bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of Developmental Psychobiology in the Unification of Psychology
Authors: Michel George F.
Published: June 2013

The interdisciplinary nature of Developmental Psychobiology (DPB) means that it already unifies many perspectives in psychology. DPB explanations of the development of both individual differences and species-typical behaviors include information from cells, tissue, organ systems, family, societal groups, and sociocultural customs to explain the development of both “normal” and “abnormal” behavioral traits. DPB also contextualizes understanding of the developmental processes governing the manifestation of a behavioral trait with understanding of the adaptive functions and phylogenetic history of that trait. Thus, DPB links clinical, cognitive, social, and developmental psychology with physiology, molecular biology, evolution, ecology, and developmental biology to create explanations that are relevant for education, public health, and medicine.
The Pak4 protein kinase is required for oncogenic transformation of MDA-MB-231 breast cancer cells
Authors: Wong L E , Chen N , Karantza V , Minden A
Published: June 2013

The Pak4 protein kinase, normally expressed at low level in the mammary gland, is commonly overexpressed in breast cancer. Overexpression of Pak4 transforms mouse mammary epithelial cells in vitro and renders these cells tumorigenic in athymic mice in vivo. Here we show that Pak4 is also required for oncogenic transformation of the human breast cancer cell line MDA-MB-231. These high Pak4-expressing human breast cancer cells form highly disorganized three-dimensional (3D) structures in vitro and readily give rise to orthotopic xenograft tumors in nude mice. We have found that when Pak4 levels are reduced, MDA-MB-231 cells exhibit decreased proliferation and migration in vitro, as well as gross restoration of normal 3D mammary acinar organization, the latter in association with a strong induction of apoptosis. Similarly, Pak4 knockdown suppresses MDA-MB-231 breast xenograft tumor formation in nude mice in vivo. These results indicate that Pak4 has a key role in the oncogenic transformation of breast cells.
Formaldehyde-assisted synthesis of ultrathin Rh nanosheets for applications in CO oxidation
Authors: Hou Changping , Zhu Jing , Liu Chang , Wang Xue , Kuang Qin , Zheng Lansun
Published: June 2013

Ultrathin Rh nanosheets with a thickness of approximately 1 nm were prepared via a simple solvothermal route with the assistance of formaldehyde, and they possessed good catalytic activity in CO oxidation.
Trafficking defects in PAS domain mutant Kv11.1 channels: roles of reduced domain stability and altered domain–domain interactions
Authors: Ke Ying , Ng Chai Ann , Hunter Mark J. , Mann Stefan A. , Heide Juliane , Hill Adam P. , Vandenberg Jamie I.
Published: June 2013

Loss of Kv11.1 potassium channel function is the underlying cause of pathology in long-QT syndrome type 2, one of the commonest causes of sudden cardiac death in the young. Previous studies have identified the cytosolic PAS (Per/Arnt/Sim) domain as a hotspot for mutations that cause Kv11.1 trafficking defects. To investigate the underlying basis of this observation, we have quantified the effect of mutants on domain folding as well as interactions between the PAS domain and the remainder of the channel. Apart from R56Q, all mutants impaired the thermostability of the isolated PAS domain. Six mutants, located in the vicinity of a hydrophobic patch on the PAS domain surface, also affected binding of the isolated PAS domain to an N-terminal truncated hERG (human ether-a-go-go-related gene) channel. Conversely, four other surface mutants (C64Y, T65P, A78P and I96T) and one buried mutant (L86R) did not prevent the isolated PAS domain binding to the truncated channels. Our results highlight a critical role for interactions between the PAS domain and the remainder of the channel in the hERG assembly and that mutants that affect PAS domain interactions with the remainder of the channel have a more severe trafficking defect than that caused by domain unfolding alone.
True random bit generation with time‐delay sampled‐data feedback system
Authors: Yeniçeri R. , Yalçın M.E.
Published: June 2013

A new true random bit generator circuit which is a time‐delay sampled‐data feedback system is proposed. The differential equation that defines the dynamic behaviour of the circuit is implemented by analogue active and passive components with a digital block that forms the sample and hold delay line as the feedback. A D‐type flip‐flop chain is used on the delayed feedback line due to the feedback signal which is a binary signal. The impressive features of the circuit are the ease of its implementation and the successful statistical analysis results that show its output is random. Furthermore, the reported system is the first true random bit generator using a time‐delay sampled‐data feedback system.
High‐efficiency CMOS stacked‐FET power amplifier for W‐CDMA applications using SOI technology
Authors: Jeon M.‐S. , Woo J. , Kim U. , Kwon Y.
Published: June 2013

A linear CMOS power amplifier (PA) is developed for wideband code‐division multiple‐access (W‐CDMA) application using 0.18 µm silicon‐on‐insulator (SOI) technology. By adopting a quadruple‐stacked FET structure, 1W of output power is achieved at 4V supply voltage. A negative capacitance circuit is employed to maximise the efficiency of the PA by cancelling out the excessive capacitance at the source terminal of the common‐gate stage. Besides, a lineariser based on the variable capacitor circuit is added to reduce the inherent AM‐PM distortion of the CMOS FET. Using W‐CDMA modulation at 837MHz, the fabricated PA module delivers a PAE of 47.5% and an adjacent channel leakage ratio of − 36dBc at the output power of 27.1dBm.
Multistage ADC based on integrating quantiser and gated ring oscillator
Authors: Hernández L. , Prefasi E.
Published: June 2013

