bluuebunny/crossref_metadata_2025 huggingface dataset:
Researching impact of pressure re-distribution along the length of the track ground contacting area on resistance of the timber-hauling vehicles’ travel over snow
Authors: Klubnichkin Evgeny , Klubnichkin Vladislav , Erkhov Alexander , Alyabiev Alexey
Published: December 2019

The tracked timber-hauling vehicles which operate in the cutting areas having highly deforming soil, virgin snow in particular, feature significantly reduced performance due to rutting and caused frontal resistance.

Most logging enterprises harvest bulk timber in I and IV quarters of the year. However, deep snow during the second half of winter significantly reduces performance of the dragging tractors. Snow mostly affects performance of the feller-skidders and feller-bunchers which need to move from tree to tree to collect load while frequently crossing deep virgin snow.

Snow 0.4-0.6 m deep slightly resists to movement. However, when virgin snow is 0.7 m and deeper, the resistance rises sharply.

The tracked vehicle capacity to cross virgin snow can be improved in two ways: by improving friction properties and by reducing motion resistance. As is evident, more even distribution of track pressure and lack of pressure concentration under individual rollers will improve vehicle’s hauling power by reducing frontal resistance.

But as researcher M.G. Bekker stated, despite the fact that pressure distribution was considered one of the most important factors determining vehicle’s performance, the theoretical research and assessment of the problem was frequently neglected.

Today designers while designing new tracked dragging vehicles and assessing their performance refer to the researches made for industrial and agricultural tractors. This can be explained by few works dedicated to researching performance of the forest tracked vehicles. The design and operating conditions of the forest and non-forest vehicles are much different so that the results of research made for one type of vehicles cannot be applied to other types of vehicles.

That is why it is necessary to research the process of tracks’ impact on snow and pressure re-distribution due to snow reaction to justify parameters of the tracked undercarriage of the forest vehicles, provide optimized location of the gravity center and reduce motion resistance.

Our work is aimed to develop a method to estimate pressure distribution along the length of the track ground contacting area, test the method with experiment and provide recommendations to designers on improving oversnow performance of the forest tracked vehicles.
Autonomous control system prototype for GAZ A65R32
Authors: Tiurikov M. I. , Malinin N. V. , Evdokimova T. S. , Sinodkin A. A. , Fedosova L. O.
Published: December 2019

The article presents current state of development of autonomous control system prototype for GAZ A65R32. The solutions for mapping and localization, planning, used sensors, as well as the applied methods of computer vision and deep learning and the methods used to transfer data in the system are described.
Designed gearbox reliability assessment techniques based on the real one
Authors: Yusupov R.R. , Yarzhemsky A.D. , Alexeyev A.V. , Korchazhkin M.G. , Berdnikov L.A.
Published: December 2019

The paper shows the designed gearbox reliability assessment and analysis on the basis of the real one. The basic diagram has been analyzed as well as the units’ eventual failures. Based on the designed structural diagram of the SU gearbox reliability level has been estimated. The measures to raise the reliability level have been proposed.
Choice of metal materials for responsible parts and vehicle assemblies operating under the conditions of low temperatures
Authors: Kabaldin Y.G. , Khlybov A.A. , Anosov M.S. , Shatagin D.A. , Golovin A.A. , Scriabin M.D.
Published: December 2019

The purpose of the present study is to evaluate the cold resistance and develop an algorithm for selecting metals that are widely used for manufacturing critical parts and components of vehicles operating in a wide range of low temperatures.

To achieve this goal, the tests were made on impact bending of the studied metals in the temperature range of climatic cold, followed by the study of fractures of metal samples.

The studies were carried out using methods of optical and electron microscopy and fracto-graphic studies. During the study, data were obtained on the change in toughness, the mechanisms of metal destruction for a wide range of low temperatures, as well as the temperature of the viscous-brittle transition of the studied metals.

It has been found that materials with an FCC and HCP lattice exhibit greater resistance to fracture at low temperatures. It is shown that a change in the fracture mechanism is closely related to their crystal structure features and thermal conductivity.

As a result of the research, an algorithm for the selection of cold-resistant materials was developed, and on its basis- a program.
Estimate of elastomer elastic members’ impact on the vehicle ride quality, mobility and reliability in low temperatures
Authors: Molev Y. , Proshin D. , Stepanov E. , Maleev S. , Mavleev I. , Salakhov I.
Published: December 2019

Tough competition and stringent requirements force car producers to pay special attention to vehicle mobility and reliability in low temperatures. Suspension has a great impact on vehicle mobility and reliability together with tyres being a structural unit protecting the vehicle from the road dynamic effects. Enhancement of these car characteristics is possible by using advanced materials in the suspension structure. Such materials have the necessary strength characteristics, long service life and high resistance to external factors action. Elastomer elements application as suspension elastic-damping members is estimated in the paper. The estimate is based on calculation analysis, mathematic modelling and bench and road test results. A comparative analysis with existing structures has been carried out highlighting both advantages and disadvantages and types of vehicles where elastomers can be most efficiently used have been determined.
Hybridization Effects of S-glass fiber on Charpy impact resistance of carbon/aramid fiber reinforced epoxy composite laminates
Authors: Alsaadi Mohamad
Published: December 2019

