bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical study on crosswind stability of spherical structures
Authors: Zhou Yu , Ji Xiaowei
Published: July 2021

Karman Vortex Street will be formed when steady incoming flow flows around square cylinder under a certain Reynolds number. The alternate shedding of Karman Vortex Street will affect the structure of the object which will cause structural vibration, and may even cause structural damage in severe cases. The “world’s largest artificial moon” located in Hongguo, Panzhou City, Guizhou Province was selected as the research object in this paper, the flow around characteristics under different crosswind velocity of which are numerically studied by computational fluid dynamics, and then the crosswind stability of the structure is analyzed. Results shows that the vortex shedding mainly occurs in the cylindrical structure, while there is no obvious vortex shedding in the spherical structure and the natural frequency of the artificial moon is much higher than the vortex shedding frequency. There are 3 low-speed regions at different heights on the central section. The lowest velocity appears at the lower part of the leeward side of the spherical structure, and there is even a backflow phenomenon, resultsing in a local vortex. Under the same Reynolds number, Karman vortex street is more likely to appear in cylindrical structure than in spherical structure. In addition, as the Reynolds number increases from 8.1×105 to 1.6×107, except to the increase in overall wind velocity, the characteristics of flow around structure at the rear of the building change little under steady-state condition. The natural frequency of the artificial moon is much higher than the vortex shedding frequency. It means that the crosswind stability of the artificial moon investigated is satisfactory.
ReLU artificial neural networks for the grid adaptation in finite element method
Authors: Fu Xuemei , Chen Luoping , Wu Fanyun
Published: July 2021

In this paper, we study the rectified linear unit (ReLU) artificial neural network (ANN) for grid adaptation in finite element method, which is used for solving differential equations (DEs) with initial/boundary condition. Compared with the classical adaptive finite element method (AFEM), ReLU ANN based on finite element method can keep the number of grid-points constant but change their relative location. Our numerical experiments show that approximate solutions obtained from the classical finite element method by ReLU ANN are more accurate than those obtained by AFEM.
Stabilization of a heat equation with an integral type boundary condition
Authors: Li Xiaoyun , Liu Xinglan , Zhou Zhongcheng
Published: July 2021

This paper considers the stabilization of a heat equation with an integral type nonlocal boundary condition. Via choosing a new intermediate target control system with undetermined term instead of the determined one appeared in the normal backstepping method, we convert the original control system into the intermediate target control system by backstepping transformation. At the same time, we prove the exponential stabilization of the intermediate target control system by Lyapunov function method after choosing an appropriate linear integral feedback control. Then, combined with the invertibility and boundedness of backstepping transformation, we obtain the exponential stability of closed-loop system. Finally, the simulation shows the validity of the main theorem.
Empirical analysis on the export trade patterns in the Chinese antibiotic products
Authors: Hong Yu , Zhang Lin , Li Na , Liu Ting
Published: July 2021

This study used annual data from 1987 to 2019 to analyze the export trade patterns of antibiotic products of China. The weighted indicators of “revealed symmetric comparative advantage for export” (RXcj) is employed to capture the revealed comparative advantage of the Chinese export in the antibiotic products, and the weighted indicators of “export restriction” (HXcj) and “import restriction” (HMcj were used to measure the Chinese export and the import policy interventions. The research data found that the export of antibiotic products is much larger than that of imports, and China has a comparative advantage in the export of antibiotic products. China restricted the export of antibiotic products from 1987 to 1993, and began to promote exports in 1994. However, in 2019, due to the impact of the epidemic, import and export trade policies were limited, relatively speaking, China exported more antibiotic products than its export advantage determined.
Flood characteristic description using the singularity method
Authors: Wang Lei
Published: July 2021

An advanced understanding of the flood mechanism will provide scientific evidence for decision makers for assessing water resources and development planning. Mathematical models can be used to develop new indices for flood characteristics description and forecasting. In this study, a singularity index (fractal model) was developed by using peak flow and flow discharge data with time to describe flooding events in the Oak Ridges Moraine (ORM) area, especially for characterizing flow change properties. It was found that the singularity index can be used to describe flood characteristics, which describes the changing behaviour around the peak of the flood flow. The higher the singularity index, the more quickly the flood process changes, and vice versa. It was also observed that the singularity index is higher when more watersheds have urban land cover, and it is lower when fewer watersheds have urban land cover and more have agricultural land cover.
Prediction of life expectancy in Saudi Arabia by 2030 using ARIMA models
Authors: Alshehri A , El-Halawany F , Abu-Zinadah H
Published: July 2021

Life expectancy at birth (LEB) is a major factor for decision-making bodies when developing new healthcare policies or improving existing ones. This paper, with the help of R language, processes and examine the LEB data in Saudi Arabia from 1960 to 2012 using time-series analysis. To test the validity of the model, LEB data from 2013 to 2018 are used. The performance of the selected auto regressive integrated moving average (ARIMA) model has been calculated using several comparing criteria, commonly used in forecasting statistical evaluation, for fitness and prediction phases. Finally, the Saudi Arabian LEB data from 2018 to 2030 are forecasted and analyzed to correspond with the Saudi Vision 2030 framework.
Inference for additive model at response random missing based on principal component imputation
Authors: Dong Xuchen , Chen Simin
Published: July 2021

