bluuebunny/crossref_metadata_2025 huggingface dataset:
Waterlogging tolerance of grass pea (Lathyrus sativus L.) at germination related to country of origin
Authors: Wiraguna Edi , Malik Al Imran , Colmer Timothy David , Erskine William
Published: December 2020

Grass pea (Lathyrus sativus L.) has a Mediterranean origin and was spread to Western Europe, Africa and South Asia. Over time, this grain legume crop has become important in South Asia, where it is often affected by waterlogging at germination. Therefore, varieties with waterlogging tolerance of seeds at germination are needed. This study evaluated waterlogging tolerance in a grass pea diversity panel. First, morpho-agronomic traits of 53 grass pea genotypes from 7 diverse countries (Afghanistan, Australia, Bangladesh, Cyprus, Ethiopia, Greece and Pakistan) were measured in a glasshouse. Seeds of the collection were then sown into waterlogged soil for 6 days and is subsequently drained for 8 days. Finally, representative genotypes from each country of origin of the three survival patterns (described below) were then tested to identify the effect of seed priming on germination and seedling growth in waterlogged soil. Canonical analysis of six traits (seed weight, pod length, pod width, flowering time, time to maturity and seedling survival) showed that genotypes from Bangladesh and Ethiopia were similar. There was a significant variation amongst genotypes in waterlogging tolerance. Genotypes from Bangladesh and Ethiopia showed the highest percent seedling survival (54% and 47%), with an ability to germinate under waterlogging and then maintain growth from the first day of draining to the final sampling (Pattern 1). In contrast, genotypes from other origins either germinated during waterlogging, but did not survive during drainage (Pattern 2) or failed to germinate and had low seedling survival during waterlogging and drainage (Pattern 3). Priming seeds reduced seedling survival in grass pea. Despite Mediterranean origin, specific ecotypes of grass pea with greater waterlogging tolerance under warm wet conditions have been favoured in Bangladesh and Ethiopia where adaptation to extreme precipitation events at germination and seedling survival upon soil drainage is critical for successful crops.
On the nature of the lexicon: The status of rich lexical meanings
Authors: HOGEWEG LOTTE , VICENTE AGUSTIN
Published: December 2020

Both in linguistics and in psycholinguistics there is some debate about how rich or thin lexico-semantic representations are. Traditionally, in formal semantics but also in philosophy of language as well as in cognitive pragmatics, lexical meanings have been thought to be simple stable denotations or functions. In this paper, we present and discuss a number of interpretational phenomena of which the analysis proposed in the literature makes crucial use of rich meanings. The phenomena in question are cases where the assignment of truth-conditional contents to utterances seems to follow rules that do not operate on simple stable denotations or any other kind of ‘thin’ meanings but where composition takes rich structured representations as input. We also discuss problems for such accounts, which are mostly based on the inability of extant rich meanings accounts to explain many other interpretational phenomena, and we discuss the solutions that have been proposed to solve them. Furthermore, we address the discussion whether the informationally rich meanings are part of semantics, and more specifically part of the lexicon, or whether this information should be ascribed to more general world knowledge.
Dependence of fishbone cycle on energetic particle intensity in EAST low-magnetic-shear plasmas
Authors: Zhu Xiang , Zeng Long , Qiu Zhiyong , Hao Baolong , Shen Wei , Gu Xiang , Wu Muquan , Tang Tian , Qian Jinping , Liu Haiqing , Jiang Di , Xu Liqing , Zhang Jizong , Liu Yong , Zang Qing , Jie Yinxian , Gao Xiang , Lin Xiaodong
Published: December 2020

The dependence of fishbone cycle on energetic particle intensity has been investigated in EAST low-magnetic-shear plasmas. It is observed that the fishbone mode growth rate, saturation amplitude as well as fishbone cycle frequency clearly increase with increasing neutral beam injection (NBI) power. Moreover, enhanced electron density and temperature perturbations as well as energetic particle loss were observed with greater injected NBI power. Simulation results using M3D-K code show that as the NBI power increases, the resonant frequency and the energy of the resonant particles become higher, and the saturation amplitude of the mode also changes, due to the non-perturbative energetic particle contribution. The relationship between the calculated energetic particle pressure ratio and fishbone cycle frequency is obtained as

${f_{\textrm{FC}}} = 2.2{(1000{\beta _{\textrm{ep,calc}}} - 0.1)^{5.9 \pm 0.5}}$

. Results consistent with the experimental observations have been achieved based on a predator–prey model.
Species composition and habitat preferences of benthic ostracod and foraminifera in seagrass and non-seagrass systems within a tropical estuary
Authors: Raynusha Chandran , Rozaimi Mohammad , Omar Ramlan , Faiz Noraswana Nor , Hesan Nur Munirah , Hanis Syarifah Nor , Abdullah Siti Aisyah , Izzati Eizyan
Published: December 2020

