bluuebunny/crossref_metadata_2025 huggingface dataset:
Asymptotic Analysis of Optimal Vaccination Policies
Authors: Penn Matthew J. , Donnelly Christl A.
Published: January 2023

Targeted vaccination policies can have a significant impact on the number of infections and deaths in an epidemic. However, optimising such policies is complicated, and the resultant solution may be difficult to explain to policy-makers and to the public. The key novelty of this paper is a derivation of the leading-order optimal vaccination policy under multi-group susceptible–infected–recovered dynamics in two different cases. Firstly, it considers the case of a small vulnerable subgroup in a population and shows that (in the asymptotic limit) it is optimal to vaccinate this group first, regardless of the properties of the other groups. Then, it considers the case of a small vaccine supply and transforms the optimal vaccination problem into a simple knapsack problem by linearising the final size equations. Both of these cases are then explored further through numerical examples, which show that these solutions are also directly useful for realistic parameter values. Moreover, the findings of this paper give some general principles for optimal vaccination policies which will help policy-makers and the public to understand the reasoning behind optimal vaccination programs in more generic cases.
A framework for computer vision-based health monitoring of a truss structure subjected to unknown excitations
Authors: Ostrowski Mariusz , Blachowski Bartlomiej , Wójcik Bartosz , Żarski Mateusz , Tauzowski Piotr , Jankowski Łukasz
Published: January 2023

Computer vision (CV) methods for measurement of structural vibration are less expensive, and their application is more straightforward than methods based on sensors that measure physical quantities at particular points of a structure. However, CV methods produce significantly more measurement errors. Thus, computer vision-based structural health monitoring (CVSHM) requires appropriate methods of damage assessment that are robust with respect to highly contaminated measurement data. In this paper a complete CVSHM framework is proposed, and three damage assessment methods are tested. The first is the augmented inverse estimate (AIE), proposed by Peng et al. in 2021. This method is designed to work with highly contaminated measurement data, but it fails with a large noise provided by CV measurement. The second method, as proposed in this paper, is based on the AIE, but it introduces a weighting matrix that enhances the conditioning of the problem. The third method, also proposed in this paper, introduces additional constraints in the optimization process; these constraints ensure that the stiff ness of structural elements can only decrease. Both proposed methods perform better than the original AIE. The latter of the two proposed methods gives the best results, and it is robust with respect to the selected coefficients, as required by the algorithm.
Immunologic Interplay Between HIV/AIDS and COVID-19: Adding Fuel to the Flames?
Authors: Augello Matteo , Bono Valeria , Rovito Roberta , Tincati Camilla , Marchetti Giulia
Published: January 2023

Purpose of Review

HIV/AIDS and COVID-19 have been the major pandemics overwhelming our times. Given the enduring immune disfunction featuring people living with HIV (PLWH) despite combination antiretroviral therapy (cART), concerns for higher incidence and severity of SARS-CoV-2 infection as well as for suboptimal responses to the newly developed vaccines in this population arose early during the pandemics. Herein, we discuss the complex interplay between HIV and SARS-CoV-2, with a special focus on the immune responses to SARS-CoV-2 natural infection and vaccination in PLWH.

Recent Findings

Overall, current literature shows that COVID-19 severity and outcomes may be worse and immune responses to infection or vaccination lower in PLWH with poor CD4 + T-cell counts and/or uncontrolled HIV viremia. Data regarding the risk of post-acute sequelae of SARS-CoV-2 infection (PASC) among PLWH are extremely scarce, yet they seem to suggest a higher incidence of such condition.

Scarce immunovirological control appears to be the major driver of weak immune responses to SARS-CoV-2 infection/vaccination and worse COVID-19 outcomes in PLWH. Therefore, such individuals should be prioritized for vaccination and should receive additional vaccine doses. Furthermore, given the potentially higher risk of developing long-term sequelae, PLWH who experienced COVID-19 should be ensured a more careful and prolonged follow-up.
Neuroticism predicts national vaccination rates across 56 countries
Authors: Vermeulen Nicolas
Published: January 2023

Quite strikingly, there is significant variation in Covid-19 vaccine coverage around the world. Some countries do not progress from around 2-3% while others are close to 100% coverage. In addition to some already known economic, health and sociodemographic predictors, the present research is interested in emotional factors that may predict a significant part of this cross-country variation. We examined the personality factor Neuroticism, which corresponds to the relatively stable tendency to experience negative emotions, anxiety and low tolerance for stress. Results confirm that gross domestic product represents around 50 percent of cross-country variation. Neuroticism added 6 to 9 percent of inter-country variation in vaccination coverage. The results are discussed in relation to the associations between Neuroticism, increased worry, greater attention to Covid-19 related information and confidence, as well as lower vaccine hesitancy.
The beauty and the beast of social media: an interpretative phenomenological analysis of the impact of adolescents' social media experiences on their mental health during the Covid-19 pandemic
Authors: Keles Betul , Grealish Annmarie , Leamy Mary
Published: January 2023

