bluuebunny/crossref_metadata_2025 huggingface dataset:
From digital literacy to digital competence: the teacher digital competency (TDC) framework
Authors: Falloon Garry
Published: March 2020

Over the years, a variety of frameworks, models and literacies have been developed to guide teacher educators in their efforts to build digital capabilities in their students, that will support them to use new and emerging technologies in their future classrooms. Generally, these focus on advancing students’ skills in using ‘educational’ applications and digitally-sourced information, or understanding effective blends of pedagogical, content and technological knowledge seen as supporting the integration of digital resources into teaching, to enhance subject learning outcomes. Within teacher education institutions courses developing these capabilities are commonly delivered as standalone entities, or there is an assumption that they will be generated by technology’s integration in other disciplines or through mandated assessment. However, significant research exists suggesting the current narrow focus on subject-related technical and information skills does not prepare students adequately with the breadth of knowledge and capabilities needed in today’s classrooms, and beyond. This article presents a conceptual framework introducing an expanded view of teacher digital competence (TDC). It moves beyond prevailing technical and literacies conceptualisations, arguing for more holistic and broader-based understandings that recognise the increasingly complex knowledge and skills young people need to function ethically, safely and productively in diverse, digitally-mediated environments. The implications of the framework are discussed, with specific reference to its interdisciplinary nature and the requirement of all faculty to engage purposefully and deliberately in delivering its objectives. Practical suggestions on how the framework might be used by faculty, are presented.
Impact of a Multi-step Heat Treatment on Different Manufacturing Routes of 18CrNiMo7-6 Steel
Authors: Mandal Paranjayee , Olasolo Maider , Da Silva Laurie , Lalvani Himanshu
Published: March 2020

Effect of an optimized multi-step heat treatment routine on conventional (machining from wrought bar stock) and alternate manufacturing routes (hot forging and cold rotary forging) for producing flat cylindrical-shaped machine drive components from 18CrNiMo7-6 steel was investigated. The microstructure and mechanical properties of the final component manufactured using these three different routes were analyzed using optical microscopy, electron backscatter diffraction (EBSD), hardness testing, electro-thermal mechanical testing (ETMT), and rotary bending fatigue testing (RBFT) before and after implementing the multi-step heat treatment. It was found that the multi-step heat treatment transformed the as-received microstructure into the tempered martensitic microstructure, improving hardness, tensile, and fatigue properties. The heat treatment produced desired properties for the components manufactured by all three different routes. However the cold rotary forging, which is the most material utilizing route over the others, benefited the most from the optimized heat treatment.
1H, 13C, 15N chemical shift assignments of SHP2 SH2 domains in complex with PD-1 immune-tyrosine motifs
Authors: Marasco Michelangelo , Kirkpatrick John P. , Carlomagno Teresa
Published: April 2020

Inhibition of immune checkpoint receptor Programmed Death-1 (PD-1) via monoclonal antibodies is an established anticancer immunotherapeutic approach. This treatment has been largely successful; however, its high cost demands equally effective, more affordable alternatives. To date, the development of drugs targeting downstream players in the PD-1-dependent signaling pathway has been hampered by our poor understanding of the molecular details of the intermolecular interactions involved in the pathway. Activation of PD-1 leads to phosphorylation of two signaling motifs located in its cytoplasmic domain, the immune tyrosine inhibitory motif (ITIM) and immune tyrosine switch motif (ITSM), which recruit and activate protein tyrosine phosphatase SHP2. This interaction is mediated by the two Src homology 2 (SH2) domains of SHP2, termed N-SH2 and C-SH2, which recognize phosphotyrosines pY223 and pY248 of ITIM and ITSM, respectively. SHP2 then propagates the inhibitory signal, ultimately leading to suppression of T cell functionality. In order to facilitate mechanistic structural studies of this signaling pathway, we report the resonance assignments of the complexes formed by the signaling motifs of PD-1 and the SH2 domains of SHP2.
Feasibility of the use of Lentinula edodes mycelium in terbinafine remediation
Authors: Kryczyk-Poprawa Agata , Piotrowska Joanna , Żmudzki Paweł , Opoka Włodzimierz , Muszyńska Bożena
Published: March 2020

A detailed understanding of the fate of xenobiotics introduced into the environment and the mechanisms involved in their biotransformation, biodegradation, and biosorption is essential to improve the efficiency of remediation techniques. Mycoremediation is a form of bioremediation technique that has become increasingly popular in recent years as fungi are known to produce various effective extracellular enzymes that have the potential to neutralize a wide variety of xenobiotics released into the environment. Hence, mycoremediation appears to be a promising technique for the removal of a wide array of toxins and pharmaceutical residues from a damaged environment and wastewater. This study primarily aimed to investigate whether white-rot fungus (Lentinula edodes) can be utilized for the bioremediation of common antifungal agent terbinafine, which is mainly available in the market as powder or cream. The cultures of L. edodes were cultivated in the medium containing terbinafine powder or terbinafine 1% cream, each at a final concentration of 0.1 mg mL−1. The addition of terbinafine in powder form have a negative effect on biomass growth (p < 0.05). The total amount of terbinafine in the dry weight of mycelium after culture was estimated to be 7.63 ± 0.45 mg and 12.52 ± 2.46 mg for powder and cream samples, respectively. In addition, there were no traces of terbinafine in any of the samples of medium used for culturing L. edodes after the experimental duration period. The biodegradation products of terbinafine were identified for the first time using UPLC/MS/MS. The biodegradation of terbinafine resulted in the loss of 1-naphthylmethanol, which occurred via oxidative deamination, N-demethylation, or tert-butyl group hydroxylation. The results of the study demonstrate that L. edodes mycelium can be effectively used for the remediation of terbinafine.
Refining high-quality leaf protein and valuable co-products from green biomass of Jerusalem artichoke (Helianthus tuberosus L.) for sustainable protein supply
Authors: Kaszás László , Alshaal Tarek , Kovács Zoltán , Koroknai Judit , Elhawat Nevien , Nagy Éva , El-Ramady Hassan , Fári Miklós , Domokos-Szabolcsy Éva
Published: March 2020

