bluuebunny/crossref_metadata_2025 huggingface dataset:
Bioeconomy perception by future stakeholders: Hearing from European forestry students
Authors: Masiero Mauro , Secco Laura , Pettenella Davide , Da Re Riccardo , Bernö Hanna , Carreira Ariane , Dobrovolsky Alexander , Giertlieova Blanka , Giurca Alexandru , Holmgren Sara , Mark-Herbert Cecilia , Navrátilová Lenka , Pülzl Helga , Ranacher Lea , Salvalaggio Alessandra , Sergent Arnaud , Sopanen Juuso , Stelzer Cristoph , Stetter Theresa , Valsta Lauri , Výbošťok Jozef , Wallin Ida
Published: October 2020

This article provides useful information for universities offering forestry programs and facing the growing demand for bioeconomy education. An explorative survey on bioeconomy perception among 1400 students enrolled in 29 universities across nine European countries offering forestry programs was performed. The data have been elaborated via descriptive statistics and cluster analysis. Around 70% of respondents have heard about the bioeconomy, mainly through university courses. Students perceive forestry as the most important sector for bioeconomy; however, the extent of perceived importance of forestry varies between countries, most significantly across groups of countries along a North–South European axis. Although differences across bachelor and master programs are less pronounced, they shed light on how bioeconomy is addressed by university programs and the level of student satisfaction with this. These differences and particularities are relevant for potential development routes towards comprehensive bioeconomy curricula at European forestry universities with a forestry focus.
Climate Change, Migration, and Civil Strife
Authors: Balsari Satchit , Dresser Caleb , Leaning Jennifer
Published: October 2020

Purpose of Review

In this article, we examine the intersection of human migration and climate change. Growing evidence that changing environmental and climate conditions are triggers for displacement, whether voluntary or forced, adds a powerful argument for profound anticipatory engagement.

Recent Findings

Climate change is expected to displace vast populations from rural to urban areas, and when life in the urban centers becomes untenable, many will continue their onward migration elsewhere (Wennersten and Robbins 2017; Rigaud et al. 2018). It is now accepted that the changing climate will be a threat multiplier, will exacerbate the need or decision to migrate, and will disproportionately affect large already vulnerable sections of humanity. Worst-case scenario models that assume business-as-usual approaches to climate change predict that nearly one-third of the global population will live in extremely hot (uninhabitable) climates, currently found in less than 1% of the earth’s surface mainly in the Sahara.

We find that the post–World War II regime designed to receive European migrants has failed to address population movement in the latter half of the twentieth century fueled by economic want, globalization, opening (and then closing) borders, civil strife, and war. Key stakeholders are in favor of using existing instruments to support a series of local, regional, and international arrangements to protect environmental migrants, most of whom will not cross international borders. The proposal for a dedicated UN agency and a new Convention has largely come from academia and NGOs. Migration is now recognized not only as a consequence of instability but as an adaptation strategy to the changing climate. Migration must be anticipated as a certainty, and thereby planned for and supported.
Swelling of Bentonite-Sand Mixtures After Long-Term Dissolution in Alkaline Solution
Authors: Xiang Guosheng , Ye Weimin
Published: October 2020

Alkaline solutions have significant effects on the mineral composition and on the microstructure of bentonite; in relevant geoenvironmental engineering applications, therefore, the properties of bentonite buffer materials must be taken into consideration in the presence of alkaline solutions. The objective of the present study was to determine the effect of alkaline conditions on the swelling of bentonite mixed with sand. Bentonite-sand mixtures were soaked in a NaOH solution and allowed to react over prescribed periods of 6, 12, and 24 months. Swelling deformation tests were conducted on the alkali-treated bentonite-sand mixtures; the swelling of the mixtures decreased significantly with increased reaction time. The fractal ec-σ relationship (ec is void ratio of bentonite, σ is vertical stress) was employed to express the swelling characteristics of the alkali-treated mixtures, wherein the swelling coefficient decreased as the bentonite content was reduced. Dissolution traces over the clay surfaces degraded the microstructural phase, thereby slightly increasing the fractal dimension. At higher dosages of bentonite, the swelling of bentonite-sand mixtures always followed a similar ec-σ relationship as that found for bentonite alone. On the contrary, in the mixtures with a small bentonite content that surpassed the designated threshold pressure, the void ratio of clay in the mixtures deviated from the ec-σ curve due to the appearance of the sand skeleton. The bentonite content for a particular bentonite-sand mixture at which deviation from the ec-σ curve began was ~50%. This deviation was almost negligible at 50% initial bentonite content in the bentonite-sand mixtures; after treatment with NaOH solution, however, a pronounced deviation in the ec-σ curve was observed which was caused mainly by the decrease in the bentonite percentage. Finally, the vertical pressure threshold was also estimated using the ec-σ relation for bentonite-sand mixtures with small bentonite contents over a range of various alkaline solution reaction times.
Animal hoarding and its effects on children: observations from a humane
law enforcement professional
Authors: Crawford Dez
Published: October 2020

