bluuebunny/crossref_metadata_2025 huggingface dataset:
Visible and near-infrared imaging spectrometer and its preliminary results from the Chang’E 3 project
Authors: He Z. P. , Wang B. Y. , Lv G. , Li C. L. , Yuan L. Y. , Xu R. , Chen K. , Wang J. Y.
Published: August 2014

In order to conduct lunar surface mineral composition studies and content analysis, the Visible and Near-infrared Imaging Spectrometer (VNIS), one of the scientific payloads of the Chang’E 3 Yutu rover, has been developed to detect lunar surface objects and to obtain their reflectance spectra and geometric images. This is achieved with a 45° visual angle and at a height of 0.69 m. VNIS is equipped with a lunar surface calibration function, and the spectral range is 0.45–2.40 μm with a spectral resolution of 2–12 nm. It is capable of synchronously acquiring the full spectrum of lunar surface objects and in situ calibration. Here, we describe the VNIS and explain the preliminary results of the lunar surface exploration and calibration, which provides valuable information for scientific data processing and applications.
Terahertz generation by mixing of two super-Gaussian laser beams in collisional plasma
Authors: Singh Divya , Malik Hitendra K.
Published: August 2014

Considering a realistic situation, where electron-neutral collisions persist in plasma, analytical calculations are carried out for the Terahertz (THz) radiation generation by beating of two Super-Gaussian (SG) lasers of index p. The competency of these lasers over Gaussian lasers is discussed in detail with respect to the effects of collision and beam width on the THz field amplitude and efficiency of the mechanism. A critical transverse distance of the peak of the THz field is defined that shows a dependence on the index of SG lasers. Although electron-neutral collisions and larger beam width lead to the drastic reduction in the THz field when the SG lasers are used in the plasma, the efficiency of the mechanism remains much larger than the case of Gaussian lasers. Moreover, the higher index SG lasers produce stronger and focused THz radiation.
Three-dimensional dust-ion-acoustic rogue waves in a magnetized dusty pair-ion plasma with nonthermal nonextensive electrons and opposite polarity dust grains
Authors: Guo Shimin , Mei Liquan
Published: August 2014

Dust-ion-acoustic (DIA) rogue waves are investigated in a three-dimensional magnetized plasma containing nonthermal electrons featuring Tsallis distribution, both positive and negative ions, and immobile dust grains having both positive and negative charges. Via the reductive perturbation method, a (3 + 1)-dimensional nonlinear Schrödinger (NLS) equation is derived to govern the dynamics of the DIA wave packets. The modulation instability of DIA waves described by the (3 + 1)-dimensional NLS equation is investigated. By means of the similarity transformation and symbolic computation, both the first- and second-order rogue wave solutions of the (3 + 1)-dimensional NLS equation are constructed in terms of rational functions. Moreover, the dynamics properties and the effects of plasma parameters on the nonlinear structures of rogue waves are discussed in detail. The results could be useful for understanding the physical mechanism of rogue waves in laboratory experiments where pair-ion plasmas with electrons and dust grains can be found.
Optimizing laser produced plasmas for efficient extreme ultraviolet and soft X-ray light sources
Authors: Sizyuk Tatyana , Hassanein Ahmed
Published: August 2014

Photon sources produced by laser beams with moderate laser intensities, up to 1014 W/cm2, are being developed for many industrial applications. The performance requirements for high volume manufacture devices necessitate extensive experimental research supported by theoretical plasma analysis and modeling predictions. We simulated laser produced plasma sources currently being developed for several applications such as extreme ultraviolet lithography using 13.5% ± 1% nm bandwidth, possibly beyond extreme ultraviolet lithography using 6.× nm wavelengths, and water-window microscopy utilizing 2.48 nm (La-α) and 2.88 nm (He-α) emission. We comprehensively modeled plasma evolution from solid/liquid tin, gadolinium, and nitrogen targets as three promising materials for the above described sources, respectively. Results of our analysis for plasma characteristics during the entire course of plasma evolution showed the dependence of source conversion efficiency (CE), i.e., laser energy to photons at the desired wavelength, on plasma electron density gradient. Our results showed that utilizing laser intensities which produce hotter plasma than the optimum emission temperatures allows increasing CE for all considered sources that, however, restricted by the reabsorption processes around the main emission region and this restriction is especially actual for the 6.× nm sources.
Reversing ferroelectric polarization in multiferroic DyMn2O5 by nonmagnetic Al substitution of Mn
Authors: Zhao Z. Y. , Liu M. F. , Li X. , Wang J. X. , Yan Z. B. , Wang K. F. , Liu J.-M.
Published: August 2014

