bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of dissolved organic matter (DOM) source on copper speciation and toxicity to Brachionus plicatilis
Authors: Tait Tara N. , Cooper Christopher A. , McGeer James C. , Wood Chris M. , Smith D. Scott
Published: February 2016

Environmental context
Organic matter dissolved in water can mitigate toxic effects of copper, which should be taken into account when estimating risks of copper pollution. The composition of this organic matter, however, can vary widely, and these variations might also need to be taken into account. This work addresses the question of organic matter quality and demonstrates that only the amount and not the source influences copper toxicity – good news for risk analysis because it simplifies predictions of the effects of copper in specific receiving waters.

Abstract
The toxicity of copper in marine systems is dependent on its speciation and bioavailability. Dissolved organic matter (DOM) can complex copper, resulting in decreased bioavailability and hence decreased toxicity. The purpose of this study was to measure acute copper LC50 values (concentration lethal to 50% of the organisms) in natural marine waters in a sensitive organism, and identify the relationships between DOM quality and copper toxicity and speciation. Static acute copper toxicity tests (48-h LC50) were performed using the euryhaline rotifer Brachionus plicatilis. Ion-selective electrode measurements of free copper were performed at the LC50 concentrations to determine the influence of DOM source on copper speciation. LC50 values ranged from 333 to 980nM (21.1 to 62.3µgL–1) with DOC concentrations ranging from 0.55 to 7.57mgCL–1. DOC was found to be protective (R2 = 0.72, P = 0.016); however, the degree of protection decreased as DOC increased. This suggests salt-induced colloid formation could be occurring, resulting in a decrease of binding sites available to complex free copper. Free copper remained fairly constant between each sample site, with an average pCu of 10.14. Overall, this study is consistent with other studies that suggest free copper is the best species for predicting toxicity. Additionally, no significant correlation between DOM source and copper toxicity was observed as compared with total DOC concentration and copper toxicity, suggesting that DOM quality does not need to be taken into account for copper toxicity modelling in salt water.
Parameter-sparse modification of Fourier methods to analyse the shape of closed contours with application to otolith outlines
Authors: Harbitz Alf
Published: February 2016

Elliptical Fourier descriptors (EFDs) have been used extensively in shape analysis of closed contours and have a range of marine applications, such as automatic identification of fish species and discrimination between fish stocks based on EFDs of otolith contours. A recent method (the ‘MIRR’ method) transforms the two-dimensional contour to a one-dimensional function by mirroring (reflecting) the lower half of the contour around a vertical axis at the right end of the contour. MIRR then applies the fast Fourier transform (FFT) to the vertical contour points corresponding to equidistant coordinate values along the horizontal axis. MIRR has the advantage of reducing the number of Fourier coefficients to two coefficients per frequency component compared with four EFDs. However, both Fourier methods require several frequency components to reproduce a pure ellipse properly. This paper shows how the methods can be easily modified so that a virtually perfect reproduction of a pure ellipse is obtained with only one frequency component. In addition, real otolith examples for cod (Gadus morhua) and Greenland halibut (Reinhardtius hippoglossoides) are used to demonstrate that the modified methods give better approximations to the large-scale shape of the original contour with fewer coefficients than the traditional Fourier methods, with negligible additional computing time.
Hazardous Alcohol use and Cultural Adjustment among U.S. College Students Abroad in Italy: Findings and Recommendations for Study Abroad Staff and Researchers
Authors: Mitchell Michael A. , Poyrazli Senel , Broyles Lauren Matukaitis
Published: February 2016

Background

Italy is a top destination for U.S. college students studying abroad. Both international and local Italian media outlets, such as city newspapers, have cited the discordance between Italian cultural norms and U.S. college students’ drinking behaviors. Hazardous alcohol consumption abroad, such as binge drinking, can result in individual- (e.g., physical injury) and social- (e.g., promotion of negative stereotypes) level adverse consequences.

Methods

We assessed the prevalence of hazardous alcohol use and recent binge drinking in a sample of U.S. college students studying abroad in Italy ( n = 111). We evaluated associations among drinking and cultural adjustment and determined which sociocultural factors predicted binge drinking for students abroad.

Results

Forty-six percent of students were classified as hazardous drinkers and 63% reported recent binge drinking. Socializing with American peers was a significant predictor for binge drinking abroad.

Conclusions

Binge drinking was quite prevalent in our sample of students studying abroad in Italy. Study abroad advisors, instructors, and staff should consider diverse strategies to screen, educate, prevent, and/or intervene on alcohol misuse with their students. These strategies should be personalized to both the student as well as the host culture's norms.
Predictors of Higher-Risk Chronic Opioid Prescriptions in An Academic Primary Care Setting
Authors: Bauer Scott R. , Hitchner Lily , Harrison Hannah , Gerstenberger John , Steiger Scott
Published: February 2016

Background

Patients with chronic noncancer pain treated with higher doses of opioids or concurrent substance use are at increased risk of adverse events. Although several national guidelines recommend maximum dosing thresholds and urine drug testing, adherence to these guidelines is inconsistent.

