bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative interactions between total and specific enzyme activities and C and N contents in earthworm‐affected pear orchard soil
Authors: Brzezińska Małgorzata , Lipiec Jerzy , Frąc Magdalena , Oszust Karolina , Szarlip Paweł , Turski Marcin
Published: July 2018

The current study describes quantitatively the interactions between (a) activity of extracellular enzymes: β‐glucosidase (BG), protease (Prot), alkaline phosphatase (Alk P), and acid phosphatase (Acid P); (b) intracellular activities: respiration, dehydrogenase activity (DHA); and (c) C and N contents of soil: Corg—organic carbon, Cmic—microbial biomass, ratio Cmic:Corg, Ntot—total nitrogen, and ratio C:N in earthworm‐affected and surrounding loess soil under a pear orchard. The soil tested was collected from: burrow walls (0–3 mm) and a transition zone (3–7 mm) both forming drilosphere, bulk soil (20 mm from the burrow wall), and cast aggregates. The enzyme activities were presented as total ‘tot’ (per gram of dry soil mass) and specific ‘spec’ (per Cmic). It was shown that soil Cmic, basal respiration, BGtot, Prottot, and Alk Ptot were significantly positively correlated with Corg, Cmic:Corg, Ntot, and C:N (r = 0.627–0.976). However, the specific BGspec, Protspec, and Acid Pspec were negatively correlated, while specific respiration (qCO2) and Alk Pspec were not correlated with most soil characteristics. The relationships between DHAtot, DHAspec, and all soil characteristics were positive and had the highest correlation coefficients (r = 0.703–0.989). Response ratio of the enzyme activity was more strongly affected by enzyme activity location (extracellular vs. intracellular) and presentation method (total vs. specific), than by earthworm‐affected soil compartments. The results suggest a need to consider the method of enzyme activity presentation (specific vs. total) that supports understanding ecologically relevant microbial processes in earthworm‐inhabited orchard soils.
Accelerated MR parameter mapping with a union of local subspaces constraint
Authors: Mandava Sagar , Keerthivasan Mahesh B. , Li Zhitao , Martin Diego R. , Altbach Maria I. , Bilgin Ali
Published: July 2018

Purpose

A new reconstruction method for multi‐contrast imaging and parameter mapping based on a union of local subspaces constraint is presented.

Theory

Subspace constrained reconstructions use a predetermined subspace to explicitly constrain the relaxation signals. The choice of subspace size

impacts the approximation error vs noise‐amplification tradeoff associated with these methods. A different approach is used in the model consistency constraint (MOCCO) framework to leverage the subspace model to enforce a softer penalty. Our proposed method, MOCCO‐LS, augments the MOCCO model with a union of local subspaces (LS) approach. The union of local subspaces model is coupled with spatial support constraints and incorporated into the MOCCO framework to regularize the contrast signals in the scene.

Methods

The performance of the MOCCO‐LS method was evaluated in vivo on T1 and T2 mapping of the human brain and with Monte‐Carlo simulations and compared against MOCCO and the explicit subspace constrained models.

Results

The results demonstrate a clear improvement in the multi‐contrast images and parameter maps. We sweep across the model order space

to compare the different reconstructions and demonstrate that the reconstructions have different preferential operating points. Experiments on T2 mapping show that the proposed method yields substantial improvements in performance even when operating at very high acceleration rates.

Conclusions

The use of a union of local subspace constraints coupled with a sparsity promoting penalty leads to improved reconstruction quality of multi‐contrast images and parameter maps.
Multi‐parametric T2* magnetic resonance fingerprinting using variable echo times
Authors: Wyatt Cory R. , Smith Travis B. , Sammi Manoj K. , Rooney William D. , Guimaraes Alexander R.
Published: July 2018

The use of quantitative imaging biomarkers in the imaging of various disease states, including cancer and neurodegenerative disease, has increased in recent years. T1, T2, and T2* relaxation time constants have been shown to be affected by tissue structure or contrast infusion. Acquiring these biomarkers simultaneously in a multi‐parametric acquisition could provide more robust detection of tissue changes in various disease states including neurodegeneration and cancer. Traditional magnetic resonance fingerprinting (MRF) has been shown to provide quick, quantitative mapping of T1 and T2 relaxation time constants. In this study, T2* relaxation is added to the MRF framework using variable echo times (TE).

To demonstrate the feasibility of the method and compare incremental and golden angle spiral rotations, simulated phantom data was fit using the proposed method. Additionally, T1/T2/T2*/δf MRF as well as conventional T1, T2, and T2* acquisitions were acquired in agar phantoms and the brains of three healthy volunteers.

Golden angle spiral rotation was found to reduce inaccuracy resulting from off resonance effects. Strong correlations were found between conventional and MRF values in the T1, T2, and T2* relaxation time constants of the agar phantoms and healthy volunteers.