The objective of the present research work is to investigate the Charpy impact behavior of intraply hybrid carbon/aramid fabric layers with S-glass fabric layers composite laminates for asymmetric and symmetric arrangements. The hybridization effects on Charpy impact characteristics for carbon/aramid with S-glass hybrid composite laminates were compared with those of carbon/aramid/epoxy composite laminates and S-glass/epoxy composite laminates. Deformation degree, impact energy and impact strength were strongly affected by the position and number of carbon/aramid layers in addition to the impact side direction due to variation of impact properties between carbon/aramid fibers and S-glass fibers. Using S-glass layers instead of carbon/aramid layers exhibited decreasing in the deformation level particularly for carbon/aramid side impact in addition to improve the impact strength of the hybrid composite.
Textured multilayered piezoelectric structures for energy conversion
Authors: Haugen Astri Bjørnetun , Ringgaard Erling , Levassort Franck
Published: December 2019

Piezoelectric materials are essential for the conversion between mechanical and electrical energy, for example in ultrasound imaging and vibrational energy harvesting. Here, we are making and exploring the effects of a new design: co-sintered multilayers with texture (grains of a preferential crystallographic direction). The motivation is the combination of increased piezoelectric response in certain crystallographic directions; multilayer structures where thick films rather than bulk materials can allow higher frequency operation and large area; and co-sintering to avoid detrimental effects from gluing layers together. Samples of the lead-free piezoelectric material Li0.06(K0.52Na0.48)0.94Nb0.71Ta0.29O3 with 0.25 mol% Mn (KNNLTM) were made by tape casting and co-sintering. NaNbO3 platelets with (100) orientation which were used as templates to introduce texture, and polymethyl methacrylate (PMMA) was used as a pore forming agent for making porous substrates. The electrical impedances of the co-sintered samples were recorded and analyzed by equivalent electrical circuit modelling. A texture up to 85% in the [100] crystallographic direction was obtained. The samples displayed ferro- and piezoelectricity, with a maximum thickness coupling coefficient (kt = 0.18) between mechanical and electrical energy in the most textured sample. This demonstrates that the introduction of texture in multilayered, co-sintered piezoelectrics shows promise for improving devices for ultrasound imaging or energy harvesting.
CpGtools: a python package for DNA methylation analysis
Authors: Wei Ting , Nie Jinfu , Larson Nicholas B , Ye Zhenqing , Eckel-Passow Jeanette E , Robertson Keith D , Kocher Jean-Pierre A , Wang Liguo
Published: December 2019

Motivation

DNA methylation can be measured at the single CpG level using sodium bisulfite conversion of genomic DNA followed by sequencing or array hybridization. Many analytic tools have been developed, yet there is still a high demand for a comprehensive and multifaceted tool suite to analyze, annotate, QC and visualize the DNA methylation data.

Results

We developed the CpGtools package to analyze DNA methylation data generated from bisulfite sequencing or Illumina methylation arrays. The CpGtools package consists of three types of modules: (i) ‘CpG position modules’ focus on analyzing the genomic positions of CpGs, including associating other genomic and epigenomic features to a given list of CpGs and generating the DNA motif logo enriched in the genomic contexts of a given list of CpGs; (ii) ‘CpG signal modules’ are designed to analyze DNA methylation values, such as performing the PCA or t-SNE analyses, using Bayesian Gaussian mixture modeling to classify CpG sites into fully methylated, partially methylated and unmethylated groups, profiling the average DNA methylation level over user-specified genomics regions and generating the bean/violin plots and (iii) ‘differential CpG analysis modules’ focus on identifying differentially methylated CpGs between groups using different statistical methods including Fisher’s Exact Test, Student’s t-test, ANOVA, non-parametric tests, linear regression, logistic regression, beta-binomial regression and Bayesian estimation.

Availability and implementation

CpGtools is written in Python under the open-source GPL license. The source code and documentation are freely available at https://github.com/liguowang/cpgtools.

Supplementary information

Supplementary data are available at Bioinformatics online.
Cortical Microstructural Alterations in Mild Cognitive Impairment and Alzheimer’s Disease Dementia
Authors: Vogt Nicholas M , Hunt Jack F , Adluru Nagesh , Dean Douglas C , Johnson Sterling C , Asthana Sanjay , Yu John-Paul J , Alexander Andrew L , Bendlin Barbara B
Published: December 2019

In Alzheimer’s disease (AD), neurodegenerative processes are ongoing for years prior to the time that cortical atrophy can be reliably detected using conventional neuroimaging techniques. Recent advances in diffusion-weighted imaging have provided new techniques to study neural microstructure, which may provide additional information regarding neurodegeneration. In this study, we used neurite orientation dispersion and density imaging (NODDI), a multi-compartment diffusion model, in order to investigate cortical microstructure along the clinical continuum of mild cognitive impairment (MCI) and AD dementia. Using gray matter-based spatial statistics (GBSS), we demonstrated that neurite density index (NDI) was significantly lower throughout temporal and parietal cortical regions in MCI, while both NDI and orientation dispersion index (ODI) were lower throughout parietal, temporal, and frontal regions in AD dementia. In follow-up ROI analyses comparing microstructure and cortical thickness (derived from T1-weighted MRI) within the same brain regions, differences in NODDI metrics remained, even after controlling for cortical thickness. Moreover, for participants with MCI, gray matter NDI—but not cortical thickness—was lower in temporal, parietal, and posterior cingulate regions. Taken together, our results highlight the utility of NODDI metrics in detecting cortical microstructural degeneration that occurs prior to measurable macrostructural changes and overt clinical dementia.
Association between post-percutaneous coronary intervention bivalirudin infusion and net adverse clinical events: a post hoc analysis of the GLOBAL LEADERS study
Authors: Chang Chun Chin , Chichareon Ply , Modolo Rodrigo , Takahashi Kuniaki , Kogame Norihiro , Tomaniak Mariusz , Gao Chao , Royaards Kees-Jan , Cequier Angel , Oldroyd Keith , Steg Philippe Gabriel , Hamm Christian , Jüni Peter , Valgimigli Marco , Windecker Stephan , Onuma Yoshinobu , Stables Rod H , Jan van Geuns Robert , Serruys Patrick W
Published: December 2019

Aims

The efficacy and safety of continued bivalirudin infusion after percutaneous coronary intervention (PCI) remains uncertain. We sought to investigate the association between post-PCI bivalirudin infusion and the risk of net adverse clinical events (NACE) at 30 days.