Children raised in animal hoarding situations experience both short- and
long-term physical and emotional hazards. Far too often, the needs of
children are under-served due to lack of interagency cooperation, societal
misperceptions and other mitigating factors. These issues are discussed as
they relate to the effects of animal hoarding on children in the home.
Content is drawn from the lifelong experience of a humane law enforcement
and animal care professional. A sampling of case studies is offered, and
observations are presented regarding the immediate and long-term risks and
trauma experienced by children in the hands of people who hoard animals.
Included are a universal definition of animal hoarding, an explanation of
animal behaviour in hoarded homes, information about humane law enforcement
agencies and problems associated with a lack of interagency
cooperation.
Commercial Use of the Emblems of International Bodies: The Case of the International Committee of the Red Cross
Authors: RETAMOSA JOSÉ MANUEL VELASCO
Published: October 2020

The International Committee of the Red Cross (ICRC) is an international non-governmental organization (NGO) with a functional organization based on a structure of national societies and committees that independently represent it and carry out its work in numerous countries around the world. An essential element of this NGO’s functions, which are indeed very special, is the emblem that marks all of the activities the organization carries out, a symbol that is truly known in every corner of the globe. Given the organization’s prestige and everything its emblem represents, the need to protect this symbol arises in all contexts where it might be used, whether by the ICRC itself or by third parties, with or without authorization. This article reviews the numerous international, national, and internal rules that seek to regulate this emblem and its protection in all such models of its potential use.
Preparing for the Second Surge: Preventing Posttraumatic Stress Disorder and Building Resilience for Health Care Workers in the Face of COVID-19
Authors: Benham Todd L. , Hart Alexander , Bortolin Michelangelo , Court Michael , Groves John , Kraus Anthony , Newbury Brad , Voskanyan Amalia , Yogman Madeline , AlHajjaj Fahad , AlMalki Yousef , Alossaimi Bader , Awoniyi Oluwafunbi , Bardeesi Adham Sameer , Cattamanchi Srihari , Edwards Bridget , Hernandez Anthony , Issa Fadi , Manners Philip , Molloy Michael , Romney Douglas , Weiner Debra , Ciottone Gregory R.
Published: October 2020

The global community needs to be aware of the potential psychosocial consequences that may be experienced by health care workers who are actively managing patients with coronavirus disease (COVID-19). These health care workers are at increased risk for experiencing mood and trauma-related disorders, including posttraumatic stress disorder (PTSD). In this concept article, strategies are recommended for individual health care workers and hospital leadership to aid in mitigating the risk of PTSD, as well as to build resilience in light of a potential second surge of COVID-19.
Clade-specific variation in susceptibility of Candida auris to broad-spectrum ultraviolet C light (UV-C)
Authors: Chatterjee Piyali , Choi Hosoon , Ochoa Brennan , Garmon Gennifer , Coppin John D. , Allton Yonhui , Lukey Janell , Williams Marjory D. , Navarathna Dhammika , Jinadatha Chetan
Published: October 2020

Background:

Candida auris is an emerging and often multidrug-resistant fungal pathogen with an exceptional ability to persist on hospital surfaces. These surfaces can act as a potential source of transmission. Therefore, effective disinfection strategies are urgently needed. We investigated the efficacy of ultraviolet C light (UV-C) disinfection for C. auris isolates belonging to 4 different clades.

Methods:

In vitro testing of C. auris isolates was conducted using 106 colony-forming units (CFU) spread on 20-mm diameter steel carriers and exposed to a broad-spectrum UV-C light source for 10, 20, and 30 minutes at a 1.5 m (5 feet) distance. Post-UV survivors on the coupons were subsequently plated. Colony counts and log reductions were recorded, calculated, and compared to untreated control carriers. Identification of all isolates were confirmed by MALDI-TOF and morphology was visualized by microscopy.

Results:

We observed an increased susceptibility of C. auris to UV-C in 8 isolates belonging to clades I, II and IV with increasing UV exposure time. The range of log kill (0.8–1.19) was highest for these isolates at 30 minutes. But relatively no change in log kill (0.04–0.35) with increasing time in isolates belonging to clade III were noted. Interestingly, C. auris isolates susceptible to UV-C were mostly nonaggregating, but the isolates that were more resistant to UV exposure formed aggregates.

Conclusions:

Our study suggests variability in susceptibility to UV-C of C. auris isolates belonging to different clades. More studies are needed to assess whether a cumulative impact of prolonged UV-C exposure provides additional benefit.
Dynamically formed black hole binaries: In-cluster versus ejected mergers
Authors: Anagnostou O. , Trenti M. , Melatos A.
Published: October 2020

The growing number of black hole binary (BHB) mergers detected by the Laser Interferometer Gravitational-Wave Observatory have the potential to enable an unprecedented characterisation of the physical processes and astrophysical conditions that govern the formation of compact binaries. In this paper, we focus on investigating the dynamical formation of BHBs in dense star clusters through a state-of-the-art set of 58 direct N-body simulations with N$\leqslant200\,000$particles which include stellar evolution, gravitational braking, orbital decay through gravitational radiation, and galactic tidal interactions. The simulations encompass a range of initial conditions representing typical young globular clusters, including the presence of primordial binaries. The systems are simulated for$\sim 12$Gyr. The dataset yields 117 BHB gravitational wave (GW) events, with 97 binaries merging within their host cluster and 20 merging after having been ejected. Only 8% of all ejected BHBs merge within the age of the Universe. Systems in this merging subset tend to have smaller separations and larger eccentricities, as this combination of parameters results in greater emission of gravitational radiation. We confirm known trends from Monte Carlo simulations, such as the anti-correlation between the mass of the binary and age of the cluster. In addition, we highlight for the first time a difference at low values of the mass ratio distribution between in-cluster and ejected mergers. However, the results depend on assumptions on the strength of GW recoils, thus in-cluster mergers cannot be ruled out at a significant level of confidence. A more substantial catalogue of BHB mergers and a more extensive library of N-body simulations are needed to constrain the origin of the observed events.
Dietary diversity scores, nutrient intakes and biomarkers vitamin B12, folate and Hb in rural youth from the Pune Maternal Nutrition Study
Authors: Ganpule-Rao A. V. , Bhat D. , Yajnik C. S. , Rush E.
Published: October 2020

