bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards Designing Profitable Courses: Predicting Student Purchasing Behaviour in MOOCs
Authors: Alshehri Mohammad , Alamri Ahmed , Cristea Alexandra I. , Stewart Craig D.
Published: March 2021

Since their ‘official’ emergence in 2012 (Gardner and Brooks 2018), massive open online courses (MOOCs) have been growing rapidly. They offer low-cost education for both students and content providers; however, currently there is a very low level of course purchasing (less than 1% of the total number of enrolled students on a given online course opt to purchase its certificate). The most recent literature on MOOCs focuses on identifying factors that contribute to student success, completion level and engagement. One of the MOOC platforms’ ultimate targets is to become self-sustaining, enabling partners to create revenues and offset operating costs. Nevertheless, analysing learners’ purchasing behaviour on MOOCs remains limited. Thus, this study aims to predict students purchasing behaviour and therefore a MOOCs revenue, based on the rich array of activity clickstream and demographic data from learners. Specifically, we compare how several machine learning algorithms, namely RandomForest, GradientBoosting, AdaBoost and XGBoost can predict course purchasability using a large-scale data collection of 23 runs spread over 5 courses delivered by The University of Warwick between 2013 and 2017 via FutureLearn. We further identify the common representative predictive attributes that influence a learner’s certificate purchasing decisions. Our proposed model achieved promising accuracies, between 0.82 and 0.91, using only the time spent on each step. We further reached higher accuracy of 0.83 to 0.95, adding learner demographics (e.g. gender, age group, level of education, and country) which showed a considerable impact on the model’s performance. The outcomes of this study are expected to help design future courses and predict the profitability of future runs; it may also help determine what personalisation features could be provided to increase MOOC revenue.
Covid-19 and the need for more history and philosophy of RNA
Authors: Guttinger Stephan
Published: March 2021

RNA is central to the COVID-19 pandemic—it shapes how the SARS Coronavirus 2 (SARS-CoV-2) behaves, and how researchers investigate and fight it. However, RNA has received relatively little attention in the history and philosophy of the life sciences. By analysing RNA biology in more detail, philosophers and historians of science could gain new and powerful tools to assess the current pandemic, and the biological sciences more generally.
Primer biases in the molecular assessment of diet in multiple insectivorous mammals
Authors: Browett Samuel S. , Curran Thomas G. , O’Meara Denise B. , Harrington Andrew P. , Sales Naiara Guimarães , Antwis Rachael E. , O’Neill David , McDevitt Allan D.
Published: March 2021

Our understanding of trophic interactions of small insectivorous mammals has been drastically improved with the advent of DNA metabarcoding. The technique has continued to be optimised over the years, with primer choice repeatedly being a vital factor for dietary inferences. However, the majority of dietary studies examining the effect of primer choice often rely on in silico analyses or comparing between species that occupy an identical niche type. Here, we apply DNA metabarcoding to empirically compare the prey detection capabilities of two widely used primer sets when assessing the diets of a flying (lesser horseshoe bat; Rhinolophus hipposideros) and two ground-dwelling insectivores (greater white-toothed shrew; Crocidura russula and pygmy shrew; Sorex minutus). Although R. hipposideros primarily rely on two prey orders (Lepidoptera and Diptera), the unique taxa detected by each primer shows that a combination of primers may be the best approach to fully describe bat trophic ecology. However, random forest classifier analysis suggests that one highly degenerate primer set detected the majority of both shrews’ diet despite higher levels of host amplification. The wide range of prey consumed by ground-dwelling insectivores can therefore be accurately documented from using a single broad-range primer set, which can decrease cost and labour. The results presented here show that dietary inferences will differ depending on the primer or primer combination used for insectivores occupying different niches (i.e., hunting in the air or ground) and demonstrate the importance of performing empirical pilot studies for novel study systems.
Community-in-the-loop: towards pluralistic value creation in AI, or—why AI needs business ethics
Authors: Häußermann Johann Jakob , Lütge Christoph
Published: March 2021

Today, due to growing computing power and the increasing availability of high-quality datasets, artificial intelligence (AI) technologies are entering many areas of our everyday life. Thereby, however, significant ethical concerns arise, including issues of fairness, privacy and human autonomy. By aggregating current concerns and criticisms, we identify five crucial shortcomings of the current debate on the ethics of AI. On the threshold of a third wave of AI ethics, we find that the field eventually fails to take sufficient account of the business context and deep societal value conflicts the use of AI systems may evoke. For even a perfectly fair AI system, regardless of its feasibility, may be ethically problematic, a too narrow focus on the ethical implications of technical systems alone seems insufficient. Therefore, we introduce a business ethics perspective based on the normative theory of contractualism and conceptualise ethical implications as conflicts between values of diverse stakeholders. We argue that such value conflicts can be resolved by an account of deliberative order ethics holding that stakeholders of an economic community deliberate the costs and benefits and agree on rules for acceptable trade-offs when AI systems are employed. This allows AI ethics to consider business practices, to recognise the role of firms, and ethical AI not being at risk to provide a competitive disadvantage or in conflict with the current functioning of economic markets. By introducing deliberative order ethics, we thus seek to do justice to the fundamental normative and political dimensions at the core of AI ethics.
Open vs Endovascular Treatment of Traumatic Peripheral Arterial Injury: Propensity Matched Analysis
Authors: Asmar Samer , Bible Letitia , Obaid Omar , Tang Andrew , Khurrum Muhammad , Castanon Lourdes , Ditillo Michael , Joseph Bellal
Published: March 2021

BACKGROUND:

Arterial injuries occur in the setting of blunt and penetrating trauma. Despite increasing use, there remains a paucity of data comparing long-term outcomes of endovascular vs open repair management of these injuries. The aim of our study was to compare outcomes and readmission rates of open vs endovascular repair of traumatic arterial injuries.

