bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Cumulative Sum Quality Control Scheme for Monitoring the Process Mean
Authors: Haq Abdul , Brown Jennifer , Moltchanova Elena
Published: June 2013

A control chart is a powerful statistical process monitoring tool that is frequently used in many industrial and service organizations to monitor in‐control and out‐of‐control performances of the manufacturing processes. Cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) control charts have been recognized as potentially powerful tool in quality and management control. These control charts are sensitive to both small and moderate changes in the process. In this paper, we propose a new CUSUM (NCUSUM) quality control scheme for efficiently monitoring the process mean. It is shown that the classical CUSUM control chart is a special case of the proposed controlling scheme. The NCUSUM control chart is compared with some of the recently proposed control charts by using characteristics of the distribution of run length, i.e. average run length, median run length and standard deviation of run length. It is worth mentioning that the NCUSUM control chart detects the random shifts in the process mean substantially quicker than the classical CUSUM, fast initial response‐based CUSUM, adaptive CUSUM with EWMA‐based shift, adaptive EWMA and Shewhart–CUSUM control charts. An illustrative example is given to exemplify the implementation of the proposed quality control scheme. Copyright © 2013 John Wiley & Sons, Ltd.
Evaluation of optical activities by modern semi‐empirical methods
Authors: Hatanaka Masashi
Published: June 2013

Modern semi‐empirical molecular orbital methods are applied herein to the direct calculation of the optical rotatory strengths of model molecules. In addition to MNDO, AM1, and PM3 methods, RM1, PM6, and PM7 wavefunctions are used for evaluation of the dipole transition moments. The octant rule for carbonyl compounds is well‐adhered to using the RM1, PM6, and PM7 methods and is reasonably consistent with the charge‐transfer perturbations with regard to the substituents. By using the up‐to‐date methods RM1 and PM7, circular dichroism (CD) spectra of a typical helicene are also well‐reproduced using complete active space configuration interactions. The CD spectral profiles are significantly improved relative to those obtained using conventional CNDO/S or INDO/S levels of theory and are complemented by optical rotatory dispersion spectra. As a platform for analyzing biopolymers, test calculations for polypeptides are also presented. © 2013 Wiley Periodicals, Inc.
Sampling strategy and analysis of trace element concentrations by inductively coupled plasma mass spectrometry on medieval human bones – the concept of chemical life history
Authors: Skytte Lilian , Rasmussen Kaare Lund
Published: June 2013

RATIONALE

Medieval human bones have the potential to reveal diet, mobility and treatment of diseases in the past. During the last two decades trace element chemistry has been used extensively in archaeometric investigations revealing such data. Many studies have reported the trace element inventory in only one sample from each skeleton – usually from the femur or a tooth. It cannot a priori be assumed that all bones or teeth in a skeleton will have the same trace element concentrations.

METHODS

Six different bone and teeth samples from each individual were carefully decontaminated by mechanical means. Following dissolution of ca. 20 mg sample in nitric acid and hydrogen peroxide the assays were performed using inductively coupled plasma mass spectrometry (ICPMS) with quadropole detection. We describe the precise sampling technique as well as the analytical methods and parameters used for the ICPMS analysis.

RESULTS

The places of sampling in the human skeleton did exhibit varying trace element concentrations. Although the samples are contaminated by Fe, Mn and Al from the surrounding soil where the bones have been residing for more than 500 years, other trace elements are intact within the bones. It is shown that the elemental ratios Sr/Ca and Ba/Ca can be used as indicators of provenance.

CONCLUSIONS

The differences in trace element concentrations can be interpreted as indications of varying diet and provenance as a function of time in the life of the individual – a concept which can be termed chemical life history. A few examples of the results of such analyses are shown, which contains information about provenance and diagenesis. Copyright © 2013 John Wiley & Sons, Ltd.
On linear instability of solitary waves for the nonlinear Dirac equation
Authors: Guan Meijiao , Comech Andrew , Gustafson Stephen
Published: June 2013

We consider the nonlinear Dirac equation, also known as the Soler model:

i\partial _{t}\psi = −i\boldsymbol{\alpha } \cdot \mathbf{∇}\psi + m\beta \psi −\left(\psi ^{⁎}\beta \psi \right)^{k}\beta \psi ,\:m > 0,\:\psi (x,t) \in \mathbb{C}^{N},\:x \in \mathbb{R}^{n},\:k \in \mathbb{N}.

We study the point spectrum of linearizations at small amplitude solitary waves in the limit

\omega \rightarrow m

, proving that if

k > 2/ n

, then one positive and one negative eigenvalue are present in the spectrum of the linearizations at these solitary waves with

ω

sufficiently close to

m

, so that these solitary waves are linearly unstable. The approach is based on applying the Rayleigh–Schrödinger perturbation theory to the nonrelativistic limit of the equation. The results are in formal agreement with the Vakhitov–Kolokolov stability criterion.