Hidden hunger is widespread in India. Individual dietary diversity score (IDDS) is a measure of the nutrient adequacy of the diet. The FAO has set guidelines for the measurement of dietary diversity: the IDDS and the minimum dietary diversity score for women (MDD-W) to assess nutritional deficiency, but validation against nutritional biomarkers is required. Using available data among rural youth (17 years) from the Pune Maternal Nutrition Study, the validity of DDS was assessed to measure deficiencies of vitamin B12, folate and Hb. Of the 355 boys and 305 girls, 19 % were classified as underweight, 57 % as vitamin B12 deficient (<150 pmol/l) and 22 % as anaemic (<120/130 g/l). Cereals, legumes and ‘other-vegetables’ were the most frequently consumed foods. More boys than girls consumed milk, flesh, eggs and micronutrient-dense foods. Median IDDS of 4 (interquartile range (IQR) 3–4) and MDD-W of 6 (IQR 5–7) were low. Youth with vitamin B12 deficiency had a higher likelihood of an IDDS ≤ 4 (1·89; 95 % CI 1·24, 2·87) or an MDD-W ≤ 5 (1·40; 95 % CI 1·02, 1·94). Youth with anaemia were more likely to have an IDDS ≤ 4 (1·76; 95 % CI 1·01, 3·14) adjusted for socio-economic scores, BMI, energy intake and sex. Folate deficiency was low (3 %) and was not associated with either score. Youth with lowest plasma vitamin B12 and Hb infrequently or never consumed dairy products/non-vegetarian foods. These rural Indian youth were underweight, had low DDS and consumed foods low in good-quality proteins and micronutrients. Associations of DDS with circulating micronutrients indicate that DDS is a valid measure to predict vitamin B12 deficiency and anaemia.
Environmental and economic impacts of pesticide treatment in the Yam Minisett Technique
Authors: Morse Stephen
Published: October 2020

White yam (Dioscorea rotundata) is an important tuber crop in a number of countries, but especially in West Africa where it serves as a food staple as well as a cash crop as excess production is sold in local markets. But the availability of quality planting material, most notably seed yams, for yam production remains an important constraint for farmers. Techniques have been developed to help address this limitation by cutting yam tubers into pieces (minisetts), treating them with the pesticide either via a seed dressing dust or pesticide ‘dips’ and planting to grow seed yams of the required size and quality. But while there have been many studies on the agronomy and adoption by farmers of these techniques, there have been fewer studies on their economic performance. Indeed, to date there have been no studies that compare the economic performance of treating setts compared to leaving them untreated, and neither has there been any analysis of the environmental impact of treating setts. This paper reports the results of a study designed to address these two gaps in knowledge and is based upon results from a series of farmer-managed seed yam plots established in the middle belt of Nigeria over 4 years (2013–2016). Results suggest that revenue and gross margin were higher for treated versus untreated setts although the latter still performed relatively well. Using the Field Use Environmental Impact Quotient (EIQ), the commonly recommended pesticide sett treatments were estimated to have a low-to-moderate environmental impact, and further research is needed to see how far pesticide use can be reduced to still be effective and minimise any environmental impact.
DEMOCRATIC OPPOSITION TO THE FAIR LABOR STANDARDS ACT OF 1938
Authors: Fleck Robert K.
Published: October 2020

This article uses roll-call voting and constituency data to provide an improved understanding of how and why the Fair Labor Standards Act (FLSA) of 1938 divided the Democratic Party. The evidence suggests, first, that the predominance of southerners among Democrats who opposed the FLSA resulted in part from the widespread disfranchisement of low-wage workers in the South and, second, that Democratic opposition to the FLSA in the House of Representatives reflected a weakening of the coalition that had passed so much legislation during the earlier years of the New Deal.
First zoeal stage morphology of Alpheus carlae and A. intrinsecus (Decapoda, Caridea, Alpheidae) obtained in the laboratory
Authors: Pantaleão João Alberto Farinelli , Pescinelli Régis Augusto , Costa Rogério Caetano , Cuesta Jose A. , Mantelatto Fernando Luis
Published: October 2020

