bluuebunny/crossref_metadata_2025 huggingface dataset:
Constant-current control method of multi-function electromagnetic transmitter
Authors: Xue Kaichang , Zhou Fengdao , Wang Shuang , Lin Jun
Published: February 2015

Based on the requirements of controlled source audio-frequency magnetotelluric, DC resistivity, and induced polarization, a constant-current control method is proposed. Using the required current waveforms in prospecting as a standard, the causes of current waveform distortion and current waveform distortion’s effects on prospecting are analyzed. A cascaded topology is adopted to achieve 40 kW constant-current transmitter. The responsive speed and precision are analyzed. According to the power circuit of the transmitting system, the circuit structure of the pulse width modulation (PWM) constant-current controller is designed. After establishing the power circuit model of the transmitting system and the PWM constant-current controller model, analyzing the influence of ripple current, and designing an open-loop transfer function according to the amplitude-frequency characteristic curves, the parameters of the PWM constant-current controller are determined. The open-loop transfer function indicates that the loop gain is no less than 28 dB below 160 Hz, which assures the responsive speed of the transmitting system; the phase margin is 45°, which assures the stabilization of the transmitting system. Experimental results verify that the proposed constant-current control method can keep the control error below 4% and can effectively suppress load change caused by the capacitance of earth load.
A magnetic tunnel to shelter hyperpolarized fluids
Authors: Milani Jonas , Vuichoud Basile , Bornet Aurélien , Miéville Pascal , Mottier Roger , Jannin Sami , Bodenhausen Geoffrey
Published: February 2015

To shield solutions carrying hyperpolarized nuclear magnetization from rapid relaxation during transfer through low fields, the transfer duct can be threaded through an array of permanent magnets. The advantages are illustrated for solutions containing hyperpolarized 1H and 13C nuclei in a variety of molecules.
Feasibility of a 90° electric sector energy analyzer for low energy ion beam characterization
Authors: Mahinay C. L. S. , Wada M. , Ramos H. J.
Published: February 2015

A simple formula to calculate refocusing by locating the output slit at a specific distance away from the exit of 90° ion deflecting electric sector is given. Numerical analysis is also performed to calculate the ion beam trajectories for different values of the initial angular deviation of the beam. To validate the theory, a compact (90 mm × 5.5 mm × 32 mm) 90° sector ESA is fabricated which can fit through the inner diameter of a conflat 70 vacuum flange. Experimental results show that the dependence of resolution upon the distance between the sector exit and the Faraday cup agrees with the theory. The fabricated 90° sector electrostatic energy analyzer was then used to measure the space resolved ion energy distribution functions of an ion beam with the energy as low as 600 eV.
Gaussian Markov transition models of molecular kinetics
Authors: Wu Hao , Noé Frank
Published: February 2015

The slow processes of molecular dynamics (MD) simulations—governed by dominant eigenvalues and eigenfunctions of MD propagators—contain essential information on structures of and transition rates between long-lived conformations. Existing approaches to this problem, including Markov state models and the variational approach, represent the dominant eigenfunctions as linear combinations of a set of basis functions. However the choice of the basis functions and their systematic statistical estimation are unsolved problems. Here, we propose a new class of kinetic models called Markov transition models (MTMs) that approximate the transition density of the MD propagator by a mixture of probability densities. Specifically, we use Gaussian MTMs where a Gaussian mixture model is used to approximate the symmetrized transition density. This approach allows for a direct computation of spectral components. In contrast with the other Galerkin-type approximations, our approach can automatically adjust the involved Gaussian basis functions and handle the statistical uncertainties in a Bayesian framework. We demonstrate by some simulation examples the effectiveness and accuracy of the proposed approach.
Metalorganic chemical vapor deposition growth of high-mobility AlGaN/AlN/GaN heterostructures on GaN templates and native GaN substrates
Authors: Chen Jr-Tai , Hsu Chih-Wei , Forsberg Urban , Janzén Erik
Published: February 2015

Severe surface decomposition of semi-insulating (SI) GaN templates occurred in high-temperature H2 atmosphere prior to epitaxial growth in a metalorganic chemical vapor deposition system. A two-step heating process with a surface stabilization technique was developed to preserve the GaN template surface. Utilizing the optimized heating process, a high two-dimensional electron gas mobility ∼2000 cm2/V·s was obtained in a thin AlGaN/AlN/GaN heterostructure with an only 100-nm-thick GaN spacer layer homoepitaxially grown on the GaN template. This technique was also demonstrated viable for native GaN substrates to stabilize the surface facilitating two-dimensional growth of GaN layers. Very high residual silicon and oxygen concentrations were found up to ∼1 × 1020 cm−3 at the interface between the GaN epilayer and the native GaN substrate. Capacitance-voltage measurements confirmed that the residual carbon doping controlled by growth conditions of the GaN epilayer can be used to successfully compensate the donor-like impurities. State-of-the-art structural properties of a high-mobility AlGaN/AlN/GaN heterostructure was then realized on a 1 × 1 cm2 SI native GaN substrate; the full width at half maximum of the X-ray rocking curves of the GaN (002) and (102) peaks are only 21 and 14 arc sec, respectively. The surface morphology of the heterostructure shows uniform parallel bilayer steps, and no morphological defects were noticeable over the entire epi-wafer.
A physical scaling model for aggregation and disaggregation of field-scale surface soil moisture dynamics
Authors: Ojha Richa , Govindaraju Rao S.
Published: February 2015

