bluuebunny/crossref_metadata_2025 huggingface dataset:
A computational study of the interaction of gaseous detonations with a compressible layer
Authors: Reynaud Maxime , Virot Florent , Chinnayya Ashwin
Published: May 2017

The propagation of two-dimensional cellular gaseous detonation bounded by an inert layer is examined via computational simulations. The analysis is based on the high-order integration of the reactive Euler equations with a one-step irreversible reaction. To assess whether the cellular instabilities have a significant influence on a detonation yielding confinement, we achieved numerical simulations for several mixtures from very stable to mildly unstable. The cell regularity was controlled through the value of the activation energy, while keeping constant the ideal Zel’dovich - von Neumann - Döring (ZND) half-reaction length. For stable detonations, the detonation velocity deficit and structure are in accordance with the generalized ZND model, which incorporates the losses due to the front curvature. The deviation with this laminar solution is clear as the activation energy is more significant, increasing the flow field complexity, the variations of the detonation velocity, and the transverse wave strength. The chemical length scale gets thicker, as well as the hydrodynamic thickness. The sonic location is delayed due to the presence of hydrodynamic fluctuations, for which the intensity is increased with the activation energy as well as with the losses to a lesser extent. The flow field has been studied through numerical soot foils, detonation velocities, and 2D detonation front profiles, which are consistent with experimental findings. The velocity deficit increases with the cell irregularity. Moreover, the relation between the detonation limits obtained numerically and in detonation experiments with losses is discussed.
Modelling and performance analysis of a silicon PV module
Authors: Abdullahi Nuruddeen , Saha Chitta , Jinks Robert
Published: May 2017

Significant effect and progress have been made by manufacturers and researchers to understand the performance and modelling concept of photovoltaic (PV) modules under various conditions such as wind, dust, and snow, which are often harsh and may lead to the degradation of PV modules. This paper presents a study on the performance of an 85 W monocrystalline photovoltaic module under different conditions, with measurements being taken under indoor and outdoor conditions. To obtain maximum irradiation under outdoor conditions, the module was inclined at an angle of 25° facing the southern direction (UK). To investigate the I-V characteristic of the PV module, a single diode electrical equivalent model has been developed using MATLAB-Simulink, and the measured results are discussed together with the simulation results. The measured results have shown that the module is capable of generating 17.75 W/m2 with an efficiency of 7% and 138 W/m2 with an efficiency of 8% from indoor office building and outdoor conditions, respectively, in UK during summer time. This research work makes a significant contribution to photovoltaic researchers to identify the suitable applications such as embedded devices or body-worn sensors for use both in indoor and outdoor conditions.
Perspective: Fabrication of integrated organ-on-a-chip via
bioprinting
Authors: Yang Qingzhen , Lian Qin , Xu Feng
Published: May 2017

Organ-on-a-chip has emerged as a powerful platform with widespread applications in biomedical engineering, such as pathology studies and drug screening. However, the fabrication of organ-on-a-chip is still a challenging task due to its complexity. For an integrated organ-on-a-chip, it may contain four key elements, i.e., a microfluidic chip, live cells/microtissues that are cultured in this chip, components for stimulus loading to mature the microtissues, and sensors for results readout. Recently, bioprinting has been used for fabricating organ-on-a-chip as it enables the printing of multiple materials, including biocompatible materials and even live cells in a programmable manner with a high spatial resolution. Besides, all four elements for organ-on-a-chip could be printed in a single continuous procedure on one printer; in other words, the fabrication process is assembly free. In this paper, we discuss the recent advances of organ-on-a-chip fabrication by bioprinting. Light is shed on the printing strategies, materials, and biocompatibility. In addition, some specific bioprinted organs-on-chips are analyzed in detail. Because the bioprinted organ-on-a-chip is still in its early stage, significant efforts are still needed. Thus, the challenges presented together with possible solutions and future trends are also discussed.
Multipurpose setup for low-temperature conversion electron Mössbauer spectroscopy
Authors: Augustyns V. , Trekels M. , Gunnlaugsson H. P. , Masenda H. , Temst K. , Vantomme A. , Pereira L. M. C.
Published: May 2017

We describe an experimental setup for conversion electron Mössbauer spectroscopy (CEMS) at low temperature. The setup is composed of a continuous flow cryostat (temperature range of 4.2-500 K), detector housing, three channel electron multipliers, and corresponding electronics. We demonstrate the capabilities of the setup with CEMS measurements performed on a sample consisting of a thin enriched 57Fe film, with a thickness of 20 nm, deposited on a silicon substrate. We also describe exchangeable adaptations (lid and sample holder) which extend the applicability of the setup to emission Mössbauer spectroscopy as well as measurements under an applied magnetic field.
A single-crystal model for the high-strain rate deformation of cyclotrimethylene trinitramine including phase transformations and plastic slip
Authors: Addessio F. L. , Luscher D. J. , Cawkwell M. J. , Ramos K. J.
Published: May 2017

