bluuebunny/crossref_metadata_2025 huggingface dataset:
The mutagenic effect of tobacco smoke on male fertility
Authors: Omolaoye Temidayo S. , El Shahawy Omar , Skosana Bongekile T. , Boillat Thomas , Loney Tom , du Plessis Stefan S
Published: September 2021

Despite the association between tobacco use and the harmful effects on general health as well as male fertility parameters, smoking remains globally prevalent. The main content of tobacco smoke is nicotine and its metabolite cotinine. These compounds can pass the blood-testis barrier, which subsequently causes harm of diverse degree to the germ cells. Although controversial, smoking has been shown to cause not only a decrease in sperm motility, sperm concentration, and an increase in abnormal sperm morphology, but also genetic and epigenetic aberrations in spermatozoa. Both animal and human studies have highlighted the occurrence of sperm DNA-strand breaks (fragmentation), genome instability, genetic mutations, and the presence of aneuploids in the germline of animals and men exposed to tobacco smoke. The question to be asked at this point is, if smoking has the potential to cause all these genetic aberrations, what is the extent of damage? Hence, this review aimed to provide evidence that smoking has a mutagenic effect on sperm and how this subsequently affects male fertility. Additionally, the role of tobacco smoke as an aneugen will be explored. We furthermore aim to incorporate the epidemiological aspects of the aforementioned and provide a holistic approach to the topic.
Effect of inherent microcrack populations on rock tensile fracture behaviour: numerical study based on embedded discontinuity finite elements
Authors: Saksala Timo
Published: September 2021

Inherent microcrack populations have a significant effect on the fracture behaviour of natural rocks. The present study addresses this topic in numerical simulations of uniaxial tension and three-point bending tests. For this end, a rock fracture model based on multiple intersecting embedded discontinuity finite elements is developed. The inherent (pre-existing) microcrack populations are represented by pre-embedded randomly oriented discontinuity populations. Crack shielding (through spurious locking) is prevented by allowing a new crack to be introduced, upon violation of the Rankine criterion, in an element with an initial crack unfavourably oriented to the loading direction. Rock heterogeneity is accounted for by random clusters of triangular finite elements representing different minerals of granitic numerical rock. Numerical simulations demonstrate the strength lowering effect of initial microcrack populations. This effect is substantially stronger under uniaxial tension, due to the uniform stress state, than in semicircular three-point bending having a non-uniform stress state with a clear local maximum of tensile stress.
Intrapersonal and Interpersonal Sources of Resilience: Mechanisms of the Relationship Between Bullying Victimization and Mental Health Among Migrant Children in China
Authors: Cui Kunjie , Xie Han
Published: September 2021

Compared with their non-migrant peers, migrant children in China face major risks and challenges that may cause them to develop behavioral and psychological problems. Nevertheless, research has seldom addressed their victimization by bullies and its association with their mental health outcomes, much less the roles of intrapersonal and interpersonal sources of resilience in that relationship. In response, this study was designed to examine how bullying victimization both directly and indirectly influences migrant children’s mental health through intrapersonal and interpersonal sources of resilience. Data were collected from a school-based multistage random sample of 1,132 migrant children in Grades 4–9 (mean age = 11.88 years, range = 8–17 years; boys = 55.6%) attending public schools in Nanjing and private schools in Guangzhou, China. Structural equation modeling performed with Amos 25.0 revealed that both intrapersonal and interpersonal sources of resilience mediated the effect of bullying victimization on migrant children’s mental health, albeit intrapersonal sources demonstrated a slightly stronger mediation effect. The results thus suggest that social workers and educators should provide effective prevention and intervention strategies that promote intrapersonal and interpersonal sources of resilience among migrant children in China.
Social Innovation and Health-Related Well-Being of Left-Behind Children: Evidence from an Intelligent Robot Project in China
Authors: Xie Xiaoxia , Chen Yafan , Cheung Shannon , Huang Chien-Chung
Published: September 2021

In China, rural children, compared to their urban counterparts, are disadvantaged by less parental care and limited access to educational resources. This can have dire consequences for their health-related well-being during a vulnerable and formative stage of the life course. Quality of life (QOL) has been increasingly used as an indicator of individuals’ well-being. QOL studies have primarily been conducted in Western contexts, but there is relatively less knowledge on QOL in the Chinese context, particularly for rural left-behind children (LBC). This study analyzed the effects of a socially innovative product – intelligent robots by the Li Ensan Charity Foundation – on the health-related well-being of rural LBC in China. Children who used the robots and reported higher satisfaction with the use experienced positive effects on QOL than their counterparts.. We discussed the implications of these results in the context of micro- and macro-level practice.
Inherent paradoxes in the shift to autonomous solutions provision: a multilevel investigation of the shipping industry
Authors: Sandvik Håkon Osland , Sjödin David , Brekke Thomas , Parida Vinit
Published: September 2021

