bluuebunny/crossref_metadata_2025 huggingface dataset:
Zonal Large-Eddy Simulation of a Fan Tip-Clearance Flow, With Evidence of Vortex Wandering
Authors: Boudet Jérôme , Cahuzac Adrien , Kausche Philip , Jacob Marc C.
Published: September 2014

The flow in a fan test-rig is studied with combined experimental and numerical methods, with a focus on the tip-leakage flow. A zonal RANS/LES approach is introduced for the simulation: the region of interest at tip is computed with full large-eddy simulation (LES), while Reynolds-averaged Navier–Stokes (RANS) is used at inner radii. Detailed comparisons with the experiment show that the simulation gives a good description of the flow. In the region of interest at tip, a remarkable prediction of the velocity spectrum is achieved, over about six decades of energy. The simulation precisely captures both the tonal and broadband contents. Furthermore, a detailed analysis of the simulation allows identifying a tip-leakage vortex (TLV) wandering, whose influence onto the spectrum is also observed in the experiment. This phenomenon might be due to excitation by upstream turbulence from the casing boundary layer and/or the adjacent TLV. It may be a precursor of rotating instability. Finally, considering the outlet duct acoustic spectrum, the vortex wandering appears to be a major contribution to noise radiation.
A method for avoiding overlap of left and right lungs in shape model guided segmentation of lungs in CT volumes
Authors: Gill Gurman , Bauer Christian , Beichel Reinhard R.
Published: September 2014

Purpose:

The automated correct segmentation of left and right lungs is a nontrivial problem, because the tissue layer between both lungs can be quite thin. In the case of lung segmentation with left and right lung models, overlapping segmentations can occur. In this paper, the authors address this issue and propose a solution for a model‐based lung segmentation method.

Methods:

The thin tissue layer between left and right lungs is detected by means of a classification approach and utilized to selectively modify the cost function of the lung segmentation method. The approach was evaluated on a diverse set of 212 CT scans of normal and diseased lungs. Performance was assessed by utilizing an independent reference standard and by means of comparison to the standard segmentation method without overlap avoidance.

Results:

For cases where the standard approach produced overlapping segmentations, the proposed method significantly (p = 1.65 × 10−9) reduced the overlap by 97.13% on average (median: 99.96%). In addition, segmentation accuracy assessed with the Dice coefficient showed a statistically significant improvement (p = 7.5 × 10−5) and was 0.9845 ± 0.0111. For cases where the standard approach did not produce an overlap, performance of the proposed method was not found to be significantly different.

Conclusions:

The proposed method improves the quality of the lung segmentations, which is important for subsequent quantitative analysis steps.
Quantifying the effect of seed orientation in postplanning dosimetry of low‐dose‐rate prostate brachytherapy
Authors: Collins Fekete Charles‐Antoine , Plamondon Mathieu , Martin André‐Guy , Vigneault Éric , Verhaegen Frank , Beaulieu Luc
Published: September 2014

Purpose:

Radioactive seed orientations are usually ignored in clinical brachytherapy dosimetry for prostate implants. Associated with the anisotropic dose distribution of seeds, these orientations could cause dose differences between the planning configurations and the clinical postplanning dosimetry. This study will quantify the impact of seed orientation on the dosimetry.

Methods:

3D seed positions and θ and φ polar angles were obtained using five independent fluoroscopic images for 287 patients. Five dose calculation methods are compared: TG43‐1D (1), TG43‐2D parallel to implant axis (2) and with orientations (3), Monte Carlo (MC) simulations parallel (4), and MC simulations with orientations (5). geant4 v4.9.6 MC simulations were made in 1 mm3 voxelized geometries based on the DICOM‐RT information. Materials were assigned using thresholds based on the HU number, as recommended in TG186 reports. Seed voxels are overridden with prostatic materials and the layered mass geometry [Enger et al., Phys. Med. Biol. 57(19), 6269–6277 (2012)] allows subsequent placement of the source geometry. 500 million histories were used per patient. 3D dose and DVHs for each structure were calculated.

Results:

The various seed orientations do not result in statistically significant differences on the dose metrics for the clinical target volume (CTV) or the urethra, based on the Student t‐test p‐value. Difference as low as −0.238% and 0.059% has been seen on the CTV D90, respectively, for the MC and the TG43. The difference between parallel and oriented calculations for the organs at risk (OARs) can differ by 2% on average.

Conclusions:

Based on the results from this study, seed orientations have no significant impact of CTV and urethra dose metrics but can affect OARs that are external to the CTV.
Medical Imaging Technology (Springer Briefs in Physics)
Authors: Bakhtiary Mohammad
Published: September 2014

Haidekker Mark A., Medical Imaging Technology (Springer Briefs in Physics) Springer, New York, NY, 2013. 129 pp. Price: $40.59. ISBN: 978‐1‐4614‐7072‐4 (paperback).
Evaluation of slice sensitivity profiles for helical and axial 4D‐CT acquisitions on the Philips Brilliance CT Big Bore
Authors: Klahr Paul
Published: September 2014

Purpose:

4D‐CT can be performed using two acquisition modes. One employs a cine axial scan and the other acquires the data using a very low pitch helical acquisition. This study evaluates the longitudinal resolutions of each of these methods by creating slice sensitivity profiles (SSP).