A continuum model for the high-rate, thermo-mechanical deformation of single-crystal cyclotrimethylene trinitramine (RDX) is developed. The model includes the effects of anisotropy, large deformations, nonlinear thermo-elasticity, phase transformations, and plastic slip. A multiplicative decomposition of the deformation gradient is used. The volumetric elastic component of the deformation is accounted for through a free-energy based equation of state for the low- (α) and high-pressure (γ) polymorphs of RDX. Crystal plasticity is addressed using a phenomenological thermal activation model. The deformation gradient for the phase transformation is based on an approach that has been applied to martensitic transformations. Simulations were conducted and compared to high-rate, impact loading of oriented RDX single crystals. The simulations considered multiple orientations of the crystal relative to the direction of shock loading and multiple sample thicknesses. Thirteen slip systems, which were inferred from indentation and x-ray topography, were used to model the α-polymorph. It is shown that by increasing the number of slip systems from the previously considered number of six (6) to thirteen (13) in the α-polymorph, better comparisons with data may be obtained. Simulations of impact conditions in the vicinity of the α- to γ-polymorph transformation (3.8 GPa) are considered. Eleven of the simulations, which were at pressures below the transformation value (3.0 GPa), were compared to experimental data. Comparison of the model was also made with available data for one experiment above the transformation pressure (4.4 GPa). Also, simulations are provided for a nominal pressure of 7.5 GPa to demonstrate the effect of the transformation kinetics on the deformation of a high-rate plate impact problem.
Further insight on recombination losses in the intrinsic layer of a-Si:H solar cells using computer modeling tools
Authors: Rubinelli Francisco A. , Ramirez Helena , Ruiz Carlos M. , Schmidt Javier A.
Published: May 2017

Recombination losses of a-Si:H based p-i-n solar cells in the annealed state are analyzed with device computer modeling. Under AM1.5 illumination, the recombination rate in the intrinsic layer is shown to be controlled by a combination of losses through defect and tail states. The influence of the defect concentration on the characteristic parameters of a solar cell is analyzed. The impact on the light current-voltage characteristic curve of adopting very low free carrier mobilities and a high density of states at the band edge is explored under red and AM1.5 illumination. The distribution of trapped charge, electric field, and recombination loses inside the intrinsic layer is examined, and their influence on the solar cell performance is discussed. Solar cells with intrinsic layers deposited with and without hydrogen dilution are examined. It is found that the photocurrent at −2 V is not always a good approximation of the saturated reverse-bias photocurrent in a-Si:H p-i-n solar cells at room temperature. The importance of using realistic electrical parameters in solar cell simulations is emphasized.
Diffusion and aggregation process of oxygen embedded around an amorphous/crystal interface of Si(001) studied by molecular dynamics simulation
Authors: Hoshino Yasushi
Published: May 2017

I performed empirical molecular dynamics (MD) simulations to understand the peculiar migration behavior of oxygen embedded in an amorphous Si (a-Si) layer near the crystal/amorphous (c/a) Si interface and investigated the time evolution of the atomic configuration at high temperatures from 1200 to 1500 K. The previously proposed sweeping effect, which is demonstrated in terms of the oxygen migration and precipitation in silicon taking place along the moving c/a interface, was definitely confirmed in this MD simulation. [Hoshino et al., J. Phys. D: Appl. Phys. 49, 315106 (2016)] In the present study, I reproducibly found the theoretical evidence of the novel sweeping and aggregation phenomenon of oxygen occurring in the recrystallization process of a-Si. The temperature-dependence revealed that the relationship between the displacement velocity of the oxygen and the c/a interface plays an important role in interpreting the behavior. The oxide precipitations in the recrystallized Si as well as the sweeping effect were well reproduced in the simulation in which the systems containing several oxygen atoms were assumed. These facts significantly well explain and support my interpretation in the previous papers reported on the synthesis mechanism of the ultrathin silicon-on-insulator/buried oxide structure prepared by low-energy implantation followed by relatively low temperature annealing, compared to the ordinary separation by the implanted oxygen process.
Investigation of the interaction between competing types of nondiffusive transport in drift wave turbulence
Authors: Ogata D. , Newman D. E. , Sánchez R.
Published: May 2017

Radial transport in turbulence dominated tokamak plasmas has been observed to deviate from classical diffusion in certain regimes relevant for magnetic confinement fusion. These situations at least include near-marginal turbulence, where radial transport becomes superdiffusive and mediated by elongated radial structures (or avalanches) and transport across radially sheared poloidal flows, where radial subdiffusion often ensues. In this paper, the interaction between very different physical ingredients responsible for these two types of nondiffusive dynamics (namely, turbulent profile relaxation close to a local threshold and the interaction with radially sheared zonal flows) is studied in detail in the context of a simple two-dimensional electrostatic plasma fluid turbulence model based on the dissipative trapped electron mode. It is shown that, depending on the relative relevance of each of these ingredients, which can be tuned in various ways, a variety of non-diffusive radial transport behaviors can be found in the system. The results also illustrate the fact that the classical diffusion paradigm is often insufficient to describe turbulent transport in systems with self-generated flows and turbulent profile relaxations.
Length-dependent Seebeck effect in single-molecule junctions beyond linear response regime
Authors: Zimbovskaya Natalya A.
Published: May 2017