Methods and results

In the GLOBAL LEADERS study, all patients who received bivalirudin during PCI were categorized according to the use of bivalirudin infusion after the procedure. The primary endpoint of the present analysis was NACE [a composite of all-cause death, any stroke, any myocardial infarction, all revascularization, and bleeding assessed according to the Bleeding Academic Research Consortium (BARC) criteria Type 3 or 5] at 30 days. The key safety endpoint was BARC Type 3 or 5 bleeding and definite stent thrombosis. Of 15 968 patients, 13 870 underwent PCI with the use of bivalirudin. In total, 7148 patients received continued bivalirudin infusion after procedure, while 6722 patients received standard care. After propensity score covariate adjustment, the risk of NACE did not significantly differ between two treatments after PCI [continued bivalirudin infusion vs. no bivalirudin infusion: 3.2% vs. 3.1%, adjusted hazard ratio (aHR) 1.35, 95% confidence interval (CI) 0.99–1.84, P = 0.06] nor the BARC Type 3 or 5 bleeding (0.7% vs. 0.7%, aHR 0.89, 95% CI 0.44–1.79; P = 0.743) and definite stent thrombosis (0.5% vs. 0.3%, aHR 1.71, 95% CI 0.77–3.81, P = 0.189). However, continued bivalirudin infusion was associated with an increased risk of NACE and definite stent thrombosis in ST-elevation myocardial infarction (STEMI) patients.

Conclusion

In an all-comers population undergoing PCI, there was no significant difference in the risk of NACE at 30 days between continued bivalirudin infusion vs. no bivalirudin infusion after procedure but continued bivalirudin infusion was associated with a higher risk of NACE in STEMI patients when compared with no infusion.
Fractional flow reserve in clinical practice: from wire-based invasive measurement to image-based computation
Authors: Tu Shengxian , Westra Jelmer , Adjedj Julien , Ding Daixin , Liang Fuyou , Xu Bo , Holm Niels Ramsing , Reiber Johan H C , Wijns William
Published: December 2019

Fractional flow reserve (FFR) and instantaneous wave-free ratio are the present standard diagnostic methods for invasive assessment of the functional significance of epicardial coronary stenosis. Despite the overall trend towards more physiology-guided revascularization, there remains a gap between guideline recommendations and the clinical adoption of functional evaluation of stenosis severity. A number of image-based approaches have been proposed to compute FFR without the use of pressure wire and induced hyperaemia. In order to better understand these emerging technologies, we sought to highlight the principles, diagnostic performance, clinical applications, practical aspects, and current challenges of computational physiology in the catheterization laboratory. Computational FFR has the potential to expand and facilitate the use of physiology for diagnosis, procedural guidance, and evaluation of therapies, with anticipated impact on resource utilization and patient outcomes.
Functional capabilities of bacterial biofilms on gold particles
Authors: Reith Frank , Falconer Donna M , Van Nostrand Joy , Craw David , Shuster Jeremiah , Wakelin Steven
Published: December 2019

Gold particles contain gold and other toxic, heavy metals, making them ‘extreme’ geochemical microenvironments. To date, the functional capabilities of bacterial biofilms to deal with these conditions have been inferred from taxonomic analyses. The aims of this study are to evaluate the functional capabilities of bacterial communities on gold particles from six key locations using GeoChip 5.0 and to link functional and taxonomic data. Biofilm communities displayed a wide range of functional capabilities, with up to 53 505 gene probes detected. The capability of bacterial communities to (re)cycle carbon, nitrogen, and sulphur were detected. The cycling of major nutrients is important for maintaining the biofilm community as well as enabling the biogeochemical cycling and mobilisation of heavy and noble metals. Additionally, a multitude of stress- and heavy metal resistance capabilities were also detected, most notably from the α/β/γ-Proteobacteria and Actinobacteria. The multi-copper-oxidase gene copA, which is directly involved in gold resistance and biomineralisation, was the 15th most intense response and was detected in 246 genera. The Parker Road and Belle Brooke sites were consistently the most different from other sites, which may be a result of local physicochemical conditions (extreme nutrient poverty and sulphur-richness, respectively). In conclusion, biofilms on gold particles display wide-ranging metabolic and stress-related capabilities, which may enable them to survive in these niche environments and drive biotransformation of gold particles.
Maternal Differential Treatment and Psychological Well-Being: The Mediating Role of Marital Tension and Sibling Tension?
Authors: Peng Siyun , Suitor J Jill , Gilligan Megan
Published: December 2019

Objectives

Past research used equity theory and social comparison theory to explain the direct effect of maternal differential treatment (MDT) on psychological well-being. However, this focus on psychological pathways ignores possible social pathways, such as indirect effects of MDT on well-being through disrupting other family relationships. This study uses stress proliferation theory to argue that MDT, as a primary stressor in mother–child relationships, can produce secondary stressors in other family relationships (e.g., sibling tension and marital tension), which in turn leads to lower psychological well-being.