Despite extensive research, the mental health implication of social media in adolescents is not yet understood due to mixed and inconsistent findings and more in-depth qualitative studies are needed to expand our understanding of the impact of social media on adolescent mental health during the Covid-19 pandemic. The purpose of this study was to explore why and how adolescents use social media, adolescents’ lived experiences on social media, how they make sense of these experiences having impact on their mental health, and the influence of the Covid-19 pandemic on their use of social media and mental health. In-depth interviews were conducted with eleven adolescents aged 14–16 (five female, six male) across England. The interviews were audio-recorded, transcribed verbatim and analysed using interpretative phenomenological analysis. Two key themes were identified: the beauty of social media that captured positive experiences and emotions of adolescents and the beast of social media that captured negative experiences and emotions. From the adolescents’ accounts, social media has both positive and negative impacts on their mental health, but mostly positive impacts during the Covid-19 pandemic. The results were discussed in relation to the study aims and previous study findings. Strengths and methodological limitations of the study, implications for future research that emerged from the study were discussed.
Scheduling Closure Periods Is Not an Effective Management Strategy to Reduce Lampenflora in Show Caves
Authors: Piano Elena , Nicolosi Giuseppe , Isaia Marco
Published: January 2023

The conversion of wild caves into tourist sites poses serious threats to the conservation of subterranean environments. Among them, the extensive growth of photosynthetic biofilms induced by artificial lighting—the so-called lampenflora—is of particular concern for cave managers. The identification of cost-effective management actions controlling the growth of lampenflora is therefore required to preserve the environmental and touristic values of show caves. By taking advantage of the closure period imposed to contain the COVID-19 pandemic, we tested whether 6 months of cave closure could be an effective strategy to reduce the concentration of photosynthetic biofilms on speleothems in four geographically close Italian show caves. We compared the concentration of the three main microorganism groups composing lampenflora, i.e., cyanobacteria, diatoms, and green algae, measured in September 2020 with values recorded 6 months after the closure, in May 2021. Although slight variations have been observed across the different sampling sessions, we did not detect any significant effect of the closure period on the overall concentration values of lampenflora. Also, we recorded no significant differences in lampenflora concentration after 4 months of regular tourist use, in September 2021. Our results suggest that management practices based on regulating visits to show caves are not effective strategies to reduce lampenflora. Therefore, management practices aiming at a sustainable use of show caves should focus on the active removal of photosynthetic biofilms.
Marine heatwaves lead to bleaching and mass mortality in a key zoantharian
Authors: Soares Marcelo O. , Rabelo Emanuelle F. , Gurgel Anne L.
Published: January 2023

The increased frequency of severe marine heatwaves (MHWs) is a major contributing factor contributing to mass bleaching and large-scale mortality in reef-building corals. However, the effects of MHWs on other major reef organisms (e.g., zoantharians) are poorly studied. In this study, we demonstrate the vulnerability of the key habitat-forming zoantharian Zoanthus sociatus to severe MHWs. Temporal image analysis from 2019 to 2022 on intertidal South Atlantic reefs shows extensive healthy colonies (2019), bleaching (2020), and mass mortality of Z. sociatus with the occupation of the entire space by filamentous algae (2022). We calculated a loss of 99.6% of total area of the colonies due to mass mortality after the bleaching event. Thermal stress was identified during mass bleaching in Z. sociatus in 2020 by indicators such as MHWs and degree heating weeks (DHWs). In the first 6 months of 2020, this low-latitude region underwent three MHWs at 1.5, 2.0, and 1.3°C above the mean temperature. Moreover, the most intense (2°C) and longest (76 days) MHW occurred near the detected mass bleaching. Furthermore, DHWs (14.5 to 17.6) showed that 2020 had the highest and longest heat stress recorded in this century (since 2001) in this extreme reef. Despite its adaptation to this harsh intertidal habitat, our results showed the vulnerability of Z. sociatus to high heat-light stress on these reefs when exposed to high desiccation, elevated temperatures (>30°C), higher salinities, and solar irradiation at low tides. We suggest that Z. sociatus is most vulnerable to severe and repetitive bleaching due to its higher dependence on autotrophy. In this regard, these marginal reef specialists are near the bleaching threshold limit that increases their vulnerability to environmental changes, such as MHWs, especially in intertidal reefs. Our study highlights the vulnerability of symbiotic zoantharians to heat-light stress and the need to include these organisms in long-term monitoring to assess their recovery potential and resilience to climate change in reefs worldwide.
Multiple skeletons of Rhynchaeites from the London Clay reveal the osteology of early Eocene ibises (Aves, Threskiornithidae)
Authors: Mayr Gerald , Kitchener Andrew C.
Published: January 2023

We describe a new species of Rhynchaeites from the early Eocene London Clay of Walton-on-the-Naze (Essex, UK), which is represented by a partial skeleton comprising a skull and most major postcranial bones. Multiple further partial skeletons are assigned to Rhynchaeites sp. and include skeletal elements that are rarely preserved in Paleogene birds. Rhynchaeites is for the first time included in a phylogenetic analysis, which did not unambiguously resolve its affinities, but provided weak support for a sister group relationship to the Threskiornithidae. If Rhynchaeites is a stem group representative of ibises, its skeletal morphology indicates significant homoplasy in the evolution of Aequornithes, the higher level clade including the Threskiornithidae and most other aquatic or semi-aquatic birds. In particular, Rhynchaeites has much shorter legs than extant ibises and the new fossils show that its palate was schizognathous. Current phylogenies suggest that a desmognathous palate as well as long legs evolved multiple times independently within Aequornithes. Unlike in extant ibises, the tip of the beak of Rhynchaeites lacks a densely pitted surface. We hypothesize that vision played a greater role in the foraging strategy of Rhynchaeites, whereas extant ibises are tactile probers and use their beaks for “remote sensing”.
Satisfaction with acquired transferable competences among university students in Cambodia
Authors: Smekalova Lucie , Chaloupkova Petra , Nemejc Karel , Ny Veit
Published: January 2023