Transforming a traditional industry by adopting autonomous solutions is complex, generating paradoxical tensions on multiple aggregate levels. We undertake an in-depth case study of a leading maritime autonomous solutions provider and its ecosystem partners. We apply the paradox lens using thematic analysis. Our research contributes to the digital servitization literature by identifying six paradoxes inherent in the shift to autonomous solutions, nested in the micro, meso, and macro levels. We develop a multilevel framework of organizational paradoxes, delineating cascading effects of paradoxes across levels. We offer valuable insights for providers to integrate multilevel perspectives into the shift to autonomous solutions.
Reactive oxygen species, nitric oxide and plant cell death associated with caspase-like protease activity during somatic embryogenesis in Fraxinus mandshurica
Authors: Wang Hao , Zhang Dongyan , Fernández-Lorenzo Juan Luis , Shen Hailong , Yang Ling
Published: September 2021

Programmed cell death occurs in browning explants of Fraxinus mandshurica during somatic embryogenesis, but the underlying mechanism is unclear. In this study, single cotyledons of zygotic embryos of F. mandshurica were used as explants. Mitochondrial structure and function, caspase-3-like protease activity, hydrogen peroxide metabolism, and nitric oxide accumulation induced by high concentrations of sucrose and plant growth regulators were studied. The results show that plant growth regulators induced somatic embryogenesis and also promoted explant browning. High sucrose concentrations had similar effects. High concentrations of sucrose and plant growth regulators led to the accumulation of hydrogen peroxide and nitric oxide which induced changes in mitochondrial structure and function such as modifications in mitochondrial morphology, increased membrane permeability, decreased membrane potential, and the release of cytochrome c into the cytoplasm. An increase in caspase-3-like protease activity triggered programmed cell death in some browning explant cells. During somatic embryogenesis there were increased activities of superoxide dismutase, peroxidase, and catalase, which are associated with hydrogen peroxide metabolism and jointly maintain reactive oxygen species levels. Intracellular nitric oxide synthase and nitrate reductase activities were not significantly correlated with nitric oxide content. Instead, intracellular nitric oxide may be derived from non-enzymatic reactions. Our results indicate that hydrogen peroxide and nitric oxide may function as signals, playing key roles in somatic embryogenesis and programmed cell death of explant cells of F. mandshurica. The interaction between nitric oxide and reactive oxygen species determines the occurrence of programmed cell death in explant cells; somatic embryogenesis and programmed cell death are positively regulated by hydrogen peroxide. However, the regulation of nitric oxide is complex.
Age and sex effects on advanced white matter microstructure measures in 15,628 older adults: A UK biobank study
Authors: Lawrence Katherine E. , Nabulsi Leila , Santhalingam Vigneshwaran , Abaryan Zvart , Villalon-Reina Julio E. , Nir Talia M. , Ba Gari Iyad , Zhu Alyssa H. , Haddad Elizabeth , Muir Alexandra M. , Laltoo Emily , Jahanshad Neda , Thompson Paul M.
Published: September 2021

A comprehensive characterization of the brain’s white matter is critical for improving our understanding of healthy and diseased aging. Here we used diffusion-weighted magnetic resonance imaging (dMRI) to estimate age and sex effects on white matter microstructure in a cross-sectional sample of 15,628 adults aged 45–80 years old (47.6% male, 52.4% female). Microstructure was assessed using the following four models: a conventional single-shell model, diffusion tensor imaging (DTI); a more advanced single-shell model, the tensor distribution function (TDF); an advanced multi-shell model, neurite orientation dispersion and density imaging (NODDI); and another advanced multi-shell model, mean apparent propagator MRI (MAPMRI). Age was modeled using a data-driven statistical approach, and normative centile curves were created to provide sex-stratified white matter reference charts. Participant age and sex substantially impacted many aspects of white matter microstructure across the brain, with the advanced dMRI models TDF and NODDI detecting such effects the most sensitively. These findings and the normative reference curves provide an important foundation for the study of healthy and diseased brain aging.
Adaptive aerodynamic part feeding enabled by genetic algorithm
Authors: Blankemeyer Sebastian , Kolditz Torge , Busch Jan , Seitz Melissa , Nyhuis Peter , Raatz Annika
Published: September 2021

Aerodynamic feeding systems represent one possibility to meet the challenges of part feeding for automated production in terms of feeding performance and flexibility. The aerodynamic feeding system investigated in this article is already able to adapt itself to different workpieces using a genetic algorithm. However, due to the operating principle, the system is susceptible to changes in environmental conditions such as air pressure and pollution (e.g. dust). To minimise the effect of ambient influences, the system must be enabled to detect changes in the feeding rate and react autonomously by adapting the system’s adjustment parameters. In this work, based on pre-identified factors interfering with the aerodynamic orientation process, a new approach is developed to react to changes of the ambient conditions during operation. The presented approach makes us of an alternating sequence of monitoring and corrective algorithms. The monitoring algorithm measures the ratio of correctly oriented parts to the total number of fed parts of the process and triggers the corrective algorithm if necessary. Simulated and experimental results both show that an increased feeding rate can be achieved in varying conditions. Furthermore, it is shown that integrating both known process and parameter information can reduce the time for re-parametrisation of the feeding system.
Factors affecting the mother’s choice of infant feeding method in Poland: a cross-sectional preliminary study in Poland
Authors: Rozensztrauch Anna , Klaniewska Magdalena , Berghausen-Mazur Marta
Published: September 2021

Background

The World Health Organization identifies exclusive breastfeeding as the gold standard for child nutrition. Breastfeeding provides many benefits to both the baby and the mother. First days after birth are crucial for breastfeeding and determining its further path. Unfortunately, very often it is also the time of facing the first breastfeeding problems. The aim of this study was to analyse selected factors influencing a mother’s decision to breastfeed.

