bluuebunny/crossref_metadata_2025 huggingface dataset:
Anharmonic spectral features via trajectory-based quantum dynamics: A perturbative analysis of the interplay between dynamics and sampling
Authors: Plé Thomas , Huppert Simon , Finocchi Fabio , Depondt Philippe , Bonella Sara
Published: September 2021

The performance of different approximate algorithms for computing anharmonic features in vibrational spectra is analyzed and compared on model and more realistic systems that present relevant nuclear quantum effects. The methods considered combine approximate sampling of the quantum thermal distribution with classical time propagation and include Matsubara dynamics, path integral dynamics approaches, linearized initial value representation, and the recently introduced adaptive quantum thermal bath. A perturbative analysis of these different methods enables us to account for the observed numerical performance on prototypes for overtones and combination bands and to draw qualitatively correct trends for the numerical results obtained for Fermi resonances. Our results prove that the unequal performances of these approaches often derive from the method employed to sample initial conditions and not, as usually assumed, from the lack of coherence in the time propagation. Furthermore, as confirmed by the analysis reported in Benson and Althorpe, J. Chem. Phys. 155, 104107 (2021), we demonstrate, both via the perturbative approach and numerically, that path integral dynamics methods fail to reproduce the intensities of these anharmonic features and follow purely classical trends with respect to their temperature behavior. Finally, the remarkably accurate performance of the adaptive quantum thermal bath approach is documented and motivated.
Measurements of natCd(γ, x) reaction cross sections and isomer ratio of 115m,gCd with the bremsstrahlung end-point energies of 50 and 60 MeV *
Authors: Nadeem Muhammad , Rahman Md. Shakilur , Shahid Muhammad , Kim Guinyun , Naik Haladhara , Hien Nguyen Thi
Published: September 2021

The flux-weighted average cross sections of natCd(γ, xn)115g,m,111m,109,107,105,104Cd and natCd(γ, x)113g,112,111g,110mAg reactions were measured at the bremsstrahlung end-point energies of 50 and 60 MeV. The activation and off-line γ-ray spectrometric technique was carried out using the 100 MeV electron linear accelerator at the Pohang Accelerator Laboratory, Korea. The natCd(γ, xn) reaction cross sections as a function of photon energy were theoretically calculated using the TALYS-1.95 and the EMPIRE-3.2 Malta codes. Then, the flux-weighted average cross sections were obtained from the theoretical values of mono-energetic photons. These values were compared with the flux-weighted values from the present study and were found to be in general agreement. The measured experimental reaction cross-sections and integral yields were described for cadmium and silver isotopes in the natCd(γ, xn)115g,m,111m,109,107,105,104Cd and natCd(γ, x)113g,112,111g,110mAg reactions. The isomeric yield ratio (IR) of 115g,mCd in the natCd(γ, xn) reaction was determined for the two bremsstrahlung end-point energies. The measured isomeric yield ratios of 115g,mCd in the natCd(γ, xn) reaction were also compared with the theoretical values of the nuclear model codes and previously published literature data of the 116Cd(γ, n) and 116Cd(n, 2n) reactions. It was found that the IR value increases with increasing projectile energy, which demonstrates the characteristic of excitation energy. However, the higher IR value of 115g,mCd in the 116Cd(n, 2n) reaction compared to that in the 116Cd(γ, n) reaction indicates the role of compound nuclear spin alongside excitation energy.
Microstructure and texture evolution with Sm addition in extruded Mg–Gd–Sm–Zr alloy
Authors: Bao Jian , Li Quanan , Chen Xiaoya , Zhang Qian , Chen Ziyi
Published: September 2021

We prepared as-extruded Mg-10Gd-xSm (x = 1, 3, 5)-0.5Zr alloys by indirect extrusion, and the microstructure, texture and mechanical properties of as-extruded Mg-10Gd-xSm-0.5Zr alloys were investigated. The results indicate that the microstructure, texture and strength of as-extruded Mg-10Gd-xSm-0.5Zr alloys take a great variation with Sm addition. Dynamic recrystallized grain size is decreased with increasing Sm content, and the average grain size rapidly reduced to 1.4 μm in as-extruded Mg-10Gd-5Sm-0.5Zr alloys due to abundant Mg5(Gd, Sm) and Mg41(Gd, Sm)5 precipitates and their pinning effect on grain boundaries. With an increasing Sm content, the texture has a significant variation. The fiber texture with 〈10-10〉 axis of Mg matrix parallel to extrusion direction (ED) in as-extruded Mg-10Gd-1Sm-0.5Zr alloy transformed into an abnormal texture with 〈0001〉 axis of Mg matrix parallel to ED in as-extruded Mg-10Gd-3Sm-0.5Zr alloy. The tensile yield strength and Brinell hardness gradually increase with Sm addition due to soild solution strengthening, refined grain boundaries strength and numerous precipitates strengthening. However, the as-extruded Mg-10Gd-5Sm-0.5Zr alloy exhibits the poor ductility due to stress concentration caused by abundant precipitates.
Household Air Pollution and Blood Pressure, Vascular Damage, and Subclinical Indicators of Cardiovascular Disease in Older Chinese Adults
Authors: Kanagasabai Thirumagal , Xie Wuxiang , Yan Li , Zhao Liancheng , Carter Ellison , Guo Dongshuang , Daskalopoulou Stella S , Chan Queenie , Elliott Paul , Ezzati Majid , Yang Xudong , Xie Gaoqiang , Kelly Frank , Wu Yangfeng , Baumgartner Jill
Published: September 2021

Background

Limited data suggest that household air pollution from cooking and heating with solid fuel (i.e., coal and biomass) stoves may contribute to the development of hypertension and vascular damage.