Scaling relationships are needed as measurements and desired predictions are often not available at concurrent spatial support volumes or temporal discretizations. Surface soil moisture values of interest to hydrologic studies are estimated using ground based measurement techniques or utilizing remote sensing platforms. Remote sensing based techniques estimate field-scale surface soil moisture values, but are unable to provide the local-scale soil moisture information that is obtained from local measurements. Further, obtaining field-scale surface moisture values using ground-based measurements is exhaustive and time consuming. To bridge this scale mismatch, we develop analytical expressions for surface soil moisture based on sharp-front approximation of the Richards equation and assumed log-normal distribution of the spatial surface saturated hydraulic conductivity field. Analytical expressions for field-scale evolution of surface soil moisture to rainfall events are utilized to obtain aggregated and disaggregated response of surface soil moisture evolution with knowledge of the saturated hydraulic conductivity. The utility of the analytical model is demonstrated through numerical experiments involving 3-D simulations of soil moisture and Monte-Carlo simulations for 1-D renderings—with soil moisture dynamics being represented by the Richards equation in each instance. Results show that the analytical expressions developed here show promise for a principled way of scaling surface soil moisture.
Studies on characteristics of resistive power calculated with discrete Fourier transform in a pulse-modulated radio frequency discharge
Authors: Huo W. G. , Zhang H. , Ding Z. F.
Published: February 2015

In a pulse-modulated (PM) radio-frequency (RF) capacitively coupled plasma, the DFT (Discrete Fourier Transform)-calculated RF power and the corresponding phase shift between voltage and current measured with calibrated voltage and current probes present oscillations in the pulse rising and falling edges. The oscillating phase shift between voltage and current obtained in the falling edge is outside the expected value for a resistive-capacitive RF discharge. Numerical simulation and analytical analysis are made to interpret these abnormal characteristics and seek an approach to obtaining the reliable resistive (active) RF power. The oscillation is proved to be originated from the oscillating non-zero reactive RF power of the capacitor(s) in the load. At the time instant when the reactive RF power within an integer RF period is not zero, the reactive RF power is mistakenly regarded as the active RF power in the DFT analysis, as a result, the corresponding phase is thus incorrect and even outside the expected value for a resistive-capacitive load. The resistive RF power and the phase can be only correctly calculated at the time instant when the reactive RF power is zero. For a series (or parallel) RC (resistor-capacitor) load and a combined RC load with the dominated series (or parallel) RC impedance, the time instant of the zero reactive RF power is calculated with one of the two proposed empirical formulae. In practice, the DFT-calculated resistive RF power is obtained according to the following procedures: (1) applying DFT to the measured RF voltage and current signals to obtain the power and time instants for minimal phase shifts between voltage and current; (2) selecting the empirical formula to calculate time instants of the zero reactive RF power; (3) getting resistive powers at time instants of the zero reactive RF power. In real PM RF capacitively coupled plasmas, the empirical formula for the series RC load is selected to calculate the resistive RF power. The accuracy of DFT-calculated resistive RF power is proved to be related to two kinds of errors. The first is the error of the time instant of the zero reactive RF power calculated using the empirical formula. This error is relatively lower when the requirement that the dominated parallel or series RC impedance is met and is almost independent of the impedance phase angle of a combined RC load. The second is the error of the DFT-calculated resistive RF power compared with the corresponding time integral RF power at the real zero reactive RF power. This error is independent of the load type or the load impedance but varies with the slope of PM RF voltage amplitude vs. time. The two kinds of errors both increase in the pulse rising and falling edges.
Spontaneous formation of superconducting NiBi3 phase in Ni-Bi bilayer films
Authors: Siva Vantari , Senapati Kartik , Satpati Biswarup , Prusty Sudakshina , Avasthi D. K. , Kanjilal D. , Sahoo Pratap K.
Published: February 2015

We report the spontaneous formation of superconducting NiBi3 phase in thermally evaporated Ni-Bi bilayer films. High reaction-diffusion coefficient of Bi is believed to drive the formation of NiBi3 during the deposition of Bi on the Ni film. Cross sectional transmission electron microscopy and glancing incidence X-ray depth profiling confirmed the presence of NiBi3 throughout the top Bi layer. Superconducting transition at ∼3.9 K, close to the bulk value, was confirmed by transport and magnetization measurements. The bilayers were irradiated with varying fluence of 100 MeV Au ions to study the robustness of superconducting order in presence of large concentration of defects. Superconducting parameters of NiBi3, such as transition temperature and upper critical field, remained unchanged upto an ion dose of 1 × 1014 ions/cm2. The diffusive formation of NiBi3 in Ni opens the possibility of studying superconducting proximity effect at a truly clean superconductor-ferromagnet interface.
Lattice dynamics and broad-band dielectric properties of multiferroic Pb(Fe1/2Nb1/2)O3 ceramics
Authors: Mackeviciute R. , Goian V. , Greicius S. , Grigalaitis R. , Nuzhnyy D. , Holc J. , Banys J. , Kamba S.
Published: February 2015

