bluuebunny/crossref_metadata_2025 huggingface dataset:
Spin filter and molecular switch based on bowtie-shaped graphene nanoflake
Authors: Kang Jun , Wu Fengmin , Li Jingbo
Published: November 2012

The magnetic and transport properties of bowtie-shaped graphene nanoflake (BGNF) are investigated from first principles calculations. The eigen states of ferromagnetic (FM) BGNF near Fermi level are found to be delocalized over the whole flake, whereas those of antiferromagnetic (AFM) BGNF are localized in one side. The different characters result in different transport properties for FM and AFM BGNFs. FM BGNF exhibits perfect spin filtering effect and can serve as a spin filter. Moreover, the conductance of BGNF is much larger in FM state than in AFM state, thus BGNF can serve as a molecular switch. These results suggest that BGNF is a good candidate for future nanoelectronics.
Characterization of the state of a droplet on a micro-textured silicon wafer using ultrasound
Authors: Saad N. , Dufour R. , Campistron P. , Nassar G. , Carlier J. , Harnois M. , Merheb B. , Boukherroub R. , Senez V. , Gao J. , Thomy V. , Ajaka M. , Nongaillard B.
Published: November 2012

In this work, we propose acoustic characterization as a new method to probe wetting states on a superhydrophobic surface. The analysis of the multiple reflections of a longitudinal acoustic wave from solid-liquid and solid-vapor interfaces enables to distinguish between the two well known Cassie-Baxter and Wenzel wetting configurations. The phenomenon is investigated experimentally on silicon micro-pillars superhydrophobic surfaces and numerically using a finite difference time domain method. Numerical calculations of reflection coefficients show a good agreement with experimental measurements, and the method appears as a promising alternative to optical measurement methods.
A macroscopic model that connects the molar excess entropy of a supercooled liquid near its glass transition temperature to its viscosity
Authors: Matsuoka Hiroshi
Published: November 2012

For a deeply supercooled liquid near its glass transition temperature, we suggest a possible way to connect the temperature dependence of its molar excess entropy to that of its viscosity by constructing a macroscopic model, where the deeply supercooled liquid is assumed to be a mixture of solid-like and liquid-like micro regions. In this model, we assume that the mole fraction x of the liquid-like micro regions tends to zero as the temperature T of the liquid is decreased and extrapolated to a temperature $T_{\rm g}^{\rm *}$Tg*, which we assume to be below but close to the lowest glass transition temperature Tg attainable with the slowest possible cooling rate for the liquid. Without referring to any specific microscopic nature of the solid-like and liquid-like micro regions, we also assume that near Tg, the molar enthalpy of the solid-like micro regions is lower than that of the liquid-like micro regions. We then show that the temperature dependence of x is directly related to that of the molar excess entropy. Close to Tg, we assume that an activated motion of the solid-like micro regions controls the viscosity and that this activated motion is a collective motion involving practically all of the solid-like micro-regions so that the molar activation free energy Δga for the activated motion is proportional to the mole fraction, 1 − x, of the solid-like micro regions. The temperature dependence of the viscosity is thus connected to that of the molar excess entropy se through the temperature dependence of the mole fraction x. As an example, we apply our model to a class of glass formers for which se at temperatures near Tg is well approximated by se ∝ 1 − TK/T with $T_{\rm K} < T_{\rm g} \cong T_{\rm g}^{\rm *}$TK<Tg≅Tg* and find their viscosities to be well approximated by the Vogel-Fulcher-Tamman equation for temperatures very close to Tg. We also find that a parameter a appearing in the temperature dependence of x for a glass former in this class is a measure for its fragility. As this class includes both fragile and strong glass formers, our model applies to both fragile and strong glass formers. We estimate the values of three parameters in our model for three glass formers in this class, o-terphenyl, 3-bromopentane, and Pd40Ni40P20, which is the least fragile among these three. Finally, we also suggest a way to test our assumption about the solid-like and liquid-like micro regions by means of molecular dynamics simulations of model liquids.
Identification of quantum confined interband transitions in type-II InAs/GaSb superlattices using polarization sensitive photocurrent spectroscopy
Authors: Gautam Nutan , Barve Ajit , Krishna Sanjay
Published: November 2012

We report on the use of polarization sensitive photocurrent spectroscopy for identifying the participating transitions in type-II InAs/GaSb strained layer superlattice system. Transverse electric and transverse magnetic photocurrents have been measured for both midwave infrared and longwave infrared superlattices, and prominent features have been analyzed to identify different interband transition energies and unambiguously predict the correct ordering of hole minibands. The interband transition energies have also been confirmed with theoretical simulations using empirical pseudopotential method. Order of the participating valence minibands has been determined as: heavy-hole1, light-hole1 and light-hole2, with increase in hole energy.
Propagation of radiation in fluctuating multiscale plasmas. I. Kinetic theory
Authors: Tyshetskiy Yu. , Pal Singh Kunwar , Thirunavukarasu A. , Robinson P. A. , Cairns Iver H.
Published: November 2012