Methods

Using mixed-effects regression models, we investigated the associations of household air pollution with blood pressure (BP) and vascular function in 753 adults (ages 40–79 years) from 3 diverse provinces in China. We conducted repeated measures of participants’ household fuel use, personal exposure to fine particulate air pollution (PM2.5), BP, brachial–femoral pulse wave velocity (bfPWV), and augmentation index. Ultrasound images of the carotid arteries were obtained to assess intima–media thickness (CIMT) and plaques. Covariate information on sociodemographics, health behaviors, 24-h urinary sodium, and blood lipids was also obtained.

Results

Average estimated yearly personal exposure to PM2.5 was 97.5 µg/m3 (SD: 79.2; range: 3.5–1241), and 65% of participants cooked with solid fuel. In multivariable models, current solid fuel use was associated with higher systolic (2.4 mm Hg, 95% CI: −0.4, 4.9) and diastolic BP (1.4 mm Hg, 95% CI: −0.1, 3.0) and greater total area of plaques (1.7 mm2, 95% CI: −6.5, 9.8) compared with exclusive use of electricity or gas stoves. A 1 − ln(µg/m3) increase in PM2.5 exposure was associated with higher systolic (1.5 mm Hg, 95% CI: 0.2, 2.7) and diastolic BP (1.0 mm Hg, 95% CI: 0.4, 1.7) and with greater CIMT (0.02 mm, 95% CI: 0.00, 0.04) and total area of plaques (4.7 mm2, 95% CI: −2.0, 11.5). We did not find associations with arterial stiffness, except for a lower bfPWV (−1.5 m/s, 95% CI: −3.0, −0.0) among users of solid fuel heaters.

Conclusions

These findings add to limited evidence that household air pollution is associated with higher BP and with greater CIMT and total plaque area.
Exploring the Dynamics of Week-to-Week Blood Pressure in Nursing Home Residents Before Death
Authors: Graham Laura A , Lee Sei J , Steinman Michael A , Peralta Carmen A , Rubinsky Anna D , Jing Bocheng , Fung Kathy Z , Odden Michelle C
Published: September 2021

BACKGROUND

Aging is accompanied by an overall dysregulation of many dynamic physiologic processes including those related to blood pressure (BP). While year-to-year BP variability is associated with cardiovascular events and mortality, no studies have examined this trend with more frequent BP assessments. Our study objective is to take the next step to examine week-to-week BP dynamics—pattern, variability, and complexity—before death.

METHODS

Using a retrospective study design, we assessed BP dynamics in the 6 months before death in long-term nursing home residents between 1 October 2006 and 30 September 2017. Variability was characterized using SD and mean squared error after adjusting for diurnal variations. Complexity (i.e., amount of novel information in a trend) was examined using Shannon’s entropy (bits). Generalized linear models were used to examine factors associated with overall BP variability.

RESULTS

We identified 17,953 nursing home residents (98.0% male, 82.5% White, mean age 80.2 years, and mean BP 125.7/68.6 mm Hg). Despite a slight trend of decreasing systolic week-to-week BP over time (delta = 7.2 mm Hg), week-to-week complexity did not change in the 6 months before death (delta = 0.02 bits). Average weekly BP variability was stable until the last 3–4 weeks of life, at which point variability increased by 30% for both systolic and diastolic BP. Factors associated with BP variability include average weekly systolic/diastolic BP, days in the nursing home, days in the hospital, and changes to antihypertensive medications.

CONCLUSIONS

Week-to-week BP variability increases substantially in the last month of life, but complexity does not change. Changes in care patterns may drive the increase in BP variability as one approaches death.
Multicomponent Measurement of Respirable Quartz, Kaolinite and Coal Dust using Fourier Transform Infrared Spectroscopy (FTIR): A Comparison Between Partial Least Squares and Principal Component Regressions
Authors: Stacey Peter , Clegg Francis , Sammon Christopher
Published: September 2021

