bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature dependent dynamics transition of intermittent plastic flow in a metallic glass. II. Dynamics analysis
Authors: Liu Z. Y. , Wang G. , Chan K. C. , Ren J. L. , Huang Y. J. , Bian X. L. , Xu X. H. , Zhang D. S. , Gao Y. L. , Zhai Q. J.
Published: July 2013

By reducing the testing temperatures down to the temperature well below the glassy transition temperature, the serrated flow behaviour during plastic deformation of a Zr-based metallic glass was experimentally investigated and the results were presented in Part I of the present paper. It shows that the yield strength, the plastic deformation ability, the density of shear bands of the metallic glass increase with decreasing temperature. In order to understand the mechanisms for the changes of the mechanical behaviour at low temperatures, in Part II of this study, the stress-time sequence in the plastic strain regime is characterized by a comprehensive dynamical and statistical analysis. The stress-time sequence is found to exhibit a chaotic state at high temperatures (>203 K), whereas a self-organized critical state is obtained at low temperatures (≤203 K) due to the freezing effect. The reasons for the transition between these two distinct spatio-temporal dynamical states are elucidated by investigating the effect of temperature on the deformation units (shear transformation zones) and the elastic interactions between neighbouring shear bands. The results demonstrate that the low temperatures results in an enhancement of the interactions between the elastic strain fields initiated by neighbouring shear bands, which is primarily responsible for the enhanced plasticity of the metallic glass and a dynamics transition.
Three-dimensional extreme ultraviolet emission from a droplet-based laser-produced plasma
Authors: Giovannini A. Z. , Abhari Reza S.
Published: July 2013

The emission of extreme ultraviolet radiation in a 2% bandwidth centered at 13.5 nm (in-band) is measured in one hemisphere. The targets of the laser are tin droplets. In-band emission is measured at angles from the laser axis larger than 120°. Analytical models representing the physical processes are developed and calibrated with the experimental data. In the models two assumptions are investigated, isentropic and isothermal 2D-axisymmetric expansion. The parameters of the models are the density distribution of the plasma and the location where the EUV emission is centered. The parameters are inferred by the calibration of the models with the experimental data. The predictions of the models are validated with experiments where slab targets were used.
Carbon nanotube resonators with capacitive and piezoresistive current modulation readout
Authors: Lee Shih-Wei , Truax Stuart , Yu Liu , Roman Cosmin , Hierold Christofer
Published: July 2013

In this work, a single-walled carbon nanotube (SWCNT) nanomechanical resonator is characterized at mechanical resonance using both capacitive modulation and piezoresistive modulation effects. The piezoresistive modulation effect is shown to be a robust method for measuring the resonant response, allowing improved detection of the SWCNT resonance by reducing the off-resonance drain current by a factor of up to 10. Equivalent circuit parameters describing the piezoelectric effect are extracted. The measured device shows a Q-factor of 91 and a piezoresistive bandgap bending of 0.04 eV/% strain for a resonance at 79.5 MHz. The SWCNT is measured at 300 K and 7 × 10−4 Pa.
The density of states of graphene underneath a metal electrode and its correlation with the contact resistivity
Authors: Ifuku Ryota , Nagashio Kosuke , Nishimura Tomonori , Toriumi Akira
Published: July 2013

The density of states (DOS) of graphene underneath a metal is estimated through a quantum capacitance measurement of the metal/graphene/SiO2/n+-Si contact structure fabricated by a resist-free metal deposition process. Graphene underneath Au maintains a linear DOS–energy relationship except near the Dirac point, whereas the DOS of graphene underneath Ni is broken and largely enhanced around the Dirac point, resulting in only a slight modulation of the Fermi energy. Moreover, the DOS of graphene in the contact structure is correlated with the contact resistivity measured using devices fabricated by the resist-free process.
Adiabatic fiber microtaper with incorporated an air-gap microcavity fiber Fabry-Pérot interferometer
Authors: Lee Cheng-Ling , Tai Ching-Yi , Chen Chien-Lin , Han Pin
Published: July 2013