Methods

To investigate this mechanism, we conducted multilevel mediation analysis using data collected from 720 adult children nested within 308 families, as part of the Within-Family Differences Study.

Results

We found that sibling tension mediates the association between adult children’s perceptions of maternal disfavoritism and their psychological well-being—a process we call the stress proliferation of maternal disfavoritism. In contrast, adult children’s perceptions of maternal favoritism cannot trigger this stress proliferation process of producing marital tension nor sibling tension.

Discussion

The evaluation of the stress proliferation process of maternal favoritism and disfavoritism can help us to understand the difference in effects across various dimensions of MDT. This study contributes to the literature on social relationships as social determinants of health by investigating how intergenerational relationships are connected to other family relationships to affect family members’ health.
Type 2 diabetes mellitus in women with polycystic ovary syndrome during a 24-year period: importance of obesity and abdominal fat distribution
Authors: Forslund M , Landin-Wilhelmsen K , Trimpou P , Schmidt J , Brännström M , Dahlgren E
Published: December 2019

STUDY QUESTION

What are the predictive factors for later development of type 2 diabetes (T2DM) in women with polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

Obesity and abdominal fat distribution in women with PCOS in the mid-fertile years were the major risk factors for T2DM development 24 years later when lifestyle factors were similar to controls.

WHAT IS KNOWN ALREADY

Women with PCOS have an increased prevalence of T2DM.

STUDY DESIGN, SIZE, DURATION

A longitudinal and cross-sectional study was performed. Women with PCOS were examined in 1992 and in 2016. Randomly selected, age-matched women from the general population served as controls.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women with PCOS (n = 27), attending an outpatient clinical at a tertiary care centre for infertility or hirsutism were diagnosed in 1992 (mean age 30 years) and re-examined in 2016 (mean age 52 years). Women from the World Health Organization MONItoring of trends and determinants for CArdiovascular disease (WHO MONICA-GOT) 2008, aged 38–68 years, served as controls (n = 94), and they were previously examined in 1995. At both at baseline and at follow-up, women had blood samples taken, underwent a clinical examination and completed structured questionnaires, and the women with PCOS also underwent a glucose clamp test at baseline.

MAIN RESULTS AND THE ROLE OF CHANCE

None of women with PCOS had T2DM at baseline. At the 24-year follow-up, 19% of women with PCOS had T2DM versus 1% of controls (P < 0.01). All women with PCOS who developed T2DM were obese and had waist-hip ratio (WHR) >0.85 at baseline. No difference was seen between women with PCOS and controls regarding use of high-fat diet, Mediterranean diet or amount of physical activity at follow-up at peri/postmenopausal age. However, women with PCOS had a lower usage of a high-sugar diet as compared to controls (P = 0.01). The mean increases in BMI and WHR per year were similar in women with PCOS and controls during the follow-up period.

LIMITATIONS, REASONS FOR CAUTION

The small sample size of women with PCOS and the fact that they were recruited due to infertility or hirsutism make generalization to women with milder forms of PCOS uncertain.

WIDER IMPLICATIONS OF THE FINDINGS

Obesity and abdominal fat distribution, but not hyperandrogenism per se, in women with PCOS in the mid-fertile years were the major risk factors for T2DM development 24 years later when peri/postmenopausal. Lifestyle factors were similar to controls at that time.

STUDY FUNDING/COMPETING INTEREST(S)

The study was financed by grants from the Swedish state under the agreement between the Swedish government and the country councils, the ALF-agreement (ALFGBG-718611), the Gothenburg Medical Association GLS 694291 and 780821, the Swedish Heart Lung Foundation and Hjalmar Svensson Foundation. The authors have no conflict of interest.
Control of bounded solutions for first-order singular differential equations with impulses
Authors: Kong Fanchao , Nieto Juan J
Published: December 2019

This paper is concerned with a kind of first-order singular differential system with impulses. Based on the Schaefer fixed-point theorem, some new verifiable algebraic criteria are given to ensure the controllability of bounded solutions for the considered system. The results obtained in this paper not only achieve the controllability of the singular differential system with impulses for the first time, but also complement the previous researches on singular differential system with impulses. Consequently, the results established are essentially new. Finally, the effectiveness of the obtained results are illustrated via a numerical example.
Poisson–Voronoi Tessellation on a Riemannian Manifold
Authors: Calka Pierre , Chapron Aurélie , Enriquez Nathanaël
Published: December 2019

In this paper, we consider a Riemannian manifold $M$ and the Poisson–Voronoi tessellation generated by the union of a fixed point $x_0$ and a Poisson point process of intensity $\lambda $ on $M$. We obtain a two-term asymptotic expansion, when $\lambda $ goes to infinity, of the mean number of vertices of the Voronoi cell associated with $x_0$. The 1st term of the estimate is equal to the mean number of vertices in the Euclidean setting, while the 2nd term involves the scalar curvature of $M$ at $x_0$. This settles with the proper and rigorous frame the former 2D statement from [ 19] and extends it to higher dimension. The key tool for proving this result is a new change of variables formula of Blaschke–Petkantschin type in the Riemannian setting, which brings out the Ricci curvatures of the manifold.
Duration and Density of Fecal Rotavirus Shedding in Vaccinated Malawian Children With Rotavirus Gastroenteritis
Authors: Bennett Aisleen , Pollock Louisa , Jere Khuzwayo C , Pitzer Virginia E , Lopman Benjamin , Bar-Zeev Naor , Iturriza-Gomara Miren , Cunliffe Nigel A
Published: December 2019