Improving the quality of higher education is one of the priority areas worldwide. Transferable competences acquired during studies play a key role in student employment in the labor market. This study aims to compare, through transversal research, the eight transferable competences required by the labor market across occupational sectors, with the degree of satisfaction with their acquisition by university students in agricultural fields of study in Cambodia. This aim makes it possible, in particular, to identify the educational gap in university preparation for the profession. The data were collected from 439 respondents using a self-evaluation questionnaire. The Kruskal–Wallis test was used to test the significant difference of each transferable competence associated with respondents’ sociodemographic characteristics (gender, field of study, and year of study). The results showed that the highest levels of student satisfaction with sense of responsibility and teamwork and least recognized working with digital technologies and communicating in foreign languages as competences. Additionally, the degree of satisfaction with transferable competences increases among students of later years. This is the first study of transferable competences in Cambodia, allowing a clearer view of education in an Asian environment. Implementing transferable competences in curricula will increase graduates’ employability and strengthen the country’s economic growth.
Fossil Mahogany from the Early Paleogene of India
Authors: Chandra Kajal , Shukla Anumeha , Mehrotra R.C. , Bansal Mahi , Prasad Vandana
Published: January 2023

Meliaceae is an important angiosperm family having floristic and ecological significance in major biomes, especially in tropical rainforests. Well preserved leaflet and pollen comparable to the extant genus Swietenia of the Meliaceae from the late Paleocene-early Eocene sedimentary horizon of the Gurha lignite mine, Rajasthan (western India) are described. The genus Swietenia (usually called mahogany) has scarce and fragmentary fossil records, and its evolutionary and paleobiogeographic history is partly understood. The fossil leaflet is characterized by an asymmetrical microphyll-sized lamina with an entire margin, festooned brochidodromous venation, mainly mixed percurrent tertiary and freely ramified quaternary veins, whereas the fossil pollen grains have a tetra-colporate aperture, relatively short colpi, alolongate pore, and a thick and laevigate exine with pitted to psilate ornamentation. These early Paleogene fossils are the oldest known fossil records of the genus Swietenia and add a new perspective to its paleobiogeographic distribution in Southeast Asia during the early Paleogene and this study would encourage future research endeavors to elucidate the evolution and diversification of the economically important group encompassing the genus Swietenia.
Heat effects on clay-bearing building sandstone
Authors: Franzen Christoph , Krause Dana , Siedel Heiner , Ullrich Bernd
Published: January 2023

Damages due to fire occurred on many monuments and affected building sandstones. Changes in technical properties of heated sandstones are caused by changes in their structure and mineralogy. Therefore, a better knowledge of the changing processes in grain size scale is crucial to understand and assess property changes. The study presents results for the Cotta type Elbe Sandstone, a clay-bearing sandstone that is a widespread material for construction and sculpting. Uniaxial compressive strength and ultrasonic wave velocity as well as changes in colour, structures and mineralogical phases were determined for samples treated at temperatures of 300, 400, 500, 600, 700, 800 and 1250 °C and compared to the untreated material. The results show that minor clay components in the sandstone pores determine the uniaxial compressive strength in dependence of temperature and dry or wet state. Uniaxial compressive strength does not show a decrease even at high temperatures, whereas ultrasonic wave velocity is decreasing continuously with higher temperatures as for many other sandstones. The differing mechanical behaviour of the clay-bearing sandstone can be explained by the phase changes of kaolinite in the pore cement.
Contextualist model evaluation: models in financial economics and index funds
Authors: Vergara-Fernández Melissa , Heilmann Conrad , Szymanowska Marta
Published: January 2023

Philosophers of science typically focus on the epistemic performance of scientific models when evaluating them. Analysing the effects that models may have on the world has typically been the purview of sociologists of science. We argue that the reactive (or “performative”) effects of models should also figure in model evaluations by philosophers of science. We provide a detailed analysis of how models in financial economics created the impetus for the growing importance of the phenomenon of “passive investing” in financial markets. Considering this case motivates the position that we call contextualism about model evaluation, or model contextualism for short. Model contextualism encompasses standard analyses of the epistemic performance of the model, but also includes their reactive aspects. It entails identifying the epistemic and contextual import of the model, the ways in which a model can engender change in the world (which we call the channels of transmission), and the interactions between the epistemic and reactive import of a model.
Pursuitworthiness in the scheme of futures
Authors: Virmajoki Veli
Published: January 2023