In this study, T2* relaxation has been incorporated into the MRF framework by using variable echo times, while still fitting for T1 and T2 relaxation time constants. In addition to fitting these relaxation time constants, a novel method for fitting and correcting off resonance effects has been developed.
Synthesis of a novel hyperbranched and phosphorus‐containing charring‐foaming agent and its application in polypropylene
Authors: Zhu Changjiang , He Mingshan , Cui Jianguang , Tai Qilong , Song Lei , Hu Yuan
Published: July 2018

In this work, a novel hyperbranched and phosphorus‐containing triazine derivative (HPCFA) is synthesized. HPCFA is used as charring‐foaming agent and combined with ammonium polyphosphate (APP) as intumescent flame retardant to flame retard polypropylene (PP). PP/HPCFA/APP composite can achieve limited oxygen index value of 31% and pass UL 94V‐0 rating by addition of 20 wt% HPCFA/APP (1/2, w/w). Besides, HPCFA is compared with another hyperbranched charring‐foaming agent (HCFA). HPCFA and HCFA have similar chemical structure, and their only difference is that HPCFA has phosphorus‐containing unit in the main chain compared with HCFA. HPCFA/APP system exhibits superior flame retardancy compared with HCFA/APP system. Char residue analysis demonstrates that HPCFA/APP system can form denser and more compact char layer in comparison with that of HCFA/APP system.
Overview on natural hydrophilic polysaccharide polymers in drug delivery
Authors: Abedini Fatemeh , Ebrahimi Mohammad , Roozbehani Abbas Hemmati , Domb Abraham J. , Hosseinkhani Hossein
Published: July 2018

Nanotechnology is poised to make potentially revolutionary innovations in areas of biomedical science, such as gene therapy and drug therapy. A recently developed nanodelivery strategy involves the use of hydrophilic polymers as carriers of proteins and siRNA. By controlling the reaction conditions during polymer production, various degrees of anionic charge, cationic charge, and cross‐linking can be added, thereby changing their capabilities as protein and nucleic acid carriers and promoting effective cell membrane permeation. The efficiency of a specific controlled‐release polymeric system is determined in part by its unique physical and chemical properties and biodegradation rate. In this review, we will summarize recent progress in the ability to modify drug release of hydrophilic polymers nanoparticles.
Exendin‐4 enhances radiation response of prostate cancer
Authors: He Wenjing , Li Junhe
Published: July 2018

Background

Exendin‐4, one of the most widely used antidiabetic drugs, has recently been reported to have potential antitumor effects in cancers. Prostate cancer (PC) is one of the most common cancers in male patients with type 2 diabetes mellitus, and radiotherapy plays a vital role in the therapy of PC. Whether exendin‐4 has the potential to enhance PC response to ionizing radiation (IR) remains unknown. We aimed to explore whether exendin‐4 radiosensitizes PC cells.

Methods

GLP‐1 receptor (GLP‐1R) expression in PC tissue samples and cell lines were analyzed, Human prostate cancer cells (PC3 and LNCap) were treated with IR and exendin‐4, and subjected to proliferation, clone formation, cell cycle, immunoblotting, and immunohistochemical analysis. An in situ prostate tumor of animal model was established.

Results

We found that GLP‐1R was expressed in human PC tissues and cell lines. 1‐100 nM exendin‐4 promoted the anti‐proliferation effects of IR in vitro and in vivo, and enhanced radiation‐induced G2/M cycle arrest in PC cells in a dose‐dependent manner. Furthermore, Ex‐4 increased AMPK phosphorylation, decrease the levels of p‐mTOR, cyclin B, and p34cdc2.

Conclusions

Our study suggested exendin‐4 radiosensitizes PC cells via activation of AMPK A and subsequent inhibition of p‐mTOR, cyclin B, and p34cdc2 activation.
Further applications of classical amide coupling reagents: Microwave‐assisted esterification on solid phase
Authors: Takayama Risa , Hayakawa Shun , Hinou Hiroshi , Albericio Fernando , Garcia‐Martin Fayna
Published: July 2018

Ester linkage (s) is a key chemical connector in organic chemistry, including natural products, peptides, and synthetic polymers. We herein describe a straightforward method for the efficient formation of ester linkage (s) on solid‐phase. This method simply involves the use of amide coupling reagents under microwave irradiation. The robustness of this method relies on the use of classical solid‐phase coupling reagents, heating by microwave irradiation, and a short time period, which results in high yields and the minimization of racemization.
Racemic crystal structures of peptide toxins, GsMTx4 prepared by protein total synthesis
Authors: Qu Qian , Gao Shuai , Li Yi‐Ming
Published: July 2018

The Piezo channel is a versatile mechanosensitive cation channel that mediates tactile, vascular development, and proprioception. GsMTx4 is the only reported inhibitor specifically targeting Piezo channels. Although the sequence of GsMTx4 is reported, the crystal structure of GsMTx4 is still unknown. Here, we achieved the two‐segment synthesis of GsMTx4 and its enantiomer, enGsMTx4, through hydrazide based Native Chemical Ligation, and analyzed the crystal structure of GsMTx4 through the racemic crystallization technology. By analyzing the structure, we found that there is a hydrophobic patch surrounded by aromatic residues and charged residues.
Quantification of hydrolyzed peptides and proteins by amino acid fluorescence
Authors: Allenspach Martina D. , Fuchs Jens A. , Doriot Nicolas , Hiss Jan A. , Schneider Gisbert , Steuer Christian
Published: July 2018

