bluuebunny/crossref_metadata_2025 huggingface dataset:
Precise distances to red giant stars with seismic data using the near-IR surface-brightness relation
Authors: Storm Jesper , Graczyk Dariusz , Valentini Marica , Anders Friedrich , Chiappini Cristina , Gieren Wolfgang , Pietrzynski Grzegorz
Published: August 2018

The Kepler and CoRoT satellites have determined precise asteroseismic radii for large samples of red giant stars. Combining these data with data from spectroscopic and photometric surveys has led to precise distance determinations using comprehensive Bayesian methods. Here we determine angular diameters and thus distances using the interferometrically calibrated near-IR surface-brightness method finding good agreement with previous results. The method can easily be reversed when accurate Gaia parallaxes for these stars become available to calibrate the asteroseismic scaling relations.
How does the stellar disk of the Milky Way get its gas?
Authors: Nuza Sebastián E. , Chiappini Cristina , Scannapieco Cecilia , Minchev Ivan , Martig Marie , Junqueira Thiago C.
Published: August 2018

In chemodynamical evolution models it is usually assumed that the Milky Way galaxy forms from the inside-out implying that gas inflows onto the disk decrease with galactocentric distance. Similarly, to reproduce differences between chemical abundances of the thick disk and bulge with respect to those of the thin disk, higher accretion fluxes at early times are postulated. By using a suite of Milky Way-like galaxies extracted from cosmological simulations, we investigate the accretion of gas on the simulated stellar disks during their whole evolution. In general, we find that the picture outlined above holds, although the detailed behavior depends on the assembly history of the Galaxy and the complexities inherent to the physics of galaxy formation.
The DR14 APOGEE-TGAS catalogue: Precise chemo-kinematics in the extended solar vicinity
Authors: Anders Friedrich , Queiroz Anna B. , Chiappini Cristina , Santiago Basílio X. , Fernández-Trincado J. G. , Meza Andres ,   the SDSS-IV/APOGEE Collaboration
Published: August 2018

We describe the DR14 APOGEE-TGAS catalogue, a new SDSS value-added catalogue that provides precise astrophysical parameters, chemical abundances, astro-spectro- photometric distances and extinctions, as well as orbital parameters for ~30, 000 APOGEE-TGAS stars, among them ~5, 000 high-quality giant stars within 1 kpc.
Very Metal-Poor Stars and the Early Universe
Authors: Norris John E.
Published: August 2018

Very metal-poor stars ([Fe/H] < –2.0) inform our understanding of the formation and evolution of the Galaxy, and the physical conditions in the earliest star-forming environments of the Universe. They play an integral part in the paradigms of stellar populations, stellar archaeology, and near-field cosmology. We review the carbon-rich and carbon-normal sub-populations of the most iron-poor stars, providing insight into chemical enrichment at the earliest times in the Universe. We also discuss the role of very metal-poor stars in providing insight into the Galaxy’s halo, thick disk, and bulge, and the promise they hold for the future. A comparison between the abundances obtained for the nine most Fe-poor stars ([Fe/H] < –4.5) (all but one of which is C-rich) with abundances obtained from far-field cosmology suggests that the former are the most chemically primitive objects yet observed and probably older than the DLA- and sub-DLA systems for which data are currently available from far-field studies.
Combining asteroseismology and spectroscopy for obtaining precise abundances: CoRoT-GES and K2-RAVE
Authors: Valentini M. ,   CoRoT-GES and K2-RAVE collaborations
Published: August 2018

The spectroscopic analysis of red giant stars is hampered by difficulties in determining the surface gravity, log g. The presence of degeneracies, few lines sensitive to log g, limited spectral coverage and bad signal-to-noise, can affect the precision and accuracy of log g and, as a consequence, the quality of the element abundances. We show how the adoption of the seismic surface gravity can improve the spectroscopic analysis of red giants. As examples, we adopted the seismic gravity in the analysis of spectra taken by two different surveys: GES (high resolution) and RAVE (intermediate resolution). The results of this technique were the lifting of the log g-Teff degeneracy and more accurate and precise atmospheric parameters and abundances.
Massive stars: stellar models and stellar yields, impact on Galactic Archaeology
Authors: Meynet Georges , Choplin Arthur , Ekström Sylvia , Georgy Cyril
Published: August 2018

The physics of massive stars depends (at least) on convection, mass loss by stellar winds, rotation, magnetic fields and multiplicity. We briefly discuss the impact of the first three processes on the stellar yields trying to identify some guidelines for future works.
A miniaturized broadband monopulse comparator with all DELTA channels nulling in Ku band
Authors: Alamdar Saeid , Mohammadpour-Aghdam Karim , Khalili Hossein , Mohammad-Taheri Mahmoud
Published: August 2018