Methods

This is a cross-sectional study conducted between March 2019 and November 2019 in selected Polish maternity wards. Data were collected through completion of author’s questionnaire and a standardised questionnaire and the Multidimensional Perceived Social Support Scale and also through informal interviews with mothers. During statistical analysis, the chi-square test of independence and the Kolmogorov–Smirnov test as well as the non-parametric Mann–Whitney U test in addition to Fisher’s exact test were performed.

Results

The results showed that there is no correlation between the mode of delivery and the mother’s choice of infant feeding method. Knowledge of the benefits of breastfeeding and received support affects the mother’s decision on infant feeding method. The study also showed that the 83% of newborns were put to the breast within the first 2 h after birth. However, only 58% continued to be breastfed in the subsequent days. As many as 42% of the newborns were supplemented with formula despite early initiation of breastfeeding. Analyses showed that exclusive breastfeeding was more often chosen by mothers with higher education. And the most common breastfeeding problem reported by 62% of the respondents was perceived insufficient milk supply and also breastfeeding pain, reported in 48.5% mothers.

Conclusions

It is extremely important to continually promote breastfeeding among women. The role of midwives is crucial in this regard, as they should encourage the initiation of breastfeeding, support mothers during the perinatal and postnatal periods, and increase their sense of competence and confidence in their ability to breastfeed. Accessible, professional, and empathetic support can help reduce the number of women supplementing with modified milk. Undoubtedly, the postpartum period is important for breastfeeding outcomes, but it is significant that breastfeeding education and promotion begin during pregnancy.
The Role of IgE in Upper and Lower Airway Disease: More Than Just Allergy!
Authors: Gevaert Philippe , Wong Kit , Millette Lauren A. , Carr Tara F.
Published: September 2021

Immunoglobulin E (IgE) is a well-known key factor in allergic airway disease; however, its central role in non-allergic airway inflammation is often underestimated. In some airway diseases, IgE is produced as a result of allergic sensitization. However, in others, IgE production occurs despite the lack of a specific allergen. Although multiple pathways contribute to the production of IgE in airway disease, it is its activity in mediating the inflammatory response that is associated with disease. Therefore, an understanding of IgE as the unifying component of upper and lower airway diseases has important implications for both diagnosis and treatment. Understanding the role of IgE in each upper and lower airway disease highlights its potential utility as a diagnostic marker and therapeutic target. Further classification of these diseases by whether they are IgE mediated or non–IgE mediated, rather than by the existence of an underlying allergic component, accounts for both systemic and localized IgE activity. Improvements in diagnostic methodologies and standardization of clinical practices with this classification in mind can help identify patients with IgE-mediated diseases. In doing so, this group of patients can receive optimal care through targeted anti-IgE therapeutics, which have already demonstrated efficacy across numerous IgE-mediated upper and lower airway diseases.
Pre- versus post-operative untargeted plasma nuclear magnetic resonance spectroscopy metabolomics of pheochromocytoma and paraganglioma
Authors: Bliziotis Nikolaos G. , Kluijtmans Leo A. J. , Soto Sebastian , Tinnevelt Gerjen H. , Langton Katharina , Robledo Mercedes , Pamporaki Christina , Engelke Udo F. H. , Erlic Zoran , Engel Jasper , Deutschbein Timo , Nölting Svenja , Prejbisz Aleksander , Richter Susan , Prehn Cornelia , Adamski Jerzy , Januszewicz Andrzej , Reincke Martin , Fassnacht Martin , Eisenhofer Graeme , Beuschlein Felix , Kroiss Matthias , Wevers Ron A. , Jansen Jeroen J. , Deinum Jaap , Timmers Henri J. L. M.
Published: September 2021

Purpose

Pheochromocytomas and Paragangliomas (PPGL) result in chronic catecholamine excess and serious health complications. A recent study obtained a metabolic signature in plasma from PPGL patients; however, its targeted nature may have generated an incomplete picture and a broader approach could provide additional insights. We aimed to characterize the plasma metabolome of PPGL patients before and after surgery, using an untargeted approach, and to broaden the scope of the investigated metabolic impact of these tumors.

Design

A cohort of 36 PPGL patients was investigated. Blood plasma samples were collected before and after surgical tumor removal, in association with clinical and tumor characteristics.

Methods

Plasma samples were analyzed using untargeted nuclear magnetic resonance (NMR) spectroscopy metabolomics. The data were evaluated using a combination of uni- and multi-variate statistical methods.

Results

Before surgery, patients with a nonadrenergic tumor could be distinguished from those with an adrenergic tumor based on their metabolic profiles. Tyrosine levels were significantly higher in patients with high compared to those with low BMI. Comparing subgroups of pre-operative samples with their post-operative counterparts, we found a metabolic signature that included ketone bodies, glucose, organic acids, methanol, dimethyl sulfone and amino acids. Three signals with unclear identities were found to be affected.