In this paper, we consider statistical inference for the additive model when the response is missing at random. The paper proposes a framework for statistical inference under missing data, which integrates basis function approximation and principal component imputed estimation equation (PCIEE). Inverse probability weighting is used to construct robust estimator. Under mild assumptions, the convergence rate of component function estimator is proved. In addition, when the sample size n tends to infinity, the PCIEE-based variable selection can select the real predictor. We also demonstrated the performance of PCIEE through numerical experiments.
A feasible method for training classified data with sparsity
Authors: Zhu Jingsong , Guo Bing , Luo Yingting , Pan Jianxin
Published: July 2021

Family harmony is an important part of social stability and harmony. Facing the rapid growth of divorce disputes, how to hear the cases quickly and fairly is an urgent matter to be solved. Based on judgment documents from courts located in Southwest of China, this paper studies how to evaluate and predict whether or not a case should be divorced. These documents are characterized by their unbalance and sparsity; besides that, most of variables are bearing with missing value. We propose a feasible method that shows high accuracy on both training and testing datasets. Concisely, oversampling and “clustering” are exploited to data pre-preparation, and recursive feature elimination is applied to deal with variables selection. In this paper we combined Random Forest and XGboost to derive a more feasible and precise model that achieves ninety percent of accuracy.
Lattice topological edge and corner modes of photonic crystal slabs
Authors: Zhang Z , You J W , Lan Z , Panoiu N C
Published: July 2021

Surface lattice modes, generated by the evanescent coupling between localized modes of optical resonators arranged in a two-dimensional (2D) array, generally exhibit remarkable optical response beyond the single photonic particle. Here, by employing the lattice mode concept, we demonstrate that lattice topological edge and corner modes can be achieved in properly designed photonic crystal (PhC) slabs. Such slabs consist of an array of finite-sized second-order topological insulators mimicking the 2D Su-Schrieffer-Heeger model. The proposed lattice edge and corner modes emerge within the topological band gap of the PhC slab, which dictates their topological nature. In particular, the band diagram of the lattice corner modes shows that they possess non-degenerate eigenfrequencies and dispersive bands. In addition, we show that the eigenfrequency of the lattice topological modes can be shifted by tuning the intercell and/or intracell optical coupling. Finally, by finely tuning the geometric parameters of the slab, we realize a lattice corner mode possessing flatband dispersion characteristics. Our study can find applications to topological lasing, nonlinearity enhancement, and slow-light effects in topological photonic systems.
Folk Song as Hybrid Art Form
Authors: Atkinson David
Published: July 2021

A number of philosophers of music have proved resistant to the idea that song should be considered as a hybrid art that combines language and music. Separately, Levinson in his influential account of hybrid art forms does not admit folk song, even though he does allow nineteenth-century lieder into the hybrid category. Folk songs are sometimes treated as if they are anterior to and therefore ontologically distinct from the more complex songs of Western art music, or even of modern popular culture. In contrast, this article argues that in a historical perspective English-language folk songs constitute a category of considerable complexity, and that the combination of the two distinct media of language and music is fundamental to any consideration of such songs in an ontological perspective.
Subgroup Analysis of Individuals with Multiple Sclerosis Showing Cognitive Resilience
Authors: Randolph John J , Randolph Jennifer S , Wishart Heather A
Published: July 2021

Objective

Cognitive dysfunction is known to occur in many individuals with multiple sclerosis (MS). However, little is currently known about MS patients without cognitive impairment, including protective factors associated with intact cognition. The present study considered these issues in a sample of MS patients screened for intact subjective and objective cognitive functioning.

Methods

Two MS participant groups from a larger sample were derived: i) participants within 1 standard deviation of controls on measures of objective cognition, subjective cognition, and informant-observed subjective cognition [cognitively resilient MS group (MScr)], and ii) those classified as not cognitively resilient (MSncr). Both groups were compared with age- and gender-matched controls.

Results

Findings indicated that the MScr group was similar to the MSncr group on most disease and demographic variables, and level of fatigue. The MScr group showed higher estimated baseline intellectual ability and reported less anxiety, subclinical depressive symptoms, and pain interference. MScr participants also showed a trend toward more reported compensatory cognitive strategy use than MSncr participants. The MScr group showed comparable reading recognition and pain symptoms to controls.

Conclusions

Our findings provide preliminary information on factors associated with cognitive resilience in MS. Future research should examine resilient individuals with MS to further clarify positive outcomes in this condition.
RAD Adaptive Management for Transforming Ecosystems
Authors: Lynch Abigail J , Thompson Laura M , Morton John M , Beever Erik A , Clifford Michael , Limpinsel Douglas , Magill Robert T , Magness Dawn R , Melvin Tracy A , Newman Robert A , Porath Mark T , Rahel Frank J , Reynolds Joel H , Schuurman Gregor W , Sethi Suresh A , Wilkening Jennifer L
Published: July 2021