Ostracods and foraminifera are excellent indicators of environmental change and can act as proxies for the presence of seagrass meadows. These proxies have been under-utilized in vulnerable coastal ecosystems in South-east Asia, and the fundamental habitat and environmental parameters required for such application in environmental monitoring have not yet been established. We investigated the habitat preferences of ostracods and foraminiferal species in seagrass and non-seagrass habitats within Sungai Pulai Estuary (Johor, Malaysia), a system currently undergoing major coastal changes. Samples consisted of surficial and downcore sediments collected from two seagrass meadows and a non-seagrass habitat. Multivariate analysis determined the variations in spatial and depth distribution of the meiofauna. Species dominance, abundance and distribution varied between sites, whereas diversity and community structure varied with sediment depth. We found fewer ostracod individuals (N = 1133) than foraminifera (N = 7242). Ostracods were more species-diverse (H′ = 3.34) in the non-vegetated area compared with seagrass areas (H′ = 2.74), whereas foraminifera species were most diverse (H′ = 3.60) in seagrass areas. Opportunistic species, such as Loxoconcha lilljeborgii, Asterorotalia pulchella, Murrayinella globosa, Ammonia tepida and Elphidium neosimplex dominated the meiofaunal assemblages. The presence of Nummulitidae and Paracyprididae in downcore samples provided information related to rare species and families. Salinity, organic matter and percentage of sand explained much of the meiofaunal distribution. Our findings provide new insight into the factors influencing the presence and distribution of ostracods and foraminifera in the estuary, comprising baseline information for understanding the vulnerability of such habitats to anthropogenic changes.
Downward transfer of support and care: understanding the cultural lag in rural China
Authors: Qiu F. X. , Zhan H. J. , Liu J. , Barrett P. M.
Published: December 2020

The Chinese culture of filial piety has historically emphasised children's responsibility for their ageing parents. Little is understood regarding the inverse: parents’ responsibility and care for their adult children. This paper uses interviews with 50 families living in rural China's Anhui Province to understand intergenerational support in rural China. Findings indicate that parents in rural China take on large financial burdens in order to sustain patrilineal traditions by providing housing and child care for their adult sons. These expectations lead some rural elders to become migrant workers in order to support their adult sons while others provide live-in grandchild-care, moving into their children's urban homes or bringing grandchildren into their own homes. As the oldest rural generations begin to require ageing care of their own, migrant children are unable to provide the sustained care and support expected within the cultural tradition of xiao. This paper adds to the small body of literature that examines the downward transfer of support from parents to their adult children in rural China. The authors argue that there is an emerging cultural rupture in the practice of filial piety – while the older generation is fulfilling their obligations of upbringing and paying for adult children's housing and child care; these adult children are not necessarily available or committed to the return of care for their ageing parents. The authors reveal cultural and structural lags that leave millions of rural ageing adults vulnerable in the process of urbanisation in rural China.
Qualitative comparative analysis of health economic evaluation guidelines for health technology assessment in European countries
Authors: Zisis Konstantinos , Naoum Panagiota , Athanasakis Kostas
Published: December 2020

Objective

To classify, analyze, and compare published guidelines for economic evaluation within health technology assessment (HTA) in European countries and highlight differences and similarities.

Methods

We performed a literature review to identify published guidance for the conduct and assessment of economic evaluation studies that are undertaken within the context of HTA processes in European countries. Organizations and working groups were identified via the ISPOR, INAHTA, and EUnetHTA databases. Following the identification of official documents, we performed a qualitative content analysis to highlight discrepancies or common practices under the following categories: comparator, perspective on costs/benefits, time horizon, economic evaluation method, instrument used for utility measurement, outcome measure, source for efficacy, modeling, sensitivity analysis, discounting, and incremental cost-effectiveness ratio.

Results

A total of nineteen guidance documents were identified (in English) providing data for the analysis in nineteen countries. The comparative content analysis identified common practices in most countries regarding the approaches to the choice of comparator, source of data, the preferred economic evaluation method, the option for a lifetime analytical horizon, discounting, and the choice of key outcome measure—for which, most countries recommend the use of the EQ-5D instrument. Differences were mainly found in the choice of perspective, dealing with uncertainty and sensitivity analysis, the use of end points, and the required use of modeling.

Conclusions

The use of economic evaluation constitutes one of the key pillars of the HTA process in Europe. Although a methodological convergence has occurred during the last few years, notable differences still remain.
‘Evidence for waterborne origin of an extended mixed gastroenteritis outbreak in a town in Northern Greece, 2019’
Authors: Tzani M. , Mellou K. , Kyritsi M. , Kolokythopoulou F. , Vontas A. , Sideroglou T. , Chrysostomou A. , Mandilara G. D. , Tryfinopoulou K. , Georgakopoulou T. , Hadjichristodoulou C.
Published: December 2020