A compact monopulse comparator with complete nulling in all DELTA channels is designed and fabricated. The proposed comparator has small dimension and consists of interconnections of four broadband branch-line couplers and several 90° phase shifters with multistage Schiffman coupled-lines. This comparator has been characterized by its eight-portS-parameters to generate the SUM and DELTA channel frequency responses. Over 30-dB null depth was achieved in DELTA channels across the SUM channels in pass band from 14.8 to 18.2 GHz frequency range.
A multicentre randomized controlled trial on trans-generational attention deficit/hyperactivity disorder (ADHD) in mothers and children (AIMAC): an exploratory analysis of predictors and moderators of treatment outcome
Authors: Jaite Charlotte , van Noort Betteke Maria , Vloet Timo D. , Graf Erika , Kappel Viola , Geissler Julia , Warnke Andreas , Jacob Christian , Groß-Lesch Silke , Hennighausen Klaus , Haack-Dees Barbara , Schneider-Momm Katja , Philipsen Alexandra , Matthies Swantje , Rösler Michael , Retz Wolfgang , Hänig Susann , von Gontard Alexander , Sobanski Esther , Alm Barbara , Hohmann Sarah , Häge Alexander , Poustka Luise , Colla Michael , Gentschow Laura , Freitag Christine M. , Becker Katja , Jans Thomas
Published: August 2018

Abstract. Objective: We examined predictors and moderators of treatment outcome in mothers and children diagnosed with ADHD in a large multicentre RCT. Method: In total, 144 mother-child dyads with ADHD were randomly assigned to either a maternal ADHD treatment (group psychotherapy and open methylphenidate medication, TG) or to a control treatment (individual counselling without psycho- or pharmacotherapy, CG). After maternal ADHD treatment, parent-child training (PCT) for all mother-child dyads was added. The final analysis set was based on 123 dyads with completed primary outcome assessments (TG: n = 67, CG: n = 56). The primary outcome was the change in each child’s externalizing symptoms. Multiple linear regression analyses were performed. Results: The severity of the child’s externalizing problem behaviour in the family at baseline predicted more externalizing symptoms in the child after PCT, independent of maternal treatment. When mothers had a comorbid depression, TG children showed more externalizing symptoms after PCT than CG children of depressive mothers. No differences between the treatment arms were seen in the mothers without comorbid depression. Conclusions: Severely impaired mothers with ADHD and depressive disorder are likely to need additional disorder-specific treatment for their comorbid psychiatric disorders to effectively transfer the contents of the PCT to the home situation (CCTISRCTN73911400).
Intuitive Eating
Authors: Barrada Juan Ramón , Cativiela Blanca , van Strien Tatjana , Cebolla Ausiàs
Published: August 2018

Abstract. Intuitive eating is defined as an adaptive way of eating that maintains a strong connection with the internal physiological signs of hunger and satiety. It has four elements: unconditional permission to eat whenever and whatever food is desired, eating for physical rather than for emotional reasons, reliance on hunger and satiety cues to determine when and how much to eat, and body-food choice congruence. In this study, we assessed the differences and similarities between intuitive eating, as measured with the Intuitive Eating Scale-2 (IES-2), and eating styles (restrained, emotional, and external eating), assessed with the Dutch Eating Behavior Questionnaire (DEBQ). Using a Spanish sample of mainly university students ( n = 1,095) we found that (a) unconditional permission to eat presented a large negative correlation with restrained eating, r = –.82; (b) eating for physical reasons had a large negative correlation with emotional eating, r = –.70; (c) the dimensions of intuitive eating only showed very small correlations with positive and negative affect, satisfaction with life, body dissatisfaction or weight control behavior after restrained, emotional, and external eating had been partialled out. Altogether, the present results suggest that two of the dimensions of intuitive eating as assessed with the IES-2 are not very new or innovative. The most promising new dimension of intuitive eating seems to be body-food choice congruence.
Effects of Biological Production and Vertical Mixing on Sea Surface pCO2 Variations in the Changjiang River Plume During Early Autumn: A Buoy‐Based Time Series Study
Authors: Li Dewang , Chen Jianfang , Ni Xiaobo , Wang Kui , Zeng Dingyong , Wang Bin , Jin Haiyan , Huang Daji , Cai Wei‐Jun
Published: August 2018

A monthlong, high‐resolution buoy time series from the surface ocean of the Changjiang River plume in early autumn 2013 (30‐min sampling frequency) shows great variability in the partial pressure of carbon dioxide (pCO2) and other physical and biogeochemical parameters. Early in the deployment, surface pCO2 decreased by ~117 μatm in a single day (11–12 September, from an initial value of ~527 μatm); a similar decline of 62 μatm occurred five days later (to ~378 μatm). Both drawdown events were associated with strong vertical stratification, high chlorophyll a concentrations, and oxygen supersaturation. A one‐dimensional mass balance model suggests that biological production was responsible for more than half the pCO2 decrease observed during 10–23 September. Subsequently, in association with strong winds, the mixed layer rapidly deepened and surface pCO2 increased sharply (by about 108 μatm in late September and again in early October). Vertical mixing accounted for more than half of this pCO2 increase, which offset more than the earlier biologically driven CO2 drawdown. In the presence of such strong temporal variations of pCO2, sampling frequency exerts a substantial influence on air‐sea CO2 flux calculations for the Changjiang River plume and similar coastal areas. Compared to daily sampling, even weekly sampling would result in a bias of up to ±4.7 mmol C · m−2 · day−1 or ±63% error.
Field‐Aligned Current and Polar Cap Potential and Geomagnetic Disturbances: A Review of Cross‐Correlation Analysis
Authors: Adhikari Binod , Dahal Subodh , Sapkota Nirakar , Baruwal Prashrit , Bhattarai Binod , Khanal Krishna , Chapagain Narayan P.
Published: August 2018