The multiferroic RMn2O5 family, where R is rare-earth ion or Y, exhibits rich physics of multiferroicity which has not yet well understood. DyMn2O5 is a representative member of this family. The ferroelectric polarization of DyMn2O5 is claimed to be magnetically relevant and have more than one component. Therefore, the polarization reversal upon the sequent magnetic transitions is expected. We investigate the evolution of the ferroelectric polarization upon a partial substitution of Mn3+ by nonmagnetic Al3+ in order to tailor the Mn3+-Mn4+ interactions and then to modulate the polarization in DyMn2−x/2Alx/2O5. It is revealed that the polarization can be successfully reversed by Al-substitution via substantially suppressing the Mn3+-Mn4+ interactions, while the Dy3+-Mn4+ interactions can sustain against the substitution until a level as high as x = 0.2. In addition, the independent Dy spin ordering is shifted remarkably down to an extremely low temperature due to the Al3+ substitution. The present work unveils the possibility of tailoring the Mn3+-Mn4+ and Dy3+-Mn4+ interactions independently, and thus reversing the ferroelectric polarization.
Evaluating the effect of orientation angles on the output power of a stationary photovoltaic panel
Authors: Asowata Osamede , Swart James , Pienaar Christo
Published: August 2014

Economic and environmental concerns over fossil fuels encourage the development of photovoltaic (PV) energy systems. The aim of this paper is to evaluate the effect of orientation angles on the output power of a PV panel, thereby harnessing more of the available solar energy. The practical setup consists of a number of identical PV systems where the PV panels were set to an orientation angle of 0° N, +15° W, and −15° E, with a constant tilt angle of 36°. Tilt and orientation angles play a major role in dictating the output power of a PV panel and subsequently on the power fed into the respective load within the PV system. Preliminary results, which include percentages showing when the system was fully charged and the work-time per day, indicate that a 0° N orientation angle produces the highest amount of output power for a latitude of 26° S.
Mode change of vortex core oscillation induced by large direct current in 120 nm sized current perpendicular-to-plane giant magnetoresistance devices with a perpendicular polarizer
Authors: Kawada Yuki , Naganuma Hiroshi , Demiray Ahmet Serdar , Oogane Mikihiko , Ando Yasuo
Published: August 2014

Current-induced microwave spectra were measured in small-sized giant magnetoresistance devices composed of a NiFe vortex free layer and an out-of-plane magnetized Co/Pd multilayer polarizer. The influence of a large direct current (DC) and a bias field on the excited mode of the free layer is systematically investigated. For small current values, microwave spectra due to the vortex core oscillation were observed around 1 GHz, while the frequency abruptly changed to 4–4.5 GHz at certain DC values. The experimental data were reproduced by micromagnetic simulation, which indicates that the mode change of the vortex core oscillation in the free layer is dominated by the Oersted field from the large DC.
Preparation of graphene oxide/epoxy nanocomposites with significantly improved mechanical properties
Authors: Galpaya D. , Wang M. , George G. , Motta N. , Waclawik E. , Yan C.
Published: August 2014

The effect of graphene oxide (GO) on the mechanical properties and the curing reaction of Diglycidyl Ether of Bisphenol A/F and Triethylenetetramine epoxy system was investigated. GO was prepared by oxidation of graphite flakes and characterized by spectroscopic and microscopic techniques. Epoxy nanocomposites were fabricated with different GO loading by solution mixing technique. It was found that incorporation of small amount of GO into the epoxy matrix significantly enhanced the mechanical properties of the epoxy. In particular, model I fracture toughness was increased by nearly 50% with the addition of 0.1 wt. % GO to epoxy. The toughening mechanism was understood by fractography analysis of the tested samples. The more irregular, coarse, and multi-plane fracture surfaces of the epoxy/GO nanocomposites were observed. This implies that the two-dimensional GO sheets effectively disturbed and deflected the crack propagation. At 0.5 wt. % GO, elastic modulus was ∼35% greater than neat epoxy. Differential scanning calorimetry (DSC) results showed that GO addition moderately affect the glass transition temperature (Tg) of epoxy. The maximum decrease of Tg by ∼7 °C was shown for the nanocomposite with 0.5 wt. % GO. DSC results further revealed that GO significantly hindered the cure reaction in the epoxy system.
Synthesis and properties of ferromagnetic nanostructures embedded within a high-quality crystalline silicon matrix via ion implantation and nanocavity assisted gettering processes
Authors: Malladi Girish , Huang Mengbing , Murray Thomas , Novak Steven , Matsubayashi Akitomo , LaBella Vincent , Bakhru Hassaram
Published: August 2014

Integrating magnetic functionalities with silicon holds the promise of developing, in the most dominant semiconductor, a paradigm-shift information technology based on the manipulation and control of electron spin and charge. Here, we demonstrate an ion implantation approach enabling the synthesis of a ferromagnetic layer within a defect free Si environment by exploiting an additional implant of hydrogen in a region deep below the metal implanted layer. Upon post-implantation annealing, nanocavities created within the H-implanted region act as trapping sites for gettering the implanted metal species, resulting in the formation of metal nanoparticles in a Si region of excellent crystal quality. This is exemplified by the synthesis of magnetic nickel nanoparticles in Si implanted with H+ (range: ∼850 nm; dose: 1.5 × 1016 cm−2) and Ni+ (range: ∼60 nm; dose: 2 × 1015 cm−2). Following annealing, the H implanted regions populated with Ni nanoparticles of size (∼10–25 nm) and density (∼1011/cm2) typical of those achievable via conventional thin film deposition and growth techniques. In particular, a maximum amount of gettered Ni atoms occurs after annealing at 900 °C, yielding strong ferromagnetism persisting even at room temperature, as well as fully recovered crystalline Si environments adjacent to these Ni nanoparticles. Furthermore, Ni nanoparticles capsulated within a high-quality crystalline Si layer exhibit a very high magnetic switching energy barrier of ∼0.86 eV, an increase by about one order of magnitude as compared to their counterparts on a Si surface or in a highly defective Si environment.
Effect of electric-field on the perpendicular magnetic anisotropy and strain properties in CoFeB/MgO magnetic tunnel junctions
Authors: Naik V. B. , Meng H. , Xiao J. X. , Liu R. S. , Kumar A. , Zeng K. Y. , Luo P. , Yap S.
Published: August 2014