Complex dielectric properties of Pb(Fe1/2Nb1/2)O3 ceramics were investigated in a broad frequency range from 100 Hz up to 90 THz. A broad dielectric anomaly was observed near the temperature of the ferroelectric phase transition (TC1 = 376 K). Below 1 MHz, the anomaly is strongly influenced by conductivity of the sample, but higher frequency data taken up to 81 MHz reveal a broad and frequency independent peak at TC1 typical for a diffuse ferroelectric phase transition. Surprisingly, dielectric permittivity measured at 37 GHz exhibits a peak shifted by 25 K above TC1, which indicates polar nanoregions with dynamics in microwave frequency region. A dielectric relaxation, which appears in THz region below 700 K, slows down towards TC1 and again hardens below TC2 = 356 K. This central mode drives both phase transitions, so they belong to order–disorder type, although the polar phonons exhibit anomalies near both phase transitions. In the paraelectric phase, infrared reflectivity spectra correspond to local Fm3¯m structure due to short-range chemical ordering of Fe and Nb cations on the B perovskite sites. Moreover, each polar phonon is split due to two different cations on the B sites. Recently, Manley et al. [Nat. Commun. 5, 3683 (2014)] proposed a new mechanism of creation of polar nanoregions in relaxor ferroelectrics. They argued, based on their inelastic neutron scattering studies of PMN–PT, that the TO1 phonon is split and interaction of both components gives rise to so called Anderson phonon localization, which can produce regions of trapped standing waves and these waves induce polar nanoregions in relaxors. We cannot exclude or confirm this mechanism, but we show that the splitting of polar phonons is a common feature for all complex perovskites with relaxor ferroelectric behavior and it can be also observed in canonical ferroelectric BaTiO3, where the soft mode is split in paraelectric phase due to a strong lattice anharmonicity.
Epitaxial Fe3Pt/FePt nanocomposites on MgO and SrTiO3
Authors: Casoli F. , Lupo P. , Nasi L. , Cabassi R. , Fabbrici S. , Bolzoni F. , Ranzieri P. , Albertini F.
Published: February 2015

We have exploited the pseudomorphic growth of the magnetically soft Fe3Pt phase on top of L10-FePt to obtain fully epitaxial soft/hard nanocomposites on both MgO(100) and SrTiO3(100). The magnetic properties of this new nanocomposite system, driven by the soft/hard exchange-coupling, can be tailored by varying soft phase thickness, soft phase magnetic anisotropy and substrate. Coercivity is strongly reduced by the addition of the soft phase, a reduction which is definitely affected by the nominal composition of the soft phase and by the substrate choice; similarly is the magnetic phase diagram of the composite system. Coercive field decreases down to 21% of the hard layer value for Fe3Pt(5 nm)/FePt(3.55 nm) nanocomposites on SrTiO3; this maximum coercivity reduction was obtained with a nominal atomic content of Fe in the soft phase of 80%.
Pockels cover for switchable control of the reflection from a grounded, isotropic, lossy dielectric slab
Authors: Valagiannopoulos C. A. , Tsitsas N. L. , Lakhtakia A. , Burger A.
Published: February 2015

Theoretical analysis indicates that the reflection of obliquely incident light with arbitrary polarization state in the mid-wavelength (3–8 μm) and long-wavelength (8–15 μm) infrared regimes by a lossy, isotropic, dielectric slab backed by a perfect electric conductor can be electrically controlled by covering the dielectric slab by an epitaxial layer of cubic noncentrosymmetric materials, which are normally isotropic dielectric but display the Pockels effect. The reflectances change on the application of a dc electric field parallel to thickness direction of the Pockels cover, without causing depolarization.
Thermal island destabilization and the Greenwald limit
Authors: White R. B. , Gates D. A. , Brennan D. P.
Published: February 2015

Magnetic reconnection is ubiquitous in the magnetosphere, the solar corona, and in toroidal fusion research discharges. In a fusion device, a magnetic island saturates at a width which produces a minimum in the magnetic energy of the configuration. At saturation, the modified current density profile, a function of the flux in the island, is essentially flat, the growth rate proportional to the difference in the current at the O-point and the X-point. Further modification of the current density profile in the island interior causes a change in the island stability and additional growth or contraction of the saturated island. Because field lines in an island are isolated from the outside plasma, an island can heat or cool preferentially depending on the balance of Ohmic heating and radiation loss in the interior, changing the resistivity and hence the current in the island. A simple model of island destabilization due to radiation cooling of the island is constructed, and the effect of modification of the current within an island is calculated. An additional destabilization effect is described, and it is shown that a small imbalance of heating can lead to exponential growth of the island. A destabilized magnetic island near the plasma edge can lead to plasma loss, and because the radiation is proportional to plasma density and charge, this effect can cause an impurity dependent density limit.
The instability condition of the aperiodic ordinary mode for new scalings of the counterstreaming parameters
Authors: Vafin S. , Lazar M. , Schlickeiser R.
Published: February 2015

The aperiodic ordinary (O-) mode instability in homogeneous and collisionless plasmas with kinetic anisotropies has recently received renewed attention due to its potential application in the solar wind, as well as for equal-mass plasmas. The present paper revisits the marginal instability condition of the O-mode derived from the electromagnetic linear dispersion equation for waves propagating perpendicular to the background magnetic field. For a counterstreaming bi-Maxwellian plasma system, this condition is found to be significantly affected by the streaming parameters. New functional dependencies (not studied before) of the counterstreaming parameters on the magnetic field and the other plasma parameters lead to new conditions of this instability for the both equal mass and electron-proton plasmas.
Atomic-scale observation of dynamical fluctuation and three-dimensional structure of gold clusters
Authors: Li Junjie , Yin Deqiang , Chen Chunlin , Li Qiang , Lin Liyang , Sun Rong , Huang Sumei , Wang Zhongchang
Published: February 2015