The first zoeal stages of the snapping shrimps Alpheus carlae and A. intrinsecus from Brazil were obtained from laboratory-hatched specimens and a detailed morphological description is provided. The morphological characteristics of both species are compared with available descriptions of other Alpheus species with a known first zoeal stage. Remarks from a semi-quantitative comparison of species belonging to A. armillatus species complex (A. carlae and A. brasileiro) and a comparison between larvae of A. intrinsecus from two localities in Brazil are presented. It was possible to distinguish first zoea of both species from the other congeners based on morphology. No intraspecific variability was detected between A. intrinsecus larvae obtained from two locations. Some structures showed differences between species of the A. armillatus complex. However, generalizations and conclusions based on larval morphology for taxonomic rearrangements at this point need to be made with caution and accuracy, since data of a sufficient number of species are not yet available for comparison.
Integrating camera traps and community knowledge to assess the status of the Indian pangolinManis crassicaudatain the Eastern Ghats, India
Authors: Aditya Vikram , Komanduri Krishna Pavan , Subhedar Rohit , Ganesh Thyagarajan
Published: October 2020

Pangolins are the most trafficked animals globally. Although the Indian pangolinManis crassicaudataoccurs across the Indian subcontinent (excluding parts of the Himalayas and the north-east, where the Chinese pangolinManis pentadactylais present), it is categorized as Endangered on the IUCN Red List as a result of heavy poaching for its meat and scales. Several areas have not yet been surveyed for the occurrence of the Indian pangolin, one of which is the 16,948 km2tropical deciduous forests of the northern Eastern Ghats landscape in Andhra Pradesh. During December 2017–April 2018, we surveyed 750 km2of this landscape for the presence of the Indian pangolin, using camera traps. As an alternative method to document pangolin presence, and to identify factors driving hunting of the species, we also conducted, during the same period, a total of 60 semi-structured interviews with people in 30 villages. Interviewees reported the presence of pangolins in a majority of the grid cells that we surveyed with camera traps, particularly in moist deciduous forests distant from villages. However, the camera traps did not detect pangolins in 840 trap-days. Hunting of pangolins for their meat, which is consumed locally, and for their scales, which are traded, is most likely the reason for the rarity of the species in this landscape. A better understanding of the proximate and ultimate drivers of pangolin hunting is required, to inform proactive conservation management for this increasingly threatened species.
Perfect Torque Compensation of Planar 5R Parallel Robot in Point-to-Point Motions, Optimal Control Approach
Authors: Vezvari Mojtaba Riyahi , Nikoobin Amin , Ghoddosian Ali
Published: October 2020

In this paper, a new approach is presented for perfect torque compensation of the robot in point-to-point motions. The proposed method is formulated as an open-loop optimal control problem. The problem is defined as optimal trajectory planning with adjustable design parameters to compensate applied torques of a planar 5R parallel robot for a given task, perfectly. To illustrate the effectiveness of the approach, the obtained optimal path is used as the reference command in the experiment. The experimental outputs show that the performance index has been reduced by over 80% compared to the typical design of the robot.
Does the number of embryos loaded on a single cryo-carrier affect post-vitrification survival rate?
Authors: Aizer Adva , Noach-Hirsh Meirav , Dratviman-Storobinsky Olga , Haas Jigal , Orvieto Raoul
Published: October 2020

Background:

We aimed to assess whether the survival rate of embryos is influenced by the number of embryos/oocytes loaded on a single cryo-carrier during vitrification.

Methods:

This was a retrospective study that included 974 patients who underwent thawing of 1896 embryo-warming cycles between September 2016 and January 2020. A distinct analysis was made for cleavage stage embryos (2–10-cell stage) and blastocysts. For vitrification, embryos were placed in a Cryotop™ open device using a SAGE vitrification kit following the manufacturer’s instructions. Warming was carried using a SAGE warming vitrification kit according the manufacturer’s instructions.

Results:

Total post-vitrification survival rates of embryos at the cleavage stage or blastocyst stage was 94.8%. At the cleavage stage, cryo-preserving three embryos per single cryo-carrier gave the highest full intact embryo survival rate (91.5%) compared with one or two embryo(s) per single cryo-carrier (85.7%, P < 0.0002 and 87.3%, P < 0.004). Conversely, post warmed full intact blastocyst survival rate for two blastocysts was significantly lower compared with one blastocyst (76.7% vs. 87.9%, P < 0.0193) per single cryo-carrier.

Conclusion:

Post-thawing survival rate following vitrification is affected by the number of embryos per single cryo-carrier undergoing the vitrification equilibration phase, with the optimum number of three cleaved embryos or one blastocyst per single cryo-carrier. Further studies are required to determine the optimum number of cleaved embryos or blastocysts that should be loaded onto a single cryo-carrier vitrification device.
Ram semen quality can be assessed by flow cytometry several hours after post-fixation
Authors: Vašíček Jaromír , Svoradová Andrea , Baláži Andrej , Jurčík Rastislav , Macháč Marián , Chrenek Peter
Published: October 2020