Dual slope ADCs have been shown to implement noise shaping when converted into integrating quantisers, turning amplitude information into time encoded pulses. A way to increase the resolution of an integrating quantiser is to use a gated ring oscillator (GRO) to estimate the pulse length. Such combination benefits from the noise shaping effect inherent to GROs. Hence, a noise shaping order increase can be achieved by a multistage configuration when an integrating quantiser is cascaded with a GRO. The architecture and behavioural simulation of such a MASH converter is discussed. Also, the on‐line calibration of the noise cancellation filters is described.
Flexible design of decoupling and matching networks for two strongly coupled antennas
Authors: Tang X. , Mouthaan K. , Coetzee J.C.
Published: June 2013

The flexible design of decoupling and matching networks for coupled antennas is introduced. The network includes three parts: circuits for impedance transformation, an element for odd‐mode decoupling and conventional matching networks. It is found that all three parts are determined by one parameter of the ABCD matrix of the impedance transformation circuit. Thus a large variety of circuits with different element values can be used for decoupling which relaxes the practical design constraints.
Broadband coaxial holder with continuous‐conductor used for shielding effectiveness of materials against electromagnetic pulse
Authors: Chen X. , Chen Y.G. , Wei M. , Cui M.
Published: June 2013

To accurately evaluate the shielding effectiveness of materials against the electromagnetic pulse, a coaxial holder with a continuous‐conductor which uses a step transition has been developed. The particle swarm optimisation solver of CST Microwave Studio is used to design the fixed support of the coaxial holder. The cutoff frequency of the coaxial holder is up to 10 GHz with the return loss of less than − 20 dB in the frequency range of 10 MHz–8 GHz. Silver‐plated fabric and blended fabric with stainless steel fibre and polyester fibre have been tested in frequency‐domain and time‐domain, and these insertion loss and time‐domain waveforms have been compared with the 1.6GHz previous coaxial holder. Load specimens required by the broadband coaxial holder are smaller than the previous coaxial holder, while the error introduced by the broadband coaxial holder is much smaller.
Linear binary block code with prescribed minimum and maximum weight
Authors: Kohnert A.
Published: June 2013

A strategy is described which allowed new optimal binary linear codes to be constructed. Using the method, among other codes a new [48, 16, 16] optimal linear binary block code was constructed. The construction of this new code settles a conjecture mentioned in the paper by Janosov and colleagues (see appropriate Reference in Letter) where the authors found a new optimal [47, 15, 16]‐code, whose parameters are also relevant to the present author's new method.
Bias‐compensated normalised LMS algorithm with noisy input
Authors: Kang B. , Yoo J. , Park P.
Published: June 2013

A new bias‐compensated normalised least mean square (NLMS) algorithm for parameter estimation with a noisy input is proposed. The algorithm is obtained from an approximated cost function based on the statistical properties of the input noise and involves a condition checking constraint to decide whether the weight coefficient vector must be updated. Simulation results show that the proposed algorithm is more robust and accurate than the conventional method.
Dynamic backhaul resource allocation in wireless networks using artificial neural networks
Authors: Loumiotis I. , Stamatiadi T. , Adamopoulou E. , Demestichas K. , Sykas E.
Published: June 2013

The increasing bandwidth demand of end‐users renders the need for efficient resource management more compelling in next generation wireless networks. In the present work, a novel scheme incorporating the deployment of an intelligent agent capable of monitoring, storing, and predicting the forthcoming needs for resources of a base station (BS) is proposed. In this way, the BS can in advance commit the necessary resources for its backhaul connection, guaranteeing the end‐user's quality of service. The prediction process is performed using machine learning techniques.
Statistical analysis of wireless sensor network Gaussian range estimation errors
Authors: Rasool Imtiaz , Kemp Andrew H.
Published: June 2013

Wireless sensor network (WSN) localisation has attracted significant research interest. The quality of time‐of‐flight ranging when used as the basis of localisation, has a direct impact on precision and accuracy. Recently significant attention has been devoted to modelling and analysis of range estimation error (REE) in indoor and cluttered environments. A Gaussianity assumption for the distribution of REE is a common practice in the literature. The motivation of this study is to analyse this assumption. To scrutinise this, rather than relying on computer generated data, a real IEEE 802.15.4 compliant WSN test‐bed is used for collecting ranging data, covering outdoor and indoor environments for both line‐of‐sight and non‐line‐of‐sight propagation conditions. The distribution of REE is analysed using both graphical and numerical goodness‐of‐fit (GOF) techniques, that is, quantile–quantile plotting, empirical cumulative distribution function plotting, probability density function plotting, linear correlation coefficient (γ) test, kurtosis (K) test, skewness (S) test, Anderson–Darling (A2) test and chi‐squared (χ2) test. The GOF statistical analysis of the experimental results suggest that REE is not Gaussian distributed. A novel means of enhancement called the range filtration algorithm (RFA) is proposed. The RFA is based on the A2 test, it filters out the range estimates with high errors.
Context aware and channel‐based resource allocation for wireless body area networks
Authors: Rezvani Sanaz , Ghorashi Seyed Ali
Published: June 2013

