bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of embedded indium nanocrystals on GaAs thermoelectric properties
Authors: Warren M. V. , Canniff J. C. , Chi H. , Morag E. , Naab F. , Stoica V. A. , Clarke R. , Uher C. , Goldman R. S.
Published: July 2013

We have examined the formation of embedded In nanocrystals (NCs) and their influence on the free carrier concentration, resistivity, thermal conductivity, and Seebeck coefficient (S) of GaAs. The In nanocrystals enhance the free carrier concentration, while electron and phonon scattering at crystallite boundaries increases the resistivity and reduces the thermal conductivity. Furthermore, the room temperature Seebeck coefficient exhibits a 25% increase due to carrier trapping. Application of this approach to more heavily doped GaAs layers will likely lead to further increases in S and reductions in resistivity.
Luminescence properties of Eu-doped GaN under resonant excitation and quantitative evaluation of luminescent sites
Authors: Wakamatsu Ryuta , Lee Dong-gun , Koizumi Atsushi , Dierolf Volkmar , Fujiwara Yasufumi
Published: July 2013

We report a study on the Eu luminescence properties of Eu-doped GaN grown on a GaN substrate by organometallic vapor phase epitaxy. The site-selective excitation of Eu ions revealed the concentration of each luminescent site using the luminescence properties under resonant excitation. The quantitative evaluation of the Eu luminescent sites showed that more than 80% of Eu ions are incorporated into a high-symmetry site. However, the photoluminescence spectrum under indirect excitation is markedly different from that under resonant excitation, which indicates that the luminescent site with high symmetry exhibits low-efficiency energy transfer from the GaN host to the luminescent site.
A low-frequency noise model with carrier generation-recombination process for pentacene organic thin-film transistor
Authors: Han C. Y. , Qian L. X. , Leung C. H. , Che C. M. , Lai P. T.
Published: July 2013

By including the generation-recombination process of charge carriers in conduction channel, a model for low-frequency noise in pentacene organic thin-film transistors (OTFTs) is proposed. In this model, the slope and magnitude of power spectral density for low-frequency noise are related to the traps in the gate dielectric and accumulation layer of the OTFT for the first time. The model can well fit the measured low-frequency noise data of pentacene OTFTs with HfO2 or HfLaO gate dielectric, which validates this model, thus providing an estimate on the densities of traps in the gate dielectric and accumulation layer. It is revealed that the traps in the accumulation layer are much more than those in the gate dielectric, and so dominate the low-frequency noise of pentacene OTFTs.
Note: Multi-confocal fluorescence correlation spectroscopy in living cells using a complementary metal oxide semiconductor-single photon avalanche diode array
Authors: Kloster-Landsberg M. , Tyndall D. , Wang I. , Walker R. , Richardson J. , Henderson R. , Delon A.
Published: July 2013

Living cells are heterogeneous and rapidly changing biological samples. It is thus desirable to measure molecular concentration and dynamics in many locations at the same time. In this note, we present a multi-confocal setup capable of performing simultaneous fluorescence correlation spectroscopy measurements, by focusing the spots with a spatial light modulator and acquiring data with a monolithic 32 × 32 single-photon avalanche photodiode array. A post-processing method is proposed to correct cross-talk effects between neighboring spots. We demonstrate the applicability of our system by simultaneously measuring the diffusion of free enhanced Green Fluorescent Protein (eGFP) molecules at nine different points in living cells.
Magnetic-field-induced enhancement of crystallinity and field-effect mobilities in phthalocyanine thin films
Authors: Tabata Kenichi , Sasaki Takayuki , Yamamoto Yohei
Published: July 2013

Organic semiconductor thin films were fabricated by thermal deposition of free-base and metal phthalocyanines under a static magnetic field. A vertical magnetic field enhanced the crystallinity of the edge-on orientation of the phthalocyanine discs, whereas a horizontal magnetic field had a minimal effect on the crystallinity. The major factor for the orientation change is attributed to the diamagnetic anisotropies of π-electrons in the phthalocyanine macrocycles. Field-effect transistors of phthalocyanine films fabricated under a vertical magnetic field exhibited better hole mobilities and on-current values with smaller threshold voltages than those of phthalocyanine films fabricated without a magnetic field.
Frequency up-converted wide bandwidth piezoelectric energy harvester using mechanical impact
Authors: Halim Miah A. , Khym S. , Park J. Y.
Published: July 2013

This paper presents an impact based frequency up-converted wide bandwidth piezoelectric energy harvester in which two high frequency piezoelectric generating beams are struck at the same time by a low frequency driving beam having horizontally extended tip mass. Change of driving beam's effective stiffness during coupled vibration after impact allows the device to broaden the −3dB bandwidth to approximately 170% and to acquire more than 61% of the maximum power generation in the vicinity (from 7 to 10.5 Hz) of the −3 dB bandwidth region as well. The efficiency of electrical power transfer is increased to approximately 85%. Each generating beam produces 377 μW peak power at 14.5 Hz under 0.6 g acceleration with corresponding power density 58.8 μW cm−3.
Multi-band photoluminescence in TiO2 nanoparticles-assembled films produced by femtosecond pulsed laser deposition
Authors: Pallotti D. K. , Orabona E. , Amoruso S. , Aruta C. , Bruzzese R. , Chiarella F. , Tuzi S. , Maddalena P. , Lettieri S.
Published: July 2013