Unravelling three-dimensional structures and dynamical fluctuation of metal nanoclusters is critical to understanding reaction process and the origin of catalytic activity in many heterogeneous catalytic systems. We obtain three-dimensional structures of ultra-small Au clusters by combining aberration-corrected scanning transmission electron microscopy, density functional theory calculations, and imaging simulations. The configurations of unique Au clusters are revealed at the atomic scale and the corresponding electronic states are given. The sequential observations reveal a transition of ultra-small Au clusters with about 25 atoms from a near-square to an elongated structure. We also find a transition from two dimensions to three dimensions for the Au clusters. The obtained three-dimensional geometry and associated electronic states help to clarify atomistic mechanism of shape- and number-dependent catalytic activities of Au clusters.
Quantum theory of space charge limited current in solids
Authors: González Gabriel
Published: February 2015

We present a quantum model of space charge limited current transport inside trap-free solids with planar geometry in the mean field approximation. We use a simple transformation which allows us to find the exact analytical solution for the steady state current case. We use our approach to find a Mott-Gurney like behavior and the mobility for single charge carriers in the quantum regime in solids.
Effect of interfacial coupling on photocatalytic performance of large scale MoS2/TiO2 hetero-thin films
Authors: Tao Junguang , Chai Jianwei , Guan Lixiu , Pan Jisheng , Wang Shijie
Published: February 2015

Interface electronic behavior of two-dimensional large scale MoS2/TiO2 hetero-thin films has been studied using photoemission spectroscopy. We show a clear experimental evidence for type II band alignment and upward band bending (∼0.55 eV) at the interface of this system. The valence band offset at monolayer MoS2/TiO2 interface was measured to be 2.15 eV, while the conduction band offset was 1.00 eV. The unique interface band positions introduce a strong build-in electric field for efficient electron-hole separation. In addition, thermal treatment results in better interfacial coupling and charge separation efficiency thus enhanced visible light photoactivity. Our results explicate the mechanism and emphasize its huge potential in visible light photocatalysis.
Misfit strain phase diagrams of epitaxial PMN–PT films
Authors: Khakpash N. , Khassaf H. , Rossetti G. A. , Alpay S. P.
Published: February 2015

Misfit strain–temperature phase diagrams of three compositions of (001) pseudocubic (1 − x)·Pb (Mgl/3Nb2/3)O3 − x·PbTiO3 (PMN–PT) thin films are computed using a phenomenological model. Two (x = 0.30, 0.42) are located near the morphotropic phase boundary (MPB) of bulk PMN–PT at room temperature (RT) and one (x = 0.70) is located far from the MPB. The results show that it is possible to stabilize an adaptive monoclinic phase over a wide range of misfit strains. At RT, the stability region of this phase is much larger for PMN–PT compared to barium strontium titanate and lead zirconate titanate films.
Epoxidation of trans-4-Aminocyclohex-2-en-1-ol Derivatives: Competition of Hydroxy-Directed and Ammonium-Directed Pathways
Authors: Brennan Méabh B. , Davies Stephen G. , Fletcher Ai M. , Lee James A. , Roberts Paul M. , Russell Angela J. , Thomson James E.
Published: February 2015

N-Substituted trans-4-aminocyclohex-2-en-1-ols undergo epoxidation upon treatment with Cl3CCO2H followed by meta-chloroperbenzoic acid (m-CPBA) via competitive pathways resulting from hydrogen-bonding delivery by both the hydroxy group and the in situ formed ammonium ion. The absence of epoxide ring-opening in these reactions renders these substrates a unique platform for analysing the effect of the two competing directing groups on the rate of the epoxidation reaction: the diastereoisomeric ratio of the epoxide products is also the ratio of the rate constants describing the competing epoxidation processes (the group with the higher directing ability dominating the stereochemical course of the reaction). Analysis of the diastereoisomeric epoxide mixtures obtained from these reactions allowed the following order of directing group ability to be defined: NHBn >> NMeBn > OH > NBn2. The large difference in rate between the secondary and tertiary amino groups is consistent with superior directing ability of the former due to the presence of two hydrogen-bond donor sites on the secondary ammonium ion and/or an increased conformational flexibility to adopt an optimum geometry. The rate of an ammonium-directed epoxidation proceeds ~10 times slower in the presence of an allylic hydroxy group than in its absence, consistent with the presence of the additional, inductively electron-withdrawing heteroatom abating the nucleophilicity of the olefin. The relative rate of the hydroxy-directed epoxidation process in the presence of a more sterically demanding ammonium substituent is greater than that in the presence of a less sterically demanding one: this effect is attributed to an increased bias for the half-chair conformer in which the bulky ammonium substituent and, hence, the hydroxy group occupy pseudo-equatorial sites, thus allowing the latter to direct the reaction more efficiently.
N,N-Dialkyl-N′-Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part XI. Some Substitution Reactions of Pyrazolo[1,5-b][1,2,4,6]thiatriazine 1,1-Dioxides
Authors: Norman Rebecca E. , Perkins Michael V. , Liepa Andris J. , Francis Craig L.
Published: February 2015