We investigated a large gastroenteritis outbreak that occurred in Northern Greece in 2019. A case was defined as anyone presenting with diarrhoea and/or vomiting from 24 January 2019 to 04 February 2019. We conducted a case-control study (CCS) using random selection of participants >16 years of age, residents of town X, who visited the health care centre between 25 and 28 January 2019. Moreover, we conducted a retrospective cohort study (CS) at the four elementary schools of the town. We collected clinical and water samples and the water supply system was inspected. In total, we recorded 638 cases (53% female; median age was 44 years (range 0–93)). Forty-eight cases and 52 controls participated in the CCS and 236 students in the CS. Both CCS and CS indicated tap water as the most likely source (OR 10, 95% CI 2.09–93.4, explaining 95.7% of cases; RR = 2.22, 95% CI 1.42–3.46, respectively). More than one pathogen was detected from stool samples of 6 of the 11 cases tested (norovirus, Campylobacter jejuni, Enterohemorrhagic E. coli (EHEC) and Enteropathogenic E. coli (EPEC)). Water samples, collected after ad-hoc chlorination, tested negative. Technical failures of the water tanks' status were identified. Our results suggested a waterborne outbreak. We recommended regular monitoring of the water supply system and immediate repair of technical failures.
Morphologically conditioned phonology with two triggers
Authors: Sande Hannah
Published: December 2020

Morphologically conditioned phonology, where a particular phonological alternation or requirement holds only for a subset of lexical items or in a subset of morphological contexts, is well documented. This paper expands on the literature by examining phonological alternations where two independent triggering morphemes must both be present for a phonological alternation to apply. Several cases of doubly morphologically conditioned phonological alternations, from a diverse set of languages, are described. The existence of morphologically conditioned phonology with two triggers informs our models of the interface between morphology and phonology, in that phonological operations must be able to reference the presence of more than one morpheme simultaneously. A range of possible analyses are considered, including those set in Stratal OT, Indexed Constraint Theory, Cophonology Theory and Cophonologies by Phase Theory. A Cophonologies by Phase account is found to be optimal, where multiple morpheme-specific phonological requirements accumulate and co-trigger alternations within a single spell-out domain.
The effect of Celiac disease on cardiac functions and aortic elasticity parameters in children
Authors: Alkan Fatos , Dogan Guzide , Kasırga Erhun , Coskun Senol
Published: December 2020

Aim:

We aimed to investigate the effect of Celiac disease on myocardial functions and aortic elasticity parameters.

Materials and Methods:

Thirty children with Celiac disease and 30 healthy children were enrolled in the study. Both the groups were similar in terms of age and gender. Cardiac functions of all children in the patients and control group were evaluated using conventional transthoracic echocardiography and tissue Doppler imaging. Aortic strain, distensibility, and stiffness index were calculated by M-mode echocardiography.

Results:

The demographic findings, height, weight, and body mass index of cases were similar among two groups. No statistical difference was found between E wave velocity for conventional transthoracic echocardiography and tissue Doppler imaging measurements of the mitral valve; early diastolic flow peak velocity, A wave velocity; late diastolic flow peak velocity; and E/A ratio. Isovolumetric relaxation time and isovolumetric contraction time ratios were statistically different between the groups (p = 0.000, p = 0.000, p = 0.000). The myocardial performance index calculated according to the pulse Doppler measurement results was found to be statistically different between the groups (p = 0.000). There was no statistical difference between the groups in terms of aortic strain, distensibility, and stiffness index.

Conclusion:

In this study, both conventional transthoracic echocardiography and tissue Doppler imaging revealed the affection of the myocardial functions during systole and diastole in children with Celiac disease. Therefore, early follow-up and routine cardiac evaluation of celiac patients may be appropriate due to the increased risk of cardiac affection.
A New Spin on Spatial Cognition in ADHD: A Diffusion Model Decomposition of Mental Rotation
Authors: Feldman Jason S. , Huang-Pollock Cynthia
Published: December 2020

Objectives:

Multiple studies have found evidence of task non-specific slow drift rate in ADHD, and slow drift rate has rapidly become one of the most visible cognitive hallmarks of the disorder. In this study, we use the diffusion model to determine whether atypicalities in visuospatial cognitive processing exist independently of slow drift rate.

Methods:

Eight- to twelve-year-old children with (n= 207) and without ADHD (n= 99) completed a 144-trial mental rotation task.

Results:

Performance of children with ADHD was less accurate and more variable than non-ADHD controls, but there were no group differences in mean response time. Drift rate was slower, but nondecision time was faster for children with ADHD. A Rotation × ADHD interaction for boundary separation was also found in which children with ADHD did not strategically adjust their response thresholds to the same degree as non-ADHD controls. However, the Rotation × ADHD interaction was not significant for nondecision time, which would have been the primary indicator of a specific deficit in mental rotationper se.

Conclusions:

Poorer performance on the mental rotation task was due to slow rate of evidence accumulation, as well as relative inflexibility in adjusting boundary separation, but not to impaired visuospatial processing specifically. We discuss the implications of these findings for future cognitive research in ADHD.
Divergence point analyses of visual world data: applications to bilingual research
Authors: Stone Kate , Lago Sol , Schad Daniel J.
Published: December 2020

Much work has shown that differences in the timecourse of language processing are central to comparing native (L1) and non-native (L2) speakers. However, estimating the onset of experimental effects in timecourse data presents several statistical problems including multiple comparisons and autocorrelation. We compare several approaches to tackling these problems and illustrate them using an L1-L2 visual world eye-tracking dataset. We then present a bootstrapping procedure that allows not only estimation of an effect onset, but also of a temporal confidence interval around this divergence point. We describe how divergence points can be used to demonstrate timecourse differences between speaker groups or between experimental manipulations, two important issues in evaluating L2 processing accounts. We discuss possible extensions of the bootstrapping procedure, including determining divergence points for individual speakers and correlating them with individual factors like L2 exposure and proficiency. Data and an analysis tutorial are available athttps://osf.io/exbmk/.
Delivery of the National Child Measurement Programme in England
Authors: Čadek Martin , Flint Stuart W , Tench Ralph
Published: December 2020

Objective:

The National Child Measurement Programme (NCMP) is a mandatory initiative delivered in England to children in Reception and Year 6. To date, no research has explored the methods used to deliver the NCMP by Local Government Authorities (LGA) across England.