In this paper, I argue that analyzing pursuitworthiness in science requires that we study possible futures of science. The merits of different criteria of pursuitworthiness need to be assessed against scenarios of the future of science. Different criteria recognize and ignore different scenarios. As a consequence, different criteria enable us to manage different future possibilities. While it might be impossible to predict the future of science, there are still many interesting things we can say about the possible futures of science. We can construct scenarios of the future of science on the basis of philosophical accounts of science. I point out that the topic of pursuitworthiness is not the only topic that can be approached by connecting philosophy of science with the construction of scenarios.
Comparison of coupled chemical pretreatment and mechanical refining of spruce sawdust: fiber network properties and initial production of lignin-bonded biocomposites
Authors: Hofbauer Cornelia , Serna-Loaiza Sebastian , Windisch Irmgard , Scolari Luisa , Koyun Ayse Nur , Zelaya-Lainez Luis , Füssl Josef , Grothe Hinrich , Hirn Ulrich , Friedl Anton , Harasek Michael
Published: January 2023

Around 50% of sawn wood remains as a by-product during the processing into timber. A large part of these by-products consists of sawdust, which still contains a lot of intact fibers and would have great potential to be used for biocomposite materials. This study investigates the influence of different pretreatments on spruce sawdust in a two-step process, where chemical pretreatments like liquid hot water (LHW), organosolv (OS), and alkali (NaOH) are coupled with a mechanical pretreatment (refining). The idea is to customize a suitable fibrous material for creating a biocomposite with a natural binder as lignin instead of synthetic binders. The first part of the study focused on comparing the different chemical pretreatments and the influence of the refining time. Each chemical pretreatment resulted in a different partially solubilized lignocellulosic matrix profile, making the matrix’s fibers less or more accessible. In the second step, the material was treated in a refiner to fibrillate the embedded fibers, enhancing the flexibility and bonding properties. Paper sheets were produced to evaluate the mechanical properties of the obtained fibrous materials. Based on the results, the most promising material was selected for further investigation. The second part of the study focused on the initial testing of the produced fibrous materials as composites. First, the fibers produced in the first part were impregnated with lignin, forming composite bars through hot-compression molding. Finally, the tensile strength of the composites was determined. Especially with higher pretreatment temperatures and longer refining times, several promising combinations could be found for the two-step process.
Biomass stemmed activated carbon electrodes toward a significant electric double-layer capacitor
Authors: Singh Abhimanyu , Nath Gaurav , Dhapola Pawan Singh , Kumar Sushant , Sharma Tejas , Soo Yee Hang , Jun H. K. , Singh Pramod K. , Kakroo Sunanda , Farid Aalia , Khan Marium , Savilov Serguei V. , Yahya M. Z. A. , Joshi Bhawana
Published: January 2023

The primary goal of the current study is to improve the specific capacitance of electric double-layer (EDLC) device using biomass (Tribulus Terrestris) derived activated carbon electrodes synthesized by chemical activation method. Furthermore, high surface area carbon electrodes are characterized using X-ray diffraction (XRD), RAMAN spectroscopy, and scanning electron microscopy (SEM) to confirm the morphological structure. Finally, the electrochemical performance of fabricated EDLC proves a good agreement data using Cyclic Voltammetry (CV), Low Impedance Spectroscopy (LIS), and Galvanostatic Charge–Discharge (GCD) analysis showing the high specific capacitance of 115 Fg−1 for the optimized 1:2 activated carbon material.
Pattern formation in Vlasov–Poisson plasmas beyond Landau caused by the continuous spectra of electron and ion hole equilibria
Authors: Schamel Hans
Published: January 2023

This review presents an upgraded wave theory adapted to the high fluctuation level of driven realistic, i.e., non-idealized plasmas. Based on the author’s early publication (H. Schamel, Plasma Phys. 14 (1972) 905) and supported by recent Vlasov–Poisson (VP) simulations, an extended theoretical framework is presented which not only covers the essential features of coherent hole structures, but which also enables to make the necessary corrections to the current wave theory. A linear stability analysis for single harmonic waves that successfully incorporates trapped particle effects (in contrast to previous analyses) shows an unconditional marginal stability independent of the drift between electrons and ions, which irrevocably contradicts Landau’s theory. Moreover, holes of negative energy are of particular interest because they act as attractors in the dynamic system. They are the source for the release of further modes and thus increase the level of intermittent turbulence. In summary, pattern formation in collision-free plasmas is inherently nonlinear, kinetic, and extremely diverse. However, to have a satisfactory, if not yet complete understanding of its processes, a twofold paradigm shift is imperative: one from the conventional linear, discrete wave models to the nonlinear wave models dealing with continuous spectra due to trapping and a second from the BGK to the present method for the correct handling of equilibria.
Multivariate curve resolution for kinetic modeling and scale-up prediction
Authors: Schulz Lisa , Stähle Philipp , Reining Sven , Sawall Mathias , Kockmann Norbert , Röder Thorsten
Published: January 2023

An imine synthesis was investigated in a nearly isothermal oscillating segmented flow microreactor at different temperatures using non-invasive Raman spectroscopy. Multivariate curve resolution provided a calibration-free approach for obtaining kinetic parameters. The two different multivariate curve resolution approaches, soft and hard modeling, were applied and contrasted, leading to similar results. Taking heat and mass balance into account, the proposed kinetic model was applied for a model-based scale-up prediction. Finally, the reaction was performed in a 0.5 L semi-batch reactor, followed by in-line Raman spectroscopy and off-line gas chromatography analysis. The successful scale-up was demonstrated with a good agreement between measured and predicted concentration profiles.