Methods

To identify predictors of higher-risk opioid prescriptions in 2 academic primary care clinics, the authors developed a retrospective cohort of 842 patients who were prescribed ≥5 opioid prescriptions for noncancer pain between March 2012 and March 2013. The authors evaluated odds of higher-dose opioid prescriptions and urine drug testing using multivariate logistic models.

Results

Among study subjects, 47% received prescriptions for the equivalent of ≥50 mg morphine per day. After adjustment for confounders, patients with a resident primary care provider were less likely to receive higher-dose prescriptions compared with faculty providers (odds ratio = 0.66, 95% confidence interval [CI]: 0.46–0.94), whereas patients with a nonlocal home address were more likely to be prescribed higher doses (odds ratio = 2.1, 95% CI: 1.5–2.9). Hispanic, Asian, and older patients were also less likely to be prescribed higher doses. Urine drug testing was not regularly completed (35% over 2 years), but odds of testing were higher for patients who self-identified as black, had resident primary care providers, lived locally, or were prescribed higher opioid doses.

Conclusions

In this academic clinical setting, patients with a resident primary care provider are less likely to receive higher-risk opioid prescriptions, as are Hispanic, Asian, and older patients. Black patients complete urine drug tests more frequently independent of other patient and provider characteristics. Additional studies are needed to assess why patients who travel larger distances to their primary care clinic are prescribed higher doses of opioids for chronic noncancer pain.
Negative mood disrupts self- and reward-biases in perceptual matching
Authors: Sui Jie , Ohrling Erik , Humphreys Glyn W.
Published: February 2016

There are established effects of self- and reward-biases even on simple perceptual matching tasks [Sui, J., He, X., & Humphreys, G. W. (2012). Perceptual effects of social salience: Evidence from self-prioritization effects on perceptual matching. Journal of Experimental Psychology, Human Perception and Performance, 38, 1105–1117]; however we know little about whether these biases can be modulated by particular interventions, and whether the biases then change in the same way. Here we assessed how the biases alter under conditions designed to induce negative mood. We had participants read a list of self-related negative or neutral mood statements [Velten, E. (1968). A laboratory task for induction of mood states. Behavior Research and Therapy, 6, 473–482] and also listen for 10 min to a passage of negative or neutral music, prior to carrying out perceptual matching with shapes associated to personal labels (self or stranger) or reward (£12 or £1). Responses to the self- and high-reward-associated shapes were selectively slower and less sensitive ( d′) following the negative mood induction procedures, and the decrease in mood correlated with decreases in the reaction time bias across “high saliency” (self and high-reward) stimuli. We suggest that negative mood may decrease self- and reward-biases through reducing attention to salient external stimuli.
Interpreting inertial fusion neutron spectra
Authors: Munro David H.
Published: February 2016

A burning laser fusion plasma produces a neutron spectrum first described by Brysk (1973 Plasma Phys. Control. Fusion
15 611). This and more recent work deals with the spectrum produced by a single fluid element. The distribution of temperatures and velocities in multiple fluid elements combine in any real spectrum; we derive formulas for how the neutron spectrum averages these contributions. The single element momentum spectrum is accurately Gaussian, but the multi-element spectrum exhibits higher moments. In particular, the skew and kurtosis are likely to be large enough to measure. Even the single fluid element spectrum may exhibit measurable directional anisotropy, so that instruments with different lines of sight should see different yields, mean velocities, mean temperatures, and higher moments. Finally, we briefly discuss how scattering in the imploded core modifies the neutron spectrum by changing the relative weighting of fuel regions with different temperatures and velocities.
Intrinsic plasma rotation and Reynolds stress at the plasma edge in the HSX stellarator
Authors: Wilcox R.S. , Talmadge J.N. , Anderson D.T. , Anderson F.S.B. , Lore J.D.
Published: February 2016

Using multi-tipped Langmuir probes in the edge of the HSX stellarator, the radial electric field and parallel flows are found to deviate from the values calculated by the neoclassical transport code PENTA for the optimized quasi-helically symmetric (QHS) configuration. To understand whether Reynolds stress might explain the discrepancy, fluctuating floating potential measurements are made at two locations in the torus corresponding to the low field and high field sides of the device. The measurements at the two locations show clear evidence of a gradient in the Reynolds stress. However, the resulting flow due to the gradient in the stress is found to be large and in opposite directions for the two locations. This makes an estimation of the flux surface average using a small number of measurement locations impractical from an experimental perspective. These results neither confirm nor rule out whether Reynolds stress plays an important role for the QHS configuration. Measurements made in configurations with the quasi-symmetry degraded show even larger flows and greater deviations from the neoclassically calculated velocity profiles than the QHS configuration while the fluctuation magnitudes are reduced. Therefore, for these configurations in particular, the Reynolds stress is most likely not responsible for the additional momentum.
Perturbative thermal diffusivity from partial sawtooth crashes in Alcator C-Mod
Authors: Creely A.J. , White A.E. , Edlund E.M. , Howard N.T. , Hubbard A.E.
Published: February 2016