Exposure to respirable crystalline silica (RCS) is potentially hazardous to the health of thousands of workers in Great Britain. Both X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy can be used to measure RCS to assess exposures. The current method outlined in the Health and Safety Executive’s (HSE) Methods for the Determination of Hazardous Substances (MDHS) guidance series is ‘MDHS 101 Crystalline silica in respirable airborne dust - Direct-on-filter analyses by infrared spectroscopy or x-ray’. This describes a procedure for the determination of time-weighted average concentrations of RCS either as quartz or cristobalite in airborne dust. FTIR is more commonly employed because it is less expensive, potentially portable and relatively easy to use. However, the FTIR analysis of RCS is affected by spectral interference from silicates. Chemometric techniques, known as Partial Least Squares Regression (PLSR) and Principal Component Regression (PCR), are two computational processes that have the capability to remove spectral interference from FTIR spectra and correlate spectral features with constituent concentrations. These two common chemometric processes were tested on artificial mixtures of quartz and kaolinite in coal dust using the same commercially available software package. Calibration, validation and prediction samples were prepared by collecting aerosols of these dusts onto polyvinylchloride (PVC) filters using a Safety in Mines Personal Dust Sampler (SIMPEDS) respirable cyclone. PCR and PLSR analyses were compared when processing the same spectra. Good correlations between the target values, measured using XRD, were obtained for both the PCR and PLSR models e.g. 0.98–0.99 (quartz), 0.98–0.98 (kaolinite) and 0.96–0.97 (coal). The level of agreement between PCR and PLSR was within the 95% confidence value for each analyte. Slight differences observed between predicted PCR and PLSR values were due to the number of optimal principal components applied to each chemometric process. The presence of kaolinite in these samples caused an 18% overestimation of quartz, for the FTIR, when following MDHS 101 without a chemometric method. Chemometric methods are a useful approach to obtain interference-free results for the measurement of RCS from some workplace environments and to provide a multicomponent analysis to better characterise exposures of workers.
Brassinosteroids regulate petal spur length in Aquilegia by controlling cell elongation
Authors: Conway Stephanie J , Walcher-Chevillet Cristina L , Salome Barbour Kate , Kramer Elena M
Published: September 2021

Background and Aims

Aquilegia produce elongated, three-dimensional petal spurs that fill with nectar to attract pollinators. Previous studies have shown that the diversity of spur length across the Aquilegia genus is a key innovation that is tightly linked with its recent and rapid diversification into new ranges, and that evolution of increased spur lengths is achieved via anisotropic cell elongation. Previous work identified a brassinosteroid response transcription factor as being enriched in the early developing spur cup. Brassinosteroids are known to be important for cell elongation, suggesting that brassinosteroid-mediated response may be an important regulator of spur elongation and potentially a driver of spur length diversity in Aquilegia. In this study, we investigated the role of brassinosteroids in the development of the Aquilegia coerulea petal spur.

Methods

We exogenously applied the biologically active brassinosteroid brassinolide to developing petal spurs to investigate spur growth under high hormone conditions. We used virus-induced gene silencing and gene expression experiments to understand the function of brassinosteroid-related transcription factors in A. coerulea petal spurs.

Key Results

We identified a total of three Aquilegia homologues of the BES1/BZR1 protein family and found that these genes are ubiquitously expressed in all floral tissues during development, yet, consistent with the previous RNAseq study, we found that two of these paralogues are enriched in early developing petals. Exogenously applied brassinosteroid increased petal spur length due to increased anisotropic cell elongation as well as cell division. We found that targeting of the AqBEH genes with virus-induced gene silencing resulted in shortened petals, a phenotype caused in part by a loss of cell anisotropy.

Conclusions

Collectively, our results support a role for brassinosteroids in anisotropic cell expansion in Aquilegia petal spurs and highlight the brassinosteroid pathway as a potential player in the diversification of petal spur length in Aquilegia.
CIndex: compressed indexes for fast retrieval of FASTQ files
Authors: Huo Hongwei , Liu Pengfei , Wang Chenhui , Jiang Hongbo , Vitter Jeffrey Scott
Published: September 2021

Motivation

Ultrahigh-throughput next-generation sequencing instruments continue to generate vast amounts of genomic data. These data are generally stored in FASTQ format. Two important simultaneous goals are space-efficient compressed storage of the genomic data and fast query performance. Toward that end, we introduce compressed indexing to store and retrieve FASTQ files.

Results

We propose a compressed index for FASTQ files called CIndex. CIndex uses the Burrows–Wheeler transform and the wavelet tree, combined with hybrid encoding, succinct data structures and tables REF and Rγ, to achieve minimal space usage and fast retrieval on the compressed FASTQ files. Experiments conducted over real publicly available datasets from various sequencing instruments demonstrate that our proposed index substantially outperforms existing state-of-the-art solutions. For count, locate and extract queries on reads, our method uses 2.7–41.66% points less space and provides a speedup of 70–167.16 times, 1.44–35.57 times and 1.3–55.4 times. For extracting records in FASTQ files, our method uses 2.86–14.88% points less space and provides a speedup of 3.13–20.1 times. CIndex has an additional advantage in that it can be readily adapted to work as a general-purpose text index; experiments show that it performs very well in practice.

Availability and implementation

The software is available on Github: https://github.com/Hongweihuo-Lab/CIndex.

Supplementary information

Supplementary data are available at Bioinformatics online.
Intraoperative radiotherapy for pancreatic cancer: implementation and initial experience
Authors: Bhome R , Karavias D , Armstrong T , Hamady Z , Arshad A , Primrose J , Bateman A , Pearce N , Takhar A
Published: September 2021

This article reports on the first series of patients to receive intraoperative radiotherapy for pancreatic cancer in the UK. The data suggest that this treatment modality is feasible and safe, laying a platform for collaborative multicentre trials to better assess efficacy.
Variation in the rates of emergency surgery amongst emergency admissions to hospital for common acute conditions
Authors: Hutchings Andrew , Moler Zapata Silvia , O’Neill Stephen , Smart Neil , Cromwell David , Hinchliffe Robert , Grieve Richard
Published: September 2021

Background

This paper assesses variation in rates of emergency surgery (ES) amongst emergency admissions to hospital in patients with acute appendicitis, cholelithiasis, diverticular disease, abdominal wall hernia, and intestinal obstruction.