In the present work, we theoretically study characteristics of the nonlinear Seebeck effect in a single-molecule junction with chain-like bridge of an arbitrary length. We have employed tight-binding models to compute the electron transmission through the system. We concentrate on the analysis of dependences of thermovoltage Vth and differential thermopower S on the bridge length. It is shown that Vth becomes stronger and S grows as the bridge lengthens. We discuss the effects of the bridge coupling to the electrodes and of specific characteristics of terminal sites on the bridge on the length-dependent Vth and S, which appear when the system operates beyond the linear response regime.
Mapping magnetoelastic response of terfenol-D ring structure
Authors: Youssef George , Newacheck Scott , Lopez Mario
Published: May 2017

The magneto-elastic response of a Terfenol-D (Tb.3Dy.7Fe1.92) ring has been experimentally investigated and analyzed. Ring structures give rise to complex behavior based on the interaction of the magnetic field with the material, which is further compounded with anisotropies associated with mechanical and magnetic properties. Discrete strain measurements were used to construct magnetostriction maps, which are used to elucidate the non-uniformity of the strain distribution due to geometrical factors and magnetic field interactions, namely, magnetic shielding and stable onion state in the ring structure.
Dynamic nuclear polarization enhanced magnetic field sensitivity and decoherence spectroscopy of an ensemble of near-surface nitrogen-vacancy centers in diamond
Authors: Sasaki Kento , Kleinsasser Ed E. , Zhu Zhouyang , Li Wen-Di , Watanabe Hideyuki , Fu Kai-Mei C. , Itoh Kohei M. , Abe Eisuke
Published: May 2017

We perform pulsed optically detected electron spin resonance to measure the DC magnetic field sensitivity and electronic spin coherence time T2 of an ensemble of near-surface, high-density nitrogen-vacancy centers engineered to have a narrow magnetic resonance linewidth. Combining pulsed spectroscopy with dynamic nuclear polarization, we obtain the photon-shot-noise-limited DC magnetic sensitivity of 35 nT Hz−0.5. We find that T2 is controlled by instantaneous diffusion, enabling decoherence spectroscopy on residual nitrogen impurity spins in the diamond lattice and a quantitative determination of their density. The demonstrated high DC magnetic sensitivity and decoherence spectroscopy are expected to broaden the application range for two-dimensional magnetic imaging.
Magnetocaloric effect and influence of Fe/Cr disorder on the magnetization reversal and dielectric relaxation in RFe0.5Cr0.5O3 systems
Authors: Yin L. H. , Yang J. , Tong P. , Luo X. , Song W. H. , Dai J. M. , Zhu X. B. , Sun Y. P.
Published: May 2017

We have investigated the structural, magnetic, and dielectric properties of RFe0.5Cr0.5O3 (R = Nd, Sm, Gd, and Y) compounds. Both structure and magnetic analyses show a Fe/Cr cation disorder, which results in the existence of Fe-rich and Cr-rich clusters. The competition between the moments of the two clusters gives rise to the R-dependent temperature induced magnetization reversal. Interestingly, we also find that the charge carrier hopping in the two clusters leads to two sequential dielectric relaxations in all the samples. In addition, giant magnetocaloric effect with a magnetic entropy change reaching ∼29.2 J/kg K was observed with R = Gd.
Influence of TMAl preflow on AlN epitaxy on sapphire
Authors: Sun Haiding , Wu Feng , Park Young Jae , Al tahtamouni T. M. , Li Kuang-Hui , Alfaraj Nasir , Detchprohm Theeradetch , Dupuis Russell D. , Li Xiaohang
Published: May 2017

The trimethylaluminum (TMAl) preflow process has been widely applied on sapphire substrates prior to growing Al-polar AlN films by metalorganic chemical vapor deposition. However, it has been unclear how the TMAl preflow process really works. In this letter, we reported on carbon's significance in the polarity and growth mode of AlN films due to the TMAl preflow. Without the preflow, no trace of carbon was found at the AlN/sapphire interface and the films possessed mixed Al- and N-polarity. With the 5 s preflow, carbon started to precipitate due to the decomposition of TMAl, forming scattered carbon-rich clusters which were graphitic carbon. It was discovered that the carbon attracted surrounding oxygen impurity atoms and consequently suppressed the formation of AlxOyNz and thus N-polarity. With the 40 s preflow, the significant presence of carbon clusters at the AlN/sapphire interface was observed. While still attracting oxygen and preventing the N-polarity, the carbon clusters served as randomly distributed masks to further induce a 3D growth mode for the AlN growth. The corresponding epitaxial growth mode change is discussed.
The effect of hydraulic-fracture parameters on the welltest response of multi-fractured tight-gas reservoirs
Authors: Qiu Chaolang , Hossain Mofazzal , Bahrami Hassan , Lu Yangfan
Published: May 2017