Polar cap potential (PCV) is an important parameter used for determining what kind of interaction takes place between solar wind and magnetosphere. Highly energetic particles from Sun driven by solar wind constantly bombard with Earth's magnetosphere–ionosphere system that results into a phenomenon like auroras, and major geomagnetic disturbances. Solar wind electron deposition determines the magnitude of field‐aligned current (FAC) and ultimately leads to PCV variation. Several studies found that increase in magnitude of IMF‐Bz causes an electric field of cross magnetosphere to increase, and it leads to increase in magnitude of ionospheric cross‐polar cap potential (PCV). Moreover, PCV was found to be a linear function of Vsw. In this research, we aim to study how field‐aligned current (FAC), for example, region 1 current and PCV, is related during different forms of geomagnetic disturbances. In all events, FAC and PCV are found to have corresponding fluctuations—especially at times of significant variation of IMF‐Bz (negative Bz interval) following the linearity of equation suggested by Moon in Moon (2012, https://doi.org/10.5140/JASS.2012.29.3.259). We found one‐to‐one correspondence between FAC and PCV. We did CWT analysis and found that FAC and PCV have more or less same spectral behaviors for each event considered. The cross‐correlation analysis shows a high and positive correlation between FAC and PCV at 0‐min time lag for all geomagnetic activity. The CWT analysis clearly supports the result of cross correlation between FAC and PCV. We found that FAC and Vsw, FAC‐B, and FAC and AE are also positively correlated with high‐correlation coefficient at lag 0 min for all geomagnetic storm. However, FAC‐Bz, FAC‐By, and FAC‐SYM (H) have varying correlation in different events. For a particular storm and substorm, the parameters Bz and By may not necessarily be varied with FAC in regular sequence but IMF (B) always show positive correlation with FAC for all geomagnetic activity. This paper presents a clear relation between FAC and PCV. This result will help to identify some of the outstanding issues in determining the causal mechanism of PCV variation, a crucial thing to understanding the coupling between the solar wind and M‐I system.
Extending the Solidus for a Model Iron‐Rich Martian Mantle Composition to 25 GPa
Authors: Duncan Megan S. , Schmerr Nicholas C. , Bertka Constance M. , Fei Yingwei
Published: August 2018

The solidus for the mantle of Mars is an important geophysical parameter in modeling the thermal history and evolution of the planet. This study provides solidus data for a simplified model Martian mantle composition from the midmantle (8 GPa) to the core–mantle boundary (25 GPa) using multianvil experiments. Combining this work with previous studies, the solidus for the entire mantle of Mars is constrained to within 70 °C. The major mineral assemblages and phase transitions observed are consistent with those predicted for an iron‐rich Martian mantle. The solidus for the Martian composition falls above the solidus of MORB and below that of terrestrial peridotite, providing direct melting data for geophysical modeling of the Martian interior. Our solidus also predicts that a Martian mantle plume should produce melt at depths over a range of 200–350 km in the mantle.
Response of the Intertropical Convergence Zone to Antarctic Ice Sheet Melt
Authors: Bakker Pepijn , Prange Matthias
Published: August 2018

Past cooling events in the Northern Hemisphere have been shown to impact the location of the intertropical convergence zone (ITCZ) and therewith induce a southward shift of tropical precipitation. Here we use high resolution coupled ocean‐atmosphere simulations to show that reasonable past melt rates of the Antarctic Ice Sheet can similarly have led to shifts of the ITCZ, albeit in opposite direction, through large‐scale surface air temperature changes over the Southern Ocean. Through sensitivity experiments employing slightly negative to large positive meltwater fluxes, we deduce that meridional shifts of the Hadley cell and therewith the ITCZ are, to a first order, a linear response to Southern Hemisphere high‐latitude surface air temperature changes and Antarctic Ice Sheet melt rates. This highlights the possibility to use past episodes of anomalous melt rates to better constrain a possible future response of low latitude precipitation to continued global warming and a shrinking Antarctic Ice Sheet.
Comparing Eddy‐Permitting Ocean Model Parameterizations via Lagrangian Particle Statistics in a Quasigeostrophic Setting
Authors: Chen Amy , Barham William , Grooms Ian
Published: August 2018

This paper uses Lagrangian statistics—absolute dispersion, pair dispersion, and particle forecasting—to compare four eddy‐permitting models of idealized mesoscale ocean dynamics. The baseline model uses scale‐selective biharmonic damping of momentum to keep the velocity field smooth at the grid scale without overly smearing the partially resolved eddies. The second model uses a nonlinear space‐ and time‐varying Leith viscosity to absorb enstrophy near the grid scale without dissipating too much energy. The last two models use a strong biharmonic damping of momentum to keep the velocity field smooth at the grid scale; this dissipates an unrealistically large amount of kinetic energy, and the models add either deterministic or stochastic forcing to reinject this energy at larger scales. These models are called Jansen and Held models after Jansen and Held (2014, https://doi.org/10.1016/j.ocemod.2014.06.002). All four models correctly model the diffusive transport of particles over time scales more than a few weeks, as measured by the Lagrangian absolute dispersion, showing that all models correctly reproduce the large scales of coherent eddies. The Lagrangian relative dispersion (or pair dispersion) is more sensitive to structure at smaller scales in the velocity field. The Leith model has the least‐accurate relative dispersion, while the two Jansen and Held models have the most accurate. In initialized forecast experiments, there is very little difference in performance between the models.
Impacts of Land Cover and Soil Texture Uncertainty on Land Model Simulations Over the Central Tibetan Plateau
Authors: Li Jianduo , Chen Fei , Zhang Guo , Barlage Michael , Gan Yanjun , Xin Yufei , Wang Chen
Published: August 2018