Integration of miniature sensors composes a wireless body area network (WBAN), which enables remote health monitoring. To make this technology widely acceptable in the society, some studies suggest commonly used gadgets such as cell phones or laptops as a hub for WBANs. In these cases, envisaged medical and non‐medical applications of WBANs must have the same priority unless in emergency situations. Also, medical applications of WBANs need some strict requirements that are not that important for non‐medical applications, such as very low‐power consumption or reliability. In addition, channel condition may change in WBANs because of fading effects and this causes packet loss. Therefore proper traffic prioritisation, high reliability and efficient channel utilisation are vitally important issues in these networks. In this study, the authors improve the performance of the medium access control (MAC) protocol of WBANs using an adaptive resource allocation and traffic prioritisation according to the medical situation of user and channel condition. Through adaptively separating and managing the possible traffics of WBANs, the heterogeneous requirements of different applications are provided. Analytical and simulation results show that the proposed MAC protocol outperforms IEEE 802.15.4 and IEEE 802.15.6 MAC protocols in terms of power consumption as well as the channel utilisation and reliability.
Design of an ultrahigh vacuum transfer mechanism to interconnect an oxide molecular beam epitaxy growth chamber and an x-ray photoemission spectroscopy analysis system
Authors: Rutkowski M. M. , McNicholas K. M. , Zeng Zhaoquan , Brillson L. J.
Published: June 2013

We designed a mechanism and the accompanying sample holders to transfer between a VEECO 930 oxide molecular beam epitaxy (MBE) and a PHI Versa Probe X-ray photoemission spectroscopy (XPS) chamber within a multiple station growth, processing, and analysis system through ultrahigh vacuum (UHV). The mechanism consists of four parts: (1) a platen compatible with the MBE growth stage, (2) a platen compatible with the XPS analysis stage, (3) a sample coupon that is transferred between the two platens, and (4) the accompanying UHV transfer line. The mechanism offers a robust design that enables transfer back and forth between the growth chamber and the analysis chamber, and yet is flexible enough to allow transfer between standard sample holders for thin film growth and masked sample holders for making electrical contacts and Schottky junctions, all without breaking vacuum. We used this mechanism to transfer a barium strontium titanate thin film into the XPS analysis chamber and performed XPS measurements before and after exposing the sample to the air. After air exposure, a thin overlayer of carbon was found to form and a significant shift (∼1 eV) in the core level binding energies was observed.
Local hardness equalization and the principle of maximum hardness
Authors: Gázquez José L. , Vela Alberto , Chattaraj Pratim K.
Published: June 2013

The chemical potential, hardness, and hyperhardnesses equalization principles are used to show that the leading term associated with charge transfer in the total interaction energy among the fragments in which a molecule is divided is directly proportional to minus the hardness of the molecule in its ground state, as established by the principle of maximum hardness. The additional terms in the interaction energy, associated with the changes in the external potential of the fragments, provide explanation for deviations between the point of maximum hardness and the point of minimum energy. It is also found that the dual descriptor plays a very important role in hardness equalization.
A ballistic pn junction in suspended graphene with split bottom gates
Authors: Grushina Anya L. , Ki Dong-Keun , Morpurgo Alberto F.
Published: June 2013

We have developed a process to fabricate suspended graphene devices with local bottom gates, and tested it by realizing electrostatically controlled pn junctions on a suspended graphene mono-layer nearly 2 μm long. Measurements as a function of gate voltage, magnetic field, bias, and temperature exhibit characteristic Fabry-Perot oscillations in the cavities formed by the pn junction and each of the contacts, with transport occurring in ballistic regime. Our results demonstrate the possibility to achieve a high degree of control on the local electronic properties of ultra-clean suspended graphene layers, a key aspect for the realization of high quality graphene nanostructures.
In situ focus characterization by ablation technique to enable optics alignment at an XUV FEL source
Authors: Gerasimova N. , Dziarzhytski S. , Weigelt H. , Chalupský J. , Hájková V. , Vyšín L. , Juha L.
Published: June 2013

In situ focus characterization is demonstrated by working at an extreme ultraviolet (XUV) free-electron laser source using ablation technique. Design of the instrument reported here allows reaching a few micrometres resolution along with keeping the ultrahigh vacuum conditions and ensures high-contrast visibility of ablative imprints on optically transparent samples, e.g., PMMA. This enables on-line monitoring of the beam profile changes and thus makes possible in situ alignment of the XUV focusing optics. A good agreement between focal characterizations retrieved from in situ inspection of ablative imprints contours and from well-established accurate ex situ analysis with Nomarski microscope has been observed for a typical micro-focus experiment.
Dynamic evaluation of wind turbine health condition based on Gaussian mixture model and evidential reasoning
Authors: Dong Yuliang , Fang Fang , Gu Yujiong
Published: June 2013

Condition-based maintenance is an effective way to reduce operation and maintenance cost of wind turbine. Highly complex and non-stationary operational conditions of wind turbine pose a challenge to conventional condition monitoring technique. Thus, a systematic multi-parameter health condition evaluation framework that considers the dynamic operational conditions is proposed. After characteristic parameter selection and Gaussian mixture model based multi-regime modeling, evidential reasoning is developed to evaluate the health condition of wind turbine. The proposed approach shows good health condition evaluation performance not only on the parameter level but also on the component and system level. Case studies indicate the effectiveness and potential applications of the proposed method for the wind turbine health condition evaluation.
Present and prospective energy use potentials of selected agricultural wastes in Nigeria
Authors: Anyanwu C. N. , Ibeto C. N. , Eze I. S. , Ezeoha S. L.
Published: June 2013