Quantifying rotavirus shedding among vaccinated individuals will aid understanding of vaccine indirect effects. Serial stool samples were collected from 196 children who presented with rotavirus gastroenteritis to health facilities in Blantyre, Malawi, and were tested for rotavirus using a VP6 semi-quantitative, real-time polymerase chain reaction. The median duration of fecal shedding was 28 days (95% CI, 19–28). The median copy numbers for peak shedding were 1.99 × 107 (interquartile range, 3.39 × 106 to 6.37 × 107). The fecal viral load was positively associated with disease severity and negatively associated with serum anti-rotavirus immunoglobin A. High and persistent rotavirus shedding among vaccinated children with breakthrough disease may contribute to ongoing transmission in this setting.
GPC-1, a novel class A carbapenemase detected in a clinical Pseudomonas aeruginosa isolate
Authors: Schauer Jennifer , Gatermann Sören G , Hoffmann Daniel , Hupfeld Lars , Pfennigwerth Niels
Published: December 2019

Objectives

To investigate the carbapenem resistance mechanism of a carbapenem-resistant clinical Pseudomonas aeruginosa isolate.

Methods

A carbapenem-resistant P. aeruginosa isolate was recovered from a tracheal swab from a patient of a general ward in central Germany. Various phenotypic tests confirmed production of a carbapenemase that could not be identified further by PCR. A novel bla gene was identified by WGS and its carbapenemase activity was verified by heterologous expression in an Escherichia coli cloning strain. Kinetic parameters of the novel β-lactamase were determined by spectrophotometric measurements using purified enzyme.

Results

WGS confirmed the presence of a novel class A carbapenemase. The novel bla gene was named GPC-1 (GPC standing for German Pseudomonas Carbapenemase) and exhibited 77% amino acid identity to BKC-1. WGS also showed that blaGPC-1 was located on the chromosome surrounded by multiple ISs as part of a 26 kb genetic island. Heterologous expression of GPC-1 in E. coli TOP10 led to increased MICs of penicillins, oxyimino-cephalosporins, aztreonam and imipenem, but not of meropenem or ertapenem. Spectrophotometric measurements supported the MIC studies, but detected a slight hydrolysis of ertapenem and meropenem when using high concentrations of purified enzyme.

Conclusions

The biochemical characterization of GPC-1 emphasizes the ongoing emergence of novel carbapenemases. Strains expressing a weak carbapenemase like GPC-1 might go unrecognized by routine diagnostics due to low MICs for the bacterial strains producing such enzymes.
Leaf status and environmental signals jointly regulate proline metabolism in winter oilseed rape
Authors: Dellero Younes , Clouet Vanessa , Marnet Nathalie , Pellizzaro Anthoni , Dechaumet Sylvain , Niogret Marie-Françoise , Bouchereau Alain
Published: December 2019

Proline metabolism is an essential component of plant adaptation to multiple environmental stress conditions that is also known to participate in specific developmental phases, particularly in reproductive organs. Recent evidence suggested a possible role for proline catabolism in Brassica napus for nitrogen remobilization processes from source leaves at the vegetative stage. Here, we investigate transcript levels of Δ1-PYRROLINE-5-CARBOXYLATE SYNTHASE (P5CS) and PROLINE DEHYDROGENASE (ProDH) genes at the vegetative stage with respect to net proline biosynthesis and degradation fluxes in leaves having a different sink/source balance. We showed that the underexpression of three P5CS1 genes in source leaves was accompanied by a reduced commitment of de novo assimilated 15N towards proline biosynthesis and an overall depletion of free proline content. We found that the expression of ProDH genes was strongly induced by carbon starvation conditions (dark-induced senescence) compared with early senescing leaves. Our results suggested a role for proline catabolism in B. napus, but acting only at a late stage of senescence. In addition, we also identified some P5CS and ProDH genes that were differentially expressed during multiple processes (leaf status, dark to light transition, and stress response).
Cosmic evolution of star-forming galaxies to z ≃ 1.8 in the faint low-frequency radio source population
Authors: Ocran E F , Taylor A R , Vaccari M , Ishwara-Chandra C H , Prandoni I , Prescott M , Mancuso C
Published: December 2019

We study the properties of star-forming galaxies selected at 610 MHz with the GMRT in a survey covering ∼1.86 deg2 down to a noise of ∼7.1 μJy beam−1. These were identified by combining multiple classification diagnostics: optical, X-ray, infrared, and radio data. Of the 1685 SFGs from the GMRT sample, 496 have spectroscopic redshifts whereas 1189 have photometric redshifts. We find that the IRRC of star-forming galaxies, quantified by the infrared-to-1.4 GHz radio luminosity ratio $\rm {\mathit{ q}_{IR}}$, decreases with increasing redshift: $\rm {\mathit{ q}_{IR}\, =\, 2.86\pm 0.04(1\, +\, \mathit{ z})^{-0.20\pm 0.02}}$ out to z ∼ 1.8. We use the $\rm {\mathit{ V}/\mathit{ V}_{max}}$ statistic to quantify the evolution of the comoving space density of the SFG sample. Averaged over luminosity our results indicate $\rm {\langle \mathit{ V}/\mathit{ V}_{max} \rangle }$ to be $\rm {0.51\, \pm \, 0.06}$, which is consistent with no evolution in overall space density. However, we find $\rm \mathit{ V}/\mathit{ V}_{max}$ to be a function of radio luminosity, indicating strong luminosity evolution with redshift. We explore the evolution of the SFGs radio luminosity function by separating the source into five redshift bins and comparing to theoretical model predictions. We find a strong redshift trend that can be fitted with a pure luminosity evolution of the form $\rm {\mathit{ L}_{610\, MHz}\, \propto \, (\, 1+\, \mathit{ z})^{(2.95\pm 0.19)-(0.50\pm 0.15)z}}$. We calculate the cosmic SFR density since $\rm {\mathit{ z} \sim 1.5}$ by integrating the parametric fits of the evolved 610 MHz luminosity function. Our sample reproduces the expected steep decline in the star formation rate density since $\rm {\mathit{ z}\, \sim \, 1}$.
Non-thermal emission in lobes of radio galaxies – III. 3C 98, Pictor A, DA 240, Cygnus A, 3C 326, and 3C 236
Authors: Persic Massimo , Rephaeli Yoel
Published: December 2019