Intensifying global change is propelling many ecosystems toward irreversible transformations. Natural resource managers face the complex task of conserving these important resources under unprecedented conditions and expanding uncertainty. As once familiar ecological conditions disappear, traditional management approaches that assume the future will reflect the past are becoming increasingly untenable. In the present article, we place adaptive management within the resist–accept–direct (RAD) framework to assist informed risk taking for transforming ecosystems. This approach empowers managers to use familiar techniques associated with adaptive management in the unfamiliar territory of ecosystem transformation. By providing a common lexicon, it gives decision makers agency to revisit objectives, consider new system trajectories, and discuss RAD strategies in relation to current system state and direction of change. Operationalizing RAD adaptive management requires periodic review and update of management actions and objectives; monitoring, experimentation, and pilot studies; and bet hedging to better identify and tolerate associated risks.
Baseline Functional Connectivity in Resting State Networks Associated with Depression and Remission Status after 16 Weeks of Pharmacotherapy: A CAN-BIND Report
Authors: van der Wijk Gwen , Harris Jacqueline K , Hassel Stefanie , Davis Andrew D , Zamyadi Mojdeh , Arnott Stephen R , Milev Roumen , Lam Raymond W , Frey Benicio N , Hall Geoffrey B , Müller Daniel J , Rotzinger Susan , Kennedy Sidney H , Strother Stephen C , MacQueen Glenda M , Protzner Andrea B
Published: July 2021

Understanding the neural underpinnings of major depressive disorder (MDD) and its treatment could improve treatment outcomes. So far, findings are variable and large sample replications scarce. We aimed to replicate and extend altered functional connectivity associated with MDD and pharmacotherapy outcomes in a large, multisite sample. Resting-state fMRI data were collected from 129 patients and 99 controls through the Canadian Biomarker Integration Network in Depression. Symptoms were assessed with the Montgomery-Åsberg Depression Rating Scale (MADRS). Connectivity was measured as correlations between four seeds (anterior and posterior cingulate cortex, insula and dorsolateral prefrontal cortex) and all other brain voxels. Partial least squares was used to compare connectivity prior to treatment between patients and controls, and between patients reaching remission (MADRS ≤ 10) early (within 8 weeks), late (within 16 weeks), or not at all. We replicated previous findings of altered connectivity in patients. In addition, baseline connectivity of the anterior/posterior cingulate and insula seeds differentiated patients with different treatment outcomes. The stability of these differences was established in the largest single-site subsample. Our replication and extension of altered connectivity highlighted previously reported and new differences between patients and controls, and revealed features that might predict remission prior to pharmacotherapy. Trial registration:ClinicalTrials.gov: NCT01655706.
I Can See Through You: Double Vision in Jennifer Egan’s Look at Me and Alexandra Kleeman’s You Too Can Have a Body Like Mine
Authors: Malone Patricia
Published: July 2021

In this essay, I read Jennifer Egan and Alexandra Kleeman’s work within a distinct strand of contemporary literature, characterized by a turn away from skepticism as regards the transparency of language, a revitalized faith in literary form, and a pronounced interest in the capacity of the novel form as well as a centering of the existential experience of the subject socialized as “woman.” Charting a shift from the paranoid mode of the high postmodernists to the contemporary moment in which appearance – visibility – is a necessary and even desirable form of sociality, I suggest that the turn “from the outside in” is fruitfully understood through consideration of the memoir boom of the 1990s and the “specular moment” of autobiography, reconsidering the dyadic dynamic of the reader–author relationship.
Substance use disorder approaches in US primary care clinics with national reputations as workforce innovators
Authors: O’Malley Denalee M , Abraham Cilgy M , Lee Heather S , Rubinstein Ellen B , Howard Jenna , Hudson Shawna V , Kieber-Emmons Autumn M , Crabtree Benjamin F
Published: July 2021

Background

Over the last decade, primary care clinics in the United States have responded both to national policies encouraging clinics to support substance use disorders (SUD) service expansion and to regulations aiming to curb the opioid epidemic.

Objective

To characterize approaches to SUD service expansion in primary care clinics with national reputations as workforce innovators.

Methods

Comparative case studies were conducted to characterize different approaches among 12 primary care clinics purposively and iteratively recruited from a national registry of workforce innovators. Observational field notes and qualitative interviews from site visits were coded and analysed to identify and characterize clinic attributes.

Results

Codes describing clinic SUD expansion approaches emerged from our analysis. Clinics were characterized as: avoidant (n = 3), contemplative (n = 5) and responsive (n = 4). Avoidant clinics were resistant to planning SUD service expansion; had no or few on-site behavioural health staff; and lacked on-site medication treatment (previously termed medication-assisted therapy) waivered providers. Contemplative clinics were planning or had partially implemented SUD services; members expressed uncertainties about expansion; had co-located behavioural healthcare providers, but no on-site medication treatment waivered and prescribing providers. Responsive clinics had fully implemented SUD; members used non-judgmental language about SUD services; had both co-located SUD behavioural health staff trained in SUD service provision and waivered medication treatment physicians and/or a coordinated referral pathway.