Conclusions

Our study suggests that the pathways of glucose and ketone body homeostasis are affected in PPGL patients. BMI-related metabolite levels were also found to be altered, potentially linking muscle atrophy to PPGL. At baseline, patient metabolomes could be discriminated based on their catecholamine phenotype.
AI invading the workplace: negative emotions towards the organizational use of personal virtual assistants
Authors: Hornung Olivia , Smolnik Stefan
Published: September 2021

Personal virtual assistants (PVAs) based on artificial intelligence are frequently used in private contexts but have yet to find their way into the workplace. Regardless of their potential value for organizations, the relentless implementation of PVAs at the workplace is likely to run into employee resistance. To understand what motivates such resistance, it is necessary to investigate the primary motivators of human behavior, namely emotions. This paper uncovers emotions related to organizational PVA use, primarily focusing on threat emotions. To achieve our goal, we conducted an in-depth qualitative study, collecting data from 45 employees in focus-group discussions and individual interviews. We identified and categorized emotions according to the framework for classifying emotions Beaudry and Pinsonneault (2010) designed. Our results show that loss emotions, such as dissatisfaction and frustration, as well as deterrence emotions, such as fear and worry, constitute valuable cornerstones for the boundaries of organizational PVA use.
Multi agents simulation of justice trials to support control management and reduction of civil trials duration
Authors: Di Martino Beniamino , Esposito Antonio , Colucci Cante Luigi
Published: September 2021

Thanks to the digitalization of Civil Legal Processes that has been carried out in Italy since 2005, a consistent flow of data has been generated regarding all phases of Civil Trials. The Italian Ministry of Justice has recognized the opportunity to better assess the quality of Courts’ management, seeking ways to implement Decision Support Systems to aid the work of Court Presidents. In collaboration with the Court of Livorno, which has provided data and case studies, KPIs and indicators have been developed, and have been later used within an Agent-based simulation framework to assess the behaviour of Chancellors and Judges in response to Court Presidents’ decisions, and in particular to verify the effects of such decision on Processes’ duration. This paper presents the Agent-based simulation approaches adopted to predict the effects of Presidents’ decisions, by taking in consideration the behaviour of Chancellors and Judges, derived from the examination of past Trials, whose aspects have been recorded by the Court’s digital system.
Natural radioactivity of rocks from the historic Jeroným Mine in the Czech Republic
Authors: Malczewski Dariusz , Dziurowicz Maria , Kalab Zdenek , Rösnerová Marketa
Published: September 2021

This study reports the natural radioactivity of characteristic rocks found in the historic Jeroným Mine of the Czech Republic as measured under the laboratory conditions. The rocks analyzed included granites and schists weathered to varying degrees and collected from different levels of the underground workings of the Jeroným Mine. The mine itself has been subject to metal extraction (mainly tin and tungsten) since the sixteenth century and has recently been developed as a cultural and scientific attraction open to the public. Activity concentrations of 40K, 232Th and 238U were measured from nine rock samples using gamma-ray spectrometry. The activity concentrations of 40K varied from 595 Bq kg−1 to 1244 Bq kg−1, while 232Th varied from 25 Bq kg−1 to 55 Bq kg−1. The activities associated with 238U ranged from 46 Bq kg−1 to 386 Bq kg−1. The measured activities were used to estimate two radiation hazard indices typically applied to building materials, the activity concentration index I and the external hazard index Hex. Mean respective values of 1.02 and 0.77 for I and Hex indicate that the rocks found in the Jeroným Mine meet radiological safety standards for building materials and do not pose a risk to potential tourists and staff.
Mindfulness in Relation to Diet Quality in Adults with Type 1 and Type 2 Diabetes: Results from Diabetes MILES-The Netherlands
Authors: Liu Shengxin , Nyklíček Ivan , Pouwer Frans , Speight Jane , Bot Mariska , Nefs Giesje , Soedamah-Muthu Sabita S.
Published: September 2021

Objectives

The objectives of this study were to investigate the associations of dispositional mindfulness and its facets with diet quality in Dutch adults with type 1 diabetes and type 2 diabetes and to evaluate the potential mediating role of emotional distress in these associations.

Methods

This was a cross-sectional study using data from the Diabetes MILES-The Netherlands. In total, 296 adults with type 1 diabetes and 364 with type 2 diabetes completed questionnaires. We assessed dispositional mindfulness by the Five Facet Mindfulness Questionnaire-Short Form, including total mindfulness and five facets: observing, describing, acting with awareness, being non-judgmental, and being non-reactive, and diet quality by the Dutch Healthy Diet 2015-index. Linear regression models were used to estimate the association. Mediation effects of depressive symptoms, anxiety symptoms, and diabetes-related distress were evaluated using the PROCESS macro with bias-corrected bootstrapped confidence intervals.

Results

Higher scores on the total mindfulness (β = 0.14, p = 0.02) and the observing facet (β = 0.15, p = 0.01) were significantly associated with higher diet quality in people with type 1 diabetes only, after adjustment for demographic factors. These associations were not mediated by depressive symptoms, anxiety symptoms, or diabetes-related distress. In adults with type 1 diabetes (but not type 2), higher dispositional mindfulness levels were associated with more optimal diet quality.

