index in arid regions. In addition, our data suggest that either the brGDGT‐producing community differs or brGDGT‐producers respond differently to temperature in arid relative to moist soils.
A Novel Approach to Identifying Mantle‐Equilibrated Zircon by Using Trace Element Chemistry
Authors: Ni Ziqin , Arevalo Ricardo , Piccoli Philip , Reno Barry L.
Published: October 2020

One of the requirements for inferring mantle redox states via zircon Ce/Ce* oxybarometry and Ti‐in‐zircon thermometry is to select mantle‐equilibrated zircon derived from melts that have not interacted with the hydrosphere nor assimilated exogenous materials. Traditional protocols for identifying mantle‐equilibrated zircon require a comprehensive examination of whole rock geochemistry in addition to zircon morphology, texture, and trace element and isotopic measurements. This study proposes a simple filter scheme for selecting mantle‐equilibrated zircon using trace element systematics alone (P, Ti, Y, Nb, rare earth elements [REE], Hf, Th, and U) to provide the geological context of zircon from three perspectives: (1) mineral inclusions; (2) source melt petrogenesis; and (3) zircon saturation context. The filter scheme presented here, comprising of 13 criteria, is established based on detailed classifications of 2,173 zircon analyses from 30 independent references and is shown to distinguish between nonmagmatic zircon, magmatic zircon with significant inclusions and/or sourced from highly enriched source melts, and mantle‐equilibrated zircon. The filter scheme is validated with known, well‐characterized mantle‐equilibrated Jack Hills zircon (n = 53) and derives an average mantle redox state of (sd) circa 4,400 Ma, in agreement with previously published results. Further application of the filter scheme to zircon dataset (n = 76) from three metasedimentary rocks successfully reveals the mantle‐equilibrated zircon in the dataset, and implies a mantle redox state of (sd) circa 2,950 Ma. This filter scheme can be applied to studies of out‐of‐context detrital and/or xenocrystic zircon in the future.
El Niño‐Driven Dry Season Flushing Enhances Dissolved Organic Matter Export From a Subtropical Watershed
Authors: Qu Liyin , Wu Yufang , Li Yan , Stubbins Aron , Dahlgren Randy A. , Chen Nengwang , Guo Weidong
Published: October 2020

The 2015/2016 super El Niño event resulted in a positive precipitation anomaly during dry seasons in the Jiulong River watershed, southeast China. Four years (2014–2017) of high frequency, in situ humic‐like fluorescent DOM (FDOMH) data in the Jiulong Estuary were coupled with extrapolation to a freshwater end‐member FDOMH concentration and river discharge data to estimate riverine FDOMH export. The wetter El Niño dry season was followed by lower FDOMH export during the subsequent wet season. Furthermore, in the dry season after El Niño reached its strongest phase, a 90–187% increase in FDOMH export occurred. If widespread, this pattern suggests El Niño events may enhance export of FDOMH from south China rivers in dry seasons resulting in seasonal and annual shunting of the terrestrial DOM export, modulating coastal carbon cycling. This study highlights the need to incorporate climate‐driven regulation patterns on DOM transport across the land‐ocean interface.
Abnormally Shallow Boundary Layer Associated With Severe Air Pollution During the COVID‐19 Lockdown in China
Authors: Su Tianning , Li Zhanqing , Zheng Youtong , Luan Qingzu , Guo Jianping
Published: October 2020

After the 2020 Lunar New Year, the Chinese government implemented a strict nationwide lockdown to inhibit the spread of the Coronavirus Disease 2019 (COVID‐19). Despite the abrupt decreases in gaseous emissions caused by record‐low anthropogenic activities, severe haze pollution occurred in northern China during the COVID lockdown. This paradox has attracted the attention of both the public and the scientific community. By analyzing comprehensive measurements of air pollutants, planetary boundary layer (PBL) height, and surface meteorology, we show that the severe air pollution episode over northern China coincided with the abnormally low PBL height, which had reduced by 45%, triggering strong aerosol‐PBL interactions. After dynamical processes initiated the temperature inversion, the Beijing metropolitan area experienced a period with continuously shallow PBLs during the lockdown. This unprecedented event provided an experiment showcasing the role of meteorology, in particular aerosol‐PBL interactions in affecting air quality.
Embryonic Rifting Zone Revealed by a High‐Density Survey on the Southern Margin of the Southern Okinawa Trough
Authors: Misawa Ayanori , Sato Masahiko , Furuyama Seishiro , Chang Jih‐Hsin , Inoue Takahiko , Arai Kohsaku
Published: October 2020