Recent analyses of the broad spectral energy distributions (SEDs) of extensive lobes of local radio galaxies have confirmed the leptonic origin of their Fermi/Large Area Telescope γ-ray emission, significantly constraining the level of hadronic contribution. SEDs of distant (DL > 125 Mpc) radio-galaxy lobes are currently limited to the radio and X-ray bands, hence give no information on the presence of non-thermal (NT) protons but are adequate to describe the properties of NT electrons. Modelling lobe radio and X-ray emission in 3C 98, Pictor A, DA 240, Cygnus A, 3C 326, and 3C 236, we fully determine the properties of intralobe NT electrons and estimate the level of the related γ-ray emission from Compton scattering of the electrons off the superposed cosmic microwave background, extragalactic background light, and source-specific radiation fields.
The correlations between optical/UV broad lines and X-ray emission for a large sample of quasars
Authors: Timlin John D , Brandt W N , Ni Q , Luo B , Pu Xingting , Schneider D P , Vivek M , Yi W
Published: December 2019

We present Chandra observations of 2106 radio-quiet quasars in the redshift range 1.7 ≤ z ≤ 2.7 from the Sloan Digital Sky Survey (SDSS), through data release 14 (DR14), that do not contain broad absorption lines in their rest-frame ultraviolet (UV) spectra. This sample adds over a decade worth of SDSS and Chandra observations to our previously published sample of 139 quasars from SDSS DR5 that is still used to correlate X-ray and optical/UV emission in typical quasars. We fit the SDSS spectra for 753 of the quasars in our sample that have high-quality (exposure time ≥ 10 ks and off-axis observation angle ≤ 10 arcmin) X-ray observations, and analyse their X-ray-to-optical spectral energy distribution properties (αox and  Δαox) with respect to the measured C iv and Mg ii emission-line rest-frame equivalent width (EW) and the C iv emission-line blueshift. We find significant correlations (at the ≥99.99 per cent level) between  αox and these emission-line parameters, as well as between  Δαox and  $\rm{C \, \small{IV}}$ EW. Slight correlations are found between  Δαox and  $\rm{C \, \small{IV}}$ blueshift, $\rm{Mg \, \small{II}}$ EW, and the  $\rm{C \, \small{IV}}$ EW to $\rm{Mg \, \small{II}}$ EW ratio. The best-fitting trend in each parameter space is used to compare the X-ray weakness (Δαox) and optical/UV emission properties of typical quasars and weak-line quasars (WLQs). The WLQs typically exhibit weaker X-ray emission than predicted by the typical quasar relationships. The best-fitting relationships for our typical quasars are consistent with predictions from the disc–wind quasar model. The behaviour of the WLQs compared to our typical quasars can be explained by an X-ray ‘shielding’ model.
Testing exoplanet evaporation with multitransiting systems
Authors: Owen James E , Campos Estrada Beatriz
Published: December 2019

The photoevaporation model is one of the leading explanations for the evolution of small, close-in planets and the origin of the radius-valley. However, without planet mass measurements, it is challenging to test the photoevaporation scenario. Even if masses are available for individual planets, the host star’s unknown EUV/X-ray history makes it difficult to assess the role of photoevaporation. We show that systems with multiple transiting planets are the best in which to rigorously test the photoevaporation model. By scaling one planet to another in a multitransiting system, the host star’s uncertain EUV/X-ray history can be negated. By focusing on systems that contain planets that straddle the radius-valley, one can estimate the minimum masses of planets above the radius-valley (and thus are assumed to have retained a voluminous hydrogen/helium envelope). This minimum mass is estimated by assuming that the planet below the radius-valley entirely lost its initial hydrogen/helium envelope, then calculating how massive any planet above the valley needs to be to retain its envelope. We apply this method to 104 planets above the radius gap in 73 systems for which precise enough radii measurements are available. We find excellent agreement with the photoevaporation model. Only two planets (Kepler-100c and 142c) appear to be inconsistent, suggesting they had a different formation history or followed a different evolutionary pathway to the bulk of the population. Our method can be used to identify TESS systems that warrant radial-velocity follow-up to further test the photoevaporation model.