In this article, we investigate the effect of electric-field on the perpendicular magnetic anisotropy (PMA) and strain properties in nanoscaled CoFeB/MgO magnetic tunnel junction using tunnel magnetoresistance and piezoresponse force microscopy (PFM) measurements, respectively. We show that while the PMA change under electric-field is consistent with the previous reports, the PFM data show that the applied electric-field induces strain in a nanoscaled MgO. We demonstrate that the development of compressive and tensile strains corresponding to different polarities of applied electric-field. We discuss the interplay between the electric-field controlled PMA and strain properties. Our results may accelerate the development of magnetoelectrically controlled spintronic devices for low-power and high-density magnetic data storage applications.
Atomistic modeling of the sputtering of silicon by electrosprayed nanodroplets
Authors: Saiz Fernan , Gamero-Castaño Manuel
Published: August 2014

The hypervelocity impact of electrosprayed nanodroplets on single-crystal silicon ejects a large number of atoms. Although sputtering by atomic, molecular, and gas cluster ions has been thoroughly studied, the significantly larger size of nanodroplets prevents a straightforward extrapolation of the physics governing the impact of these smaller projectiles. This motivates the present molecular dynamics simulations of nanodroplet impact on silicon, aimed at resolving the mechanisms and the effect of the projectile's size and velocity on sputtering. We find that both collision cascades and thermal sputtering contribute to the overall atom ejection, the former being active during the initial stages of the impact characterized by strong interactions between the molecules of the projectile and the atoms of the target, and the absence of partial thermodynamic equilibrium. In addition, for sufficiently large projectile diameters and impact velocities, conglomerates of atoms are ejected by hydrodynamic forces. The sputtering yield, defined as the average number of target atoms ejected per projectile's molecule, increases monotonically with the kinetic energy of the molecules and, at constant molecular kinetic energy, slightly decreases with projectile diameter as a result of enhanced backscattering of the ejected atoms by the projectile's molecules. For the ionic liquid considered in this study, sputtering is first observed at molecular energies near 12.7 eV and, at the highest energy simulated of 73 eV, the sputtering yield averages to 0.37.
Detection and characterization of multi-filament evolution during resistive switching
Authors: Mickel Patrick R. , Lohn Andrew J. , Marinella Matthew J.
Published: August 2014

We report resistive switching data in TaOx memristors displaying signatures of multi-filament switching modes and present a technique which enables the characterization of the evolution of multiple filaments within a single device during switching, including their temperature, heat flow, conductivity, and time evolving areas. Using a geometrically defined equivalent circuit, we resolve the individual current/voltage values of each filament and demonstrate that the switching curves of each filament collapse onto a common curve determined by the analytical steady-state resistive switching solution for filamentary switching. Finally, we discuss operational modes which may limit the formation of additional conducting filaments, potentially leading to increased device endurance.
The heating system with solar energy and heat pump in the purification of Shanxi's rural environment
Authors: Xie Guang-liang , Li Bao-chun , Chen Bao-ming
Published: August 2014

By questionnaire surveys, we analyze the statistics of heating mode, energy consumption and pollutant discharge of residential heating in 55 counties of 11 cities in Shanxi province. We estimate and discuss the energy efficiency and the emission reduction in the wide application of the heating system with solar energy and heat pump in the province. It is suggested to solve the problems in the promotion of the heating system.
In situ monitoring of structure formation in the active layer of polymer solar cells during roll-to-roll coating
Authors: Rossander Lea H. , Zawacka Natalia K. , Dam Henrik F. , Krebs Frederik C. , Andreasen Jens W.
Published: August 2014

The active layer crystallization during roll-to-roll coating of organic solar cells is studied in situ. We developed an X-ray setup where the coater unit is an integrated part of the small angle X-ray scattering instrument, making it possible to control the coating process while recording scattering measurements in situ, enabling us to follow the crystal formation during drying. By varying the distance between the coating head and the point where the X-ray beam hits the film, we obtained measurements of 4 different stages of drying. For each of those stages, the scattering from as long a foil as possible is summed together, with the distance from coating head to scattering point kept constant. The results are average crystallographic properties for the active layer coated on a 30 m long foil. With this insight into the dynamics of crystallization in a roll-coated polymer film, we find that the formation of textured and untextured crystallites seems uncorrelated, and happens at widely different rates. Untextured P3HT crystallites form later in the drying process than expected which may explain previous studies speculating that untextured crystallization depends on concentration. Textured crystallites, however, begin forming much earlier and steadily increases as the film dries, showing a development similar to other in situ studies of these materials.
Does like attract like?
Authors: Murovec T. , Brosseau C.
Published: August 2014