Methods

Records of emergency admissions between 1 April 2010 and 31 December 2019 for the five conditions were extracted from Hospital Episode Statistics for 136 acute National Health Service (NHS) trusts in England. Patients who had ES were identified using Office of Population Censuses and Surveys (OPCS) procedure codes, selected by consensus of a clinical panel. The differences in ES rates according to patient characteristics, and unexplained variations across NHS trusts were estimated by multilevel logistic regression, adjusting for year of emergency admission, age, sex, ethnicity, diagnostic subcategories, index of multiple deprivation, number of co-morbidities, and frailty.

Results

The cohort sizes ranged from 107 325 (hernia) to 268 253 (appendicitis) patients, and the proportion of patients who received ES from 11.0 per cent (diverticular disease) to 92.3 per cent (appendicitis). Older patients were generally less likely to receive ES, with adjusted odds ratios (ORs) of ES for those aged 75–79 versus those aged 45–49 years: 0.34 (appendicitis), 0.49 (cholelithiasis), 0.87 (hernia), and 0.91 (intestinal obstruction). Patients with diverticular disease aged 75–79 were more likely to receive ES than those aged 45–49 (OR 1.40). Variation in ES rates across NHS trusts remained after case mix adjustment and was greatest for cholelithiasis (trust median 18 per cent, 10th to 90th centile 7–35 per cent).

Conclusion

For patients presenting as emergency hospital admissions with common acute conditions, variation in ES rates between NHS trusts remained after adjustment for demographic and clinical characteristics. Age was strongly associated with the likelihood of ES receipt for some procedures.
Fiber intake and health in people with chronic kidney disease
Authors: Su Guobin , Qin Xindong , Yang Changyuan , Sabatino Alice , Kelly Jaimon T , Avesani Carla Maria , Carrero Juan Jesus
Published: September 2021

Emerging evidence suggests that diet, particularly one that is rich in dietary fiber, may prevent the progression of chronic kidney disease (CKD) and its associated complications in people with established CKD. This narrative review summarizes the current evidence and discusses the opportunities for increasing fiber intake in people with CKD to improve health and reduce disease complications. A higher consumption of fiber exerts multiple health benefits, such as increasing stool output, promoting the growth of beneficial microbiota, improving the gut barrier and decreasing inflammation, as well decreasing uremic toxin production. Despite this, the majority of people with CKD consume less than the recommended dietary fiber intake, which may be due in part to the competing dietary potassium concern. Based on existing evidence, we see benefits from adopting a higher intake of fiber-rich food, and recommend cooperation with the dietitian to ensure an adequate diet plan. We also identify knowledge gaps for future research and suggest means to improve patient adherence to a high-fiber diet.
Computational Model for Prediction of Malignant Mesothelioma Diagnosis
Authors: Gupta Surbhi , Gupta Manoj Kumar
Published: September 2021

Mesothelioma is an aggressive lung cancer, harms the linings of the lungs. It is one of the deadliest cancers diagnosed in those exposed to fibrous silicate minerals (asbestos). Millions of people face severe consequences as they are diagnosed at late stages. This study presents a comparison of several machine learning approaches with distinct feature sets and addresses the issue of class imbalance. The dataset used in this study is available publicly on the University of California Irvine (UCI) machine learning repository. This study used the resampling technique, synthetic minority oversampling technique (SMOTE), and adaptive synthetic sampling (ADASYN) to handle the class imbalance. Most of the machine learning strategies performed well with the resampling technique. The best accuracy using the resampling strategy was achieved by artificial neural networks (ANN). The highest accuracy was recorded on the feature set selected by principal component analysis (PCA) is 96%. Overall, ensemble techniques performed well. The proposed stacking-based classifier achieved the highest accuracy (89%) on data balanced using SMOTE and ADASYN.
Single-cell RNA sequencing profiling of mouse endothelial cells in response to pulmonary arterial hypertension
Authors: Rodor Julie , Chen Shiau Haln , Scanlon Jessica P , Monteiro João P , Caudrillier Axelle , Sweta Sweta , Stewart Katherine Ross , Shmakova Alena , Dobie Ross , Henderson Beth E P , Stewart Kevin , Hadoke Patrick W F , Southwood Mark , Moore Stephen D , Upton Paul D , Morrell Nick W , Li Ziwen , Chan Stephen Y , Handen Adam , Lafyatis Robert , de Rooij Laura P M H , Henderson Neil C , Carmeliet Peter , Spiroski Ana Mishel , Brittan Mairi , Baker Andrew H
Published: September 2021

Aims

Endothelial cell (EC) dysfunction drives the initiation and pathogenesis of pulmonary arterial hypertension (PAH). We aimed to characterize EC dynamics in PAH at single-cell resolution.