Conclusions

Higher mindfulness in general and observing in particular were related to a healthier diet with higher quality in Dutch adults with type 1 diabetes. Further longitudinal studies are warranted to understand the temporal relationship between mindfulness and diet quality.
Predicting coastal urban floods using artificial neural network: The case study of Macau, China
Authors: Dai Weijun , Cai Zhiming
Published: September 2021

Using data-driven models to predict floods in advance is one of the current effective methods and hot researches to reduce urban flood disasters. In order to improve the prediction accuracy, it is necessary to select the appropriate flood hazard factors and the number of training samples to construct the prediction model. In our current research, an artificial neural network (i.e., the back-propagation neural network, BPNN) model was developed to predict the flood depth in the next hour. A case study of the urban flood during six typhoons in Macau of China was conducted to prove the performance of the proposed model. The flood depth was collected as output; after analyzing their correlation to the flood typhoon optimum track, urban weather, tides, geographic height and water depth increment of the submerged area were used as input. As a result, four models trained with different sample numbers were developed for training and testing. The model performances were examined using average absolute error, root mean square error and the coefficient of determination. The results show that in this case study, the 30-min scale model provides reliable predictions and can provide useful decision support for the prevention and mitigation of flood disasters in coastal urban.
Vascularization of Microvascular Fragment Isolates from Visceral and Subcutaneous Adipose Tissue of Mice
Authors: Später Thomas , Marschall Julia E. , Brücker Lea K. , Nickels Ruth M. , Metzger Wolfgang , Menger Michael D. , Laschke Matthias W.
Published: September 2021

Background:

Adipose tissue-derived microvascular fragments (MVF) represent effective vascularization units for tissue engineering. Most experimental studies in rodents exclusively use epididymal adipose tissue as a visceral fat source for MVF isolation. However, in future clinical practice, MVF may be rather isolated from liposuctioned subcutaneous fat tissue of patients. Therefore, we herein compared the vascularization characteristics of MVF isolates from visceral and subcutaneous fat tissue of murine origin.

Methods:

MVF isolates were generated from visceral and subcutaneous fat tissue of donor mice using two different enzymatic procedures. For in vivo analyses, the MVF isolates were seeded onto collagen-glycosaminoglycan scaffolds and implanted into full-thickness skin defects within dorsal skinfold chambers of recipient mice.

Results:

By means of the two isolation procedures, we isolated a higher number of MVF from visceral fat tissue when compared to subcutaneous fat tissue, while their length distribution, viability and cellular composition were comparable in both groups. Intravital fluorescence microscopy as well as histological and immunohistochemical analyses revealed a significantly reduced vascularization of implanted scaffolds seeded with subcutaneous MVF isolates when compared to implants seeded with visceral MVF isolates. Light and scanning electron microscopy showed that this was due to high amounts of undigested connective tissue within the subcutaneous MVF isolates, which clogged the scaffold pores and prevented the interconnection of individual MVF into new microvascular networks.

Conclusion:

These findings indicate the need for improved protocols to generate connective tissue-free MVF isolates from subcutaneous fat tissue for future translational studies.
Comprehensive review of tribometer dynamics-Cycle-based data analysis and visualization
Authors: Prost Josef , Boidi Guido , Lebersorger Thomas , Varga Markus , Vorlaufer Georg
Published: September 2021

Tribologists often rely on triboexperiments to investigate factors that affect a tribosystem. The inherent dynamic behavior of the respective tribometer setups and its effect on data interpretation remain often unknown. In this study, a comprehensive analysis of sensor data obtained from lubricated and dry triboexperiments is performed. Data are generated on a pin-on-disc test rig with a silicon nitride ball on a steel disc contact with a rotation frequency of ~3 Hz. High-speed acquisition of sensor data up to 5 kHz is performed to resolve changes in the data within individual cycles. The characteristic frequencies of the system and their temporal evolution are determined via time-frequency analysis, which reveals periodic patterns in the sensor data. Cycle-based data evaluation allows the detection of localized events and changes during an operation and considerably reduces the apparent measurement uncertainty, as compared with an unreduced dataset. The data analysis and visualization routines presented herein may serve as a prototype for further application to tribometer setups.
The Chinese Inland-Coastal Inequality: The Role of Human Capital and the 2007–2008 Crisis Watershed
Authors: Felice Emanuele , Odoardi Iacopo , D’Ingiullo Dario
Published: September 2021

We investigate the role of human capital (HC) in the Chinese inland-coastal inequality and, related to this, how the consequences of the 2007–2008 crisis may induce China to re-focus its development path on HC. We compare panel data analyses for two periods (1998–2008 and 2009–2017) for two diverging groups of provinces (the richer/coastal and the relatively poor/inland areas). In the first period, the economic strengths that influenced the Chinese take-off and the dualism are confirmed. However, the results show that an evolution in local economic endowments is taking place: first, HC has a more evident economic effect after the crisis only in the inland provinces; second, the development path of the inland area is changing, with an evolution towards more productive sectors which can favor higher returns to HC.
Modelling Investigation of the Thermal Treatment of Ash-Contaminated Particulate Filters
Authors: Lao Chung Ting , Akroyd Jethro , Smith Alastair , Morgan Neal , Lee Kok Foong , Nurkowski Daniel , Kraft Markus
Published: September 2021