We present an analysis of the photoluminescence (PL) properties of nanostructured titania (TiO2) thin films produced by femtosecond pulsed laser deposition. Up to four PL bands are evidenced and analyzed, corresponding to radiative transitions ranging from the blue/violet to the near-infrared. The PL analysis was carried out on as-grown and post-growth annealed samples in both above-bandgap and below-bandgap excitation conditions, and allowed evidencing definite correlations between surface area, crystal phase and PL efficiency. An interpretation of the various PL components is proposed in terms of various electron and/or hole states, according to the different structural characteristics and crystal phase of the nanoparticles-assembled films. In particular, similarities between the PL activity of as-grown amorphous nanoparticles and crystalline anatase nanoparticles highlight the role of specific surface states, offering interesting insights into the possibility of exploiting amorphous TiO2 nanoparticles for PL-based applications in which surface states play an active role.
Intrinsic memristance mechanism of crystalline stoichiometric Ge2Sb2Te5
Authors: Li Y. , Zhong Y. P. , Zhang J. J. , Xu X. H. , Wang Q. , Xu L. , Sun H. J. , Miao X. S.
Published: July 2013

The bipolar memristive switching of stoichiometric crystalline Ge2Sb2Te5 (GST) thin film has been demonstrated. In contrast to the filamentary switching reported previously for a GST memristor, the intrinsic memristance is interpreted as arising from a trap-associated space-charge limited current mechanism, which is confirmed by the frequency-dependent resistance and capacitance. The contributions of charge trapping in grain defects and grain boundary defects are analyzed, and the latter ones may dominate the resistance variation. Unraveling the intrinsic memristance of GST will help us further understand the conduction mechanism of chalcogenides and promote the design of future nonvolatile memory and neuromorphic devices.
Resonator power to frequency conversion in a cryogenic sapphire oscillator
Authors: Nand Nitin R. , Parker Stephen R. , Ivanov Eugene N. , le Floch Jean-Michel , Hartnett John G. , Tobar Michael E.
Published: July 2013

We report on the measurement and characterization of power to frequency conversion in the resonant mode of a cryogenic sapphire loaded cavity resonator, which is used as the frequency discriminating element of a loop oscillator circuit. Fluctuations of power incident on the resonator lead to changes in radiation pressure and temperature in the sapphire dielectric, both of which contribute to a shift in the resonance frequency. We measure a modulation and temperature independent radiation pressure induced power to frequency sensitivity of −0.15 Hz/mW and find that this is the primary factor limiting the stability of the resonator frequency.
Tunable stiffness of electrorheological elastomers by designing mesostructures
Authors: Cao Changyong , Zhao Xuanhe
Published: July 2013

Electrorheological elastomers have broad and important applications. While existing studies mostly focus on microstructures of electrorheological elastomers, their mesoscale structures have been rarely investigated. We present a theory on the design of mesostructures of electrorheological elastomers that consist of two phases with different permittivity. We show that the deformation of elastomers can reorient their mesostructures, which consequently results in variations of their effective permittivity, leading to stiffening, softening, or instability of the elastomer. Optimal design of the mesostructures can give giant tunable stiffness. Our theoretical model is further validated by results from numerical simulations.
Material properties of Cd1−

x

Mg

x

O alloys synthesized by radio frequency sputtering
Authors: Chen Guibin , Yu K. M. , Reichertz L. A. , Walukiewicz W.
Published: July 2013

We have studied structural, electrical, and optical properties of sputter deposited ternary CdMgO alloy thin films with total Mg concentration as high as 44%. We found that only a fraction (50%–60%) of Mg is incorporated as substitutional Mg contributing to the modification of the electronic structures of the alloys. The electrical and optical results of the Cd1−xMgxO alloys are analyzed in terms of a large upward shift of the conduction band edge with increasing Mg concentration. With the increase of the intrinsic bandgap, appropriately doped Cd-rich CdMgO alloys can be potentially useful as transparent conductors for photovoltaics.
Strong perpendicular exchange bias in sputter-deposited CoPt/CoO multilayers
Authors: Wang J. , Omi T. , Sannomiya T. , Muraishi S. , Shi J. , Nakamura Y.
Published: July 2013

Strong perpendicular exchange bias was realized in sputter-deposited CoPt/CoO multilayers. The as-deposited multilayer shows strong perpendicular magnetic anisotropy (PMA) which remains up to a critical CoPt layer thickness as thick as 4 nm. After perpendicular field cooling, the multilayer with antiferromagnetic CoO and ferromagnetic CoPt interfaces exhibits large perpendicular exchange bias of 1730 Oe. Strong PMA in the CoPt/CoO multilayer is mainly attributed to the positive magnetoelastic energy due to the remarkable in-plane tensile stress originating from the local epitaxial growth. The mechanism for the exchange bias was explained in terms of the interfacial spin structure.
Three-dimensional microstructuring of yttrium aluminum garnet crystals for laser active optofluidic applications
Authors: Choudhury D. , Rodenas A. , Paterson L. , Díaz F. , Jaque D. , Kar A. K.
Published: July 2013