Highlights

• Oscillation segmented flow reactor with inline Raman spectroscopy.

• Multivariate Curve Resolution with hard and soft constraints.

• High quality kinetic model for scale-up predictions.

Graphical abstract
Targeted isolation of antitubercular cycloheptapeptides and an unusual pyrroloindoline-containing new analog, asperpyrroindotide A, using LC–MS/MS-based molecular networking
Authors: Han Yi-Qian , Zhang Qun , Xu Wei-Feng , Hai Yang , Chao Rong , Wang Cui-Fang , Hou Xue-Mei , Wei Mei-Yan , Gu Yu-Cheng , Wang Chang-Yun , Shao Chang-Lun
Published: January 2023

Further insights on the secondary metabolites of a soft coral-derived fungus Aspergillus versicolor under the guidance of MS/MS-based molecular networking led to the isolation of seven known cycloheptapeptides, namely, asperversiamides A–C (1–3) and asperheptatides A–D (4–7) and an unusual pyrroloindoline-containing new cycloheptapeptide, asperpyrroindotide A (8). The structure of 8 was elucidated by comprehensive spectroscopic data analysis, and its absolute configuration was determined by advanced Marfey’s method. The semisynthetic transformation of 1 into 8 was successfully achieved and the reaction conditions were optimized. Additionally, a series of new derivatives (10−19) of asperversiamide A (1) was semi-synthesized and their anti-tubercular activities were evaluated against Mycobacterium tuberculosis H37Ra. The preliminary structure−activity relationships revealed that the serine hydroxy groups and the tryptophan residue are important to the activity.
The methodological incompatibility between an innate grammar and a bottom-up approach
Authors: Xie Wei
Published: January 2023

For Universal Grammar (UG), the identification of substantial universals seems unprincipled, because it is indeterminable, with solely bottom-up assumptions, whether a category advanced in UG is entailed by the notion of innateness, or on that basis, what sufficiently evidences its presence. Unable to constrain the theorization of UG, innateness only seems to be inexplicable, that is, it must be questioned how UG is framed within an innate blueprint. I contend that bottom-up assumptions hardly create an innate universal grammar. A theory resulting from bottom-up assumptions is contingent whereas UG must be a promise that the hypothetical Language Faculty (LF) is epistemologically unique (necessary truth). From bottom up, the identity of a linguistic item always points to multiple possibilities and is ad hoc, as no one has real access to the way that a linguistic item naturally exists in LF. Therefore, unless the principle(s) of how categories are recognised and organised in the LF can be genuinely set out for UG, so that its categorisation inputs all linguistic items methodically and outputs their identities uniquely, the putative substantial inventory of UG is unlikely to be complete and systematic: categories in it are merely opportunistically thrown up on random grounds.
Circular and Networked Bioeconomies for Net-Zero Food Production: There is Nothing Magic About Circles
Authors: Tait Joyce , Raybould Alan , Flight Monica Hoyos , McGoohan Amy
Published: January 2023

Future food production will need to deliver a healthy diet to a growing world population whilst also contributing to policy objectives such as achieving Net Zero emissions and addressing biodiversity loss. This article looks at circular economy solutions to this challenge, comparing McArthur Foundation and other approaches to both the circular material economy (e.g. focusing on steel, plastics, aluminium, and cement) and the circular bioeconomy (operating in sectors that include agriculture, food production and industrial biotechnology). A case study based on salmon farming in Scotland considers the roles of innovation from a range of technology sectors in contributing to these objectives. The concept of circularity, and the closed-loop thinking that it encourages, could attract attention towards less optimal production options just because they can be accommodated within a circular model. A ‘networked bioeconomy’ model, guided by cascading principles and fast-tracked using innovative technologies, may be more powerful than one based on rigid closed-loop circularity, in enabling policy makers and producers to understand how they can best contribute both to the conservation of biodiversity and to mitigating climate change.
A Kastler–Kalau–Walze Type Theorem for the J-Twist $$D_{J}$$ of the Dirac Operator
Authors: Liu Siyao , Wang Yong
Published: January 2023

In this paper, we give a Lichnerowicz type formula for the J-twist $$D_{J}$$

D
J

of the Dirac operator. And we prove a Kastler–Kalau–Walze type theorem for the J-twist $$D_{J}$$

D
J

of the Dirac operator on three-dimensional and four-dimensional almost product Riemannian spin manifold with boundary.
Modulation of sediment load recovery downstream of Three Gorges Dam in the Yangtze River
Authors: Zhu Chunyan , Zhang Yuning , van Maren Dirk Sebastiaan , Xie Weiming , Guo Leicheng , Wang Xianye , He Qing
Published: January 2023