Ram spermatozoa are very sensitive to any cold shock or oxidative damage, therefore making them unsuitable for prolonged storage or distant transport to specialized laboratories for flow-cytometric analysis. The aim of this study was to stain ram semen samples with several fluorescent markers and analyse their stability during formaldehyde fixation. Briefly, freshly collected semen samples were stained for apoptosis (annexin V-FITC, YO-PRO™-1 and FLICA), acrosomal damage (PNA-AF488 and FITC-conjugated antibody against GAPDHS), mitochondrial activity (Mitotracker probes), oxidative damage [dihydroethidium (DHE) and CellROX™ Green] and cell viability (live/dead fixable viability dyes). Next, samples were fixed in buffer containing formaldehyde and then washed. Stained sample were analyzed using flow cytometer before fixation, immediately after fixation, and at 5 h and 20 h post-fixation. Fluorescent signals and the proportion of positively stained spermatozoa were compared statistically in fresh and post-fixed samples. All examined markers, except YO-PRO-1 (decreased significantly, P < 0.05), retained their fluorescence intensities after fixation. In conclusion, several tested markers were able to withstand formaldehyde fixation of ram semen samples as follows: annexin V and FLICA for apoptosis; PNA for acrosomal status; MitoTracker Red CMXRos for mitochondrial activity; and CellROX Green for oxidative status in combination with a suitable live/dead fixable viability dye. This optimized methodology could help to comprehensively analyse the quality of ram semen from local farms countrywide.
Identifying Sensitive Measures of Cognitive Decline at Different Clinical Stages of Alzheimer’s Disease
Authors: Jutten Roos J. , Sikkes Sietske A.M. , Amariglio Rebecca E. , Buckley Rachel F. , Properzi Michael J. , Marshall Gad A. , Rentz Dorene M. , Johnson Keith A. , Teunissen Charlotte E. , Van Berckel Bart N.M. , Van der Flier Wiesje M. , Scheltens Philip , Sperling Reisa A. , Papp Kathryn V. ,   for the Alzheimer Disease Neuroimaging Initiative,   National Alzheimer’s Coordinating Center, the Harvard Aging Brain Study, and the Alzheimer Dementia Cohort
Published: October 2020

Objective:

Alzheimer’s disease (AD) studies are increasingly targeting earlier (pre)clinical populations, in which the expected degree of observable cognitive decline over a certain time interval is reduced as compared to the dementia stage. Consequently, endpoints to capture early cognitive changes require refinement. We aimed to determine the sensitivity to decline of widely applied neuropsychological tests at different clinical stages of AD as outlined in the National Institute on Aging – Alzheimer’s Association (NIA-AA) research framework.

Method:

Amyloid-positive individuals (as determined by positron emission tomography or cerebrospinal fluid) with longitudinal neuropsychological assessments available were included from four well-defined study cohorts and subsequently classified among the NIA-AA stages. For each stage, we investigated the sensitivity to decline of 17 individual neuropsychological tests using linear mixed models.

Results:

1103 participants (age = 70.54 ± 8.7, 47% female) were included: n = 120 Stage 1, n = 206 Stage 2, n = 467 Stage 3 and n = 309 Stage 4. Neuropsychological tests were differentially sensitive to decline across stages. For example, Category Fluency captured significant 1-year decline as early as Stage 1 (β = −.58, p < .001). Word List Delayed Recall (β = −.22, p < .05) and Trail Making Test (β = 6.2, p < .05) became sensitive to 1-year decline in Stage 2, whereas the Mini-Mental State Examination did not capture 1-year decline until Stage 3 (β = −1.13, p < .001) and 4 (β = −2.23, p < .001).

Conclusions:

We demonstrated that commonly used neuropsychological tests differ in their ability to capture decline depending on clinical stage within the AD continuum (preclinical to dementia). This implies that stage-specific cognitive endpoints are needed to accurately assess disease progression and increase the chance of successful treatment evaluation in AD.
Study Abroad in Africa: Learning about Race, Racism, and the Racial Legacy of America
Authors: Tolliver Derise E.
Published: October 2020

In 1998, the American Association of Colleges and Universities raised the question of what higher education could do to prepare graduates to address “the legacies of racism and the opportunities for racial reconciliation in the United States.” One of the most powerful and pedagogically rich approaches to facilitate learning about race, racial identity, and the impact of racism in America today is study abroad in Africa. With a history that includes dynasties and empires; the capture and enslavement of Africans and the transatlantic slave trade; and the structures of colonialism, neocolonialism, and apartheid (which have often been conceptualized as parallel to the institutionalized racism of America), the continent of Africa can be a wonderful classroom for this type of learning. This is particularly the case when the location of study is West Africa, by most accounts where the majority of people of African descent living in the United States have ancestral ties. Visits to and interactions around the monuments to and symbols and physical remnants of the complex historical relationships between Europeans and Africans can be a catalyst for stimulating challenging but ultimately rewarding discussions and growth with regard to issues of race and racism.
Does Channel Narrowing by Floodplain Growth Necessarily Indicate Sediment Surplus? Lessons From Sediment Transport Analyses in the Green and Colorado Rivers, Canyonlands, Utah
Authors: Dean David J. , Topping David J. , Grams Paul E. , Walker Alexander E. , Schmidt John C.
Published: October 2020