The present study reviews the potential energy applications of wastes derived from rice, cocoa, and oil palm to augment energy needs while helping to abate environmental pollution. It also highlights the potentials of animal dungs for energy production in Nigeria. The country currently produces about 2.7 × 106 tons of rice annually, containing 0.540 × 106 tons of rice husk and a similar quantity of straw, which can be used for energy production. About 6.22 × 109 MJ of energy can be derived from the 266 000 tons (which could rise to 490 000 tons by 2015) of cocoa pods, which are currently produced and discarded annually. This could be utilized to generate process heat, either through thermal cycle or biochemical conversion. With respect to oil palm wastes, Nigeria generated about 0.344 × 106 tonnes of empty fruit bunches, 0.246 × 106 tonnes of palm shells, 0.633 × 106 tonnes of palm oil mill effluent, and 0.382 × 106 tonnes of mesocarp fibre in 2012, which are capable of producing substantial amounts of energy. Nigeria's livestock population is increasing at an annual rate of 3.2%, with current dung production of 407 × 103 tons/day (cow), 28 × 103 tons/day (pigs), 6.6 × 103 tons/day (chicken broilers), etc., which is estimated to produce 6.8 × 106 m3 of biogas daily. Electricity derivable from this quantity of biogas can provide lighting for 2.4 × 106 rural households in Nigeria.
Stabilizing gene regulatory networks through feedforward loops
Authors: Kadelka C. , Murrugarra D. , Laubenbacher R.
Published: June 2013

The global dynamics of gene regulatory networks are known to show robustness to perturbations in the form of intrinsic and extrinsic noise, as well as mutations of individual genes. One molecular mechanism underlying this robustness has been identified as the action of so-called microRNAs that operate via feedforward loops. We present results of a computational study, using the modeling framework of stochastic Boolean networks, which explores the role that such network motifs play in stabilizing global dynamics. The paper introduces a new measure for the stability of stochastic networks. The results show that certain types of feedforward loops do indeed buffer the network against stochastic effects.
Spin-wave resonance reflection and spin-wave induced domain wall displacement
Authors: Wang Xi-Guang , Guo Guang-Hua , Zhang Guang-Fu , Nie Yao-Zhuang , Xia Qing-Lin
Published: June 2013

Spin-wave propagation and spin-wave induced domain wall motion in nanostrips with a Néel wall are studied by micromagnetic simulations. It is found that the reflection of spin waves by the wall can be resonantly excited due to the interaction between spin waves and domain-wall normal modes. With the decrease of the saturation magnetization Ms (and the consequent increase of the wall width), the reflection is diminished and complete transmission can occur. The domain wall motion induced by spin waves is closely related to the spin-wave reflectivity of the wall, and may exhibit different types of behavior. The reflected spin waves (or magnons) give rise to a magnonic linear momentum-transfer torque, which drives the wall to move along the spin wave propagation direction. The maximal velocity of the domain wall motion corresponds to the resonance reflection of the spin waves. The transmitted spin waves (or magnons) lead to a magnonic spin-transfer torque, which drags the wall to move backwardly. The complicated domain wall motion can be described qualitatively by a one-dimensional model incorporating both the magnonic linear momentum-transfer torque and the magnonic spin-transfer torque. The results obtained here may find use in designing magnonic nanodevices.
Dynamics of photoexcited carriers and spins in InAsP ternary alloys
Authors: Meeker M. A. , Magill B. A. , Merritt T. R. , Bhowmick M. , McCutcheon K. , Khodaparast G. A. , Tischler J. G. , McGill S. , Choi S. G. , Palmstrøm C. J.
Published: June 2013

The recent rapid progress in the field of spintronics involves extensive measurements of carrier and spin relaxation dynamics in III-V semiconductors. In addition, as the switching rates in devices are pushed to higher frequencies, it is important to understand carrier dynamic phenomena in semiconductors on femtosecond time-scales. In this work, we employed time and spin resolved differential transmission measurements; to probe carrier and spin relaxation times in several InAsP ternary alloys. Our results demonstrate the sensitivity of the spin and carrier dynamics in this material system to the excitation wavelengths, the As concentrations, and temperature.
High order sideband generation in terahertz quantum cascade lasers
Authors: Cavalié P. , Freeman J. , Maussang K. , Strupiechonski E. , Xu G. , Colombelli R. , Li L. , Davies A. G. , Linfield E. H. , Tignon J. , Dhillon S. S.
Published: June 2013