We demonstrate three-dimensional microstructuring in a neodymium doped yttrium aluminum garnet (Nd:YAG) crystal. Spatially well-defined hollow microstructures deeply embedded within the material are shown to result from the creation of a pre-damage state within the Nd:YAG crystal network that is validated using luminescence and Raman analyses of the structures. This opens up the potential of fabricating next-generation optofluidic devices in optical gain materials.
Electron-ion relaxation time dependent signal enhancement in ultrafast double-pulse laser-induced breakdown spectroscopy
Authors: Harilal S. S. , Diwakar P. K. , Hassanein A.
Published: July 2013

We investigated the emission properties of collinear double-pulse compared to single-pulse ultrafast laser induced breakdown spectroscopy. Our results showed that the significant signal enhancement noticed in the double pulse scheme is strongly correlated to the characteristic electron-ion relaxation time and hence to the inter-pulse delays. Spectroscopic excitation temperature analysis showed that the improvement in signal enhancement is caused by the delayed pulse efficient reheating of the pre-plume. The signal enhancement is also found to be related to the upper excitation energy of the selected lines, i.e., more enhancement noticed for lines originating from higher excitation energy levels, indicating reheating is the major mechanism behind the signal improvement.
Observation of current-driven oscillatory domain wall motion in Ni80Fe20/Co bilayer nanowire
Authors: Zhang W. , Wong P. K. J. , Yan P. , Wu J. , Morton S. A. , Wang X. R. , Hu X. F. , Xu Y. B. , Scholl A. , Young A. , Barsukov I. , Farle M. , van der Laan G.
Published: July 2013

Direct observation of current-driven oscillatory domain wall motion above the Walker breakdown by x-ray magnetic circular dichroism in photoemission electron microscopy is reported in Ni80Fe20/Co nanowire, showing micrometer-scale displacement at ∼13 MHz. We identify two key factors that enhance the oscillatory motion: (i) increase of the hard-axis magnetic anisotropy field value |H⊥| and (ii) increase of the ratio between non-adiabatic spin-transfer parameter to the Gilbert damping coefficient, β/α, which is required to be larger than 1. These findings point to an important route to tune the long-scale oscillatory domain wall motion using appropriate geometry and materials.
Thermally stimulated depolarization current analysis for the dielectric aging of Mn and V-codoped BaTiO3 multi layer ceramic capacitor
Authors: Yoon Seok-Hyun , Park Jae-Sung , Kim Sang-Hyuk , Kim Doo-Young
Published: July 2013

Dielectric aging of Mn and V-codoped BaTiO3 was investigated. The increase of V concentration had little influence on aging, whereas that of Mn increased it. Thermally stimulated depolarization current (TSDC) of low Mn concentration specimen showed one peak, whereas Mn-increased specimen showed two peaks. The first and second peak is supposed to be caused by the phase transition of the undoped core region and the defect dipole of Mn such as MnTi″-VO•• or MnTi′-VO••, respectively. High TSDC associated with the defect dipole of Mn and significant aging rate experimentally demonstrates that the dielectric aging is controlled by the defect dipole.
Thickness dependence of the resistivity tensor in epitaxial magnetite thin films
Authors: Naftalis N. , Shperber Y. , Moyer J. A. , Ahn C. H. , Klein L.
Published: July 2013

We report a systematic study of the thickness dependence of the resistivity tensor of epitaxial thin films of magnetite (Fe3O4). We find that decreasing film thickness decreases the relative magnitude of the terms related to crystal symmetry but increases their field dependence. We attribute this behavior to the presence of antiphase boundaries in thin films of magnetite and the dependence of their density on the film thickness.
Ripple formation of free graphene ribbons driven by self-attractive forces
Authors: Ru C. Q.
Published: July 2013

A simplified model is proposed to calculate reduced self-attractive energy of a free monolayer graphene sheet due to ripples. The model admits stable periodic ripple mode of a free-standing graphene ribbon in the absence of a substrate or mechanical stress, and the predicted wavelengths are in robust agreement with observed values. The predicted minimum value of tensile force for eliminating ripples is consistent with related data reported in literature. These results suggest that even the self-attractive energy alone could be strong enough to drive ripple formation. This gives an alternative explanation for ripple formation of free graphene sheets.
Energy generation from fluidized bed gasification of rice husk
Authors: Loha Chanchal , Chattopadhyay Himadri , Chatterjee Pradip K.
Published: July 2013

Though gasification of biomass in fluidized bed system is an efficient way of biomass utilization, limited experimental data on the fluidized bed biomass gasification are available in open literature. Therefore, an experimental study of biomass gasification is conducted using a laboratory scale bubbling fluidized bed gasifier. Rice husk is used as the biomass material and air-steam mixture is used as the gasifying agent. As the non-granular nature of rice husk makes it difficult to fluidize, silica sand is used as the inert bed material to help in fluidization. Parametric studies are performed to determine the effects of reactor temperature, equivalence ratio, and steam-to-biomass ratio on the product gas composition and the heating value. The results show that both hydrogen percentage and the heating value of the product gas increase with increase in gasification temperature and steam-to-biomass ratio, but they decrease with increase in equivalence ratio. The maximum heating value (4.26 MJ/Nm3) and hydrogen percentage (13.1%) are obtained at the gasification temperature of 850 °C, equivalence ratio of 0.35 and the steam-to-biomass ratio of 0.8.
Thermal performance analysis of solar clothes dryer
Authors: Jain Nikhil , Garg Vishal , Mathur Jyotirmay
Published: July 2013