Reliable quantification of peptides and proteins is essential for drug discovery. We report the successful development and validation of an accurate and broadly applicable high performance liquid chromatography hyphenated to fluorescence detector procedure for the quantitative determination of the aromatic amino acids tyrosine, phenylalanine, and tryptophan, without relying on derivatization chemistry. Using ion‐pair chromatography, fluorescent amino acids were clearly separated within 10 minutes. The hydrolysis of peptides was performed under acidic and heated conditions to yield the monomeric building blocks. Various protecting agents were tested to ensure tryptophan stability. The presented analytical method accurately (>95%) quantifies all fluorescent residues. The power of the method was confirmed by correct quantification of protein reference standard to 98.6% over all fluorescence traces. The method allowed us to identify pre‐analytical differences between the nominal and actual concentrations of 12 peptide solutions. Salt formation, weighing errors, and other pre‐analytical pitfalls resulted in noteworthy differences of up to 85% between the indicated and actual concentration of peptide solutions, subsequently leading to false positive or negative interpretation of activity data. Finally, only one solution is needed to perform quantification as well as UV‐purity tests and can further be used as stock solution for activity testing.
Fabrication and Characterization of (Ba,La)SnO3 Semiconducting Epitaxial Films on (111) and (001) SrTiO3 Substrates
Authors: Miura Kohei , Kiriya Daisuke , Yoshimura Takeshi , Ashida Atsushi , Fujimura Norifumi
Published: July 2018

Recently, BaSnO3 has attracted great attention as a promising transparent oxide semiconductor with a large bandgap (3.3 eV) and high mobility (320 cm2 V−1 s−1), and many reports have discussed the origin of its high mobility. Specifically, its effective mass m* has been investigated with both calculations and experiments. First‐principles calculations have suggested that m* is small near the Γ point and that this m* assists the high mobility. Therefore, it is quite important to study the anisotropy in the mobility of this material. However, except for (001) BaSnO3, there are almost no reports on the electrical transport properties of the films with other orientations. In this paper, the authors fabricate (111) and (001) (Ba,La)SnO3 films by using pulsed laser deposition to evaluate the structural differences including the epitaxial strain and the orientation distribution generated from the differences in the growth mode that is originated in the ionic arrangement of each surface. The effects of the structural differences for the conductivities of (001) and (111) films and how do the authors achieve the epitaxial films with high mobility are discussed.
Receiver station in Budapest for Q/V band satellite site diversity and adaptive coding and modulation experiments with Alphasat
Authors: Csurgai‐Horváth László
Published: July 2018

The European Space Agency in cooperation with Inmarsat launched the Alphasat communication satellite in 2013, which hosts four technology demonstration payloads. One of them is the Aldo Paraboni payload composed of the Q/V band communication and Ka/Q band propagation experiments. The payload and the communication experiment are funded by the Italian Space Agency. Budapest University of Technology, Hungary in cooperation with Joanneum Research, Austria built a receiver station to conduct site diversity and adaptive coding and modulation experiments over the Q/V band satellite channel. The transmitter/receiver station in Austria and the receiver station in Hungary form a long‐distance diversity system that is used to investigate the capabilities of the adaptive technique under various propagation conditions controlled by the local signal quality at the receiver site in Budapest. This paper provides a detailed overview of the diversity station in Budapest. The operation of the adaptive coding and modulation experiment is illustrated with measurements performed in 2017.
Mixed‐monolayer of N‐hydroxysuccinimide‐terminated cross‐linker and short alkanethiol to improve the efficiency of biomolecule binding for biosensing
Authors: Ataman Sadık Demet , Eksi‐Kocak Haslet , Ertaş Gülay , Boyacı İsmail Hakkı , Mutlu Mehmet
Published: July 2018

The goal of this study was to use a novel surface chemistry for modifying gold surfaces to decrease the steric hindrance, minimize the nonspecific bindings while providing directed immobilization of proteins for advancing the transducer property and to provide a biosensing platform for surface plasmon resonance (SPR) applications. Mixed self‐assembled monolayers (mSAMs) were prepared using 3,3′‐Dithiodipropionic acid di (N‐hydroxysuccinimide ester) (DSP) and 6‐mercapto‐1‐hexanol (MCH) and the selected model proteins bovine serum albumin (BSA) and lysozyme were tested for binding efficiency. First, binding of these two proteins at constant concentration to different DSP:MCH mSAMs were compared to deduce the best molar ratio for forming mSAM using a continuous flow system coupled to SPR. Coincidently the maximum protein binding DSP:MCH mSAM were the same for both proteins. The change in Response Unit (∆RU) signal due to protein binding between DSP SAM and maximum protein binding DSP:MCH mSAM for lysozyme binding was more in comparison to BSA binding. Second, the effect of BSA and lysozyme concentration on binding efficiency to maximum protein binding DSP:MCH mSAM were compared and discussed. Lysozyme and BSA were shown to reach saturations on the same monolayer at concentrations of 5.7x10−5 and 8.96x10−6 [M] respectively, hence the molar ratio for limit concentrations is 6:1. The DSP SAM, MCH SAM, and DSP:MCH mSAMs where maximum and minimum protein binding occurs were also characterized with XPS and Attenuated total reflectance‐Fourier transform infrared (ATR‐FTIR) spectroscopy. Blank gold surface, maximum protein binding DSP:MCH mSAM and BSA immobilized DSP:MCH mSAM on gold surface were also investigated utilizing tapping mode AFM.
Comparison of two correlated ROC surfaces at a given pair of true classification rates
Authors: Bantis Leonidas E. , Feng Ziding
Published: July 2018