We demonstrate the generation of high order terahertz (THz) frequency sidebands (up to 3rd order) on a near infrared (NIR) optical carrier within a THz quantum cascade laser (QCL). The NIR carrier is resonant with the interband transition of the quantum wells composing the QCL, allowing the nonlinearity to be enhanced and leading to frequency mixing. A phonon depopulation based QCL with a double metal cavity was used to enhance the intracavity power density and to demonstrate the higher order sidebands. The 1st order sideband intensity shows a linear dependence with THz power corresponding to a single THz photon, while the second order sideband has a quadratic dependence implying a two THz photon interaction and hence a third order susceptibility. These measurements are compared to the photoluminescence and the QCL bandstructure to identify the states involved, with the lowest conduction band states contributing the most to the sideband intensity. We also show that the interaction for the second order sideband corresponds to an enhanced direct third order susceptibility χ(3) of ∼7 × 10−16(m/V)2, two orders of magnitude greater than the bulk value.
Faster and highly luminescent ferroelectric liquid crystal doped with ferroelectric BaTiO3 nanoparticles
Authors: Ganguly Prasun , Kumar A. , Tripathi Shashank , Haranath D. , Biradar A. M.
Published: June 2013

The results pertaining to faster electro-optic response time and improved photoluminescence (PL) of BaTiO3 nanoparticles (BT NPs) doped ferroelectric liquid crystal (FLC) are presented. The observed increase (∼2 fold) in PL intensity and simultaneous reduction of response time have been achieved for an optimal BT NPs doping of 0.2 wt. %. These are attributed to the large dipole moment of BT that couples effectively with that of FLC molecules. These studies would provide benchmark for realization of high luminescent FLC devices that are faster in response.
X-ray microlaminography with polycapillary optics
Authors: Dąbrowski K. M. , Dul D. T. , Wróbel A. , Korecki P.
Published: June 2013

We demonstrate layer-by-layer x-ray microimaging using polycapillary optics. The depth resolution is achieved without sample or source rotation and in a way similar to classical tomography or laminography. The method takes advantage from large angular apertures of polycapillary optics and from their specific microstructure, which is treated as a coded aperture. The imaging geometry is compatible with polychromatic x-ray sources and with scanning and confocal x-ray fluorescence setups.
Characterizing the Spatiotemporal Evolution of Building-Stock Age in Poultney, Vermont: A GIS-Based Approach to Improve Thermal Efficiency in Historical Buildings
Authors: Van Hoesen John , Letendre Steven
Published: June 2013

Many industrialized countries are exploring ways to facilitate the prioritization of efforts targeting improved thermal efficiency in an aging building stock. Older buildings, typically, have inefficient building envelopes and higher energy-consumption patterns relative to new construction, which contributes to higher overall energy consumption at the local and regional scale. Reducing energy consumption by increasing the efficiency of older buildings will result in lower anthropogenic greenhouse gas emissions and help address the growing issues related to climate change. To address these concerns a GIS-based approach is developed to evaluate building-stock age in rural communities with limited access to historical parcel data. This approach involves georeferencing historical Sanborn insurance maps, digitizing building footprints for each year. This methodology is applied to a small town in rural Vermont and a map is produced depicting the spatiotemporal evolution of building construction over the years 1885–1940. 1091 structures built prior to 1941 are identified and it is argued that weatherization efforts should focus on the oldest buildings first and sequentially address younger structures, lowering both energy consumption and greenhouse gas emissions associated with the least-efficient building stock.
Recovering 3-D Shape: Roles of Absolute and Relative Disparity, Retinal Size, and Viewing Distance as Studied with Reverse-Perspective Stimuli
Authors: Dobias Joshua J , Papathomas Thomas V
Published: June 2013

When viewing reverspective stimuli, data-driven signals such as disparity, motion parallax, etc, help to recover veridical three-dimensional (3-D) shape. They compete against schema-driven influences such as experience with perspective, foreshortening, and other pictorial cues that favor the perception of an illusory depth inversion. We used three scaled-size versions of a reverspective to study the roles of retinal size, binocular disparity, and viewing distance—that influences both vergence and accommodation—in recovering the true 3-D shape. Experiment 1 used three conditions, in each of which a parameter was kept fixed across the three stimulus sizes: (a) fixed retinal size, (b) fixed viewing distance, (c) fixed disparity. The predominance of the veridical percept was recorded. Generally, the illusion strength was the same when the viewing distance was fixed, despite significantly different disparities and retinal sizes; conversely, illusion strength changed significantly in fixed-disparity and fixed-retinal-size conditions. Experiment 2 confirmed the results of experiment 1b (roughly equal performances for fixed viewing distance, independent of size) for two additional distances. Viewing distance and “scaled disparity” (disparity divided by retinal size) are good predictors of the data trends. We propose that disparity scaling is supported by both mathematical and 3-D shape considerations.
The Influence of Spatial and Feature Probability Cuing in Visual Search
Authors: Schwark Jeremy , Dolgov Igor
Published: June 2013

Certain aspects of a visual search task, such as the location where a target often appears, are learned over time and can serve as a source of attentional guidance. An example of this implicit learning, spatial probability cuing speeds detection of targets that appear in probable locations. The current study investigated target feature probability learning and its relation to implicit spatial probability learning. Results reveal that individuals are sensitive to small changes in the spatial probability of targets, even incidentally learning moderate probabilities. However, feature-based probability differences impacted visual search times much less. Implications for these findings are discussed.
Formation of Dynamic Duolayer Systems at the Air/Water Interface by using Non-ionic Hydrophilic Polymers
Authors: Prime Emma L. , Tran Diana N.H. , Leung Andy H.M , Sunartio Devi , Qiao Greg G. , Solomon David H.
Published: June 2013