Analyses of suspended sediment transport provide valuable insight into the role that sediment supply plays in causing geomorphic change. The sediment supply within a river system evolves depending on the discharge, flood frequency and duration, changes in sediment input, and ecohydraulic conditions that modify sediment transport processes. Changes in supply can be evaluated through analyses of coupled changes in suspended sediment concentration and grain size. The concentration of sand in transport in the Green and Colorado Rivers is most strongly controlled by discharge and the bed sand grain size distribution. Since the 1950s, sand loads have decreased in response to declines in peak discharge in the Green River and coarsening of the bed sand in the Colorado River. However, changes in the bed sand grain size distribution are associated with large changes in suspended sand concentration in both rivers; concentration varies by a factor of ~3 in the Green River and a factor of ~8 in the Colorado River, depending on the bed sand grain size distribution. Analyses of hysteresis in suspended sediment measurements show that sediment depletion during annual floods is most strongly controlled by flood duration, with peak discharge being nearly equally important in the Green River. Despite channel narrowing in both rivers, periods of bed sand coarsening and sediment depletion during annual floods indicate that these rivers are not necessarily in sediment surplus. Channel narrowing appears to be strongly controlled by short‐term declines in flood magnitude and the ecohydraulic effects of vegetation and may not be indicative of the long‐term sediment budget.
An Introduction to the E3SM Special Collection: Goals, Science Drivers, Development, and Analysis
Authors: Leung L. Ruby , Bader David C. , Taylor Mark A. , McCoy Renata B.
Published: October 2020

Supported by the U.S. Department of Energy (DOE), the Energy Exascale Earth System Model (E3SM) project aims to optimize the use of DOE resources to address the grand challenge of actionable predictions of Earth system variability and change. This requires sustained advancement to (1) integrate model development with leading‐edge computational advances toward ultra‐high‐resolution modeling; (2) represent the coupled human‐Earth system to address energy sector vulnerability to variability and change; and (3) address uncertainty in model simulations and projections. Scientific development of the E3SM modeling system is driven by the simulation requirements in three overarching science areas centering on understanding the Earth's water cycle, biogeochemistry, and cryosphere systems and their future changes. This paper serves as an introduction to the E3SM special collection, which includes 50 papers published in several AGU journals. It provides an overview of the E3SM project, including its goals and science drivers. It also provides a brief history of the development of E3SM version 1 and highlights some key findings from papers included in the special collection.
Annual Net Community Production of Particulate and Dissolved Organic Carbon From a Decade of Biogeochemical Profiling Float Observations in the Northeast Pacific
Authors: Haskell W. Z. , Fassbender A. J. , Long J. S. , Plant J. N.
Published: October 2020

Carbon export out of the surface ocean via the biological pump is a critical sink for atmospheric carbon dioxide. This process transports organic carbon to the deep ocean through sinking particulate organic carbon (POC) and the downward transport of suspended POC and dissolved organic carbon (DOC). Changes in the relative contribution of each pathway can significantly affect the magnitude and efficiency of carbon export to depth. Net community production (NCP), an analog of carbon export under steady state assumptions, is typically estimated using budgets of biologically important chemical tracers in the upper ocean constrained by ship‐board or autonomous platform observations. In this study, we use measurements from biogeochemical profiling floats, the Ocean Station Papa mooring, and recently developed algorithms for carbonate system parameters to constrain budgets for three tracers (nitrate, dissolved inorganic carbon, and total alkalinity) and estimate NCP in the Northeast Pacific from 2009 to 2017. Using our multiple‐tracer approach, and constraining end‐member nutrient ratios of the POC and DOC produced, we not only calculate regional NCP throughout the annual cycle and across multiple depth horizons, but also partition this quantity into particulate and dissolved portions. We also use a particle backscatter‐based approach to estimate POC attenuation with depth and present a new method to constrain particle export across deeper horizons and estimate in situ export efficiency. Our results agree well with previously published estimates of regional carbon export annually and suggest that the approaches presented here could be used to assess the magnitude and efficiency of carbon export in other regions of the world's oceans.
Ionospheric Responses at Low Latitudes to the Annular Solar Eclipse on 21 June 2020
Authors: Huang Fuqing , Li Qiaoling , Shen Xuhui , Xiong Chao , Yan Rui , Zhang Shun‐Rong , Wang Wenbin , Aa Ercha , Zhong Jiahao , Dang Tong , Lei Jiuhou
Published: October 2020

In this study, we utilized both ground‐based and space‐borne observations including total electron content (TEC) from Beidou geostationary satellites, two‐dimensional TEC maps from the worldwide dense Global Navigation Satellite System receivers, ionosondes, and in situ electron density (Ne) and electron temperature (Te) from both Swarm and China Seismo‐Electromagnetic Satellite satellites, to investigate the low‐latitude ionospheric responses to the annular solar eclipse on 21 June 2020. The decrease in TEC during the eclipse at low latitudes showed a local time dependence with the largest depletions in the noon and afternoon sectors. It was also found that the TEC depletions at different latitudes in the equatorial ionization anomaly (EIA) region over the East Asian sector cannot solely be explained by the solar flux changes associated with the obscuration rate. The differences in TEC reduction between stations can be more than a factor of 2 at latitudes with the same obscuration rate of over 90%. Compared with TEC variations in the Northern Hemisphere, the TEC also underwent a considerable decrease in the EIA region in the conjugate hemisphere without eclipse shadow. Meanwhile, the hmF2 near the magnetic equator increased around the onset of the eclipse, indicating an enhancement of the eastward equatorial electric field. Furthermore, the TEC decrease during the eclipse in the EIA region in both hemispheres lasted for a long period of more than 7 hr after the eclipse, with a TEC depletion of 2–6 TEC units. The Ne from Swarm and China Seismo‐Electromagnetic Satellite satellites showed a complicated variation after the eclipse, whereas no visible change was observed in Te. The enhanced equatorial electric field, neutral wind changes, and the associated plasma transport act together to generate the observed ionospheric effects at low latitudes during the eclipse. Our results also suggest that the eclipse‐induced perturbations of dynamic processes can continue to impact the ionosphere after the eclipse.
Seismic Structure of a Postspreading Seamount Emplaced on the Fossil Spreading Center in the Southwest Subbasin of the South China Sea
Authors: Zhang Jie , Li Jiabiao , Ruan Aiguo , Ding Weiwei , Niu Xiongwei , Wang Wei , Tan Pingchuan , Wu Zhenli , Yu Zhiteng , Wei Xiaodong , Zhao Yanghui , Zhou Zhiyuan
Published: October 2020