Offshore northern Ishigaki‐Jima Island, in the southern Okinawa Trough, offers outstanding opportunities to explore the rifting stage of a backarc system. We report the results of integrated marine geological and geophysical surveys with high‐density survey lines in this area. We identify a graben bounded by normal faults and extending approximately 59 km in an ENE‐WSW direction off‐axis of the southern Okinawa Trough. Submarine volcanoes with active hydrothermalism and associated intrusive structures lie in the graben. Magnetic anomaly and seismicity data in and around the graben suggest the presence of relatively shallow magma acting as a heat source. All features identified in and around the graben suggest active rifting in the southern Okinawa Trough.
Shallow Basin Structure and Attenuation Are Key to Predicting Long Shaking Duration in Los Angeles Basin
Authors: Lai Voon Hui , Graves Robert W. , Yu Chunquan , Zhan Zhongwen , Helmberger Don V.
Published: September 2020

Ground motions in the Los Angeles Basin during large earthquakes are modulated by earthquake ruptures, path effects into the basin, basin effects, and local site response. We analyzed the direct effect of shallow basin structures on shaking duration at a period of 2–10 s in the Los Angeles region through modeling small magnitude, shallow, and deep earthquake pairs. The source depth modulates the basin response, particularly the shaking duration, and these features are a function of path effect and not site condition. Three‐dimensional simulations using the CVM‐S4.26.M01 velocity model show good fitting to the initial portion of the waveforms at periods of 5 s and longer but fail to predict the long shaking duration during shallow events, especially at periods less than 5 s. Simulations using CVM‐H do not match the timing of the initial arrivals as well as CVM‐S4.26.M01, and the strong late arrivals in the CVM‐H simulation travel with an apparent velocity slower than observed. A higher‐quality factor than traditionally assumed may produce synthetics with longer durations but is unable to accurately match the amplitude and phase. Beamforming analysis using dense array data further reveals the long duration surface waves have the same back azimuth as the direct arrivals and are generated at the basin edges, while the later coda waves are scattered from off‐azimuth directions, potentially due to strong, sharp boundaries offshore. Improving the description of these shallow basin structures and attenuation model will enhance our capability to predict long‐period ground motions in basins.
Partial Melting of the Lower Oceanic Crust: Implications for Tracing the Slab Component in the Source of Mid‐Ocean Ridge Basalts
Authors: Wang Yu , Xu Yigang
Published: September 2020

The potential role of the lower oceanic crust in the source region of mid‐ocean ridge basalts has been examined by a series of partial melting experiments on three natural pyroxenite xenoliths entrained in alkali basalts well representing the lower oceanic crustal material at 1 GPa, 1100–1300°C. Layered experiments were also performed to simulate the reaction between lower oceanic crust‐derived melts and surrounding dunite and have successfully enabled the melt infiltration. Melt compositions are consistently basaltic and vary significantly as a function of melt fraction, and these lower oceanic crust‐derived melts are characterized by high Eu/Eu*, Nb/Ta, and Ba/Th values, especially for experiments conducted at 1300°C. No reaction zone is observed in layered experiments, and our results demonstrate that the compositional variations caused by the reaction with dunitic mantle in the lower oceanic crust‐derived melts are relatively minor at 1 GPa. Our melting experiments show that melting of the lower oceanic crust can provide trace element characteristics such as positive Sr and Eu anomalies and consistent Nb/Ta and Zr/Hf ratios, but it cannot account for the wide major element compositional variations (e.g., high FeOT and TiO2 contents) in mid‐ocean ridge basalt (MORB). Some component other than the surrounding dunite in the upwelling mantle flux is needed to substantially modify the major element compositions of the lower oceanic crust‐derived melts. It is quite likely that these lower oceanic crust‐derived melts could be extracted from the upwelling mantle while still preserving their trace element and isotopic imprintings.
On the Projected Decline in Droughts Over South Asia in CMIP6 Multimodel Ensemble
Authors: Aadhar Saran , Mishra Vimal
Published: October 2020