Nous considérons l'équation de Dirac non linéaire, aussi connue comme modèle de Soler. Nous étudions le spectre ponctuel des linéarisations autour d'ondes solitaires de petite amplitude dans la limite

\omega \rightarrow m

, et montrons que si

k > 2/ n

une valeur propre positive et une négative sont présentes dans le spectre des linéarisations autour de ces ondes solitaires lorsque

ω

est suffisamment proche de

m

, ce qui entraîne que ces ondes solitaires sont linéairement instables. L'approche est basée sur l'application de la théorie des perturbations de Rayleigh–Schrödinger à la limite non relativiste de l'équation. Les résultats sont en accord formel avec le critère de stabilité de Vakhitov–Kolokolov.
Flow of a viscous nematic fluid around a sphere
Authors: Gómez-González Manuel , del Álamo Juan C.
Published: June 2013

We analyse the creeping flow generated by a spherical particle moving through a viscous fluid with nematic directional order, in which momentum diffusivity is anisotropic and which opposes resistance to bending. Specifically, we provide closed-form analytical expressions for the response function, i.e. the equivalent to Stokes’s drag formula for nematic fluids. Particular attention is given to the rotationally pseudo-isotropic condition defined by zero resistance to bending, and to the strain pseudo-isotropic condition defined by isotropic momentum diffusivity. We find the former to be consistent with the rheology of biopolymer networks and the latter to be closer to the rheology of nematic liquid crystals. These ‘pure’ anisotropic conditions are used to benchmark existing particle tracking microrheology methods that provide effective directional viscosities by applying Stokes’s drag law separately in different directions. We find that the effective viscosity approach is phenomenologically justified in rotationally isotropic fluids, although it leads to significant errors in the estimated viscosity coefficients. On the other hand, the mere concept of directional effective viscosities is found to be misleading in fluids that oppose an appreciable resistance to bending. Finally, we observe that anisotropic momentum diffusivity leads to asymmetric streamline patterns displaying enhanced (reduced) streamline deflection in the directions of lower (higher) diffusivity. The bending resistance of the fluid is found to modulate the asymmetry of streamline deflection. In some cases, the combined effects of both anisotropy mechanisms leads to streamline patterns that converge towards the sphere.
Reflections on dissipation associated with thermal convection
Authors: Alboussière Thierry , Ricard Yanick
Published: June 2013

Buoyancy-driven convection is modelled using the Navier–Stokes and entropy equations. It is first shown that the coefficient of heat capacity at constant pressure, ${c}_{p} $, must in general depend explicitly on pressure (i.e. is not a function of temperature alone) in order to resolve a dissipation inconsistency. It is shown that energy dissipation in a statistically steady state is the time-averaged volume integral of $- \mathrm{D} P/ \mathrm{D} t$ and not that of $- \alpha T(\mathrm{D} P/ \mathrm{D} t)$. Secondly, in the framework of the anelastic equations derived with respect to the adiabatic reference state, we obtain a condition when the anelastic liquid approximation can be made, $\gamma - 1\ll 1$, independent of the dissipation number.
The Marlborough Mound, Wiltshire. A Further Neolithic Monumental Mound by the River Kennet
Authors: Leary Jim , Canti Matthew , Field David , Fowler Peter , Marshall Peter , Campbell Gill
Published: June 2013

Recent radiocarbon dates obtained from two soil cores taken through the Marlborough Castle mound, Wiltshire, show the main body of it to be a contemporaneous monument to Silbury Hill, dating to the second half of the 3rd millennium calbc. In light of these dates, this paper considers the sequence identified within the cores, which includes two possible flood events early in the construction of the mound. It also describes four cores taken through the surrounding ditch, as well as small-scale work to the north-east of the mound. The topographic location of the mound in a low-lying area and close to rivers and springs is discussed, and the potential for Late Neolithic sites nearby is set out, with the land to the south of the mound identified as an area for future research. The paper ends with the prospect that other apparent mottes in Wiltshire and beyond may well also have prehistoric origins
Reduced-energy cranberry juice increases folic acid and adiponectin and reduces homocysteine and oxidative stress in patients with the metabolic syndrome
Authors: Simão Tathiana Name Colado , Lozovoy Marcell Alysson Batisti , Simão Andréa Name Colado , Oliveira Sayonara Rangel , Venturini Danielle , Morimoto Helena Kaminami , Miglioranza Lúcia Helena Silva , Dichi Isaias
Published: June 2013

The metabolic syndrome (MetS) comprises pathological conditions that include insulin resistance, arterial hypertension, visceral adiposity and dyslipidaemia, which favour the development of CVD. Some reports have shown that cranberry ingestion reduces cardiovascular risk factors. However, few studies have evaluated the effect of this fruit in subjects with the MetS. The objective of the present study was to assess the effect of reduced-energy cranberry juice consumption on metabolic and inflammatory biomarkers in patients with the MetS, and to verify the effects of cranberry juice concomitantly on homocysteine and adiponectin levels in patients with the MetS. For this purpose, fifty-six individuals with the MetS were selected and divided into two groups: control group (n36) and cranberry-treated group (n20). After consuming reduced-energy cranberry juice (0·7 litres/d) containing 0·4 mg folic acid for 60 d, the cranberry-treated group showed an increase in adiponectin (P= 0·010) and folic acid (P= 0·033) and a decrease in homocysteine (P< 0·001) in relation to baseline values and also in comparison with the controls (P< 0·05). There was no significant change in the pro-inflammatory cytokines TNF-α, IL-1 and IL-6. In relation to oxidative stress measurements, decreased (P< 0·05) lipoperoxidation and protein oxidation levels assessed by advanced oxidation protein products were found in the cranberry-treated group when compared with the control group. In conclusion, the consumption of cranberry juice for 60 d was able to improve some cardiovascular risk factors. The present data reinforce the importance of the inverse association between homocysteine and adiponectin and the need for more specifically designed studies on MetS patients.
COULD PARENTAL RULES PLAY A ROLE IN THE ASSOCIATION BETWEEN SHORT SLEEP AND OBESITY IN YOUNG CHILDREN?
Authors: JONES CAROLINE H. D. , POLLARD TESSA M. , SUMMERBELL CAROLYN D. , BALL HELEN
Published: June 2013