The receiver operating characteristic (ROC) curve is typically employed when one wants to evaluate the discriminatory capability of a continuous or ordinal biomarker in the case where two groups are to be distinguished, commonly the “healthy” and the “diseased.” There are cases for which the disease status has three categories. Such cases employ the ROC surface, which is a natural generalization of the ROC curve for three classes. In this paper, we explore new methodologies for comparing two continuous biomarkers that refer to a trichotomous disease status, when both markers are applied to the same patients. Comparisons based on the volume under the surface have been proposed before, but that measure is often not clinically relevant. Here, we focus on comparing two correlated ROC surfaces at given pairs of true classification rates, which are more relevant to patients and physicians. We propose delta‐based parametric techniques, power transformations to normality, and bootstrap‐based smooth nonparametric techniques to investigate the performance of an appropriate test. We evaluate our approaches through an extensive simulation study and apply them to a real dataset from prostate cancer screening.
Graphene Oxide: An Efficient Carbocatalyst for the Facile Synthesis of Isoindolo[2, 1‐a]quinazoline‐5,11‐diones via Domino Condensation under Solvent‐Free Conditions
Authors: Bodhak Chandan , Hazra Subhenjit , Pramanik Animesh
Published: July 2018

An efficient and environmentally benign synthetic method has been developed for the library synthesis of biologically important multi‐functionalized isoindolo[2, 1‐a]quinazolines by two component domino condensation of 2‐carboxybenzaldehyde and 2‐aminobenzohydrazides/2‐aminobenzamides using graphene oxide (GO) as catalyst under solvent free conditions. The solvent‐free strategy exploiting inexpensive and eco‐compatible GO as mild carbocatalyst with large surface area is the major significant advantage of the present protocol. Furthermore, low catalyst loading, good to excellent yield of the products and easy recovery and recyclability of GO attribute considerable supremacy to the present protocol.
A Model for Predicting Residual Hydrogen Content in Blooms and Billets Stacked in Large Industrial Piles
Authors: Colla Valentina , Valentini Renzo , Vannucci Marco
Published: July 2018

Hydrogen is highly detrimental for mechanical properties and internal quality of steel products. Hydrogen is captured in liquid steel from different sources, also depending on the different stages of the manufacturing process. During the liquid stages, the most effective countermeasure to reduce the hydrogen content is vacuum degassing. Nonetheless, not all the products undergo this process and then the cooling stage becomes fundamental to avoid hydrogen embrittlement phenomena. To be effective for hydrogen release, the cooling path needs to be suitably slow without abrupt temperature gradients. In industry, products are piled according to strategies following logistic rather than metallurgical logics, with very poor control of the cooling strategy. The paper presents a simplified and practical model, which predicts the final hydrogen content in blooms and billets with square or rectangular section after the slow cooling in a large pile by computing the cooling path of each product. The model allows identifying those products, where the residual hydrogen content after cooling is excessive, which are therefore more likely to show hydrogen embrittlement‐related problems. It allows simulation of different piling strategies for each specific product and is therefore useful in order to preliminarily identify the best piling procedure to avoid hydrogen embrittlement.
Optimal parameters of volt‐var functions for photovoltaic smart inverters in distribution networks
Authors: Dao Van Tu , Ishii Hideo , Hayashi Yasuhiro
Published: July 2018

This paper considers two basic smart inverter functions, volt‐var and volt‐watt control of photovoltaic (PV) generations, as options for power utilities to improve the system performance. Using forecast solar irradiance and load demand, parameters of the volt‐var function are optimally adjusted to reduce the active power curtailment resulting from a preset volt‐watt function. This adjustment is performed in coordination with a step voltage regulator to minimize the social cost derived from daily energy loss and solar generation curtailment. On the day of operation, an adaptive control is applied to each PV system to deal with the potential difference between the predicted and the actual solar irradiance. Effectiveness of the proposed method is well illustrated through time‐series simulations of a tested system containing a 6.6‐kV feeder, which accommodates large‐scale PVs and low‐voltage networks with many rooftop solar panels. Results show that appropriate volt‐var settings can remedy the high‐voltage issue caused by high PV generation and that the conflicts between loss reduction and solar energy exploitation efforts can be solved successfully for a given scenario of electricity prices. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Introduction
Authors: Pohjolainen Seppo , Myllykoski Tuomas , Mercat Christian , Sosnovsky Sergey
Published: July 2018

This chapter presents motivation, goals, and organisational details of two EU projects: MathGeAr and MetaMath, funded by the EU Tempus programme. The goal was to study and improve mathematics education for STEM specialisations in Russian (MetaMath) and Georgian/Armenian (MathGeAr) universities. The analysis carried out in the beginning of the two projects and described in this book has been followed up by modernisation and piloting phases. Special attention has been paid to the introduction of modern educational technologies, such as the intelligent multifunctional platform Math-Bridge used as an online component of modernised mathematical courses.

The first section discusses the importance of mathematics as a part of the engineering sciences and education and global challenges caused by lack of student motivation and relatively high drop-out rates. New learning approaches are needed to increase students’ motivation. These approaches can be supported by using information and communication technology.