STUDY DESIGN:

The National Readmission Database (2011–2014) was queried for all adult (age ≥ 18 y) patients presenting with peripheral arterial (axillary, brachial, femoral, and popliteal) injuries. Patients were stratified into 2 groups based on intervention: open vs endovascular approach. Propensity score matching (1:2 ratio) was performed. Outcomes measures were complications, length of stay (LOS), 30-day readmission, and cost of readmission.

RESULTS:

A matched cohort of 786 patients was obtained (endovascular: 262, open: 524). Mean age was 45 ± 17 years, and 79% were males. Median LOS was 4 (range 2–6) days for the endovascular group vs 3 (range 2–5) days for the open group (p < 0.01). The endovascular group had higher rates of seroma (4% vs 2%; p = 0.04) and arterial thrombosis (13% vs 7%; p < 0.01) during index hospitalization. Patients who underwent endovascular repair had higher 30-day readmission (11% vs 7%; p = 0.03) and a higher 30-day open-reoperation rate (6% vs 2%; p < 0.01). On subanalysis of the patients who were readmitted, the median cost of each readmission was higher in the endovascular group $47,000 ($27,202–$56,763) compared with $21,000 ($11,889–$43,503) in the open group.

CONCLUSIONS:

Endovascular repair for peripheral arterial injuries was associated with higher rates of in-hospital complications, readmissions, and costs. As this new technology continues to undergo refinement, a thorough re-evaluation of its indications, risks, and benefits is warranted.
African Literature in the Digital Age
Authors: Adenekan Shola
Published: March 2021

The first book-length study on the relationship between African literature and new media.
Diode-pumped, electro-opticallyQ-switched, cryogenic Tm:YAG laser operating at 1.88 μm
Authors: Körner Jörg , Jambunathan Venkatesan , Yue Fangxin , Reiter Jürgen , Slezák Ondřej , Navrátil Petr , David Samuel Paul , Lucianetti Antonio , Hein Joachim , Mocek Tomáš , Kaluza Malte C.
Published: March 2021

We present a diode-pumped, electro-opticallyQ-switched Tm:YAG laser with a cryogenically cooled laser crystal at 120 K. Output pulses of up to 2.55 mJ and 650 ns duration were demonstrated in an activelyQ-switched configuration with a repetition rate of 1 Hz. By using cavity dumping the pulse duration was shortened to 18 ns with only a slightly lower output energy of 2.22 mJ. Furthermore, using a simplified rate equation model, we discuss design constraints on the pump fluence in a pulse pump approach for Tm:YAG to maximize the energy storage capability at a given pump power.
THE DATING OF PHILIPPOS OF AMPHIPOLIS (BNJ 280 T2)
Authors: Arehart Brent
Published: March 2021

On the basis of two neglected testimonia, this short note argues that the terminus ante quem for Philippos of Amphipolis (BNJ 280) should be moved forward to the third century or to the early fourth century c.e. if not earlier.
ANDREW MANGO, Atatürk—The Biography of the Founder of Modern Turkey (London: John Murray, 1999; Woodstock, N.Y.: Overlook Press, 2000). Pp. 687. $40.00 cloth.
Authors: REED HOWARD A.
Published: March 2021

This is the best biography to date of Mustafa Kemal Atatürk. Kemal co-founded the Turkish Republic in 1923 and was its first president until his death in 1938 at age 58. Mango writes that Kemal “believed that the struggle for genuine independence should be waged by each nation for itself in the name of an overarching secular ideal of progress common to all. . . . His aim was not imitation but participation in a universal civilization” (p. xi). Kemal's views derived from those of late Ottoman ideologues—notably Namık Kemal and Ziya Gökalp (authors of significant studies that are not in Mango's bibliography, which, in this reviewer's opinion, would have enhanced his fine work). Kemal was “[a]bove all . . . a builder, the greatest nation-builder of modern times,” writes Mango on the first page of his engagingly written, well-documented book. He concludes that “Atatürk was a competent commander, a shrewd politician, a statesman of supreme realism. But above all he was a man of the Enlightenment. And the Enlightenment was not made by saints” (p. 528).
Antarctic pack ice seal observations during spring across the Lazarev Sea
Authors: Bester Marthán N. , Lübcker Nico , Haddad Wiam , Bornemann Horst , Wege Mia
Published: March 2021