Conclusions

Efforts to support SUD service expansion should tailor implementation supports based on specific clinic training and capacity building needs. Future work should inform the adaption of evidence-based practices that are responsive to resource constraints to optimize SUD treatment access.
Herpes Zoster Vaccines
Authors: Harbecke Ruth , Cohen Jeffrey I , Oxman Michael N
Published: July 2021

Herpes zoster (HZ) affects approximately 1 in 3 persons in their lifetime, and the risk of HZ increases with increasing age. The most common, debilitating complication of HZ is the chronic neuropathic pain of postherpetic neuralgia (PHN). Two herpes zoster vaccines, a live-attenuated varicella-zoster virus (VZV) vaccine (zoster vaccine live [ZVL]; ZOSTAVAX [Merck]) and an adjuvanted VZV glycoprotein E (gE) subunit vaccine (recombinant zoster vaccine [RZV]; SHINGRIX [GlaxoSmithKline]) are licensed for the prevention of HZ and PHN in healthy older adults. The safety and efficacy of both vaccines has been demonstrated in clinical trials in immunocompetent adults and in selected immunocompromised persons and persons with immune-mediated diseases. Numerous real-world effectiveness studies have confirmed the safety and effectiveness of both ZVL and RZV. Recombinant zoster vaccine (RZV) is more effective for prevention of HZ than ZVL. Recombinant zoster vaccine is nonreplicating and is thus safe in immunocompromised persons. Additional zoster vaccines are in different stages of development. Wider distribution of safe and effective zoster vaccines will improve the health and well being of the rapidly growing population of older adults around the world.
Effectiveness of Human Papillomavirus (HPV) Vaccination Against Penile HPV Infection in Men Who Have Sex With Men and Transgender Women
Authors: Winer Rachel L , Lin John , Querec Troy D , Unger Elizabeth R , Stern Joshua E , Rudd Jessica M , Golden Matthew R , Swanson Fred , Markowitz Lauri E , Meites Elissa
Published: July 2021

Background

In the United States, human papillomavirus (HPV) vaccination has been recommended since 2011 for boys aged 11–12 years, with catch-up vaccination recommended through age 26 years for previously unvaccinated men who have sex with men (MSM).

Methods

During 2016–2018, a cross-sectional study enrolled MSM and transgender women aged 18–26 years in Seattle, Washington. Participants submitted self-collected penile swab specimens for HPV genotyping. HPV vaccination history was self-reported. We compared HPV prevalence among vaccinated participants with that in participants with no or unknown vaccination history, using log-binomial regression to estimate adjusted prevalence ratios and confidence intervals.

Results

Among 687 participants, 348 (50.7%) self-reported ever receiving ≥1 HPV vaccine dose; the median age at first HPV vaccination was 21 years, and the median age at first sex, 17 years. Overall, the prevalence of penile quadrivalent HPV vaccine (4vHPV)–type HPV was similar in vaccinated participants (12.1%) and participants with no or unknown vaccination (15.6%) (adjusted prevalence ratio, 0.69 [95% confidence interval, .47–1.01]). However, the prevalence was significantly lower in participants vaccinated at age ≤18 years than in those with no of unknown vaccination (0.15 [.04–.62]), corresponding to a vaccine effectiveness of 85% against 4vHPV-type HPV.

Conclusions

Results suggest that HPV vaccination is effective in preventing penile HPV infections in young MSM when administered at age ≤18 years.
The Value of Tantra: Markets, Modernity, and Mumbai’s Master of Mantra
Authors: Björkman Lisa , Burchett Patton
Published: July 2021

This article examines the vibrant presence of tantric religiosity in contemporary India through a case study of a Mumbai-based tāntrika, whom we call Ramji Pandit, and of the ways in which his Tantra is co-constitutive of contemporary business practices and global market economies. We show how Ramji’s tantric ritual services – based firmly in mantras, yantras, and a “science” of vibrational resonance – trouble the conventional ways that religion and economy are often conceptualized as separate domains of value and practice, thought to act upon one another. At once mediating the contradictions of a market-forward liberal socio-economic order, subverting hegemonic forms of economic rationality, and reinforcing consumerist structures and values of late capitalism, Ramji’s tantric practice is of a piece with today’s global economy in ways that demand further exploration. By investigating the economic and spiritual value projects and goals in which Tantra is enlisted, this article explores the “value of Tantra” today in India and globally.
A discussion of syndromic molecular testing for clinical care
Authors: Cassidy Hayley , Van Genne Mart , Lizarazo-Forero Erley , Gard Lilli , Niesters Hubert G M
Published: July 2021

Current molecular detection methods for single or multiplex pathogens by real-time PCR generally offer great sensitivity and specificity. However, many infectious pathogens often result in very similar clinical presentations, complicating the test-order for physicians who have to narrow down the causative agent prior to in-house PCR testing. As a consequence, the intuitive response is to start empirical therapy to treat a broad spectrum of possible pathogens. Syndromic molecular testing has been increasingly integrated into routine clinical care, either to provide diagnostic, epidemiological or patient management information. These multiplex panels can be used to screen for predefined infectious disease pathogens simultaneously within a 1 h timeframe, creating opportunities for rapid diagnostics. Conversely, syndromic panels have their own challenges and must be adaptable to the evolving demands of the clinical setting. Firstly, questions have been raised regarding the clinical relevance of some of the targets included in the panels and secondly, there is the added expense of integration into the clinical laboratory. Here, we aim to discuss some of the factors that should be considered before performing syndromic testing rather than traditional low-plex in-house PCR.
Neural network-based build time estimation for additive manufacturing: a performance comparison
Authors: Oh Yosep , Sharp Michael , Sprock Timothy , Kwon Soonjo
Published: July 2021