The second section introduces the two parallel projects MetaMath and MathGeAr, with their goals and organisational details, and their participants from the EU, Russia, Georgia, and Armenia. An essential part of the project is modernisation of selected courses with a special focus on technology-enhanced learning.

Students’ perceptions of mathematics have impact on their motivation and performance. In a broader sense they contain cultural differences between nations and institutions. The third section studies engineering mathematics students’ perceptions at all the universities participating in the project by analysing an online survey carried out among the students.
Methodology for Comparative Analysis of Courses
Authors: Sosnovsky Sergey
Published: July 2018

This chapter outlines the methodology for the comparative analysis of mathematics courses taught in participating Russian, Georgian, Armenian and EU universities to the students of technical and engineering programmes. It identifies a range of factors, based on which the courses have been compared, and it provides recommendations on performing the comparison. The most important part of the comparison is finding the correspondence between the actual content taught in counterpart courses of the two target universities. In order to perform this comparison in a meaningful way, the we needed a certain instrument, enabling consistent characterisation of the content of the compared courses in terms of the mathematical knowledge involved. We adopted the SEFI Framework for Mathematics Curricula in Engineering Education (SEFI, 2013) for these purposes.
Overview of Engineering Mathematics Education for STEM in Russia
Authors: Pokholkov Yury , Zaitseva Kseniya , Kuprianov Mikhail , Baskakov Iurii , Pozdniakov Sergei , Ivanov Sergey , Chukhnov Anton , Kolpakov Andrey , Posov Ilya , Rybin Sergey , Akimushkin Vasiliy , Syromiasov Aleksei , Soldatenko Ilia , Zakharova Irina , Yazenin Alexander
Published: July 2018

Higher education in general and engineering education in particular are divided into three levels in Russia. The first level is the Bachelor’s degree course; the second level is the specialist and Master’s degree program; the third level is the postgraduate training program.
Overview of Engineering Mathematics Education for STEM in EU
Authors: Pohjolainen Seppo , Myllykoski Tuomas , Mercat Christian , Sosnovsky Sergey
Published: July 2018

This chapter introduces engineering mathematics education in the EU, especially in the participating countries Finland and France. Their educational systems correspond to each other to some extent, but still differ in many aspects. Special emphasis is on the curricula of Tampere University of Technology and University of Lyon. The engineering curricula of these universities contains comparable amount of engineering mathematics depending on the engineering study program. Normally the courses are taught in the beginning of studies. As mathematics is a universal language, the contents of the courses are well comparable.
Case Studies of Math Education for STEM in Armenia
Authors: Pohjolainen Seppo , Myllykoski Tuomas , Mercat Christian , Sosnovsky Sergey
Published: July 2018

Armenian State Pedagogical University (ASPU) was established on November 7, 1922 and in 1948 it was named after the great Armenian Enlightener Educator Khachatur Abovian. ASPU implements a three-level education system (Bachelor, Master and Doctorate studies). It has ten faculties.
Influence of Tertiary Gamma Prime (γ′) Size Evolution on Dwell Fatigue Crack Growth Behavior in CG RR1000
Authors: Schulz F. , Li H. Y. , Kitaguchi H. , Child D. , Williams S. , Bowen P.
Published: July 2018

This work investigates coarsening behavior of strengthening precipitates (γ′) in coarse-grained RR1000 after isothermal exposure for various times (50 to 500 hours) at 700 °C and 750 °C. The impact of these isothermal treatments is then studied by carrying out dwell (1 hour) fatigue crack growth tests at 700 °C in air. Such dwell periods can increase crack growth rates by nearly two orders of magnitude compared with baseline (0.25 Hz trapezoidal waveform) fatigue crack growth tests. Predominantly, scanning electron microscopy was used for γ′ analysis. Transmission electron microscopy was also utilized when necessary. Overaging as a thermodynamically driven and diffusion-controlled process strongly affects tertiary γ′ precipitates for the temperatures and treatment times investigated here. No influence of overaging on baseline fatigue behavior is observed. However, after overaging at 750 °C for 500 hours (which increases the mean tertiary γ′ size by a factor of two from 17 to 37 nm), dwell crack growth rates at 700 °C are reduced by one order of magnitude. Increased dwell fatigue crack growth resistance is also measured after overaging for 100 hours at 700 °C. The potential influence of γ′ distributions on dwell fatigue crack growth resistance is discussed in terms of stress relaxation behavior during dwell periods.
Geochemical features and genesis of continental cobalt-rich ferromanganese crusts
Authors: Maksimov S.O. , Safronov P.P.
Published: July 2018