The present study evaluates the green biomass of Jerusalem artichoke (JA) as an alternative green protein. A leaf protein concentrate (LPC) was prepared from leafy shoots using biotechnological methods. Seven clones were compared to assess the importance of the genetic basis of JA, and alfalfa served as the control. The LPC content of JA was an average 39 g kg−1 of fresh biomass, while that of alfalfa was 32 g kg−1. The JA can produce up to 936 kg of protein ha−1 year−1 without fertilization under rainfed conditions. The crude protein content of the LPC varied from 24.2 to 31.4 m/m%, depending on clones and harvesting time, which was comparable to that of alfalfa LPC (~ 32.3%). The amino acid profile of the LPC of JA, particularly of the essential amino acids, was similar to alfalfa and soybean. In addition, our results confirmed that the polyunsaturated fatty acid (PUFA) content varied between 64 and 68% in the LPC fraction, regardless of the clone that was used, with linoleic acid and linolenic acid being the predominant PUFAs. In addition, unlike alfalfa, the content of arachidonic acid was 0.5% in the JA LPC. The tuber yield was significantly reduced because of the repeated harvesting of the shoot parts; however, the tubers obtained were sufficient to regenerate the plantation in the subsequent year, thus ensuring the renewable ability and sustainability of the green biomass of JA.
Convergent numerical approximation of the stochastic total variation flow
Authors: Baňas L’ubomír , Röckner Michael , Wilke André
Published: March 2020

We study the stochastic total variation flow (STVF) equation with linear multiplicative noise. By considering a limit of a sequence of regularized stochastic gradient flows with respect to a regularization parameter$$\varepsilon $$εwe obtain the existence of a unique variational solution of the STVF equation which satisfies a stochastic variational inequality. We propose an energy preserving fully discrete finite element approximation for the regularized gradient flow equation and show that the numerical solution converges to the solution of the unregularized STVF equation. We perform numerical experiments to demonstrate the practicability of the proposed numerical approximation.
Examining Approaches to Estimate the Prevalence of Catastrophic Costs Due to Tuberculosis from Small-Scale Studies in South Africa
Authors: Sweeney Sedona , Vassall Anna , Guinness Lorna , Siapka Mariana , Chimbindi Natsayi , Mudzengi Don , Gomez Gabriela B.
Published: April 2020

Background and Objective

In context of the End TB goal of zero tuberculosis (TB)-affected households encountering catastrophic costs due to TB by 2020, the estimation of national prevalence of catastrophic costs due to TB is a priority to inform programme design. We explore approaches to estimate the national prevalence of catastrophic costs due to TB from existing datasets as an alternative to nationally representative surveys.

Methods

We obtained, standardized and merged three patient-level datasets from existing studies on patient-incurred costs due to TB in South Africa. A deterministic cohort model was developed with the aim of estimating the national prevalence of catastrophic costs, using national data on the prevalence of TB and likelihood of loss to follow-up by income quintile and HIV status. Two approaches were tested to parameterize the model with existing cost data. First, a meta-analysis summarized study-level data by HIV status and income quintile. Second, a regression analysis of patient-level data also included employment status, education level and urbanicity. We summarized findings by type of cost and examined uncertainty around resulting estimates.

Results

Overall, the median prevalence of catastrophic costs for the meta-analysis and regression approaches were 11% (interquartile range [IQR] 9–13%) and 6% (IQR 5–8%), respectively. Both approaches indicated that the main burden of catastrophic costs falls on the poorest households. An individual-level regression analysis produced lower uncertainty around estimates than a study-level meta-analysis.

Conclusions

This paper presents a novel application of existing data to estimate the national prevalence of catastrophic costs due to TB. This type of model could be useful for researchers and policy makers looking to inform certain policy decisions; however, some uncertainties remain due to limitations in data availability. There is an urgent need for standardized reporting of cost data and improved guidance on methods to collect income data to improve these estimates going forward.
Prevalence of other autoimmune diseases in polyglandular autoimmune syndromes type II and III
Authors: Pham-Dobor G. , Hanák L. , Hegyi P. , Márta K. , Párniczky A. , Gergics M. , Sarlós P. , Erőss B. , Mezősi E.
Published: March 2020

Purpose

Polyglandular autoimmune syndromes (PAS) are complex, heterogeneous disorders in which various autoimmune diseases can occur, affecting both endocrine and non-endocrine organs. In this meta-analysis, the prevalence of associated autoimmune disorders was investigated in PAS II and III.