This study demonstrates an adiabatic fiber microtaper with incorporated an air-gap microcavity fiber-Fabry-Pérot-interferometer to perform superior sensing characteristics. Optical interference fringes with good fringes contrast within bandwidth of 1250–1650 nm are performed experimentally. A highly spectral sensitivity of peak power with +3.65 dB/ °C (+9759 dB/RIU) is achieved when the device is operated under a fundamental-mode-cutoff (FMC) condition. By measuring peak power of the fringe, one can determine the temperature (T) or refractive index of environment. The proposed hybrid sensor is further applied to measure high T (∼1000 °C) of surrounding in non-FMC condition that obtains a good linearity of spectral response.
Efficient proton acceleration and focusing by an ultraintense laser interacting with a parabolic double concave target with an extended rear
Authors: Bake Muhammad Ali , Xie Bai-Song , Aimidula Aimierding , Wang Hong-Yu
Published: July 2013

A new scheme for acceleration and focusing of protons via an improved parabolic double concave target irradiated by an ultraintense laser pulse is proposed. When an intense laser pulse illuminates a concave target, the hot electrons are concentrated on the focal region of the rear cavity and they form a strong space-charge-separation field, which accelerates the protons. For a simple concave target, the proton energy spectrum becomes very broad outside the rear cavity because of transverse divergence of the electromagnetic fields. However, particle-in-cell simulations show that, when the concave target has an extended rear, the hot electrons along the wall surface induce a transverse focusing sheath field, resulting in a clear enhancement of proton focusing, which makes the lower proton energy spread, while, leads to a little reduction of the proton bunch peak energy.
130-fold enhancement of TiO2 photocatalytic activities by ball milling
Authors: Saitow Ken-ichi , Wakamiya Tomoji
Published: July 2013

Submicrometer TiO2 particles were prepared by changing the mechanochemical parameters in planetary ball milling. The TiO2 particles before and after milling were characterized by five experimental methods. The photocatalytic activities of the TiO2 particles were evaluated by the photoreduction of an aqueous solution of methylene blue. The activity of milled TiO2 was 136 times that of TiO2 (anatase) before milling and 62 times that of commercial available TiO2 photocatalyst (P25). In addition to the reduction in particle size and increase in specific surface area due to milling, the disorder TiO2, involving amorphous and srilankite phases, significantly increased the catalytic performance.
Effects of surface properties on barrier height and barrier inhomogeneities of platinum contacts to n-type 4H-SiC
Authors: Huang Lingqin , Qin Fuwen , Li Shijuan , Wang Dejun
Published: July 2013

We investigated the Schottky barrier of Pt/4H-SiC contact as a function of 4H-SiC surface properties which effectively controlled by electronic cyclotron resonance hydrogen plasma pretreatment for different periods and annealing. It is found that the effective barrier height monotonically increases with decreasing the degree of Fermi level pinning. Electrically homogeneous contacts are observed when the Fermi level (FL) is “pinned (Bardeen limit)” and “free-pinned (Schottky limit).” However, a partial pinning of FL leads to Gaussian distribution of inhomogeneous barrier height. These results could be correlated with changes in the magnitude and spatial distribution of surface state density after different pretreatments.
Optimal width of quantum well for reversed polarization blue InGaN light-emitting diodes
Authors: Kang Junjie , Li Zhi , Li Hongjian , Liu Zhiqiang , Ma Ping , Yi Xiaoyan , Wang Guohong
Published: July 2013

The optical properties of reversed polarization (RP) blue InGaN light-emitting diodes (LEDs) under different quantum wells (QWs) width are numerically studied. We compared the band diagram, electron and hole concentration, emission wavelength, radiation recombination, internal quantum efficiency (IQE), turn on voltage and light output power (LOP) of these structures by numerical simulation. It found that QW width has a remarkable influence on the properties of RP blue InGaN LEDs. With the increase of QW width, the turn on voltage and radiation recombination rate decreases. It finds that the optimal width of QWs is about 3 nm at the current injection density of 15 A/cm2.
Development and Design of a Web-Based Interface to Address Geographical Incompatibility in Spatial Units
Authors: Walford Nigel
Published: July 2013

The issue of how to address geographical incompatibility between aggregate statistical data sources is one affecting researchers in many countries. The increased amount of data from recent British Population Censuses has been accompanied by considerable changes in both administrative and electoral boundaries as well as those of areas specifically defined for census data collection and statistical output purposes. This paper reviews the extent of geographical inconsistency at different spatial scales and outlines the development of a web-based interface that implements an intelligent areal interpolation (dasymetric mapping) algorithm that enables estimates of census counts to be obtained for consistent spatial units across pairs of recent British censuses (1981, 1991, and 2001). A limited-access user trial has been carried out and the paper illustrates a typical user query that seeks to estimate 1981 population counts in 1991 enumeration district boundaries. The paper concludes by considering further development of the interface, its incorporation into the services provided by existing census data units in the UK, and its wider potential for addressing the issues of geographical incompatibility.
Molecular Characterization of Collagen Hydroxylysine O-Glycosylation by Mass Spectrometry: Current Status
Authors: Perdivara Irina , Yamauchi Mitsuo , Tomer Kenneth B.
Published: July 2013