The distribution, density and percentage contribution of pack ice seals during ship-board censuses in the marginal sea ice zone beyond the Lazarev Sea in spring 2019 are presented. Adult/juvenile crabeater seals (n = 19), leopard seals (n = 3) and Ross seals (n = 10) were sighted during 582.2 nm of censuses along the ship’s track line in the area bounded by 00°00’–22°E and 56°–60°S. Antarctic fur seals (n = 21) were only encountered on the outer fringes of the pack ice, and Weddell seals were absent due to their primary use of fast ice and inner pack ice habitats close to the coast. Crabeater seal sightings included juveniles (n = 2) and another four groups of 2–3 unclassified crabeater seals, singletons (n = 5), single mothers with pups (n = 3) and a family group (n = 1 triad). Only one leopard seal attended a pup, while no Ross seal pups were located. The survey was likely of insufficient effort, in both extent (north of 60°S) and duration (18 days), to locate seals in considerable numbers this early (late October/early November) in their austral spring breeding season.
FROM DEAD END TO CENTRAL CITY OF THE WORLD: (RE)LOCATING ROME ON RUSKIN'S MAP OF EUROPE
Authors: Clegg Jeanne
Published: March 2021

The habit of observing and recording carefully, in words and in drawing, the works of God in nature and of man in art made travel essential to the process of continual rediscovery which characterizes the work of John Ruskin, causing him to repeatedly redraw his map of Europe. In 1840–1, the young man's Evangelical upbringing and antipathy for the classical inhibited his response to Rome, which remained peripheral to the monumental volumes of the mid-century. Shifting religious views and studies of ancient myth prepared the way for two revelatory visits to Rome in the early 1870s. In Oxford lectures, Ruskin read in Botticelli's frescoes in the Sistine Chapel syntheses of oppositions between schools of art, between the natural and the spiritual, Greek and Christian cultures, Catholic faith and Reforming energies. He also came to feel the ‘power of the place’ in holy places of early Christianity and in continuities of peasant life. Rome is therefore relocated as ‘the central city of the world’, but modern realities menaced this vision. What had been an impoverished backwater was undergoing massive redevelopment and industrialization as the capital of a newly unified state with international ambitions. From these changes, commented on in his monthly pamphlet, Fors Clavigera, Ruskin extracted severe lessons for Victorian Britain. This article is about the ways in which the two types of change interact.
Recovering authentic global position system L1 signals under spoofing using dual receiver direct positioning
Authors: Sun Chao , Cheong Joon Wayn , Dempster Andrew G. , Zhao Hongbo , Feng Wenquan
Published: March 2021

Spoofing is a kind of deliberate interference that aims to manipulate global navigation satellite system (GNSS) receivers into counterfeit position solutions. Conventional anti-spoofing methods are implemented prior to the calculation of the position solution, depending on the specific spoofing attack mechanisms. The paper presents a spoofing detection and mitigation method implemented in the position domain. The proposed method projects the correlograms of the visible satellites to a position-clock bias domain to construct the position domain projected correlogram. P(Y) code signatures retrieved from a reference station receiver are used to identify the counterfeit position solution and remove it from the victim receiver. Compared with the conventional single-channel spoofing detection technique, the proposed anti-spoofing method is more robust against thermal noise by combining the energy from multiple satellites. Detailed mathematical derivation of the statistical characteristics of this method is presented. Its effectiveness is validated using a realistic dataset generated by a Spirent GNSS simulator and NordNav wideband front-end. Results show that the proposed algorithm is capable of not only detecting a spoofing attack but also removing the spoofing effect from the victim receiver.
Laptop-Administered NIH Toolbox and Cogstate Brief Battery in Community-Dwelling Black Adults: Unexpected Pattern of Cognitive Performance between MCI and Healthy Controls
Authors: Kairys Anson , Daugherty Ana , Kavcic Voyko , Shair Sarah , Persad Carol , Heidebrink Judith , Bhaumik Arijit , Giordani Bruno
Published: March 2021

Objective:

Black adults are approximately twice as likely to develop Alzheimer’s disease (AD) than non-Hispanic Whites and access diagnostic services later in their illness. This dictates the need to develop assessments that are cost-effective, easily administered, and sensitive to preclinical stages of AD, such as mild cognitive impairment (MCI). Two computerized cognitive batteries, NIH Toolbox-Cognition and Cogstate Brief Battery, have been developed. However, utility of these measures for clinical characterization remains only partially determined. We sought to determine the convergent validity of these computerized measures in relation to consensus diagnosis in a sample of MCI and healthy controls (HC).

Method:

Participants were community-dwelling Black adults who completed the neuropsychological battery and other Uniform Data Set (UDS) forms from the AD centers program for consensus diagnosis (HC = 61; MCI = 43) and the NIH Toolbox-Cognition and Cogstate batteries. Discriminant function analysis was used to determine which cognitive tests best differentiated the groups.

Results:

NIH Toolbox crystallized measures, Oral Reading and Picture Vocabulary, were the most sensitive in identifying MCI apart from HC. Secondarily, deficits in memory and executive subtests were also predictive. UDS neuropsychological test analyses showed the expected pattern of memory and executive functioning tests differentiating MCI from HC.