Methods:

An SSP phantom was scanned using both axial and helical scanning modes. The phantom was scanned at the center of the field of view (FOV) and at several points offset from the FOV center. For helical scans, the pitch was varied from 0.04 to 0.2. With the axial scans, the phantom position relative to the center of the detector ring was varied. All of these were performed using a 16 × 1.5 mm collimation.

Results:

The SSP graphs were generated from these scanned datasets. The full width at half maximum (FWHM) of the graphs was used as the surrogate for longitudinal resolution. The results of these experiments demonstrated that axial scans have a slightly better resolution at CT isocenter (1.5 vs 1.8 mm). Helical mode scanning maintained this measurement for varying pitch factors and placement with the scan field. However, the resolution for axial scans degrades as the phantom is moved further from the center of the FOV and is positioned nearer to the edge of the detector rings.

Conclusions:

When it is imperative to maintain uniform longitudinal resolution throughout the FOV, it is suggested that helical acquisition be utilized or the axial mode data be reconstructed to account for beam divergence. For axial scans, this will require either limiting the longitudinal extent of each cine axial acquisition and/or using a smaller reconstructed FOV.
Diffusion Monte Carlo: A powerful tool for studying quantum many-body systems
Authors: Pang Tao
Published: September 2014

Diffusion quantum Monte Carlo is introduced at an elementary level. We highlight the strengths of the method in addressing important issues associated with quantum many-body systems, such as those associated with the ground-state energy and pair-distribution function. 4He clusters trapped on a graphite surface are simulated as an example of the method. A sample program and documentation for developing simulation projects are provided.
Fibroblast growth factor receptor 1 is a key inhibitor of TGFβ signaling in the endothelium
Authors: Chen Pei-Yu , Qin Lingfeng , Tellides George , Simons Michael
Published: September 2014

Endothelial-to-mesenchymal transition is suppressed by FGFR1 signaling.
Establishing Memory of Gene Repression
Authors: Purnell Beverly A.
Published: September 2014

Repression is perpetuated across generations and cell divisions via methylated histones and methylating enzymes.
Treating Diabetes with FGF1
Authors: Gough Nancy R.
Published: September 2014

Studies in mice indicate that fibroblast growth factor 1 can be used as a drug to treat type 2 diabetes.
Polarized VEGF Signaling Outputs
Authors: VanHook Annalisa M.
Published: September 2014

VEGF-A induces different responses in neural microvessel endothelia depending on whether it comes from the blood or the parenchyma.
Treatment of heterotopic ossification through remote ATP hydrolysis
Authors: Peterson Jonathan R. , De La Rosa Sara , Eboda Oluwatobi , Cilwa Katherine E. , Agarwal Shailesh , Buchman Steven R. , Cederna Paul S. , Xi Chuanwu , Morris Michael D. , Herndon David N. , Xiao Wenzhong , Tompkins Ronald G. , Krebsbach Paul H. , Wang Stewart C. , Levi Benjamin
Published: September 2014

Heterotopic ossification induced by injuries and burns is mediated by signaling through the SMAD pathway and can be targeted with topical apyrase.
Clinical recovery from surgery correlates with single-cell immune signatures
Authors: Gaudillière Brice , Fragiadakis Gabriela K. , Bruggner Robert V. , Nicolau Monica , Finck Rachel , Tingle Martha , Silva Julian , Ganio Edward A. , Yeh Christine G. , Maloney William J. , Huddleston James I. , Goodman Stuart B. , Davis Mark M. , Bendall Sean C. , Fantl Wendy J. , Angst Martin S. , Nolan Garry P.
Published: September 2014

Single-cell mass cytometry revealed immune correlates of patient-associated variability in surgical recovery.
A Cancer Drug Promotes Hair Growth
Authors: Maus Marcela V.
Published: September 2014

Blockade of cytokine production with JAK-targeted drugs promotes hair growth in mice and humans with alopecia areata.
A Horizontally Acquired Transcription Factor Coordinates
Salmonella
Adaptations to Host Microenvironments
Authors: Brown Nat F. , Rogers Lindsay D. , Sanderson Kristy L. , Gouw Joost W. , Hartland Elizabeth L. , Foster Leonard J.
Published: September 2014

The transcription factors HilA and SsrB activate expression of two type III secretion systems (T3SSs) and cognate effectors that reprogram host cell functions to benefit infecting
Salmonella
in the host. These transcription factors, the secretion systems, and the effectors are all encoded by horizontally acquired genes. Using quantitative proteomics, we quantified the abundance of 2,149 proteins from
hilA
or
ssrB Salmonella in vitro
. Our results suggest that the HilA regulon does not extend significantly beyond proteins known to be involved in direct interactions with intestinal epithelium. On the other hand, SsrB influences the expression of a diverse range of proteins, many of which are ancestral to the acquisition of
ssrB
. In addition to the known regulon of T3SS-related proteins, we show that, through SodCI and bacterioferritin, SsrB controls resistance to reactive oxygen species and that SsrB down-regulates flagella and motility. This indicates that SsrB-controlled proteins not only redirect host cell membrane traffic to establish a supportive niche within host cells but also have adapted to the chemistry and physical constraints of that niche.