The recently discovered pyrazolo[1,5-b][1,2,4,6]thiatriazine template was shown to possess four nucleophilic sites (N2, N4, C5, N7) that underwent a range of substitution reactions. Methylation occurred at both N4 and N7. Alkylation with benzylic halides occurred preferentially at N7, regardless of the solvent, but also occurred at C5, N4, and N2. Similar alkylation with α-halo esters occurred at both N4 and N7, but the latter derivatives underwent a novel pyrazole ring expansion to afford pyrimido[1,6-b][1,2,4,6]thiatriazine derivatives. Bromination of pyrazolo[1,5-b][1,2,4,6]thiatriazines afforded unstable 5-bromo derivatives. Tosylation occurred selectively at C5, but in modest yield; catalysis with 1-methylimidazole also led to a low yield of the 5,5′-dimer. The action of HCl on N7-benzylated pyrazolo[1,5-b][1,2,4,6]thiatriazines readily caused extrusion of sulfur dioxide to produce pyrazolo-guanidines.
Synthesis, Structure, and Characterisation of Two New Open-Framework Zinc Phosphites of Varying Dimensionality
Authors: Zhang Xiao , Li Jin-Hua , Wang Guo-Ming , Bao Zhen-Zhen , Zhao Xiao-Meng , Wang Qian , Jiang Wen-Wen
Published: February 2015

Using homopiperazine (hpip) as a structure directing agent, two new zinc phosphites [H2hpip][Zn2(HPO3)3] (1) and [H2hpip][Zn3(HPO3)4] (2), have been synthesised and structurally characterised by IR spectroscopy, elemental analysis, thermogravimetric analysis, and powder and single-crystal X-ray diffractions. Although both compounds are constructed from the same ZnO4 and HPO3 building units, the final frameworks are distinctly different due to their different connectivity. Compound 1 displays a 2D layered structure with 8-membered ring apertures, while compound 2 possesses a (3,4)-connected 3D architecture with multidirectional intersecting 8- and 12-ring channels. In addition, the simultaneous occurrence of four types of 8-ring channels intersecting the large 12-ring apertures in 2 is unique and observed here for the first time.
The economic significance of maintaining pasture production at its peak value
Authors: Ludemann C. I. , Jacobs J. L. , Smith K. F.
Published: February 2015

Persistence of pasture is considered an important trait by many farmers using pasture-based systems. Despite this, pasture persistence is generally poorly defined. This study includes an analysis of changes in farm operating profits (OP) when pasture persistence is improved. Persistence was defined as either a 1-year increase in years at peak dry matter (DM) production or a reduction in the rate of decline in annual pasture DM production after the year that peak production occurred (duration of pasture life), both resulting in a 1-year delay in pasture renovation. Changes in OP for these definitions of pasture persistence were modelled for two dairy farms in temperate regions of Australia (Terang in south-western Victoria and Elliott in Tasmania). An increase in duration of peak DM production on the basis of economic theory increased OP more than an increase in duration of pasture life. Increases in OP for a 1-year increase in peak DM production were AU$165 ha–1 for Terang and $202 ha–1 for Elliott. This compared with $21 ha–1 for Terang and $15 ha–1 for Elliott for a 1-year increase in the duration of pasture life. Therefore, farmers and plant breeders could place more emphasis on improving the duration of time that pasture plants achieve peak DM production than improving pasture persistence at the end of the pasture plant’s lifetime, to increase annual OP.
Marine plastic pollution: using community science to address a global problem
Authors: Duckett Paul. E. , Repaci Vincenzo
Published: February 2015

It was once thought oceans were so vast they could not be affected by humans, but unfortunately rapid globalisation now threatens marine biodiversity. The negative effects of marine debris were recognised in the 1970s, and more recently globally acknowledged in scientific literature. We revisited the Greater Sydney region in New South Wales Australia, to research whether plastic waste on coastal beaches has reduced in recent years. This was achieved by designing a community science project in collaboration with local schools and volunteers. We discovered that plastic debris differed between beaches and strata, but was similar to Australian beaches that were sampled over a decade ago. The high correlations we found between plastic debris and both the frequency of storm-water drains and local population sizes suggested that storm-water drains may be responsible for delivering plastic waste to coastal ecosystems, and the amount of plastic debris was proportional to the size of the surrounding population. Involving local communities has the potential to rapidly raise awareness about key conservation issues to large and broad demographic audiences. Ultimately, this may inspire public and political change.
‘Catching chlamydia’: combining cash incentives and community pharmacy access for increased chlamydia screening, the view of young people
Authors: Parker Rhian M. , Bell Allison , Currie Marian J. , Deeks Louise S. , Cooper Gabrielle , Martin Sarah J. , Del Rosario Rendry , Hocking Jane S. , Bowden Francis J.
Published: February 2015