Conclusions:

Contrary to expectation, NIH Toolbox crystallized abilities appeared preferentially sensitive to diagnostic group differences. This study highlights the importance of further research into the validity and clinical utility of computerized neuropsychological tests within ethnic minority populations.
Deep fluids and their role in hydrocarbon migration and oil deposit formation exemplified by supercritical СO2
Authors: LIFSHITS Sara
Published: March 2021

Hydrocarbon migration mechanism into a reservoir is one of the most controversial in oil and gas geology. The research aimed to study the effect of supercritical carbon dioxide (СО2) on the permeability of sedimentary rocks (carbonates, argillite, oil shale), which was assessed by the yield of chloroform extracts and gas permeability (carbonate, argillite) before and after the treatment of rocks with supercritical СО2. An increase in the permeability of dense potentially oil-source rocks has been noted, which is explained by the dissolution of carbonates to bicarbonates due to the high chemical activity of supercritical СО2 and water dissolved in it. Similarly, in geological processes, the introduction of deep supercritical fluid into sedimentary rocks can increase the permeability and, possibly, the porosity of rocks, which will facilitate the primary migration of hydrocarbons and improve the reservoir properties of the rocks. The considered mechanism of hydrocarbon migration in the flow of deep supercritical fluid makes it possible to revise the time and duration of the formation of gas–oil deposits decreasingly, as well as to explain features in the formation of various sources of hydrocarbons and observed inflow of oil into operating and exhausted wells.
Using Comprehensible Input in the Latin Classroom to Enhance Language Proficiency
Authors: Venditti Emanuela
Published: March 2021

This study originates from my curiosity to explore a different Latin teaching approach to address some students’ misconception that Latin is an unnecessarily complicated language that no one speaks anymore.
The Plague of Athens Shedding Light on Modern Struggles with COVID-19
Authors: Malbeuf Jilene , Johnson Peter , Johnson John , Mardon Austin
Published: March 2021

In 2020, we are facing unprecedented times, and as some form of lockdown continues with no signs of ending feelings of hopelessness are completely natural and understandable. Unprecedented times does not mean that these current issues and struggles have never been faced by humanity before, however. The Spanish Flu which took place after World War One and the Black Death that was rampant in Asia and Europe in the 14th century quickly come to mind as examples of past pandemics, but these are only two examples of devastating diseases throughout human history. The Plague of Athens that was raging during the beginning of the Peloponnesian War in 430 BCE is another such example. Though removed from our current situation by many centuries, its symptoms and the effects it had on the population of Athens have been meticulously recorded by the general and historian Thucydides, giving us the opportunity to compare his account to our own experiences today. The disease may be different, and the image he portrays may be more violent and desperate than our own, but nonetheless we can see similarities in how these two separate societies have reacted to unforeseen hardships. In this comparison, we can come to understand at once our own good fortune at going through a pandemic with the support of modern technology and medicine as well as how universal our reactions are to this type of suffering, thereby making it natural rather than shameful. Humanity has faced a great deal of diversity before, and COVID-19 will likely prove to be no different.
A textile workshop to approach Classical civilisation
Authors: Seijas Elena Miramontes
Published: March 2021

Every day teachers try to improve their students’ awareness of how life was in Classical times. We talk about mythology, politics, the building of cities and many other aspects that made the ancient world, but what do we actually know and teach about clothing in ancient times? Our society seems to pay a lot of attention to the physical aspect of the ancient world. We know that clothing and adornment are important ways in which people were defined as a part of a social group, yet our students seem to believe that our ancestors just had a poor selection of national garments to make their identity clear.
Provincia Iudaea: Eliana, Masada, Aelia Capitolina
Authors: LiCalsi Lynn
Published: March 2021

Provincia Iudaea is a supplementary reader for beginning and intermediate Latin students. It includes three stories set in first-century Judaea. The stories explain the confrontation between Romans and Jews at this time. The first story unfolds through the eyes of the main character, a young Jewish girl named Eliana. After the destruction of the Second Temple in 70 CE, Eliana and her mother escape to Masada. Many years later, 132 CE, another character, Naomi, completes the narrative about the final struggle between Romans and Jews during the Bar Kochba Revolt. The book concludes with Hadrian's proclamations. Illustrations abound in this reader, giving students an anchor for understanding the narrative. Vocabulary is provided on facing pages so that students can read without the burden of looking up words. Some words appear in the dictionary entry format, whereas others are simply glossed. The reason for this is not to burden students with grammatical details
Maternal and Perinatal Factors Associated With Twin Pregnancies in Ecuador
Authors: Orozco-Quinga Ximena , González-Andrade Fabricio
Published: March 2021

There are few studies on twins in Ecuador and Latin America. It requires a better understanding of perinatal conditions, especially from an ethnic perspective. This work aims to assess perinatal factors related to twin pregnancy in Ecuadorian Mestizo individuals. We performed an epidemiological, observational and cross-sectional study at the Hospital San Francisco and Hospital Nueva Aurora in Quito, Ecuador, from November 2019 to January 2020. It included 203 newborns from twin pregnancies, including mothers with and without pathological history. The average gestational age was 31 weeks, and the APGAR score at first minute was 6.86, with significant differences. Regarding the metabolic balance, the mean pH was 6.14; and bicarbonate was 11.57, with significant differences. Twins had intrauterine growth restriction in 6.9% of cases, with significant differences (p = .003); 81.4% required supplemental oxygen, with significant differences (p = .002); 93% required noninvasive mechanical ventilation (NIMV), with significant differences (p = . 003); 93% required inotropic and sedation, with substantial differences; 69% required antibiotics (≥21 days), with significant differences (p = .014); and 17.2% needed between 8 to 14 days of hospitalization, and 51% more than 28 days, with significant differences. The studied mothers’ demographic profile was mostly Mestizos, with an average age of 32 years, and 93% had a poverty status. Most of the twins were diamniotic monochorial and were discordant twins. It found jaundice, premature anemia and sepsis in 100% of twins and hyaline membrane disease in 89.66% of twins. Twins of women with relevant prenatal care had more premature births (30.4 ± 2.6 weeks), more acid−base imbalance, APGAR at ≥7 min in 90% of cases, and patent ductus arteriosus in all. There was also a greater need for double intensive phototherapy than twins of healthy women.
Time Dependent Mechanical Crack Closure as a Potential Rapid Source of Post‐Seismic Wave Speed Recovery: Insights From Experiments in Carrara Marble
Authors: Meyer Gabriel G. , Brantut Nicolas , Mitchell Thomas M. , Meredith Philip G. , Plümper Oliver
Published: March 2021