Mass cobalt-rich ferromanganese microcrusts and nodules similar in morphology and chemical composition to cobalt-rich ferromanganese deep-ocean crusts were found in Cenozoic volcanic rocks in southern Primorye. Research has shown that ore genesis of this type is genetically related to argillization and destruction of siliceous rocks by CO2-rich fluids, which is confirmed by experimental data on carbon erosion of iron-containing materials. Two types of this fluid ore genesis are recognized: (1) relatively high-temperature (vapor–condensate), related to late volcanic processes and fracture gas infiltration, and (2) low-temperature (vapor–liquid–condensate), controlled by degassing followed by carbon mobilization (gasification). Primarily colloidal ferromanganese segregations have high contents of Co, Ni, Pb, Cu, and Ce, typical of oceanic ore genesis. Regardless of the concentrations of these metals in the protoliths, their contents in microcrusts are similar (n–10n wt.%). This indicates the same ore genesis mechanism and similar sorption properties of the colloidal ferromanganese material formed. Barium- and cerium-rich ferromanganese microcrusts and nodules are abundant. Condensed drops of iron-containing platinum were found in apobasaltic nickel-rich ferromanganese segregations. There is a cerium paradox expressed as a minimum or a total lack of cerium among rare-earth phosphates associated with ferromanganese microcrusts. Fluid destruction and oxide metallization of ocean-floor basalts are assumed to be the main source of metals for oceanic ferromanganese crusts and nodules.
ALPS: the Arbitrary Linear Plasma Solver
Authors: Verscharen D. , Klein K. G. , Chandran B. D. G. , Stevens M. L. , Salem C. S. , Bale S. D.
Published: July 2018

The Arbitrary Linear Plasma Solver (ALPS) is a parallelised numerical code that solves the dispersion relation in a hot (even relativistic) magnetised plasma with an arbitrary number of particle species with arbitrary gyrotropic equilibrium distribution functions for any direction of wave propagation with respect to the background field. ALPS reads the background momentum distributions as tables of values on a$(p_{\bot },p_{\Vert })$grid, where$p_{\bot }$and$p_{\Vert }$are the momentum coordinates in the directions perpendicular and parallel to the background magnetic field, respectively. We present the mathematical and numerical approach used by ALPS and introduce our algorithms for the handling of poles and the analytic continuation for the Landau contour integral. We then show test calculations of dispersion relations for a selection of stable and unstable configurations in Maxwellian, bi-Maxwellian,$\unicode[STIX]{x1D705}$-distributed and Jüttner-distributed plasmas. These tests demonstrate that ALPS derives reliable plasma dispersion relations. ALPS will make it possible to determine the properties of waves and instabilities in the non-equilibrium plasmas that are frequently found in space, laboratory experiments and numerical simulations.
The global biogeography of avian haemosporidian parasites is characterized by local diversification and intercontinental dispersal
Authors: Ellis Vincenzo A. , Sari Eloisa H. R. , Rubenstein Dustin R. , Dickerson Rebecca C. , Bensch Staffan , Ricklefs Robert E.
Published: July 2018

The biogeographic histories of parasites and pathogens are infrequently compared with those of free-living species, including their hosts. Documenting the frequency with which parasites and pathogens disperse across geographic regions contributes to understanding not only their evolution, but also the likelihood that they may become emerging infectious diseases. Haemosporidian parasites of birds (parasite generaPlasmodium,HaemoproteusandLeucocytozoon) are globally distributed, dipteran-vectored parasites. To date, over 2000 avian haemosporidian lineages have been designated by molecular barcoding methods. To achieve their current distributions, some lineages must have dispersed long distances, often over water. Here we quantify such events using the global avian haemosporidian database MalAvi and additional records primarily from the Americas. We scored lineages as belonging to one or more global biogeographic regions based on infection records. Most lineages were restricted to a single region but some were globally distributed. We also used part of the cytochromebgene to create genus-level parasite phylogenies and scored well-supported nodes as having descendant lineages in regional sympatry or allopatry. Descendant sister lineages ofPlasmodium,HaemoproteusandLeucocytozoonwere distributed in allopatry in 11, 16 and 15% of investigated nodes, respectively. Although a small but significant fraction of the molecular variance in cytochromebof all three genera could be explained by biogeographic region, global parasite dispersal likely contributed to the majority of the unexplained variance. Our results suggest that avian haemosporidian parasites have faced few geographic barriers to dispersal over their evolutionary history.
Accepting, active and in control: older women's experiences of ageing with peripheral arterial disease
Authors: Bassett Kimberley , Gullifer Judith , Varcoe Ramon L.
Published: July 2018

The population of Australia is ageing, with women being the primary beneficiaries of this increase in longevity. Increasingly older individuals are being diagnosed with different chronic illnesses such as peripheral arterial disease (PAD) which causes blockages of the blood vessels in the legs resulting in pain, non-healing ulcers, immobility and the potential amputation of the threatened limb. PAD has been traditionally thought to affect men more than women. Resultingly, women have been under-represented in clinical trials of PAD and under-diagnosed in the health-care setting. However, it has recently been acknowledged that women are indeedmorelikely to suffer from PAD than men due to increased presence of disease and survival advantage. As such, very little is known about women's understanding of and the meaning they create of their experiences of PAD. Therefore, how older women with PAD experience the ageing process is the focus of this qualitative research project. Interviews were conducted with 11 women from Sydney, Australia aged over 65 years who had been diagnosed with PAD. The interviews were analysed using an inductive thematic analysis. Three manifest themes were constructed: independence and control, active and involved, and the acceptance of ageing. These findings emphasised the idea that despite the presence of a chronic illness and increased age, remaining independent and engaged with life was vital to these women's wellbeing. Their subjective experiences of ageing reflect the fact that by adapting to the physical, mental and social changes that come with growing older, the focus does not need to be on loss and decline but rather can be about the continuation of life that can be both positive and meaningful.
Australian attitudes to intergenerational equity: impacts of social and policy change
Authors: Kendig Hal , Hussain Rafat , O'Loughlin Kate , Cannon Lisa
Published: July 2018