Methods

A comprehensive search in MEDLINE and Embase databases identified 479 studies with the keywords of PAS II and PAS III. 18 records containing a total of 1312 patients fulfilled our inclusion criteria (original studies reporting at least 10 cases and containing the combination of other autoimmune disorders) and were selected for further analysis. A meta-analysis of prevalence was performed using the random-effects model with the calculation of 95% confidence intervals (CI). Results of each meta-analysis were displayed graphically using forest plots.

Results

Distinction between PAS II and PAS III was made in 842 cases, of which 177 and 665 were PAS II and III (21.1 vs 78.9%), respectively. The prevalence of Hashimoto’s thyroiditis was significantly higher than that of Graves’s disease (39% [95% CI 17–65%] vs. 4% [95% CI 0–10%], respectively; p = 0.001). In PAS II, Addison’s disease (AD) coexisted with AITDs, T1DM or the combination of these conditions in 65, 18 and 10% of cases, respectively. In addition, one other endocrine and five non-endocrine organ-specific autoimmune disorders were reported. In PAS III, two other autoimmune endocrinopathies, six non-endocrine organ-specific, and four systemic autoimmune disorders were found in combination with AITDs.

Conclusions

AITDs, T1DM and AD are the most common combinations in PAS, thus screening for these conditions seems to be reasonable.
Measurement of temporal and spatial resolved rotational temperature in ignition sparks at atmospheric pressure
Authors: Michler Tobias , Toedter Olaf , Koch Thomas
Published: March 2020

In this work, the temporal and spatial rotational temperature, as an indicator of spark temperature in the gas, of an ignition spark at ambient pressure is determined. With optical emission spectroscopy, the rotational bands of the nitrogen C3Πu → B3Πg transition at a wavelength of 337 nm are for determination. In addition, the electrical values of the current and the voltage are measured with a digital storage oscilloscope. All measurements are performed with a common nickel spark plug and a commercial 90 mJ ignition coil. The dwell time of the coil is varied in four steps from 100 to 25% and the influence on the rotational temperature is measured. The results are split into the three spark phases: breakdown, arc discharge, and glow discharge. The results show a cold breakdown, which is independent from the dwell time. On average, arc discharge is the hottest discharge phase, while the glow discharge has a medium rotational temperature.
Nondestructive Quantification of Heavy Elements Through the Analysis of Beam Hardening Artifacts Using Double-Exposure X-ray Computed Tomography: A Theoretical Consideration
Authors: Nakashima Yoshito , Nakano Tsukasa
Published: March 2020

We present a theoretical background for heavy element quantification through the intensive analysis of beam hardening (cupping artifacts) in X-ray computed tomography (CT) images. Cupping artifacts resulting from X-ray CT using a polychromatic X-ray source are quantitatively analyzed with an analytical solution for a cylindrical sample of a homogeneous aqueous solution/suspension containing a heavy element. The theoretical solution reveals that the severity of cupping artifacts is strongly dependent on the sample chemistry and the acceleration voltage of the X-ray tube. Careful analysis of this dependency enabled simultaneous determination of the atomic number and molar concentration of the heavy element within a particular estimation error range. Significant improvement in terms of the accuracy of determining the atomic number was achieved by employing double-exposure X-ray CT.
The Association Between Sexual Disorders and the Quality of Life of Woman Patients With Multiple Sclerosis: Findings of a Prospective, Observational, and Cross-Sectional Survey
Authors: Kołtuniuk Aleksandra , Przestrzelska Monika , Karnas Aleksandra , Rosińczuk Joanna
Published: March 2020

Introduction

Multiple sclerosis (MS) is a progressive, chronic inflammatory demyelinating disease of the central nervous system, whose symptoms include sexual disorders. Sexual dysfunctions can influence on quality of life (QOL) of patients with MS.

Aim

To evaluate the occurrence of sexual disorders among women with MS and correlations between QOL, prevalence of sexual disorders, and level of sexual satisfaction.

Methods

Polish women (n = 101) aged 22–66 years with diagnosed MS were included in the study.

Main Outcome Measures

The Female Sexual Function Index, the Sexual Satisfaction Questionnaire, the Satisfaction with Life Scale, and the Multiple Sclerosis International Quality of Life Questionnaire were used. In addition, an Authors-Designed Questionnaire was used to collect sociodemographic data.

Results

More than half of the patients surveyed were totally or somewhat unsatisfied with their sex life, and 44.55% of the patients were diagnosed with significant sexual disorders. It was shown that patients with diagnosed sexual disorders and a low level of sexual satisfaction rated their QOL the lowest among all the surveyed patients.

Conclusion

Our findings indicate that sexual disorders and the level of sexual satisfaction correlate significantly with QOL in patients with MS. Sexual dysfunctions are a significant problem in women with MS; thus, they should be considered with comprehensive care.
Lorcaserin Administration has Pro-Ejaculatory Effects in Rats via 5-HT2C Receptors Activation: A Putative Pharmacologic Strategy to Delayed Ejaculation?
Authors: de Almeida Kiguti Luiz Ricardo , Pacheco Tainá Louise , Antunes Edson , Kempinas Wilma de Grava
Published: March 2020

Background

Lorcaserin is an anti-obesity drug whose weight loss effect results from 5-hydroxytryptamin (5-HT)2C receptors activation. The 5-HT2C receptor was shown to participate in the physiological control of ejaculation, but no data addressing a putative effect of lorcaserin on ejaculation exist.