With the reduction of conventional reserves, the demand and exploration of unconventional sources becomes increasingly important in the energy supply system. Low permeability, low porosity, and the complexities of rock formation in unconventional gas reservoirs make it difficult to extract commercially viable gas resources. Hydraulic fracture is the most common technique used for commercial production of hydrocarbon resources from unconventional tight-gas reservoirs. Due to the existence of an extremely long transient-flow period in tight-gas reservoirs, the interpretation of welltest data based on conventional welltest analysis is quite challenging, and could potentially lead to misleading results.
This peer-reviewed paper presents a new approach based on a log-log reciprocal rate derivative plot. Emphases are given on the identification of factors affecting the welltest response in multiple hydraulic-fractured wells in unconventional gas reservoirs based on numerical simulation. The objective is to investigate the sensitivity of various reservoir and hydraulic-fracture parameters, such as multiple hydraulic-fracture size, fracture number and fracture orientation on welltest response, and the effect of the pressure derivative curve on the slopes of welltest diagnostic plots, as well as on well productivity performance. The results can be used to understand the welltest response for different hydraulic-fracturing scenarios for the efficiency and characteristics of hydraulic fractures.
Altered interactions between unicellular and multicellular genes drive hallmarks of transformation in a diverse range of solid tumors
Authors: Trigos Anna S. , Pearson Richard B. , Papenfuss Anthony T. , Goode David L.
Published: May 2017

Significance

Cancer represents a breakdown of molecular mechanisms evolved by multicellular life to impose constraints on cell growth, resulting in more “primitive” proliferative cellular phenotypes. This suggests interpreting the activity of genes in cancer according to their evolutionary origins may provide insights into common mechanisms driving tumorigenesis. We incorporated phylogenetic and interaction data into expression analysis of seven solid tumors, revealing universal strong preferential expression of genes shared with unicellular species in tumors, alongside widespread disruption of links between unicellular and multicellular components of gene regulatory networks. Considering how the constraints imposed on these networks by evolution were altered in tumors identified molecular processes that could be manipulated for therapeutic benefit in cancer and uncovered several promising drug targets.
Enhanced CO
2
uptake at a shallow Arctic Ocean seep field overwhelms the positive warming potential of emitted methane
Authors: Pohlman John W. , Greinert Jens , Ruppel Carolyn , Silyakova Anna , Vielstädte Lisa , Casso Michael , Mienert Jürgen , Bünz Stefan
Published: May 2017

Significance

Methane released from the seafloor and transported to the atmosphere has the potential to amplify global warming. At an arctic site characterized by high methane flux from the seafloor, we measured methane and carbon dioxide (CO
2
) exchange across the sea−air interface. We found that CO
2
uptake in an area of elevated methane efflux was enhanced relative to surrounding waters, such that the negative radiative forcing effect (cooling) resulting from CO
2
uptake overwhelmed the positive radiative forcing effect (warming) supported by methane output. Our work suggests physical mechanisms (e.g., upwelling) that transport methane to the surface may also transport nutrient-enriched water that supports enhanced primary production and CO
2
drawdown. These areas of methane seepage may be net greenhouse gas sinks.
Mechanism of duplex DNA destabilization by RNA-guided Cas9 nuclease during target interrogation
Authors: Mekler Vladimir , Minakhin Leonid , Severinov Konstantin
Published: May 2017

Significance

The prokaryotic clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas) systems have been widely used as tools for various genome-engineering applications. The most popular CRISPR-Cas system makes use of the Cas9 endonuclease from
Streptococcus pyogenes
(SpCas9) and a single-guide RNA (sgRNA). The SpCas9/sgRNA complex cleaves double-stranded DNA sequences specified by sgRNA and protospacer adjacent motif (PAM). This study explores the mechanism by which SpCas9/sgRNA efficiently locates the correct target DNA sequence. The results show that high efficiency of DNA interrogation can be explained, in part, by destabilization of double-stranded DNA conformation in the vicinity of PAM. The data also suggest that the local DNA destabilization is mediated by SpCas9/sgRNA affinity for a single-stranded DNA segment adjacent to PAM and by hindering of duplex DNA entry into the SpCas9/sgRNA interior.
Chromosome-level genome assembly and transcriptome of the green algaChromochloris zofingiensisilluminates astaxanthin production
Authors: Roth Melissa S. , Cokus Shawn J. , Gallaher Sean D. , Walter Andreas , Lopez David , Erickson Erika , Endelman Benjamin , Westcott Daniel , Larabell Carolyn A. , Merchant Sabeeha S. , Pellegrini Matteo , Niyogi Krishna K.
Published: May 2017

Significance

The growing human population generates increasing demand for food and energy. Microalgae are a promising source of sustainable bioproducts whose production may not exacerbate worsening environmental problems. The green algaChromochloris zofingiensishas potential as a biofuel feedstock and source of high-value nutraceutical molecules, including the carotenoid astaxanthin. We present a high-quality, chromosome-level assembly of the genome by using a hybrid sequencing approach with independent validation by optical mapping. Our analyses of the genome and transcriptome, in addition to experiments characterizing astaxanthin production, advance understanding of the green lineage and carotenoid production, and enhance prospects for improving commercial production ofC. zofingiensis.
Streptococcus pneumoniae
capsular polysaccharide is linked to peptidoglycan via a direct glycosidic bond to β-D-
N
-acetylglucosamine
Authors: Larson Thomas R. , Yother Janet
Published: May 2017