This paper investigates the impact of thermal treatment on the pressure drop of particulate filters containing ash deposits. A one-dimensional model has been developed and applied to describe the deposition of soot and ash particles, and estimate the spatial distribution of the deposits in such filters. Phenomenological models have been developed to describe the potential sintering and cracking of the ash deposits caused by thermal treatment of the filter. The model results are in good agreement with experimental measurements of the reduction in the pressure drop in thermally treated filters. It was found that crack formation in the ash layer can lead to significant reduction of the pressure drop at relatively low temperatures. Sintering of ash deposits in the wall and the ash plug also contributes towards a decrease in filter pressure drop at higher temperatures. This work is the first attempt to model the impact of the thermal treatment of ash in particulate filters in order to support the development of future ash management strategies. The cracking of the ash layer during the thermal treatment has been identified to be the most critical effect for pressure drop reduction.
On off-diagonal decay properties of the generalized Stokes semigroup with bounded measurable coefficients
Authors: Tolksdorf Patrick
Published: September 2021

We investigate off-diagonal decay properties of the generalized Stokes semigroup with bounded measurable coefficients on $$\mathrm {L}^2_{\sigma } ({\mathbb {R}}^d)$$

L

σ
2

(

R

d

)

. Such estimates are well-known for elliptic equations in the form of pointwise heat kernel bounds and for elliptic systems in the form of integrated off-diagonal estimates. On our way to unveil this off-diagonal behavior we prove resolvent estimates in Morrey spaces $$\mathrm {L}^{2 , \nu } ({\mathbb {R}}^d)$$

L

2
,
ν

(

R

d

)

with $$0 \le \nu < 2$$

0
≤
ν
<
2

.
Measuring the Deflection of the Vertical via Local Reference Point Surveying and Pointing Calibration of a VLBI Telescope: A Case Study at the Urumqi Station
Authors: Zhang Zhibin , Ma Xiaohui , Sun Zhongmiao , Zhang Ali , Yuan Ye , Sun Zhengxiong
Published: September 2021

According to Newton's law of universal gravitation, the movement of matter and the change in density cause a gravitational variation. Due to the anisotropic distribution of matter, the vertical and the normal directions at a point on the ground are probably inconsistent, which is referred to as the deflection of the vertical (DOV) and is indispensable to astrogeodetic and geophysics research. Two new non‐optical methods, including small network transformation and azimuth‐axis inclination inversion, are proposed to determine the DOV at a very long baseline interferometry (VLBI) telescope at the Urumqi station. A generalized expression of the pointing calibration model considering axis‐related errors is also presented. Therefore, the pointing calibration model and indirect model used for reference point (RP) determination are unified by redefining their coordinate system, angle direction, and axis‐related errors. The DOV given by the small network transformation agrees well with the DOVs determined by the real surveying and other different models. Due to the possible asymmetric coverage of calibrating sources in the north‐south direction in antenna pointing calibration, the north‐south DOV component based on azimuth‐axis inclination inversion differs from the surveyed value. However, the west‐east DOV component fits well in both direction and magnitude. The proposed methods enable the VLBI telescope to sense the direction of the local plumb line by introducing local leveling. We also establish the connections among VLBI delay observation, RP determination, and telescope pointing calibration, which has a benefit to multi‐tech systematic error identification, monitoring, and correction. The research indicates that telescope point calibration can also be taken as a regular technique to monitor systematic error.
Mission to Venus Could Help Solve an Atmospheric Mystery
Authors: Cordova Jaime
Published: September 2021

NASA’s recently announced DAVINCI+ mission to Venus will probe the planet’s atmosphere, hoping to shed light on the unknown dark patches that surround the planet.
To Understand Hunger in Sub-Saharan Africa, Consider Both Climate and Conflict
Authors: Fritts Rachel
Published: September 2021

Warfare exacerbates the impacts of drought to produce food insecurity crises that last long after the drought has passed, new research documents.
Modeling Kelvin‐Helmholtz Instability at the High‐Latitude Boundary Layer in a Global Magnetosphere Simulation
Authors: Michael A. T. , Sorathia K. A. , Merkin V. G. , Nykyri K. , Burkholder B. , Ma X. , Ukhorskiy A. Y. , Garretson J.
Published: September 2021

The Kelvin‐Helmholtz instability at the magnetospheric boundary plays a crucial role in solar wind‐magnetosphere‐ionosphere coupling, particle entry, and energization. The full extent of its impact has remained an open question due, in part, to global models without sufficient resolution to capture waves at higher latitudes. Using global magnetohydrodynamic simulations, we investigate an event when the Magnetospheric Multiscale (MMS) mission observed periodic low‐frequency waves at the dawn‐flank, high‐latitude boundary layer. We show the layer to be unstable, even though the slow solar wind with the draped interplanetary magnetic field is seemingly unfavorable for wave generation. The simulated velocity shear at the boundary is thin () and requires commensurately high spatial resolution. These results, together with MMS observations, confirm for the first time in fully three‐dimensional global geometry that KH waves can grow in this region and thus can be an important process for energetic particle acceleration, dynamics, and transport.
Recent Increases in Exposure to Extreme Humid‐Heat Events Disproportionately Affect Populated Regions
Authors: Rogers Cassandra D. W. , Ting Mingfang , Li Cuihua , Kornhuber Kai , Coffel Ethan D. , Horton Radley M. , Raymond Colin , Singh Deepti
Published: September 2021