IMPORTANCE
Expression of T3SSs typically requires a transcription factor that is linked in a genomic island. Studies of the targets of HilA and SsrB have focused on almost exclusively on T3SS substrates that are either linked or encoded in distinct genomic islands. By broadening our focus, we found that the regulon of SsrB extended considerably beyond T3SS-2 and its substrates, while that of HilA did not. That at least two SsrB-regulated processes streamline existence in the intracellular niche afforded by T3SS-2 seems to be a predictable outcome of evolution and natural selection. However, and importantly, these are the ﬁrst such functions to be implicated as being SsrB dependent. The concept of T3SS-associated transcription factors coordinating manipulations of host cells together with distinct bacterial processes for increased efficiency has unrealized implications for numerous host-pathogen systems.
Influences on human papillomavirus (HPV)-related information needs among women having HPV tests for follow-up of abnormal cervical cytology
Authors: O'Connor Mairead , Costello Liza , Murphy Judith , Prendiville Walter , Martin Cara M , O'Leary John J , Sharp Linda
Published: September 2014

Objectives

Testing for human papillomavirus (HPV) infection has recently been introduced into cervical screening programmes. We investigated (1) barriers to accessing and absorbing information and (2) factors that influence information needs among women undergoing HPV tests.

Methods

In-depth interviews were conducted with 27 women who had HPV tests performed in a colposcopy clinic as part of follow-up of low-grade abnormal cytology or post-treatment for cervical intraepithelial neoplasia (CIN). Interviews were transcribed verbatim, coded and analysed using Framework Analysis, to identify main themes and sub-themes.

Results

Among these women, barriers to accessing and absorbing HPV information were: being overwhelmed with information; context of the HPV test; colposcopy clinic experience(s); women's perceptions of medical professionals’ behaviours and attitudes, and information available on the Internet. Factors influencing women's HPV information needs were: concerns surrounding abnormal cytology or diagnosis of CIN; amount of information provided about HPV; awareness HPV is sexually transmitted; previous negative health care experience(s); and the HPV test in relation to other life events. The timing of delivery of HPV information was key to women absorbing or remembering the information given; it was important that information was given in stages rather than altogether.

Conclusions

In women undergoing HPV testing during follow-up, the amount and timing of delivery of HPV information requires careful consideration. Significant barriers exist to accessing and absorbing HPV information which, unless addressed, could have serious implications in terms of women's comprehension of HPV tests. Given the expanding use of HPV testing within cervical screening, further research on HPV-related information issues is needed.
Structural and electronic properties of SiC/AlN core/shell nanowires: a first-principles study
Authors: Ren Junfeng , Zhang Yanru , Zhang Lin , Yuan Xiaobo , Hu Guichao
Published: September 2014

The structural stabilities and electronic properties of passivated and unpassivated SiC / AlN core/shell nanowires (CSNWs) along [0001] direction are investigated by using first-principles calculations with density functional theory. Our calculations demonstrate that thick AlN shell and small ratio of SiC core make the SiC / AlN CSNWs more stable. The band gaps decrease with the increasing of the CSNWs diameters. After passivation at the surface, type of SiC / AlN heterostructure changes and the mobility can be improved by increasing the CSNWs diameter and the SiC core ratio. These results provide an effective way to modulate the electronic properties of SiC / AlN structure, which is useful for fabrications and applications of CSNWs.
Spectroscopic and thermal properties of novel Yb3+-doped TeO2–PbO–NbO2.5 based tellurite glasses with high emission cross-section
Authors: Lin She-Bao , Wang Peng-Fei , She Jiang-Bo , Xu Shen-Nuo , Zhao Peng-Fei , Yu Cheng-Long , Liu Chun-Xiao , Peng Bo
Published: September 2014

Series of 70% TeO 2 - x% PbO – (30 - x%) NbO 2.5 (x = 0, 5, and 10 mol.%) glasses doped with Yb 2 O 3 were prepared by the melt-quenching method. Their emission cross-sections, fluorescence lifetimes and gain coefficient were investigated by the absorption spectra and the fluorescence decay curves, respectively. The results show that the glass with 10% PbO possesses the largest emission cross-section of 1.51 pm2, the fluorescence lifetime of 0.68 ms and the gain coefficient of 1.03 ms ⋅ pm 2. These indicate that this tellurite glass may have potential application as Yb 2 O 3 doped gain medium for solid laser.
Effective permeability tensor of partially magnetized two-component metaferrites
Authors: Rybin Oleg
Published: September 2014

Expressions for the effective permeability tensor of two-component partially magnetized ferrite-like metamaterials are obtained in the microwave frequency range. The formulas are based on the theory of partially saturated conventional ferrites and the effective medium theory (EMT) of metamaterials presented in a form of an infinite host dielectric medium with periodically embedded ferric cylindrical and spherical inclusions partially magnetized with an external bias DC magnetic field. The low-field losses absence conditions are obtained for the metamaterials under the assumption of a low phenomenological loss term and losses are estimated.
Ab initio calculations of Na and Ni diffusion in NaNi1/2Mn1/2O2 and NaNi1/3Mn1/3Co1/3O2 for Na-ion batteries
Authors: Shi J. J. , Yin G. Q. , Jing L. M. , Guan J. , Wu M. P. , Zhou Y. L. , Lou H. L. , Wang Zhiguo
Published: September 2014