The software to estimate minimum planet masses is publicly available at https://github.com/jo276/EvapMass.
Testing the accuracy of halo occupation distribution modelling using hydrodynamic simulations
Authors: Beltz-Mohrmann Gillian D , Berlind Andreas A , Szewciw Adam O
Published: December 2019

Halo models provide a simple and computationally inexpensive way to investigate the connection between galaxies and their dark matter haloes. However, these models rely on the assumption that the role of baryons can easily be parametrized in the modelling procedure. We aim to examine the ability of halo occupation distribution (HOD) modelling to reproduce the galaxy clustering found in two different hydrodynamic simulations, Illustris and EAGLE. For each simulation, we measure several galaxy clustering statistics on two different luminosity threshold samples. We then apply a simple five parameter HOD, which was fit to each simulation separately, to the corresponding dark matter-only simulations, and measure the same clustering statistics. We find that the halo mass function is shifted to lower masses in the hydrodynamic simulations, resulting in a galaxy number density that is too high when an HOD is applied to the dark matter-only simulation. However, the exact way in which baryons alter the mass function is remarkably different in the two simulations. After applying a correction to the halo mass function in each simulation, the HOD is able to accurately reproduce all clustering statistics for the high luminosity sample of galaxies. For the low luminosity sample, we find evidence that in addition to correcting the halo mass function, including spatial, velocity, and assembly bias parameters in the HOD is necessary to accurately reproduce clustering statistics.
Host Inflammatory Biomarkers of Disease Severity in Pediatric Community-Acquired Pneumonia: A Systematic Review and Meta-analysis
Authors: Fernandes Catarina D , Arriaga María B , Costa Maria Carolina M , Costa Maria Clara M , Costa Maria Heloina M , Vinhaes Caian L , Silveira-Mattos Paulo S , Fukutani Kiyoshi F , Andrade Bruno B
Published: December 2019

Background

Community-acquired pneumonia (CAP) is the leading cause of death in children. Identification of reliable biomarkers offers the potential to develop a severity quantitative score to assist in clinical decision-making and improve outcomes.

Methods

A systematic review and meta-analysis was performed in PubMed and EMBASE on November 13, 2018, to examine the association between host inflammatory biomarkers and CAP severity in children. The inclusion criteria were case–control, cross-sectional, and cohort studies that examined candidate serum biomarkers. We extracted outcomes of interest, means, and standardized mean differences (SMDs) of plasma and serum levels of biomarkers together with information on disease severity. Meta-analysis was performed. This review was registered in the PROSPERO international registry (CRD42019123351).

Results

Two hundred seventy-two abstracts were identified, and 17 studies were included. Among the biomarkers evaluated, levels of C-reactive protein (CRP; SMD, 0.63; 95% confidence interval [CI], 0.35 to 0.91), interleukin (IL)-6 (SMD, 0.46; 95% CI, 0.25 to 0.66), IL-8 (SMD, 0.72; 95% CI, 0.15 to 1.29), neutrophil count (SMD, 0.27; 95% CI, 0.07 to 0.47), and procalcitonin (SMD, 0.68; 95% CI, 0.20 to 1.15) were substantially increased in severe CAP. In contrast, IL-2 concentrations (SMD, –0.24; 95% CI, –0.45 to –0.03) were higher in nonsevere CAP. Study heterogeneity was reported to be high (I2 > 75%), except for IL-2, IL-5, IL-6, and IL-12p70, which were classified as moderate (I2 = 50%–74%). Only neutrophil and white blood cell counts were described by studies exhibiting a low level of heterogeneity.

Conclusions

Our results suggest that host biomarkers, and especially CRP, IL-6, IL-8, and procalcitonin levels, have the potential to predict severe CAP in pediatric populations.
Application of nuclear magnetic resonance for analyzing metabolic characteristics of winter diatom blooms
Authors: Jeong Kwang-Seuk , Jeong Keon-Young , Hong Young-ShiCk , Kim Dong-Kyun , Oh Hye-Ji , Chang Kwang-Hyeon
Published: December 2019

We compared two metabolome profiles of a small centric diatom species, Stephanodiscus hantzschii Grun., grown under conditions with enriched nutrients but different temperatures. This species proliferates in eutrophic rivers during winter. We investigated the population dynamics and internal metabolite changes of Stephanodiscus by performing a simple culture experiment at different temperatures (5 and 15°C). We applied the 1H nuclear magnetic resonance (NMR) technique to fully grown cells to obtain the metabolite profiles of S. hantzschii. Growth rates were significantly different at different temperature conditions (0.99 ± 0.11 day−1 at 15°C and 0.21 ± 0.12 day−1 at 5°C, n = 10). Characterized metabolites included saturated and unsaturated fatty acids, AXP (including AMP, ADP and ATP), and UDP-glucose and UDP-galactose, all of which are important for energy metabolism. These metabolites were abundant within S. hantzschii cells grown at 15°C but were not prolific in those grown at 5°C. Furthermore, other 1H NMR spectrum uncovered very little amounts of metabolites. Based on these observations of cell growth rate, although required nutrients were supplied, colder temperatures suppressed population growth through the deactivation of various internal metabolisms. Thus, winter proliferation of this species is opportunistic, implying that survival success led to dominance in freshwater ecosystems with neither resource competition nor grazing pressure.
Light exposure decreases infectivity of the Daphnia parasite Pasteuria ramosa
Authors: Overholt Erin P , Duffy Meghan A , Meeks Matthew P , Leach Taylor H , Williamson Craig E
Published: December 2019