Solar clothes dryer system's thermal performance analysis is presented in this paper. The system primarily consists of a single pass flat plate solar collector and a drying cabinet. Solar collector measures 1.25 m2 with 0.015 m as air gap and drying cabinet of 0.64 m3 volume and is made of plywood having thermal insulation and with clear glass on one side. Instrumentation was done to collect the solar radiation, temperature, humidity, and air flow rate for analyzing the functional and thermal performance of the system. The experiment was conducted with three different loads of same fabric type (cotton). The drying system efficiency was found between 13.24 and 17.46% depending upon the load. The energy savings of approximately 97% can be achieved using this system, if used in place of conventional electric dryer. The experimental work was carried out in Hyderabad (India): 17°21′N78°28′ E and at altitude of 576 m in the month of February and March.
Antimony mediated growth of high-density InAs quantum dots for photovoltaic cells
Authors: Tutu F. K. , Wu J. , Lam P. , Tang M. , Miyashita N. , Okada Y. , Wilson J. , Allison R. , Liu H.
Published: July 2013

We report enhanced solar cell performance using high-density InAs quantum dots. The high-density quantum dot was grown by antimony mediated molecular beam epitaxy. In-plane quantum dot density over 1 × 1011 cm−2 was achieved by applying a few monolayers of antimony on the GaAs surface prior to quantum dot growth. The formation of defective large clusters was reduced by optimization of the growth temperature and InAs coverage. Comparing with a standard quantum dot solar cell without the incorporation of antimony, the high-density quantum dot solar cell demonstrates a distinct improvement in short-circuit current from 7.4 mA/cm2 to 8.3 mA/cm2.
Enhanced resonant transmission of electromagnetic radiation through a pair of subwavelength slits
Authors: Young S. M. , Pfeiffer C. , Grbic A. , Merlin R.
Published: July 2013

We show that a pair of subwavelength slits in parallel conducting plates supports a localized electromagnetic mode bound to the slits, whose spatial extent is determined not by the plates' size but by the slit dimensions. This mode occurs for electric fields parallel to the slits and plate separation slightly smaller than half the free-space wavelength. Finite element calculations and experimental results at 10 GHz show that the localized mode gives rise to a strong, narrowband resonant enhancement of the transmission which, while limited by conduction losses in the plates, is a factor of 104 larger than for off-resonant transmission.
A Copper Cyanide Complex with Efficient Red Luminescence
Authors: Liu Xi , Yang Yun-Zhi , Wang Chun-Hai , Huang Kun-Lin
Published: July 2013

Gaseous diffusion of diethyl ether into the solvothermal reaction mixture of copper cyanide (CuCN) with 2,2′-bipyridine (bipy) in anhydrous acetonitrile leads to a copper cyanide complex Cu(CN)(bipy) (1) with a special helical chain structure. Solid-state luminescence experiments show that complex 1 can emit efficient red luminescence, and its possible emission mechanism was investigated in detail based on theoretical calculations. The results may be helpful for the design and synthesis of more efficient luminescent materials.
Grassland dynamics in response to climate change and human activities in Inner Mongolia, China between 1985 and 2009
Authors: Mu S. J. , Chen Y. Z. , Li J. L. , Ju W. M. , Odeh I. O. A. , Zou X. L.
Published: July 2013

China’s grassland has been undergoing rapid changes in the recent past owing to increased climate variability and a shift in grassland management strategy driven by a series of ecological restoration projects. This study investigated the spatio-temporal dynamics of Inner Mongolia grassland, the main grassland region in China and part of the Eurasia Steppe, to detect the interactive nature of climate, ecosystems and society. Land-use and landscape patterns for the period from 1985 to 2009 were analysed based on TM- and MODIS-derived land-use data. Net Primary Productivity (NPP) estimated by using the Carnegie-Ames-Stanford Approach model was used to assess the growth status of grassland. Furthermore, the factors related to the dynamics of grassland were analysed from the perspectives of two driving factors, climate change and human activities. The results indicated that higher temperatures and lower precipitation may generally have contributed to grassland desertification, particularly in arid regions. During the period from 1985 to 2000, a higher human population and an increase in livestock numbers were the major driving forces responsible for the consistent decrease in NPP and a relatively fragmented landscape. From 2000 to 2009, the implementation of effective ecological restoration projects has arrested the grassland deterioration in some ecologically fragile regions. However, a rapid growth of livestock numbers has sparked new degradation onnon-degraded or lightly degraded grassland, which was initially neglected by these projects. In spite of some achievement in grassland restoration, China should take further steps to develop sustainable management practices for climate adaptation and economic development to bring lasting benefits.
Stream-bed and flood-plain rehabilitation at Mulloon Creek, Australia: a financial and economic perspective
Authors: Dobes Leo , Weber Nathan , Bennett Jeff , Ogilvy Sue
Published: July 2013