In this paper, sodium and nickel ion dynamics in layered cathode materials of NaNi 1/2 Mn 1/2 O 2 and NaNi 1/3 Mn 1/3 Co 1/3 O 2 for Na -ion battery applications were investigated using first principles based on density functional theory. The diffusion pathways for sodium and nickel migration inside the layered cathode materials were optimized and their energy barriers were calculated based on the nudged elastic band method. The energy barrier of Na diffusion in NaNi 1/2 Mn 1/2 O 2 and NaNi 1/3 Mn 1/3 Co 1/3 O 2 is about 1.0 eV. However, when the Ni is located at the Na layer, i.e. occupying the Na position, the energy barrier for Ni diffusion inside the layered cathode materials is about 0.36 eV, which indicates that Ni will diffuse to the surface of electrode materials, thus will block or slow down the sodium diffusion, limiting the battery performance.
Multiplierless Multiple-Stage Cascaded FIR Filter Design
Authors: Ye Wenbin
Published: September 2014

It is well known that multiplierless finite impulse response (FIR) filters in multiple-stage cascade form can achieve lower hardware cost and lower coefficient sensitivity than that of single stage design. In this work, a novel algorithm is proposed for the design of multiplierless multiple-stage cascaded FIR filters. Unlike to the conventional algorithms in which the number of stages is fixed and usually is fixed to two, the number of stage in the proposed algorithm is automatically determined. The design examples show that the proposed algorithm significantly outperforms the best existing algorithm in terms of hardware cost and the design time is also saved.
TOPOLOGY-PRESERVING WATERMARKING OF VECTOR GRAPHICS
Authors: HUBER STEFAN , HELD MARTIN , MEERWALD PETER , KWITT ROLAND
Published: September 2014

Watermarking techniques for vector graphics dislocate vertices in order to embed imperceptible, yet detectable, statistical features into the input data. The embedding process may result in a change of the topology of the input data, e.g., by introducing self-intersections, which is undesirable or even disastrous for many applications. In this paper we present a watermarking framework for two-dimensional vector graphics that employs conventional watermarking techniques but still provides the guarantee that the topology of the input data is preserved. The geometric part of this framework computes so-called maximum perturbation regions (MPR) of vertices. We propose two efficient algorithms to compute MPRs based on Voronoi diagrams and constrained triangulations. Furthermore, we present two algorithms to conditionally correct the watermarked data in order to increase the watermark embedding capacity and still guarantee topological correctness. While we focus on the watermarking of input formed by straight-line segments, one of our approaches can also be extended to circular arcs. We conclude the paper by demonstrating and analyzing the applicability of our framework in conjunction with two well-known watermarking techniques.
Nonlinear Flutter of Laminated Composite Plates Resting on Nonlinear Elastic Foundations Using Homotopy Perturbation Method
Authors: Yazdi Ali A.
Published: September 2014

In this paper, the applicability of the homotopy perturbation method (HPM) in analyzing the flutter of geometrically nonlinear cross-ply rectangular laminated plates resting on nonlinear elastic foundation is investigated. The piston theory is employed to evaluate the aerodynamic pressure acting on the plate. The von Karman geometric nonlinear theory is used to construct the governing equations of the system. The Galerkin's method is used to reduce the nonlinear partial differential equations to a nonlinear second-order ordinary differential equation, and the HPM is employed to study the effect of initial deflection, aspect ratio and stacking sequence on the flutter pressure of cross-ply laminated plates. The results show that the first approximation of the HPM leads to highly accurate solutions for the geometrically nonlinear flutter of cross-ply rectangular laminated plates subjected to the aerodynamic pressure.
In-Plane Nonlinear Buckling of Funicular Arches
Authors: Zhu Jianbei , Attard Mario M. , Kellermann David C.
Published: September 2014

This paper presents a numerical technique to determine the full pre-buckling and post-buckling equilibrium path for elastic funicular arches. The formulation includes the effects of shear deformations and geometric nonlinearity due to large deformations. The Timoshenko beam hypothesis is adopted for incorporating shear. Finite strains are considered without approximation. The finite strains are defined in terms of the normal and shear component of the longitudinal stretch. The constitutive relations for the internal actions are based on a hyperelastic constitutive model. Using the differential equilibrium equations and the constitutive laws, the nonlinear buckling behavior of some typical funicular arches are investigated using the trapezoid method with Richardson extrapolation enhancement. The results are validated by using the finite element package ANSYS and solutions available in the literature. Examples include parabolic arches under a uniformly distributed gravity load, a catenary under a distributed load along the arch and a catenary arch under an overburden load. Parametric studies are performed to identify the factors that influence the nonlinear buckling of funicular arches. The axial to shear rigidity ratio is shown to have a significant effect on the buckling load and the buckling mode shape.
A Preliminary Investigation into the Effect of Outlier(s) on Singular Spectrum Analysis
Authors: Hassani Hossein , Mahmoudvand Rahim , Omer Hardi Nabe , Silva Emmanuel Sirimal
Published: September 2014