Aim

To investigate the effects of lorcaserin in different in vitro and in vivo experimental models of ejaculation in rats.

Methods

Contractile responses to lorcaserin in rat seminal emission organs in vitro (prostatic and epididymal vas deferens, cauda epididymis, and seminal vesicles), analysis of male rat copulatory behavior, and electromyographic recording of bulbospongiosus muscle in anesthetized animals were studied.

Main Outcome Measures

The main outcome measures included in vitro contraction of seminal emission organs and evaluation of the male rat copulatory behavior. The male rat sexual behavior in terms of copulation latency, ejaculation latency, mount and intromission frequency, and ejaculation frequency of sexually experienced adult male rats with a receptive female were also recorded.

Results

Lorcaserin (1.0 nM to 1.0 mM) had no significant effects on the in vitro contractility of seminal emission organs smooth muscle (cauda epididymis, vas deferens, and seminal vesicles). On the other hand, lorcaserin administration (0.3–1.0 mg/kg, intravenous) induced ejaculation in anesthetized rats, which was prevented by the 5-HT2C-selective antagonist SB 242084 (0.1 and 0.3 mg/kg, intravenous). Single-dose treatment of non-anesthetized male rats with lorcaserin (1.0, 4.0, or 10 mg/kg, per os) induced non-copulating ejaculations in sexually naïve rats. Lorcaserin also had pro-ejaculation effects by decreasing the ejaculation threshold of copulating rats by half. The pro-ejaculatory effects of lorcaserin were reversible as the ejaculation threshold of treated rats recovered after a 1-week washout period.

Clinical Implications

Due to its reported clinical safety, repurposing lorcaserin for the treatment of delayed ejaculation may be suggested.

Strengths & Limitations

The pro-ejaculatory effect of lorcaserin administration and the role of 5-HT2C were demonstrated in different experimental models of ejaculation in rats. The lack of studies in putative experimental models of delayed ejaculation is a limitation of this study.

Conclusion

Our results demonstrate that the clinically approved 5-HT2C agonist lorcaserin is a strong facilitator of ejaculation in rats.
Tracheostomy colonisation and microbiological isolates of patients in intensive care units‐a retrospective study
Authors: Cader Segana Hasan Abdul , Shah Fahim Ahmed , Nair S.K.G.Reghunandanan
Published: March 2020

Objective

To find out the type of bacteria colonising the tracheostomy tube and to determine the antibiotic sensitivity pattern and resistance in patients who have had tracheostomy in intensive care unit (ICU) set up and to initiate proper empirical treatment in such patients.

Methods

The study was a retrospective review of patients who underwent tracheostomy at Ministry of Health, Sur Hospital, Oman January 2005 and December 2015. The Hospital has 4 bedded pediatric intensive care unit (PICU) and 10 bedded adult ICU which is headed by consultant anaesthetists, consultant physicians, ICU trained nurses and respiratory therapists. All patients who required mechanical ventilation and were therefore subject to an orotracheal intubation and those who underwent a conventional tracheostomy were considered for inclusion. Patients who had been intubated in other hospitals or ICUs, other airways infection issues were excluded from this study. Data's were collected from computer based hospital management system, operation theatre and registers in Medical records department and entered in a preformed questionnaire before thorough analysis. The specimens for swab was obtained from the cut tracheostomy tube tips and the samples were sent to microbiology laboratory for isolation of the organism and obtain an antibiogram to know the susceptibility and resistance to antibiotics. Data were analyzed by Statistical Package for Social Sciences (SPSS, version 16, Chicago, Inc) and the values are reported as number (%). The commonest isolated organism was Pseudomonas followed by Acinetobacter.

Results

During the ten year retrospective study, there were 108 patients included in our study with 56 males and 51 females. Fourteen different microorganisms were isolated during our study which included Pseudomonas aeruginosa (n = 39), Acinetobacter baumanii (n = 28), Klebsiella (n = 10) and coagulase negative staphylococcus (n = 6). The most commonest organisms in both genders was Pseudomonas aeruginosa closely followed by Acinetobacter baumanii. In children under age of 12, it was Pseudomonas aeruginosa and in adults the impending organism was Acinetobacter baumanii. In terms of antiobiograms, 89% of Acinetobacter, 38% of Staphylococcus aureus, 37% of Klebsiella and 54% of Proteus mirabilis were resistant to ciprofloxacin. These organisms were resistant to ceftazidime in 97%, 83%, 89% and 57% of the cases, respectively and resistant to imipenem in 7.4%, 18.2%, 1.8% and 8.1%.