Prior to European settlement, many Australian rivers were characterised by interconnected ‘chains of ponds’, with riparian vegetation preventing scour and subsequent channel erosion. Damage and destruction of vegetation by grazing animals has resulted in stream-channel incision and associated lowering of watertables on adjacent flood-plains. Proponents of natural sequence farming seek to restore hydro-geomorphic functionality by raising stream levels through construction of leaky weirs and revegetation. Lack of documentation of ‘before and after’ production data precludes evaluation of either the financial viability or the broader economic merits of raising stream levels. A case study, based on financial and economic costs, and possible benefits, at one site, highlighted the need for more targeted research that can be combined with an economic evaluation of stream rehabilitation. Only a more focussed, multidisciplinary research effort can reveal whether it is likely to be financially viable for individual properties or to be socially beneficial. The study also identified that government agencies should commission, and publish, the results of assessments of alternative schemes that have been used to control erosion or to rehabilitate streams, for comparative purposes. Similarly, a comprehensive cost–benefit analysis should be undertaken to ensure an objective basis for regulatory control over the management of water resources on Australian properties.
Robot feedback shapes the tutor’s presentation
Authors: Pitsch Karola , Vollmer Anna-Lisa , Mühlig Manuel
Published: July 2013

The paper investigates the effects of a humanoid robot’s online feedback during a tutoring situation in which a human demonstrates how to make a frog jump across a table. Motivated by micro-analytic studies of adult-child-interaction, we investigated whether tutors react to a robot’s gaze strategies while they are presenting an action. And if so, how they would adapt to them. Analysis reveals that tutors adjust typical “motionese” parameters (pauses, speed, and height of motion). We argue that a robot – when using adequate online feedback strategies – has at its disposal an important resource with which it could proactively shape the tutor’s presentation and help generate the input from which it would benefit most. These results advance our understanding of robotic “Social Learning” in that they suggest a paradigm shift towards considering human and robot as one interational learning system. Keywords: human-robot-interaction; feedback; adaptation; multimodality; gaze; conversation analysis; social learning; pro-active robot conduct
Where the action is
Authors: Dickerson Paul , Robins Ben , Dautenhahn Kerstin
Published: July 2013

This paper examines interaction involving a child with an Autistic Spectrum Disorder, a humanoid robot and a co-present adult. In this paper data from one child (collected as part of the ROBOSKIN project) is analysed in order to evaluate the potential contributions of a conversation analytic perspective to the examination of data relating to socio-emotional reciprocity. The paper argues for the value of treating all interaction as potentially relevant, looking without carefully pre-defined target behaviours and examining behaviour within its specific sequence of interaction. Adopting this approach, the paper suggests, enables noticings and observations that might not be available from perspectives that rely on the coding of pre-specified behaviours in isolation. Treating all interaction as potentially relevant brought into view interactions that might otherwise be dismissed or ignored – because they occurred before, or after, the trial itself. Being informed by the value of unmotivated looking – rather than pre-specified coding schemes – enabled highly relevant behaviour that was not anticipated within the trials to be analysed. Finally, seeing sequence as important meant that behaviours were appreciated in their intricate detail, enabling a more precise understanding than might be available if they were considered separately from that sequential environment. Keywords: autism; assessment; autistic spectrum disorder; experiment; conversation analysis; interaction; humanoid robot; sequences; sequence of interaction; socio-emotional reciprocity
Classy Kids and Down-at-Heel Intellectuals: Status Aspiration and Blind Spots in the Contemporary Ethnography of Iran
Authors: Olszewska Zuzanna
Published: July 2013

This article reviews the ways in which class, status, social mobility and their cultural ramifications have been considered (or failed to be considered) in recent ethnographic studies of the Islamic Republic of Iran. It argues against the trend of privileging “resistance” to an oppressive state as a theoretical frame for documenting social phenomena in Iran: lifestyles and consumption patterns cannot be interpreted merely as signs of political rebellion because they are endowed with symbolic value as status attributes in a society whose class configurations are shifting. I present a number of sources and concepts that help to rethink these phenomena, and show how the experience of Afghan refugees living on the margins of Iranian cities illuminates both the opportunities and constraints created by the Islamic Republic's uneasy mix of political Islam, populism and neoliberalism. A focus on aspiration to upward mobility becomes a useful analytical lens that allows us to sidestep reductive dichotomies such as tradition/modernity or religion/secularism that are in practice blurred by its very pursuit.
Precision Analysis of Three Aging Structures for Amphidromous Dolly Varden from Alaskan Arctic Rivers
Authors: Stolarski Jason T. , Sutton Trent M.
Published: July 2013

The accuracy of population statistics and the validity of management actions they motivate are in part dependent on the acquisition of quality age determinations. Such data for northern-form Dolly Varden Salvelinus malma have been traditionally garnered using otoliths, despite little research investigating the consistency of this or alternative nonlethal techniques. To address these gaps, the precision of age determinations generated from scales, otoliths, and fin rays was examined for 126 amphidromous Dolly Varden collected from two Arctic rivers. Three independent readers, age-bias plots, coefficients of variation (CVs), and percent agreement (PA) were used to estimate bias and precision for among-reader, within-structure comparisons and within-reader, among-structure comparisons. Among-reader, within-structure tests of CVs suggested that otoliths produced more precise age determinations than fin rays. Furthermore, the CV for scales was intermediate to and not significantly different from those for otoliths and fin rays. Age-bias plots suggested that, scales consistently underestimated age relative to otolithsbeginning at age 6. Underestimation was also apparent, but less distinct, within fin ray–otolith and scale–fin ray comparisons. Potential sources of error and management implications are discussed. Because scale and otolith ages exhibited little bias within cohorts younger than age 6, age may be determined nonlethally in these cohorts using scales; otoliths should be used otherwise.