A theory for propagation of radiation in a large scale plasma with small scale fluctuations is developed using a kinetic description in terms of the probability distribution function of the radiation in space, time, and wavevector space. Large scale effects associated with spatial variations in the plasma density and refractive index of the plasma wave modes and small scale effects such as scattering of radiation by density clumps in fluctuating plasma, spontaneous emission, damping, and mode conversion are included in a multiscale kinetic description of the radiation. Expressions for the Stokes parameters in terms of the probability distribution function of the radiation are used to enable radiation properties such as intensity and polarization to be calculated.
Propagation of radiation in fluctuating multiscale plasmas. II. Kinetic simulations
Authors: Pal Singh Kunwar , Robinson P. A. , Cairns Iver H. , Tyshetskiy Yu.
Published: November 2012

A numerical algorithm is developed and tested that implements the kinetic treatment of electromagnetic radiation propagating through plasmas whose properties have small scale fluctuations, which was developed in a companion paper. This method incorporates the effects of refraction, damping, mode structure, and other aspects of large-scale propagation of electromagnetic waves on the distribution function of quanta in position and wave vector, with small-scale effects of nonuniformities, including scattering and mode conversion approximated as causing drift and diffusion in wave vector. Numerical solution of the kinetic equation yields the distribution function of radiation quanta in space, time, and wave vector. Simulations verify the convergence, accuracy, and speed of the methods used to treat each term in the equation. The simulations also illustrate the main physical effects and place the results in a form that can be used in future applications.
Ion distribution function in a plasma with uniform electric field
Authors: Lampe M. , Röcker T. B. , Joyce G. , Zhdanov S. K. , Ivlev A. V. , Morfill G. E.
Published: November 2012

For a homogeneous partially ionized plasma subject to a uniform electric field E, several methods and models are used to calculate the distribution function f(v) for ions subject to charge-exchange collisions. The exact solution for f(v), based on the energy-dependent cross section for Ar, is obtained by Monte Carlo (MC) simulation. This is compared to the MC results for f(v), based on either a constant cross section σ or a constant collision frequency ν. The constant-σ model is found to accurately represent f(v) for any value of E, whereas the constant-ν results are qualitatively incorrect for large fields. Under the constant-σ assumption, a simple, easily solvable ordinary differential equation is obtained which reproduces the MC results with good accuracy.
Time-delay effect on the bursting of the synchronized state of coupled Hindmarsh-Rose neurons
Authors: Zheng Y. G. , Wang Z. H.
Published: November 2012

The time-delay effect on the bursting of the synchronized state of coupled Hindmarsh-Rose neurons is investigated in this paper. The time-delay influence on the structure of the slow manifold is first studied by using the method of stability switch. And then on the basis of the geometric singular perturbation theory, case studies are given to show that the time delay can suppress the bursting oscillation or lead to more complex dynamics. In particular, the mechanism of the transition from bursting oscillation to relaxation oscillation and to chaotic bursting is stated. Numerical results are given to demonstrate the validity of the analytical results.
Modification of the collective Thomson scattering radiometer in the search for parametric decay on TEXTOR
Authors: Nielsen S. K. , Salewski M. , Bongers W. , Korsholm S. B. , Leipold F. , Meo F. , Michelsen P. , Moseev D. , Oosterbeek J. W. , Stejner M. , Westerhof E.
Published: November 2012

Strong scattering of high-power millimeter waves at 140 GHz has been shown to take place in heating and current-drive experiments at TEXTOR when a tearing mode is present in the plasma. The scattering signal is at present supposed to be generated by the parametric decay instability. Here we describe the heterodyne detection system used to characterize the newly discovered signal measured at TEXTOR, and we present spectral shapes in which the signal can appear under different conditions. The radiation is collected by the receiver through a quasi-optical transmission line that is independent of the electron cyclotron resonance heating transmission line, and so the scattering geometry is variable. The signal is detected with 42 frequency channels ranging from 136 to 142 GHz. We demonstrate that the large signal does not originate from gyrotron spurious radiation. The measured signal agrees well with independent backscattering radiometer data.
Small polaron migration associated multiple dielectric responses of multiferroic DyMnO3 polycrystal in low temperature region
Authors: Yang J. , He J. , Zhu J. Y. , Bai W. , Sun L. , Meng X. J. , Tang X. D. , Duan C.-G. , Rémiens D. , Qiu J. H. , Chu J. H.
Published: November 2012

Utilizing temperature dependent dielectric/impedance spectroscopy, multi-dielectric responses involving two dielectric relaxations (DRs) and two magnetic-order-associated dielectric anomalies were observed in polycrystalline DyMnO3. It is elucidated that both DRs’ dynamics, established in terms of equivalent circuit model and small polaron (SP) theories, are closely linked with localized SP migration features. Namely, low-temperature relaxation process can be attributed to short range polaronic variable-range-hopping induced dipolar-type relaxation in grains, whereas the higher-temperature one is due to Maxwell-Wagner relaxation at grain/grain boundary interfaces, which are governed by SP nearest-neighbor-hopping conduction. Additionally, magnetic-orders-associated dielectric anomalies may be assigned to strong spin-lattice couplings by magnetoelasticity-aroused lattice deformation.
Gate tunable graphene-silicon Ohmic/Schottky contacts
Authors: Chen Chun-Chung , Chang Chia-Chi , Li Zhen , Levi A. F. J. , Cronin Stephen B.
Published: November 2012