Significance

Bacterial surface polysaccharides form the interface between the bacterium and its environment. In Gram-positive bacteria, the intricate architecture of the peptidoglycan (PG) serves as the scaffolding to which other surface polysaccharides, including capsules, can be anchored. For pathogenic bacteria, proper localization of capsular polysaccharide (CPS) is essential to cause disease. In
Streptococcus pneumoniae
, CPS is also the primary target for vaccines. Here, we identify a structure for polysaccharide attachment to PG that involves a direct glycosidic linkage. Knowledge of this linkage lays the groundwork for identifying the enzyme(s) involved in its synthesis and for developing new targets for therapeutic interventions.
mTORC1 promotes proliferation of immature Schwann cells and myelin growth of differentiated Schwann cells
Authors: Beirowski Bogdan , Wong Keit Men , Babetto Elisabetta , Milbrandt Jeffrey
Published: May 2017

Significance

The myelination of axons is essential for neuronal wiring and normal nervous system functions. In the peripheral nervous system, Schwann cells (SCs) form myelin sheaths around axons during nerve development. Such myelination is compromised in a number of diseases. Hence, identification and understanding of the key pathways regulating SC development and myelinogenesis are essential for therapeutic progress. Here we uncover two separate roles of the cellular signaling node mTORC1 (mechanistic target of rapamycin complex 1) for regulating the development of SCs and subsequently the growth of myelin sheaths. Moreover, we demonstrate that defective SCs possess a remarkable plasticity to remyelinate axons via mTORC1. Thus, manipulating mTORC1 activity in diseased SCs could be therapeutically beneficial.
Expressing conditionality in Mandarin
Authors: Chen Weiying , Evers-Vermeul Jacqueline
Published: May 2017

After a broad overview of Mandarin Chinese conditionality marking, this paper presents a corpus-based analysis of two conditional connectives,rúguǒandzhǐyào(both translatable as ‘if’), from a syntactic and a cognitive perspective. We examine their use in narrative and informative texts along four parameters: clause order, position of the connective within the clause, domain, and counterfactuality. For all parameters, the two connectives displayed robust profiles across genres. Both connectives preferred an antecedent-consequent clause order. They displayed flexibility in their position, behaving like adverbs, withrúguǒshowing a stronger preference for the pre-subject position thanzhǐyào. In terms of domains,zhǐyàohas a stronger preference for content conditionals thanrúguǒ, which is also frequently used in the epistemic domain. In our data, onlyrúguǒwas used meta-metaphorically and in counterfactuals. We argue that both connectives can be translated with ‘if’. Butzhǐyàoalso matches ‘so/as long as’.
Advanced and intermediate EFL learners’ perceptions and practices of autonomous learning
Authors: Jafari Sakineh , Ketabi Saeed , Tavakoli Mansoor
Published: May 2017

This study examined Persian intermediate and advanced EFL learners’ perceptions regarding (a) their own and their teachers’ responsibility in learning language autonomously; (b) their decision making ability in learning language autonomously; and (c) their autonomous learning activities inside and outside the classroom. To this end, a questionnaire designed by Chan, Spratt, and Humphrey (2002) was distributed among 67 intermediate and 65 advanced EFL learners. Statistical analysis of students’ answers showed that overall, advanced learners tended to assume more responsibility for their own learning, to perceive themselves to be highly capable of autonomous learning, and to practice more autonomous learning activities compared to the intermediate learners. In addition, data collected through the interviews with some of the participants suggested that learners’ perceptions were greatly affected by their previous educational experiences. Since intermediate learners were not largely engaged in making decisions related to educational materials and activities used in their classrooms, they considered themselves as less responsible for and consequently less capable of choosing learning materials and activities. The findings of the study, along with the pedagogical implications, are discussed.
The space for strategic manoeuvring in adjudicating a freedom of speech case in the Netherlands
Authors: Jansen Henrike
Published: May 2017

In this article it is shown that the institutional preconditions of the activity type adjudicating a freedom of speech case leave much room for strategic manoeuvring with topical selection. To this end, an analysis is presented of the argumentation of the District Court in a case against the Dutch anti-immigration politician Geert Wilders. In order to show the space for manoeuvring, this argumentation, resulting in acquittal, is compared with the argumentation put forward by the Court of Appeal, which had ordered, after the Public Prosecution Service’s refusal to do so, that Wilders be prosecuted. The analysis shows that the District Court made ample use of the space for manoeuvring provided at the normative level concerning the interpretation of legal rules and case law, and the space provided at the factual level of classifying the contested facts in light of the previously identified meaning of a rule.
Do adult-children dialogical interactions leave space for a full development of argumentation?
Authors: Greco Sara , Mehmeti Teuta , Perret-Clermont Anne-Nelly
Published: May 2017

This paper sets out to analyse a case study of adult-children interaction in an educational context from a perspective of argumentation. We select a case in which 3 argumentative discussions are opened and we analyse them with the aim of understanding whether they are fully developed from a point of view of argumentation; or whether they are cut short and why. Our focus is not on the children’s individual productions but on the process of interaction. We assume the pragma-dialectical model of argumentation and the AMT as a theoretical framework. Our findings show that none of the discussions opened gets to a concluding stage, either because the teacher shifts the discussion on a different issue, or because the opening stage is not clear, or because the argumentation stage is not adequately developed. These findings contribute to conceptual clarification about how to interpret the role of a teacher.
Competition and conflict between communicative norms
Authors: Hoppmann Michael
Published: May 2017