Short sleep duration is associated with obesity in young children. This study develops the hypothesis that parental rules play a role in this association. Participants were 3-year-old children and their parents, recruited at nursery schools in socioeconomically deprived and non-deprived areas of a North-East England town. Parents were interviewed to assess their use of sleep, television-viewing and dietary rules, and given diaries to document their child's sleep for 4 days/5 nights. Children were measured for height, weight, waist circumference and triceps and subscapular skinfold thicknesses. One-hundred and eight families participated (84 with complete sleep data and 96 with complete body composition data). Parental rules were significantly associated together, were associated with longer night-time sleep and were more prevalent in the non-deprived-area compared with the deprived-area group. Television-viewing and dietary rules were associated with leaner body composition. Parental rules may in part confound the association between night-time sleep duration and obesity in young children, as rules cluster together across behavioural domains and are associated with both sleep duration and body composition. This hypothesis should be tested rigorously in large representative samples.
Evaluating the relevance of dosimetric considerations to patient instructions regarding skin care during radiation therapy
Authors: Morley Lyndon , Cashell Angela , Sperduti Annette , McQuestion Maurene , Chow James C. L.
Published: June 2013

Introduction

Patient teaching in radiation therapy may include restrictions on applying skin products owing to concerns that the presence of such materials may increase skin dose. These restrictions may create unnecessarily complicated and conflicting self-care instructions.

Purpose

To determine what thickness of skin product is necessary to produce a clinically meaningful dose increase to the skin, and provide recommendations for evidence-based patient instructions.

Methods

Dosimetric measurements and Monte Carlo simulations were used to calculate skin dose under 0–1·5 mm thicknesses of two common classes of skin product for a variety of treatment geometries. The thickness of product required to produce a clinically significant dose increase to the skin was determined.

Results

The thickness of product required to create a clinically meaningful dose increase was >0·7 mm for 10 × 10 cm2fields and >1·5 mm for 1 × 1 cm2fields. A typical application of product would be only 0·3 mm.

Conclusion

It seems unrealistic to anticipate patients using sufficiently large quantities of skin product to be of clinical concern. We therefore recommend that there are no dosimetric reasons to restrict the use of these types of skin products during radiation therapy for common treatment scenarios.
Association of qLTG3-1 with germination stage cold tolerance in diverse rice germplasm from the Indian subcontinent
Authors: Challam Clarissa , Kharshing Gayle Alisha , Yumnam Julia S. , Rai Mayank , Tyagi Wricha
Published: June 2013

Low temperature is a major constraint for crop productivity. To cope with this challenge, plants have developed several mechanisms to adapt to low temperature. Developing breeding strategies to enhance cold stress tolerance in crops requires an understanding of the mechanisms by which plants perceive and transmit cold stress-related signals to their cellular machinery, thereby activating adaptive responses. Only one quantitative trait locus for tolerance to low-temperature germination, qLTG3-1, has been narrowed down to the gene level in rice. A 71 bp indel that can be used to distinguish between tolerant and susceptible parents has been identified. We tested the 71 bp indel on 65 diverse rice genotypes including those adapted to colder climates of North and Northeastern India to find evidence of the tolerant allele (insertion) and to see whether it is associated with low-temperature germinability in these genotypes. Our results show that 48% of the rice genotypes tested carried the tolerant allele. The insertion was found to be significantly associated with cold tolerance during germination. Moreover, several landraces/improved varieties known for their superior performance in other abiotic stress conditions such as drought and high salinity conditions, and which were previously never exposed to low temperature, carry the beneficial allele for qLTG3-1, suggesting an additional role of this allele in adverse climatic conditions. This study enhances current understanding of the distribution of the tolerant allele qLTG3-1 in rice germplasm, which could help in the identification of suitable donors for potential marker-assisted breeding programmes.
Network quantification of EGFR signaling unveils potential for targeted combination therapy
Authors: Klinger Bertram , Sieber Anja , Fritsche‐Guenther Raphaela , Witzel Franziska , Berry Leanne , Schumacher Dirk , Yan Yibing , Durek Pawel , Merchant Mark , Schäfer Reinhold , Sers Christine , Blüthgen Nils
Published: June 2013