Additive manufacturing (AM) has brought positive opportunities with phenomenal changes to traditional manufacturing. Consistent efforts and novel studies into AM use have resolved critical issues in manufacturing and broadened technical boundaries. Build time estimation is one of the critical issues in AM that still needs attention. Accurate build time estimation is key for feasibility studies, preliminary design, and process/production planning. Recent studies have provided the possibility of neural network (NN)-based build time estimation. In particular, traditional artificial NN (ANN)- and convolutional NN (CNN)-based methods have been demonstrated. However, very little has been done on the performance comparison for build time estimation among the different types of NNs. This study is aimed at filling this gap by designing various NNs for build time estimation and comparing them. Two types of features are prepared as inputs for the NNs by processing three-dimensional (3D) models: (1) representative features (RFs) including dimensions, part volume, and support volume; and (2) the set of voxels generated from designating the cells occupied by the workpiece in a mesh grid. With the combination of NN types and input feature types, we design three NNs: (1) ANN with RFs; (2) ANN with voxels; and (3) CNN with voxels. To obtain large enough label data for reliable training, we consider simulation build time from commercial slicing applications rather than actual build time. The simulation build time is calculated based on a material extrusion process. To address various cases for input models, two design factors (scale and rotation) are considered by controlling the size and build orientation of 3D models. In computational experiments, we reveal that the CNN-based estimation is often more accurate than others. Furthermore, the design factors affect the performance of build time estimation. In particular, the CNN-based estimation is strongly influenced by changing the size of 3D models.
Behavioral flexibility in Wasmannia auropunctata (Hymenoptera: Formicidae)
Authors: Ortiz-Alvarado Yarira , Fernández-Casas Rafael , Ortiz-Alvarado Carlos A , Diaz-Iglesias Emily , Rivera-Marchand Bert
Published: July 2021

Worker division of labor is a defining trait in social insects. Many species are characterized by having behavioral flexibility where workers perform non-typical tasks for their age depending on the colony’s needs. Worker division of labor and behavioral flexibility were examined in the little fire ant Wasmannia auropunctata (Roger, 1863), for which age-related division of labor has been found. Young workers perform nursing duties which include tending of brood and queens, and colony defense, while older workers forage. When nurses were experimentally removed from the colony, foragers were observed carrying out nursing and colony defense duties, yet when foragers were removed nurses did not forage precociously. We also administered juvenile hormone analog, methoprene, to workers. When methoprene was applied, foragers increased their nursing and defense activities while nurses became mainly idle. The behavioral flexibility of foragers of the little fire ant may be evidence of an expansion of worker’s repertoires as they age; older workers can perform tasks they have already done in their life while young individuals are not capable of performing tasks ahead of time. This may be an important adaptation associated with the success of this ant as an invasive species.
Nonmedical Cannabis Use: Patterns and Correlates of Use, Exposure, and Harm, and Cancer Risk
Authors: Cohn Amy M , Blount Benjamin C , Hashibe Mia
Published: July 2021

Cannabis has certain health benefits, but some people may experience harms from use. Co-use of tobacco and cannabis is common. Smoke from cannabis contains many of the same carcinogens and toxicants as the smoke from tobacco, raising concerns that cannabis smoking may be a risk factor for cancer. With growing access to and acceptance of medical and nonmedical cannabis, there is an urgent need to understand the risks and benefits of the current modes of cannabis use and how cannabis may be associated with cancer risk. This monograph summarizes a session from a National Cancer Institute Symposium on nonmedical cannabis use and cancer risk. We had 3 objectives: describe the relation between nonmedical cannabis use and cancer risk, delineate patterns and correlates of cannabis co-use with tobacco, and document potentially harmful inhalational exposure resulting from smoked and vaped cannabis. Methodological limitations in the literature and future research recommendations are provided.
SARS-CoV-2 Incidence and Transmission in 48 K-12 Virginia Public Schools During Community Surge
Authors: Rowland Leah C , Hahn Jennifer B , Jelderks Trudy L , Welch Nancy M , Ramirez Dana W E
Published: July 2021

Among 20 681 students and 4282 staff, the in-school transmission of SARS-CoV-2 appeared low during highest community spread and at 3- to 6-foot distancing. Nine of 820 school cases (1.1%) resulted in spread, with only one student-to-staff transmission. A school epidemiologist and mitigation audit teams were useful.
Safeguarding genome integrity under heat stress in plants
Authors: Han Shin-Hee , Kim Jae Young , Lee June-Hee , Park Chung-Mo
Published: July 2021