Conclusions

In summary, this study presents the most common microorganisms colonized from tracheostomy of hospitalized patients and their pattern of antibiotic resistance. As our study showed, Pseudomonas is the most common microorganism isolated from tracheostomy tube. Ciprofloxacin was also the most prevalent antibiotic revealing resistant pattern. Moreover, most of the microorganisms were sensitive to imipenem and pipracillin‐tazobactam.
Diabatic Heating as a Pathway for Cyclone Clustering Encompassing the Extreme Storm Dagmar
Authors: Weijenborg C. , Spengler T.
Published: March 2020

Contrary to the general notion that extratropical cyclones reduce baroclinicity, the baroclinicity is found to be enhanced in the wake of the extreme winter storm Dagmar. Thus, individual storms can increase baroclinicity, yielding a pathway to secondary cyclogenesis and cyclone clustering. We use a recently introduced diagnostic for baroclinicity—the tendency equation for the isentropic slope—and found that strong diabatic heating due to moisture supply from the subtropical Atlantic led to the enhanced baroclinicity in the rear of Dagmar. Storms ensuing Dagmar benefited from this increased baroclinicity. In contrast to previous studies on the mechanisms of cyclone clustering, we only find weak evidence for Rossby wave breaking and thus propose diabatic heating as an alternative pathway to cyclone clustering.
Dynamic Recrystallization Can Produce Porosity in Shear Zones
Authors: Gilgannon James , Poulet Thomas , Berger Alfons , Barnhoorn Auke , Herwegh Marco
Published: March 2020

Creep cavities are increasingly recognized as an important syn‐kinematic feature of shear zones, but much about this porosity needs investigation. Largely, observations of creep cavities are restricted to very fine grained mature ultramylonites, and it is unclear when they developed during deformation. Specifically, a question that needs testing is should grain size reduction during deformation produce creep cavities? To this end, we have reanalyzed the microstructure of a large shear strain laboratory experiment that captures grain size change by dynamic recrystallization during mylonitization. We find that the experiment does contain creep cavities. Using a combination of scanning electron microscopy and spatial point statistics, we show that creep cavities emerge with, and because of, subgrain rotation recrystallization during ultramylonite formation. As dynamic recrystallization is ubiquitous in natural shear zones, this observation has important implications for the interpretation of concepts such as the Goetze criterion, paleopiezometery, and phase mixing.
The Tropical Atmospheric Conveyor Belt: A Coupled Eulerian‐Lagrangian Analysis of the Large‐Scale Tropical Circulation
Authors: Raiter Dana , Galanti Eli , Kaspi Yohai
Published: March 2020

The Hadley circulation is a key element of the climate system. It is traditionally defined as the zonally averaged meridional circulation in the tropics, therefore treated as a zonally symmetric phenomenon. However, differences in temperature between land and sea cause zonal asymmetries on Earth, dramatically affecting the circulation. This longitudinal dependence of the meridional circulation evokes questions about where and when the actual large‐scale tropical circulation occurs. Here, we look into the connection between the longitudinally dependent meridional circulation, and the actual large‐scale transport of air in the tropics using a coupled Eulerian and Lagrangian approach. Decomposing the velocity field into rotational and divergent components, we identify how each component affects the actual circulation. We propose an alternative definition for the circulation, which describes the actual path of air parcels in the tropics, as a tropical atmospheric conveyor belt.
Surface Ocean Warming Around Australia Driven by Interannual Variability and Long‐Term Trends in Southern Hemisphere Westerlies
Authors: Duran E. R. , England M. H. , Spence P.
Published: March 2020

The ocean surface temperature and sea level response around Australia to both interannual variability as well as observed and projected changes in surface winds is presented. A hindcast ocean experiment shows interannual southward shifts in the Southern Hemisphere westerly winds drive ocean surface warming events in the South Australian Basin. Twenty‐first century climate and ocean projections in an ensemble of the fifth Coupled Model Intercomparison Project (CMIP5) models show that wind trends could play a role comparable in magnitude to that of radiative warming in driving surface ocean temperature change in this region. To evaluate the wind's role in these projected changes, we use an ocean experiment perturbed by the projected end of 21st century wind anomalies to show that the wind trends alone can generate approximately half of the ocean surface warming and sea level rise predicted by the CMIP5 models in the Tasman Sea.
Contribution of Electroactive Humic Substances to the Iron‐Binding Ligands Released During Microbial Remineralization of Sinking Particles
Authors: Whitby Hannah , Bressac Matthieu , Sarthou Géraldine , Ellwood Michael J. , Guieu Cécile , Boyd Philip W.
Published: March 2020

Iron is a key micronutrient in seawater, but concentrations would be negligible without the presence of organic ligands. The processes influencing the ligand pool composition are poorly constrained, limiting our understanding of the controls on dissolved iron distributions. To address this, the release of iron and iron‐binding ligands during the microbial remineralization of sinking particles was investigated by deploying in situ particle interceptor/incubator devices at subsurface sites in the Mediterranean Sea and Subantarctic. Analyses revealed that the pool of released ligands was largely dominated by electroactive humic substances (74 ± 28%). The release of ligands during remineralization ensured that concurrently released iron remained in solution, which is crucial for iron regeneration. This study presents compelling evidence of the key role of humic ligands in the subsurface replenishment of dissolved iron and thus on the wider oceanic dissolved iron inventory, which ultimately controls the magnitude of iron resupplied to the euphotic zone.
Predictability of the Super IOD Event in 2019 and Its Link With El Niño Modoki
Authors: Doi Takeshi , Behera Swadhin K. , Yamagata Toshio
Published: March 2020