The aim of this paper is to study the effect of outliers on different parts of singular spectrum analysis (SSA) from both theoretical and practical points of view. The rank of the trajectory matrix, the magnitude of eigenvalues, reconstruction, and forecasting results are evaluated using simulated and real data sets. The performance of both recurrent and vector forecasting procedures are assessed in the presence of outliers. We find that the existence of outliers affect the rank of the matrix and increases the linear recurrent dimensions whilst also having a significant impact on SSA reconstruction and forecasting processes. There is also evidence to suggest that in the presence of outliers, the vector SSA forecasts are more robust in comparison to the recurrent SSA forecasts. These results indicate that the identification and removal of the outliers are mandatory to achieve optimal SSA decomposition and forecasting results.
Molecular Dynamics Analysis on Compressive Strength of PAN-Based Carbon Fibers
Authors: Okamoto Shingo , Ito Akihiko
Published: September 2014

We investigated the compressive strength of PAN-based carbon fibers containing both amorphous and crystalline structures using molecular dynamics simulations. In addition, we investigated the buckling behavior of graphene and graphite crystals under compressive loading. The calculated buckling stresses of those crystals with different aspect ratios agree well with the results by the Euler's buckling theory. We finally found that the compressive strength of the PAN-based carbon fiber with a large amount of amorphous structures was 11 GPa. Moreover, a fracture of the PAN-based carbon fiber begins due to the buckling of carbon layers in crystallites, and propagates with the shear slipping in the crystallites. On the other hand, the compressive strength of the carbon fiber with a small amount of amorphous structures was only 2 GPa. Thus, it was found that the amorphous structure significantly affects the compressive strength of PAN-based carbon fibers.
Development of Dye-Sensitized Solid-State ZnO/D149/CuSCN Solar Cell
Authors: Ranasinghe C. S. K. , Jayaweera E. N. , Kumara G. R. A. , Bandara H. M. N. , Rajapakse R. M. G.
Published: September 2014

Dye-sensitized solid-state solar cells (DSSC) based on n-type ZnO and p-type CuSCN have been fabricated with highest recorded power conversion efficiency. The working electrode of the cell is composed of D149 dye-coated ZnO -based interconnected nanoparticulate (20 nm) mesoporous layer with ZnO -based dense layer which was prepared on fluorine-doped tin oxide (FTO) glass substrates. CuSCN deposition was carried out according to the previously reported procedure which ensures enhanced p-type conductivity of CuSCN . The surface morphologies of the ZnO dense layer, ZnO porous layer and CuSCN layer have been visualized using scanning electron microscopy (SEM). The cells were fabricated with the configuration of FTO/ ZnO dense layer/ ZnO porous layer/D149/CuSCN/Graphite/Cr-coated FTO. Then the cells were characterized using I-V data as functions of the dense layer resistance (which is proportional to the thickness of the dense layer) and the porous layer thicknesses. The optimum dense layer is found to have 1500 Ω/□ sheet resistance. The cell with porous layer thickness of 9 μm at this dense layer resistance shows the maximum power conversion efficiency of 2.28%. The solar cell parameters of this optimized cell are an open circuit voltage of 0.55 V, a fill factor of 0.51 and a short-circuit current density of 8.2 mA cm-2.
DAMPING ANALYSIS WITH RESPECT TO ROLLING SPEED BY ANALYTIC SOLUTION OF A FLEXIBLE RING MODEL AND ITS FREQUENCY RESPONSE FUNCTION DERIVATION BY MODAL SUMMATION METHOD
Authors: LEE JONGSUH , WANG SEMYUNG , KINDT PETER , PLUYMERS BERT , DESMET WIM
Published: September 2014

In this research, a modal approach has been adopted to analyze the dynamic characteristics of the rolling tire by a ring model. Previously, most of the researchers focused on the changes in natural frequencies with respect to the rotational speed (in global coordinate) only. In this research, the change in the damping has also been taken into account by including a damping term in the ring model equations. The bi-orthogonal property which is used to obtain the Frequency Response Functions (FRFs) of a rotor/bearing system described in Cartesian coordinate has been applied to the ring model described in cylindrical coordinate to obtain the FRFs. The obtained damping values and FRFs from the analytic model are then compared with experimental results. Moreover, the physical meanings of the results are analyzed, based on experimental data of a stationary tire and a rolling tire at 60 km/h and 100 km/h.
Gold Nanoparticle Arrays Spectroscopy: Observation of Electrostatic and Radiative Dipole Interactions
Authors: Marhaba Salem
Published: September 2014

In this paper, localized surface plasmon resonance (LSPR) of periodic two-dimensional (2D) gold nanoparticles arrays is investigated using far field polarization spectroscopy. Square and rectangular arrays of 60 nm gold nanoparticles with different interparticle spacings are fabricated with electron beam lithography (EBL). The experimental extinction cross section spectra are revealed the existence of two plasmon modes depending to the polarization direction of the incident radiation on the sample. The extinction spectra are calculated using coupled dipole approximation (CDA). Good qualitative and quantitative agreement is obtained between calculations and experimental results. Moreover, it is found that the interparticle spacing on the array was the key parameter to study the plasmon interaction between the nanoparticles and to determine the amplitude, spectral position and width of LSPR band.
On the solutions and periodic nature of some systems of difference equations
Authors: Elsayed E. M.
Published: September 2014