We present numerical simulations that allow us to compute the electrostatic force for several static configurations (i.e., metal-metal or metal-metal coated with an insulating layer) of two spherical macroscopic bodies. A key finding, relevant for potential applications in industry and future research, is that the proximity of the bodies induces in all configurations a repulsion-to-attraction (RTA) transition. It turns out that the RTA transition and the surface charge density distribution are controlled by the coating layer permittivity and the gap distance between the bodies giving credence to the interpretation that the transition mechanism is universal considered.
Graphene with adatoms: Tuning the magnetic moment with an applied voltage
Authors: Pike N. A. , Stroud D.
Published: August 2014

We show that, in graphene with a small concentration of adatoms, the total magnetic moment μT can be switched on and off by varying the Fermi energy EF, either by applying a gate voltage or by suitable chemical doping. Our calculation is carried out using a simple tight-binding model described previously, combined with a mean-field treatment of the electron-electron interaction on the adatom. The values of EF at which the moment is turned on or off are controlled by the strength of the hopping between the graphene sheet and the adatom, the on-site energy of the adatom, and the strength of the electron-electron correlation energy U. Our result is qualitatively consistent with recent experiments [R. R. Nair et al., Nat. Commun. 4, 2010 (2013)].
Reflecting on the tensions faced by a community-based multicultural health navigator service
Authors: Henderson Saras , Kendall Elizabeth
Published: August 2014

The community navigator model was developed to assist four culturally and linguistically diverse communities (Sudanese, Burmese, Pacific Islander Group, Afghani) in south-east Queensland to negotiate the Australian health system and promote health. Using participatory action research, we developed the model in partnership with community leaders and members, the local health department and two non-governmental organisations. Following implementation, we evaluated the model, with the results published elsewhere. However, our evaluation revealed that although the model was accepted by the communities and was associated with positive health outcomes, the financial, social and organisational durability of the model was problematic. Ironically, this situation was inadvertently created by critical decisions made during the development process to enhance the durability and acceptability of the model. This paper explores these critical decisions, our rationale for making those decisions and the four hidden tensions that subsequently emerged. Using a reflective case study method to guide our analysis, we provide possible resolutions to these tensions that may promote the longevity and utility of similar models in the future. What is known about the topic? The use of community navigators to assist culturally diverse communities to access health services is not new. Many benefits have been documented for communities, individuals and heath service providers following the use of such models. What is not well documented is how to maintain these models in a safe and cost-effective way within the Australian health system while respecting cultural and community practices and reducing the burden of service delivery on the navigators. What does this paper add? This paper provides a perspective on how the development of community-based service models inherently places them in a position of tension that must be resolved if they are to be long lasting. Four core tensions experienced during the development and implementation of our model in south-east Queensland are explored to develop potential resolutions. What are the implications for practice? Reducing the tensions inherent in culturally appropriate community-based service models will increase the durability of the approach. By addressing these tensions, we can create a more durable pool of community navigators that can facilitate community empowerment, self-governance of health issues and a sense of community ownership of health services.
Effects of a GnRH vaccine on the movement and activity of free-living wild boar (Sus scrofa)
Authors: Quy Roger J. , Massei Giovanna , Lambert Mark S. , Coats Julia , Miller Lowell A. , Cowan David P.
Published: August 2014

Context
Fertility control is being promoted as a non-lethal means of managing wildlife populations. We recently evaluated a single-dose injectable immunocontraceptive vaccine (GonaCon™) on captive female wild boar for effectiveness and potential side effects; reproductive output was inhibited for 4–6 years, with no obvious detrimental effects on physiology and behaviour.

Aims
We injected individual free-living wild boar individuals with the fertility-control vaccine GonaCon™ to examine its effectiveness (measured as raised levels of GnRH antibodies) and looked for potential changes in movement and activity patterns.

Methods
We trapped, fitted telemetry devices to, and released wild boar individuals living in woodland in the West Midlands region of England between 2006 and 2010. We compared data on movements and activity among 10 adult females treated with the vaccine and 11 controls treated with saline only. We measured anti-GnRH antibody titres in six recaptured boar individuals as an indicator of the effectiveness of the vaccine.

Key results
Post-treatment GnRH antibody titres varied among the boar individuals; four of five treated sows resampled between 9 and 30 weeks post-injection had antibody titres high enough to block reproduction (detectable at 1 : 32 000–1 : 64 000 dilution). At least three treated females were pregnant at the time of vaccination; there was no subsequent evidence that the vaccine interfered with pregnancy. According to the distances moved per hour over a 24-h cycle and the daily activity cycle in relation to season, there were no differences in the behaviour of treated and control females that were likely to be biologically significant. The behaviour of two treated females monitored soon after vaccination and again 12 months later also showed no major differences.

Conclusions
Free-living wild boar responded to treatment with a 1.0-mL (1000 µg) dose of an anti-GnRH vaccine and no major adverse effects on activity and movement were subsequently detected.