We show that the I-V characteristics of graphene-silicon junctions can be actively tuned from rectifying to Ohmic behavior by electrostatically doping the graphene with a polymer electrolyte gate. Under zero applied gate voltage, we observe rectifying I-V characteristics, demonstrating the formation of a Schottky junction at the graphene-silicon interface. Through appropriate gating, the Fermi energy of the graphene can be varied to match the conduction or valence band of silicon, thus forming Ohmic contacts with both n- and p-type silicon. Over the applied gate voltage range, the low bias conductance can be varied by more than three orders of magnitude. By varying the top gate voltage from −4 to +4 V, the Fermi energy of the graphene is shifted between −3.78 and −5.47 eV; a shift of ±0.85 eV from the charge neutrality point. Since the conduction and valence bands of the underlying silicon substrate lie within this range, at −4.01 and −5.13 eV, the Schottky barrier height and depletion width can be decreased to zero for both n- and p-type silicon under the appropriate top gating conditions. I-V characteristics taken under illumination show that the photo-induced current can be increased or decreased based on the graphene-silicon work function difference.
Spin effect on parametric interactions of waves in magnetoplasmas
Authors: Shahid M. , Melrose D. B. , Jamil M. , Murtaza G.
Published: November 2012

The parametric decay instability of upper hybrid wave into low-frequency electromagnetic Shear Alfvén wave and Ordinary mode radiation (O-mode) has been investigated in an electron-ion plasma immersed in the uniform external magnetic field. Incorporating quantum effect due to electron spin, the fluid model has been used to investigate the linear and nonlinear response of the plasma species for three-wave coupling in a magnetoplasma. It is shown that the spin of electrons has considerable effect on the parametric decay of upper hybrid wave into Ordinary mode radiation (O-mode) and Shear Alfvén wave even in classical regime.
Potential of using olive pomace as a source of renewable energy for electricity generation in the Kingdom of Jordan
Authors: Al-Ketan Oraib
Published: November 2012

This paper discusses the potential of using olive pomace as a clean, renewable, and reliable source of energy that has the potential to contribute to the total energy supply of the Kingdom of Jordan. Available data were first compiled on available quantities of this raw material in Jordan, calculating the useful stored energy that can be eventually converted into electricity. The data then were reflected against the energy demand in Jordan. Finally, recommendations on the prospect of this alternative energy source would be made. Statistical data for electricity demand in the Kingdom of Jordan show a growth by around 7.4% in 2010 compared to 2009, and an electric peak load increases by 15%. The Kingdom's local crude oil and natural gas production are contributing only 2.8% of the total energy needs of the country and the rest is being imported, while renewable sources share to the energy mix has not exceeded 2% as of 2010. Therefore, the need for new energy sources is highly imperative.
Size-dependent mechanism of cargo sorting during lysosome-phagosome fusion is controlled by Rab34
Authors: Kasmapour Bahram , Gronow Achim , Bleck Christopher K. E. , Hong Wanjin , Gutierrez Maximiliano Gabriel
Published: November 2012

Phagosome maturation is an essential part of the innate and adaptive immune response. Although it is well established that several Ras-related proteins in brain (Rab) proteins become associated to phagosomes, little is known about how these phagosomal Rab proteins influence phagosome maturation. Here, we show a specific role for Rab34 and mammalian uncoordinated 13-2 (Munc13-2) in phagolysosome biogenesis and cargo delivery. Rab34 knockdown impaired the fusion of phagosomes with late endosomes/lysosomes and high levels of active Rab34 promoted this process. We demonstrate that Rab34 enhances phagosome maturation independently of Rab7 and coordinates phagolysosome biogenesis through size-selective transfer of late endosomal/lysosomal cargo into phagosomes. More importantly, we show that Rab34 mediates phagosome maturation through the recruitment of the protein Munc13-2. Finally, we report that the alternative maturation pathway controlled by Rab34 is critical for mycobacterial killing because Rab34 silencing resulted in mycobacterial survival, and Rab34 expression led to mycobacterial killing. Altogether, our studies uncover Rab34/Munc13-2 as a critical part of an alternative Rab7-independent phagosome maturation machinery and lysosome-mediated killing of mycobacteria.
Innate immune response to homologous rotavirus infection in the small intestinal villous epithelium at single-cell resolution
Authors: Sen Adrish , Rothenberg Michael E. , Mukherjee Gourab , Feng Ningguo , Kalisky Tomer , Nair Nitya , Johnstone Iain M. , Clarke Michael F. , Greenberg Harry B.
Published: November 2012