Heat stress adversely affects an array of molecular and cellular events in plant cells, such as denaturation of protein and lipid molecules and malformation of cellular membranes and cytoskeleton networks. Genome organization and DNA integrity are also disturbed under heat stress and, accordingly, plants have evolved sophisticated adaptive mechanisms that either protect their genomes from deleterious heat-induced damage or stimulate genome restoration responses. In particular, it is emerging that DNA damage responses are a critical defense process that underlies the acquisition of thermotolerance in plants, during which molecular players constituting the DNA repair machinery are rapidly activated. In recent years, thermotolerance genes that mediate the maintenance of genome integrity or trigger DNA repair responses have been functionally characterized in various plant species. Furthermore, accumulating evidence supports that genome integrity is safeguarded through multiple layers of thermoinduced protection routes in plant cells, including transcriptome adjustment, orchestration of RNA metabolism, protein homeostasis, and chromatin reorganization. In this review, we summarize topical progress and research trends in understanding how plants cope with heat stress to secure genome intactness. We focus on molecular regulatory mechanisms by which plant genomes are secured against the DNA-damaging effects of heat stress and DNA damage is effectively repaired. We also explore the practical interface between heat stress response and securing genome integrity in view of developing biotechnological ways of improving thermotolerance in crop species under global climate change, a worldwide ecological concern in agriculture.
Spectral distortion constraints on photon injection from low-mass decaying particles
Authors: Bolliet Boris , Chluba Jens , Battye Richard
Published: July 2021

Spectral distortions (SDs) of the cosmic microwave background (CMB) provide a powerful tool for studying particle physics. Here we compute the distortion signals from decaying particles that convert directly into photons at different epochs during cosmic history, focusing on injection energies $E_\mathrm{inj}\lesssim 20\, \mathrm{keV}$. We deliver a comprehensive library of SD solutions, using CosmoTherm to compute the SD signals, including effects on the ionization history and opacities of the Universe, and blackbody-induced stimulated decay. Then, we use data from COBE/FIRAS and EDGES to constrain the properties of the decaying particles. We explore scenarios where these provide a dark matter (DM) candidate or constitute only a small fraction of DM. We complement the SD constraints with CMB anisotropy constraints, highlighting new effects from injections at very-low photon energies ($h\nu \lesssim 10^{-4}\, {\rm eV}$). Our model-independent constraints exhibit rich structures in the lifetime-energy domain, covering injection energies Einj ≃ 10−10 eV − 10 keV and lifetimes $\tau _X\simeq 10^5-10^{33}\, \mathrm{s}$. We discuss the constraints on axions and axion-like particles, revising existing SD constraints in the literature. Our limits are competitive with other constraints for axion masses $m_a c^2\gtrsim 27\, {\rm eV}$ and we find that simple estimates based on the overall energetics are generally inaccurate. Future CMB spectrometers could significantly improve the obtained constraints, thus providing an important complementary probe of early-universe particle physics.
Predicting the self-lensing population in optical surveys
Authors: Wiktorowicz Grzegorz , Middleton Matthew , Khan Norman , Ingram Adam , Gandhi Poshak , Dickinson Hugh
Published: July 2021

The vast majority of binaries containing a compact object and a regular star spend most of their time in a quiescent state where no strong interactions occur between components. Detection of these binaries is extremely challenging and only few candidates have been detected through optical spectroscopy. Self-lensing represents a new means of detecting compact objects in binaries, where gravitational lensing of the light from the visible component by the compact object produces periodic optical flares. Here we show that current and planned large-area optical surveys can detect a significant number (∼100–10 000s) of these self-lensing binaries and provide insights into the properties of the compact lenses. We show that many of the predicted population of observable self-lensing binaries will be observed with multiple self-lensing flares; this both improves the chances of detection and also immediately distinguishes them from chance-alignment micro-lensing events. Through self-lensing we can investigate long – but previously hidden – stages of binary evolution and consequently provide new constraints on evolutionary models that impact the number and nature of double compact object mergers.
The reflectance spectra of CV–CK carbonaceous chondrites from the near-infrared to the visible
Authors: Tanbakouei S , Trigo-Rodríguez Josep M , Llorca J , Moyano-Cambero C E , Williams I P , Rivkin Andrew S
Published: July 2021

Carbonaceous chondrite meteorites are so far the only available samples representing carbon-rich asteroids and in order to allow future comparison with samples returned by missions such as Hayabusa 2 and OSIRIS-Rex, it is important to understand their physical properties. Future characterization of asteroid primitive classes, some of them targeted by sample-return missions, requires a better understanding of their mineralogy, the consequences of the exposure to space weathering, and how both affect the reflectance behaviour of these objects. In this paper, the reflectance spectra of two chemically related carbonaceous chondrites groups, precisely the Vigrano (CVs) and Karoonda (CKs), are measured and compared. The available sample suite includes polished sections exhibiting different petrologic types: from 3 (very low degree of thermal metamorphism) to 5 (high degree of thermal metamorphism). We found that the reflective properties and the comparison with the Cg asteroid reflectance class point towards a common chondritic reservoir from which the CV–CK asteroids collisionally evolved. In that scenario, the CV and CK chondrites could be originated from 221 Eos asteroid family, but because of its collisional disruption, both chondrite groups evolved separately, experiencing different stages of thermal metamorphism, annealing, and space weathering.
On the importance of Ca ii photoionization by the hydrogen lyman transitions in solar flare models
Authors: Osborne C M J , Heinzel P , Kašparová J , Fletcher L
Published: July 2021