The most abundant proteins in vertebrates – the collagen family proteins – play structural and biological roles in the body. The predominant member, type I collagen, provides tissues and organs with structure and connectivity. This protein has several unique post-translational modifications that take place intra- and extra-cellularly. With growing evidence of the relevance of such post-translational modifications in health and disease, the biological significance of O-linked collagen glycosylation has recently drawn increased attention. However, several aspects of this unique modification – the requirement for prior lysyl hydroxylation as a substrate, involvement of at least two distinct glycosyl transferases, its involvement in intermolecular crosslinking – have made its molecular mapping and quantitative characterization challenging. Such characterization is obviously crucial for understanding its biological significance. Recent progress in mass spectrometry has provided an unprecedented opportunity for this type of analysis. This review summarizes recent advances in the area of O-glycosylation of fibrillar collagens and their characterization using state-of-the-art liquid chromatography–mass spectrometry-based methodologies, and perspectives on future research. The analytical characterization of collagen crosslinking and advanced glycation end-products are not addressed here.
2×2 Dominant achievement goal profiles in high‐level swimmers
Authors: Fernandez‐Rio Javier , Cecchini Estrada Jose A. , Mendez‐Giménez Antonio , Fernández‐Garcia Benjamín , Saavedra Pablo
Published: July 2013

The goal of this study was to assess achievement goal dominance, self‐determined situational motivation and competence in high‐level swimmers before and after three training sessions set at different working intensities (medium, sub‐maximal and maximal). Nineteen athletes (males, n=9, 18.00±2.32 years; females, n=10, 16.30±2.01 years, range = 14–18) agreed to participate. They completed a questionnaire that included the Dominant Achievement Goal assessment instrument, the 2×2 Achievement Goals Questionnaire for Sport (AGQ‐S), The Situational Motivation Scale (SIMS) and the Competence subscale of the Basic Psychological Needs in Exercise questionnaire (BPNES). Results indicated that participants overwhelmingly showed mastery‐approach achievement goal dominance, and it remained stable at the conclusion of the different training sessions under all intensity levels. This profile was positively correlated to self‐determined situational motivation and competence. However, swimmers' feelings of competence increased only after the medium intensity level training session. After the completion of the maximal intensity training session, swimmers' self‐determined motivation was significantly lower compared to the other two training sessions, which could be caused by a temporary period of burnout. Results indicated that high‐level swimmers had a distinct mastery‐approach dominant achievement goal profile that was not affected by the workload of the different training sessions. They also showed high levels of self‐determined situational motivation and competence. However, heavy workloads should be controlled because they can cause transitory burnout.
Superoxide radicals have a protective role during H2O2stress
Authors: Thorpe Geoffrey W. , Reodica Mayfebelle , Davies Michael J. , Heeren Gino , Jarolim Stefanie , Pillay Bethany , Breitenbach Michael , Higgins Vincent J. , Dawes Ian W.
Published: July 2013

Reactive oxygen species (ROS) consist of potentially toxic, partly reduced oxygen species and free radicals. After H2O2treatment, yeast cells significantly increase superoxide radical production. Respiratory chain complex III and possibly cytochrome b function are essential for this increase. Disruption of complex III renders cells sensitive to H2O2but not to the superoxide radical generator menadione. Of interest, the same H2O2-sensitive mutant strains have the lowest superoxide radical levels, and strains with the highest resistance to H2O2have the highest levels of superoxide radicals. Consistent with this correlation, overexpression of superoxide dismutase increases sensitivity to H2O2, and this phenotype is partially rescued by addition of small concentrations of menadione. Small increases in levels of mitochondrially produced superoxide radicals have a protective effect during H2O2-induced stress, and in response to H2O2, the wild-type strain increases superoxide radical production to activate this defense mechanism. This provides a direct link between complex III as the main source of ROS and its role in defense against ROS. High levels of the superoxide radical are still toxic. These opposing, concentration-dependent roles of the superoxide radical comprise a form of hormesis and show one ROS having a hormetic effect on the toxicity of another.
UDP-glucose:glycoprotein glucosyltransferase (UGGT1) promotes substrate solubility in the endoplasmic reticulum
Authors: Ferris Sean P. , Jaber Nikita S. , Molinari Maurizio , Arvan Peter , Kaufman Randal J.
Published: July 2013