Climate change is altering light regimes in lakes, which should impact disease outbreaks, since sunlight can harm aquatic pathogens. However, some bacterial endospores are resistant to damage from light, even surviving exposure to UV-C. We examined the sensitivity of Pasteuria ramosa endospores, an aquatic parasite infecting Daphnia zooplankton, to biologically relevant wavelengths of light. Laboratory exposure to increasing intensities of UV-B, UV-A, and visible light significantly decreased P. ramosa infectivity, though there was no effect of spore exposure on parasitic castration of infected hosts. P. ramosa is more sensitive than its Daphnia host to damage by longer wavelength UV-A and visible light; this may enable Daphnia to seek an optimal light environment in the water column, where both UV-B damage and parasitism are minimal. Studies of pathogen light sensitivity help us to uncover factors controlling epidemics in lakes, which is especially important given that water transparency is decreasing in many lakes.
The N-terminal 1–55 residues domain of pyruvate dehydrogenase from Escherichia coli assembles as a dimer in solution
Authors: Wang Yuanyuan , Gong Zemao , Fang Han , Zhi Dongming , Tao Hu
Published: December 2019

The pyruvate dehydrogenase complex (PDHc) from Escherichia coli is a large protein complex consisting of multiple copies of the pyruvate dehydrogenase (E1ec), dihydrolipoamide acetyltransferase (E2ec) and dihydrolipoamide dehydrogenase (E3ec). The N-terminal domain (NTD, residues 1–55) of E1ec plays a critical role in the interaction between E1ec and E2ec and the whole PDHc activity. Using circular dichroism, size-exclusion chromatography and dynamic light scattering spectroscopy, we show that the NTD of E1ec presents dimeric assembly under physiological condition. Pull-down and isothermal titration calorimetry binding assays revealed that the E2ec peripheral subunit-binding domain (PSBD) forms a very stable complex with the NTD, indicating the isolated NTD functionally interacts with PSBD and the truncated E1ec (E1ec∆NTD) does not interact with PSBD. These findings are important to understand the mechanism of PDHc and other thiamine-based multi-component enzymes.
The altered early components and the decisive later process underlying attention bias modification in social anxiety: evidence from event-related potentials
Authors: Pan Dong-ni , Wang Yi , Lei Zheng , Wang Yang , Li Xuebing
Published: December 2019

Attention bias modification (ABM) is a potential intervention in relieving social anxiety symptoms, while its underlying neural mechanisms are not yet understood. The current study included 63 college students with social anxiety. Participants were assigned to the attention modification program (AMP, n = 20), the attention control condition (ACC, n = 20) and the passive waiting group (PW, n = 23). Questionnaires and the emotional Stroop task with EEG recordings were used to assess whether and how the 4-week ABM period affected emotional symptoms and specific emotional processing. Results showed that the two training groups (AMP and ACC) produced comparable emotional improvements and both showed a decrease in negative bias compared with the PW group. The ERP results indicated that despite no significant ERP changes in the PW group, the ACC group exhibited a greater N1, whereas the AMP group exhibited a reduced VPP at the post-test stage compared to the pre-test stage. Besides, both training groups showed a similar late positive potential (LPP) reduction. Notably, the reduction in LPP was positively correlated with behavioral and symptom improvement. Thus, manipulations unique to ABM (face-target contingency) primarily modulate the early attention distribution of material-related stimuli. However, the clinical benefits of attention training may be due to later cognitive-affective mechanisms.
Effect of stage of maturity at harvest for forage pea (Pisum sativum L.) on eating behavior, ruminal fermentation, and digestibility when fed as hay to yearling beef heifers
Authors: Pursley Alex A , Biligetu Bill , Warkentin Tom , Lardner Herbert A , Penner Gregory B
Published: December 2019

The objective of this study was to evaluate the stage of maturity at harvest for pea hay (Pisum sativum L., c.v. CDC Horizon) on dry matter intake (DMI), eating behavior, ruminal fermentation, and digestibility when fed to beef heifers. Pea hay was cut at EARLY (defined to occur when flat pods were on one or more nodes), MID (when seeds filled the pods at one or more nodes and the leaves were changing from green to gold), and LATE (yellow dry seeds filled pods on most or all of the nodes and the pods and leaves had a yellow color) phases, and was cured in the field and baled. Six ruminally-cannulated Speckle Park heifers were used in a replicated 3 × 3 Latin square design with three 18-d periods including 12 d for adaptation, 2 d for measurement of ruminal pool sizes, and 4 d for the collection of eating behavior, ruminal pH, ruminal digesta, and feces. For all treatments, the respective pea hay was included at 40% of the dietary DM. Stage of maturity at harvest for pea hay did not affect total DMI, pea hay DMI, or the total short-chain fatty acid concentration in ruminal fluid with averages of 8.6 kg/d, 3.2 kg/d, and 96.55 mM, respectively. The duration of time spent ruminating decreased with advancing pea hay maturity when reported as min/d, min/kg DMI, and min/kg neutral detergent fiber (NDF) (P ≤ 0.01). Mean ruminal pH also decreased with advancing pea maturity (P < 0.01). The ruminal DM and undigested NDF corrected for OM pools were not affected by stage of maturity (P ≥ 0.55) nor was the rate of digestion for NDF. However, NDF passage rate decreased by 0.21%/h with advancing pea hay maturity (P = 0.02). Apparent total tract digestibility of NDF (average = 16.30%, P = 0.41) was not affected, but starch digestibility decreased from 96.10% to 93.08% with advancing pea hay maturity (P = 0.07). Overall, stage of maturity at harvest for pea hay does not appear to affect DMI or NDF digestibililty but decreases chewing activity, apparent total tract starch digestibility, ruminal pH, and ruminal NDF passage rate.