Design:

An online survey was administered between February 2018 and May 2018 to explore the delivery of the NCMP across the 152 LGA in England and disseminated using non-probability convenience sampling.

Setting:

LGA received an anonymous link to the survey.

Participants:

A total of 92 LGA participated in the survey.

Results:

Most LGA who responded provide result feedback (86 %), a proactive follow-up (71 %) and referrals to services (80 %). Additionally, 65 % of the authorities tailor Public Health England specimen result letters to suit their needs, and 84 % provide attachments alongside. Out of 71 % of LGA who provide proactive follow-up, 19 (29 %) provide the proactive follow-up only to upper weight categories and only 4 (6 %) include Healthy Weight category with other categories in proactive follow-up. Regarding the service availability for children, out of 80 % of LGA who indicated that services are available, 32 (43 %) targeted solely upper weight categories, while the other 42 (57 %) offered services across all weight categories. Finally, most LGA (88 %) commission providers to manage various parts of the NCMP.

Conclusions:

The results show that LGA in England localise the NCMP. Further guidance regarding standards of best practice would help LGA to find the most suitable localisation out of various options that exist across other LGA.
D-Minor Concertos and Symphonies of the Brahms–Schumann Circle in the 1850s: Cross-Relationships and the Influence of Beethoven
Authors: Sholes Jacquelyn
Published: December 2020

This article examines cross-relationships and mutual influences in the D-minor symphonies and concertos written in the 1850s by a close-knit circle of composers: Johannes Brahms, Robert Schumann, and their friends Joseph Joachim, Julius Otto Grimm and Albert Dietrich. Outlining the overlapping compositional timelines of Brahms's First Piano Concerto (at one point a candidate to become his first symphonic work), the violin concertos of Joachim and Schumann, and the symphonies of Grimm and Dietrich, it demonstrates that the pieces were shared among the composers during their periods of composition and explores musical correspondences indicating mutual influences both among the composers and from other specific works. The musical choices involved in this group of pieces seem to point to an underlying backdrop of Beethovenian influence involving specific works from Beethoven's body of orchestral music, an oeuvre concluding with an unforgettable symphonic work in D minor—to which the younger generation's collection of works may relate symbolically. This study not only emphasizes the central role that Beethoven played in the minds of these composers in the mid-1850s, but also underscores the musical intimacy that extended from the social intimacy of the composers in the Brahms–Schumann circle.
On money as a conventional sign: revisiting Aristotle's conception of money
Authors: Crespo Ricardo F.
Published: December 2020

Regardless of the historical evolution of money, some passages of Aristotle's works shed light on its meaning and nature. This paper will attentively consider these passages. The first section presents Aristotle's thoughts on money. While the second section analyses money as a unit of measurement, the third section deals with its conventional nature, and the fourth draws from the theories of signs elaborated by John Poinsot and Charles Peirce to expand the explanation of the nature of money as a sign. The conclusion considers three levels of consideration of money based on Aristotle's thoughts: (1) universal abstract money, (2) instantiated in specific currencies, and (3) the actualization of their properties and potentialities in actual economic dealings.
Teaching Translation Theory and Practice
Authors: Praet Stijn , Verhelst Berenice
Published: December 2020

It is safe to say that, across the globe, translation is still heavily relied on as a tool for teaching classical languages and texts that are written in them, both in secondary and higher education. Indeed, translation exercises are perhaps the most common method to train and evaluate Greek and Latin text comprehension, grammar, syntax and vocabulary. Some teachers and textbooks also make use of existing translations to complement and supplement the (more or less) original texts that they are tackling in class. Given that translation plays such a prominent role in Classics, is it not remarkable, then, that students generally spend very little time reflecting on the act of translation itself, not just as a shift between different languages, but as a transfer and transformation of meaning and form between different cultures?
A case study investigation of student perceptions of women as seen in theCambridge Latin Coursein a selective girls grammar school
Authors: Amos Emily
Published: December 2020

‘In 1986 we should no longer settle for books that present women as almost invisible entities.’

(Charlayne Allan, 1986, p.6).