The epidermal growth factor receptor (EGFR) signaling network is activated in most solid tumors, and small‐molecule drugs targeting this network are increasingly available. However, often only specific combinations of inhibitors are effective. Therefore, the prediction of potent combinatorial treatments is a major challenge in targeted cancer therapy. In this study, we demonstrate how a model‐based evaluation of signaling data can assist in finding the most suitable treatment combination. We generated a perturbation data set by monitoring the response of RAS/PI3K signaling to combined stimulations and inhibitions in a panel of colorectal cancer cell lines, which we analyzed using mathematical models. We detected that a negative feedback involving EGFR mediates strong cross talk from ERK to AKT. Consequently, when inhibiting MAPK, AKT activity is increased in an EGFR‐dependent manner. Using the model, we predict that in contrast to single inhibition, combined inactivation of MEK and EGFR could inactivate both endpoints of RAS, ERK and AKT. We further could demonstrate that this combination blocked cell growth in BRAF‐ as well as KRAS‐mutated tumor cells, which we confirmed using a xenograft model.
The physical interaction of Mcm10 with Cdc45 modulates their DNA-binding properties
Authors: Di Perna Roberta , Aria Valentina , De Falco Mariarosaria , Sannino Vincenzo , Okorokov Andrei L. , Pisani Francesca M. , De Felice Mariarita
Published: June 2013

The eukaryotic DNA replication protein Mcm10 (mini-chromosome maintenance 10) associates with chromatin in early S-phase and is required for assembly and function of the replication fork protein machinery. Another essential component of the eukaryotic replication fork is Cdc45 (cell division cycle 45), which is required for both initiation and elongation of DNA replication. In the present study we characterize, for the first time, the physical and functional interactions of human Mcm10 and Cdc45. First we demonstrated that Mcm10 and Cdc45 interact in cell-free extracts. We then analysed the role of each of the Mcm10 domains: N-terminal, internal and C-terminal (NTD, ID and CTD respectively). We have detected a direct physical interaction between CTD and Cdc45 by both in vitro co-immunoprecipitation and surface plasmon resonance experiments. On the other hand, we have found that the interaction of the Mcm10 ID with Cdc45 takes place only in the presence of DNA. Furthermore, we found that the isolated ID and CTD domains are fully functional, retaining DNA-binding capability with a clear preference for bubble and fork structures, and that they both enhance Cdc45 DNA-binding affinity. The results of the present study demonstrate that human Mcm10 and Cdc45 directly interact and establish a mutual co-operation in DNA binding.
Numerical observability method for optimal phasor measurement units placement using recursive Tabu search method
Authors: Koutsoukis Nikolaos C. , Manousakis Nikolaos M. , Georgilakis Pavlos S. , Korres George N.
Published: June 2013

Phasor measurement units (PMUs) are essential tools for monitoring, protection and control of power systems. The optimal PMU placement (OPP) problem refers to the determination of the minimal number of PMUs and their corresponding locations in order to achieve full network observability. This paper introduces a recursive Tabu search (RTS) method to solve the OPP problem. More specifically, the traditional Tabu search (TS) metaheuristic algorithm is executed multiple times, while in the initialisation of each TS the best solution found from all previous executions is used. The proposed RTS is found to be the best among three alternative TS initialisation schemes, in regard to the impact on the success rate of the algorithm. A numerical method is proposed for checking network observability, unlike most existing metaheuristic OPP methods, which are based on topological observability methods. The proposed RTS method is tested on the IEEE 14, 30, 57 and 118‐bus test systems, on the New England 39‐bus test system and on the 2383‐bus power system. The obtained results are compared with other reported PMU placement methods. The simulation results show that the proposed RTS method finds the minimum number of PMUs, unlike earlier methods which may find either the same or even higher number of PMUs.
Three‐dimensional positioning from Google street view panoramas
Authors: Tsai Victor J.D. , Chang Chun‐Ting
Published: June 2013

Location‐based services (LBS) on web‐based maps and images have come into real‐time since Google launched its street view imaging services in 2007. This research employs Google Maps API and Web Service, GAE for JAVA, AJAX, Proj4js, cascading style sheets and HyperText markup language in developing a platform for accessing the orientation parameters of Google street view (GSV) panoramas in order to determine the three‐dimensional (3D) position of points of interest (POIs) by intersection between two nearby GSV images and to validate the 3D position of a GSV panorama by resection from three known POIs. Extracted 3D positional information of the features are then packed in keyhole markup language format and stored in GAE Servlet for future LBS applications integrated with Google Maps and Google Earth. Experimental results from two tests on intersection and one test on resection of GSV panoramas in National Chung Hsing University campus were examined with error reports and source analyses. With automatic conjugate image‐matching capability, the developed system is suitable for volumetric data collection in establishing web‐based LBS applications integrated with GSV panoramas and Google Maps/Earth in which positional accuracy is not primarily concerned.
Image segmentation by a new weighted Student's t‐mixture model
Authors: Zhang Hui , Wu Qing Ming Jonathan , Nguyen Thanh Minh
Published: June 2013