The sediment load in the Yangtze River downstream of the Three Gorges Dam (TGD) has substantially declined in recent decades. The decrease is more profound below the TGD, e.g., a 97% decrease at Yichang, compared with that at the delta apex, 1200 km downstream, e.g., a 75% decrease, implying along-river sediment recovery. Two large river-connected lakes, i.e., Dongting and Poyang Lakes, may play a role in the re-establishment of the river’s morphodynamic equilibrium, but a quantitative data-based understanding of this interaction is not yet available. In this work, we collected a series of field data to quantify the sediment gain and loss in the river-lake system in the middle-lower Yangtze River, and evaluate the lake’s response to the reduction in riverine sediment supply. We find that Dongting Lake and Poyang Lake shifted from net sedimentation to erosion in 2006 and 2000, and back to a sedimentation regime again after 2017 and 2018, respectively. Natural morphodynamic adaptation and sand mining play an important role in the regime changes in the Dongting Lake whereas sand mining dominates the abrupt changes in the Poyang Lake. The Dongting and Poyang Lake contributed maximum by 38% (2015) and 17% (2006) (respectively) to the sediment recovery in the erosion regime, whereas the riverbed erosion dominates the main sediment source. These changes in the relative contribution of sediment sources also indicates a response time of ~ 20 years in the lakes towards a new equilibrium state. It is noteworthy that the lakes’ buffer effects may be overestimated as the supplied sediment from the lakes is rather small compared to the significant dam trapping in the upstream basin and sediment source from downstream degradation. The results imply that river management and restoration should take into account of the river-lake interactions and feedback impact at decadal time scales.
Language Contact and Bilingualism
Authors: Appel Rene , Muysken Pieter C.
Published: January 2023

What happens - sociologically, linguistically, educationally, politically - when more than one language is in regular use in a community? How do speakers handle these languages simultaneously, and what influence does this language contact have on the languages involved?

Although most people in the world use more than one language in everyday life, the approach to the study of language has usually been that monolingualism is the norm. The recent interest in bilingualism and language contact has led to a number of new approaches, based on research in communities in many different parts of the world. This book draws together this diverse research, looking at examples from many different situations, to present the topic in any easily accessible form.

Language contact is looked at from four distinct perspectives. The authors consider bilingual societies; bilingual speakers; language use in the bilingual community; finally language itself (do languages change when in contact with each other? Can they borrow rules of grammar, or just words? How can new languages emerge from language contact?). The result is a clear, concise synthesis offering a much-needed overview of this lively area of language study.
Technical Reports: Methods—The Application of Temperature and Light Intensity as Intermittency Sensors in a Temporary Pond
Authors: Campbell Gavin R. , Hyslop Eric J.
Published: January 2023

As climate change progresses, hydrological regimes of temporary and perennial water bodies are projected to change, affecting biodiversity and ecosystem functioning. Researchers have successfully employed the use of satellite imagery, camera traps and site visits to map these changes in hydrological regimes. Data loggers of conductivity have also been used in mapping hydrological regimes, but the use of data loggers of temperature and light intensity is uncommon. Using validated data of 213 days of the aquatic and terrestrial phases of a temporary pond, we show that metrics of temperature and light intensity can be used to discern hydrological state. The aquatic phase had lower measures of both parameters when compared to the terrestrial phase. This was attributed to the high specific heat of the aquatic environment and the absorption and redirection of light in water. The most powerful metrics in discerning hydrological state were diel temperature range, diel maximum temperature and light intensity standard deviation. Greater distinctive power was obtained through the use of multiple metrics of the parameters. In addition, key events such as flooding and drying were identifiable within metrics of both parameters. High‐resolution temperature and light intensity data are able to aid in understanding the dynamics of hydrological state and can be used to monitor ecosystem functions amid changes in temporary and perennial water bodies.
Simulating Debris Flow and Levee Formation in the 2D Shallow Flow Model D‐Claw: Channelized and Unconfined Flow
Authors: Jones Ryan P. , Rengers Francis K. , Barnhart Katherine R. , George David L. , Staley Dennis M. , Kean Jason W.
Published: January 2023

Debris flow runout poses a hazard to life and infrastructure. The expansion of human population into mountainous areas and onto alluvial fans increases the need to predict and mitigate debris flow runout hazards. Debris flows on unconfined alluvial fans can exhibit spontaneous self‐channelization through levee formation that reduces lateral spreading and extends runout distances compared to unchannelized flows. Here we modify the D‐Claw shallow flow model in two ways that are hypothesized to generate levees. We evaluate these modifications with observations from a large‐scale flume experiment. We investigate model performance when including the effect of two different friction sub‐models, as well as the inclusion of segregation effects on granular permeability. Results show that, for a wide range of plausible model input parameters, simulations including the effects of segregation promoted modeled levee formation, whereas simulations without the effects of segregation did not create levees. Further, using a forward predictive framework, simulations with the effects of segregation were more likely to better model the magnitude of debris flow depth and runout distance, whereas simulation timing of the debris flow was affected by the choice of friction sub‐model. Our results indicate that including the effects of segregation on granular permeability can improve the likelihood of better predictions of debris flow depth and runout prior to an event occurring.
Colder Eastern Equatorial Pacific and Stronger Walker Circulation in the Early 21st Century: Separating the Forced Response to Global Warming From Natural Variability
Authors: Heede Ulla K. , Fedorov Alexey V.
Published: January 2023