“Bulk” measurements of antiviral innate immune responses from pooled cells yield averaged signals and do not reveal underlying signaling heterogeneity in infected and bystander single cells. We examined such heterogeneity in the small intestine during rotavirus (RV) infection. Murine RV EW robustly activated type I IFNs and several antiviral genes (IFN-stimulated genes) in the intestine by bulk analysis, the source of induced IFNs primarily being hematopoietic cells. Flow cytometry and microfluidics-based single-cell multiplex RT-PCR allowed dissection of IFN responses in single RV-infected and bystander intestinal epithelial cells (IECs). EW replicates in IEC subsets differing in their basal type I IFN transcription and induces IRF3-dependent and IRF3-augmented transcription, but not NF-κB–dependent or type I IFN transcripts. Bystander cells did not display enhanced type I IFN transcription but had elevated levels of certain IFN-stimulated genes, presumably in response to exogenous IFNs secreted from immune cells. Comparison of IRF3 and NF-κB induction in STAT1−/−mice revealed that murine but not simian RRV mediated accumulation of IkB-α protein and decreased transcription of NF-κB–dependent genes. RRV replication was significantly rescued in IFN types I and II, as well as STAT1 (IFN types I, II, and III) deficient mice in contrast to EW, which was only modestly sensitive to IFNs I and II. Resolution of “averaged” innate immune responses in single IECs thus revealed unexpected heterogeneity in both the induction and subversion of early host antiviral immunity, which modulated host range.
SCG10 is a JNK target in the axonal degeneration pathway
Authors: Shin Jung Eun , Miller Bradley R. , Babetto Elisabetta , Cho Yongcheol , Sasaki Yo , Qayum Shehzad , Russler Emilie V. , Cavalli Valeria , Milbrandt Jeffrey , DiAntonio Aaron
Published: November 2012

Axons actively self-destruct following genetic, mechanical, metabolic, and toxic insults, but the mechanism of axonal degeneration is poorly understood. The JNK pathway promotes axonal degeneration shortly after axonal injury, hours before irreversible axon fragmentation ensues. Inhibition of JNK activity during this period delays axonal degeneration, but critical JNK substrates that facilitate axon degeneration are unknown. Here we show that superior cervical ganglion 10 (SCG10), an axonal JNK substrate, is lost rapidly from mouse dorsal root ganglion axons following axotomy. SCG10 loss precedes axon fragmentation and occurs selectively in the axon segments distal to transection that are destined to degenerate. Rapid SCG10 loss after injury requires JNK activity. The JNK phosphorylation sites on SCG10 are required for its rapid degradation, suggesting that direct JNK phosphorylation targets SCG10 for degradation. We present a mechanism for the selective loss of SCG10 distal to the injury site. In healthy axons, SCG10 undergoes rapid JNK-dependent degradation and is replenished by fast axonal transport. Injury blocks axonal transport and the delivery of SCG10, leading to the selective loss of the labile SCG10 distal to the injury site. SCG10 loss is functionally important: Knocking down SCG10 accelerates axon fragmentation, whereas experimentally maintaining SCG10 after injury promotes mitochondrial movement and delays axonal degeneration. Taken together, these data support the model that SCG10 is an axonal-maintenance factor whose loss is permissive for execution of the injury-induced axonal degeneration program.
Defining and predicting structurally conserved regions in protein superfamilies
Authors: Huang Ivan K. , Pei Jimin , Grishin Nick V.
Published: November 2012

Motivation: The structures of homologous proteins are generally better conserved than their sequences. This phenomenon is demonstrated by the prevalence of structurally conserved regions (SCRs) even in highly divergent protein families. Defining SCRs requires the comparison of two or more homologous structures and is affected by their availability and divergence, and our ability to deduce structurally equivalent positions among them. In the absence of multiple homologous structures, it is necessary to predict SCRs of a protein using information from only a set of homologous sequences and (if available) a single structure. Accurate SCR predictions can benefit homology modelling and sequence alignment.

Results: Using pairwise DaliLite alignments among a set of homologous structures, we devised a simple measure of structural conservation, termed structural conservation index (SCI). SCI was used to distinguish SCRs from non-SCRs. A database of SCRs was compiled from 386 SCOP superfamilies containing 6489 protein domains. Artificial neural networks were then trained to predict SCRs with various features deduced from a single structure and homologous sequences. Assessment of the predictions via a 5-fold cross-validation method revealed that predictions based on features derived from a single structure perform similarly to ones based on homologous sequences, while combining sequence and structural features was optimal in terms of accuracy (0.755) and Matthews correlation coefficient (0.476). These results suggest that even without information from multiple structures, it is still possible to effectively predict SCRs for a protein. Finally, inspection of the structures with the worst predictions pinpoints difficulties in SCR definitions.

Availability: The SCR database and the prediction server can be found at http://prodata.swmed.edu/SCR.

Contact:  91huangi@gmail.com or grishin@chop.swmed.edu

Supplementary information:  Supplementary data are available at Bioinformatics Online
Concerning the accuracy of Fido and parameter choice
Authors: Serang Oliver
Published: November 2012

Contact:  Oliver.Serang@Childrens.Harvard.edu
The Ginibre Ensemble and Gaussian Analytic Functions
Authors: Krishnapur Manjunath , Virág Bálint
Published: November 2012

We show that as n changes, the characteristic polynomial of the n×n random matrix with i.i.d. complex Gaussian entries can be described recursively through a process analogous to Pólya’s urn scheme. As a result, we get a random analytic function in the limit, which is given by a mixture of Gaussian analytic functions. This suggests another reason why the zeros of Gaussian analytic functions and the Ginibre ensemble exhibit similar local repulsion, but different global behavior. Our approach gives new explicit formulas for the limiting analytic function.
MHD modelling of a disc wind from a high-mass protobinary: the case of Orion Source I
Authors: Vaidya B. , Goddi C.
Published: November 2012