Postspreading seamounts are unique seamounts built by volcanism after seafloor spreading had ceased. Limited understanding of their formation processes is mainly due to the lack of investigation. Therefore, we conducted a three‐dimensional wide‐angle seismic experiment in the Southwest Subbasin of the South China Sea and four profiles were acquired within the inactive spreading center over a postspreading seamount. Based on ocean bottom seismometer data, we report two‐dimensional velocity structures of the Longnan seamount. Our results show that a low P wave velocity body (2.9–5.0 km/s, 4 km thick) is observed within the seamount summit, suggesting that material has extensively erupted as volcaniclastic rocks and high‐porosity basalts. The extrusive/intrusive boundary is depressed beneath the seamount, indicating the absence of an intrusive core. Our results further show that the ratio of extrusive to intrusive volume is as high as 3.0 and that the accretion to the oceanic crust occurs in layer 2. Combined with an analysis of velocity structures of seamounts worldwide including seamounts in the South China Sea, we propose that the extrusive/intrusive ratio and type of crustal thickening are related to the magma supply mechanisms, and intrusive cores are more likely to be associated with a hot spot. The above analysis also suggests that the Longnan Seamount is a nonplume origin seamount and structurally different from other seamounts in the South China Sea. Ridge jumps in the South China Sea increase the duration or amount of volcanism, which could explain seamount structural differences.
Impact of Lake/Reservoir Expansion and Shrinkage on Energy and Water Vapor Fluxes in the Surrounding Area
Authors: Guo Ailun , Liu Shaomin , Zhu Zhongli , Xu Ziwei , Xiao Qing , Ju Qian , Zhang Yuan , Yang Xiaofan
Published: October 2020

Lakes and reservoirs are important components of freshwater. The expansion and shrinkage of lakes/reservoirs may have impacts on meteorological characteristics and the underlying surface conditions in the surrounding areas, which would further affect energy and water vapor fluxes. In this study, the expansion and shrinkage of the Guanting Reservoir during 2013–2017 were analyzed using remote sensing data. Data collected from the Huailai Remote Sensing Experiment Station were used to analyze the impact of reservoir expansion/shrinkage on energy and water vapor fluxes in the surrounding area. Results showed the annual expansion of the Guanting Reservoir from 2013 to 2017 and a seasonal variation characterized by expansion in spring, shrinkage in summer and autumn, and expansion again in winter was exhibited. Meanwhile, the evapotranspiration (ET) in the surrounding area increased by about 96%, from 446.6 mm in 2013 to 874.7 mm in 2017. In growing season (May to September), the seasonal shrinkage of the reservoir affected ET through net radiation, normalized difference vegetation index (NDVI), and deep soil moisture, while in nongrowing season (January to April and October to December), the seasonal expansion increased ET through the distance between 40‐m tower and the reservoir, net radiation, and surface soil moisture. In addition, with the reservoir expanding year by year, the difference in ET between the closer site and further site from the reservoir increased obviously, especially in the nongrowing season during the seasonal expansion of the reservoir. The findings of this study are beneficial for ecosystem restoration and sustainable development of lakes/reservoirs in arid and semiarid areas.
Arctic Ozone Loss in March 2020 and its Seasonal Prediction in CFSv2: A Comparative Study With the 1997 and 2011 Cases
Authors: Rao Jian , Garfinkel Chaim I.
Published: October 2020

Using reanalysis data, observations, and seasonal forecasts, the March Arctic ozone loss events in 1997, 2011, and 2020 and their predictability are compared. All of the three ozone loss events were accompanied by an extremely strong and cold polar vortex, with the shape and centroid of the ozone loss controlled by the polar vortex. The high autocorrelation of the March Arctic ozone at a lead/lag time of 1–2 months from observations might suggest that a reasonable prediction can be obtained if one initializes 1–2 months in advance. Based on the chemical scheme assessment in CFSv2 and several empirical models using the forecasted metric(s) of the stratospheric polar vortex as predictor(s), the predictability of the 2011 ozone loss event is shown to be longer (1–2 months) than the other two (~1 month), possibly due to a moderate La Niña and quasi‐biennial oscillation westerly winds favorable for the formation of a strong polar vortex. However, the overall predictive skills of ozone from empirical models (using a forecasted substitute index to forecast the Arctic ozone) during 1982–2020 are lower than the chemical module assessment in the forecast system, though empirical models have some skill. Contrary to the ozone predictions, the lower tropospheric temperature pattern in March 2011 is less reasonable than in 1997 and 2020. Similar conclusions are also true in other years (2005 versus 2016). Those findings might indicate a weak relationship between the Arctic ozone and the surface climate in the Northern Hemisphere.
Influence of Dunes on Channel‐Scale Flow and Sediment Transport in a Sand Bed Braided River
Authors: Unsworth Christopher A. , Nicholas Andrew P. , Ashworth Philip J. , Best James L. , Lane Stuart N. , Parsons Daniel R. , Sambrook Smith Gregory H. , Simpson Christopher J. , Strick Robert J. P.
Published: October 2020