Charlayne Allan's conclusion in her 1986 work, ‘Images of Women’ calls for a transformation in the inclusion and presentation of women in Classics educational materials. However, 33 years later, the presentation of women in educational textbooks remains a prevalent issue in many countries today with slow progress being made (BBC, 2017). The discipline of Classics has been criticised for being particularly slow in addressing the issue of gender bias in textbooks, both ensuring that there is a female voice in educational materials and also responding to female scholarship (Churchill, 2006, p.86). There has been some criticism of the popular and widely-usedCambridge Latin Coursewith the suggestion that ancient women are not equally or fairly represented through the characters and storylines used in the textbooks (Churchill, 2006; Upchurch, 2013). The course was first written in the 1970s and so, perhaps understandably, lacks strong female characters which might suit the engagement of students of the modern world. One solution which has been proposed by the critics mentioned above is the re-designing of the course with a more equal gender balance. However, I am unsure as to whether this is the best way forward. The re-designing of an entire textbook course (and all its online resources, etc.) is a complex undertaking, especially as theCLChas been carefully constructed around a continuous storyline. The creation of female characters, who would have arealsignificance to students’ learning and understanding of the Roman world, cannot simply be added into the stories without significantly changing the course (Joffe, 2019). Moreover, the way in which women are depicted in theCLCshould not merely be a numerical matter. Consideration of how best to accurately present and teach students about the experiences of women in the Roman world, bearing in mind the Roman patriarchal way of thinking, could be endangered to achieve a mathematical solution for gender balance. The success of theCLCis largely down to its popular storylines and characters and so, for the purposes of my research, I will focus on the balance between the importance of an engaging storyline and at the same time, ensuring that the lives of ancient women are accurately presented through the female characters.
A critical investigation of Y7 students’ perceptions of Roman slavery as evidenced in the stories of theCambridge Latin Course
Authors: Parodi Ella
Published: December 2020

In an article,‘The Slaves were Happy’: High School Latin and the Horrors of Classical Studies,Erik Robinson, a Latin teacher from a public high school in Texas, criticises how, in his experience, Classics teaching tends to avoid in-depth discussions on issues such as the brutality of war, the treatment of women and the experience of slaves (Robinson, 2017). However, texts such as the article ‘Teaching Sensitive Topics in the Secondary Classics Classroom’ (Hunt, 2016), and the book ‘From abortion to pederasty: addressing difficult topics in the Classics classroom’ (Sorkin Rabinowitz & McHardy, 2014) strongly advocate for teachers to address these difficult and sensitive topics. They argue that the historical distance between us and Greco-Roman culture and history can allow students to engage and participate in discussions that may otherwise be difficult and can provide a valuable opportunity to address uncomfortable topics in the classroom. Thus, Robinson's assertion that Classics teaching avoids these sensitive topics may not be so definitive. Regardless, Robinson claims that honest confrontations in the classroom with the ‘legacy of horror and abuse’ from the ancient world can be significantly complicated by many introductory textbooks used in Latin classes, such as theCambridge Latin Course(CLC), one of the most widely used high school Latin textbooks in use in both America and the United Kingdom (Robinson, 2017). In particular, Robinson views the presentation of slavery within theCLCas ‘rather jocular and trivialising’ which can then hinder a reader's perspective on the realities of the violent and abusive nature of the Roman slave trade (Robinson, 2017). As far as he was concerned, the problem lay with the characterisation of theCLC's slave characters Grumio and Clemens, who, he argued, were presented there as happy beings and seemingly unfazed by their positions as slaves. There was never any hint in the book that Grumio or Clemens were unhappy with their lives or their positions as slaves, even though, as theCLCitself states in its English background section on Roman slavery, Roman law ‘did not regard slaves as human beings, but as things that could be bought or sold, treated well or badly, according to the whim of their master’ (CLCI, 1998, p. 78). One might argue, therefore, that there seems to be a disconnect between the English language information we learn about the brutality of the Roman slave trade provided in the background section of Stage 6, and what we can infer about Roman slavery from the Latin language stories involving our two ‘happy’ slaves.
Multispecies sustainability
Authors: Rupprecht Christoph D. D. , Vervoort Joost , Berthelsen Chris , Mangnus Astrid , Osborne Natalie , Thompson Kyle , Urushima Andrea Y. F. , Kóvskaya Maya , Spiegelberg Maximilian , Cristiano Silvio , Springett Jay , Marschütz Benedikt , Flies Emily J. , McGreevy Steven R. , Droz Laÿna , Breed Martin F. , Gan Jingchao , Shinkai Rika , Kawai Ayako
Published: December 2020

Non-technical summary

The sustainability concept seeks to balance how present and future generations of humans meet their needs. But because nature is viewed only as a resource, sustainability fails to recognize that humans and other living beings depend on each other for their well-being. We therefore argue that true sustainability can only be achieved if the interdependent needs of all species of current and future generations are met, and propose calling this ‘multispecies sustainability’. We explore the concept through visualizations and scenarios, then consider how it might be applied through case studies involving bees and healthy green spaces.
Emergence pattern of Palmer amaranth (Amaranthus palmeri) influenced by tillage timings and residual herbicides
Authors: Chahal Parminder S. , Barnes Ethann R. , Jhala Amit J.
Published: December 2020