Very Long Baseline Interferometry (VLBI) observations of SiO masers in Orion Source I has enabled for the first time to resolve the outflow from a high-mass protostar in the launch and collimation region. Therefore, Source I provides a unique laboratory to study mass loss and mass accretion in a high-mass protostar. We numerically simulate the dynamics of the disc wind inside 100 au from Source I. This enables us to investigate the balance of different forces (gravitational, magnetic, thermal) regulating gas dynamics in massive star formation. In this work, we adopt magnetohydrodynamic (MHD) disc-wind models to explain the observed properties of the disc wind from Orion Source I. The central source is assumed to be a binary composed of two 10 M⊙ stars in a circular orbit with an orbital separation of 7 au. High-resolution ideal MHD wind-launching simulations (which prescribe disc as a boundary) are performed using the pluto code. The simulations are allowed to run until a steady state is obtained. MHD-driven disc wind provides a consistent model for the wide-angle flow from Source I probed by SiO masers, reproducing the bipolar morphology, the velocity amplitude and rotational profile, the physical conditions, and the magnetic field strength.
On the magnetic fields in voids
Authors: Beck A. M. , Hanasz M. , Lesch H. , Remus R.-S. , Stasyszyn F. A.
Published: November 2012

We study the possible magnetization of cosmic voids by void galaxies. Recently, observations revealed isolated star-forming galaxies within the voids. Furthermore, a major fraction of a voids volume is expected to be filled with magnetic fields of a minimum strength of about 10−15 G on Mpc scales. We estimate the transport of magnetic energy by cosmic rays (CR) from the void galaxies into the voids. We assume that CRs and winds are able to leave small isolated void galaxies shortly after they assembled, and then propagate within the voids. For a typical void, we estimate the magnetic field strength and volume-filling factor depending on its void galaxy population and possible contributions of strong active galactic nuclei (AGNs) which border the voids. We argue that the lower limit on the void magnetic field can be recovered, if a small fraction of the magnetic energy contained in the void galaxies or void bordering AGNs is distributed within the voids.
Effective international expansion strategies of emerging countries: the strategies that helped Arçelik
Authors: Gülsoy Tanses , Özkanlı Özlem , Lynch Richard
Published: November 2012

Purpose

This paper aims to present the case study of Arçelik, which has become Turkey's leading manufacturer and exporter of home appliances, as a means of offering insight into why, how and with what results companies from developing countries expand internationally.

Design/methodology/approach

Primary data have been drawn from in‐depth interviews conducted with senior executives and industry experts, and this has been based on a statistical analysis of the export and international strategies of Turkish home appliance and television set industry.

Findings

The evidence indicates that international expansion may buffer a firm against fluctuations of demand in its home market and provide opportunities for growth. Difficulties faced by a later arrival from a developing country are greater than established rivals, and a developing country firm will have to rely on different resources and different operational strategies in developed vs developing markets.

Research limitations/implications

Even though one case cannot yield general conclusions, it may indicate fruitful theoretical directions. This study raises issues worthy of further investigation. On the outset, it would be useful to apply the four propositions to more Turkish MNEs in order to test the robustness of the conclusions.

Practical implications

The study has important implications for companies from developing countries. First, international expansion appears to be a viable means of offsetting home‐market volatility for emerging‐country firms. Second, international expansion is still predicated on significant investments in firm‐specific advantages and their development may shorten the internationalization process.

Originality/value

The report contributes to knowledge in the area of international expansion of companies from developing countries by providing evidence on how one company has achieved a world position in a highly competitive market through selective use of quality, innovation, and branding based on the competitive position that is available in each of its chosen markets. In particular, it contributes to the limited evidence on the international expansion of Turkish companies at the present time.
Promoting early detection of psychosis: the role of community outreach
Authors: Joly Brenda , Pukstas Bernard Kimberly , Elbaum Williamson Martha , Mittal Prashant
Published: November 2012

Purpose

The purpose of this paper is to determine the effectiveness of community outreach efforts in promoting public education on the early warning signs of psychosis and in generating referrals for treatment during the prodromal stage of illness.

Design/methodology/approach

Five mental health centres across the United States implemented a community outreach model known as the Early Detection and Intervention for the Prevention of Psychosis Program (EDIPPP). A multi‐site evaluation was conducted to assess whether the model's outreach objectives could be achieved among replication sites in geographically and demographically diverse locations. The assessment included the analysis of data from three main sources: administrative data, structured qualitative interviews, and participant self‐report surveys.

Findings

Results demonstrated that the outreach activities in all five sites resulted in increased awareness of participants about the early warning signs of psychosis, the availability of local treatment options and increased knowledge of the referral process. There were benefits of outreach participation regardless of whether the participant was a professional or non‐professional in the community. Additionally, outreach participants showed a significant increase in their likelihood to refer a young adult for a mental health evaluation.

Originality/value

Community outreach can be an effective tool for mental health centres in developing a local network that can generate timely referrals for early intervention programmes and clinical research. Results also show that relatively brief community engagement efforts can significantly increase the knowledge and awareness of the public on complex mental health conditions where early detection may be integral to effective treatment.
Positive phenotypic correlations among life‐history traits remain in the absence of differential resource ingestion
Authors: Olijnyk Adriana M. , Nelson William A.
Published: November 2012

A central tenet of life‐history theory states that individuals are constrained from maximizing all aspects of fitness simultaneously through negative correlations among life‐history traits, known as trade‐offs. Although evidence for trade‐offs is abundant, a surprising number of taxa reveal positive correlations where trade‐offs are expected.