In this study, the authors introduce a new weighted Student's t‐mixture model (WSMM) for image segmentation. Gaussian distribution and Student's t‐distribution are the two commonly used probabilities in the finite mixture model (FMM). The Student's t‐mixture model has come to be regarded as an alternative to Gaussian mixture models, as it is heavily tailed and more robust for outliers. Moreover, the pixels are considered independent of each other in the FMM. Although some existing methods incorporate the spatial relationship between neighbouring pixels, they do not consider the relationship between spatial information and clustering information, thus those reported methods remain sensitive to noise. The advantages of the authors method are as follows: first, the authors introduce WSMM to incorporate the local spatial information, pixel intensity value and clustering information in an image. Second, the authors model is simple, easy to implement and has a good balance between noise insensitiveness and image detail preservation. Third, they adopt the gradient method and expectation maximisation algorithm, which allow for simultaneous estimation of optimal parameters. Finally, the most useful statistical tool for image segmentation, the well‐known hidden Markov random field model, is a special case of their model. Thus, their method is general enough for model‐based techniques construction. Experimental results on synthetic and real images demonstrate the improved robustness and effectiveness of their approach.
Guided image filtering using signal subspace projection
Authors: Zhang Yong‐Qin , Ding Yu , Liu Jiaying , Guo Zongming
Published: June 2013

There are various image filtering approaches in computer vision and image processing that are effective for some types of noise, but they invariably make certain assumptions about the properties of the signal and/or noise which lack the generality for diverse image noise reduction. This study describes a novel generalised guided image filtering method with the reference image generated by signal subspace projection (SSP) technique. It adopts refined parallel analysis with Monte Carlo simulations to select the dimensionality of signal subspace in the patch‐based noisy images. The noiseless image is reconstructed from the noisy image projected onto the significant eigenimages by component analysis. Training/test image are utilised to determine the relationship between the optimal parameter value and noise deviation that maximises the output peak signal‐to‐noise ratio (PSNR). The optimal parameters of the proposed algorithm can be automatically selected using noise deviation estimation based on the smallest singular value of the patch‐based image by singular value decomposition (SVD). Finally, we present a quantitative and qualitative comparison of the proposed algorithm with the traditional guided filter and other state‐of‐the‐art methods with respect to the choice of the image patch and neighbourhood window sizes.
Active contour driven by local divergence energies for ultrasound image segmentation
Authors: Yuan Jianjun
Published: June 2013

In this study, a new local region‐based active contour model in a variational level set formulation for ultrasound image segmentation is proposed. The energy function is formulated based on the local divergence with likelihood ratio. The proposed model can handle blurry boundaries and noise problems. In addition, the regularity of the level set function is intrinsically preserved by the level set regularisation term to ensure accurate computation. The authors only adopt a level set function to define the partition of image domain into two disjoined regions. Experimental results demonstrate desirable performance of the authors’ method for synthetic images with different level noise and ultrasound images with weak boundaries and noise.
Experimental characterisation of ultra‐wideband off‐body radio channels considering antenna effects
Authors: Khan Mohammad Monirujjaman , Abbasi Qammer Hussain , Alomainy Akram , Hao Yang , Parini Clive
Published: June 2013

Experimental investigation to characterise the ultra‐wideband (UWB) off‐body radio propagation channel for body‐centric wireless communication is presented. The measurements were performed in an indoor environment using active UWB wireless tags. Two different kinds of receiver antennas have been used; namely a small form factor (SFF) antenna and miniaturised co‐planar waveguide‐fed tapered slot antenna to investigate their effects on the radio channel behaviour. Statistical analysis is performed on the radio channel data and the results demonstrated that the lognormal distribution provides the best fit for off‐body propagation channel path‐loss models. Comparison of results shows that a reduction of 29% path‐loss exponent is noticed for the SFF antenna. In addition to this, second‐order channel parameters such as fade probability, level‐crossing rate and average fade duration are also investigated and compared for the two antennas.
Theory and experiment of wideband tunable forced‐mode ring resonator
Authors: Chen Jian‐Xin , Zhou Li‐Heng , Tang Hui , Bao Zhi‐Hua , Xue Quan
Published: June 2013

For the first time a novel wideband tunable forced‐mode ring resonator is proposed, which consists of a half guided‐wavelength (λg/2) ring resonator and two loading capacitors with different values. By controlling the respective values of the two capacitors, the fundamental resonant frequency (ffund) of the proposed ring resonator can be shifted up and down, resulting in a bi‐directional tuning of ffund. With this new design, the tuning range of ffund can then be significantly extended to approximately double the range of the conventional tunable ring resonator. Meanwhile, no other resonance occurs in the wideband frequency‐tuning range of ffund. The design equations of the proposed ring resonator are derived by using odd‐ and even‐mode analysis, and the operating principle is investigated and presented. For demonstration, the proposed tunable technique is verified by the simulation and experiment, and the measured tuning range of ffund reaches 1.25 octaves, that is 0.68 → 1.53 GHz.
Driven eigenproblem computation in periodic structures accelerated with Brent's method
Authors: Chen Huanlei , Eibert Thomas F. , Che Wenquan
Published: June 2013