The evolution of multiple herbicide-resistant weeds, including Palmer amaranth, has necessitated the implementation of an integrated weed management (IWM) program. Understanding weed emergence patterns is critical for developing effective IWM strategies. The objective of this study was to evaluate the effect of tillage timings and residual herbicides on cumulative emergence and emergence pattern of Palmer amaranth. Field experiments were conducted in 2015 and 2016 in a field naturally infested with photosystem (PS) II and 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor-resistant Palmer amaranth near Shickley, Nebraska, in a bare ground study, with no crop planted in the plots, although residues from the preceding corn crop were present on the soil surface. Treatments consisted of shallow tillage timings (early, mid, and late), three premix corn or soybean residual herbicides, and a nontreated control. The Weibull function was fitted to cumulative Palmer amaranth emergence with day of year (DOY) and thermal time (TT) as independent variables. Year by treatment interaction was significant for time to 10%, 25%, 50%, 75%, and 90% Palmer amaranth emergence and cumulative emergence. The majority of Palmer amaranth seedlings emerged early, following early tillage with 90% cumulative emergence occurring on DOY 172 compared with DOY 210 to 212 for mid- and late-tillage, and DOY 194 for the nontreated control in 2015. In 2016, 90% of cumulative emergence following early-, mid-, and late-tillage (DOYs 201 to 211) were similar, and that of the nontreated control (DOY 188) was similar to that of early tillage. Nontreated control and PRE herbicide treatments had similar DOY values for 90% emergence in both years. The number of emerged Palmer amaranth seedlings over the season was higher with shallow tillage than no tillage or with the use of PRE herbicides.
Divergence Measures and Detection Performance for Dispersive Targets in SAR
Authors: Gilman Mikhail , Tsynkov Semyon
Published: December 2020

When electromagnetic waves impinge on objects with complex geometries and/or internal structure, we can observe scattering that is distributed in time rather than instantaneous. To detect and characterize such targets, we build the coordinate‐delay synthetic aperture radar (cdSAR) images by adding a delay term to the standard SAR matched filter. In order to apply this approach to the case of extended targets where the image intensity and phase are subject to strong and rapid variations (the phenomenon called speckle), we sample the cdSAR image at several coordinate‐delay “points” in the vicinity of the scatterer location. The discrimination between the instantaneous and delayed targets is realized through autocorrelation analysis of this sample. Because of the statistical properties of speckle, misclassification errors are inevitable. Hence, prediction of the error rate as a function of system and target parameters becomes an important problem. While Monte Carlo simulations can generate the ensembles of data for direct calculation of the error rate, this approach is computationally demanding because of its slow convergence. In order to simplify the prediction of the error rate, we employ statistical divergence measures, namely, the Hellinger distance and Kullback‐Leibler divergence. These divergence measures are calculated directly from the theoretical models of reflectivity of extended targets that we want to distinguish. We empirically establish a linear relation between the misclassification rate and the Hellinger distance for a certain class of simple target models. This relation allows us to make predictions of the error rate without performing the Monte Carlo simulations.
The Effect of Streamflow, Ambient Groundwater, and Sediment Anisotropy on Hyporheic Zone Characteristics in Alternate Bars
Authors: Monofy A. , Boano F.
Published: December 2020

The hyporheic exchange is the main driver for the biogeochemical transformations of nutrients within a river bed. The current study addresses the variations in hyporheic zone (HZ) characteristics in alternate bars due to different streamflow, ambient groundwater, and sediment anisotropy. Several simulations, using a sequentially coupled surface water‐groundwater model of a synthetic reach with fully developed alternate bars morphology, were performed. Two HZs exist within the streambed; a shallow zone that is more linked to surface water, and a deep one that is more influenced by the groundwater variations. Increasing streamflow, and therefore bar submergence, decreases the hyporheic flow. The residence times distribution is bimodal, which implies the existence of two HZs . This bimodality is enhanced by anisotropic sediment conditions, while it is much milder in isotropic ones. The shallow zone residence times increase when streamflow value rises, while the residence times in the deep HZ are less affected. The mean and median residence times decrease by increasing streamflow in partially submerged case, and they are larger in fully submerged case. The hyporheic flow, area, residence times, and extent decrease by increasing groundwater fluxes. The deep zone is the most affected by the groundwater fluxes. Hyporheic flow and extent values are significantly larger in isotropic conditions than in anisotropic ones. The change in residence times values is different between the deep and shallow zones. A predictive model is driven to predict the hyporheic flux, residence times, and hyporheic depths dependence on bar submergence, ambient groundwater, and sediment anisotropy.
Spatial and Temporal Variability of Diffusive CO2 and CH4 Fluxes From the Amazonian Reservoir Petit‐Saut (French Guiana) Reveals the Importance of Allochthonous Inputs for Long‐Term C Emissions
Authors: Colas Fanny , Chanudet Vincent , Daufresne Martin , Buchet Lucie , Vigouroux Régis , Bonnet Angélique , Jacob Frederick , Baudoin Jean‐Marc
Published: December 2020