When engaging with each other, discussants navigate a complex set of communicative norms that aim at very different goals. Within argumentation theory naturally the most studied set of norms are those aiming at reasonableness, of which I take the pragma-dialectical rule set to be a representative example. They are however far from the only norms that guide communicative behavior. This paper offers an analysis of the areas of intersection and potential conflict of reasonableness (as understood by pragma-dialectics) with other communicative norms in general and rules of politeness (as presented by Geoffrey Leech) in particular.
The case for alveolar fricative rhotics with evidence from Nusu
Authors: Ikeda Elissa , Lew Sigrid
Published: May 2017

Cross-linguistically, fricatives are the rarest types of rhotics, found in a few African and European languages (Ladefoged & Maddieson 1996) and as allophones in some Romance languages (Jesus & Shadle 2005;Recasens 2002;Bradley 2006;Colantoni 2006). Acoustic data from Nusu, phonotactic reasoning, and a cognate comparison demonstrate the presence of alveolar fricative rhotics in Tibeto-Burman. The Nusu rhotic appears in syllable-initial position as the first or second consonant and can be realized as alveolar approximants [ɹ] or [ɹʲ], non-sibilant voiced and voiceless fricatives [ɹ̝, ɹ̥], as well as voiced sibilant [ʐ]. In other studies on Nusu, these fricative rhotics have sometimes been reported as retroflex voiced sibilants (Sun & Lu 1986;Fu 1991), but intra-speaker and cross-variety comparison point to classification as rhotics. Evidence from other Tibeto-Burman languages suggests that alveolar fricative rhotics are not limited to Nusu. Together these data challenge the tradition of generally interpreting alveolar fricatives as sibilants.
Kiranti double negation
Authors: van der Auwera Johan , Vossen Frens
Published: May 2017

It is shown how Kiranti languages often express a semantically single clausal negation of a declarative verbal main clause with two clausal negators. We conjecture that the second negator has its origin in a copula and that the reinterpretation and integration of the copula into a negative construction follows the scenario known as a “Jespersen Cycle”.
On the origin of Gamale Kham labial-palatal approximants
Authors: Wilde Christopher P.
Published: May 2017

The development of the Gamale Kham labial-palatal approximants /ɥ/ and /ɥ̊/ has previously been attributed to the loss of the Proto-Kham initial *p- or the coda *-p. The vowels /i/ and /e/ which occurred in the adjacent syllable nucleus were rounded, resulting in the front rounded vowels /y/ and /ø/. Following this development, /w/ and /j/ merged to /ɥ/ in Gamale and Eastern Parbate Kham (Watters 2002;2004;2005). This study evaluates this theory and suggests two alternative explanations: that Proto-Kham may have had either two front rounded vowels *y and *ø, or a *ɥ phoneme. In the second case, the work refers to a possible correspondence between a Proto-Kham *ɥ and the Proto-Tibeto-Burman complex *jw.
Factors Influencing Nest Survival in Florida Bass
Authors: Slagle Z. , Allen M. S. , Shaw S. L.
Published: May 2017

Angling nesting Florida Bass Micropterus salmoides floridanus may influence the survival of the brood and could negatively affect bass populations. Our objectives were to estimate daily nest survival for Florida Bass and to examine factors that influence nest survival to the swim‐up fry stage. Snorkelers examined a total of 259 nests in a small, mesotrophic lake in north‐central Florida from 2010 to 2012. We compared nest survival rates with accumulated degree‐days, largest temperature drop following nest discovery, nest score, presence of a guarding male bass, and size of the guarding male. The most important factor in determining nest survival was the presence of a male bass. However, guarding male fish were only observed on 66% of active nests despite multiple visits to each nest, indicating a lower tendency to remain with the brood than has been reported in other Micropterus species. Florida Bass have displayed lower nest guarding behaviors in other studies; a prolonged spawning season and the presence of top predators in southern bass populations may influence decreased nest fidelity and nest guarding behavior. Individual nesting attempts may be less important for successful Florida Bass recruitment.

Received September 28, 2016; accepted February 28, 2017 Published online May 12, 2017
Purification and characterization of hemolysin from periodontopathogenic bacterium Eikenella corrodens strain 1073
Authors: Jasin Mansur Fariha , Takahara Sari , Yamamoto Mihoko , Shimatani Masafumi , Minnatul Karim Mohammad , Noiri Yuichiro , Ebisu Shigeyuki , Azakami Hiroyuki
Published: May 2017