The driven eigenproblem computation opens up the possibility to solve eigenproblems as excitation problems by utilising the analogy to resonators, especially for periodic structures like substrate integrated waveguides or metamaterials which can be modelled as a unit cell. The eigenvalue (wavevector, resonance frequency) can be efficiently searched by monitoring a field observable, for example, based on the electric field or the transmitted power. Therefore, the eigenvalue searching procedure can be converted to a maximisation of the observable over the complex plane of the wavevector at each frequency. The Brent's and Powell's method are employed to accelerate the maximisation. A grounded corrugated leaky‐wave antenna is analysed in both infinite‐ and finite‐width cases to verify the method. As a further example, a doubly periodic mushroom struture is analysed.
Small‐size printed coupled‐fed antenna for eight‐band LTE/GSM/UMTS wireless wide area network operation in an internal mobile handset
Authors: Ban Yong‐Ling , Chen Jin‐Hua , Li Joshua Le‐Wei , Wu Yujiang
Published: June 2013

A simple small‐size printed antenna for eight‐band long‐term evolution (LTE)/GSM/UMTS wireless wide area network operation in an internal mobile handset application is proposed. Occupying a compact size of 15 × 40 mm2 on the ungrounded region of the system circuit board and a low profile of 4 mm, the presented antenna is a coupled‐fed configuration. With the longer branch of the feeding strip, a λ/4 resonant mode at around 2.7 GHz can be obtained to cover the desired LTE2500 operation. A fundamental λ/4 resonant mode over the desired lower band of LTE700/GSM850/900 can also be generated at 750 MHz by the long meandered coupling strip (length of about 113 mm). Moreover, two additional higher‐order resonant modes at around 1.75 and 2.25 GHz can also be obtained by the coupling strip. By including a chip inductor L at the feeding point, the impedance matching over the lower and upper bands can be improved in order to achieve the two wide operating bands of 698–960 and 1710–2690 MHz. With the following properties of small size, ease of fabrication and good radiation characteristics, the proposed antenna is a good candidate for the fourth LTE mobile phone applications.
Optimisation of antenna arrays using the cuckoo search algorithm
Authors: Khodier Majid
Published: June 2013

The goal of this article is to introduce and use the cuckoo search (CS) as an optimisation algorithm for the electromagnetics and antenna community. The CS is a new nature‐inspired evolutionary algorithm (EA) for solving N‐dimensional optimisation problems. Compared with other nature‐inspired algorithms, the CS algorithm is easy to understand and implement and has minimum number of parameters to tune. Different examples are presented that illustrate the use of the CS algorithm, and the results are compared with results obtained using other optimisation methods. Preliminary results suggest that the CS algorithm can in some cases outperform other EAs, at least for the examples studied in this article.
Second cohomology of q-deformed Witt superalgebras
Authors: Ammar Faouzi , Makhlouf Abdenacer , Saadaoui Nejib
Published: June 2013

The purpose of this paper is to compute the second adjoint cohomology group of q-deformed Witt superalgebras. They are Hom-Lie superalgebras obtained by q-deformation of Witt Lie superalgebra, that is one considers σ-derivations instead of classical derivations.
Influence of thin interphase on magnetoelectric effect of coated cylindrical fibrous multiferroic composites
Authors: Yue Y. M. , Xu K. Y.
Published: June 2013

The work reported in this paper aims at studying the magneto-electric field variation accounting for a thin interphase layer with different materials. Thin interphase within a solid can significantly affect the overall response of the composite material. In order to obtain this phenomenon, we replace the interphase by an imperfect interface with appropriately devised interface conditions. To get the interface conditions, a Taylor expansion of the relevant physical fields in the thin region is introduced. Those conditions do not involve the fields within the interphase, which just have relation to the material properties and the fields of the adjacent media. Finally, the influence of the thin interphase on the performance of fibrous multiferroic composites is analyzed in detail by using our method and some useful conclusions are summarized.
Gas-phase electronic spectroscopy of the indene cation (C9H8+)
Authors: Chalyavi Nahid , Dryza Viktoras , Sanelli Julian A. , Bieske Evan J.
Published: June 2013

The electronic spectrum of the indene radical cation has been investigated through resonance-enhanced photodissociation of the weakly bound C9H8+–He and C9H8+–Arn (n = 1, 2) complexes in a tandem mass spectrometer. The D2 ← D0 band origin for indene+–He is observed at 17 379 ± 15 cm−1, while the D2 ← D0 and D4 ← D0 band origins for indene+–Ar appear at 17 353 ± 15 cm−1 and 28 254 ± 15 cm−1, respectively. The vibronic structure of the D2 ← D0 band system is assigned by comparison with a simulated spectrum based on time-dependent density functional theory calculations, and is due mainly to progressions in ring deformation vibrational modes. Possible correspondences between the stronger visible transitions of the indene cation and diffuse interstellar bands observed towards the heavily reddened star HD 204827 are discussed.
On the electrical behavior of V2O5/4H-SiC Schottky diodes
Authors: Bellone S. , Di Benedetto L. , Rubino A.
Published: June 2013

A complete analysis of the rectifying behavior of V2O5/4H-SiC (divanadium pentoxide/4H polytype of silicon carbide) junction is reported. The analysis of forward and reverse JD−VD curves of samples fabricated with 5 nm-thick V2O5 films shows that the carrier transport across junction is dominated by the field enhanced thermionic emission mechanism. All the physical and electrical parameters, such as Schottky barrier height, ideality factor, and series resistance, have been evaluated from temperature behavior of JD−VD curves in the range 100–425 K and from CD−VD measurements. It is shown that the barrier height extracted from measurements can be justified in terms of inhomogeneities localized at the interface.
Surface deformation effects induced by radiation pressure and electrostriction forces in dielectric solids
Authors: Astrath N. G. C. , Lukasievicz G. V. B. , Malacarne L. C. , Bialkowski S. E.
Published: June 2013