The forward fitting of solar flare observations with radiation–hydrodynamic simulations is a common technique for learning about energy deposition and atmospheric evolution during these explosive events. A frequent spectral line choice for this process is Ca ii 854.2 nm due to its formation in the chromosphere and substantial variability. It is important to ensure that this line is accurately modelled to obtain the correct interpretation of observations. Here, we investigate the importance of photoionization of Ca ii to Ca iii by the hydrogen Lyman transitions, whilst the Lyman continuum is typically considered in this context in simulations, the associated bound–bound transitions are not. This investigation uses two RADYN flare simulations and reprocesses the radiative transfer using the Lightweaver framework which accounts for the overlapping of all active transitions. The Ca ii 854.2 nm line profiles are found to vary significantly due to photoionization by the Lyman lines, showing notably different shapes and even reversed asymmetries. Finally, we investigate to what extent these effects modify the energy balance of the simulation and the implications on future radiation–hydrodynamic simulations. There is found to be a 10–15 per cent change in detailed optically thick radiative losses from considering these photoionization effects on the calcium lines in the two simulations presented, demonstrating the importance of considering these effects in a self-consistent way.
Damped Lyman-α absorbers from Sloan digital sky survey DR16Q with Gaussian processes
Authors: Ho Ming-Feng , Bird Simeon , Garnett Roman
Published: July 2021

We present a new catalogue of Damped Lyman-α absorbers from SDSS DR16Q, as well as new estimates of their statistical properties. Our estimates are computed with the Gaussian process models presented in Garnett et al., Ho, Bird & Garnett with an improved model for marginalizing uncertainty in the mean optical depth of each quasar. We compute the column density distribution function (CDDF) at 2 < z < 5, the line density (dN/dX), and the neutral hydrogen density (ΩDLA). Our Gaussian process model provides a posterior probability distribution of the number of DLAs per spectrum, thus allowing unbiased probabilistic predictions of the statistics of DLA populations even with the noisiest data. We measure a non-zero column density distribution function for $N_{\rm {HI}}\lt 3 \times 10^{22} \, \rm {cm}^{-2}$ with $95{{\ \rm per\ cent}}$ confidence limits, and $N_{\rm {HI}}\lesssim 10^{22} \, \rm {cm}^{-2}$ for spectra with signal-to-noise ratios >4. Our results for DLA line density and total hydrogen density are consistent with previous measurements. Despite a small bias due to the poorly measured blue edges of the spectra, we demonstrate that our new model can measure the DLA population statistics when the DLA is in the Lyman-β forest region. We verify our results are not sensitive to the signal-to-noise ratios and redshifts of the background quasars although a residual correlation remains for detections from zQSO < 2.5, indicating some residual systematics when applying our models on very short spectra, where the SDSS spectral observing window only covers part of the Lyman-α forest.
Novae heat their food: mass transfer by irradiation
Authors: Ginzburg Sivan , Quataert Eliot
Published: July 2021

A nova eruption irradiates and heats the donor star in a cataclysmic variable to high temperatures Tirr, causing its outer layers to expand and overflow the Roche lobe. We calculate the donor’s heating and expansion both analytically and numerically, under the assumption of spherical symmetry, and find that irradiation drives enhanced mass transfer from the donor at a rate $\dot{m}\propto T_{\rm irr}^{5/3}$, which reaches $\dot{m}\sim 10^{-6}\textrm {~M}_\odot \textrm {~yr}^{-1}$ at the peak of the eruption – about a thousand times faster than during quiescence. As the nova subsides and the white dwarf cools down, $\dot{m}$ drops to lower values. We find that under certain circumstances, the decline halts and the mass transfer persists at a self-sustaining rate of $\dot{m}\sim 10^{-7}\textrm {~M}_\odot \textrm {~yr}^{-1}$ for up to ∼103 yr after the eruption. At this rate, irradiation by the white dwarf’s accretion luminosity is sufficient to drive the mass transfer on its own. The self-sustaining rate is close to the white dwarf’s stable burning limit, such that this bootstrapping mechanism can simultaneously explain two classes of puzzling binary systems: recurrent novae with orbital periods ≈2 h (T Pyxidis and IM Normae) and long-lived supersoft X-ray sources with periods ≈4 h (RX J0537.7–7034 and 1E 0035.4–7230). Whether or not a system reaches the self-sustaining state is sensitive to the donor’s chromosphere structure, as well as to the orbital period change during nova eruptions.
The spatially offset quasar E1821+643: new evidence for gravitational recoil
Authors: Jadhav Yashashree , Robinson Andrew , Almeyda Triana , Curran Rachel , Marconi Alessandro
Published: July 2021