Perturbative thermal diffusivity has been measured on Alcator C-Mod via the use of the extended-time-to-peak method on heat pulses generated by partial sawtooth crashes. Perturbative thermal diffusivity governs the propagation of heat pulses through a plasma. It differs from power balance thermal diffusivity, which governs steady state thermal transport. Heat pulses generated by sawtooth crashes have been used extensively in the past to study heat pulse thermal diffusivity (Lopes Cardozo 1995 Plasma Phys. Control. Fusion
37 799), but the details of the sawtooth event typically lead to non-diffusive ‘ballistic’ transport, making them an unreliable measure of perturbative diffusivity on many tokamaks (Fredrickson et al 2000 Phys. Plasmas
7 5051). Partial sawteeth are common on numerous tokamaks, and generate a heat pulse without the ‘ballistic’ transport that often accompanies full sawteeth (Fredrickson et al 2000 Phys. Plasmas
7 5051). This is the first application of the extended-time-to-peak method of diffusivity calculation (Tubbing et al 1987 Nucl. Fusion
27 1843) to partial sawtooth crashes. This analysis was applied to over 50 C-Mod shots containing both L- and I-Mode. Results indicate correlations between perturbative diffusivity and confinement regime (L- versus I-mode), as well as correlations with local temperature, density, the associated gradients, and gradient scale lengths (a/L

Te
and a/L

n
). In addition, diffusivities calculated from partial sawteeth are compared to perturbative diffusivities calculated with the nonlinear gyrokinetic code GYRO. We find that standard ion-scale simulations (ITG/TEM turbulence) under-predict the perturbative thermal diffusivity, but new multi-scale (ITG/TEM coupled with ETG) simulations can match the experimental perturbative diffusivity within error bars for an Alcator C-Mod L-mode plasma. Perturbative diffusivities extracted from heat pulses due to partial sawteeth provide a new constraint that can be used to validate gyrokinetic simulations.
Measurement and modelling of suprathermal electron bursts generated in front of a lower hybrid antenna
Authors: Gunn J.P. , Fuchs V. , Petržílka V. , Ekedahl A. , Fedorczak N. , Goniche M. , Hillairet J.
Published: February 2016

Measurements in the tokamak scrape-off layer show the existence of fast electrons as far as a few centimeters radially in front of a lower hybrid antenna grill, which is one order of magnitude further than earlier predictions of interaction zones not exceeding 5 mm in width (Rantamäki et al 2000 Nucl. Fusion
40 1477). The present contribution aims at understanding these experimental results on the basis of electron Landau damping in a turbulent scrape-off layer. A crucial guiding element from the experiments is the observation of temporal intermittency of the fast electron signal at positions radially away from the grill mouth at a rate comparable with the detachment rate of relatively hot and dense field-aligned plasma filaments, or ‘blobs,’ from the last closed flux surface. When the dynamic character of the scrape-off layer is taken into account, transient low density and low temperature states occur during which the Landau damping can be weak enough to allow the radiated spectrum to penetrate radially deep inward. When the lower hybrid wave intercepts a dense and hot ‘blob’ a few cm in front of the antenna, then strong damping of the high wave number components can occur. This is the scenario we propose for explaining the generation of fast electrons far away from the grill mouth.
Structural response of transient heat loading on a molybdenum surface exposed to low-energy helium ion irradiation
Authors: Sinclair G. , Tripathi J.K. , Diwakar P.K. , Hassanein A.
Published: February 2016

The advancement of fusion reactor engineering is currently inhibited by the lack of knowledge surrounding the stability of plasma facing components (PFCs) in a tokamak environment. During normal operation, events of high heat loading occur periodically where large amounts of energy are imparted onto the PFC surface. Concurrently, irradiation by low-energy helium ions present in the fusion plasma can result in the synthesis of a fibre form nanostructure on the PFC surface, called ‘fuzz’. In order to understand how this heterogeneous structure evolves and deforms in response to transient heat loading, a pulsed Nd:YAG millisecond laser is used to simulate these events on a fuzz form molybdenum (Mo) surface. Performance was analysed by three metrics: nanostructure evolution, particle emission, and improvement in optical properties. Experiments performed at the upper end of the expected range for type-I edge-localized modes (ELMs) found that the helium-induced nanostructure completely disappears after 200 pulses of the laser at 1.5 MJ m−2. In situ mass loss measurements found that the amount of particles leaving the surface increases as energy density increases and the rate of emission increases with pulse count. Finally, optical properties assisted in providing a qualitative indication of fuzz density on the Mo surface; after 400 pulses at 1.5 MJ m−2, the optical reflectivity of the damaged surface is ~90% of that of a mirror polished Mo sample. These findings provide different results than previous studies done with tungsten (W), and further help illustrate the complicated nature of how transient events of high heat loading in a tokamak environment might impact the performance and lifetime of PFCs in ITER and future DEMO devices (Ueda et al 2014 Fusion Eng. Des. 89 901–6).
3D simulations of gas puff effects on edge density and ICRF coupling in ASDEX Upgrade
Authors: Zhang W. , Bobkov V. , Lunt T. , Noterdaeme J.-M. , Coster D. , Bilato R. , Jacquet P. , Brida D. , Feng Y. , Wolfrum E. , Guimarais L.
Published: February 2016