Since the early 1990s the Pacific Walker circulation shows a multi‐decadal strengthening, which contradicts future model projections. Whether this trend, evident in many climate indices especially before the 2015 El Niño, reflects the coupled ocean‐atmosphere response to global warming or the negative phase of the Pacific Decadal Oscillation (PDO) remains debated. Here we show that sea surface temperature trends during 1980–2020 are dominated by three signals: a spatially uniform warming trend, a negative PDO pattern, and a Northern Hemisphere‐Indo‐West Pacific warming pattern. The latter pattern, which closely resembles the transient ocean thermostat‐like response to global warming emerging in a subset of CMIP6 models, shows cooling in the central‐eastern equatorial Pacific but warming in the western Pacific and tropical Indian Ocean. Together with the PDO, this pattern drives the Walker circulation strengthening in the equatorial band. Historical simulations appear to underestimate this pattern, contributing to the models' inability to replicate the Walker cell strengthening.
Midwinter Dry Spells Amplify Post‐Fire Snowpack Decline
Authors: Hatchett Benjamin J. , Koshkin Arielle L. , Guirguis Kristen , Rittger Karl , Nolin Anne W. , Heggli Anne , Rhoades Alan M. , East Amy E. , Siirila‐Woodburn Erica R. , Brandt W. Tyler , Gershunov Alexander , Haleakala Kayden
Published: January 2023

Increasing wildfire and declining snowpacks in mountain regions threaten water availability. We combine satellite‐based fire detections with snow seasonality classifications to examine fire activity in California's seasonal and ephemeral snow zones. We find a nearly tenfold increase in fire activity during 2020–2021 versus 2001–2019. Accumulation season broadband snow albedo declined 25%–71% at two burned sites (2021 and 2022) according to in‐situ data relative to un‐burned conditions, with greater declines associated with increased burn severity. By enhancing snowpack susceptibility to melt, both decreased snow albedo and canopy drove midwinter melt during a multi‐week dry spell in 2022. Despite similar meteorological conditions in December–February 2013 and 2022–linked to persistent high pressure weather regimes–minimal melt occurred in 2013. Post‐fire snowpack differences are confirmed with satellite measurements. With growing geographical overlap between wildfire and snow, our findings suggest California's snowpack is increasingly vulnerable to the compounding effects of dry spells and wildfire.
Projected Changes in the Seasonal Cycle of Madden‐Julian Oscillation Precipitation and Wind Amplitude
Authors: Bui Hien X. , Hsu Pang‐Chi
Published: January 2023

Although recent studies have examined the responses of annual‐ and seasonal‐mean Madden‐Julian oscillation (MJO) activity to global warming, little is known about the seasonal cycle changes that determine the timing of the peak MJO influence on local weather and climate. By analyzing the Community Earth System Model version 2 large ensemble at the end of the 21st century, we report changes in both the phase and amplitude of the seasonal cycle of MJO precipitation over the tropical Indian Ocean and southwestern Pacific. While the seasonal delay in phase of the MJO is related to the seasonal delay of total precipitation, with contributions from surface latent heat flux and circulation changes, the amplification in seasonal amplitude is consistent with the increase in MJO amplitude due to mean temperature increases. The shifts in phase of the seasonal cycle of the MJO under global warming may influence the predictability of extreme events.
Magnetosonic Waves Observed by the Van Allen Probe‐A Satellite: The Chirikov Resonance Overlap Criterion
Authors: Wang Yangyang , Ouyang Zhihai , Tang Rongxin , Li Haimeng , Yu Xiongdong , Yuan Zhigang , Deng Xiaohua
Published: January 2023

Magnetosonic waves (MSWs) can be discrete or continuous in a time‐frequency spectrogram. For discrete MSWs that satisfy the Chirikov resonance overlap criterion (CROC), the spectrum can be regarded as continuous and hence the quasi‐linear theory can be employed to calculate the corresponding electron diffusion coefficient; otherwise, the contribution of each harmonic emission to the diffusion coefficient should be calculated separately. From the Van Allen Probe‐A (RBSP‐A) burst mode observations taken between January 2014 to December 2017, a total of 21,766 discrete MSW events were selected for statistical analysis, among which 314 events (1.44%) are found to not satisfy the CROC. The MSW events not satisfying the CROC are mainly distributed in the range between L ∼ 4 and 6 outside the plasmapause, they all have a frequency gap (e.g., a frequency difference ≥2 fcH between two discrete bands).
Resonant Scattering of Radiation Belt Electrons at Saturn by Ion Cyclotron Waves
Authors: Cao Xing , Lu Peng , Ni Binbin , Summers Danny , Shprits Yuri Y. , Long Minyi , Wang Xiaoyu
Published: January 2023

By constructing an empirical model of the spectral and latitudinal distribution of ion cyclotron waves on the basis of Cassini datasets, we investigate the resonant interactions between ion cyclotron waves and radiation belt electrons at Saturn. Calculations based on quasi‐linear bounce‐averaged diffusion coefficients show that at Saturn ion cyclotron waves can efficiently pitch angle scatter >∼1 MeV to tens of MeV electrons into the loss cone thereby inducing precipitation loss, while the mixed and momentum scattering effects are typically negligible. The resultant electron loss timescales range from a few to tens of minutes, which in fact decrease significantly with increasing L‐shell at L = 4–6. We also find that the kinetic effects introduced by pick‐up ring particles cause distinct changes in pitch angle scattering efficiency for lower energy electrons (<3 MeV at L = 5). Our results demonstrate that ion cyclotron waves play a significant role in the dynamics of Saturn's radiation belt electrons.
Factors Controlling the Sea Surface Partial Pressure of Carbon Dioxide in Upwelling Regions: A Case Study of the Southern East China Sea Before and After Typhoon Maria
Authors: Kao Kai‐Jung , Huang Wei‐Jen , Chou Wen‐Chen , Gong Gwo‐Ching , Weerathunga Veran
Published: January 2023