Received April 27, 2012; accepted May 13, 2013
Inhibition of Cdc42 during mitotic exit is required for cytokinesis
Authors: Atkins Benjamin D. , Yoshida Satoshi , Saito Koji , Wu Chi-Fang , Lew Daniel J. , Pellman David
Published: July 2013

The role of Cdc42 and its regulation during cytokinesis is not well understood. Using biochemical and imaging approaches in budding yeast, we demonstrate that Cdc42 activation peaks during the G1/S transition and during anaphase but drops during mitotic exit and cytokinesis. Cdc5/Polo kinase is an important upstream cell cycle regulator that suppresses Cdc42 activity. Failure to down-regulate Cdc42 during mitotic exit impairs the normal localization of key cytokinesis regulators—Iqg1 and Inn1—at the division site, and results in an abnormal septum. The effects of Cdc42 hyperactivation are largely mediated by the Cdc42 effector p21-activated kinase Ste20. Inhibition of Cdc42 and related Rho guanosine triphosphatases may be a general feature of cytokinesis in eukaryotes.
Distinct roles of Rho1, Cdc42, and Cyk3 in septum formation and abscission during yeast cytokinesis
Authors: Onishi Masayuki , Ko Nolan , Nishihama Ryuichi , Pringle John R.
Published: July 2013

In yeast and animal cytokinesis, the small guanosine triphosphatase (GTPase) Rho1/RhoA has an established role in formation of the contractile actomyosin ring, but its role, if any, during cleavage-furrow ingression and abscission is poorly understood. Through genetic screens in yeast, we found that either activation of Rho1 or inactivation of another small GTPase, Cdc42, promoted secondary septum (SS) formation, which appeared to be responsible for abscission. Consistent with this hypothesis, a dominant-negative Rho1 inhibited SS formation but not cleavage-furrow ingression or the concomitant actomyosin ring constriction. Moreover, Rho1 is temporarily inactivated during cleavage-furrow ingression; this inactivation requires the protein Cyk3, which binds Rho1-guanosine diphosphate via its catalytically inactive transglutaminase-like domain. Thus, unlike the active transglutaminases that activate RhoA, the multidomain protein Cyk3 appears to inhibit activation of Rho1 (and thus SS formation), while simultaneously promoting cleavage-furrow ingression through primary septum formation. This work suggests a general role for the catalytically inactive transglutaminases of fungi and animals, some of which have previously been implicated in cytokinesis.
Timing it right: Precise ON/OFF switches for Rho1 and Cdc42 GTPases in cytokinesis
Authors: Balasubramanian Mohan K. , Tao Evelyn Yaqiong
Published: July 2013

In many eukaryotes, cytokinesis requires an actomyosin contractile ring that is crucial for cell constriction and new membrane organization. Two studies in this issue (Onishi et al. 2013. J. Cell Biol. http://dx.doi.org.10.1083/jcb.201302001 and Atkins et al. 2013. J. Cell Biol. http://dx.doi.org.10.1083/jcb.201301090) establish that precise activation and/or inactivation of Rho1 and Cdc42 GTPases is important for the correct order and successful completion of events downstream of actomyosin ring constriction in budding yeast.
Suzanne Eaton: The beautiful logic of development
Authors: Sedwick Caitlin
Published: July 2013

Eaton studies tissue patterning in flies and mammals.
The effectiveness of using CPUE data derived from Vessel Monitoring Systems and fisheries logbooks to estimate scallop biomass
Authors: Murray Lee G. , Hinz Hilmar , Hold Natalie , Kaiser Michel J.
Published: July 2013

Murray, L. G., Hinz, H., Hold, N., and Kaiser, M. J. 2013. The effectiveness of using CPUE data derived from Vessel Monitoring Systems and fisheries logbooks to estimate scallop biomass. – ICES Journal of Marine Science, 70: . Obtaining accurate data on abundance is vital to undertaking viable stock assessments of commercially exploited species. Satellite Vessel Monitoring Systems (VMSs) combined with fisheries logbooks have the potential to provide an abundant source of data with greater spatial and temporal coverage than research surveys. However, to date it has not been demonstrated how well VMS-derived abundance or biomass indices reflect research survey results. In this study we compared biomass indices of scallops derived from (i) fishing vessel surveys, (ii) research vessel surveys, and (iii) fishery-dependent data using VMSs and logbooks. In most cases there were strong relationships between biomass indices of Pecten maximus from fishing vessels and the research vessel. There were stronger relationships between P. maximus biomass indices from fishery-dependent VMS and logbook data and research vessel data at the beginning of the fishing season, when abundance was higher, but weaker relationships at the end of the fishing season. The time and location of sampling affected biomass estimates over short periods, and without standardizing to location and vessel, biomass depletion was masked. Fishery-dependent data provides a valid means of assessing relative scallop abundance and may prove equally viable in other fisheries with appropriate standardization of Catch Per Unit Effort (CPUE) data, making real-time management of fisheries increasingly feasible.
Forage fish quality: seasonal lipid dynamics of herring (Clupea harengus L.) and sprat (Sprattus sprattus L.) in the Baltic Sea
Authors: Røjbek Maria C. , Tomkiewicz Jonna , Jacobsen Charlotte , Støttrup Josianne G.
Published: July 2013