Implications
Our results indicated that the vaccine could be more widely evaluated in the field against overabundant or nuisance populations. Such populations are increasingly found in urban areas and parks, where culling may not be an option. We suggest that further refinement of this approach for managing wild boar populations, including development of an oral vaccine, are warranted.
Novel carotenoid cleavage dioxygenase catalyzes the first dedicated step in saffron crocin biosynthesis
Authors: Frusciante Sarah , Diretto Gianfranco , Bruno Mark , Ferrante Paola , Pietrella Marco , Prado-Cabrero Alfonso , Rubio-Moraga Angela , Beyer Peter , Gomez-Gomez Lourdes , Al-Babili Salim , Giuliano Giovanni
Published: August 2014

Significance

Saffron is a triploid, sterile species whose red stigmas constitute the most expensive spice on Earth. The color, the taste, and the aroma of the spice are owed to the crocus-specific apocarotenoid accumulation of crocetin/crocins, picrocrocin, and safranal. Through deep transcriptome analysis, we identified a novel carotenoid cleavage dioxygenase (CCD) whose expression profile parallels the production of crocetin. Using
in bacterio
, in vitro, and
in planta
functional assays, we demonstrate that CCD2 is the dioxygenase catalyzing the first dedicated step in saffron crocetin biosynthesis starting from the carotenoid zeaxanthin.
Testing for ontological errors in probabilistic forecasting models of natural systems
Authors: Marzocchi Warner , Jordan Thomas H.
Published: August 2014

Significance

Science is rooted in the concept that a model can be tested against observations and rejected when necessary. However, the problem of model testing becomes formidable when we consider the probabilistic forecasting of natural systems. We show that testability is facilitated by the definition of an experimental concept, external to the model, that identifies collections of data, observed and not yet observed, that are judged to be exchangeable and can thus be associated with well-defined frequencies. We clarify several conceptual issues regarding the testing of probabilistic forecasting models, including the ambiguity of the aleatory/epistemic dichotomy, the quantification of uncertainties as degrees of belief, the interplay between Bayesian and frequentist methods, and the scientific pathway for capturing predictability.
Environmental requirements for three sea pen species: relevance to distribution and conservation
Authors: Greathead C. , González-Irusta J. M. , Clarke J. , Boulcott P. , Blackadder L. , Weetman A. , Wright P. J.
Published: August 2014

The aim is to determine the environmental requirements, estimate the extent of suitable habitat for three sea pen species, and assess the implications for marine protected areas (MPAs). The sea pen Funiculina quadrangularis and the habitat associated with two further sea pen species, Virgularia mirabilis and Pennatula phosphorea, are of key conservation importance and are recommended for protection within MPAs. This study models their potential distributions using the MAXimum ENTropy algorithm and assesses these in relation to five possible marine protected areas (pMPAs) proposed for Scottish waters. Metrics relevant to assessing the efficacy of MPAs are also presented. Four environmental variables of prime importance for predicting the presence of all three species of sea pen were identified: mud, minimum salinity, depth, and gravel. The habitat suitability index increased with mud content. The modelled distribution of F. quadrangularis indicated a deeper distribution than V. mirabilis or P. phosphorea and was not present in sediment with gravel content above 30%. Pennatula phosphorea had the smallest area of suitable habitat, while V. mirabilis had the largest. The percentage predicted suitable area for each species that was encompassed by the five pMPAs ranged from 11% for F. quadrangularis to 15% for P. phosphorea. Some of the largest areas predicted as suitable for F. quadrangularis lay outside the pMPAs. The model results indicated differences in the environmental requirements of the three species of sea pen that can be linked to the autecology of each species. Patch sizes, calculated from a binary output of the model, were used to estimate the degree of habitat fragmentation, thereby giving a partial assessment of the adequacy criterion for these pMPAs. The results suggest that potential MPAs within the study area cover sizeable areas of potential sea pen habitat. However, further areas suitable for F. quadrangularis could be considered.
Effect of binary fraction on horizontal branch morphology under tidally enhanced stellar wind
Authors: Lei Zhenxin , Chen Xuemei , Kang Xiaoyu , Zhang Fenghui , Han Zhanwen
Published: August 2014

Tidally enhanced stellar wind may affect horizontal branch (HB) morphology in globular clusters (GCs) by enhancing the mass loss of primary star during binary evolution. Lei et al. (2013a, A&A, 549, 145; 2013b, A&A, 554, 130) studied the effect of this kind of wind on HB morphology in detail, and their results indicated that a binary is a possible second-parameter (2P) candidate in GCs. Binary fraction is a very important fact in the tidally-enhanced-stellar-wind model. In this paper, we studied the effect of binary fraction on HB morphology by removing the effects of metallicity and age. Five different binary fractions (i.e., 10%, 15%, 20%, 30%, and 50%) are adopted in our model calculations. The synthetic HB morphologies with different binary fractions are obtained at different metallicities and ages. We found that, due to the great influence of metallicity and age, the effect of binary fraction on HB morphology may be masked by these two parameters. However, when the effects of metallicity and age are removed, the tendency of HB morphologies becoming bluer with increasing binary fractions is clearly presented. Furthermore, we compared our results with the observation by Milone et al. (2012, A&A, 540, 16). Our results are consistent with the observation at metal-rich and metal-poor GCs. For the GCs with intermediate metallicity, when the effect of age on HB morphology is removed, a weak tendency of HB morphologies becoming bluer with increasing binary fractions is presented in all regions of GCs, which is consistent with our results obtained in this metallicity range.
Expression of Xylella fastidiosa RpfF in Citrus Disrupts Signaling in Xanthomonas citri subsp. citri and Thereby Its Virulence
Authors: Caserta R. , Picchi S. C. , Takita M. A. , Tomaz J. P. , Pereira W. E. L. , Machado M. A. , Ionescu M. , Lindow S. , De Souza A. A.
Published: August 2014