Eikenella corrodens 1073 was found to show hemolytic activity when grown on sheep blood agar. A high and dose-dependent hemolytic activity was detected in the cell envelope fraction, which was further purified by ion-exchange and gel-filtration chromatography. Consequently, a 65-kDa protein with hemolytic activity was obtained, suggesting that this protein might be a hemolysin. Its N-terminal amino acid sequence was nearly identical to that of X-prolyl aminopeptidase from E. corrodens ATCC 23834. To confirm that X-prolyl aminopeptidase functions as a hemolytic factor, we expressed the hlyA gene, encoding X-prolyl aminopeptidase, in Escherichia coli. After induction with isopropyl β-D-1-thiogalactopyranoside, a protein of about 65 kDa was purified on a Ni column, and its hemolytic activity was confirmed. Meanwhile, a strain with a disrupted hlyA gene, which was constructed by homologous recombination, did not show any hemolytic activity. These results suggested that X-prolyl aminopeptidase might function as a hemolysin in E. corrodens.
The chromokinesin Klp3a and microtubules facilitate acentric chromosome segregation
Authors: Karg Travis , Elting Mary Williard , Vicars Hannah , Dumont Sophie , Sullivan William
Published: May 2017

Although poleward segregation of acentric chromosomes is well documented, the underlying mechanisms remain poorly understood. Here, we demonstrate that microtubules play a key role in poleward movement of acentric chromosome fragments generated in Drosophila melanogaster neuroblasts. Acentrics segregate with either telomeres leading or lagging in equal frequency and are preferentially associated with peripheral bundled microtubules. In addition, laser ablation studies demonstrate that segregating acentrics are mechanically associated with microtubules. Finally, we show that successful acentric segregation requires the chromokinesin Klp3a. Reduced Klp3a function results in disorganized interpolar microtubules and shortened spindles. Normally, acentric poleward segregation occurs at the periphery of the spindle in association with interpolar microtubules. In klp3a mutants, acentrics fail to localize and segregate along the peripheral interpolar microtubules and are abnormally positioned in the spindle interior. These studies demonstrate an unsuspected role for interpolar microtubules in driving acentric segregation.
UPR transducer BBF2H7 allows export of type II collagen in a cargo- and developmental stage–specific manner
Authors: Ishikawa Tokiro , Toyama Takuya , Nakamura Yuki , Tamada Kentaro , Shimizu Hitomi , Ninagawa Satoshi , Okada Tetsuya , Kamei Yasuhiro , Ishikawa-Fujiwara Tomoko , Todo Takeshi , Aoyama Eriko , Takigawa Masaharu , Harada Akihiro , Mori Kazutoshi
Published: May 2017

The unfolded protein response (UPR) handles unfolded/misfolded proteins accumulated in the endoplasmic reticulum (ER). However, it is unclear how vertebrates correctly use the total of ten UPR transducers. We have found that ER stress occurs physiologically during early embryonic development in medaka fish and that the smooth alignment of notochord cells requires ATF6 as a UPR transducer, which induces ER chaperones for folding of type VIII (short-chain) collagen. After secretion of hedgehog for tissue patterning, notochord cells differentiate into sheath cells, which synthesize type II collagen. In this study, we show that this vacuolization step requires both ATF6 and BBF2H7 as UPR transducers and that BBF2H7 regulates a complete set of genes (Sec23/24/13/31, Tango1, Sedlin, and KLHL12) essential for the enlargement of COPII vesicles to accommodate long-chain collagen for export, leading to the formation of the perinotochordal basement membrane. Thus, the most appropriate UPR transducer is activated to cope with the differing physiological ER stresses of different content types depending on developmental stage.
Final report on the EURAMET.M.FF-K4.2.2014 volume comparison at 100 μL—calibration of micropipettes
Authors: Batista Elsa , Matus Michael , Metaxiotou Zoe , Tudor Maria , Lenard Elzbieta , Buker Oliver , Wennergren Per , Piluri Erinda , Miteva Mariana , Vicarova Martina , Vospĕlová Alena , Turnsek Urska , Micic Ljiljana , Grue Lise-Lote , Mihailovic Mirjana , Sarevska Anastazija
Published: May 2017

During the EURAMET TC-F meeting of 2014 and following the finalization of CCM.FF-K4.2.2011 comparison, it was agreed to start a Regional Key Comparison (KC) on volume measurements using two 100 μL micropipettes (piston pipettes) allowing the participating laboratories to assess the agreement of their results and uncertainties.

Two 100 μL micropipettes were tested by 15 participants. One participant was not a member or associate member of the BIPM and was be removed from this report. The comparison started in July 2015 and ended in March 2016. The Volume and Flow Laboratory of the Portuguese Institute for Quality (IPQ) was the pilot laboratory and performed the initial and final measurements of the micropipettes. The micropipettes showed a stable volume during the whole comparison, which was confirmed by the results from the pilot laboratory.

The original results of all participant NMIs were corrected to the standard atmospheric pressure in order to compare results under the same calibration conditions, and the contribution of the 'process-related handling contribution' was added to the uncertainty budget of each participant.