Røjbek, M. C., Tomkiewicz, J., Jacobsen, C., and Støttrup, J. G. Forage fish quality: seasonal lipid dynamics of herring (Clupea harengus L.) and sprat (Sprattus sprattus L.) in the Baltic Sea. – ICES Journal of Marine Science, 71: . This study investigates lipid content and fatty acid composition of two important forage fish, sprat (Sprattus sprattus) and herring (Clupea harengus) in the Baltic Sea ecosystem. Seasonal variation in lipids was studied during three periods following the annual reproductive cycle considering potential differences relating to fish size, sex, and reproductive status. The isopod Saduria entomon, being at times an important prey for predatory fish, was included for comparison. In both sprat and herring, lipid content and absolute contents of essential polyunsaturated fatty acids (PUFAs) varied seasonally with high levels towards the end of the annual zooplankton production cycle, succeeded by a decline. Lipid content and fatty acid composition differed significantly between sprat and herring. Sprat lipid content was higher than herring, increasing with fish size and characterized by large proportions of monounsaturated fatty acids. Herring lipid content was related to the reproductive cycle and proportions of PUFAs were high compared with sprat. Levels of essential PUFAs were high in S. entomon compared with clupeids rendering it a valuable alternative prey species in the Baltic Sea ecosystem. The lipid dynamics of forage fish and benthos, combined with changes in availability and abundance, will affect growth and reproduction of their predators.
Loss of Starch Granule Initiation Has a Deleterious Effect on the Growth of Arabidopsis Plants Due to an Accumulation of ADP-Glucose
Authors: Ragel Paula , Streb Sebastian , Feil Regina , Sahrawy Mariam , Annunziata Maria Grazia , Lunn John E. , Zeeman Samuel , Mérida Ángel
Published: July 2013

STARCH SYNTHASE4 (SS4) is required for proper starch granule initiation in Arabidopsis (Arabidopsis thaliana), although SS3 can partially replace its function. Unlike other starch-deficient mutants, ss4 and ss3/ss4 mutants grow poorly even under long-day conditions. They have less chlorophyll and carotenoids than the wild type and lower maximal rates of photosynthesis. There is evidence of photooxidative damage of the photosynthetic apparatus in the mutants from chlorophyll a fluorescence parameters and their high levels of malondialdehyde. Metabolite profiling revealed that ss3/ss4 accumulates over 170 times more ADP-glucose (Glc) than wild-type plants. Restricting ADP-Glc synthesis, by introducing mutations in the plastidial phosphoglucomutase (pgm1) or the small subunit of ADP-Glc pyrophosphorylase (aps1), largely restored photosynthetic capacity and growth in pgm1/ss3/ss4 and aps1/ss3/ss4 triple mutants. It is proposed that the accumulation of ADP-Glc in the ss3/ss4 mutant sequesters a large part of the plastidial pools of adenine nucleotides, which limits photophosphorylation, leading to photooxidative stress, causing the chlorotic and stunted growth phenotypes of the plants.
The developmental plasticity and functional significance of an additional sperm storage compartment in female yellow dung flies
Authors: Schäfer Martin A. , Berger David , Jochmann Ralf , Blanckenhorn Wolf U. , Bussière Luc F.
Published: July 2013

The mechanistic basis for and adaptive significance of variation in female sperm storage organs are important for a range of questions concerning sexual selection and speciation, as such variation influences the evolutionary trajectories of male fertilization related traits and may facilitate speciation through its effects on gamete recognition.

Female yellow dung flies (Scathophaga stercoraria)usually develop three sperm storage compartments, and this subdivision may be an adaptation for sorting sperm during postcopulatory choice.

Using lines artificially selected to express four spermathecae (4s), we explored the fitness consequences of the novel phenotype relative to the naturally prevalent three‐spermatheca (3s) phenotype by manipulating the opportunity for postcopulatory sexual selection (females mated either with three or only one male prior to oviposition). In addition, we examined the developmental plasticity of spermathecal number in response to different larval food environments and estimated its genetic correlation with growth rate.

Mating treatments with and without the opportunity for postcopulatory sexual selection revealed no significant fitness differences between alternative spermathecal phenotypes within selection lines despite overall benefits associated with multiple mating, and moderate egg‐to‐adult survival costs in response to artificial selection for 4s. Manipulations of the larval food environment revealed that the expression of 4s is highly plastic and tightly linked to environmental conditions promoting fast somatic growth and development. Likewise, siblings with fast intrinsic (genetic) growth were more likely to express 4s within and across food environments.

The present results highlight a great potential for rapid evolutionary change in female sperm storage morphology through indirect selection on life‐history traits, and further suggest genetic assimilation as a potential mechanism facilitating phylogenetic transitions in spermatheca number as frequently observed within the Dipterans.
Climate‐driven change in plant–insect interactions along elevation gradients
Authors: Rasmann Sergio , Pellissier Loïc , Defossez Emmanuel , Jactel Hervé , Kunstler Georges
Published: July 2013

Global warming is predicted to dramatically alter communities' composition through differential colonization abilities, such as between sessile plants and their mobile herbivores. Novel interactions between previously non‐overlapping species may, however, also be mediated by altered plants' responses to herbivore attack.