In recent experiments, a local gas puff was found to be an effective way to tailor the scrape-off layer (SOL) density and improve the ion cyclotron range of frequency (ICRF) power coupling in tokamaks. In order to quantitatively reproduce these experiments, to understand the corresponding physics and to optimize the gas valve positions and rates, simulations were carried out with the 3D edge plasma transport code EMC3-EIRENE in ASDEX Upgrade. An inter-ELM phase of an H-mode discharge with a moderate gas puff rate (1.2  ×  1022 electrons s−1) is used in our simulations. We simulated cases with gas puff in the lower divertor, the outer mid-plane and the top of the machine while keeping other conditions the same. Compared with the lower divertor gas puff, the outer mid-plane gas puff can increase the local density in front of the antennas most effectively, while a toroidally uniform but significantly smaller enhancement is found for the top gas puff. Good agreement between our simulations and experiments is obtained. With further simulations, the mechanisms of SOL density tailoring via local gas puffing and the strategies of gas puff optimization are discussed in the paper.
Method to select gamma rays with energy above 50 GeV against a
charge-particle background in the GAMMA-400 space telescope
Authors: Kheymits M D , Leonov A A , Galper A M , Kadilin V , Arkhangelskaya I V , Arkhangelskiy A I , Gusakov Yu V , Zverev V G , Kaplin V , Naumov P Yu , Runtso M F , Suchkov S I , Topchiev N P , Yurkin Yu T , Bakaldin A , Dalkarov O
Published: February 2016

Studying high-energy (>50GeV) cosmic gamma radiation raises a problem of selection
of neutral gamma rays from a background of charged particles. The problem is
embarrassed by the backsplash effect. The backsplash consists, in the main, of
low-energy (1 MeV) secondary photons moving backwards and is produced by any
high-energy gamma quantum. A charged-particle rejection method using the
anticoincidence and time-of-flight systems is proposed. Charged-particle events are
distinguished from those being triggered by high-energy gamma-rays producing
backsplash. The method is based on the time separation of signals. It allows us to
keep the gamma-ray detection efficiency high up to high energies.
Method of incident low-energy gamma-ray direction reconstruction in the GAMMA-400 gamma-ray space telescope
Authors: Kheymits M D , Leonov A A , Zverev V G , Galper A M , Arkhangelskaya I V , Arkhangelskiy A I , Suchkov S I , Topchiev N P , Yurkin Yu T , Bakaldin A V , Dalkarov O D
Published: February 2016

The GAMMA-400 gamma-ray space-based telescope has as its main goals to measure cosmic γ-ray fluxes and the electron-positron cosmic-ray component produced, theoretically, in dark-matter-particles decay or annihilation processes, to search for discrete γ-ray sources and study them in detail, to examine the energy spectra of diffuse γ-rays — both galactic and extragalactic — and to study gamma-ray bursts (GRBs) and γ-rays from the active Sun. Scientific goals of GAMMA-400 telescope require fine angular resolution. The telescope is of a pair-production type. In the converter-tracker, the incident gamma-ray photon converts into electron-positron pair in the tungsten layer and then the tracks are detected by silicon- strip position-sensitive detectors. Multiple scattering processes become a significant obstacle in the incident-gamma direction reconstruction for energies below several gigaelectronvolts. The method of utilising this process to improve the resolution is proposed in the presented work.
Elastodynamic models for extending GTD to penumbra and finite size flaws
Authors: Djakou A Kamta , Darmon M , Potel C
Published: February 2016

The scattering of elastic waves from an obstacle is of great interest in ultrasonic Non Destructive Evaluation (NDE). There exist two main scattering phenomena: specular reflection and diffraction. This paper is especially focused on possible improvements of the Geometrical Theory of Diffraction (GTD), one classical method used for modelling diffraction from scatterer edges. GTD notably presents two important drawbacks: it is theoretically valid for a canonical infinite edge and not for a finite one and presents discontinuities around the direction of specular reflection. In order to address the first drawback, a 3D hybrid method using both GTD and Huygens secondary sources has been developed to deal with finite flaws. ITD (Incremental Theory of Diffraction), a method developed in electromagnetism, has also been developed in elastodynamics to deal with small flaws. Experimental validation of these methods has been performed. As to the second drawback, a GTD uniform correction, the UTD (Uniform Theory of Diffraction) has been developed in the view of designing a generic model able to correctly simulate both specular reflection and diffraction. A comparison has been done between UTD numerical results and UAT (Uniform Asymptotic Theory of Diffraction) which is another uniform solution of GTD.
The dynamic excitation of a granular chain for biomedical ultrasound applications: contact mechanics finite element analysis and validation
Authors: Gélat P , Yang J. , Thomas P J , Hutchins D A , Akanji O , Davis L A J , Freear S , Harput S , Saffari N
Published: February 2016