The surface displacement produced by radiation pressure and electrostriction forces is investigated considering the commonly accepted theories proposed by Minkowski and Abraham for the energy-momentum tensor. The contributions are modeled considering each effect separately assuming non-absorbing and absorbing solids and the thermoelastic deformation equations are solved numerically. We show that the surface deformation profiles as calculated by the Minkowski or Abraham momenta give different surface curvature, which could in principle be detected by measuring the surface displacement. Finally, an all-optical pump-probe photothermal method to detect the radiation pressure and electrostriction forces in transparent dielectric solids is proposed.
Bandgaps in the deep ultraviolet borate crystals: Prediction and improvement
Authors: He Ran , Huang Hongwei , Kang Lei , Yao Wenjiao , Jiang Xingxing , Lin Zheshuai , Qin Jingui , Chen Chuangtian
Published: June 2013

We identify the microscopic structural origins determining the bandgaps in the deep-ultraviolet borates, and propose an efficient method for the prediction of their bandgaps. This method considers only the chemical bond lengths around oxygen atoms and achieves the very high precision with the relative error <5% typically. Its validity is verified by the first-principles studies, which reveal the strong dependence of bandgaps on the coordination environment around oxygen atoms. Our studies have great implications on the search and design of optoelectronic functional materials with large bandgap.
Interfacial layer reduction and high permittivity tetragonal ZrO2 on germanium reaching ultrathin 0.39 nm equivalent oxide thickness
Authors: Lin Cheng-Ming , Chang Hung-Chih , Wong I-Hsieh , Luo Shih-Jan , Liu C. W. , Hu Chenming
Published: June 2013

The nearly free interfacial layer and the tetragonal phase ZrO2 with the high permittivity of 45 ± 3 on Ge (001) substrate lead to the equivalent oxide thickness as low as 0.39 nm and the low leakage current density of 2 × 10−3 A/cm−2. The ultrathin GeON layer formed by remote plasma treatment on GeO2/Ge can inhibit the interfacial layer regrowth by retarding the interdiffusion of Ge and O atoms. The initial ∼1 nm GeO2 layer is consumed during the remote plasma treatment, confirmed by x-ray photoelectron spectroscopy and further thinned down by post-deposition annealing to trigger the GeO desorption.
BACE2 processes PMEL to form the melanosome amyloid matrix in pigment cells
Authors: Rochin Leila , Hurbain Ilse , Serneels Lutgarde , Fort Cecile , Watt Brenda , Leblanc Pascal , Marks Michael S. , De Strooper Bart , Raposo Graça , van Niel Guillaume
Published: June 2013

Amyloids are often associated with pathologic processes such as in Alzheimer’s disease (AD), but can also underlie physiological processes such as pigmentation. Formation of pathological and functional amyloidogenic substrates can require precursor processing by proteases, as exemplified by the generation of Aβ peptide from amyloid precursor protein (APP) by beta-site APP cleaving enzyme (BACE)1 and γ-secretase. Proteolytic processing of the pigment cell-specific Melanocyte Protein (PMEL) is also required to form functional amyloid fibrils during melanogenesis, but the enzymes involved are incompletely characterized. Here we show that the BACE1 homologue BACE2 processes PMEL to generate functional amyloids. BACE2 is highly expressed in pigment cells and
Bace2
−/−
but not
Bace1
−/−
mice display coat color defects, implying a specific role for BACE2 during melanogenesis. By using biochemical and morphological analyses, combined with RNA silencing, pharmacologic inhibition, and BACE2 overexpression in a human melanocytic cell line, we show that BACE2 cleaves the integral membrane form of PMEL within the juxtamembrane domain, releasing the PMEL luminal domain into endosomal precursors for the formation of amyloid fibrils and downstream melanosome morphogenesis. These studies identify an amyloidogenic substrate of BACE2, reveal an important physiological role for BACE2 in pigmentation, and highlight analogies in the generation of PMEL-derived functional amyloids and APP-derived pathological amyloids.
Key ornamental innovations facilitate diversification in an avian radiation
Authors: Maia Rafael , Rubenstein Dustin R. , Shawkey Matthew D.
Published: June 2013

Patterns of biodiversity are often explained by ecological processes, where traits that promote novel ways of interacting with the environment (key innovations) play a fundamental role in promoting diversification. However, sexual selection and social competition can also promote diversification through rapid evolution of ornamental traits. Because selection can operate only on existing variation, the tendency of ornamental traits to constrain or enable the production of novel phenotypes is a crucial but often overlooked aspect of diversification. Starlings are a speciose group characterized by diverse iridescent colors produced by nanometer-scale arrays of melanin-containing organelles (melanosomes) that play a central role in sexual selection and social competition. We show that evolutionary lability of these colors is associated with both morphological and lineage diversification in African starlings. The solid rod-like melanosome morphology has evolved in a directional manner into three more optically complex forms that can produce a broader range of colors than the ancestral form, resulting in (i) faster color evolution, (ii) the occupation of novel, previously unreachable regions of colorspace, and ultimately (iii) accelerated lineage diversification. As in adaptive radiations, key innovations in ornament production can provide high phenotypic trait variability, leading to dramatic effects on the tempo and mode of diversification.
Orientation-specific responses to sustained uniaxial stretching in focal adhesion growth and turnover
Authors: Chen Yun , Pasapera Ana M. , Koretsky Alan P. , Waterman Clare M.
Published: June 2013