In this paper, we consider the solution of the following rational systems of difference equations: [Formula: see text] where initial conditions are nonzero real numbers.
Nanoporous WO3–Fe2O3 films; structural and photo-electrochemical characterization
Authors: Solarska Renata , Bieńkowski Krzysztof , Królikowska Agata , Dolata Mirosław , Augustyński Jan
Published: September 2014

We investigated the structure and photo-electrochemical properties for water splitting of tungsten trioxide-ferric oxide thin films formed by spray pyrolysis. While annealing at 600°C produces films consisting of a mixture of monoclinic WO 3 and hematite α- Fe 2 O 3, the heating at a temperature above 1000°C affords formation of ferric tungstate Fe 2 WO 6. Both kinds of films exhibit optical absorption range comparable or exceeding that of α- Fe 2 O 3. Another important feature is a decreased rate of charge recombination of the mixed-oxide Fe 2 O 3- WO 3 with respect to the ferric oxide photo-anodes.
Modeling and computation of the cavitating flow in injection nozzle holes
Authors: Kanfoudi Hatem , Zgolli Ridha
Published: September 2014

Cavitating flows inside a diesel injection nozzle hole were simulated using a mixture model. A two-dimensional (2D) numerical model is proposed in this paper to simulate steady cavitating flows. The Reynolds-averaged Navier–Stokes equations are solved for the liquid and vapor mixture, which is considered as a single fluid with variable density and expressed as a function of the vapor volume fraction. The closure of this variable is provided by the transport equation with a source term Transport-equation based methods (TEM). The processes of evaporation and condensation are governed by changes in pressure within the flow. The source term is implanted in the CFD code ANSYS CFX. The influence of numerical and physical parameters is presented in detail. The numerical simulations are in good agreement with the experimental data for steady flow.
NMR SPECTROSCOPY ON HEUSLER THIN FILMS — A REVIEW
Authors: WURMEHL SABINE , KOHLHEPP JÜRGEN T.
Published: September 2014

Heusler compounds exhibit different electronic ground states and functionalities, making them attractive materials for studies of their fundamental properties and for their technological exploitation. The high spin polarization, predicted in particular for Co 2-based Heusler compounds, renders them prime candidates for electrode materials in spintronic devices such as giant magnetoresistance (GMR) elements or magnetic tunnel junctions and requires their implementation in thin film stacks. The growth of high quality Heusler films, however, demands their careful characterization. Typical issues in Heusler thin films are, besides the type and degree of structural order, the control of the film composition and the conservation of smooth interfaces between different layers in the film, e.g., between the Heusler layer and the tunneling barrier, while at the same time enabling high structural order. This review illustrates how nuclear magnetic resonance spectroscopy contributes to those issues by discussing recent examples of nuclear magnetic resonance studies of Heusler thin films.
Static and dynamic properties of argon inside carbon nanotubes
Authors: Ye Hong-Fei , Zhang Zhong-Qiang , Zheng Yong-Gang , Zhang Hong-Wu , Chen Zhen , Zong Zhi
Published: September 2014

By using the molecular dynamics simulations, the static and dynamic properties of the argon inside the (10, 10), (20, 20) and (40, 40) carbon nanotubes (CNTs) are investigated. Here, the temperatures of 90 K and 298 K are considered to examine the temperature dependence of the concerned properties of the confined argon. The simulation results reveal that there are two clear atomic layers inside the (10, 10) CNTs at the two temperatures. As the diameter of the CNTs increases, the atomic layers become detectable only in the boundary region with the increase in temperature. For the dynamic property, the motion of the argon along the axial direction follows the conventional Fickian diffusion in the most cases, which is very slow in the case of close packing. In the radial direction, the subdiffusion and the Fickian diffusion can only be observed in the initial stage and then the mean squared displacements gradually approach the saturated values. The diffusion coefficients of the confined argon have a consistent tendency with those of the bulk argon after considering the actual reduced density.
The Genetics of Skeletal Muscle Disorders in Horses
Authors: Mickelson James R. , Valberg Stephanie J.
Published: September 2014

Horses are remarkable athletes and a fascinating species in which to study the genetic bases of athletic performance, skeletal muscle biology, and neuromuscular disease. Genetic selection in horses has resulted in many breeds that possess anatomical, physiological, and metabolic variations linked to speed, power, and endurance that are beginning to be defined at the molecular level. Along with the concentration of positive traits, equine breeding programs have also inadvertently concentrated heritable muscle diseases for which mutations impacting electrical conduction, muscle contraction, and energy metabolism within and across breeds have been characterized. The study of heritable muscle diseases in horses has provided exciting insights into the normal structure and function of muscle and important diagnostic tools for veterinarians. Results empower breeders and breed associations to make difficult decisions about how to use this information to improve the overall health and well-being of horses.
The Domestic Piglet: An Important Model for Investigating the Neurodevelopmental Consequences of Early Life Insults
Authors: Conrad Matthew S. , Johnson Rodney W.
Published: September 2014