Variability in greenhouse gas emissions from reservoirs creates uncertainty in global estimates of C emissions from reservoirs. This study examines the temporal and spatial variability in CO2 and CH4 surface water concentrations and diffusive fluxes from an Amazonian reservoir using an original data set combining both a high temporal (1 central site × 22 years) and spatial (44 sites × 1 season) resolution monitoring. The gas concentrations at the central site decreased over time and suggested reduced bioavailability of C in the initial flooded soil but exhibited strong seasonal variation. Not accounting for this variability may result in uncertainties in estimates of annual concentrations (ranging from −68.9% to +260% for CH4 and from −71.5% to +156% for CO2) and thus in estimates of diffusive gas emissions. Gas concentrations and diffusive fluxes exhibited high spatial variability in the reservoir, 24 years after impoundment. In particular, diffusive fluxes were higher in littoral and transitional areas than in open areas, suggesting a large contribution of allochthonous C to current gaseous emissions. Not accounting for this spatial variability in diffusive fluxes may underestimate the total emissions expressed in CO2 equivalents from the whole reservoir by 50.7%. Our study stresses the importance of well‐resolved temporal and spatial monitoring to provide reliable estimated of C emissions and a comprehensive understanding of the processes involved; both of these inputs are needed to support decision‐making for developing energy strategies.
Modulation of Riverine Concentration‐Discharge Relationships by Changes in the Shape of the Water Transit Time Distribution
Authors: Torres Mark A. , Baronas J. Jotautas
Published: December 2020

The concentrations of weathering‐derived solutes in rivers and their covariance with discharge are thought to reflect reactive‐transport processes in hillslopes and to reveal the sensitivity of solute fluxes to climatic change. It is expected that discharge‐driven changes in water transit times play some role in setting concentration‐discharge (C‐Q) relationships, but knowledge gaps remain. To explore the specific role of changes in the shape of the transit time distribution with discharge, we combine models to simulate C‐Q relationships for major cations and Si as example solutes with contrasting affinities to partition into secondary phases. The model results are compared with an analysis of C‐Q relationships using the Global River Chemistry Database. We find that changes in the shape of the transit time distribution with discharge can produce a range of cation‐Q and Si‐Q relationships that encompasses most of the range observed in real catchments, including positive Si‐Q relationships and variable cation to Si ratios. We find that C‐Q relationships (characterized by power law exponents) can remain approximately constant, even as the Damköhler Number (ratio of transport time scale to reaction time scale) is varied over 3 orders of magnitude. So, in our model analysis, C‐Q relationships are as sensitive to hydrologic variability as they are to reaction rates. Additionally we find that, depending on the storage‐discharge relationship, changes in rainfall patterns can influence C‐Q relationships. Altogether, our results suggest ways in which C‐Q relationships may be nonstationary in response to climatic change and/or vary in space and time due to catchment hydrologic properties.
Define East Asian Monsoon Annual Cycle via a Self‐Organizing Map‐Based Approach
Authors: Dai Lun , Cheng Tat Fan , Lu Mengqian
Published: December 2020

Methods to define the East Asian monsoon usually involve ad hoc and diverse criteria. This study adopts a simple and coherent approach based on the self‐organizing map to systematically derive the monsoon annual cycle based on 850‐hPa wind fields. The derived onset dates in the warm season agree well with the literature despite lacking documentation for winter‐season stages. Linear regression suggests an inverse relationship between the length of the Spring (Meiyu) stage and that of the Pre‐Meiyu (Mid‐summer) stage, suggesting predictability of the Meiyu and Fall onsets. The Aleutian Low, the western North Pacific subtropical high, and the upper‐level westerlies play important roles in the Spring, Pre‐Meiyu, and Meiyu onsets. Observations reveal strong rain belt events form right after the monsoonal wind onsets in the warm season. The proposed approach to deriving monsoon stages and onsets would be useful for monsoon climate studies and operational monsoon diagnosis and forecasting.
Effects of Substorms on High‐Latitude Upper Thermospheric Winds
Authors: Zou Ying , Lyons Larry , Conde Mark , Varney Roger , Angelopoulos Vassilis , Mende Stephen
Published: December 2020

During magnetospheric substorms, high‐latitude ionospheric plasma convection is known to change dramatically. How upper thermospheric winds change, however, has not been well understood, and conflicting conclusions have been reported. Here, we study the effect of substorms on high‐latitude upper thermospheric winds by taking advantage of a chain of scanning Doppler imagers (SDIs), THEMIS all‐sky imagers (ASIs), and the Poker Flat incoherent scatter radar (PFISR). SDIs provide mosaics of wind dynamics in response to substorms in two dimensions in space and as a function of time, while ASIs and PFISR concurrently monitor auroral emissions and ionospheric parameters. During the substorm growth phase, the classical two‐cell global circulation of neutral winds intensifies. After substorm onset, the zonal component of these winds is strongly suppressed in the midnight sector, whereas away from the midnight sector two‐cell circulation of winds is enhanced. Both pre and postonset enhancements are ≥100 m/s above the quiet‐time value, and postonset enhancement occurs over a broader latitude and local‐time area than preonset enhancement. The meridional wind component in the midnight and postmidnight sectors is accelerated southward to subauroral latitudes. Our findings suggest that substorms significantly modify the upper‐thermospheric wind circulation by changing the wind direction and speed and therefore are important for the entire magnetosphere‐ionosphere‐thermosphere system.
Tropospheric Ozone Variability Over Hong Kong Based on Recent 20 years (2000–2019) Ozonesonde Observation
Authors: Liao Zhiheng , Ling Zhenhao , Gao Meng , Sun Jiaren , Zhao Wei , Ma Pengkun , Quan Jiannong , Fan Shaojia
Published: December 2020