Previous studies suggest two mechanisms to explain the lack of trade‐offs in situations where they are predicted by theory: differential resource acquisition and multidimensional trait constraints expressed in the presence of genetic variation. However, there is no direct empirical evidence supporting either hypothesis.

Using individuals from multiple genotypes of the cyclic parthenogenic freshwater zooplankton, Daphnia pulicaria, we conducted life‐history experiments that prevented two key aspects of these mechanisms from operating. The experiments were conducted under a range of resources from levels causing near‐starvation to levels of resource abundance yielding a mean clutch size of 4–5 eggs. Growth, reproduction and survival were measured for each individual.

Contrary to expectations, we found strong positive correlations among life‐history traits in the absence of both differential resource ingestion, which is one form of differential resource acquisition, and genetic variation. These positive correlations emerge from differential resource utilization, which is one of the steps along the resource ingestion‐utilization‐allocation pathway.

Our results demonstrate that strong positive correlations among life‐history traits emerge from variation among individuals in an underappreciated aspect of their energy budget. This alternative mechanism has different implications for understanding life‐history evolution, and reinforces the potential role that physiological ecology has in shaping life‐history trait correlations.
Disrupted fine‐scale population processes in fragmented landscapes despite large‐scale genetic connectivity for a widespread and common cooperative breeder: the superb fairy‐wren (Malurus cyaneus)
Authors: Harrisson Katherine A. , Pavlova Alexandra , Amos J. Nevil , Takeuchi Naoko , Lill Alan , Radford James Q. , Sunnucks Paul
Published: November 2012

Understanding how habitat fragmentation affects population processes (e.g. dispersal) at different spatial scales is of critical importance to conservation. We assessed the effects of habitat fragmentation on dispersal and regional and fine‐scale population structure in a currently widespread and common cooperatively breeding bird species found across south‐eastern Australia, the superb fairy‐wren Malurus cyaneus.

Despite its relative abundance and classification as an urban tolerant species, the superb fairy‐wren has declined disproportionately from low tree‐cover agricultural landscapes across the Box‐Ironbark region of north‐central Victoria, Australia. Loss of genetic connectivity and disruption to its complex social system may be associated with the decline of this species from apparently suitable habitat in landscapes with low levels of tree cover.

To assess whether reduced structural connectivity has had negative consequences for genetic connectivity in the superb fairy‐wren, we used a landscape‐scale approach to compare patterns of genetic diversity and gene flow at large (landscape/regional) and fine (site‐level) spatial scales. In addition, using genetic distances, for each sex, we tested landscape models of decreased dispersal through treeless areas (isolation‐by‐resistance) while controlling for the effect of isolation‐by‐distance.

Landscape models indicated that larger‐scale gene flow across the Box‐Ironbark region was constrained by distance rather than by lack of structural connectivity. Nonetheless, a pattern of isolation‐by‐resistance for males (the less‐dispersive sex) and lower genetic diversity and higher genetic similarity within sites in low‐cover fragmented landscapes indicated disruption to fine‐scale gene flow mechanisms and/or mating systems.

Although loss of structural connectivity did not appear to impede gene flow at larger spatial scales, fragmentation appeared to affect fine‐scale population processes (e.g. local gene flow mechanisms and/or mating systems) adversely and may contribute to the decline of superb fairy‐wrens in fragmented landscapes in the Box‐Ironbark region.
The nutrient supplying capabilities of Uzinura, an endosymbiont of armoured scale insects
Authors: Sabree Zakee L. , Huang Charlie Y. , Okusu Akiko , Moran Nancy A. , Normark Benjamin B.
Published: November 2012

An emerging common physiological feature of plant sap‐feeding insects is the presence of bacterial endosymbionts capable of providing essential nutrients to their host. These microbial partners are inviable outside of specialized host tissues, and therefore a cultivation‐independent approach, namely high‐throughput next‐generation genome sequencing, can be used to characterize their gene content and metabolic potential. To this end, we sequenced the first complete genome of the obligate endosymbiont, Candidatus ‘Uzinura diaspidicola’, of armoured scale insects. At 263 431 bp, Uzinura has an extremely reduced genome that is composed largely of genes encoding enzymes involved in translation and amino acid biosynthesis. The tiny size of the Uzinura genome parallels that observed in some other insect endosymbionts. Despite this extreme genome reduction, the absence of a known obligate partner bacterial symbiont suggests that Uzinura alone can supply sufficient nutrients to its host.
Personal and psychosocial predictors of psychological abuse by partners during and after pregnancy: a longitudinal cohort study in a community sample
Authors: Escribà‐Agüir V , Royo‐Marqués M , Artazcoz L , Romito P , Ruiz‐Pérez I , Martín‐Baena D
Published: November 2012

Objective

To describe the incidence and risk factors of psychological intimate partner violence (IPV) during pregnancy and the first year after childbirth.

Design

Longitudinal cohort study.

Setting

Nine primary care centers in the Valencia Region (Spain).