A positive Indian Ocean Dipole (IOD) in 2019 that reached the level of the strongest events occurred in 1994 and 1997 and caused disasters in countries around the Indian Ocean. Using a quasi real‐time ensemble seasonal prediction system based on the Scale Interaction Experiment‐Frontier climate model, its occurrence was predicted a few seasons ahead and the possible impacts were warned by overcoming the so‐called winter predictability barrier. The successful prediction of such a super event at long lead time may contribute to reducing the risks of socioeconomic losses by introducing suitable measures for adaptation. Here, we have investigated possible sources of the successful prediction by analyzing covariability of intermember anomalies defined as deviations from the mean in the ensemble reforecasts. Interestingly, it is found that the potential predictability of the 2019 super positive event is linked with the preexisting El Niño Modoki in the tropical Pacific.
A Sea Surface Height Perspective on El Niño Diversity, Ocean Energetics, and Energy Damping Rates
Authors: Shi Jian , Fedorov Alexey V. , Hu Shineng
Published: March 2020

Ocean energetics is a useful framework for understanding El Niño–Southern Oscillation; however, its key element, available potential energy (APE), requires accurate ocean subsurface data that are hard to measure. Here, we describe a sea surface height‐based index, SSHI, that accurately captures APE variations and can be easily computed from satellite observations. Using SSHI, we obtain an observation‐based estimate of the APE damping timescale of approximately 1.7 years, slightly longer than previous ocean reanalysis‐based estimates. Furthermore, SSHI serves as an indicator for El Niño “flavors” while recording the relative strength of the thermocline feedback. SSHI captures a decadal shift in El Niño–Southern Oscillation properties in early 2000s, with a more tilted mean thermocline and weaker thermocline slope variations indicative of the “Central Pacific” El Niño type dominating the past two decades, whereas SSH averaged over the tropical Pacific (a proxy for upper‐ocean heat content) shows a significant rising trend over this time.
How Variable Is Mixing Efficiency in the Abyss?
Authors: Ijichi Takashi , St. Laurent Louis , Polzin Kurt L. , Toole John M.
Published: March 2020

Mixing efficiency is an important turbulent flow property in fluid dynamics, whose variability potentially affects the large‐scale ocean circulation. However, there are several confusing definitions. Here we compare and contrast patch‐wise versus bulk estimates of mixing efficiency in the abyss by revisiting data from previous extensive field surveys in the Brazil Basin. Observed patch‐wise efficiency is highly variable over a wide range of turbulence intensity. Bulk efficiency is dominated by rare extreme turbulence events. In the case where enhanced near‐bottom turbulence is thought to be driven by breaking of small‐scale internal tides, the estimated bulk efficiency is 20%, close to the conventional value of 17%. On the other hand, where enhanced near‐bottom turbulence appears to be convectively driven by hydraulic overflows, bulk efficiency is suggested to be as large as 45%, which has implications for a further significant role of overflow mixing on deep‐water mass transformation.
Climate Change Projections for the Australian Monsoon From CMIP6 Models
Authors: Narsey S. Y. , Brown J. R. , Colman R. A. , Delage F. , Power S. B. , Moise A. F. , Zhang H.
Published: March 2020

Climate change projections for the Australian monsoon have been highly uncertain in previous generations of coupled climate models. The new Coupled Model Intercomparison Project Phase 6 (CMIP6) ensemble provides an opportunity to address the uncertainty in future projections for northern Australia. We find that the range in Australian monsoon projections from the available CMIP6 ensemble is substantially reduced compared to CMIP5, although models continue to disagree on the magnitude and direction of change. While previous CMIP5 studies identified warming in the western equatorial Pacific as important for Australian monsoon projections, here we show that the western Pacific is not strongly connected to northern Australian precipitation changes in the CMIP6 models. By comparing groups of models based on their future projections, we note that the model‐to‐model differences in Australian monsoon projections are congruent with the zonally averaged precipitation response in the Southern Hemisphere tropics within each model.
Response of Ionospheric Equatorial Ionization Crests to Lunar Phase
Authors: Wu Tsung‐Yu , Liu Jann‐Yenq , Lin Chi‐Yen , Chang Loren C.
Published: March 2020

The strength, appearance time, and latitudinal location of the equatorial ionization anomaly (EIA) crest response to the lunar phase are examined using the total electron content of global ionosphere maps during the 18‐year period of 2000–2017. The total electron content of the EIA crest reveals semidiurnal tides with 12.42‐hr period, while the appearance time and latitude of the EIA crests present prominent semimonthly lunar tides of 14.77‐day period. The EIA crests on new/full moon (first/third quarter) lead (lag) those of the overall 18‐year average by about 20–40 min, while the EIA crests move the furthest poleward and equatorward 2–5 days after new/full moon and first/third quarter, respectively. Amplitudes of the semimonthly lunar tide in the EIA crest appearance times and latitudes yield the greatest value around perihelion and the smallest value around aphelion, which shows that the solar declination and seasonal effects are important.
Excessive Momentum and False Alarms in Late‐Spring ENSO Forecasts
Authors: Tippett Michael K. , L'Heureux Michelle L. , Becker Emily J. , Kumar Arun
Published: March 2020