Attitudes to ageing can predispose decision-making as governments, interest groups and electorates negotiate competing demands in the context of economic constraints and social change. This paper, based on national survey data, investigates change and stability in Australian attitudes to intergenerational equity from 2009–2010 to 2015–2017, alongside concurrent socio-economic and policy change as well as cohort succession. The emphasis is on the baby-boom cohort who are viewed as significant beneficiaries of social change relative to opportunities of younger and older cohorts. Views of older people as a needy group may be changing slightly as more enter later life with substantial wealth and resources. Our results show that there is little perception of intergenerational conflict with the exception of the Millennial cohort whose life chances are compromised by economic and expenditure constraint over the past decade. Overall, attitudes remain sympathetic to older people, especially among women and people rendered vulnerable by poor health, non-home-ownership and low socio-economic positions. The findings do not align with government portrayals of intergenerational inequalities notwithstanding many having negative views of the future and ongoing expenditure restraint strategies. At what appears to be a critical turning point in the life chances of successive cohorts, the findings indicate the interplay between attitudes and social and policy change, as well as implications for social equity and processes of attitudinal change.
Heterogeneity formation within biofilm systems
Authors: ARISTOTELOUS ANDREAS C. , GRABOVSKY YURY , KLAPPER ISAAC
Published: July 2018

Biofilms, and collections of embedded microbial communities, present structural heterogeneities with functional consequences for important processes, such as transport. The origin of such structures has been unclear. Here, we propose that they can arise as a consequence of diffusive transport limitation. To illustrate, a model allowing internal heterogeneity is developed. Linear analysis is applied to a simplified version of the model suggesting that heterogeneity forms on (or below) the active layer length, a length scale that may not be suitable for homogenization, with non-trivial implications for system scale properties such as reduction in system-wide diffusive transport efficiency. Numerics suggest that the simplified model provides useful insight into behaviour of the full model. We then show examples based on microcolony formation in host domains and argue that internal heterogeneity can be related to community function.
The Maser-Starburst connection in NGC 253
Authors: Ellingsen Simon P.
Published: July 2018

NGC 253 is one of the closest starburst galaxies to the Milky Way and as such it has been studied in detail across the electromagnetic spectrum. Recent observations have detected the first extragalactic class I methanol masers at 36 and 44 GHz and the first extragalactic HC3N (cyanoacetylene) masers in this source. Here we discuss the location of the masers with respect to key morphological features within NGC 253 and the association between the masers and the ongoing starburst.
A detailed study toward the Water fountain IRAS 15445-5449
Authors: Pérez-Sánchez Andrés F. , López Rebeca García , Vlemmings Wouter , Tafoya Daniel
Published: July 2018

Post-Asymptotic giant branch (post-ABG) sources with high-velocity spectral features of H2O maser emission detected toward their circumstellar envelopes (CSEs) are known as Water Fountain (WF) nebulae. These are low- or intermediate-mass Galactic stellar sources that are undergoing the late stages of an intense mass-loss process. The velocity and the spatial distribution of the H2O maser spectral features can provide information about the kinematics of the molecular gas component of their CSEs. Hence, observational studies toward WF nebulae could help to better understand the formation of the asymmetric structures (hundred to thousand AUs) commonly seen toward Planetary nebulae (PNe). Here we present preliminary results of observations done toward the WF IRAS 15445-5449 using the Australia Telescope Compact Array (ATCA) and the Very Large Telescope (SINFONI/VLT). Assuming that the pumping of the H2O maser transitions is a consequence of shocks between different velocity winds, the spatial distribution of the emission shed light on the scales of the regions affected by the propagation of the shock-fronts.
SWAG Water Masers in the Galactic Center
Authors: Ott Jürgen , Krieger Nico , Rickert Matthew , Meier David , Ginsburg Adam , Yusef-Zadeh Farhad ,   the SWAG team
Published: July 2018

The Galactic Center contains large amounts of molecular and ionized gas as well as a plethora of energetic objects. Water masers are an extinction-insensitive probe for star formation and thus ideal for studies of star formation stages in this highly obscured region. With the Australia Telescope Compact Array, we observed 22 GHz water masers in the entire Central Molecular Zone with sub-parsec resolution as part of the large SWAG survey: “Survey of Water and Ammonia in the Galactic Center”. We detect of order 600 22 GHz masers with isotropic luminosities down to ~10−7 L⊙. Masers with luminosities of ≳10−6 L⊙ are likely associated with young stellar objects. They appear to be close to molecular gas streamers and may be due to star formation events that are triggered at pericenter passages near Sgr A*. Weaker masers are more widely distributed and frequently show double line features, a tell-tale sign for an origin in evolved star envelopes.
Periodic methanol masers and colliding wind binaries
Authors: van den Heever Stefanus P. , van der Walt D. J. , Pittard J. M. , Hoare M. G.
Published: July 2018

Since the discovery of periodic variability of Class II methanol masers associated with high-mass star formation, several possible driving mechanisms have been proposed to explain this phenomenon. Here the colliding wind binary (CWB) hypothesis is proposed to describe the periodic variability. It is shown that the recombination of a partially ionized gas describes the flare profiles remarkably well. In addition, the quiescent state flux density is also described remarkably well by the time-dependent change of the electron density. This suggests that the periodicity is caused by the time-dependent change in the radio free-free emission from the background HII regions against which the maser is projected.
Bow shocks in water fountain jets
Authors: Orosz Gabor , Gómez José F. , Tafoya Daniel , Imai Hiroshi , Torrelles José M. , Ngendo Ann Njeri , Burns Ross A.
Published: July 2018