The recent 20 years (2000–2019) ozonesonde profiles recorded at the Hong Kong Observatory are analyzed to study the Tropospheric Ozone (TropO3) variability over Hong Kong, South China. The TropO3 profiles are described without the constraints of traditional monthly averages; they are clustered based on a Self‐Organizing Map (SOM) to explore the short‐term variability, and separated into two 10‐year periods to investigate the long‐term variability based on pooled statistical analysis. The roles of precursor emissions, dynamic transport, and photochemical formation in multiple‐timescale TropO3 variability are further evaluated with the aid of meteorological and satellite data, surface observation, emission inventory, and backward trajectory analysis. The results suggest that TropO3 over Hong Kong has a seasonal and vertical distribution featuring a widely recognized spring maximum. The SOM‐based clustering analysis emphasizes a strong dependence of short‐term variability in TropO3 profile patterns on cross‐latitude transport conditions, including rich‐O3 transport from midlatitude region and poor‐O3 transport from tropics. However, high O3 levels throughout the troposphere (usually in early spring) are largely due to the combination of stratospheric intrusion and biomass burning. During the whole study period, the O3 concentrations have increased substantially in the lower troposphere. Springtime wildfire‐related emissions over the upwind Indochina Peninsula are responsible for the lower free‐tropospheric O3 increases. In contrast, the boundary‐layer O3 uptrends with a larger increasing rate near the surface are mostly attributed to the reduced NO titration effect due to the sharp reduction of NOx emissions.
Mobilization of Geochemical Elements to Surface Water in the Active Layer of Permafrost in the Russian Arctic
Authors: Ji Xiaowen , Abakumov Evgeny , Polyakov Vyacheslav , Xie Xianchuan
Published: December 2020

The predicted increase of ground temperatures in the Arctic results in the deepening of the active layer and intensification of geochemical processes. Determining the responses of riparian soil systems to surrounding hydrological flows is important for understanding seasonal changes in hydrological processes. In this study, one soil core from a polygon rim (close to the Taz River, TA) and two soil cores from a riverine terrace (close to the Syoyakha River, SY and Murtyyakha River, MU) in Western Siberia, Russia, and their suprapermafrost water, adjacent surface flows, and river water were sampled for analysis of geochemical elements. Results showed that most elements above their respective detection limits began accumulating in the underlying gleyed layer during September‐October in response to the deepest thaw in the active layer. This study focused on the highly mobile elements in the deepest layer; and found that the transport of organic matter in the upper layer carried these elements to both surface water ponds/flows and suprapermafrost water, and further, to the rivers. The efflux of released elements from surface soil to surrounding surface water appeared to be low. The best linear correlation for both surface flows and river water was with Mn; therefore, Mn may be a proxy for predicting the processes occurring within the active layer during the annual summer‐autumn thaw. Moreover, landscapes with different ice contents may experience changes in the elements transported to surface waters. A general conceptual model for the response of elements to the thawing‐freezing process of the active layer is established.
Tree Rings and Observations Suggest No Stable Cycles in Sierra Nevada Cool‐Season Precipitation
Authors: Williams A. P. , Anchukaitis K. J. , Woodhouse C. A. , Meko D. M. , Cook B. I. , Bolles K. , Cook E. R.
Published: December 2020

California’s water resources rely heavily on cool‐season (November–March) precipitation in the Sierra Nevada. Interannual variability is highly volatile and seasonal forecasting has little to no skill, making water management particularly challenging. Over 1902–2020, Sierra Nevada cool‐season precipitation totals exhibited significant 2.2‐ and 13–15‐year cycles, accounting for approximately 40% of total variability and perhaps signifying potential as seasonal forecasting tools. However, the underlying climate dynamics are not well understood and it is unclear whether these cycles are stable over the long term. We use tree rings to reconstruct Sierra Nevada cool‐season precipitation back to 1400. The reconstruction is skillful, accounting for 55%–74% of observed variability and capturing the 20th‐century 2.2‐ and 13–15‐year cycles. Prior to 1900, the reconstruction indicates no other century‐long periods of significant spectral power in the 2.2‐ or 13–15‐year bands. The reconstruction does indicate significant cyclicity over other extended periods of several decades or longer, however, with dominant periodicities in the ranges of 2.1–2.7 and 3.5–8 years. The late 1700s through 1800s exhibited the highest‐amplitude cycles in the reconstruction, with periodicities of 2.4 and 5.7–7.4 years. The reconstruction should serve to caution against extrapolating the observed 2.2‐ and 13–15‐year cycles to guide future expectations. On the other hand, observations and the reconstruction suggest that interannual variability of Sierra Nevada cool‐season precipitation is not a purely white noise process and research should aim to diagnose the dynamical drivers of extended periods of cyclicity in this critical natural resource.