Land surface processes and their coupling to the atmosphere over the Tibetan Plateau (TP) play an important role in modulating the regional and global climate. Therefore, identifying and quantifying uncertainty in these land surface model (LSM) processes are essential for improving climate models. The specifications of land cover and soil texture types, intertwined with the uncertainties in associated vegetation and soil parameters in LSMs, are significant sources of uncertainty due to the lack of detailed land survey in the TP. To differentiate the effects of land cover or soil texture specifications in the Noah with Multiple Parameterizations (Noah‐MP) LSM from the effects of uncertainties in the model parameters, this study first identified the most sensitive vegetation and soil parameters through global sensitivity analysis and then conducted parametric ensemble simulations using two land cover data sets and two soil texture data sets over the central TP to estimate their corresponding impacts on the overall model responses. The distinction level and the Kolmogorov‐Smirnov test were then applied to assess the differences between the results from parametric ensemble simulations using different land cover or soil texture data sets. The results show that the simulated energy and water fluxes over the central TP are dominated by soil parameters. The canopy height is the most sensitive vegetation parameter, and the Clapp‐Hornberger b parameter (the exponent in the function that relates soil water potential and water content) is the most sensitive soil parameter. Relative to the background parametric uncertainties, the Noah‐MP LSM could not sufficiently distinguish the effects of changes between forested types or soil texture types, which highlight the need for further quantifying and reducing the parametric uncertainties in LSMs. Further analysis shows significant sensitivities of the distinction level and changes in model response to annual precipitation and vegetation fraction. This work provides a scientific reference for assessing the impacts of land cover or soil texture changes on Noah‐MP simulations under future climate change conditions.
A hybrid invisibility cloak based on integration of transparent metasurfaces and zero-index materials
Authors: Chu Hongchen , Li Qi , Liu Bingbing , Luo Jie , Sun Shulin , Hang Zhi Hong , Zhou Lei , Lai Yun
Published: August 2018

The invisibility cloak, a long-standing fantastic dream for humans, has become more tangible with the development of metamaterials. Recently, metasurface-based invisibility cloaks have been proposed and realized with significantly reduced thickness and complexity of the cloaking shell. However, the previous scheme is based on reflection-type metasurfaces and is thus limited to reflection geometry. In this work, by integrating the wavefront tailoring functionality of transparent metasurfaces and the wave tunneling functionality of zero-index materials, we have realized a unique type of hybrid invisibility cloak that functions in transmission geometry. The principle is general and applicable to arbitrary shapes. For experimental demonstration, we constructed a rhombic double-layer cloaking shell composed of a highly transparent metasurface and a double-zero medium consisting of dielectric photonic crystals with Dirac cone dispersions. The cloaking effect is verified by both full-wave simulations and microwave experimental results. The principle also reveals exciting possibilities for realizing skin-thick ultrathin cloaking shells in transmission geometry, which can eliminate the need for spatially varying extreme parameters. Our work paves a path for novel optical and electromagnetic devices based on the integration of metasurfaces and metamaterials.
Opposing effects of final population density and stress on Escherichia coli mutation rate
Authors: Krašovec Rok , Richards Huw , Gifford Danna R , Belavkin Roman V , Channon Alastair , Aston Elizabeth , McBain Andrew J , Knight Christopher G
Published: August 2018

Evolution depends on mutations. For an individual genotype, the rate at which mutations arise is known to increase with various stressors (stress-induced mutagenesis—SIM) and decrease at high final population density (density-associated mutation-rate plasticity—DAMP). We hypothesised that these two forms of mutation-rate plasticity would have opposing effects across a nutrient gradient. Here we test this hypothesis, culturing Escherichia coli in increasingly rich media. We distinguish an increase in mutation rate with added nutrients through SIM (dependent on error-prone polymerases Pol IV and Pol V) and an opposing effect of DAMP (dependent on MutT, which removes oxidised G nucleotides). The combination of DAMP and SIM results in a mutation rate minimum at intermediate nutrient levels (which can support 7 × 108 cells ml−1). These findings demonstrate a strikingly close and nuanced relationship of ecological factors—stress and population density—with mutation, the fuel of all evolution.
Cognitive function following breast cancer treatment and associations with concurrent symptoms
Authors: Van Dyk Kathleen , Bower Julienne E. , Crespi Catherine M. , Petersen Laura , Ganz Patricia A.
Published: August 2018