The inclusion of a water-soluble polymer, poly(vinyl pyrrolidone) (PVP), into a surface active film composition before application to the water surface leads to the formation of a dynamic duolayer; a novel surface film system. This duolayer shows improved surface viscosity over the monolayer compound alone, while the addition of polymer maintains other film properties such as evaporation control and equilibrium spreading pressure. Brewster Angle Microscopy shows that the duolayer film undergoes a different formation mechanism upon film compression, and the resultant surface pressure/area isotherm is different at lower surface pressures indicating the PVP is present on the water surface at these pressures and squeezed out to the water subphase at higher pressures. The addition of water-soluble polymers to form a dynamic duolayer provides a unique way to produce defect-free and tightly packed films while polymer is associated with the film. This finding provides new knowledge for the design of surface films with improved properties with potential applications in many areas.
Applications of Mass Spectrometry in Proteomics
Authors: Sokolowska Izabela , Wetie Armand G. Ngounou , Woods Alisa G. , Darie Costel C.
Published: June 2013

Characterisation of proteins and whole proteomes can provide a foundation to our understanding of physiological and pathological states and biological diseases or disorders. Constant development of more reliable and accurate mass spectrometry (MS) instruments and techniques has allowed for better identification and quantification of the thousands of proteins involved in basic physiological processes. Therefore, MS-based proteomics has been widely applied to the analysis of biological samples and has greatly contributed to our understanding of protein functions, interactions, and dynamics, advancing our knowledge of cellular processes as well as the physiology and pathology of the human body. This review will discuss current proteomic approaches for protein identification and characterisation, including post-translational modification (PTM) analysis and quantitative proteomics as well as investigation of protein–protein interactions (PPIs).
Early increased expression of a cyclin-dependant protein kinase (LtCDKA1;1) during inflorescence initiation of the long day grass Lolium temulentum
Authors: Gocal Greg F. W. , King Rod W.
Published: June 2013

Knowing where and when different genes express at the shoot apex during the transition to flowering will help in understanding this developmental switch. The CDKA family of serine/threonine kinase genes are appropriate candidates for such developmental switching as they are involved in the regulation of the G1/S and G2/M boundaries of the cell cycle (see review by Dudits et al. 2007) and so could regulate increases of cell division associated with flowering. Furthermore, in rice stems the gibberellin (GA) class of plant growth regulators rapidly upregulate CDKA expression and cell division. Thus, CDKA expression might be linked to the florigenic action of GA as a photoperiodically-generated, signal. For the grass Lolium temulentum L., we have isolated an LtCDKA1;1 gene, which is upregulated in shoot apices collected soon after the start of a single florally inductive long day (LD). In contrast to weak expression of LtCDKA1;1 in the vegetative shoot apex, in situ and PCR-based mRNA assays and immunological studies of its protein show very rapid increases in the apical dome at the time that florigenic signals arrive at the apex (<6 h after the end of the LD). By ~54 h LtCDKA1;1 mRNA is localised to the floral target cells, the spikelet primordia. Later both LtCDKA1;1 mRNA and protein are most evident in floret meristems. Only ~10% of cells within the apical dome are dividing at any time but the LD increase in LtCDKA1;1 may reflect an early transient increase in the mitotic index (Jacqmard et al. 1993) as well as a later increase when spikelet primordia form. Increased expression of an AP1-like gene (LtMADS2) follows that of LtCDKA1;1. Overall, LtCDKA1;1 is a useful marker of both early florigenic signalling and of later morphological/developmental aspects of the floral transition.
Nonequilibrium Process in the σ Model and Chemical Relaxation Time in a Homogeneous Pionic Gas
Authors: Ishii Mitsuru
Published: June 2013

In a homogeneous pionic gas system, a chemical nonequilibrium process is
understood to have an effect in the expansion processes that are realized
immediately after heavy ion collisions. The chemical relaxation time is
calculated by incorporating the π+π↔π +π
+π+π reaction, which is given in the second order of
perturbation in the s model. The π+π↔π +π
+π+π reaction is assumed to be less frequent than the
π+π↔π +π scattering that is expected to
establish the local equilibrium, and the hydrodynamical equation is solved for
various initial conditions. It is shown that the relaxation time is of the
order of 100 fm and does not have a significant effect on the expansion
process, which implies that the pion number freezeout takes place at an early
stage of the expansion.
Nuclear Transparency in a Relativistic Quark Model
Authors: Kohama Akihisa , Iwama Tetsu , Yazak Koichi
Published: June 2013

We examine the nuclear transparency for the
(e, e′p) reaction, applying
a relativistic quark model to incorporate the internal dynamics of the struck
proton. We find that the relativistic covariance plays an important role for
so-called ‘colour transparency’.
Structure Functions of the Nucleon in a Covariant Scalar Spectator Model
Authors: Kusaka K. , Piller G. , Thomas A. W. , Williams A. G.
Published: June 2013

Nucleon structure functions, as measured in deep-inelastic lepton scattering,
are studied within a covariant scalar diquark spectator model. Regarding the
nucleon as an approximate two-body bound state of a quark and diquark, the
Bethe–Salpeter equation (BSE) for the bound state vertex function is
solved in the ladder approximation. The valence quark distribution is
discussed in terms of the solutions of the BSE.
Are there Giant Magnetic Moments in Fe-nitrides?
Authors: Cadogan J. M.
Published: June 2013