Upwelling regions, which account for 10%–20% of the global ocean's primary production but occupy only 3% of its area, play an important role in the global ocean carbon cycle. However, controlling factors of the partial pressure of carbon dioxide (pCO2) in upwelling regions before and after typhoons remain unclear. Sea surface pCO2 was measured in two upwelling regions of the southern East China Sea (sECS) before (6–9 July 2018) and after (13–17 July 2018) Typhoon “Maria.” Surface pCO2 values were 325.1 ± 18.3 and 322.9 ± 17.4 μatm on the shelf break and middle shelf, respectively, before the typhoon. After the typhoon, the surface pCO2 values dropped to 315.5 ± 15.9 and 305.7 ± 7.2 μatm on the shelf break and middle shelf, respectively. The analysis shows that factors controlling pCO2 variations are the temperature effect (38% to 40%), net biological activities (−33% to −36%), and mixing (−24%), irrespective of whether the measurements were taken before or after the typhoon. During our study period, the upwelling regions in sECS acted as strong sinks of atmospheric CO2 (−4.2 ± 1.2 to −14.1 ± 1.2 mmol m−2 d−1). We suggested that the temperature change, net biological activities, and mixing during the upwelling process characterized the biogeochemical responses over the sECS.
Spatial‐Temporal Variability and Sources of Lead (Pb) in the Indian Ocean and Asian Marginal Seas
Authors: Qian Na , Boyle Edward A. , Zhou Liping , Tanzil Jani , Chen Qinqin , Zhang Shuo , Chen Mengli
Published: January 2023

Since North America and European countries phased out leaded gasoline, Asia has become the major contemporary lead (Pb) source to the marine environment, at first from leaded gasoline, but more recently from coal burning and other high‐temperature industrial activities (Flegal et al., 2013, https://doi.org/10.1080/10643389.2012.671738; Lee et al., 2014, https://doi.org/10.1016/j.epsl.2014.04.030). Pb in the Indian Ocean remains relatively under‐evaluated after ∼2000 and is further complicated by various oceanic processes (e.g., monsoons, boundary exchange with particulates). Here, we present three annually resolved coral skeletal Pb isotope and concentration records from the central and eastern Indian Ocean (Salomon Atoll, 1989–2009; Diego Garcia Atoll, 1999–2009; and Phuket Island, 1945–2010), and synthesize published coral/sedimentary records to reconstruct the spatial‐temporal variability of anthropogenic Pb around the region. Pb isotopes in all corals coherently fall along the mixing line between Asian aerosols and the natural crust. However, higher contributions of natural Pb are found in corals located in the coastal region than those in the open ocean, despite the greater contributions of anthropogenic Pb expected in coastal water near human emission sources. This geographical difference suggests that exchanges between dissolved Pb and natural particles at ocean boundaries significantly contribute to the Pb isotope compositions in regional seawater and are subsequently recorded in corals. The temporal variability of Pb concentrations in corals and sedimentary records signifies decreasing trends in Southeast Asia but increasing trends in South Asia. This study contributes new and timely Pb and Pb isotope data for the Indian Ocean and illustrates the importance of boundary exchange in marine Pb cycling.
Evaluating BC Aging Processes in the Community Atmosphere Model Version 6 (CAM6)
Authors: Shen Wenxiang , Wang Minghuai , Liu Yawen , Dong Xinyi , Zhao Delong , Yue Man , Tian Ping , Ding Deping
Published: January 2023

The uncertainty of the climatic effect of Black carbon (BC) remains large. One critical uncertainty source that needs to be captured is BC aging. Here we use the Community Atmosphere Model version 6 (CAM6) configured with the four‐mode version of the Modal Aerosol Module (MAM4) to evaluate the modeled BC aging process with recent laboratory and in‐situ measurements over China. As revealed by the comparison of BC aging timescale and number fraction of aged BC against recent measurements, the modeled condensation aging timescale is estimated to be about 0.8 hr (17%) faster than the chamber measurement, and the diurnal variations of modeled BC aging degree are typically higher than observations mainly due to the fast increase in modeled BC aging degree during daytime. Further analysis shows that the condensation aging dominates (>70%) BC aging across China. More specifically, the condensation of secondary organic aerosol (SOA) vapor contributes most to BC aging over China. Slowing down BC aging increases the modeled surface BC concentration over remote Western China and BC burden, but hardly changes surface BC concentration over Eastern China. Our results suggest that BC aging representation in the MAM4 needs to be further improved toward slowing down the BC aging rate, especially the condensation aging by SOA, to improve the BC simulation over remote areas and its impact on BC transport in MAM4.