There has been recent interest in the transmission of acoustic signals along granular chains of spherical beads to produce waveforms of relevance to biomedical ultrasound applications. Hertzian contact between adjacent beads can introduce different harmonic content into the signal as it propagates. This transduction mechanism has the potential to be of use in both diagnostic and therapeutic ultrasound applications, and is the object of the study presented here. Although discrete dynamics models of this behaviour exist, a more comprehensive solution must be sought if changes in shape and deformation of individual beads are to be considered. Thus, the finite element method was used to investigate the dynamics of a granular chain of six, 1 mm diameter chrome steel spherical beads excited at one end using a sinusoidal displacement signal at 73 kHz. Output from this model was compared with the solution provided by the discrete dynamics model, and good overall agreement obtained. In addition, it was able to resolve the complex dynamics of the granular chain, including the multiple collisions which occur. It was demonstrated that under dynamic excitation conditions, the inability of discrete mechanics models to account for elastic deformation of the beads when these lose contact, could lead to discrepancies with experimental observations.
Use of herbarium data to evaluate weediness in five congeners
Authors: Hanan-A. Ana M. , Vibrans Heike , Cacho N. Ivalú , Villaseñor José L. , Ortiz Enrique , Gómez-G. Vinicio A.
Published: February 2016

It is often desirable to quantify a plant's relative weediness or synanthropy, that is, the degree to which a species associates with human-caused disturbance, in order to study and understand the biology, ecology and evolution of weeds and invasive plants. Herbarium specimens are among the most accessible and verifiable sources of data on distribution and habitat. However, the habitat distribution of species may not be reflected accurately by herbarium specimen data, due to well-known biases in plant collection. Here, we assess how well herbarium specimens reflect species' weediness, when compared with direct field surveys. We used five species of Melampodium (Asteraceae) and classified their degree of weediness with a modification of Nuorteva's synanthropy index, based on herbarium specimens. We then modelled the distribution of our focal species in Mexico using MaxEnt and identified a polygon of ∼3000 km 2 in the state of Nayarit, Mexico, where there was a high probability of finding all five species. Systematic field searches in the target area documented all visible populations of four species along major and minor roads. Then we, again, classified their degree of weediness with the synanthropy index, based now on field data, and compared. We found that herbarium data were an accurate predictor of a species' weediness relative to its congeners despite the well-documented skew of herbarium data towards natural areas, which our data reflected as well. So, herbarium data can be used to classify species' weediness relative to each other, but not in absolute terms, if the specimens were correctly identified and none of the species were subject to particular collection bias. This study is the first attempt to compare herbarium and field data on this subject and may be relevant for other types of investigations based on herbarium data. Our work also highlights the usefulness of distribution models based on herbarium specimens.
Capsule endoscopy is useful diagnostic tool for diagnosing Meckel’s diverticulum
Authors: Krstic Slobodan N. , Martinov Jelena B. , Sokic-Milutinovic Aleksandra D. , Milosavljevic Tomica N. , Krstic Miodrag N.
Published: February 2016

Objective

Meckel’s diverticulum (MD) is the most common congenital anomaly of the gastrointestinal tract. Although a majority of patients remain asymptomatic, complications may occur in a subset of patients. MD is a rare cause of gastrointestinal bleeding (GIB) in adults. We aimed to clarify the possible role of capsule endoscopy (CE) in the identification of Meckel’s diverticulum.

Patients and methods

From October 2004 to December 2010, 157 CEs were performed (83 male individuals, mean age 51±20 years; range 3–83 years) for obscure GIB. Before CE, all patients underwent nonconclusive upper and lower endoscopy at least two times and barium follow-through.

Results

CE identified the source of bleeding in 70/157 patients (44.6%). MD was diagnosed in 13/70 (18.6%) patients (11 male individuals, mean age 35±20 years, range, 3–69 years) after CE. Nine patients presented with obscure overt and four with obscure occult bleeding. The mean duration of obscure GIB history was 13 months (range 1–72 months). The mean hemoglobin concentration at the time of the procedure was 115±12 g/l. The findings of MD on CE were double lumen sign (13/13), visible blood (7/13), and diaphragm sign (6/13). All patients were operated upon, and MD histologically verified in 11. In two patients CE was false-positive and in two patients, false-negative. Capsule endoscopy had a positive predictive value of 84.6% for the diagnosis of MD.

Conclusion

MD should be considered in the differential diagnosis of obscure GIB in adults. CE is an effective and promising modality for diagnosing MD in patients with obscure GIB.
RNA structure through multidimensional chemical mapping
Authors: Tian Siqi , Das Rhiju
Published: February 2016

The discoveries of myriad non-coding RNA molecules, each transiting through multiple flexible states in cells or virions, present major challenges for structure determination. Advances in high-throughput chemical mapping give new routes for characterizing entire transcriptomesin vivo,but the resulting one-dimensional data generally remain too information-poor to allow accuratede novostructure determination. Multidimensional chemical mapping (MCM) methods seek to address this challenge. Mutate-and-map (M2), RNA interaction groups by mutational profiling (RING-MaP and MaP-2D analysis) and multiplexed ·OH cleavage analysis (MOHCA) measure how the chemical reactivities of every nucleotide in an RNA molecule change in response to modifications at every other nucleotide. A growing body ofin vitroblind tests and compensatory mutation/rescue experiments indicate that MCM methods give consistently accurate secondary structures and global tertiary structures for ribozymes, ribosomal domains and ligand-bound riboswitch aptamers up to two hundred nucleotides in length. Importantly, MCM analyses provide detailed information on structurally heterogeneous RNA states, such as ligand-free riboswitches, that are functionally important but difficult to resolve with other approaches. The sequencing requirements of currently available MCM protocols scale at least quadratically with RNA length, precluding general application to transcriptomes or viral genomes at present. We propose a modify-crosslink-map expansion to overcome this and other current limitations to resolving thein vivo‘RNA structurome’.
Crystal structure of ethyl 3-amino-6-methyl-2-[(4-methylphenyl)carbamoyl]-4-[(E)-2-phenylethenyl]thieno[2,3-b]pyridine-5-carboxylate monohydrate
Authors: Mague Joel T. , Akkurt Mehmet , Mohamed Shaaban K. , Bakhite Etify A. , Albayati Mustafa R.
Published: February 2016