Current understanding of the role that dunes play in controlling bar and channel‐scale processes and river morphodynamics is incomplete. We present results from a combined numerical modeling and field monitoring study that isolates the impact of dunes on depth‐averaged and near‐bed flow structure, with implications for morphodynamic modeling. Numerical simulations were conducted using the three‐dimensional computational fluid dynamics code OpenFOAM to quantify the time‐averaged flow structure within a 400 m × 100 m channel using digital elevation models (DEMs) for which (i) dunes and bars were present within the model and (ii) only bar‐scale topographic features were resolved (dunes were removed). Comparison of these two simulations shows that dunes enhance lateral flows and reduce velocities over bar tops by as much as 30%. Dunes influence the direction of modeled sediment transport at spatial scales larger than individual bedforms due to their effect on topographic steering of the near‐bed flow structure. We show that dunes can amplify, dampen, or even reverse the deflection of sediment down lateral bar slopes, and this is closely associated with 3‐D and obliquely orientated dunes. Sediment transport patterns calculated using theory implemented in depth‐averaged morphodynamic models suggest that gravitational deflection of sediment is still controlled by bar‐scale topography, even in the presence of dunes. However, improved parameterizations of flow and sediment transport in depth‐averaged morphodynamic models are needed that account for the effects of both dune‐ and bar‐scale morphology on near‐bed flow and sediment transport.
Impacts of Assimilation Frequency on Ensemble Kalman Filter Data Assimilation and Imbalances
Authors: He Huan , Lei Lili , Whitaker Jeffrey S. , Tan Zhe‐Min
Published: October 2020

The ensemble Kalman filter (EnKF) has been widely used in atmosphere, ocean, and land applications. The observing network has been significantly developed, and thus, observations with highly dense temporal resolutions have become available. To better extract information from dense temporal observations, one straightforward strategy is to increase the assimilation frequency. However, more frequent assimilation may exacerbate the model imbalance and result in degraded forecasts. To combat the imbalance caused by ensemble‐based data assimilation due to sampling error and covariance localization, three‐ and four‐dimensional incremental analysis update (IAU) were proposed, which gradually introduce the analysis increments into model rather than intermittently updating the state. The trade‐off between the assimilation frequency and imbalance is systematically explored here by using an idealized two‐layer model and the NOAA GFS. Results from the idealized two‐layer model show that increasing assimilation frequency can reduce errors for state variables that are not sensitive to imbalances. For state variable that carries the signal of the external gravity mode and is sensitive to imbalances, increasing assimilation frequency without (with) IAU reduces (increases) errors. Without IAU, more frequent updates result in smaller increments and less insertion noise, while the initialization of IAU cannot effectively mitigate the imbalances with increased assimilation frequency. Results with a low‐resolution version of the NOAA GFS demonstrate that increasing assimilation frequency from 6 to 2 h improves the errors and biases of forecasts verified with conventional and radiance observations, although gravity wave noise in the forecast is increased.
Exposure and Possible Risks of Engineered Nanomaterials in the Environment—Current Knowledge and Directions for the Future
Authors: Wigger Henning , Kägi Ralf , Wiesner Mark , Nowack Bernd
Published: October 2020

The consequences that engineered nanomaterials (ENMs) may cause in the environment have been under investigation for more than 15 years. Hundreds of millions of euros/dollars have been invested into safety issues of ENMs, and much progress has been made in the understanding of their fate and effects in the environment. After an initial phase of “observing the effects,” research has shifted toward elucidating the mechanisms of fate and ecotoxicological effects. This also included a stronger focus on exposure issues and the development of analytical methods and computational models to predict exposure. First environmental risk assessments for ENM were performed, and much progress has been achieved on the way to nanospecific and material‐specific assessments. The release of ENM from products and their transformation in technical and natural compartments profoundly affect the form in which the ENMs are present in the environment. A crucial aspect in all areas isifthere are truly nanospecific issues of the novel‐added functionalities of ENM that are different from dissolved metals, larger particles, or natural particles. This review outlines progress in understanding the environmental dimensions of ENMs and areas that merit further investigation: To what extent are ENMs different from their natural counterparts and how “long” do we need to track them in natural and technical systems? A major challenge will be in developing methods for studying particle‐mediated processes and their effects on ecosystems and organisms in a more general sense, going beyond just ENM, for example, to natural nanoparticles, microplastics, and extracellular vesicles.
Author Correction: Achyranthes bidentata polysaccharide can safely prevent NSCLC metastasis via targeting EGFR and EMT
Authors: Zhong Chunlian , Yang Jingyi , Lu Yusheng , Xie Huanzhang , Zai Shengyi , Zhang Chen , Luo Zhiying , Chen Xuanchen , Fang Xuanmo , Jia Lee
Published: October 2020

An amendment to this paper has been published and can be accessed via a link at the top of the paper.