In general the declared CMCs are in accordance with the KCDB. For the micropipette 354828Z, two laboratories had inconsistent results. For micropipette 354853Z, three laboratories had inconsistent results.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
The Effects of Tomato Suspension Agreements on Market Price Dynamics and Farm Revenue
Authors: Wu Feng , Guan Zhengfei , Suh Dong Hee
Published: May 2017

Since 1996 there have been several suspension agreements between the United States and Mexico that set reference prices for imported Mexican tomatoes. The 2013 suspension agreement raised the reference prices of Mexican tomatoes by 43%. This study conducts an econometric analysis to examine the effects of reference prices on the dynamics of tomato price and farm revenue. Findings indicate that the suspension agreements have resulted in significant adjustments in the U.S. and Mexican tomato prices, and that the two prices are now more interdependent under the 2013 agreement. Although the 2013 suspension agreement has boosted the prices of U.S. tomatoes, simulation analysis shows that the Mexican industry reaps most of the benefits from increased prices under the 2013 suspension agreement. The findings in this study could inform future trade negotiations.
Charters and Inter-Urban Networks: England, 1439–1449
Authors: Hartrich Eliza
Published: May 2017

Royal charters to towns—once the bedrock of medieval urban history—have received little attention in recent years from historians of urban politics in late medieval England. This paper seeks to rehabilitate the role of the royal charter in urban history by proposing that it represents not merely the relationship between individual civic governments and the Crown, but also the less formal and often otherwise unrecoverable interpersonal networks between politically important townspeople. Periods when a large number of towns requested the same types of liberties from the Crown were not usually the result of royal policy or local circumstance, but instead of frequent communication between elite merchants of different towns that took place in parliament or through trans-regional mercantile organisations. In studying patterns of charter acquisition by towns, therefore, it becomes possible to identify an inter-urban network in medieval English politics, to chart its membership, and to observe the fluctuating nature of its influence over time. By recognising that charters—documents frequently seen as pillars of urban autonomy and political isolationism—actually stem from a world of inter-urban networks with a high level of engagement in national politics, we can also begin to appreciate that politics in fifteenth-century England was not the sole preserve of magnate affinities but was also responsive to the interests and activities of an interconnected urban political lobby.
Contributions of adult mortality to declines of Puget Sound Pacific herring
Authors: Siple Margaret C , Shelton Andrew O , Francis Tessa B , Lowry Dayv , Lindquist Adam P , Essington Timothy E
Published: May 2017

Forage fish undergo dramatic changes in abundance through time. Long-term fluctuations, which have historically been attributed to changes in recruitment, may also be due to changes in adult mortality. Pacific herring, a lightly exploited forage fish in Puget Sound, WA, have exhibited shifts in age structure and decreases in spawning biomass during the past 30 years. Here, we investigate changes in adult mortality as a potential explanation for these shifts. Using a hierarchical, age-structured population model, we indicate that adult natural mortality for Puget Sound Pacific herring has increased since 1973. We find that natural mortality has increased for every age class of adult (age 3+), especially age 4 fish, whose estimated mortality has doubled over the survey time period (from M = 0.84–1.76). We demonstrate that long-term shifts in mortality explain changes in age structure, and may explain biomass declines and failure to reach management thresholds for two spawning sites in Puget Sound (Cherry Point and Squaxin Pass). Temporal shifts in natural adult mortality could have negative implications for herring and herring predators. We demonstrate that adult mortality, in addition to recruitment variation, is an important driver for forage fish, which face exceptionally high natural mortality compared with other fishes.
Radiographic and Neurological Outcome After Surgical Treatment of Traumatic Fractures of the Ankylotic Thoracic Spine: A Retrospective Case Series
Authors: Dru Alexander B , Kubilis Paul S , Murad Gregory A , Carney Tyler , Hoh Daniel J
Published: May 2017

BACKGROUND

Spontaneous thoracic ankylosis is a progressive degenerative process that predisposes patients to potentially highly unstable traumatic injuries. Acute hyperextension fractures result in dynamic instability putting the spinal cord at risk.

OBJECTIVE

To describe preoperative radiographic characteristics of fractures of the ankylotic thoracic spine and relate findings to early postoperative radiographic and clinical outcomes.

METHODS

A single center, retrospective review was performed of 28 surgically treated patients with fractures of the ankylotic thoracic spine. Radiographic assessment included preoperative fracture angulation (FA) and fracture displacement (FD), and postoperative change in sagittal alignment. Early clinical outcomes included preoperative and postoperative American Spinal Injury Association (ASIA) grade and perioperative complications.

RESULTS

Seven patients (25%) presented with poor neurological grade (ASIA A-C) compared to 21 (75%) with good grade (ASIA D, E). At presentation, poor grade patients had a mean FA of 16.4° (range 0°-34.5°), and FD of 7.76 mm (range 0.8-9.2). Good grade patients had a mean FA of 18.2° (range 0°-43.3°), and FD of 4.77 mm (range 0-25.1). There was no statistically significant difference in FA or FD between groups (P = .70 and .20 respectively). All underwent posterior pedicle screw fixation for stabilization. Fifty per cent of patients presenting with ASIA C or D spinal cord injury improved 1 or more ASIA grades. There were no perioperative complications. Early postoperative sagittal alignment was maintained with a mean change of –2.6°.

CONCLUSION

Presenting fracture alignment does not significantly correlate with pre- or postoperative neurological status. Early posterior stabilization preserved neurological function, with neurological recovery occurring in a portion of individuals.