Seismological observations indicate strong variations in wave velocities around faults both co‐seismically during earthquakes, and post‐seismically. Recovery is commonly associated with a reduction in crack damage. Here, we explore the recovery associated with time‐dependent mechanical closure of cracks. We report results from laboratory experiments conducted on dry cores of Carrara marble at room temperature. We deformed cylindrical samples in the semi‐brittle regime to induce crack damage before subjecting them to hydrostatic and triaxial stress conditions for extended periods of time while recording dilatancy and wave speeds repeatedly. We report wave speed increases of up to 40% of the damage‐induced wave speed drop in samples subject to hydrostatic loading. Moreover, we report the occurrence of significant wave speed increases contemporaneously with time‐dependent creep in triaxially loaded samples. Wave speed recovery during creep is only observed below a threshold creep strain rate, a result we interpret as a transition from brittle to plastic creep with decreasing strain rate. We interpret the wave speed increase in terms of reduced crack density and increased contact area within the crack array, and show that around 40% of the total crack surface has to be closed to justify the observed wave speed recoveries. We propose that mechanical crack closure is driven by the viscous relaxation of the bulk rock under the influence of locked‐in stresses at low confining pressure, and of the external stresses at higher confining pressure. Our study shows that mechanical crack closure is a significant source of time‐dependent wave speed recovery.
Three‐Dimensional Simulation of Shoaling Internal Solitary Waves and Their Influence on Particle Transport in the Southern Red Sea
Authors: Guo Daquan , Zhan Peng , Hoteit Ibrahim
Published: March 2021

The shoaling process of a group of internal solitary waves (ISWs) in the southern Red Sea is simulated with a three dimensional, nonhydrostatic, high‐resolution MIT general circulation model. The breaking and dissipation processes are well reproduced, in which a positive tail forms behind and locally moves the interface upward, causing the transformation of wave polarity as it moves onshore. With the step‐like structure followed, the wave eventually evolves into smaller water bores. Combined with the parameters of the leading wave slope (Sw) of about 0.07 and topography slope (S) of about 0.01, the shoaling is suggested to follow a mild breaking process. The particle transport during the shoaling process is further examined quantitatively using the Connectivity modeling system (CMS). About 38,400 particles are released at six different vertical layers in the main shoaling domain. Most of the particles are transported up‐and‐down following the wave oscillation process then settle within 10–20 m around the original released depth. For the particles inside the breaking area, the oscillation process becomes more complex and intensified, and eventually a great portion of these particles settle far away from their released locations. The time‐integrated transport distance, Ti, and the direct transport distance, Ts, are also analyzed. With Ti almost 20 times to Ts in vertical, continuous up‐and‐down movements are suggested during the shoaling process.
Under Ice and Early Summer Phytoplankton Dynamics in Two Arctic Lakes with Differing DOC
Authors: Hazuková V. , Burpee B. T. , McFarlane‐Wilson I. , Saros J. E.
Published: March 2021

We investigated Arctic lake phytoplankton response along vertical gradients in the water column during seasonal succession from ice‐covered to open‐water conditions. Two oligotrophic lakes in West Greenland with different dissolved organic carbon (DOC) concentrations were selected. We assessed which factors: (1) promote under‐ice growth of phytoplankton, and (2) trigger shifts in the community structure. Our results suggest that DOC is an important driver of the seasonal distribution of phytoplankton biomass—high DOC exacerbates light limitation under ice resulting in low phytoplankton biomass, but supports phytoplankton growth during the open‐water period when photolytic and biological degradation of organic matter contributes to the pool of available nutrients. Under‐ice phytoplankton biomass in a clear, low DOC lake was as high as during the open‐water period, suggesting the importance of under‐ice processes for lake metabolic balance, also evidenced by persistent oxic conditions in the hypolimnion. Species composition was dynamic, reflecting rapidly changing conditions over the course of the season. Our data suggest that phytoplankton under ice provides seed populations for early spring blooms and that the largest shifts in species composition occur later during the summer, likely as a result of nutrient depletion and intensified grazing pressure. Early spring temperatures in West Greenland have risen rapidly in recent decades, triggering shifts in the timing of lake ice‐out and the onset of stratification; therefore, it is important to understand phytoplankton seasonal dynamics to disentangle the effects of climate‐driven shifts on aquatic biota.
Influence of Irrigation Drivers Using Boosted Regression Trees: Kansas High Plains
Authors: Lamb Susan E. , Haacker Erin M. K. , Smidt Samuel J.
Published: March 2021