In the title molecule, C27H25N3O3S·H2O, the dihedral angle between the planes of the thienyl ring and the pendantp-tolyl group is 39.25 (6)°, while that between the pyridine ring and the pendant phenyl ring is 44.37 (6)°. In addition, there is a slight twist in the bicyclic core, with a dihedral angle of 2.39 (4)° between the thienyl and pyridine rings. The conformation of the carbamoyl moiety is partially determined by an intramolecular N—H...O hydrogen bond. In the crystal, complementary N—H...O hydrogen bonds form dimers which are then associated into chains parallel to thecaxis through O—H...N hydrogen bonds involving the water molecule of crystallization. Electron density associated with an additional solvent molecule of partial occupancy and disordered about a twofold axis was removed with the SQUEEZE procedure inPLATON[Spek (2015).Acta Cryst.C71, 9–18]. The given chemical formula and other crystal data do not take into account the unknown solvent molecule(s).
Crystal structure ofS-hexyl (E)-3-(2-hydroxybenzylidene)dithiocarbazate
Authors: Begum M. S. , Howlader M. B. H. , Sheikh M. C. , Miyatake R. , Zangrando E.
Published: February 2016

The title compound, C14H20N2OS2[systematic name:S-hexyl (E)-2-(2-hydroxybenzylidene)hydrazine-1-carbodithioate], crystallizes with four independent molecules (A–D) in the asymmetric unit. All four molecules adopt anEconformation with respect to the C=N bond of the benzylidene moiety and have an intramolecular O—H...N hydrogen bond generating anS(6) ring motif. In the crystal, theAandDmolecules are connected by a pair N—H...S hydrogen bonds, forming a dimer with anR22(8) ring motif. In the case of moleculesBandC, they are linked to themselves by pairs of N—H...S hydrogen bonds, formingB–BandC–Cinversion dimers withR22(8) ring motifs.
Symmetry reduction due to gallium substitution in the garnet Li6.43(2)Ga0.52(3)La2.67(4)Zr2O12
Authors: Robben Lars , Merzlyakova Elena , Heitjans Paul , Gesing Thorsten M.
Published: February 2016

Single-crystal structure refinements on lithium lanthanum zirconate (LLZO; Li7La3Zr2O12) substituted with gallium were successfully carried out in the cubic symmetry space groupI\overline{4}3d. Gallium was found on two lithium sites as well as on the lanthanum position. Due to the structural distortion of the resulting Li6.43(2)Ga0.52(3)La2.67(4)Zr2O12(Ga–LLZO) single crystals, a reduction of the LLZO cubic garnet symmetry fromIa\overline{3}dtoI\overline{4}3dwas necessary, which could hardly be analysed from X-ray powder diffraction data.
Redetermination of brackebuschite, Pb2Mn3+(VO4)2(OH)
Authors: Lafuente Barbara , Downs Robert T.
Published: February 2016

The crystal structure of brackebuschite, ideally Pb2Mn3+(VO4)2(OH) [dilead(II) manganese(III) vanadate(V) hydroxide], was redetermined based on single-crystal X-ray diffraction data of a natural sample from the type locality Sierra de Cordoba, Argentina. Improving on previous results, anisotropic displacement parameters for all non-H atoms were refined and the H atom located, obtaining a significant improvement of accuracy and an unambiguous hydrogen-bonding scheme. Brackebuschite belongs to the brackebuschite group of minerals with general formulaA2M(T1O4)(T2O4)(OH, H2O), withA= Pb2+, Ba, Ca, Sr;M= Cu2+, Zn, Fe2+, Fe3+, Mn3+, Al;T1 = As5+, P, V5+; andT2 = As5+, P, V5+, S6+. The crystal structure of brackebuschite is based on a cubic closest-packed array of O and Pb atoms with infinite chains of edge-sharing [Mn3+O6] octahedra located about inversion centres and decorated by two unique VO4tetrahedra (each located on a special position 2e, site symmetrym). One type of VO4tetrahedra is linked with the1∞[MnO4/2O2/1] chain by one common vertex, alternating with H atoms along the chain, while the other type of VO4tetrahedra link two adjacent octahedra by sharing two vertices with them and thereby participating in the formation of a three-membered Mn2V ring between the central atoms. The1∞[Mn3+(VO4)2OH] chains run parallel to [010] and are held together by two types of irregular [PbOx] polyhedra (x= 8, 11), both located on special position 2e(site symmetrym). The magnitude of the libration component of the O atoms of the1∞[Mn3+(VO4)2OH] chain increases linearly with the distance from the centerline of the chain, indicating a significant twisting to and fro of the chain along [010]. The hydroxy group bridges one Pb2+cation with two Mn3+cations and forms an almost linear hydrogen bond with a vanadate group of a neighbouring chain. The O...O distance of this interaction determined from the structure refinement agrees well with Raman spectroscopic data.
Structure cristalline du composé Hg3-xSbx(S+Se)2+xI2-x(x≃ 0.1)
Authors: Kars Mohammed , Herrero Adrian Gómez , Roisnel Thierry , Rebbah Allaoua , Otero-Diáz L. Carlos
Published: February 2016