Extreme heat research has largely focused on dry‐heat, while humid‐heat that poses a substantial threat to human‐health remains relatively understudied. Using hourly high‐resolution ERA5 reanalysis and HadISD station data, we provide the first spatially comprehensive, global‐scale characterization of the magnitude, seasonal timing, and frequency of dry‐ and wet‐bulb temperature extremes and their trends. While the peak dry‐ and humid‐heat extreme occurrences often coincide, their timing differs in climatologically wet regions. Since 1979, dry‐ and humid‐heat extremes have become more frequent over most land regions, with the greatest increases in the tropics and Arctic. Humid‐heat extremes have increased disproportionately over populated regions (∼5.0 days per‐person per‐decade) relative to global land‐areas (∼3.6 days per‐unit‐land‐area per‐decade) and population exposure to humid‐heat has increased at a faster rate than to dry‐heat. Our study highlights the need for a multivariate approach to understand and mitigate future harm from heat stress in a warming world.
Slippery Bottom Boundary Layers: The Loss of Energy From the General Circulation by Bottom Drag
Authors: Ruan Xiaozhou , Wenegrat Jacob O. , Gula Jonathan
Published: September 2021

Bottom drag is believed to be one of the key mechanisms that remove kinetic energy from the ocean's general circulation. However, large uncertainty still remains in global estimates of bottom drag dissipation. One significant source of uncertainty comes from the velocity structures near the bottom where the combination of sloping topography and stratification can reduce the mean flow magnitude, and thus the bottom drag dissipation. Using high‐resolution numerical simulations, we demonstrate that previous estimates of bottom drag dissipation are biased high because they neglect velocity shear in the bottom boundary layer. The estimated bottom drag dissipation associated with geostrophic flows over the continental slopes is at least 56% smaller compared with prior estimates made using total velocities outside the near‐bottom layer. The diagnostics suggest the necessity of resolving the bottom boundary layer structures in coarse‐resolution ocean models and observations in order to close the global kinetic energy budget.
Seismic Reflection and Electrical Resistivity Imaging Support Pre‐Quaternary Glaciation in the Rocky Mountains (Unaweep Canyon, Colorado)
Authors: Patterson Anna , Behm Michael , Chwatal Werner , Flores‐Orozco Adrian , Wang Yichuan , Soreghan Gerilyn S.
Published: September 2021

Unaweep Canyon (Uncompahgre Plateau, Colorado) represents an enigmatic landscape with a complex evolution. Interpretations for its origin have ranged from ancestral fluvial erosion in the late Cenozoic to glacial erosion in the Paleozoic, or some combination thereof, with significant implications for global climatic and large‐scale tectonic reconstructions. To address the conflicting interpretations, we acquired a high‐resolution seismic reflection profile to investigate the depth, structure, and sedimentary infill in the canyon. The data set is further complemented with an electrical resistivity survey. Integrated with other geophysical and geological data, the results show an overdeepened Precambrian basement with transverse U shape and support the hypothesis of a pre‐Quaternary glacial origin. Our data constitute the first detailed image of a buried pre‐Quaternary glacial valley in North America; if substantiated with core studies, these results have far‐reaching implications for our understanding of global ice houses as well as the tectonic conditions, enabling preservation of such systems.
Magnetospheric Multiscale Observations of an Expanding Oxygen Wave in Magnetic Reconnection
Authors: Kolstø Håkon Midthun , Norgren Cecilia , Hesse Michael , Chen Li‐Jen , Tenfjord Paul , Spinnangr Susanne Flø , Kwagala Norah
Published: September 2021

Heavier plasma species such as oxygen ions can have a large impact on the magnetic reconnection process. It has been hypothesized that the acceleration of demagnetized oxygen ions by the Hall electric field will lead to the formation of an oxygen wave that expands into the exhaust. By comparing data from NASA's Magnetospheric Multiscale mission to a fully kinetic particle‐in‐cell simulation, we can for the first time provide observational evidence of such an expanding oxygen wave. The wave is characterized by an oxygen jet consisting of cold ions directed toward the neutral sheet associated with a density cavity. This density cavity forms as the are subject to collective acceleration by the Hall electric field leaving behind a region of low‐density oxygen ions. Our results are important for the understanding of the role and effect of oxygen ions in magnetic reconnection.
Mineral Luminescence Observed From Space
Authors: Köhler Philipp , Fischer Woodward W. , Rossman George R. , Grotzinger John P. , Doughty Russell , Wang Yujie , Yin Yi , Frankenberg Christian
Published: September 2021