Methods and results

We carried out single-cell RNA sequencing (scRNA-seq) of lung ECs isolated from an EC lineage-tracing mouse model in Control and SU5416/hypoxia-induced PAH conditions. EC populations corresponding to distinct lung vessel types, including two discrete capillary populations, were identified in both Control and PAH mice. Differential gene expression analysis revealed global PAH-induced EC changes that were confirmed by bulk RNA-seq. This included upregulation of the major histocompatibility complex class II pathway, supporting a role for ECs in the inflammatory response in PAH. We also identified a PAH response specific to the second capillary EC population including upregulation of genes involved in cell death, cell motility, and angiogenesis. Interestingly, four genes with genetic variants associated with PAH were dysregulated in mouse ECs in PAH. To compare relevance across PAH models and species, we performed a detailed analysis of EC heterogeneity and response to PAH in rats and humans through whole-lung PAH scRNA-seq datasets, revealing that 51% of up-regulated mouse genes were also up-regulated in rat or human PAH. We identified promising new candidates to target endothelial dysfunction including CD74, the knockdown of which regulates EC proliferation and barrier integrity in vitro. Finally, with an in silico cell ordering approach, we identified zonation-dependent changes across the arteriovenous axis in mouse PAH and showed upregulation of the Serine/threonine-protein kinase Sgk1 at the junction between the macro- and microvasculature.

Conclusion

This study uncovers PAH-induced EC transcriptomic changes at a high resolution, revealing novel targets for potential therapeutic candidate development.
Ant Communities and Ecosystem Services in Organic Versus Conventional Agriculture in the U.S. Corn Belt
Authors: Helms Jackson A , Smith Jamie , Clark Stephanie , Knupp Kathleen , Haddad Nick M
Published: September 2021

Reducing the use of synthetic fertilizers and pesticides can limit negative impacts of agriculture on insects and is a crucial step towards sustainable agriculture. In the United States, organic agriculture has the potential to reduce greenhouse gas emissions, pollutant runoff, and biodiversity loss in the Midwestern Corn Belt—an area extending over 500,000 km2 devoted to intensive production of corn Zea mays (Linnaeus 1753) (Poales: Poaceae), often in rotation with soy Glycine max (Linnaeus 1753) (Fabales: Fabaceae) or wheat Triticum aestivum (Linnaeus 1753) (Poales: Poaceae). Working in 30-yr-long landscape experiments in this region, we tested for impacts of conventional versus organic agriculture on ant communities (Hymenoptera: Formicidae) and potential ecosystem services they provide. Organic fields supported higher ant diversity and a slightly more species-rich ant assemblage than conventionally managed fields but did not otherwise differ in community composition. Despite similar community composition, organic and conventional fields differed in seasonal patterns of ant foraging activity and potential for natural pest suppression. Conventional plots experienced higher overall ant foraging activity, but with the timing skewed towards late in the growing season such that 75% of ant foraging occurred after crop harvest in a wheat year and was therefore unavailable for pest suppression. Organic fields, in contrast, experienced moderate levels of ant foraging activity throughout the growing season, with most foraging occurring during crop growth. Organic fields thus supported twice as much pest suppression potential as conventional fields. Our results highlight the importance of timing in mediating ecosystem services in croplands and emphasize the value of managing landscapes for multiple services rather than yield alone.
Viscoelastic Love numbers and long-period geophysical effects
Authors: Michel A , Boy J-P
Published: September 2021

Long term deformations strongly depend on the earth model and its rheological parameters, and in particular its viscosity. We give the general theory and the numerical scheme to compute them for any spherically non-rotating isotropic earth model with linear rheology, either elastic or viscoelastic. Although the Laplace transform (LT) is classically used to compute viscoelastic deformation, we choose here instead, to implement the integration with the Fourier transform (FT) in order to take advantage of the fast FT algorithm and avoid some of the LT mathematical difficulties. We describe the methodology to calculate deformations induced by several geophysical signals regardless of whether they are periodic or not, especially by choosing an adapted time sampling for the FT. As examples, we investigate the sensitivity of the displacements due to long period solid Earth tides, glacial isostatic adjustment and present-day ice melting, to anelastic parameters of the mantle. We find that the effects of anelasticity are important for long period deformation and relatively low values of viscosities for both Maxwell and Burgers models. We show that slight modifications in the rheological models could significantly change the amplitude of deformation but also affect the spatial and temporal pattern of the signal to a lesser extent. Especially, we highlight the importance of the mantle anelasticity in the low degrees deformation due to present-day ice melting and encourage its inclusion in future models.
Monte Carlo simulations of coupled body- and Rayleigh-wave multiple scattering in elastic media
Authors: Xu Zongbo , Margerin Ludovic , Mikesell T Dylan
Published: September 2021

Seismic coda waves are commonly used in estimation of subsurface Q values and monitoring subsurface changes. Coda waves mainly consist of multiply scattered body and surface waves. These two types of waves interact with each other in the multiple scattering process, which thus leads to a spatiotemporal evolution of the body and surface wave energies. One cannot characterize the evolution because one has not fully understood the multiple scattering of the two types of waves. Thus one commonly assumes only one type of waves exists or ignores their interaction while studying the coda waves. However, neglecting the interaction leads to an incorrect energy evolution of the two types of waves and consequently biases the Q estimation or interpretation of coda wave changes for monitoring. To better understand the interaction between these waves during multiple scattering and to model the energy evolution correctly, we propose a Monte Carlo algorithm to model the multiple scattering process. We describe the physics of the scattering for the two types of waves and derive scattering properties like cross sections for perturbations in elastic properties (e.g. density, shear modulus and Lamé parameters). Our algorithm incorporates this knowledge and thus physically models the body- and surface wave energy evolution in space and time. The energy partitioning ratios between surface and body waves provided by our algorithm match the theoretical prediction based on equipartition theory. In the equipartition state, our simulation results also match Lambert’s cosine law for body waves on the free surface. We discuss how the Rayleigh-to-body-wave scattering affects the energy partitioning ratios. Our algorithm provides a new tool to study multiple scattering and coda waves in elastic media with a free surface.
Synthetic case study: discrimination of unexploded ordnance (UXO) and non-UXO sources with varying remanent magnetization strength using magnetic data
Authors: Wigh Mark David , Hansen Thomas Mejer , Døssing Arne
Published: September 2021