Single crystals of the mercury chalcohalide Hg3-xSbx(S+Se)2+xI2-x(x≃ 0.1) (mercury antimony sulfide selenide iodide), were grown by a chemical transport reaction. The structure contains three independentA(Hg/Sb) atoms; each atom is strongly covalently bonded with twoX(Se/S) atoms to form approximately linearX–A–Xunits. TheX–A–Xunits link to formA4X4rings, which are combined into infinite crankshaft-type bands running along the [100] direction. Four equatorialE(I/X= Se,S) atoms at relatively long distances complete the distorted octahedral coordination ofA(Hg/Sb). The crystal under investigation was twinned by non-merohedry with a refined twin domain fraction of 0.814 (6):0.186 (6). The structure is isotypic with Hg3Se2I2[Beck & Hedderich (2000).J. Solid State Chem.151, 73–76], but the current determination reveals a coupled substitution, with partial replacement of Hg+2by Sb+3, balanced by the equivalent substitution of I−1by S−2and Se−2. Bond-valence calculations are consistent with this relative substitution model.
N,N,N′,N′-Tetramethyl-N′′-[2-(trimethylazaniumyl)ethyl]guanidinium bis(tetraphenylborate) acetone disolvate
Authors: Tiritiris Ioannis , Kantlehner Willi
Published: February 2016

The asymmetric unit of the title solvated salt, C10H26N42+·2C24H20B−·2C3H6O, comprises one cation, two tetraphenylborate ions and two acetone solvent molecules. The N and methyl C atoms of the terminal trimethylammonium group are disordered over two sets of sites, with a refined occupancy ratio of 0.846 (3):0.154 (3). The C—N bond lengths in the central C3N unit of the guanidinium ion range between 1.3308 (16) and 1.3508 (16) Å, indicating a degree of double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charge is delocalized in the CN3plane. The C—N bond lengths in the terminal trimethylammonium group have values close to that of a typical single bond, and the second positive charge is localized there. In the crystal, the guanidinium ion is connected by N—H...O and C—H...O hydrogen bonds with the acetone molecules. C—H...π interactions are present between the guanidinium H atoms and the phenyl rings of the tetraphenylborate ions, leading to the formation of a two-dimensional supramolecular pattern along thebcplane.
Limonin isolated from the seeds ofCitrus limetta(Indian sweet lemon)
Authors: Bauri A. K. , Foro Sabine , Nhu Quynh Nguyen Do
Published: February 2016

The title molecule, C26H30O8[systematic name: (4aS,14bR)-12-(furan-3-yl)-6,6,8a,12a-tetramethyldecahydro-1H,3H-oxireno[2,3-d]pyrano[4′,3′:3,3a]isobenzofuro[5,4-f]isochromene-3,8,10(6H,9aH)-trione], commonly known as limonin, is an antiproliferative polyoxgenated bioactive molecule. It comprises a fused cyclic system containing a cyclohexane (D), a cyclohexanone (C), a furan (B), an epoxide and two lactone rings (AandE). In addition to these rings, a second furan ring (F) is present as a substituent. Only the cyclohexane (D) ring has a chair conformation; the other six-membered rings (A,CandE) have twist-boat conformations due to steric hinderance or bonding strain. In the crystal, molecules are linked by C—H...O hydrogen bonds, forming a three-dimensional structure.
2,4-Di-tert-butyl-6-({[(R)-1-phenylethyl]amino}methyl)phenol
Authors: Zhang Fangqin , Zhang Yongbin , Liu Diansheng
Published: February 2016

There are two molecules in the asymmetric unit of the title compound, C23H33NO, in which the dihedral angles between the aromatic rings are 72.1 (3) and 89.0 (2)°. One of the molecules features atert-butyl group disordered over two sets of sites in a 0.545 (13):0.455 (13) ratio. Both molecules feature an intramolecular O—H...N hydrogen bond, which closes anS(6) ring. Neither of the N—H groups participates in hydrogen bonds, perhaps due to steric crowding.
Bis(1,10-phenanthroline-κ2N,N′)platinum(II) bis(3-carboxybenzenesulfonate) dihydrate
Authors: Liu Jing , Zhu Long-Guan
Published: February 2016

The title complex, [Pt(C12H8N2)2](C7H5O5S)2·2H2O, consists of a complex cation [Pt(1,10-phen)2]2+(1,10-phen = 1,10-phenanthroline), two 3-sulfobenzoate anions and two lattice water molecules. In the crystal, anions and water molecules form hydrogen-bonded centrosymmetric dimers. In addition, π–π interactions are observed between 1,10-phenanthroline ligands and 3-sulfobenzoate anions.
The main topics of research on disclosures of intangible assets: a critical review
Authors: Castilla-Polo Francisca , GALLARDO-VÁZQUEZ Dolores
Published: February 2016

Purpose

– We must acknowledge the importance of intangibles in today’s economies and the controversy over the accounting and reporting of these assets. For this reason, the purpose of this paper is to synthesize the lessons learned from research to date and identify gaps in that research that would be useful to academics and practitioners.