Cognitive changes after breast cancer treatment are often attributed to chemotherapy, without considering other important factors such as other treatments (e.g., surgery, radiation, endocrine therapy (ET)). We compared neuropsychological functioning in the domains of learning, memory, attention, visuospatial, executive function, and processing speed according to primary breast cancer treatment exposures in early survivorship, before the initiation of ET (n = 189). We were also interested in the association of neuropsychological functioning with select clinical, psychological, and behavioral factors. Compared to those who only underwent surgery (n = 28), all neuropsychological domain scores were comparable in a sample of breast cancer survivors with different treatment exposures, i.e., radiation therapy (n = 64), chemotherapy (n = 20), or both (n = 77), p’s < 0.05, adjusted for age, IQ, depression, and time since treatment completion. Physical fatigue, pain, and sleep correlated with several cognitive domains regardless of treatment exposure. There are minimal treatment-related neuropsychological differences on neuropsychological measures in early breast cancer survivorship, but the influence of other co-occurring symptoms warrants attention.
Polyacrylamide degradation and its implications in environmental systems
Authors: Xiong Boya , Loss Rebeca Dettam , Shields Derrick , Pawlik Taylor , Hochreiter Richard , Zydney Andrew L , Kumar Manish
Published: August 2018

High molecular weight (106–3 × 107 Da) polyacrylamide (PAM) is commonly used as a flocculant in water and wastewater treatment, as a soil conditioner, and as a viscosity modifier and friction reducer in both enhanced oil recovery and high volume hydraulic fracturing. These applications of PAM can result in significant environmental challenges, both in water management and in contamination of local water supplies after accidental spills. This paper provides a short review of current applications of high molecular weight PAM, including the potential for PAM degradation by chemical, mechanical, thermal, photolytic, and biological processes. Methods for treating wastewater containing partially degraded PAM are then discussed along with issues related to the potential toxicity and mobility of PAM in the environment after disposal or accidental release.
Retention and losses of ultraviolet-sensitive visual pigments in bats
Authors: Li Longfei , Chi Hai , Liu Haonan , Xia Yu , Irwin David M. , Zhang Shuyi , Liu Yang
Published: August 2018

Ultraviolet (UV)-sensitive visual pigment and its corresponding ability for UV vision was retained in early mammals from their common ancestry with sauropsids. Subsequently, UV-sensitive pigments, encoded by the short wavelength-sensitive 1 (SWS1) opsin gene, were converted to violet sensitivity or have lost function in multiple lineages during the diversification of mammals. However, many mammalian species, including most bats, are suggested to retain a UV-sensitive pigment. Notably, some cave-dwelling fruit bats and high duty cycle echolocating bats have lost their SWS1 genes, which are proposed to be due to their roosting ecology and as a sensory trade-off between vision and echolocation, respectively. Here, we sequenced SWS1 genes from ecologically diverse bats and found that this gene is also non-functional in both common vampire bat (Desmodus rotundus) and white-winged vampire bat (Diaemus youngi). Apart from species with pesudogenes, our evolutionary and functional studies demonstrate that the SWS1 pigment of bats are UV-sensitive and well-conserved since their common ancestor, suggesting an important role across major ecological types. Given the constrained function of SWS1 pigments in these bats, why some other species, such as vampire bats, have lost this gene is even more interesting and needs further investigation.
Elicitors Derived from Hazel (Corylus avellana L.) Cell Suspension Culture Enhance Growth and Paclitaxel Production of Epicoccum nigrum
Authors: Salehi Mina , Moieni Ahmad , Safaie Naser
Published: August 2018

The microbial fermentation is considered as the potential source for large-scale production of paclitaxel. Since co-cultivation/mixed fermentation strategy has been reported as a yield enhancement strategy for paclitaxel production, investigation of fungal endophyte response to plant culture medium, plant cell extract (CE) and medium filtrate (MF) of plant cell suspension culture in terms of growth and paclitaxel production is interesting. In this study, 35 endophytic fungi were isolated from Taxus baccata and Corylus avellana grown in Iran. The analysis of high-performance liquid chromatography and mass spectrometry showed that one isolate (YEF2) produced paclitaxel. The isolate YEF2 was identified as Epicoccum nigrum by sequencing of ITS1-5.8S-ITS2 rDNA region and actin gene. YEF2 was slow-growing in Murashige and Skoog medium, but the synergistic interaction of gibberellic acid (GA3) and CE of C. avellana enhanced the growth of YEF2. The highest total yield of paclitaxel (314.7 µg/l; 11.5-folds) of E. nigrum strain YEF2 was obtained by using 28% (v/v) filter sterilized CE of C. avellana and 2 µg ml−1 GA3 that was significantly higher than the control. In this study, the effects of the plant cell extract on growth and paclitaxel production of paclitaxel producing endophytic fungus were studied for the first time.
New aspects of longitudinal instabilities in electron storage rings
Authors: Blednykh A. , Bacha B. , Bassi G. , Cheng W. , Chubar O. , Derbenev A. , Lindberg R. , Rakitin M. , Smaluk V. , Zhernenkov M. , Chen-Wiegart Yu-chen Karen , Wiegart L.
Published: August 2018

Novel features of the longitudinal instability of a single electron bunch circulating in a low-emittance electron storage ring are discussed. Measurements and numerical simulations, performed both in time and frequency domain, show a non-monotonic increase of the electron beam energy spread as a function of single bunch current, characterized by the presence of local minima and maxima, where a local minimum of the energy spread is interpreted as a higher-order microwave instability threshold. It is also shown that thresholds related to the same zero-intensity bunch length depend linearly on the accelerating radio frequency voltage. The observed intensity-dependent features of the energy spread, confirmed by measurements with two independent diagnostics methods, i.e. horizontal beam profile measurements by a synchrotron light monitor and photon energy spectrum measurements of undulator radiation, are given a theoretical interpretation by applying a novel eigenvalue analysis based on the linearized Vlasov equation.
Profile distribution of CO2 in an arid saline-alkali soil with gypsum and wheat straw amendments: a two-year incubation experiment
Authors: Wang Junyi , Wang Xiujun , Wang Jiaping
Published: August 2018