The unanticipated stalled El Niño‐Southern Oscillation (ENSO) evolution of 2014 raises questions about the reliability of the coupled models that were used for forecast guidance. Here we have analyzed the skill and reliability of forecasts of the Niño 3.4 tendency (3‐month change) in the North American multimodel ensemble (1982–2018). We found that forecasts initialized April–June (AMJ) have “excessive momentum” in the sense that the forecast Niño 3.4 tendency is more likely to be a continuation of the prior observed conditions than it should be. Models tend to predict warming when initialized after observed warming conditions and cooling when initialized after observed cooling conditions. Excessive momentum appears in AMJ forecast busts and false alarms including the 2014 one. In some models, excessive momentum appears to be related to model formulation rather than initialization. A concerning trend is that four of the nine years with AMJ forecast busts occurred in the last decade.
Tectonic Uplift Destabilizes Subsea Gas Hydrate: A Model Example From Hikurangi Margin, New Zealand
Authors: Burton Zachary F. M. , Kroeger Karsten F. , Hosford Scheirer Allegra , Seol Yongkoo , Burgreen‐Chan Blair , Graham Stephan A.
Published: March 2020

Rising ocean temperatures and falling sea level are commonly cited as mechanisms of marine gas hydrate destabilization. More recently, uplift—both isostatic and tectonic—has been invoked. However, the effect of tectonic shortening and uplift on gas hydrate stability zone extent has not been validated via integrated computational modeling. Here, modeling along the Hikurangi margin of New Zealand illustrates the mechanism of tectonic uplift as a driver of gas hydrate destabilization. We simulate how tectonic uplift and shortening affect the presence and decrease the extent of a gas hydrate stability zone. We suggest that resultant gas hydrate destabilization in the marine realm may impact the global carbon cycle and oceanic chemistry over geologic time.
Sensitivity of Tropospheric Ozone Over the Southeast USA to Dry Deposition
Authors: Baublitz Colleen B. , Fiore Arlene M. , Clifton Olivia E. , Mao Jingqiu , Li Jingyi , Correa Gus , Westervelt Daniel M. , Horowitz Larry W. , Paulot Fabien , Williams A. Park
Published: March 2020

Dry deposition (DD) is a major loss process for tropospheric ozone and some reactive nitrogen and carbon precursors. We investigate the response of summertime ozone and its production chemistry over the Southeast United States (USA) to variability in this sink. Turning off DD of oxidized nitrogen, ozone, or all species over the United States in the Geophysical Fluid Dynamics Laboratory AM3 model increases regional mean surface ozone by 5, 18, or 25 ppb, respectively. Additional sensitivity simulations demonstrate that, assuming linearity, surface ozone has a similar sensitivity to ozone DD as to NOx emissions. Trends in ozone production efficiency derived from observed relationships between ozone and precursor oxidation products may not solely reflect precursor emission changes if ozone DD varies (e.g., with meteorology). We conclude that DD variability merits consideration when interpreting observed ozone trends. Quantifying the impact of changes in sinks versus sources will require long‐term DD measurements across the region of interest.
Homogenization of Dissolution and Enhanced Precipitation Induced by Bubbles in Multiphase Flow Systems
Authors: Jiménez‐Martínez Joaquín , Hyman Jeffrey D. , Chen Yu , Carey J. William , Porter Mark L. , Kang Qinjun , Guthrie George , Viswanathan Hari S.
Published: March 2020

Multiphase flow is ubiquitous in subsurface energy applications and natural processes, such as oil recovery, CO2 sequestration, and water flow in soils. Despite its importance, we still lack a thorough understanding of the coupling of multiphase flow and reaction of transported fluids with the confining media, including rock dissolution and mineral precipitation. Through the use of geomaterial microfluidic flow experiments and high‐performance computer simulations, we identify key pore‐scale mechanisms that control this coupling. We compare the reactivity of fractured limestone with CO2‐saturated brine (single phase) and a mixture of supercritical (sc) CO2 and CO2‐saturated brine (multiphase). We find that the presence of scCO2 bubbles significantly changes both the flow dynamics and the resulting reaction patterns from a single‐phase system, spatially homogenizing the rock dissolution. In addition, bubbles redirect oversaturated fluid into low‐velocity regions, thereby enhancing carbonate precipitation occurs.
Groundwater Release on Early Mars: Utilizing Models and Proposed Evidence for Groundwater Release to Estimate the Required Climate and Subsurface Water Budget
Authors: Palumbo Ashley M. , Head James W.
Published: March 2020

It has been proposed that groundwater was released onto the early martian surface in several locations, including Meridiani Planum, NE Hellas, Terra Sirenum, the northern lowlands, and Gale crater. We assume that groundwater was released in a manner similar to a groundwater‐fed lake on Earth and then use a combination of a global climate model and mathematical relationships to place lower limit estimates on the early climate and subsurface water inventory that are required for groundwater release to occur at all of these locations. We find that the minimum required conditions are global mean annual temperature >284 K and a subsurface water inventory >496 m global equivalent layer. Additionally, thermal models predict that if such warm conditions occurred from punctuated heating in an otherwise “cold and icy” climate, the warm conditions must have persisted for thousands of years in order to remove the cryosphere and permit groundwater release.
Fragments Delivered by Secondary Craters at the Chang'E‐4 Landing Site
Authors: Ding Chunyu , Xiao Zhiyong , Wu Bo , Li Yuan , Prieur Nils C. , Cai Yuzhen , Su Yan , Cui Jun
Published: March 2020