Xylella fastidiosa and Xanthomonas citri subsp. citri, that cause citrus variegated chlorosis (CVC) and citrus canker diseases, respectively, utilize diffusible signal factor (DSF) for quorum sensing. DSF, produced by RpfF, are similar fatty acids in both organisms, although a different set of genes is regulated by DSF in each species. Because of this similarity, Xylella fastidiosa DSF might be recognized and affect the biology of Xanthomonas citri. Therefore, transgenic Citrus sinensis and Carrizo citrange plants overexpressing the Xylella fastidiosa rpfF were inoculated with Xanthomonas citri and changes in symptoms of citrus canker were observed. X. citri biofilms formed only at wound sites on transgenic leaves and were thicker; however, bacteria were unable to break through the tissue and form pustules elsewhere. Although abundant growth of X. citri occurred at wound sites on inoculated transgenic leaves, little growth was observed on unwounded tissue. Genes in the DFS-responsive core in X. citri were downregulated in bacteria isolated from transgenic leaves. DSF-dependent expression of engA was suppressed in cells exposed to xylem sap from transgenic plants. Thus, altered symptom development appears to be due to reduced expression of virulence genes because of the presence of antagonists of DSF signaling in X. citri in rpfF-expressing plants.
Silencing Suppressor Protein VPg of a Potyvirus Interacts With the Plant Silencing-Related Protein SGS3
Authors: Rajamäki Minna-Liisa , Streng Janne , Valkonen Jari P. T.
Published: August 2014

Viral genome-linked protein (VPg) of potyviruses is involved in multiple steps of the potyvirus infection cycle, including viral multiplication and movement in plants. Recently, we showed that VPg of Potato virus A (PVA; genus Potyvirus) suppresses sense-mediated RNA silencing, which is linked to one or both nuclear or nucleolar localization. Here, we studied interactions between VPg and components of the plant RNA silencing pathway. Results showed that VPg interacts with the SGS3 protein of Solanum tuberosum and Arabidopsis thaliana, as shown by yeast two-hybrid analysis and bimolecular fluorescence complementation assays. VPg–SGS3 interactions co-localized with small cytoplasmic bodies that contained plant RNA-dependent RNA polymerase 6 (RDR6) (likely SGS3/RDR6 bodies). The N-terminal zinc finger (ZF) domain of SGS3 was the main determinant of the VPg interaction. Our data also suggest that the ZF domain controls SGS3 localization. SGS3 homodimerization was controlled by multiple protein regions. The VPg–SGS3 interaction appeared beneficial for PVA, as viral RNA levels correlated positively with sgs3 mRNA levels in the SGS3-silenced and SGS3-overexpressing leaves of Nicotiana benthamiana. The data support the idea that VPg acts as a suppressor of RNA silencing and suggest that an interaction with SGS3 may be important, especially in suppression of sense-mediated RNA silencing.
Severe Oculofacial Sequelae of Cutaneous Blastomyces dermatitidis
Authors: Schmutz Joseph S. , Ramey Nicholas A. , Gauthier Gregory M. , Lucarelli Mark J.
Published: August 2014

This study reports a case of Blastomyces dermatitidis soft tissue infection resulting in a disfiguring lower eyelid ectropion from cicatricial and postinflammatory cutaneous changes. Primary treatment included intravenous amphotericin B followed by long-term oral itraconazole, which resulted in complete remission of the disease without debridement, after which cicatricial ectropion was repaired surgically with scar release, full-thickness skin graft, and temporary Frost tarsorraphy. Cutaneous blastomycosis may cause severe oculofacial sequelae, ranging from eyelid ectropion to widespread facial cicatrix, and may mimic other more common infectious processes, in addition to malignancy. Recommended antifungal therapy includes induction with intravenous amphotericin B and a long course of oral antifungals, preferably coordinated in conjunction with an infectious disease specialist. Ectropion repair should be delayed until the inflammatory response has completely healed. If the ocular surface is compromised or nearby ocular structures are threatened, primary debridement and repair may be indicated.
Birds are islands for parasites
Authors: Koop Jennifer A. H. , DeMatteo Karen E. , Parker Patricia G. , Whiteman Noah K.
Published: August 2014