Adding gypsum and/or straw is a common practice for ameliorating saline-alkali soils. However, the effect of amendment on soil CO2 is poorly known. An incubation experiment was conducted for over two years in a saline-alkali soil of Yanqi Basin, which included four treatments: control, gypsum addition (Ca), wheat straw addition (S) and gypsum-wheat straw combination (Ca+S). We continuously monitored soil CO2 concentration, temperature and moisture at 15, 30, 45 and 60 cm. There was a clear seasonality in soil CO2 under all four treatments, which was generally similar to those in soil temperature and moisture. Straw addition led to a significant increase in soil CO2 over 0–60 cm in summer. While there was a significant increase of soil CO2 with gypsum addition only, soil CO2 significantly decreased with the addition of gypsum and straw (relative to straw addition only) during autumn and winter in 2014. Interestingly, integrated soil CO2 was lowest in soil profile under the Ca+S treatment during winter and spring. Our study implies that different amendments of organic matter and gypsum may result in various responses and interactions of biological, chemical and physical processes, with implications for the carbon cycle in saline-alkaline soils of arid region.
Iterative and discrete reconstruction in the evaluation of the rabbit model of osteoarthritis
Authors: Ketola Juuso H. , Karhula Sakari S. , Finnilä Mikko A. J. , Korhonen Rami K. , Herzog Walter , Siltanen Samuli , Nieminen Miika T. , Saarakkala Simo
Published: August 2018

Micro-computed tomography (µCT) is a standard method for bone morphometric evaluation. However, the scan time can be long and the radiation dose during the scan may have adverse effects on test subjects, therefore both of them should be minimized. This could be achieved by applying iterative reconstruction (IR) on sparse projection data, as IR is capable of producing reconstructions of sufficient image quality with less projection data than the traditional algorithm requires. In this work, the performance of three IR algorithms was assessed for quantitative bone imaging from low-resolution data in the evaluation of the rabbit model of osteoarthritis. Subchondral bone images were reconstructed with a conjugate gradient least squares algorithm, a total variation regularization scheme, and a discrete algebraic reconstruction technique to obtain quantitative bone morphometry, and the results obtained in this manner were compared with those obtained from the reference reconstruction. Our approaches were sufficient to identify changes in bone structure in early osteoarthritis, and these changes were preserved even when minimal data were provided for the reconstruction. Thus, our results suggest that IR algorithms give reliable performance with sparse projection data, thereby recommending them for use in µCT studies where time and radiation exposure are preferably minimized.
Yu-Shiba-Rusinov bound states induced by a spin flipper in the vicinity of a s-wave superconductor
Authors: Pal Subhajit , Benjamin Colin
Published: August 2018

We theoretically study the formation and characteristics of Yu-Shiba-Rusinov bound states within the superconducting gap using a BTK approach in presence of a spin flipper (high spin magnetic impurity). We focus on the zero energy in the conductance spectra and show how a peak is formed at E = 0 due to flipping of the magnetic impurity spin, but for no flip case a dip forms at E = 0 in the conductance spectra. This E = 0 conductance peak is almost quantized at 2e2/h values, however it arises due to non-topological reasons in contrast to the E = 0 peak formed due to Majorana states.
Neural network identification of people hidden from view with a single-pixel, single-photon detector
Authors: Caramazza Piergiorgio , Boccolini Alessandro , Buschek Daniel , Hullin Matthias , Higham Catherine F. , Henderson Robert , Murray-Smith Roderick , Faccio Daniele
Published: August 2018

Light scattered from multiple surfaces can be used to retrieve information of hidden environments. However, full three-dimensional retrieval of an object hidden from view by a wall has only been achieved with scanning systems and requires intensive computational processing of the retrieved data. Here we use a non-scanning, single-photon single-pixel detector in combination with a deep convolutional artificial neural network: this allows us to locate the position and to also simultaneously provide the actual identity of a hidden person, chosen from a database of people (N = 3). Artificial neural networks applied to specific computational imaging problems can therefore enable novel imaging capabilities with hugely simplified hardware and processing times.
The functional relations among motor-based prediction, sensory goals and feedback in learning non-native speech sounds: Evidence from adult Mandarin Chinese speakers with an auditory feedback masking paradigm
Authors: Liu Xiaoluan , Tian Xing
Published: August 2018

Previous studies in speech production and acquisition have mainly focused on how feedback vs. goals and feedback vs. prediction regulate learning and speech control. The present study investigated the less studied mechanism–prediction vs. goals in the context of adult Mandarin speakers’ acquisition of non-native sounds, using an auditory feedback masking paradigm. Participants were asked to learn two types of non-native vowels: /ø/ and /ɵ/—the former being less similar than the latter to Mandarin vowels, either in feedback available or feedback masked conditions. The results show that there was no significant improvement in learning the two targets when auditory feedback was masked. This suggests that motor-based prediction could not directly compare with sensory goals for adult second language acquisition. Furthermore, auditory feedback can help achieve learning only if the competition between prediction and goals is minimal, i.e., when target sounds are distinct from existing sounds in one’s native speech. The results suggest motor-based prediction and sensory goals may share a similar neural representational format, which could result in a competing relation in neural recourses in speech learning. The feedback can conditionally overcome such interference between prediction and goals. Hence, the present study further probed the functional relations among key components (prediction, goals and feedback) of sensorimotor integration in speech learning.
Differential association of ezetimibe-simvastatin combination with major adverse cardiovascular events in patients with or without diabetes: a retrospective propensity score-matched cohort study
Authors: Lee Yong-ho , Hong Namki , Lee Chan Joo , Park Sung Ha , Lee Byung-Wan , Cha Bong-Soo , Kang Eun Seok
Published: August 2018