Population

A consecutive sample of 1400 women in the first trimester of pregnancy, attending the prenatal programme in the Valencia Region of Spain in 2008, with follow‐up in the third trimester of pregnancy, and at 5 and 12 months postpartum. A total of 888 women (66.5%) participated in all four phases.

Methods

A logistic regression model was fitted using generalised estimating equations to assess the effects of previous partner violence, consumption of alcohol or illicit drugs and social support on subsequent psychological partner violence.

Main outcome measure

Psychological IPV during follow‐up.

Results

We observed an increase in the incidence of psychological IPV after birth, particularly at 5 months postpartum. The strongest predictor of psychological IPV was having experienced abuse 12 months before pregnancy (OR 10.46, 95%CI 2.40–45.61). Other predictors were consumption of alcohol or illicit drugs by the partner or a family member (OR3.50, 95%CI 1.38–8.85) and lack of affective social support (OR2.83, 95%CI 1.31–6.11).

Conclusions

Previous abuse and psychosocial risk factors predict partner psychological abuse after birth. Monitoring psychological IPV and effective interventions are needed not only during pregnancy but also during the postpartum period.
Mid‐gestational maternal cardiovascular profile in preterm and term pre‐eclampsia: a prospective study
Authors: Melchiorre K , Sutherland G , Sharma R , Nanni M , Thilaganathan B
Published: November 2012

Objective

Pre‐eclampsia (PE) is associated with maternal cardiac remodelling and biventricular diastolic dysfunction. Preterm PE alone can also be associated with severe left ventricular hypertrophy and biventricular systolic dysfunction. The aim of this study was to assess whether the maternal cardiovascular profile at mid‐gestation in nulliparous normotensive women differs in women destined to develop preterm PE versus those who will develop PE at term.

Design

Prospective study.

Setting

Tertiary referral university centre.

Population

A total of 269 women, including 152 at increased risk of developing PE as determined by mid‐gestational uterine artery Doppler assessment.

Methods

Women underwent blood pressure profiling, echocardio‐graphy, cardiac tissue Doppler and strain rate analysis at 20–23 weeks of gestation.

Main outcome measures

Mid‐gestational cardiovascular profile in women with normal pregnancy and those that subsequently developed preterm or term PE.

Results

Pre‐eclampsia subsequently developed in 46 women, including 18 with preterm PE. Women who subsequently developed PE, irrespective of gestation, had evidence of left ventricular concentric remodelling (33%) which was not found in the control women (P < 0.0001). Only women who developed preterm PE exhibited a high resistance‐low volume haemodynamic state at mid‐gestation. The latter group also had evidence of left ventricular diastolic or systolic dysfunction (33%) and segmental impaired myocardial relaxation (72%).

Conclusions

Asymptomatic cardiac diastolic dysfunction is evident at mid‐gestation in women who subsequently develop preterm PE but not in those who develop term PE. These cardiac findings are useful in understanding the pathophysiology of PE and corroborate the concept that PE is not a single disorder, but a cluster of symptoms that have several different aetiologies.
Self‐hypnosis for coping with labour pain: a randomised controlled trial
Authors: Werner A , Uldbjerg N , Zachariae R , Rosen G , Nohr EA
Published: November 2012

Objective

To estimate the use of epidural analgesia and experienced pain during childbirth after a short antenatal training course in self‐hypnosis to ease childbirth.

Design

Randomised, controlled, single‐blinded trial using a three‐arm design.

Setting

Aarhus University Hospital Skejby in Denmark during the period July 2009 until August 2011.

Population

A total of 1222 healthy nulliparous women.

Method

Use of epidural analgesia and self‐reported pain during delivery was compared in three groups: a hypnosis group receiving three 1‐hour lessons in self‐hypnosis with additional audiorecordings to ease childbirth, a relaxation group receiving three 1‐hour lessons in various relaxation methods and mindfulness with audiorecordings for additional training, and a usual care group receiving ordinary antenatal care only.

Main outcome measures

Primary outcome: Use of epidural analgesia. Secondary outcomes included self‐reported pain.

Results

There were no between‐group differences in use of epidural analgesia—31.2% (95% confidence interval [95% CI] 27.1–35.3) in the hypnosis group, 29.8% (95% CI 25.7–33.8) in the relaxation group and 30.0% (95% CI 24.0–36.0) in the control group. No statistically significant differences between the three groups were observed for any of the self‐reported pain measures.

Conclusion

In this large randomised controlled trial of a brief course in self‐hypnosis to ease childbirth, no differences in use of epidural analgesia or pain experience were found across study groups. Before turning down self‐hypnosis as a method for pain relief, further studies are warranted with focus on specific subgroups.
Purification and characterization of prophenoloxidase from cotton bollworm, Helicoverpa armigera
Authors: Goudru Hanumanth G. , Kumar Sathish , Jayalakshmi Senigala K. , Ballal Chandish R. , Sharma Hari C. , Sreeramulu Kuruba
Published: November 2012