Significance

Cells are mechanosensitive: a cell’s adaptive responses to mechanical inputs will determine its morphology, gene expression, and posttranslational protein modification. Focal adhesions (FAs), the integrin-containing complexes positioned between the extracellular matrix and the cell, are key in transmitting the mechanosignal to initiate these downstream adaptive responses. In this study we made the unique observation that FA and cellular morphology changes in response to sustained uniaxial stretch are orientation specific. Our results also suggest orientation-specific responses at the molecular level in individual FAs propagate up to regulate cell morphology, which may in turn mediate adaptive responses that promote tissue growth.
Effects of oncogenic mutations on the conformational free-energy landscape of EGFR kinase
Authors: Sutto Ludovico , Gervasio Francesco Luigi
Published: June 2013

Activating mutations in the epidermal growth factor receptor (EGFR) tyrosine kinase are frequently found in many cancers. It has been suggested that changes in the equilibrium between its active and inactive conformations are linked to its oncogenic potential. Here, we quantify the effects of some of the most common single (L858R and T790M) and double (T790M-L858R) oncogenic mutations on the conformational free-energy landscape of the EGFR kinase domain by using massive molecular dynamics simulations together with parallel tempering, metadynamics, and one of the best force-fields available. Whereas the wild-type EGFR catalytic domain monomer is mostly found in an inactive conformation, our results show a clear shift toward the active conformation for all of the mutants. The L858R mutation stabilizes the active conformation at the expense of the inactive conformation and rigidifies the αC-helix. The T790M gatekeeper mutant favors activation by stabilizing a hydrophobic cluster. Finally, T790M with L858R shows a significant positive epistasis effect. This combination not only stabilizes the active conformation, but in nontrivial ways changes the free-energy landscape lowering the transition barriers.
Evolution of consciousness: Phylogeny, ontogeny, and emergence from general anesthesia
Authors: Mashour George A. , Alkire Michael T.
Published: June 2013

Are animals conscious? If so, when did consciousness evolve? We address these long-standing and essential questions using a modern neuroscientific approach that draws on diverse fields such as consciousness studies, evolutionary neurobiology, animal psychology, and anesthesiology. We propose that the stepwise emergence from general anesthesia can serve as a reproducible model to study the evolution of consciousness across various species and use current data from anesthesiology to shed light on the phylogeny of consciousness. Ultimately, we conclude that the neurobiological structure of the vertebrate central nervous system is evolutionarily ancient and highly conserved across species and that the basic neurophysiologic mechanisms supporting consciousness in humans are found at the earliest points of vertebrate brain evolution. Thus, in agreement with Darwin’s insight and the recent “Cambridge Declaration on Consciousness in Non-Human Animals,” a review of modern scientific data suggests that the differences between species in terms of the ability to experience the world is one of degree and not kind.
Oxidation of nanoscale Au–In alloy particles as a possible route toward stable Au-based catalysts
Authors: Sutter Eli A. , Tong Xiao , Jungjohann Katherine , Sutter Peter W.
Published: June 2013

The oxidation of bimetallic alloy nanoparticles comprising a noble and a nonnoble metal is expected to cause the formation of a single-component surface oxide of the nonnoble metal, surrounding a core enriched with the noble metal. Studying the room temperature oxidation of Au–In nanoparticles, we show that this simple picture does not apply to an important class of bimetallic alloys, in which the oxidation proceeds via predominant oxygen diffusion. Instead of a crystalline In
2
O
3
shell, such oxidation leads to an amorphous shell of mixed Au–In oxide that remains stable to high temperatures and whose surface layer is enriched with Au. The Au-rich mixed oxide is capable of adsorbing both CO and O
2
and converting them to CO
2
, which desorbs near room temperature. The oxidation of Au–In alloys to a mixed Au–In oxide shows significant promise as a viable approach toward Au-based oxidation catalysts, which do not require any complex synthesis processes and resist deactivation up to at least 300 °C.
Valley Chern numbers and boundary modes in gapped bilayer graphene
Authors: Zhang Fan , MacDonald Allan H. , Mele Eugene J.
Published: June 2013

Electronic states at domain walls in bilayer graphene are studied by analyzing their four- and two-band continuum models, by performing numerical calculations on the lattice, and by using quantum geometric arguments. The continuum theories explain the distinct electronic properties of boundary modes localized near domain walls formed by interlayer electric field reversal, by interlayer stacking reversal, and by simultaneous reversal of both quantities. Boundary mode properties are related to topological transitions and gap closures, which occur in the bulk Hamiltonian parameter space. The important role played by intervalley coupling effects not directly captured by the continuum model is addressed using lattice calculations for specific domain wall structures.