Syndromes of plant defences and tolerance are driven by inherited functional traits, biotic and abiotic conditions, and the geographical and historical contingencies affecting the community. Therefore, understanding climate change‐driven herbivore responses and evolution towards a particular plant defence syndrome is key to forecasting species interactions in the near future.

In this paper, we first document variations in herbivory, and plant defences along altitudinal gradients that act as ‘natural experiments’. We then use an empirical model to predict how specialist herbivore abundance may shift with respect to elevation in the near future.

Our field surveys and field experiment showed a decrease in herbivory with elevation. However, contrary to expectations, our meta‐regression analyses showed that plant defences, particularly leaf toughness and flavonoid compounds, tend to be higher at high elevations, while secondary metabolites showed no clear trend with elevation.

Based on those results, we discuss how plant communities and species‐specific plant defence syndromes will change in response to the climate‐driven herbivore colonization of higher altitudes. Particularly, plant from high elevation, due to high protection against abiotic stress may be already ecologically fitted to resist the sudden increase in herbivory pressure that they will likely experience during global change.
Attitudes of secondary school teachers towards inclusive education in New Delhi, India
Authors: Bhatnagar Nisha , Das Ajay
Published: July 2013

This study was undertaken to determine the attitudes of secondary regular schoolteachers towards the inclusion of students with disabilities in New Delhi. A total of 470 teachers, working in schools managed by a private organisation in Delhi, returned the completed survey. A two‐part questionnaire was used in this study. Part one gathered information relating to personal and professional characteristics of the teachers. Part two was a 16‐item Likert scale titled, Attitudes towards Inclusive Education Scale. The major finding of the study was that the teachers in Delhi had positive attitudes towards the inclusion of students with special needs. This study also indicated that the teachers who were more positive about inclusive education were male, younger teachers (less than 40 years of age), less experienced (less than 10 years) and had postgraduate qualifications. In addition, the teachers who had a contact with a person with a disability and those who did not have a focus on disability during their preservice teacher education programmes were more positive towards inclusive education.
The social bases of nuclear energy policies in Europe: Ideology, proximity, belief updating and attitudes to risk
Authors: Franchino Fabio
Published: July 2013

This article analyses the social bases underpinning the widely different trajectories of nuclear energy policies across Western European countries. Employing a set of surveys carried out in the last thirty years, it examines the conditional effects of ideology and geographical proximity to a nuclear power plant on attitudes toward nuclear energy, as well as the long‐ and short‐term dynamics of belief updating after the occurrence of major accidents. Results highlight how proximity can strengthen, weaken or have no effect on the ideological component of these attitudes. Moreover, the publics of most countries with experience in nuclear energy display the traits of Bayesian dynamics of belief updating, especially in the vicinity of a plant. The article also shows the fairly exceptional traits of French public opinion. In conclusion, the broad social constraints within which governments operate, across time and space, shed light on the different policy trajectories of European countries.
The Influence of Biodiversity Provision on the Cost Structure of Swedish Dairy Farming
Authors: Gullstrand Joakim , De Blander Rembert , Waldo Staffan
Published: July 2013

Multi‐functionality and the provision of eco‐system services are politically highly prioritised aspects of farming. This study uses a Symmetric Generalised McFadden cost function to analyze the relationship between costs of production and the provision of biodiversity for Swedish milk farms. Biodiversity indicators are based on the number of valuable plant species present at the farm and are modeled as an output in the cost function. The results show that the marginal cost of biodiversity increases with higher provision, and that an increased provision of biodiversity also increases the costs of market commodities such as milk and beef. The upward slope of the marginal cost of biodiversity and its competitive relationship with market goods questions the efficiency of support schemes based on voluntary programmes with a flat‐rate per hectare compensation. Instead, the results support targeted environmental policy schemes with zonings and/or the use of biodiversity indicators.
Introduction of an accelerated diagnostic protocol in the assessment of emergency department patients with possible acute coronary syndrome: The Nambour Short Low‐Intermediate Chest pain project
Authors: George Terry , Ashover Sarah , Cullen Louise , Larsen Peter , Gibson Jason , Bilesky Jennifer , Coverdale Steven , Parsonage William
Published: July 2013

Emergency physicians can feel pressured by opposing forces of clinical reality and the need to publish successful key performance indicators in an environment of increasing demands and cost containment. This is particularly relevant to management of patients with undifferentiated chest pain and possible acute coronary syndrome. Unreliability of clinical assessment and high risk of adverse outcomes for all concerned exist, yet national guidelines are at odds with efforts to reduce ED crowding and access block. We report findings from the Nambour Short Low‐Intermediate Chest pain risk trial, which safely introduced an accelerated diagnostic protocol with reduced ED length of stay and high patient acceptability. Over a 7‐month period, there were no major adverse cardiac events by 30 days in 19% of undifferentiated chest pain presentations with possible acute coronary syndrome discharged after normal sensitive cardiac troponin taken 2 h after presentation and scheduled to return for outpatient exercise stress test.