Methods developed to explore the luminescent properties of the moon facilitated the development of techniques to infer terrestrial solar‐induced chlorophyll fluorescence (SIF) from satellite instruments. While single SIF retrievals are inherently noisy, averaging many retrievals allows us to obtain highly accurate estimates. We analyzed several years of aggregated SIF data collected by the TROPOspheric Monitoring Instrument (TROPOMI) and the Orbiting Carbon Observatory‐2 (OCO‐2) over nonvegetated areas to explore the potential of SIF retrievals beyond the realm of photosynthesis. The fundamentally different retrievals at varying wavelengths in the near‐infrared reveal that about 10% of all barren surfaces are weakly luminescent, while a few areas luminesce strongly—amounts comparable to SIF from vegetation. By means of lithological maps, we attributed the strongest luminescence signals to exposed carbonate sedimentary rocks. Besides a detailed evaluation of the signal properties, we discussed implications for SIF data sets and other remote sensing products.
Enhanced Visibility of Subduction Slabs by the Formation of Dense Hydrous Phase A
Authors: Cai Nao , Qi Xintong , Chen Ting , Wang Siheng , Yu Tony , Wang Yanbin , Inoue Toru , Wang Duojun , Li Baosheng
Published: September 2021

Phase A (Mg7Si2O8(OH)6) is one of the important dense hydrous magnesium silicates in subducting slab, because it forms after the breakdown of antigorite serpentine and could be the dominant hydrous phase in the upper‐mantle deep slab for the water transportation into deep Earth. In this study, the compressional (P) and shear (S) wave velocities of phase A were measured at simultaneous pressure and temperature conditions up to 11 GPa and 1073 K. Combined with elastic properties of olivine and pyroxenes, we calculate the hydration effect on the velocities of harzburgite lithology in cold subduction zones throughout the depth ranges where phase A is thermodynamically stable. Our calculations suggest that the hydration increases both P‐ and S‐wave velocities of harzburgite; at ∼5 wt% hydration, its seismic detectability is enhanced by 1%–1.5% in velocity contrasts relative to its anhydrous counterpart.
Shock Mach Number Estimates Using Incomplete Measurements
Authors: Gedalin Michael , Russell Christopher T. , Dimmock Andrew P.
Published: September 2021

The Mach number is one of the most important parameters of collisionless shocks. The accuracy of its observational determination is compromised by several complications. Incomplete measurements of plasma parameters significantly contribute to the uncertainty, along with the errors of the normal determination. A set of CLUSTER observed shocks is analyzed using several methods for finding the shock normal and to circumvent the shortcomings of the plasma data. A relation between the maximum magnetic compression and the Alfvénic Mach number is established. It is proposed as a proxy for the Mach number estimate when measurements are incomplete.
Repeating Nontectonic Seasonal Stress Changes and a Possible Triggering Mechanism of the 2019 Ridgecrest Earthquake Sequence in California
Authors: Kim Jeonghyeop , Holt William E. , Bahadori Alireza , Shen Weisen
Published: September 2021

Here we characterize the 13‐year history of nontectonic horizontal strain anomalies across the regions surrounding Ridgecrest, CA, using cGPS data from January 2007. This time‐dependent model reveals a seasonality in the nontectonic strain anomalies and the associated Coulomb stress changes of ∼±0.5–2 kPa. In the area surrounding the epicenters of the 2019 Ridgecrest earthquake sequence of July, we find that the seasonal preseismic Coulomb stress changes peaked every early summer (May and June) during the last 13 years including during June 2019, a month prior to the large events. In addition, our statistical tests confirm that more strike‐slip earthquakes (Mw ≥ 2) occur during times when seasonal stress changes are increasing on right‐lateral faults in comparison with times when stresses are decreasing. These results suggest that the timing of the 2019 Ridgecrest earthquakes may have been modulated by nontectonic seasonal stress changes. The dynamic source of the seasonal nontectonic strain/stress anomalies, however, remains enigmatic. We discuss a possible combination of driving forces that may be attributable for the seasonal variations in nontectonic strain/stress anomalies, which captured in cGPS measurements.
Characterization of Irreversible Land Subsidence in the Yazd‐Ardakan Plain, Iran From 2003 to 2020 InSAR Time Series
Authors: Mirzadeh Sayyed Mohammad Javad , Jin Shuanggen , Parizi Esmaeel , Chaussard Estelle , Bürgmann Roland , Delgado Blasco Jose Manuel , Amani Meisam , Bao Han , Mirzadeh Seyyed Hossein
Published: September 2021

Groundwater extraction rates exceeding recharge are occurring throughout Iran to sustain industrial and agricultural activities, resulting in land deformation in many areas, particularly in the Yazd‐Ardakan Plain (YAP) in central Iran's dry and desert regions. In this study, Interferometric Synthetic Aperture Radar (InSAR) time series analysis and statistical models are applied to characterize the controls on land subsidence in the YAP from 2003 to 2020. Our results reveal the existence of a northwest‐southeast elongated area of 234.45 km2 experiencing subsidence at rates up to 15 cm/yr. In the YAP, the international Airport, railway, transit road, and several industrial and historical sites are threatened by the differential subsidence. Well data confirm that groundwater levels have decreased by 18 meters between 1974 and 2018, driving the compaction of sediments within the underlying aquifer system. Our statistical analysis shows that the thickness of a shallow, clay‐rich aquitard layer controls the extent of the observed subsidence and the Independent Component Analysis of the InSAR time series shows that inelastic compaction is dominated. This work reveals that current groundwater extraction practices in central Iran are not sustainable and result in permanent subsidence, ground fractures with impact on infrastructures, and a permanent decrease in water storage capacity.