We investigate if it is theoretically possible to discriminate between unexploded ordnance (UXO) and non-UXO sources by modelling the magnetic dipole moment for ferrous objects of different shapes and sizes. This is carried out by approximating the volumetric demagnetization factors of rectangular prisms, representing shapes similar to a long rod or flat steel plate. By modelling different UXO as prolate spheroids the demagnetization factors can be determined which can be compared with the magnetic response of a prism. The inversion is carried out in a probabilistic framework, where the UXO forward model and the non-UXO forward model are assigned individual prior models in terms of shape, size, orientation and remanent magnetization of the object. 95 independent realizations of the prism prior model are generated to make 95 synthetic anomalies exemplifying non-UXO objects, which are inverted for using the UXO model. It is investigated if an identical magnetic moment can be produced between the two models and how well resolved the magnetic moment is in terms of the measured anomaly. The case study is carried out in two steps where we first have little prior information of expected UXO properties and another where a UXO prior is introduced with expected values of aspect ratio and size of 24 different UXO, that are often encountered in the North Sea. With no prior information of expected UXO, discrimination is at many times implausible, unless elongated rod prism objects are considered, where the magnetic moment often can not be reproduced by a spheroid. Introducing the UXO prior we achieve a much better discrimination rate when using the list of expected UXO properties. By using the UXO prior we can account for a much higher remanent magnetization allowed in the prior, and still achieve high discrimination capabilities in comparison to a case with no UXO prior.
A scoping review of the determinants of foetal alcohol spectrum disorder in South Africa: an intersectional perspective
Authors: De Jong Michelle , George Asha , Jacobs Tanya
Published: September 2021

Foetal alcohol spectrum disorder (FASD) affects babies born to mothers who consume alcohol while pregnant. South Africa has the highest prevalence of FASD in the world. We review the social determinants underpinning FASD in South Africa and add critical insight from an intersectional feminist perspective. We undertook a scoping review, guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews guidelines. Drawing from EBSCOhost and PubMed, 95 articles were screened, with 21 selected for analysis. We used the intersectionality wheel to conceptualize how the social and structural determinants of FASD identified by the literature are interconnected and indicative of broader inequalities shaping the women and children affected. Key intersecting social determinants that facilitate drinking during pregnancy among marginalized populations in South Africa documented in the existing literature include social norms and knowledge around drinking and drinking during pregnancy, alcohol addiction and biological dependence, gender-based violence, inadequate access to contraception and abortion services, trauma and mental health, and moralization and stigma. Most of the studies found were quantitative. From an intersectional perspective, there was limited analysis of how the determinants identified intersect with one another in ways that exacerbate inequalities and how they relate to the broader structural and systemic factors undermining healthy pregnancies. There was also little representation of pregnant women’s own perspectives or discussion about the power dynamics involved. While social determinants are noted in the literature on FASD in South Africa, much more is needed from an intersectionality lens to understand the perspectives of affected women, their social contexts and the nature of the power relations involved. A critical stance towards the victim/active agent dichotomy that often frames women who drink during pregnancy opens up space to understand the nuances needed to support the women involved while also illustrating the contextual barriers to drinking cessation that need to be addressed through holistic approaches.
Post-release survival and prolonged sublethal effects of capture and barotrauma on deep-dwelling rockfishes (genus Sebastes): implications for fish management and conservation
Authors: Wegner Nicholas C , Portner Elan J , Nguyen Drew T , Bellquist Lyall , Nosal Andrew P , Pribyl Alena L , Stierhoff Kevin L , Fischer Paul , Franke Ken , Vetter Russell D , Hastings Philip A , Semmens Brice X , Hyde John R
Published: September 2021

Barotrauma—injury induced by changes in pressure—is a widespread challenge for successfully releasing fishes following capture. We used acoustic telemetry to examine the long-term post-release survival and behaviour of four rockfish species (genus Sebastes) suffering from barotrauma following capture using recreational fishing techniques. We placed particular emphasis on examining Cowcod (Sebastes levis) and Bocaccio (Sebastes paucispinis), two historically overfished species along the United States West Coast that serve as good model species representing different ecological lifestyles. We show that fish survival was species specific and that 40% of observed mortality occurred more than 48 h post release—a typical time period used in many short-term survivorship studies. Cowcod survival was correlated with fish length, sea surface temperature, and dissolved oxygen concentration at the mean depth of capture. Generalized additive mixed models of Cowcod and Bocaccio behaviour showed that surviving individuals were negatively affected by capture and barotrauma for at least 30 d post-release. Our findings demonstrate the need for extended observations to accurately quantify the mortality of fishes suffering from barotrauma and show how such data can be successfully implemented into fisheries management through engagement between managers, scientists, and the fishing community.
Using Visual Grouping to Improve Navigation of Skip Patterns in Mail Surveys: An Experiment
Authors: Powell Rebecca J , Smyth Jolene D
Published: September 2021