A galaxy merger is expected to cause the formation of a supermassive black hole (SMBH) binary, which itself eventually coalesces through the anisotropic emission of gravitational waves. This may result in the merged SMBH receiving a recoil kick velocity ∼100–1000 kms−1, causing it to oscillate in the gravitational potential of the host galaxy. The luminous quasar E1821+643, identified as an SMBH recoil candidate via spectropolarimetry observations, shows Doppler shifting of the broad emission lines in direct and scattered light, consistent with a relative velocity of 2100 km s−1 between the quasar nucleus and host galaxy. In this paper, we attempt to detect the expected spatial displacement using a combination of optical spectroastrometry and Hubble Space Telescope (HST) narrow-band images. The spectroastrometry reveals a relative spatial displacement between the quasar nucleus and the gas emitting the [O iii] λλ4959, 5007 lines of ∼130 mas (∼580 pc) to the north-west. Our HST images resolve the [O iii] emission on sub-arcsecond scales, showing that it is asymmetrically distributed, extending to radial distances ∼0.5−0.6 arcsec from the nucleus in a wide arc running from the north-east around to the west. A simulated spectroastrometry observation based on the HST [O iii] image indicates that only a small fraction of the measured displacement can be attributed to the asymmetric [O iii] emission. This displacement therefore appears to be a real spatial offset of the quasar nucleus with respect to the narrow-line region, presumed to be located at the host galaxy centre, further supporting the interpretation that a post-merger gravitational recoil of the SMBH has occurred in E1821+643.
The cold circumgalactic medium in emission: Mg ii haloes in TNG50
Authors: Nelson Dylan , Byrohl Chris , Peroux Celine , Rubin Kate H R , Burchett Joseph N
Published: July 2021

We outline theoretical predictions for extended emission from Mg ii, tracing cool ∼104 K gas in the circumgalactic medium (CGM) of star-forming galaxies in the high-resolution TNG50 cosmological magnetohydrodynamical simulation. We synthesize surface brightness maps of this strong rest-frame ultraviolet metal emission doublet (λλ2796, 2803), adopting the assumption that the resonant scattering of Mg ii can be neglected and connecting to recent and upcoming observations with the Keck/KCWI, VLT/MUSE, and BlueMUSE optical integral field unit spectrographs. Studying galaxies with stellar masses 7.5 < log (M⋆/M⊙) < 11 at redshifts z = 0.3, 0.7, 1, and 2 we find that extended Mg ii haloes in emission, similar to their Ly α counterparts, are ubiquitous across the galaxy population. Median surface brightness profiles exceed 10−19 erg s−1 cm−2 arcsec−2 in the central $\sim \,$10 s of kpc, and total halo Mg ii luminosity increases with mass for star-forming galaxies, reaching 1040 erg s−1 for M⋆ ∼ 109.5 M⊙. Mg ii halo sizes increase from a few kpc to ≳ 20 kpc at the highest masses, and sizes are larger for haloes in denser environments. Mg ii haloes are highly structured, clumpy, and asymmetric, with isophotal axial ratio increasing with galaxy mass. Similarly, the amount and distribution of Mg ii emission depends on the star formation activity of the central galaxy. Kinematically, inflowing versus outflowing gas dominates the Mg ii luminosity at high and low galaxy masses, respectively, although the majority of Mg ii halo emission at z ∼ 0.7 traces near-equilibrium fountain flows and gas with non-negligible rotational support, rather than rapidly outflowing galactic winds.
Two Reference-Quality Sea Snake Genomes Reveal Their Divergent Evolution of Adaptive Traits and Venom Systems
Authors: Li An , Wang Junjie , Sun Kuo , Wang Shuocun , Zhao Xin , Wang Tingfang , Xiong Liyan , Xu Weiheng , Qiu Lei , Shang Yan , Liu Runhui , Wang Sheng , Lu Yiming
Published: July 2021

True sea snakes (Hydrophiini) are among the last and most successful clades of vertebrates that show secondary marine adaptation, exhibiting diverse phenotypic traits and lethal venom systems. To better understand their evolution, we generated the first chromosome-level genomes of two representative Hydrophiini snakes, Hydrophis cyanocinctus and H. curtus. Through comparative genomics we identified a great expansion of the underwater olfaction-related V2R gene family, consisting of more than 1,000 copies in both snakes. A series of chromosome rearrangements and genomic structural variations were recognized, including large inversions longer than 30 megabase (Mb) on sex chromosomes which potentially affect key functional genes associated with differentiated phenotypes between the two species. By integrating multiomics we found a significant loss of the major weapon for elapid predation, three-finger toxin genes, which displayed a dosage effect in H. curtus. These genetic changes may imply mechanisms that drove the divergent evolution of adaptive traits including prey preferences between the two closely related snakes. Our reference-quality sea snake genomes also enrich the repositories for addressing important issues on the evolution of marine tetrapods, and provide a resource for discovering marine-derived biological products.
Genome-Wide SNPs Clarify a Complex Radiation and Support Recognition of an Additional Cat Species
Authors: Trindade Fernanda J , Rodrigues Maíra R , Figueiró Henrique V , Li Gang , Murphy William J , Eizirik Eduardo
Published: July 2021

Phylogenetic reconstruction and species delimitation are often challenging in the case of recent evolutionary radiations, especially when postspeciation gene flow is present. Leopardus is a Neotropical cat genus that has a long history of recalcitrant taxonomic problems, along with both ancient and current episodes of interspecies admixture. Here, we employ genome-wide SNP data from all presently recognized Leopardus species, including several individuals from the tigrina complex (representing Leopardus guttulus and two distinct populations of Leopardus tigrinus), to investigate the evolutionary history of this genus. Our results reveal that the tigrina complex is paraphyletic, containing at least three distinct species. While one can be assigned to L. guttulus, the other two remain uncertain regarding their taxonomic assignment. Our findings indicate that the “tigrina” morphology may be plesiomorphic within this group, which has led to a longstanding taxonomic trend of lumping these poorly known felids into a single species.