Clinical trials suggested that the benefits of ezetimibe-statin combination therapy on major adverse cardiovascular events (MACE) might be greater in patients with diabetes. We aimed to investigate the differential association of ezetimibe-statin combination with incident MACE by presence of diabetes. In this retrospective cohort study, subjects treated with simvastatin 20 mg plus ezetimibe 10 mg (S + E) or simvastatin 20 mg alone (S) between 2005 and 2015 were 1:1 matched using propensity score as stratified by diabetes. Primary outcome was newly-developed MACE composed of cardiovascular death, ACS, coronary revascularization, or non-hemorrhagic stroke. During 5,077 and 12,439 person-years, the incidence rates of MACE were 24.9, 20.1, 35.3, and 22.8/1000 person-years among no diabetes S, no diabetes S + E, diabetes S, and diabetes S + E, respectively. Relative to no diabetes S, adjusted HR (aHR) for MACE in diabetes S was 1.23 (p = 0.086), whereas S + E was associated with a lower risk of MACE in both non-diabetic patients (aHR 0.76, p = 0.047) and diabetic patients (aHR 0.60, p = 0.007) with significant difference (relative excess risk due to interaction = −0.39, p = 0.044). In conclusion, reduction of MACE risk associated with ezetimibe plus simvastatin therapy relative to simvastatin alone was greater in patients with diabetes than in patients without diabetes.
Schistosoma mansoni infection is associated with quantitative and qualitative modifications of the mammalian intestinal microbiota
Authors: Jenkins Timothy P. , Peachey Laura E. , Ajami Nadim J. , MacDonald Andrew S. , Hsieh Michael H. , Brindley Paul J. , Cantacessi Cinzia , Rinaldi Gabriel
Published: August 2018

In spite of the extensive contribution of intestinal pathology to the pathophysiology of schistosomiasis, little is known of the impact of schistosome infection on the composition of the gut microbiota of its mammalian host. Here, we characterised the fluctuations in the composition of the gut microbial flora of the small and large intestine, as well as the changes in abundance of individual microbial species, of mice experimentally infected with Schistosoma mansoni with the goal of identifying microbial taxa with potential roles in the pathophysiology of infection and disease. Bioinformatic analyses of bacterial 16S rRNA gene data revealed an overall reduction in gut microbial alpha diversity, alongside a significant increase in microbial beta diversity characterised by expanded populations of Akkermansia muciniphila (phylum Verrucomicrobia) and lactobacilli, in the gut microbiota of S. mansoni-infected mice when compared to uninfected control animals. These data support a role of the mammalian gut microbiota in the pathogenesis of hepato-intestinal schistosomiasis and serves as a foundation for the design of mechanistic studies to unravel the complex relationships amongst parasitic helminths, gut microbiota, pathophysiology of infection and host immunity.
High-resolution synchrotron-based X-ray microtomography as a tool to unveil the three-dimensional neuronal architecture of the brain
Authors: Fonseca Matheus de Castro , Araujo Bruno Henrique Silva , Dias Carlos Sato Baraldi , Archilha Nathaly Lopes , Neto Dionísio Pedro Amorim , Cavalheiro Esper , Westfahl Harry , da Silva Antônio José Roque , Franchini Kleber Gomes
Published: August 2018

The assessment of neuronal number, spatial organization and connectivity is fundamental for a complete understanding of brain function. However, the evaluation of the three-dimensional (3D) brain cytoarchitecture at cellular resolution persists as a great challenge in the field of neuroscience. In this context, X-ray microtomography has shown to be a valuable non-destructive tool for imaging a broad range of samples, from dense materials to soft biological specimens, arisen as a new method for deciphering the cytoarchitecture and connectivity of the brain. In this work we present a method for imaging whole neurons in the brain, combining synchrotron-based X-ray microtomography with the Golgi-Cox mercury-based impregnation protocol. In contrast to optical 3D techniques, the approach shown here does neither require tissue slicing or clearing, and allows the investigation of several cells within a 3D region of the brain.
Identification and characterization of a novel β-D-galactosidase that releases pyruvylated galactose
Authors: Higuchi Yujiro , Matsufuji Hitomi , Tanuma Masanari , Arakawa Takatoshi , Mori Kazuki , Yamada Chihaya , Shofia Risa , Matsunaga Emiko , Tashiro Kosuke , Fushinobu Shinya , Takegawa Kaoru
Published: August 2018