We briefly introduce the VLBI maser astrometric analysis of IRAS 18043–2116 and IRAS 18113–2503, two remarkable and unusual water fountains with spectacular bipolar bow shocks in their high-speed collimated jet-driven outflows. The 22 GHz H2O maser structures and velocities clearly show that the jets are formed in very short-lived, episodic outbursts, which may indicate episodic accretion in an underlying binary system.
A systematic observational study of radio properties of H2O megamaser Seyfert 2s: A Guide for H2O megamaser surveys
Authors: Zhang J. S. , Liu Z. W. , Henkel C.
Published: July 2018

Analyzing archival data from different telescopes, H2O megamaser Seyfert 2s appeared to exhibit higher nuclear radio luminosities than non-masing Seyfert 2s (Zhang et al. 2012). This has been confirmed by our follow-up study on multi-band (11, 6, 3.6, 2, 1.3 cm) radio properties of maser host Seyfert 2s, through systematic Effelsberg observations (Liu et al. 2017). The nuclear radio luminosity was supposed to be a suitable indicator to guide future AGN maser searches. Thus we performed a pilot survey with the Effelsberg telescope on H2O maser emission toward a small sample of radio-bright Seyfert 2 galaxies with relatively higher redshift (>0.04). Our pilot survey led to one new megamaser source and one additional possible detection, which reflects our success in selecting H2O megamaser candidates compared to previous observations (higher detection rate, larger distance). Our successful selection technique choosing Seyfert 2s with radio-bright nuclei may provide good guiding for future H2O megamaser surveys. Therefore we are conducting a large systematic survey toward a big Seyfert 2 sample with such radio-bright nuclei. Detections of luminous H2O masers at large distance (z>0.04) may hold the great potential to increase our knowledge on the central highly obscured but still very enigmatic regions of active Seyfert galaxies (Zhang et al. 2017).
Filamentary Flows and Clump-fed High-mass Star Formation in G22
Authors: Yuan J. , Li J.-Z. , Wu Y.
Published: July 2018

G22 is a hub-filament system composed of four supercritical filaments. Velocity gradients are detected along three filaments. A total mass infall rate of 700 M⊙ Myr−1 would double the hub mass in about three free-fall times. The most massive clump C1 would be in global collapse with an infall velocity of 0.26 km s−1 and a mass infall rate of 5 × 10−4M⊙ yr−1, which is supported by the prevalent HCO+ (3-2) and 13CO (3-2) blue profiles. A hot molecular core (SMA1) was revealed in C1. At the SMA1 center, there is a massive protostar (MIR1) driving multipolar outflows which are associated with clusters of class I methanol masers. MIR1 may be still growing with an accretion rate of 7 × 10−5M⊙ yr−1. Filamentary flows, clump-scale collapse, core-scale accretion coexist in G22, suggesting that high-mass starless cores may not be prerequisite to form high-mass stars. In the high-mass star formation process, the central protostar, the core, and the clump can grow in mass simultaneously.
Methanol masers and magnetic field in IRAS18089-1732
Authors: Dall’Olio Daria , Vlemmings W. H. T. , Surcis G. , Beuther H. , Lankhaar B. , Persson M. V. , Richards A. M. S. , Varenius E.
Published: July 2018

Theoretical simulations have shown that magnetic fields play an important role in massive star formation: they can suppress fragmentation in the star forming cloud, enhance accretion via disc and regulate outflows and jets. However, models require specific magnetic configurations and need more observational constraints to properly test the impact of magnetic fields. We investigate the magnetic field structure of the massive protostar IRAS18089-1732, analysing 6.7 GHz CH3OH maser MERLIN observations. IRAS18089-1732 is a well studied high mass protostar, showing a hot core chemistry, an accretion disc and a bipolar outflow. An ordered magnetic field oriented around its disc has been detected from previous observations of polarised dust. This gives us the chance to investigate how the magnetic field at the small scale probed by masers relates to the large scale field probed by the dust.
A Masing Event in the Cat’s Paw
Authors: MacLeod G. , Smits D. , Goedhart S. , Ellingsen S. , Hunter T. , Brogan C.
Published: July 2018

We present Kitty, an unprecedented and near simultaneous flaring event in ten transitions (6 hydroxyl, 1 water and 3 methanol), that began on 1 January 2015 in the massive star-forming region NGC6334F located in the Cat’s Paw Nebula. The brightest components in each transition increased by factors of 20 to 70 in line with a factor of ~70 increase in dust emission luminosity for the source MM1. We also report the detection of only the fifth known 4.660 GHz hydroxyl maser and that it varied in a correlated fashion with 1.720, 6.031, and 6.035 GHz hydroxyl counterparts. We postulate that if Kitty, and two historical flares in 1965 & 1999, are accretion events and are caused by the successive passages of a secondary star disrupting the accretion disk, where the frequency of occurrence is cycling down at a rate of ~2.2, it is possible another event will occur in 2022.