Skip patterns, in which certain questions should only be answered by subsets of respondents, are particularly challenging for mail surveys because respondents must navigate them themselves with no assistance from a computer or interviewer. Incorrect navigation of skip patterns can lead to (1) errors of omission, which is when respondents fail to answer follow-up questions they should answer; (2) errors of commission, which is when respondents answer follow-up questions they should skip; or (3) filter item nonresponse, which is when respondents fail to answer the initial filter question. Using experimental data from two general population surveys of Nebraskans, this paper examines three visual design elements—common region, indentation, and subnumbering—aimed at decreasing skip errors in mail surveys. Each design element is intended to create stronger grouping and subgrouping among items within skip patterns, thus clarifying the navigational path and decreasing skip errors. We compare error rates across treatments overall and by respondent age, education, and literacy to assess whether visual cues can provide additional aid to those who might struggle with reading text cues. We find that using separate enclosures or subnumbering of the follow-up questions significantly reduces commission error rates and using indentation significantly increases omission error rates. In addition, none of the tested visual designs were more effective for older, less educated, or lower literacy respondents than for their counterparts.
The Eddington ratio-dependent ‘changing look’ events in NGC 2992
Authors: Guolo Muryel , Ruschel-Dutra Daniel , Grupe Dirk , Peterson Bradley M , Storchi-Bergmann Thaisa , Schimoia Jaderson , Nemmen Rodrigo , Robinson Andrew
Published: September 2021

We present an analysis of historical multiwavelength emission of the `Changing Look' (CL) Active Galactic Nucleu (AGN) in NGC 2992, covering epochs ranging from 1978 to 2021, as well as new X-ray and optical spectra. The galaxy presents multiple Seyfert type transitions from Type 2 to intermediate-type, losing and regaining its Hα broad emission lines (BEL) recurrently. In X-rays, the source shows intrinsic variability with the absorption corrected luminosity varying by a factor of ∼ 40. We rule-out tidal disruption events or variable obscuration as causes of the type transitions, and show that the presence and the flux of th Hα BEL is directly correlated with the 2–10 keV X-ray luminosity (L2−10): the component disappears at L2−10 ≤ 2.6 × 1042 $\rm erg\, cm^{-2}\, s^{-1}$; this luminosity value translates into an Eddington ratio (λEdd) of ∼ 1 per cent. The λEdd in which the BEL transitions occur is the same as the critical value at which a state transition between a radiatively inefficient accretion flow and a thin accretion disk is expected, such similarity suggests that the AGN is operating at the threshold mass accretion rate between the two accretion modes. We find a correlation between the narrow Fe Kα flux and λEdd, and an anticorrelation between full-width at half maximum of Hα BEL and λEdd, in agreement with theoretical predictions. Two possible scenarios for type transitions are compatible with our results: either the dimming of the AGN continuum, which reduces the supply of ionizing photons available to excite the gas in the Broad Line Region (BLR), or the fading of the BLR structure itself occurs as the low accretion rate is not able to sustain the required cloud flow rate in a disc-wind BLR model.
improved Master for the LSS: fast and accurate analysis of the two-point power spectra and correlation functions
Authors: Singh Sukhdeep
Published: September 2021

We review the methodology for measurements of two-point functions of the cosmological observables, both power spectra and correlation functions. For pseudo-Cℓ estimators, we will argue that the window-weighted overdensity field can yield more optimal measurements as the window acts as an inverse noise weight, an effect that becomes more important for surveys with a variable selection function. We then discuss the impact of approximations made in the Master algorithm and suggest improvements, the iMaster algorithm, which uses the theoretical model to give unbiased results for arbitrarily complex windows provided that the model satisfies weak accuracy conditions. The methodology of iMaster algorithm is also generalized to the correlation functions to reconstruct the binned power spectra, for E/B mode separation, or to properly convolve the correlation functions to account for the scale cuts in the Fourier space model. We also show that the errors in the window estimation lead to both additive and multiplicative effects on the overdensity field. Accurate estimation of window power can be required up to scales of ∼2ℓmax or larger. Mis-estimation of the window power leads to biases in the measured power spectra, which scale as ${\delta C_\ell }\sim M^W_{\ell \ell ^{\prime }}\delta W_{\ell ^{\prime }}$, where the $M^W_{\ell \ell ^{\prime }}$ scales as ∼(2ℓ + 1)Cℓ leading to effects that can be important at high ℓ. While the notation in this paper is geared towards photometric galaxy surveys, the discussion is equally applicable to spectroscopic galaxy, intensity mapping, and Cosmic Microwave Background radiation (CMB) surveys.
Spectral properties of near-Earth objects with low-Jovian Tisserand invariant
Authors: Simion N G , Popescu M , Licandro J , Vaduvescu O , de León J , Gherase R M
Published: September 2021