Groundwater levels across parts of western Kansas have been declining at unsustainable rates due to pumping for agricultural irrigation despite water‐saving efforts. Accelerating this decline is the complex agricultural landscape, consisting of both categorical (e.g., management boundaries) and numerical (e.g., crop prices) factors that drive irrigation decisions, making integrated water budget management a challenge. Furthermore, these factors frequently change through time, rendering management strategies outdated within relatively short time scales. This study uses boosted regression trees to simultaneously analyze categorical and numerical data against annual irrigation pumping to determine the relative influence of each factor on groundwater pumping across both space and time. In all, 45 key water use variables covering approximately 19,000 groundwater wells were tested against irrigation pumping from 2006 to 2016 across five categories: (1) management/policy, (2) hydrology, (3) weather, (4) land/agriculture, and (5) economics. Study results showed that variables from all five categories were included among the top 10 drivers to irrigation, and the greatest influence came from variables such as irrigated area per well, saturated thickness, soil permeability, summer precipitation, and pumping costs (depth to water table). Variables that had little influence included regional management boundaries and irrigation technology. The results of this study are further used to target the factors that statistically lead to the greatest volumes of groundwater pumping to help develop robust management strategy suggestions and achieve water management goals of the region.
Cold Curriculum for a Hot Topic
Authors: Averett Nancy
Published: March 2021

Educators at ice core labs teach students hands-on lessons about climate change.
The AP-1 transcription factors c-Jun and JunB are essential for CD8α conventional dendritic cell identity
Authors: Novoszel Philipp , Drobits Barbara , Holcmann Martin , Fernandes Cristiano De Sa , Tschismarov Roland , Derdak Sophia , Decker Thomas , Wagner Erwin F. , Sibilia Maria
Published: March 2021

Dendritic cell (DC) development is orchestrated by lineage-determining transcription factors (TFs). Although, members of the activator-protein-1 (AP-1) family, including Batf3, have been implicated in conventional (c)DC specification, the role of Jun proteins is poorly understood. Here, we identified c-Jun and JunB as essential for cDC1 fate specification and function. In mice, Jun proteins regulate extrinsic and intrinsic pathways, which control CD8α cDC1 diversification, whereas CD103 cDC1 development is unaffected. The loss of c-Jun and JunB in DC progenitors diminishes the CD8α cDC1 pool and thus confers resistance to Listeria monocytogenes infection. Their absence in CD8α cDC1 results in impaired TLR triggering and antigen cross-presentation. Both TFs are required for the maintenance of the CD8α cDC1 subset and suppression of cDC2 identity on a transcriptional and phenotypic level. Taken together, these results demonstrate the essential role of c-Jun and JunB in CD8α cDC1 diversification, function, and maintenance of their identity.
Mechanism of substrate transport and inhibition of the human LAT1-4F2hc amino acid transporter
Authors: Yan Renhong , Li Yaning , Müller Jennifer , Zhang Yuanyuan , Singer Simon , Xia Lu , Zhong Xinyue , Gertsch Jürg , Altmann Karl-Heinz , Zhou Qiang
Published: March 2021

LAT1 (SLC7A5) is one of the representative light chain proteins of heteromeric amino acid transporters, forming a heterodimer with its heavy chain partner 4F2hc (SLC3A2). LAT1 is overexpressed in many types of tumors and mediates the transfer of drugs and hormones across the blood-brain barrier. Thus, LAT1 is considered as a drug target for cancer treatment and may be exploited for drug delivery into the brain. Here, we synthesized three potent inhibitors of human LAT1, which inhibit transport of leucine with IC50 values between 100 and 250 nM, and solved the cryo-EM structures of the corresponding LAT1-4F2hc complexes with these inhibitors bound at resolution of up to 2.7 or 2.8 Å. The protein assumes an outward-facing occluded conformation, with the inhibitors bound in the classical substrate binding pocket, but with their tails wedged between the substrate binding site and TM10 of LAT1. We also solved the complex structure of LAT1-4F2hc with 3,5-diiodo-l-tyrosine (Diiodo-Tyr) at 3.4 Å overall resolution, which revealed a different inhibition mechanism and might represent an intermediate conformation between the outward-facing occluded state mentioned above and the outward-open state. To our knowledge, this is the first time that the outward-facing conformation is revealed for the HAT family. Our results unveil more important insights into the working mechanisms of HATs and provide a structural basis for future drug design.
WOODIV, a database of occurrences, functional traits, and phylogenetic data for all Euro-Mediterranean trees
Authors: Monnet Anne-Christine , Cilleros Kévin , Médail Frédéric , Albassatneh Marwan Cheikh , Arroyo Juan , Bacchetta Gianluigi , Bagnoli Francesca , Barina Zoltán , Cartereau Manuel , Casajus Nicolas , Dimopoulos Panayotis , Domina Gianniantonio , Doxa Aggeliki , Escudero Marcial , Fady Bruno , Hampe Arndt , Matevski Vlado , Misfud Stephen , Nikolic Toni , Pavon Daniel , Roig Anne , Barea Estefania Santos , Spanu Ilaria , Strid Arne , Vendramin Giovanni Giuseppe , Leriche Agathe
Published: March 2021