In Australia and elsewhere, chlamydia screening rates for those aged between 16 and 30 years continue to be low. Innovative, age-appropriate approaches are necessary to increase chlamydia screening among this target group to prevent short- and long-term consequences of the infection such as pelvic inflammatory disease, chronic pelvic pain, ectopic pregnancy and infertility. Studies have demonstrated that offering chlamydia screening in community pharmacies may be a useful adjunct to current screening services. Approximately 90% of Australians visit a pharmacy at least once a year. Chlamydia screening and education in community pharmacies with remuneration may provide another option for opportunistic testing as part of a national chlamydia screening scheme. Compensation is an accepted practice in the field of research and has been demonstrated to improve adherence to health promotion activities. In 2011, a cross-sectional study of community pharmacy-based chlamydia screening offered in conjunction with an A$10 cash incentive to participate was conducted in the Australian Capital Territory. As part of this study young people were asked about their experience of, and views about, pharmacy-based chlamydia screening. The views of consented participants were collected using the one-page questionnaire consisting of 10 closed questions and one open-ended question. Participants completed the questionnaire when they returned their urine sample and before being given the cash incentive. Overall participants were highly satisfied with the pharmacy-based chlamydia screening service. Over 60% of questionnaire respondents felt that the payment did affect their decision to have the chlamydia test, and 23% stated that it made no difference. Young people reported that pharmacy-based screening is acceptable and convenient. Accessibility and the small cash incentive played significant roles in increasing participation.
Oestrous cycle-dependent expression of Fas and Bcl2 family gene products in normal canine endometrium
Authors: Henriques S. , Silva E. , Cruz S. , Silva M. F. , Ferreira-Dias G. , Lopes-da-Costa L. , Mateus L.
Published: February 2015

During the oestrous cycle canine endometrium undergoes cyclical cellular proliferation, apoptosis and differentiation. To study the regulation of endometrial apoptosis and proliferation events the expression of apoptosis-related genes was analysed by real-time polymerase chain reaction and cellular expression of their proteins was identified through immunohistochemistry. Cellular apoptosis and proliferation events were detected by TdT-mediated dUTP-biotin nick end labeling (TUNEL) and proliferation marker Ki67 immunostaining, respectively. The highest proliferative index was observed in the follicular phase (all endometrial cellular components) and at early dioestrus (basal glands). This was associated with a low apoptotic index and a strong expression of anti- (Bcl2) and pro-apoptotic proteins (Fas, FasL, Bax). Subsequently (Days 11–45 of dioestrus), basal glandular epithelium experienced the highest apoptotic index, coincidental with a decrease of Bcl2 expression and a low ratio of Bcl2/Bax transcription. An increase in the apoptotic index of crypts, stromal and endothelial cells was observed at late dioestrus and the beginning of anoestrus. These results indicate that pro- and anti-apoptotic proteins regulate the balance between cell proliferation and death in the canine endometrium during the oestrous cycle. High Bcl2 expression in both the follicular and early dioestrous phases stimulate glandular proliferation and prevent apoptosis but, in the non-pregnant uterus, a decrease in Bcl2 expression together with an increase in pro-apoptotic proteins induces apoptosis of basal glandular epithelium cells.
One-carbon metabolism and epigenetic regulation of embryo development
Authors: Xu Juan , Sinclair Kevin D.
Published: February 2015

One-carbon (1C) metabolism consists of an integrated series of metabolic pathways that include the folate cycle and methionine remethylation and trans-sulfuration pathways. Most, but not all, 1C metabolic enzymes are expressed in somatic cells of the ovary, mammalian oocytes and in preimplantation embryos. The metabolic implications of this, with regard to the provision of methyl donors (e.g. betaine) and 1C cofactors (e.g. vitamin B12), together with consequences of polymorphic variances in genes encoding 1C enzymes, are not fully understood but are the subject of ongoing investigations at the authors’ laboratory. However, deficiencies in 1C-related substrates and/or cofactors during the periconception period are known to lead to epigenetic alterations in DNA and histone methylation in genes that regulate key developmental processes in the embryo. Such epigenetic modifications have been demonstrated to negatively impact on the subsequent health and metabolism of offspring. For this reason, parental nutrition around the time of conception has become a focal point of investigation in many laboratories with the aim of providing improved nutritional advice to couples. These issues are considered in detail in this article, which offers a contemporary overview of the effects of 1C metabolism on epigenetic programming in mammalian gametes and the early embryo.
The effects of passage through the gut of goats and cattle, and the application of dung as a fertiliser on seedling establishment of Dichrostachys cinerea and Acacia nilotica
Authors: Tjelele T. J. , Ward D. , Dziba L. E.
Published: February 2015