In this paper I will review the situation regarding the claims of giant
magnetic moments in Fe–N films. This work is predominantly experimental
at present but has serious implications for the theory of 3d magnetism if it
proves to be correct.
Magnetism and Superconductivity in RNi2B2C Compounds (R = Rare-earth and Y)
Authors: Cadogan J. M.
Published: June 2013

In this paper I will review the
RNi2B2C (R = rare-earth and
Y) series of compounds. These compounds exhibit a complex interplay between
superconductivity and magnetism and are unique in that the characteristic
temperatures of these effects are comparable.
Spin-lattice Relaxation Rates of Os and Other 5d Elements in Fe
Authors: Beck E. , Brewer W. D. , Funk T. , Bobek C. , Klein E.
Published: June 2013

We give final results for the nuclear spin-lattice relaxation (SLR) rates of
5d series elements as dilute impurities in iron using the method of thermal
cycling on oriented nuclei. In this report, we emphasise some aspects of the
analysis of the relaxation curves, especially for Os and Au impurities. A
comparison of the results with theory is given.
Hyperfine Magnetic Fields for Os, Ir and Pt in Iron: Pre-equilibrium Effects, Domain Rotation and the Aharoni Effect
Authors: Stuchbery A. E. , Bezakova E.
Published: June 2013

Hyperfine fields acting on subnanosecond excited states of impurity nuclei
recoil-implanted into ferromagnetic hosts are being studied. These
measurements are sensitive to effects on the picosecond time-scale that
accompany implantation as well as to phenomena of longer duration. We review
our recent work, mainly on 5d impurities implanted into iron, which has
concerned: (i) the behaviour of the transient field at low recoil velocities,
(ii) the dependence (magnitude and direction) of the hyperfine field on the
applied field, (iii) the site distribution of the implanted nuclei, and (iv)
the time the static field takes to reach equilibrium after implantation. It is
found that the static hyperfine field takes about 10 ps after implantation to
reach equilibrium. Once equilibrium is established the internal fields may be
misaligned with respect to the direction of the external field, but this is
associated with domain rotation in an incompletely saturated sample rather
than with the ‘Aharoni effect’.
Deep Convection in the Interior of Major Planets: A Review
Authors: Yano Jun-Ichi
Published: June 2013

Theories for deep convection in the interior of major planets are reviewed.
The focus is on Busse"s theory, whose problems are critically analysed.
The importance of the analogy and differences with the Earth"s mantle
convection and oceanographic convection are emphasised.
Quantum Theory of Gravitation
Authors: Green H. S.
Published: June 2013

It is possible to construct the non-euclidean geometry of space-time from the
information carried by neutral particles. Points are identified with the
quantal events in which photons or neutrinos are created and annihilated, and
represented by the relativistic density matrices of particles immediately
after creation or before annihilation. From these, matrices representing
subspaces in any number of dimensions are constructed, and the metric and
curvature tensors are derived by an elementary algebraic method; these are
similar in all respects to those of Riemannian geometry. The algebraic method
is extended to obtain solutions of Einstein’s gravitational field
equations for empty space, with a cosmological term. General relativity and
quantum theory are unified by the quantal embedding of non-euclidean
space-time, and the derivation of a generalisation, consistent with
Einstein"s equations, of the special relativistic wave equations of
particles of any spin within representations of SO(3) ⊗ SO(4; 2). There
are some novel results concerning the dependence of the scale of space-time on
properties of the particles by means of which it is observed, and the gauge
groups associated with gravitation.
The Physics of Tachyons IV. Tachyon Electrodynamics
Authors: Dawe Ross L. , Hines Kenneth C.
Published: June 2013

A new formulation of the theory of tachyons using the same two postulates as
in specialrelativity is applied to the electrodynamics of material media. A
discussion of Lagrange’s equations and Hamilton’s equations for
‘classical’ charged tachyons shows that such a formalism is a
viable approach. An essay is included on why tachyons can be considered to be
localised particles for the purpose of calculations. Tachyonic transformations
of the electromagneticfields D, P,
H and M are shown to be the same
as for bradyonic transformations. Examples discussed include the electric
dipole moment of a tachyonic current loop, constitutive equations,
polarisation in tachyonic dielectric materials and the velocity of light in
tachyonic dielectric media. This is followed by discussions of the collision
energy loss for charged tachyonsinteracting with a material medium and a
mathematical proof that tachyons cannot emit Cherenkov radiation when passing
through a bradyonic dielectric medium.
Implications of a Nonzero Cosmological Constant and Luminosity Selection Effects on Cosmological Tests
Authors: Ubachukwu A. A.
Published: June 2013