Trees play a key role in the structure and function of many ecosystems worldwide. In the Mediterranean Basin, forests cover approximately 22% of the total land area hosting a large number of endemics (46 species). Despite its particularities and vulnerability, the biodiversity of Mediterranean trees is not well known at the taxonomic, spatial, functional, and genetic levels required for conservation applications. The WOODIV database fills this gap by providing reliable occurrences, four functional traits (plant height, seed mass, wood density, and specific leaf area), and sequences from three DNA-regions (rbcL,matK, andtrnH-psbA), together with modelled occurrences and a phylogeny for all 210 Euro-Mediterranean tree species. We compiled, homogenized, and verified occurrence data from sparse datasets and collated them on an INSPIRE-compliant 10 × 10 km grid. We also gathered functional trait and genetic data, filling existing gaps where possible. The WOODIV database can benefit macroecological studies in the fields of conservation, biogeography, and community ecology.
Erianthridin suppresses non-small-cell lung cancer cell metastasis through inhibition of Akt/mTOR/p70S6K signaling pathway
Authors: Pothongsrisit Sutthaorn , Arunrungvichian Kuntarat , Hayakawa Yoshihiro , Sritularak Boonchoo , Mangmool Supachoke , Pongrakhananon Varisa
Published: March 2021

Cancer metastasis is a major cause of the high mortality rate in lung cancer patients. The cytoskeletal rearrangement and degradation of extracellular matrix are required to facilitate cell migration and invasion and the suppression of these behaviors is an intriguing approach to minimize cancer metastasis. Even though Erianthridin (ETD), a phenolic compound isolated from the Thai orchidDendrobium formosumexhibits various biological activities, the molecular mechanism of ETD for anti-cancer activity is unclear. In this study, we found that noncytotoxic concentrations of ETD (≤ 50 μM) were able to significantly inhibit cell migration and invasion via disruption of actin stress fibers and lamellipodia formation. The expression of matrix metalloproteinase-2 (MMP-2) and MMP-9 was markedly downregulated in a dose-dependent manner after ETD treatment. Mechanistic studies revealed that protein kinase B (Akt) and its downstream effectors mammalian target of rapamycin (mTOR) and p70 S6 kinase (p70S6K) were strongly attenuated. An in silico study further demonstrated that ETD binds to the protein kinase domain of Akt with both hydrogen bonding and van der Waals interactions. In addition, an in vivo tail vein injection metastasis study demonstrated a significant effect of ETD on the suppression of lung cancer cell metastasis. This study provides preclinical information regarding ETD, which exhibits promising antimetastatic activity against non-small-cell lung cancer through Akt/mTOR/p70S6K-induced actin reorganization and MMPs expression.
Computational characterization of inhaled droplet transport to the nasopharynx
Authors: Basu Saikat
Published: March 2021

How human respiratory physiology and the transport phenomena associated with inhaled airflow in the upper airway proceed to impact transmission of SARS-CoV-2, leading to the initial infection, stays an open question. An answer can help determine the susceptibility of an individual on exposure to a COVID-2019 carrier and can also provide a preliminary projection of the still-unknown infectious dose for the disease. Computational fluid mechanics enabled tracking of respiratory transport in medical imaging-based anatomic domains shows that the regional deposition of virus-laden inhaled droplets at the initial nasopharyngeal infection site peaks for the droplet size range of approximately 2.5–19 $$\upmu $$
μ
. Through integrating the numerical findings on inhaled transmission with sputum assessment data from hospitalized COVID-19 patients and earlier measurements of ejecta size distribution generated during regular speech, this study further reveals that the number of virions that may go on to establish the SARS-CoV-2 infection in a subject could merely be in the order of hundreds.
Neural encoding of voice pitch and formant structure at birth as revealed by frequency-following responses
Authors: Arenillas-Alcón Sonia , Costa-Faidella Jordi , Ribas-Prats Teresa , Gómez-Roig María Dolores , Escera Carles
Published: March 2021

Detailed neural encoding of voice pitch and formant structure plays a crucial role in speech perception, and is of key importance for an appropriate acquisition of the phonetic repertoire in infants since birth. However, the extent to what newborns are capable of extracting pitch and formant structure information from the temporal envelope and the temporal fine structure of speech sounds, respectively, remains unclear. Here, we recorded the frequency-following response (FFR) elicited by a novel two-vowel, rising-pitch-ending stimulus to simultaneously characterize voice pitch and formant structure encoding accuracy in a sample of neonates and adults. Data revealed that newborns tracked changes in voice pitch reliably and no differently than adults, but exhibited weaker signatures of formant structure encoding, particularly at higher formant frequency ranges. Thus, our results indicate a well-developed encoding of voice pitch at birth, while formant structure representation is maturing in a frequency-dependent manner. Furthermore, we demonstrate the feasibility to assess voice pitch and formant structure encoding within clinical evaluation times in a hospital setting, and suggest the possibility to use this novel stimulus as a tool for longitudinal developmental studies of the auditory system.
Selective time-dependent changes in activity and cell-specific gene expression in human postmortem brain
Authors: Dachet Fabien , Brown James B. , Valyi-Nagy Tibor , Narayan Kunwar D. , Serafini Anna , Boley Nathan , Gingeras Thomas R. , Celniker Susan E. , Mohapatra Gayatry , Loeb Jeffrey A.
Published: March 2021