Recent studies based on the ensemble mean of Coupled Model Intercomparison Project 6 (CMIP6) General Circulation Models (GCMs, CMIP6‐GCMs hereafter) reported a decline in drought frequency over South Asia in the projected future climate. Here using the simulations from 16 CMIP6‐GCMs, we examine the potential causes of declining droughts in South Asia. We show that the projections based on the multimodel ensemble mean CMIP6‐GCMs are not reliable over South Asia. The multimodel ensemble mean is influenced mainly by the low‐skill GCMs, which show high bias in simulating the monsoon (June–September) season precipitation during the observed period (1951–2014). The low‐skill GCMs show a higher (20–30%) increase in the convective precipitation with a rise in the global mean temperature under the warming (1.5°C, 2.0°C, and 2.5°C worlds) climate. The GCMs with less bias (BEST‐GCMs) in the monsoon season precipitation and better seasonal cycle representation show lower sensitivity of convective precipitation to rise in global mean temperature. BEST‐GCMs exhibit significantly different projections in comparison to the multimodel ensemble mean from all 16 GCMs (ALL‐GCMs). In contrast to ALL‐GCMs, BEST‐GCMs project an increase in the frequency of droughts in South Asia under the future climate. Therefore, the projected risk of droughts over South Asia under the 1.5°C, 2.0°C, and 2.5°C warming levels is higher than previously reported based on the ensemble mean of CMIP6‐GCMs. A projected increase in the drought frequency in South Asia will have considerable implications for agricultural production and water availability.
Twelve‐Year Dynamics and Rainfall Thresholds for Alternating Creep and Rapid Movement of the Hooskanaden Landslide From Integrating InSAR, Pixel Offset Tracking, and Borehole and Hydrological Measurements
Authors: Xu Y. , Lu Z. , Schulz W. H. , Kim J.
Published: October 2020

The Hooskanaden landslide is a large (~600 m wide × 1,300 m long), deep (~30 – 45 m) slide located in southwestern Oregon. Since 1958, it has had five moderate/major movements that catastrophically damaged the intersecting U.S. Highway 101, along with persistent slow wet‐season movements and a long‐term accelerating trend due to coastal erosion. Multiple remote sensing approaches, borehole measurements, and hydrological observations have been integrated to interpret the motion behaviors of the slide. Pixel offset tracking of both Sentinel‐1 and Sentinel‐2 images was carried out to reconstruct the 3‐D displacement field of the 2019 major event, and the results agree well with field measurements. A 12‐year displacement history of the landslide from 2007 to 2019 has been retrieved by incorporating offsets from Light Detection and Ranging (LiDAR) digital elevation model (DEM) gradients and Interferometric Synthetic Aperture Radar (InSAR) processing of ALOS and Sentinel‐1 images. Comparisons with daily/hourly ground precipitation reveal that the motion dynamics are predominantly controlled by intensity and temporal pattern of rainfall. A new empirical threefold rainfall threshold was therefore proposed to forecast the dates for the moderate/major movements. This threshold relies upon antecedent water‐year and previous 3‐day and daily precipitation and was able to represent observed movement periods well. Adaptation of our threshold methodology could prove useful for other large, deep landslides for which temporal forecasting has long been generally intractable. The averaged characteristic hydraulic conductivity and diffusivity were estimated as 6.6 × 10−6 m/s and 6.6 × 10−4 m2/s, respectively, based on the time lags between rainfall pulses and slide accelerations. Hydrologic modeling using these parameters helps to explain the ability of the new rainfall threshold.
Protists as catalyzers of microbial litter breakdown and carbon cycling at different temperature regimes
Authors: Geisen Stefan , Hu Shunran , dela Cruz Thomas Edison E , Veen G F (Ciska)
Published: October 2020

Soil bacteria and fungi are key drivers of carbon released from soils to the atmosphere through decomposition of plant-derived organic carbon sources. This process has important consequences for the global climate. While global change factors, such as increased temperature, are known to affect bacterial- and fungal-mediated decomposition rates, the role of trophic interactions in affecting decomposition remains largely unknown. We designed synthetic microbial communities consisting of eight bacterial and eight fungal species and tested the influence of predation by a model protist, Physarum polycephalum, on litter breakdown at 17 and 21 °C. Protists increased CO2 release and litter mass loss by ~35% at 17 °C lower temperatures, while they only had minor effects on microbial-driven CO2 release and mass loss at 21 °C. We found species-specific differences in predator–prey interactions, which may affect microbial community composition and functioning and thus underlie the impact of protists on litter breakdown. Our findings suggest that microbial predation by fast-growing protists is of under-appreciated functional importance, as it affects decomposition and, as such, may influence global carbon dynamics. Our results indicate that we need to better understand the role of trophic interactions within the microbiome in controlling decomposition processes and carbon cycling.