Phenoloxidases are oxidative enzymes, which play an important role in both cell mediated and humoral immunity. Purification and biochemical characterization of prophenoloxidase from cotton bollworm, Helicoverpa armigera (Hübner) were carried out to study its biochemical properties. Prophenoloxidase consists of a single polypeptide chain with a relative molecular weight of 85 kDa as determined by SDS–PAGE, MALDI–TOF MS and LC–ESI MS. After the final step, the enzyme showed 71.7 fold of purification with a recovery of 49.2%. Purified prophenoloxidase showed high specific activity and homology with phenoloxidase subunit‐1 of Bombyx mori and the conserved regions of copper binding (B) site of phenoloxidase. Purified prophenoloxidase has pH optima of 6.8 and has high catalytic efficiency towards the dopamine as a substrate in comparison to catechol and L‐Dopa. The PO activity was strongly inhibited by phenylthiourea, thiourea, dithiothreitol and kojic acid.
Positive correlation between chronic hyperglycemia and serum fetuin‐A levels in middle‐aged and elderly Chinese
Authors: Liu Yu , Xu Min , Xu Yu , Li Mian , Wang Tiange , Chen Yuhong , Bi Yufang
Published: November 2012

Background:  The aim of the present study was to evaluate the association between HbA1c and serum fetuin‐A levels in middle‐aged and elderly Chinese.

Methods:  A total of 3790 subjects (1519 men; 2271 women) aged ≥40 years were enrolled in this cross‐sectional study in the Songnan community of Baoshan District, Shanghai, China. HbA1c levels were used to determine the presence of chronic hyperglycemia. Subjects were divided into three groups based on HbA1c levels: <6.5%, 6.5% ≤ HbA1c < 7.0%, and HbA1c ≥ 7.0%. “Elevated” fetuin‐A levels were defined as serum levels in the upper quartile (i.e. ≥367.39 mg/L).

Results:  Mean serum fetuin‐A levels were higher in subjects with HbA1c ≥ 7.0% compared with those in whom HbA1c was <6.5% (309.32 vs 290.83 mg/L, respectively). Multivariate linear regression analysis revealed a significant positive correlation between HbA1c and serum fetuin‐A levels (β = 0.07; SE = 0.03; P = 0.04). After adjustment for possible confounders, an increased percentage of subjects with elevated fetuin‐A levels was found in the group with HbA1c ≥ 7.0% compared with the group in which HbA1c was <6.5% (odds ratio 1.38; 95% confidence interval 1.09–1.74). Interactions were found between HbA1c and both insulin resistance and the urinary albumin‐to‐creatinine ratio for the percentage of elevated fetuin‐A levels (Pinteraction = 0.002 and 0.05, respectively).

Conclusions:  In Chinese adults, a positive correlation was found between chronic hyperglycemia and serum fetuin‐A levels. Further research into the mechanisms underlying fetuin‐A regulation is needed to identify potential drug targets.
Nondestructive DNA sampling from bumblebee faeces
Authors: Scriven Jessica J. , Woodall Lucy C. , Goulson Dave
Published: November 2012

Genetic studies provide valuable data to inform conservation strategies for species with small or declining populations. In these circumstances, obtaining DNA samples without harming the study organisms is highly desirable. Excrements are increasingly being used as a source of DNA in such studies, but such approaches have rarely been applied to arthropods. Bumblebees are ecologically and economically important as pollinators; however, some species have recently suffered severe declines and range contractions across much of Western Europe and North America. We investigated whether bumblebee faeces could be used for the extraction of DNA suitable for genotyping using microsatellite markers. We found that DNA could be extracted using a Chelex method from faecal samples collected either in microcapillary tubes or on filter paper, directly from captured individuals. Our results show that genotypes scored from faecal samples are identical to those from tissue samples. This study describes a reliable, consistent and efficient noninvasive method of obtaining DNA from bumblebees for use in population genetic studies. This approach should prove particularly useful in breeding and conservation programs for bumblebees and may be broadly applicable across insect taxa.
Population structure and ecology of the African buffalo (Syncerus caffer Sparrman, 1779) in Chebera Churchura National Park, Ethiopia
Authors: Megaze Aberham , Belay Gurja , Balakrishnan Mundanthra
Published: November 2012

An investigation of population structure and ecology of the African buffalo (Syncerus caffer Sparrman, 1779) was carried out in the Chebera Churchura National Park, Ethiopia during the wet and dry seasons of 2005–2006. Sample counts of African buffaloes were carried out in an area of 1,215 km2. The estimated population of buffalo was 2,617 individuals. Males comprised 35.0%, while females 52.8% of the population. The remaining 12% of the population was young of both sexes and of all ages of unknown sex. It was difficult to categorize the young into male and female in the field, as their primary sexual characteristics were not easily visible. Male to female sex ratio was 1.00 : 1.51. Age structure was dominated by adults, which constituted 72.06% of the total population. Subadults comprised 22.02%, and young accounted for 5.9% of the population. Larger herds of up to 27 individuals were observed during the wet season and smaller herds of eight individuals during the dry season. The mean herd size during wet and dry seasons was 24.81 and 7.77, respectively. The African buffaloes were distributed in four habitat types such as grasslands, woodlands, montane forests and riverine habitat in the study area. They were observed more in the riverine vegetation types during the dry season. Relative abundance of food resources, green vegetation cover and water availability in the area were the major factors governing their distribution in the present study area. They spent a greater proportion of the time in feeding and resting/ruminating activities. On the average, 49.7% of the daytime was spent in feeding, and 38.75% of the day on resting (lying down and standing). Morning and the late afternoon activity peaks were more pronounced during the dry season than the wet season.