Seed pods of Dichrostachys cinerea and Acacia nilotica have higher nutritive value than grasses and other browse plants during the dry season and form an important part of the diet of livestock. Seeds of Acacia may be destroyed during passage through the digestive tract of herbivores whereas seeds of other browse species can remain viable even after mechanical (chewing) and chemical (digestive) scarification. The seedling emergence, seedling establishment and recruitment of D. cinerea and A. nilotica seeds, dispersed by cattle and goats, were measured under natural conditions in the wet and dry seasons following sowing in the dry season. Seeds retrieved from goats and cattle, during the first 3 days and the last 4 days of the recovery period, and control seeds were subjected to the following planting methods: (1) seeds placed on top of the soil with no dung, (2) seeds buried to a depth of 2 cm in the soil with no dung, and (3) seeds buried to a depth of 2 cm in the soil with dung, in the wet and dry seasons. Significantly more A. nilotica and D. cinerea seeds were retrieved from cattle (40.0 ± 3.6% and 25.7 ± 3.9%, respectively), than goats (11.7 ± 3.1% and 13.2 ± 3.8%, respectively). There were significant interactions among animal species, seed-recovery day, planting and season for percentage seedling recruitment. Seedlings from seeds retrieved from goats (12.0 ± 0.06%) had a significantly higher recruitment rate than from seeds retrieved from cattle (7.6 ± 0.05%) and control seeds (i.e. no passage through the gut) (4.1 ± 0.02%). Seedling recruitment rate was higher from seeds recovered from animals in the last 4 days of the recovery period and from D. cinerea than A. nilotica. The planting method of seeds buried to a depth of 2 cm in the soil with no dung had the highest seedling recruitment rate. We conclude that both goats and cattle may facilitate woody plant encroachment by enhancing seedling emergence.
Isolation and characterization of an early colonizing Rhizobium sp. R8 from a household toilet bowl
Authors: Fukano Toru , Gomi Mitsuhiro , Osaki Yukihiko , Morikawa Masaaki
Published: February 2015

The bacterial community structure was compared between the third days’, one week’, and three weeks’ biofilm samples from the surface of a household toilet bowl. It was found that the PCR-DGGE band pattern of 16S rRNA gene was dramatically changed after the third day and was not further changed until three weeks. This result suggests that there are early and late colonizing bacterial groups. One of the early colonizers isolated from the third days’ sample was Rhizobium sp. R8, a closest relative to Rhizobium giardinii, which exhibited the highest biofilm formation activity in an artificial urine condition. R8 produced extracellular polysaccharides containing galactose, glucose, and mannose at the molar ratio of 8:1:1, which were probably responsible for the biofilm formation. Its excelled biofilm formation and urease activities together with the lack of nodulation and nitrogen fixing genes in R8 suggest that this strain has been specifically adapted to urine condition in a toilet bowl.
Why Is the Crowd Divided? Attribution for Dispersion in Online Word of Mouth
Authors: He Stephen X. , Bond Samuel D.
Published: February 2015

The widespread availability of online word of mouth (WOM) enables modern consumers to assess not only the opinions of others about products and services, but also the extent to which those opinions are consistent or dispersive. Despite longstanding calls for greater understanding of mixed opinions, existing evidence is inconclusive regarding effects of WOM dispersion, and theoretical accounts have relied primarily on the notion of reference dependence. Extending prior work, this research proposes an attribution-based account, in which consumer interpretation of WOM dispersion depends on the extent to which tastes in a product domain are perceived to be dissimilar, so that dispersion can be attributed to inconsistency in reviewer preferences rather than the product itself. Across four experimental studies, participants presented with online rating distributions were more tolerant of dispersion in taste-dissimilar product domains than taste-similar product domains, and the difference was driven by underlying attributions. Together, these findings expand current understanding of WOM, social distributions, and risk perception, by revealing distinct pathways through which consumers respond to differences of opinion. In addition, they suggest the opportunity to proactively influence the manner in which dispersion is perceived, highlighting its positive connotations while diminishing its association with risk.
Aflatoxin and Fumonisin in Corn (Zea mays) Infected by Common Smut Ustilago maydis
Authors: Abbas Hamed K. , Zablotowicz Robert M. , Shier W. Thomas , Johnson Bobbie J. , Phillips Nicholas A. , Weaver Mark A. , Abel Craig A. , Bruns H. Arnold
Published: February 2015

Corn infected with Ustilago maydis (common smut) produces galls that are valued as a delicacy in some cultures. During a 4-year period, aflatoxin levels in asymptomatic kernels of smutted ears were, on average, 45-fold higher than in kernels harvested from smut-free control ears and 99-fold higher than in smut galls. Aflatoxin levels in smut galls were lower than in kernels of smut-free control corn in all years combined. Fumonisin levels in asymptomatic kernels harvested from smutted ears were 5.2-fold higher than in kernels from smut-free control ears and 4.0-fold higher than in smut galls. Fumonisin levels in smut galls were not significantly different than in kernels of smut-free control corn. These studies indicate that, although corn smut was relatively free of the mycotoxins studied, the asymptomatic kernels of those ears contained mycotoxins at levels much higher than usually considered safe for direct human consumption.
Maryblyt v. 7.1 for Windows: An Improved Fire Blight Forecasting Program for Apples and Pears
Authors: Turechek William W. , Biggs Alan R.
Published: February 2015

This article describes updates found in Version 7.1 of the fire blight prediction model Maryblyt, originally developed by Paul Steiner and Gary Lightner. In addition, a brief history of the development of the Maryblyt model is given. The article ends with examples comparing the performance of Version 7.1 to Version 4.3c, the last version that was validated and released prior to its upgrade to Maryblyt 7.0 for Windows. We show that Version 7.1 provides results nearly identical to the previously validated DOS version 4.x.