Design/methodology/approach

– The literature review was conducted after an analysis of the most important academic databases in the period of 1990-2013: ABI Inform Complete, CSIS, EconLit, ISOC, Journal Citation Reports, Scopus, Emerald, Springer, and Google Scholar.

Findings

– The authors offer a summary of the main gaps in the literature on intellectual capital disclosures, among which the authors perceive a need for increased qualitative or explanatory research, which would allow further analysis of such decisions.

Research limitations/implications

– Specifically, the main problem encountered in the research on voluntary disclosure of intangibles appears to relate to the type of methodology used, which is usually quantitative or descriptive.

Practical implications

– Given that the principal limitations in the field of the disclosure of intangibles have been discussed, the authors conclude by indicating the principal directions for future research.

Social implications

– Qualitative analysis is absent in the literature the authors reviewed, and considered it fundamental to understanding this type of disclosure. In fact, the development of future lines of research could provide better-quality intangible asset reporting.

Originality/value

– Although there are previous studies on this topic, the authors believe that the main contribution of this study is to offer an integrated framework of existing findings concerning decisions by companies to disclose information on intangibles, a topic on which previous literature is sparse.
Open air markets: uniquenesses about African marketing channels
Authors: Onyemah Vincent , Akpa Simon O.
Published: February 2016

Purpose

– The purpose of this paper is to offer a state of the art description of open air markets (OAM), a little-known phenomenon that is indispensable in Africa’s consumer packaged goods industry.

Design/methodology/approach

– A qualitative methodology comprising in-depth semi-structured interviews and direct observation was employed.

Findings

– Analysis of data from Nigeria, Africa’s largest economy and most populous country, reveals that channel members have roles that are different from that of their Western counterparts. For example, distributors often do not distribute and principals are expected to actively sell on behalf of their distributors to empty the latter’s warehouse. Also, while many end-users in developing countries expect credit sales and opportunity to bargain, extant literature does not include these demands in the formal list of service output demands. Another major finding is the surprising order underlying OAM. It is the bedrock of commercial activities: for most consumer packaged goods manufacturers, sales through OAM account for over 90 percent of revenue.

Research limitations/implications

– The focus on one industry and country limits the generalizability of the above findings.

Practical implications

– Africa is the next growth frontier. Tapping into this growth requires a deep understanding and appreciation of the important role played by its unique marketing channels.

Originality/value

– Given the dearth of documented knowledge about marketing channels in emerging markets, this study addresses an important gap. Its findings could inform theory development and encourage more research on marketing channels in developing countries.
(Un)Conditional surrender? Why do professionals willingly comply with managerialism
Authors: Alvesson Mats , Spicer André
Published: February 2016

Purpose

– The purpose of this paper is to explore the question – why do professionals surrender their autonomy? This paper looks at the case of academics, in particular business school academics. It traces how this group of professionals have progressively surrendered their autonomy and complied with the demands of managerialism.

Design/methodology/approach

– This largely theoretical paper looks to develop an understanding of (over)compliance with the bureaucratization of research using the four faces of power – coercive, agenda setting, ideological and discursive.

Findings

– The discussion of this paper argues that the surrendering of autonomy has been reinforced through coercive forms of power like rewards and punishment and bureaucratization; manipulation and mainstreaming through pushing a particular version of research to the top of the agenda; domination through shaping norms and values; and subjectification through creating new identities.

Originality/value

– The paper explores how academics deal with tensions and paradoxes such as compliance and resistance, as well as love of work and loathing of it. To deal with these paradoxes, academics often treat their work as a game and see themselves as players. While this process enables academics to reconcile themselves with their loss of autonomy, it has troubling collective outcomes: the production of increasing uninteresting and irrelevant research.
Slawek Magala’s view on management of meaning and organisational change
Authors: Fink Gerhard , Dauber Daniel
Published: February 2016

Purpose

– The purpose of this paper is to show that Slawek Magala’s theory of management of meaning in organisations can be considered as a step towards a generic theory of organisational change.

Design/methodology/approach

– The authors are integrating Slawek Magala’s views on the processes, which play a role in changing organisations (i.e. framing, reflecting, negotiating, and seeking new windows of opportunities) with the related types of narratives as developed by David Boje (2001, 2008) and with further extensions by Fink and Yolles (2012), which are based on a model of paradigm change.

Findings

– The authors develop a theoretical framework, which might serve as a basis for analysis of change processes emerging from different contexts within or outside a firm and offer some reflections about comparing research into issues of organisational change.

Research limitations/implications

– This is a theoretical viewpoint paper.

Practical implications

– The extension of Magala’s model offers a practical guide for research into organisational change processes.

Social implications

– Magala’s model offers a deeper understanding of actual change processes.

Originality/value

– To the authors’ knowledge, this is the first time where a concept about emergent causality deriving from interaction between two conflicting agents (i.e. involved parties as, e.g. managers and subordinates) is applied to emerging stages in change processes.