Insults in the prenatal and early postnatal period increase the risk for behavioral problems later in life. One hypothesis is that pre- and postnatal stressors influence structural and functional brain plasticity. Understanding the mechanisms is important, but progress has lagged because certain studies in human infants are impossible, while others are extremely difficult. Furthermore, results from popular rodent models are difficult to translate to human infants owing to the substantial differences in brain development and morphology. Because it overcomes some of these obstacles, the domestic piglet has emerged as an important model. Piglets have a gyrencephalic brain that develops similar to the human brain and that can be assessed in vivo by using clinical-grade neuroimaging instruments. Furthermore, owing to their precocial nature, piglets can be weaned at birth and used in behavioral testing paradigms to assess cognitive behavior at an early age. Thus, the domestic piglet represents an important translational model for investigating the neurodevelopmental consequences of early life insults.
Citizen Science: A Tool for Integrating Studies of Human and Natural Systems
Authors: Crain Rhiannon , Cooper Caren , Dickinson Janis L.
Published: September 2014

Citizen science has proliferated in the last decade, becoming a critical form of public engagement in science and an increasingly important research tool for the study of large-scale patterns in nature. Although citizen science is already interdisciplinary, it has untapped potential to build capacity for transformative research on coupled human and natural systems. New tools have begun to collect paired ecological and social data from the same individual; this allows for detailed examination of feedbacks at the level of individuals and potentially provides much-needed data for agent-based modeling. With the ongoing professionalization of citizen science, the field can benefit from integrating a coupled systems perspective, including a broadening of the social science perspectives considered. This can lead to new schema and platforms to increase support for large-scale research on coupled natural and human systems.
Blockholders and Corporate Governance
Authors: Edmans Alex
Published: September 2014

This paper reviews the theoretical and empirical literature on the channels through which blockholders (large shareholders) engage in corporate governance. In classical models, blockholders exert governance through direct intervention in a firm’s operations, otherwise known as “voice.” These theories have motivated empirical research on the determinants and consequences of activism. More recent models show that blockholders can govern through an alternative mechanism known as “exit”—selling their shares if the manager underperforms. These theories give rise to new empirical studies on the two-way relationship between blockholders and financial markets, linking corporate finance with asset pricing. Blockholders may also worsen governance by extracting private benefits of control or pursuing objectives other than firm value maximization. I highlight the empirical challenges in identifying causal effects of and on blockholders as well as the typical strategies attempted to achieve identification. I close with directions for future research.
Ignition, Liftoff, and Extinction of Gaseous Diffusion Flames
Authors: Liñán Amable , Vera Marcos , Sánchez Antonio L.
Published: September 2014

This review uses as a vehicular example the jet-flame configuration to examine some phenomena that emerge in nonpremixed gaseous combustion as a result of the interaction between the temperature-sensitive chemical reaction, typical of combustion, and the convective and diffusive transport. These include diffusion-controlled flames, edge flames and their role in flame attachment, triple flames and their role as ignition fronts, and strain-induced extinction, including flame-vortex interactions. The aim is to give an overall view of the fluid dynamics of nonpremixed combustion and to review the most relevant contributions.
The Genetics of Neisseria Species
Authors: Rotman Ella , Seifert H. Steven
Published: September 2014

Neisseria gonorrhoeae and Neisseria meningitidis are closely related organisms that cause the sexually transmitted infection gonorrhea and serious bacterial meningitis and septicemia, respectively. Both species possess multiple mechanisms to alter the expression of surface-exposed proteins through the processes of phase and antigenic variation. This potential for wide variability in surface-exposed structures allows the organisms to always have subpopulations of divergent antigenic types to avoid immune surveillance and to contribute to functional variation. Additionally, the Neisseria are naturally competent for DNA transformation, which is their main means of genetic exchange. Although bacteriophages and plasmids are present in this genus, they are not as effective as DNA transformation for horizontal genetic exchange. There are barriers to genetic transfer, such as restriction-modification systems and CRISPR loci, that limit particular types of exchange. These host-restricted pathogens illustrate the rich complexity of genetics that can help define the similarities and differences of closely related organisms.
The Relations Between Recombination Rate and Patterns of Molecular Variation and Evolution inDrosophila
Authors: Charlesworth Brian , Campos José L.
Published: September 2014

Genetic recombination affects levels of variability and the efficacy of selection because natural selection acting at one site affects evolutionary processes at linked sites. The variation in local recombination rates across the Drosophila genome provides excellent material for testing hypotheses concerning the evolutionary consequences of recombination. The current state of knowledge from studies of Drosophila genomics and population genetics is reviewed here. Selection at linked sites has influenced the relations between recombination rates and patterns of molecular variation and evolution, such that higher rates of recombination are associated with both higher levels of variability and a greater efficacy of selection. It seems likely that background selection against deleterious mutations is a major factor contributing to these patterns in genome regions in which crossing over is rare or absent, whereas selective sweeps of positively selected mutations probably play an important role in regions with crossing over.
Subsurface Chlorophyll Maximum Layers: Enduring Enigma or Mystery Solved?
Authors: Cullen John J.
Published: September 2014