Pyruvyl modification of oligosaccharides is widely seen in both prokaryotes and eukaryotes. Although the biosynthetic mechanisms of pyruvylation have been investigated, enzymes that metabolize and degrade pyruvylated oligosaccharides are not well known. Here, we searched for a pyruvylated galactose (PvGal)-releasing enzyme by screening soil samples. We identified a Bacillus strain, as confirmed by the 16S ribosomal RNA gene analysis, that exhibited PvGal-ase activity toward p-nitrophenyl-β-D-pyruvylated galactopyranose (pNP-β-D-PvGal). Draft genome sequencing of this strain, named HMA207, identified three candidate genes encoding potential PvGal-ases, among which only the recombinant protein encoded by ORF1119 exhibited PvGal-ase activity. Although ORF1119 protein displayed broad substrate specificity for pNP sugars, pNP-β-D-PvGal was the most favorable substrate. The optimum pH for the ORF1119 PvGal-ase was determined as 7.5. A BLAST search suggested that ORF1119 homologs exist widely in bacteria. Among two homologs tested, BglC from Clostridium but not BglH from Bacillus showed PvGal-ase activity. Crystal structural analysis together with point mutation analysis revealed crucial amino acids for PvGal-ase activity. Moreover, ORF1119 protein catalyzed the hydrolysis of PvGal from galactomannan of Schizosaccharomyces pombe, suggesting that natural polysaccharides might be substrates of the PvGal-ase. This novel PvGal-catalyzing enzyme might be useful for glycoengineering projects to produce new oligosaccharide structures.
Post-Deposition Wetting and Instabilities in Organic Thin Films by Supersonic Molecular Beam Deposition
Authors: Chiarella Fabio , Perroni Carmine Antonio , Chianese Federico , Barra Mario , De Luca Gabriella Maria , Cataudella Vittorio , Cassinese Antonio
Published: August 2018

We discuss the formation and post-deposition instability of nanodrop-like structures in thin films of PDIF-CN2 (a perylene derivative) deposited via supersonic molecular beam deposition technique on highly hydrophobic substrates at room temperature. The role of the deposition rate on the characteristic lengths of the organic nanodrops has been investigated by a systematic analysis of atomic force microscope images of the thin films and through the use of the height-height correlation function. The nanodrops appear to be a metastable configuration for the freshly-deposited films. For this reason, post-deposition wetting effect has been examined with unprecedented accuracy throughout a year of experimental observations. The observed time scales, from few hours to months, are related to the growth rate, and characterize the thin films morphological reordering from three-dimensional nanodrops to a well-connected terraced film. While the interplay between adhesion and cohesion energies favors the formation of 3D-mounted structures during the growth, wetting phenomenon following the switching off of the molecular flux is found to be driven by an instability. A slow rate downhill process survives at the molecular flux shutdown and it is accompanied and maybe favored by the formation of a precursor layer composed of more lying molecules. These results are supported by simulations based on a non-linear stochastic model. The instability has been simulated, for both the growth and the post-growth evolution. To better reproduce the experimental data it is needed to introduce a surface equalizer term characterized by a relaxation time taking into account the presence of a local mechanism of molecular correlation.
The landscape of the A-to-I RNA editome from 462 human genomes
Authors: Ouyang Zhangyi , Ren Chao , Liu Feng , An Gaole , Bo Xiaochen , Shu Wenjie
Published: August 2018

A-to-I editing, as a post-transcriptional modification process mediated by ADAR, plays a crucial role in many biological processes in metazoans. However, how and to what extent A-to-I editing diversifies and shapes population diversity at the RNA level are largely unknown. Here, we used 462 mRNA-sequencing samples from five populations of the Geuvadis Project and identified 16,518 A-to-I editing sites, with false detection rate of 1.03%. These sites form the landscape of the RNA editome of the human genome. By exploring RNA editing within and between populations, we revealed the geographic restriction of rare editing sites and population-specific patterns of edQTL editing sites. Moreover, we showed that RNA editing can be used to characterize the subtle but substantial diversity between different populations, especially those from different continents. Taken together, our results demonstrated that the nature and structure of populations at the RNA level are illustrated well by RNA editing, which provides insights into the process of how A-to-I editing shapes population diversity at the transcriptomic level. Our work will facilitate the understanding of the landscape of the RNA editome at the population scale and will be helpful for interpreting differences in the distribution and prevalence of disease among individuals and across populations.
A Low-Cost Non-explosive Synthesis of Graphene Oxide for Scalable Applications
Authors: Ranjan Pranay , Agrawal Shweta , Sinha Apurva , Rao T. Rajagopala , Balakrishnan Jayakumar , Thakur Ajay D.
Published: August 2018

A low cost, non-explosive process for the synthesis of graphene oxide (GO) is demonstrated. Using suitable choice of reaction parameters including temperature and time, this recipe does not require expensive membranes for filtration of carbonaceous and metallic residues. A pre-cooling protocol is introduced to control the explosive nature of the highly exothermic reactions during the oxidation process. This alleviates the requirement for expensive membranes and completely eliminates the explosive nature of intermediate reaction steps when compared to existing methods. High quality of the synthesized GO is corroborated using a host of characterization techniques including X-ray diffraction, optical spectroscopy, X-ray photoemission spectroscopy and current-voltage characteristics. Simple reduction protocol using ultra-violet light is demonstrated for potential application in the area of photovoltaics. Using different reduction protocols together with the proposed inexpensive method, reduced GO samples with tunable conductance over a wide range of values is demonstrated. Density functional theory is employed to understand the structure of GO. We anticipate that this scalable approach will catalyze large scale applications of GO.