Accepted 22 December 2014. Published 27 January 2015.
Genetic Diversity and Population Structure of Cucurbit Gummy Stem Blight Fungi Based on Microsatellite Markers
Authors: Brewer Marin Talbot , Rath Manisha , Li Hao-Xi
Published: February 2015

Combining population genetics with epidemiology provides insight into the population biology of pathogens, which could lead to improved management of plant diseases. Gummy stem blight, caused by three closely related species of Stagonosporopsis—Stagonosporopsis cucurbitacearum (syn. Didymella bryoniae), S. citrulli, and S. caricae—is a devastating disease of cucurbits worldwide. Sources of inoculum for epidemics, mechanisms of dispersal, and the mating system of these species are not well understood. To improve our knowledge of gummy stem blight epidemiology, we developed 18 polymorphic microsatellite markers by combining microsatellite motif enrichment with next-generation sequencing. When tested on 46 isolates from diverse cucurbit hosts and regions, the markers were robust for the dominant and widely distributed S. citrulli. Within this species, we found no population structure based on broad-scale geographic region or host of origin. Using the microsatellites, a rapid polymerase chain reaction-based method was developed to distinguish the three morphologically similar species causing gummy stem blight. To better understand dispersal, reproduction, and fine-scale genetic diversity of S. citrulli within and among watermelon fields, 155 isolates from two field populations in Georgia, United States were genotyped with the 18 microsatellite loci. Although dominant and widespread clones were detected, we found relatively high genotypic diversity and recombinant genotypes consistent with outcrossing. Significant population genetic structure between the two field populations demonstrated that there is regional geographic structure and limited dispersal among fields. This study provides insight into the fine-scale genetic diversity and reproductive biology of the gummy stem blight pathogen S. citrulli in the field.
Genome-Enabled Phylogeographic Investigation of the Quarantine Pathogen Ralstonia solanacearum Race 3 Biovar 2 and Screening for Sources of Resistance Against Its Core Effectors
Authors: Clarke Christopher R. , Studholme David J. , Hayes Byron , Runde Brendan , Weisberg Alexandra , Cai Rongman , Wroblewski Tadeusz , Daunay Marie-Christine , Wicker Emmanuel , Castillo Jose A. , Vinatzer Boris A.
Published: February 2015

Phylogeographic studies inform about routes of pathogen dissemination and are instrumental for improving import/export controls. Genomes of 17 isolates of the bacterial wilt and potato brown rot pathogen Ralstonia solanacearum race 3 biovar 2 (R3bv2), a Select Agent in the United States, were thus analyzed to get insight into the phylogeography of this pathogen. Thirteen of fourteen isolates from Europe, Africa, and Asia were found to belong to a single clonal lineage while isolates from South America were genetically diverse and tended to carry ancestral alleles at the analyzed genomic loci consistent with a South American origin of R3bv2. The R3bv2 isolates share a core repertoire of 31 type III-secreted effector genes representing excellent candidates to be targeted with resistance genes in breeding programs to develop durable disease resistance. Toward this goal, 27 R3bv2 effectors were tested in eggplant, tomato, pepper, tobacco, and lettuce for induction of a hypersensitive-like response indicative of recognition by cognate resistance receptors. Fifteen effectors, eight of them core effectors, triggered a response in one or more plant species. These genotypes may harbor resistance genes that could be identified and mapped, cloned, and expressed in tomato or potato, for which sources of genetic resistance to R3bv2 are extremely limited.
Crystal structure of trichlorido(4′-ferrocenyl-2,2′:6′,2′′-terpyridine-κ3N,N′,N′′)iridium(III) acetonitrile disolvate
Authors: Davaasuren Bambar , Padhy Harihara , Rothenberger Alexander
Published: February 2015

In the title compound, [FeIr(C5H5)(C20H14N3)Cl3]·2CH3CN, the central IrIIIatom is sixfold coordinated by three chloride ligands and three terpyridine N atoms in a slightly distorted octahedral fashion. The terpyridine ligand is functionalized at the 4′-position with a ferrocenyl group, the latter being in an eclipsed conformation. In the crystal, molecules are stacked in rows parallel to [001], with the acetonitrile solvent molecules situated between the rows. An extensive network of intra- and intermolecular C—H...Cl interactions is present, stabilizing the three-dimensional structure.
Novel psychoactive substances (NPS): clinical and pharmacological issues
Authors: Schifano Fabrizio
Published: February 2015

Purpose

– The purpose of this paper is to provide health professionals with novel psychoactive substances (NPS) clients with up to date information relating to the background, clinical pharmacology and, when possible, clinical management for each of these categories.

Design/methodology/approach

– The world of NPS is complex and diverse, including a range of different molecules such as: psychedelic phenethylamines; synthetic cannabinoids, cathinone derivatives; novel stimulants; synthetic opiates/opioids; tryptamine derivatives; phencyclidine-like dissociatives; piperazines; GABA-A/GABA-B receptor agonists; a range of prescribing medications; psychactive plants/herbs; and a large series of performance and image-enhancing drugs. These molecules are sought by users for their psychactive effects.

Findings

– The NPS categorization and classification provided here is an attempt to identify and better understand some of these substances. Given the vast range of medical and psychopathological issues associated with the NPS described it is crucial for health professionals to be aware of the effects and toxicity of NPS. The EU-MADNESS project aims to both better understand the pharmacology of the available/forthcoming NPS and to disseminate the most current NPS-related information to practising and training health professionals.

Research limitations/implications

– Further studies are required to identify a range of evidence-based, NPS-focused, clinical management and treatment strategies.

Social implications

– The rapid pace of change in the NPS online market constitutes a major challenge to the provision of current and reliable scientific knowledge on these substances.

Originality/value

– The present review will provide an overview of the clinical and pharmacological issues related to a few hundred NPS.