As a means to understand human neuropsychiatric disorders from human brain samples, we compared the transcription patterns and histological features of postmortem brain to fresh human neocortex isolated immediately following surgical removal. Compared to a number of neuropsychiatric disease-associated postmortem transcriptomes, the fresh human brain transcriptome had an entirely unique transcriptional pattern. To understand this difference, we measured genome-wide transcription as a function of time after fresh tissue removal to mimic the postmortem interval. Within a few hours, a selective reduction in the number of neuronal activity-dependent transcripts occurred with relative preservation of housekeeping genes commonly used as a reference for RNA normalization. Gene clustering indicated a rapid reduction in neuronal gene expression with a reciprocal time-dependent increase in astroglial and microglial gene expression that continued to increase for at least 24 h after tissue resection. Predicted transcriptional changes were confirmed histologically on the same tissue demonstrating that while neurons were degenerating, glial cells underwent an outgrowth of their processes. The rapid loss of neuronal genes and reciprocal expression of glial genes highlights highly dynamic transcriptional and cellular changes that occur during the postmortem interval. Understanding these time-dependent changes in gene expression in post mortem brain samples is critical for the interpretation of research studies on human brain disorders.
Localized electronic vacancy level and its effect on the properties of doped manganites
Authors: Juan Dilson , Pruneda Miguel , Ferrari Valeria
Published: March 2021

Oxygen vacancies are common to most metal oxides and usually play a crucial role in determining the properties of the host material. In this work, we perform ab initio calculations to study the influence of vacancies in doped manganites $$\text {La}_{(1-\text {x})} \text {Sr}_{\text {x}} \text {MnO}_{3}$$

La

(
1
-
x
)

Sr
x

MnO
3

, varying both the vacancy concentration and the chemical composition within the ferromagnetic-metallic range ($$0.2\,<\,\text {x}\,<\,0.5$$

0.2

<

x

<

0.5

). We find that oxygen vacancies give rise to a localized electronic level and analyse the effects that the possible occupation of this defect state can have on the physical properties of the host. In particular, we observe a substantial reduction of the exchange energy that favors spin-flipped configurations (local antiferromagnetism), which correlate with the weakening of the double-exchange interaction, the deterioration of the metallicity, and the degradation of ferromagnetism in reduced samples. In agreement with previous studies, vacancies give rise to a lattice expansion when the defect level is unoccupied. However, our calculations suggest that under low Sr concentrations the defect level can be populated, which conversely results in a local reduction of the lattice parameter. Although the exact energy position of this defect level is sensitive to the details of the electronic interactions, we argue that it is not far from the Fermi energy for optimally doped manganites ($$\text {x}\,\sim \,1/3$$

x

∼

1
/
3

), and thus its occupation could be tuned by controlling the number of available electrons, either with chemical doping or gating. Our results could have important implications for engineering the electronic properties of thin films in oxide compounds.
A high-efficiency Klebsiella variicola H12-CMC-FeS@biochar for chromium removal from aqueous solution
Authors: Yu Runlan , Man Meilian , Yu Zhaojing , Wu Xueling , Shen Li , Liu Yuandong , Li Jiaokun , Xia Mingchen , Zeng Weimin
Published: March 2021

In polluted groundwater, surface water, and industrial sites, chromium is found as one of the most common heavy metals, and one of the 20 main pollutants in China, which poses a great threat to the ecological environment and human health. Combining biological and chemical materials to treat groundwater contaminated by heavy metals is a promising restoration technology. In this research, Klebsiella variicola H12 (abbreviated as K. variicola) was found to have Cr(VI) reduction ability. A high-efficiency Klebsiella variicola H12-carboxymethyl cellulose (abbreviated as CMC)-FeS@biochar system was established for Cr(VI) removal from aqueous solution. The Scanning Electron Microscope-Energy Dispersive Spectrometer (SEM–EDS), X-ray photoelectron spectroscopy (XPS) results indicated that CMC-FeS was successfully loaded onto the surface of biochar, and K. variicola H12 grew well in the presence of CMC-FeS@biochar with microbial biomass up to 4.8 × 108 cells mL−1. Cr(VI) removal rate of CMC-FeS@biochar system, K. variicola H12 system and K. variicola H12 + CMC-FeS@biochar system were 61.8%, 82.2% and 96.6% respectively. This study demonstrated K. variicola H12-CMC-FeS@biochar system have potential value for efficient removal of Cr(VI) from Cr(VI)-polluted groundwater.
Serum artemin is not correlated with sensitivity within dogs with naturally occurring osteoarthritis pain
Authors: Gupta Ankita , Chiavaccini Ludovica , Minnema Laura M. , Chiu King Wa , Knazovicky David , Hash Jonathan A. , Mishra Santosh K. , Lascelles B. Duncan X.
Published: March 2021

Osteoarthritis (OA) pain is associated with peripheral and central sensitization in humans and results in widespread increased sensitivity across the body. Sensitization contributes to the OA-associated pain (OAP) state. We recently identified increased levels of an endogenous neurotrophic factor, artemin (ARTN), in dogs with OAP compared to healthy pain-free controls. Circulating ARTN released from damaged tissues in OA, may play a central role in widespread sensitivity and pain. However, the relationship between ARTN and somatosensory sensitivity remains unknown. The study aimed to assess the relationship between serum ARTN concentrations and measures of sensitivity in dogs with OAP using quantitative sensory testing. We hypothesized that there would be a positive association between circulating ARTN and increased sensitivity to mechanical and thermal stimuli in dogs with OAP. We used linear and logistic regression models to assess the relationship between ARTN, sensitization, and pain within a cohort of 43 dogs with spontaneous OAP. Serum ARTN was not associated with the degree of sensitization within dogs with OAP. Further, across dogs with varying OAP severity, we did not find any association between ARTN, and clinical measures of joint pain and disability. Although a relationship between ARTN and joint pain was not ruled out.