Understanding the mechanisms driving the extraordinary diversification of parasites is a major challenge in evolutionary biology. Co-speciation, one proposed mechanism that could contribute to this diversity is hypothesized to result from allopatric co-divergence of host–parasite populations. We found that island populations of the Galápagos hawk (Buteo galapagoensis) and a parasitic feather louse species (Degeeriella regalis) exhibit patterns of co-divergence across variable temporal and spatial scales. Hawks and lice showed nearly identical population genetic structure across the Galápagos Islands. Hawk population genetic structure is explained by isolation by distance among islands. Louse population structure is best explained by hawk population structure, rather than isolation by distanceper se, suggesting that lice tightly track the recent population histories of their hosts. Among hawk individuals, louse populations were also highly structured, suggesting that hosts serve as islands for parasites from an evolutionary perspective. Altogether, we found that host and parasite populations may have responded in the same manner to geographical isolation across spatial scales. Allopatric co-divergence is likely one important mechanism driving the diversification of parasites.
Field evidence for earlier leaf-out dates in alpine grassland on the eastern Tibetan Plateau from 1990 to 2006
Authors: Zhou H. K. , Yao B. Q. , Xu W. X. , Ye X. , Fu J. J. , Jin Y. X. , Zhao X. Q.
Published: August 2014

Worldwide, many plant species are experiencing an earlier onset of spring phenophases due to climate warming. Rapid recent temperature increases on the Tibetan Plateau (TP) have triggered changes in the spring phenology of the local vegetation. However, remote sensing studies of the land surface phenology have reached conflicting interpretations about green-up patterns observed on the TP since the mid-1990s. We investigated this issue using field phenological observations from 1990 to 2006, for 11 dominant plants on the TP at the levels of species, families (Gramineae—grasses and Cyperaceae—sedges) and vegetation communities (alpine meadow and alpine steppe). We found a significant trend of earlier leaf-out dates for one species (
Koeleria cristata
). The leaf-out dates of both Gramineae and Cyperaceae had advanced (the latter significantly, starting an average of 9 days later per year than the former), but the correlation between them was significant. The leaf-out dates of both vegetation communities also advanced, but the pattern was only significant in the alpine meadow. This study provides the first field evidence of advancement in spring leaf phenology on the TP and suggests that the phenology of the alpine steppe can differ from that of the alpine meadow. These findings will be useful for understanding ecosystem responses to climate change and for grassland management on the TP.
Observation of the molecular organization of calcium release sites in fast- and slow-twitch skeletal muscle with nanoscale imaging
Authors: Jayasinghe Isuru D. , Munro Michelle , Baddeley David , Launikonis Bradley S. , Soeller Christian
Published: August 2014

Localization microscopy is a fairly recently introduced super-resolution fluorescence imaging modality capable of achieving nanometre-scale resolution. We have applied the dSTORM variation of this method to image intracellular molecular assemblies in skeletal muscle fibres which are large cells that critically rely on nanoscale signalling domains, the triads. Immunofluorescence staining in fixed adult rat skeletal muscle sections revealed clear differences between fast- and slow-twitch fibres in the molecular organization of ryanodine receptors (RyRs; the primary calcium release channels) within triads. With the improved resolution offered by dSTORM, abutting arrays of RyRs in transverse view of fast fibres were observed in contrast to the fragmented distribution on slow-twitch muscle that were approximately 1.8 times shorter and consisted of approximately 1.6 times fewer receptors. To the best of our knowledge, for the first time, we have quantified the nanometre-scale spatial association between triadic proteins using multi-colour super-resolution, an analysis difficult to conduct with electron microscopy. Our findings confirm that junctophilin-1 (JPH1), which tethers the sarcoplasmic reticulum ((SR) intracellular calcium store) to the tubular (t-) system at triads, was present throughout the RyR array, whereas JPH2 was contained within much smaller nanodomains. Similar imaging of the primary SR calcium buffer, calsequestrin (CSQ), detected less overlap of the triad with CSQ in slow-twitch muscle supporting greater spatial heterogeneity in the luminal Ca
2+
buffering when compared with fast twitch muscle. Taken together, these nanoscale differences can explain the fundamentally different physiologies of fast- and slow-twitch muscle.
Towards a biomimetic gyroscope inspired by the fly's haltere using microelectromechanical systems technology
Authors: Droogendijk H. , Brookhuis R. A. , de Boer M. J. , Sanders R. G. P. , Krijnen G. J. M.
Published: August 2014

Flies use so-called halteres to sense body rotation based on Coriolis forces for supporting equilibrium reflexes. Inspired by these halteres, a biomimetic gimbal-suspended gyroscope has been developed using microelectromechanical systems (MEMS) technology. Design rules for this type of gyroscope are derived, in which the haltere-inspired MEMS gyroscope is geared towards a large measurement bandwidth and a fast response, rather than towards a high responsivity. Measurements for the biomimetic gyroscope indicate a (drive mode) resonance frequency of about 550 Hz and a damping ratio of 0.9. Further, the theoretical performance of the fly's gyroscopic system and the developed MEMS haltere-based gyroscope is assessed and the potential of this MEMS gyroscope is discussed.
Global network structure of dominance hierarchy of ant workers
Authors: Shimoji Hiroyuki , Abe Masato S. , Tsuji Kazuki , Masuda Naoki
Published: August 2014