The near-Earth objects with low-Jovian Tisserand invariant (TJ) represent about 9 per cent of the known objects orbiting in the near-Earth space, being subject of numerous planetary encounters and large temperature variations. We aim to make a spectral characterization for a large sample of NEOs with TJ ≤ 3.1. Consequently, we can estimate the fraction of bodies with a cometary origin. We report new spectral observations for 26 low-TJ NEOs. The additional spectra, retrieved from different public data bases, allowed us to perform the analysis over a catalogue of 150 objects. We classified them with respect to Bus-DeMeo taxonomic system. The results are discussed regarding their orbital parameters. The taxonomic distribution of low-TJ NEOs differs from the entire NEOs population. Consequently, TJ ∼ 3 can act as a composition border too. We found that 56.2 per cent of low-TJ NEOs have comet-like spectra and they become abundant (79.7 per cent) for TJ ≤ 2.8. 16 D-type objects have been identified in this population, distributed on orbits with an average TJ = 2.65 ± 0.6. Using two dynamical criteria, together with the comet-like spectral classification as an identification method and by applying an observational bias correction, we estimate that the fraction of NEOs with a cometary nature and H ∈ (14, 21) mag has the lower and upper bounds (1.5 ± 0.15) and (10.4 ± 2.2) per cent. Additionally, our observations show that all extreme cases of low-perihelion asteroids (q ≤ 0.3 au) belong to S-complex.
Modelling type 1 quasar colours in the era of Rubin and Euclid
Authors: Temple Matthew J , Hewett Paul C , Banerji Manda
Published: September 2021

We construct a parametric SED model which is able to reproduce the average observed SDSS–UKIDSS–WISE quasar colours to within one-tenth of a magnitude across a wide range of redshift (0 < z < 5) and luminosity (−22 > Mi > −29). This model is shown to provide accurate predictions for the colours of known quasars which are less luminous than those used to calibrate the model parameters, and also those at higher redshifts z > 5. Using a single parameter, the model encapsulates an up-to-date understanding of the intra-population variance in the rest-frame ultraviolet and optical emission lines of luminous quasars. At fixed redshift, there are systematic changes in the average quasar colours with apparent i-band magnitude, which we find to be well explained by the contribution from the host galaxy and our parametrization of the emission-line properties. By including redshift as an additional free parameter, the model could be used to provide photometric redshifts for individual objects. For the population as a whole we find that the average emission line and host-galaxy contributions can be well described by simple functions of luminosity which account for the observed changes in the average quasar colours across 18.1 < iAB < 21.5. We use these trends to provide predictions for quasar colours at the luminosities and redshifts which will be probed by the Rubin Observatory LSST and ESA-Euclid wide survey. The model code is applicable to a wide range of upcoming photometric and spectroscopic surveys, and is made publicly available.
On the constraints of galaxy assembly bias in velocity space
Authors: McCarthy Kevin Spencer , Zheng Zheng , Guo Hong , Luo Wentao , Lin Yen-Ting
Published: September 2021

If the formation of central galaxies in dark matter haloes traces the assembly history of their host haloes, in haloes of fixed mass, central galaxy clustering may show dependence on properties indicating their formation history. Such a galaxy assembly bias effect has been investigated previously, with samples of central galaxies constructed in haloes of similar mass and with mean halo mass verified by galaxy lensing measurements, and no significant evidence of assembly bias is found from the analysis of the projected two-point correlation functions of early- and late-forming central galaxies. In this work, we extend the investigation of assembly bias effect from real space to redshift (velocity) space, with an extended construction of early- and late-forming galaxies. We carry out halo occupation distribution modelling to constrain the galaxy–halo connection to see whether there is any sign of the effect of assembly bias. We find largely consistent host halo mass for early- and late-forming central galaxies, corroborated by lensing measurements. The central velocity bias parameters, which are supposed to characterize the mutual relaxation between central galaxies and their host haloes, are inferred to overlap between early- and late-forming central galaxies. However, we find a large amplitude of velocity bias for early-forming central galaxies (e.g. with central galaxies moving at more than 50 per cent that of dark matter velocity dispersion inside host haloes), which may signal an assembly bias effect. A large sample with two-point correlation functions and other clustering measurements and improved modelling will help reach a conclusive result.
The dust and gas environment of comet 8P/Tuttle
Authors: Gutiérrez Pedro J , Lara Luisa M , Moreno Fernando
Published: September 2021

Comet 8P/Tuttle has been selected as a possible backup target for the Comet Interceptor mission (ESA). This comet was observed intensively during its previous perihelion passage, in 2008 January. From those observations, important information was obtained about the physical properties of the nucleus and coma. This study focuses on the coma of 8P/Tuttle using visible spectra and images to derive gas and dust production rates. The production rates obtained suggest that this comet can be considered as ‘typical’ concerning the C2/CN and C3/CN ratios, although, depending on the criteria adopted, it could be defined as C3 depleted. NH2 production rates suggest an enrichment of this molecule. Visible and infrared images have been analysed using a Monte Carlo dust tail model. At comparatively large heliocentric distances, the coma is characterized by a dust-to-water ratio around or less than 1. Nevertheless, when the comet approaches perihelion, and the subsolar latitude crosses the equator, the coma dust-to-water ratio increases significantly, reaching values larger than six. Such a high dust-to-gas ratio around perihelion suggests that the nucleus of 8P/Tuttle is also ‘typical’ regarding the refractory content, considering the comparatively high values of that magnitude estimated for different comets.