This paper examines the implications of a nonzero cosmological constant
Λ 0 on the amount of linear
size evolution and the luminosity selection effects usually required in the
interpretation of the angular diameter–redshift
(θ–z) test. This is based on three typical
cases chosen on various plausible assumptions which can be made concerning the
contribution of Λ 0 to the
density of the universe (parametrised by
?0). The results show that a
fairly strong linear size evolution will be required to interpret the
θ–z data of extended steep spectrum quasars
for all three cases, if luminosity effects are neglected. However, this
evolution is significantly steeper in a matter-dominated universe with
?M =
?0 = 1 than in both
the flat universe with ?Λ
= 0·8, ?M
= 0·2 and an open universe with
?M = 0·2,
Λ = 0.
Furthermore, when the luminosity selection effects present in the sample are
considered, a milder size evolution is obtained for the
?M = 1,
?Λ = 0 model while
little or no size evolution is found for the other two cases. There is
therefore no significant difference in our results for an open low density
universe with ?Λ =
0 and a flat universe dominated by
?Λ predicted by
inflation. The present results therefore imply that an open low density
universe with ?M =
0·2 and ?Λ
= 0 is compatible with an inflationary model of the universe with
?M = 0·2 and
?Λ = 0 · 8.
This leads to a contradiction since the universe cannot be open and spatially
closed at the same time (the existence of one should preclude the other).
New and Old Measurements of Electron Scattering in Atomic Hydrogen
Authors: Williams J. F.
Published: June 2013

A critical look is made of discrepancies and agreements between new and old
measurements and theories for elastic and n = 2
excitation of atomic hydrogen by electron impact, mainly at 16·5, 54
and 100 eV. A discussion of earlier work indicates the contributions of
Weigold and colleagues. The diffculties of observing and modelling small
scattered fluxes at backward scattering angles and of making absolute cross
section calibrations are noted. New measurements of elastic scattering at
16·5 eV confirm earlier measured angular distributions. An absolute
calibration of the differential cross section at 16·5 eV gives
agreement within one standard deviation with intermediate energy
R-matrix and multi-pseudostate close coupling values. At
16·5 eV, measurements of the separate 2s and 2p differential cross
sections and the lambda, R and I
correlation parameters again support the values from those theories.
Effect of Radial Wavevector on Collisional Drift Waves in a Toroidal Heliac
Authors: Lewandowski J. L. V. , Ellem R. M.
Published: June 2013

A 3-field model for collisional drift waves, in the ballooning representation,
for a low-pressure stellarator plasma is presented. In particular, the effect
of a finite radial mode number (≡ θk) is
studied, and the linear growth rates for the fluctuating plasma density,
electrostatic potential and electron temperature are computed numerically by
solving the 3-field model as an initial-value problem. Numerical results for a
3-field period stellarator with low global magnetic shear are then presented.
It is found that, in a system with small global magnetic shear, the case
θk = 0 yields the fastest linear growth
rate.
The 1·67 MeV Level in 9Be
Authors: Tucker SN , Treacy PB , Komarov VV
Published: June 2013

A study has been made of the 1� 67 MeV level in 9Be using 6� 0 MeV protons to populate it via the 9Be(p, p')9Be* reaotion. The speotrum of protons inelastioally soattered at a 90� laboratory angle was fitted with a line shape based on R�matrix theory. The position of the line� shape peak above the sBe + n threshold is 25 � H ke V; this value and deduoed level parameters are in disagreement with recent results from a similar fit to the 9Be(1', n)SBe reaotion.
Secondary Electron Emission from Solid Surfaces Bombarded by Medium Energy Ions
Authors: Cawthron ER
Published: June 2013

The results of Cawthron, Cotterell, and Oliphant for the emission of electrons produced by bombardment of a metal surface with various kinds of positive ions are compared with the predictions of proposed theories. It is seen that the complexity of the interaction processes occurring when a positive ion enters a surface is such that the emission process can only be described in a non-analytical manner, using a statistical treatment. The following discussion indicates that the observed results can be predicted qualitatively over a reasonable range of bombarding energies for many targets and ions by applying the theory of Parilis and Kishinevski. The energy loss cross sections, as well as the actual ionization cross sections, are shown to be important factors in determining the total emission.
80 MHz Measurements of Jupiter's Synchrotron Emission
Authors: Slee OB , Dulk GA
Published: June 2013

The spectrum of Jupiter's synchrotron emission was extended to lower frequencies by Gower (1968), who used a meridian transit interferometer to make measurements at 81�5 MHz. However, the elements of this interferometer had primary beams 1��2 � 13� to half-voltage points and the correction to the observed interferometer pattern demanded by the presence of confusing sources within the primary beams was about three times the amplitude deduced for Jupiter. Consequently, it is important that an independent check be made of the measured value of 4�5 f.u.�
Rutherford Back Scattering of Protons at Medium Energies
Authors: Cawthron ER
Published: June 2013

In the 3-20 keV energy range for light ions we are on the threshold of validity for the Lindhard-Scharff theory, but the screening is sufficiently small for the screened Coulomb scattering to be approximated by Rutherford scattering. Using the Rutherford scattering cross section, McCracken and Freeman (1969) showed that, for an incident ion of energy E0 and atomic number Z1 upon a target of atomic number Z2, where NE is the total number of back scattered ions with energy exceeding E, I(E/E0) is an integral which McCracken and Freeman plotted numerically in their paper, and the function f(z) is approximated by for Z1 << Z2 For heavy targets the screening is not negligible and the expression (1) is only qualitative. However, it does predict the observed changes in NE with E0 to considerable accuracy, for energies in the several keV range.
Lunar Occultation Observations of 24 Radio Sources
Authors: Clarke RW
Published: June 2013

Some details of the structure of 24 radio sources have been deduced from measurements of the occultation of radio sources by the Moon. The measurements were made at Parkes between July 1964 and December 1966. Most of the sources have been resolved and shown to have structure greater than 2? arc in extent. A brief description is given of the observing technique and of the method of analysis.