Dominance hierarchy among animals is widespread in various species and believed to serve to regulate resource allocation within an animal group. Unlike small groups, however, detection and quantification of linear hierarchy in large groups of animals are a difficult task. Here, we analyse aggression-based dominance hierarchies formed by worker ants inDiacammasp. as large directed networks. We show that the observed dominance networks are perfect or approximate directed acyclic graphs, which are consistent with perfect linear hierarchy. The observed networks are also sparse and random but significantly different from networks generated through thinning of the perfect linear tournament (i.e. all individuals are linearly ranked and dominance relationship exists between every pair of individuals). These results pertain to global structure of the networks, which contrasts with the previous studies inspecting frequencies of different types of triads. In addition, the distribution of the out-degree (i.e. number of workers that the focal worker attacks), not in-degree (i.e. number of workers that attack the focal worker), of each observed network is right-skewed. Those having excessively large out-degrees are located near the top, but not the top, of the hierarchy. We also discuss evolutionary implications of the discovered properties of dominance networks.
Decay of (p,q)-Fourier coefficients
Authors: Edmunds David E. , Gurka Petr , Lang Jan
Published: August 2014

We show that essentially the speed of decay of the Fourier sine coefficients of a function in a Lebesgue space is comparable to that of the corresponding coefficients with respect to the basis formed by the generalized sine functions sinp,q.
A nonlinear thermodynamic model for a breakdown of the Onsager symmetry and the efficiency of thermoelectric conversion in nanowires
Authors: Cimmelli V. A. , Sellitto A. , Jou D.
Published: August 2014

We consider non-equilibrium steady-state situations for thermoelectric systems with non-local and non-linear effects. We show that the Onsager symmetry relations for effective transport coefficients break down. We also estimate the consequences of such a breakdown for the efficiency of the thermoelectric energy conversion which, under some conditions, could be higher than in the usual linear regime with Onsager symmetry.
Macroevolutionary patterns of sexual size dimorphism in copepods
Authors: Hirst Andrew G. , Kiørboe Thomas
Published: August 2014

Major theories compete to explain the macroevolutionary trends observed in sexual size dimorphism (SSD) in animals. Quantitative genetic theory suggests that the sex under historically stronger directional selection will exhibit greater interspecific variance in size, with covariation between allometric slopes (male to female size) and the strength of SSD across clades. Rensch's rule (RR) also suggests a correlation, but one in which males are always the more size variant sex. Examining free-living pelagic and parasitic Copepoda, we test these competing predictions. Females are commonly the larger sex in copepod species. Comparing clades that vary by four orders of magnitude in their degree of dimorphism, we show that isometry is widespread. As such we find no support for either RR or for covariation between allometry and SSD. Our results suggest that selection on both sexes has been equally important. We next test the prediction that variation in the degree of SSD is related to the adult sex ratio. As males become relatively less abundant, it has been hypothesized that this will lead to a reduction in both inter-male competition and male size. However, the lack of such a correlation across diverse free-living pelagic families of copepods provides no support for this hypothesis. By comparison, in sea lice of the family Caligidae, there is some qualitative support of the hypothesis, males may suffer elevated mortality when they leave the host and rove for sedentary females, and their female-biased SSD is greater than in many free-living families. However, other parasitic copepods which do not appear to have obvious differences in sex-based mate searching risks also show similar or even more extreme SSD, therefore suggesting other factors can drive the observed extremes.
Gamete evolution and sperm numbers: sperm competition versus sperm limitation
Authors: Parker Geoff A. , Lehtonen Jussi
Published: August 2014

Both gamete competition and gamete limitation can generate anisogamy from ancestral isogamy, and both sperm competition (SC) and sperm limitation (SL) can increase sperm numbers. Here, we compare the marginal benefits due to these two components at any given population level of sperm production using the risk and intensity models in sperm economics. We show quite generally for the intensity model (whereNmales compete for each set of eggs) that however severe the degree of SL, if there is at least one competitor for fertilization (N− 1 ≥ 1), the marginal gains through SC exceed those for SL, provided that the relationship between the probability of fertilization (F) and increasing sperm numbers (x) is a concave function. In the risk model, as fertilityFincreases from 0 to 1.0, the threshold SC risk (the probabilityqthat two males compete for fertilization) for SC to be the dominant force drops from 1.0 to 0. The gamete competition and gamete limitation theories for the evolution of anisogamy rely on very similar considerations: our results imply that gamete limitation could dominate only if ancestral reproduction took place in highly isolated, small spawning groups.
Representations of specific acoustic patterns in the auditory cortex and hippocampus
Authors: Kumar Sukhbinder , Bonnici Heidi M. , Teki Sundeep , Agus Trevor R. , Pressnitzer Daniel , Maguire Eleanor A. , Griffiths Timothy D.
Published: August 2014

Previous behavioural studies have shown that repeated presentation of a randomly chosen acoustic pattern leads to the unsupervised learning of some of its specific acoustic features. The objective of our study was to determine the neural substrate for the representation of freshly learnt acoustic patterns. Subjects first performed a behavioural task that resulted in the incidental learning of three different noise-like acoustic patterns. During subsequent high-resolution functional magnetic resonance imaging scanning, subjects were then exposed again to these three learnt patterns and to others that had not been learned. Multi-voxel pattern analysis was used to test if the learnt acoustic patterns could be ‘decoded’ from the patterns of activity in the auditory cortex and medial temporal lobe. We found that activity in planum temporale and the hippocampus reliably distinguished between the learnt acoustic patterns. Our results demonstrate that these structures are involved in the neural representation of specific acoustic patterns after they have been learnt.