The Chang'E‐4 landing site is depleted with boulders seen from both orbit and surface. However, the Yutu‐2 rover came across thousands of concreted fragments in and around an abnormally fresh crater that has more elevated northwestern rims. The origin of the fragments is crucial to resolve the provenances of surface materials detected by the rover. The lunar penetrating radar performed two in‐and‐out scans for the blocky ejecta, revealing that the subsurface materials have indistinguishable radar permittivity with the surrounding regolith. Forward modeling of electromagnetic wave propagation shows that the fragments were not an original component in the subsurface. This crater is among the several fresh craters photoed by the rover, and they are located in an eastern extension ray of the Zhinyu crater. The small craters are likely secondaries of Zhinyu, and the fragments contain a mixture of shattered projectiles and most likely compacted regolith clumps formed during the secondary impacts.
Relative Roles of Low‐Level Wind Speed and Moisture in the Diurnal Cycle of Rainfall Over a Tropical Island Under Monsoonal Flows
Authors: Zhu Lei , Chen Xingchao , Bai Lanqiang
Published: March 2020

Using satellite observations and reanalysis data, this study investigates the relative roles of low‐level wind speed and moisture content in the rainfall diurnal cycle over a tropical island influenced by monsoonal winds. Results show that the spatiotemporal characteristics of rainfall over the island are evidently influenced by the two factors. Specifically, the spatial distribution of rainfall is primarily determined by the low‐level wind speeds, while the rainfall diurnal cycle is influenced by both factors. Weaker low‐level wind speed leads to stronger and wider inland convergence and afternoon precipitation, which are mainly produced by the inland penetrating sea breeze fronts. Nighttime rainfall over the island is closely related to the inertial oscillation. Stronger nocturnal rainfall can be found with higher low‐level moisture content and stronger monsoonal winds. The multiscale interactions between the large‐scale circulation, land–sea breezes, and inertial oscillation play essential roles in modulating the rainfall over this tropical island.
Future Changes of Summer Monsoon Characteristics and Evaporative Demand Over Asia in CMIP6 Simulations
Authors: Ha Kyung‐Ja , Moon Suyeon , Timmermann Axel , Kim Daeha
Published: March 2020

Future greenhouse warming is expected to influence the characteristics of global monsoon systems. However, large regional uncertainties still remain. Here we use 16 Coupled Model Intercomparison Project Phase 6 (CMIP6) models to determine how the length of the summer rainy season and precipitation extremes over the Asian summer monsoon domain will change in response to greenhouse warming. Over East Asia the models simulate on average on the earlier onset and later retreat; whereas over India, the retreat will occur later. The model simulations also show an intensification of extreme rainfall events, as well as an increase of seasonal drought conditions. These results demonstrate the high volatility of the Asian summer monsoon systems and further highlight the need for improved water management strategies in this densely populated part of the world.
Climate Change and Social Unrest: A 6,000‐Year Chronicle From the Eastern Mediterranean
Authors: Kaniewski David , Marriner Nick , Cheddadi Rachid , Fischer Peter M. , Otto Thierry , Luce Frédéric , Van Campo Elise
Published: March 2020

The history of the Eastern Mediterranean is punctuated by major crises that have influenced many of the region's established socioeconomic models. Recent studies have underscored the role of drought and temperature oscillations in driving changes but attempts to quantify their magnitude remain equivocal, hindering long‐term assessments of the potential interplay between climate and society. Here, we fill this knowledge gap using a 6,000‐year pollen‐based reconstruction of temperature and precipitation from Hala Sultan Tekke, Cyprus. We find that major social changes and plague outbreaks often occurred in tandem with cooler climate conditions, with anomalies ranging from −3 ± 0.4 °C to −1 ± 0.5 °C, coupled with changing precipitation patterns. We suggest that major climate changes may weaken societies by affecting primary livelihood systems. This long‐term view highlights recurrent cold periods in the Eastern Mediterranean's climate history and advocates that, despite frequent adversity and pandemics, Near Eastern populations adapted and were ultimately resilient to major climate changes.
New insights into the functions of Cox-2 in skin and esophageal malignancies
Authors: Moon Hyeongsun , White Andrew C. , Borowsky Alexander D.
Published: April 2020

Understanding the cellular and molecular mechanisms of tumor initiation and progression for each cancer type is central to making improvements in both prevention and therapy. Identifying the cancer cells of origin and the necessary and sufficient mechanisms of transformation and progression provide opportunities for improved specific clinical interventions. In the last few decades, advanced genetic manipulation techniques have facilitated rapid progress in defining the etiologies of cancers and their cells of origin. Recent studies driven by various groups have provided experimental evidence indicating the cellular origins for each type of skin and esophageal cancer and have identified underlying mechanisms that stem/progenitor cells use to initiate tumor development. Specifically, cyclooxygenase-2 (Cox-2) is associated with tumor initiation and progression in many cancer types. Recent studies provide data demonstrating the roles of Cox-2 in skin and esophageal malignancies, especially in squamous cell carcinomas (SCCs) occurring in both sites. Here, we review experimental evidence aiming to define the origins of skin and esophageal cancers and discuss how Cox-2 contributes to tumorigenesis and differentiation.