The phenomenon of subsurface chlorophyll maximum layers (SCMLs) is not a unique ecological response to environmental conditions; rather, a broad range of interacting processes can contribute to the formation of persistent layers of elevated chlorophyll a concentration (Chl) that are nearly ubiquitous in stratified surface waters. Mechanisms that contribute to the formation and maintenance of the SCMLs include a local maximum in phytoplankton growth rate near the nutricline, photoacclimation of pigment content that leads to elevated Chl relative to phytoplankton biomass at depth, and a range of physiologically influenced swimming behaviors in motile phytoplankton and buoyancy control in diatoms and cyanobacteria that can lead to aggregations of phytoplankton in layers, subject to grazing and physical control. A postulated typical stable water structure characterizes consistent patterns in vertical profiles of Chl, phytoplankton biomass, nutrients, and light across a trophic gradient structured by the vertical flux of nutrients and characterized by the average daily irradiance at the nutricline. Hypothetical predictions can be tested using a nascent biogeochemical global ocean observing system. Partial results to date are generally consistent with predictions based on current knowledge, which has strong roots in research from the twentieth century.
There and Back Again: A Review of Residency and Return Migrations in Sharks, with Implications for Population Structure and Management
Authors: Chapman Demian D. , Feldheim Kevin A. , Papastamatiou Yannis P. , Hueter Robert E.
Published: September 2014

The overexploitation of sharks has become a global environmental issue in need of a comprehensive and multifaceted management response. Tracking studies are beginning to elucidate how shark movements shape the internal dynamics and structure of populations, which determine the most appropriate scale of these management efforts. Tracked sharks frequently either remain in a restricted geographic area for an extended period of time (residency) or return to a previously resided-in area after making long-distance movements (site fidelity). Genetic studies have shown that some individuals of certain species preferentially return to their exact birthplaces (natal philopatry) or birth regions (regional philopatry) for either parturition or mating, even though they make long-distance movements that would allow them to breed elsewhere. More than 80 peer-reviewed articles, constituting the majority of published shark tracking and population genetic studies, provide evidence of at least one of these behaviors in a combined 31 shark species from six of the eight extant orders. Residency, site fidelity, and philopatry can alone or in combination structure many coastal shark populations on finer geographic scales than expected based on their potential for dispersal. This information should therefore be used to scale and inform assessment, management, and conservation activities intended to restore depleted shark populations.
Therapeutic Modulation of Urinary Bladder Function: Multiple Targets at Multiple Levels
Authors: Michel Martin C.
Published: September 2014

Storage dysfunction of the urinary bladder, specifically overactive bladder syndrome, is a condition that occurs frequently in the general population. Historically, pathophysiological and treatment concepts related to overactive bladder have focused on smooth muscle cells. Although these are the central effector, numerous anatomic structures are involved in their regulation, including the urothelium, afferent and efferent nerves, and the central nervous system. Each of these structures involves receptors for—and the urothelium itself also releases—many mediators. Moreover, hypoperfusion, hypertrophy, and fibrosis can affect bladder function. Established treatments such as muscarinic antagonists, β-adrenoceptor agonists, and onabotulinumtoxinA each work in part through their effects on the urothelium and afferent nerves, as do α1-adrenoceptor antagonists in the treatment of voiding dysfunction associated with benign prostatic hyperplasia; however, none of these treatments are specifically targeted to the urothelium and afferent nerves. It remains to be explored whether future treatments that specifically act at one of these structures will provide a therapeutic advantage.
Social Pain and the Brain: Controversies, Questions, and Where to Go from Here
Authors: Eisenberger Naomi I.
Published: September 2014

Emerging evidence has shown that social pain—the painful feelings that follow from social rejection, exclusion, or loss—relies on some of the same neural regions that process physical pain, highlighting a possible physical-social pain overlap. However, the hypothesis that physical pain and social pain rely on shared neural systems has been contested. This review begins by summarizing research supporting the physical-social pain overlap. Next, three criticisms of this overlap model are presented and addressed by synthesizing available research. These criticisms include the suggestions that (a) neural responses to social pain are indicative of conflict detection processes, rather than distress; (b) all negative affective processes, rather than social pain specifically, activate these pain-related neural regions; and (c) neural responses to social (and physical) pain reflect the processing of salience, rather than hurt. Implications of these findings for understanding social and physical pain are discussed, and key next steps are suggested.
Perceptual Learning: Toward a Comprehensive Theory
Authors: Watanabe Takeo , Sasaki Yuka
Published: September 2014

Visual perceptual learning (VPL) is long-term performance increase resulting from visual perceptual experience. Task-relevant VPL of a feature results from training of a task on the feature relevant to the task. Task-irrelevant VPL arises as a result of exposure to the feature irrelevant to the trained task. At least two serious problems exist. First, there is the controversy over which stage of information processing is changed in association with task-relevant VPL. Second, no model has ever explained both task-relevant and task-irrelevant VPL. Here we propose a dual plasticity model in which feature-based plasticity is a change in a representation of the learned feature, and task-based plasticity is a change in processing of the trained task. Although the two types of plasticity underlie task-relevant VPL, only feature-based plasticity underlies task-irrelevant VPL. This model provides a new comprehensive framework in which apparently contradictory results could be explained.