Protein folding in the endoplasmic reticulum (ER) is error prone, and ER quality control (ERQC) processes ensure that only correctly folded proteins are exported from the ER. Glycoproteins can be retained in the ER by ERQC, and this retention contributes to multiple human diseases, termed ER storage diseases. UDP-glucose:glycoprotein glucosyltransferase (UGGT1) acts as a central component of glycoprotein ERQC, monoglucosylating deglucosylated N-glycans of incompletely folded glycoproteins and promoting subsequent reassociation with the lectin-like chaperones calreticulin and calnexin. The extent to which UGGT1 influences glycoprotein folding, however, has only been investigated for a few selected substrates. Using mouse embryonic fibroblasts lacking UGGT1 or those with UGGT1 complementation, we investigated the effect of monoglucosylation on the soluble/insoluble distribution of two misfolded α1-antitrypsin (AAT) variants responsible for AAT deficiency disease: null Hong Kong (NHK) and Z allele. Whereas substrate solubility increases directly with the number of N-linked glycosylation sites, our results indicate that additional solubility is conferred by UGGT1 enzymatic activity. Monoglucosylation-dependent solubility decreases both BiP association with NHK and unfolded protein response activation, and the solubility increase is blocked in cells deficient for calreticulin. These results suggest that UGGT1-dependent monoglucosylation of N-linked glycoproteins promotes substrate solubility in the ER.
deltaGseg: macrostate estimation via molecular dynamics simulations and multiscale time series analysis
Authors: Low Diana H. P. , Motakis Efthymios
Published: July 2013

Summary: Binding free energy calculations obtained through molecular dynamics simulations reflect intermolecular interaction states through a series of independent snapshots. Typically, the free energies of multiple simulated series (each with slightly different starting conditions) need to be estimated. Previous approaches carry out this task by moving averages at certain decorrelation times, assuming that the system comes from a single conformation description of binding events. Here, we discuss a more general approach that uses statistical modeling, wavelets denoising and hierarchical clustering to estimate the significance of multiple statistically distinct subpopulations, reflecting potential macrostates of the system. We present the deltaGseg R package that performs macrostate estimation from multiple replicated series and allows molecular biologists/chemists to gain physical insight into the molecular details that are not easily accessible by experimental techniques.

Availability:  deltaGseg is a Bioconductor R package available at http://bioconductor.org/packages/release/bioc/html/deltaGseg.html.

Contact:  emotakis@hotmail.com
Neuroprotection against Traumatic Brain Injury by Xenon, but Not Argon, Is Mediated by Inhibition at the N-Methyl-d-Aspartate Receptor Glycine Site
Authors: Harris Katie , Armstrong Scott P. , Campos-Pires Rita , Kiru Louise , Franks Nicholas P. , Dickinson Robert
Published: July 2013

Background:

Xenon, the inert anesthetic gas, is neuroprotective in models of brain injury. The authors investigate the neuroprotective mechanisms of the inert gases such as xenon, argon, krypton, neon, and helium in an in vitro model of traumatic brain injury.

Methods:

The authors use an in vitro model using mouse organotypic hippocampal brain slices, subjected to a focal mechanical trauma, with injury quantified by propidium iodide fluorescence. Patch clamp electrophysiology is used to investigate the effect of the inert gases on N-methyl-d-aspartate receptors and TREK-1 channels, two molecular targets likely to play a role in neuroprotection.

Results:

Xenon (50%) and, to a lesser extent, argon (50%) are neuroprotective against traumatic injury when applied after injury (xenon 43 ± 1% protection at 72 h after injury [N = 104]; argon 30 ± 6% protection [N = 44]; mean ± SEM). Helium, neon, and krypton are devoid of neuroprotective effect. Xenon (50%) prevents development of secondary injury up to 48 h after trauma. Argon (50%) attenuates secondary injury, but is less effective than xenon (xenon 50 ± 5% reduction in secondary injury at 72 h after injury [N = 104]; argon 34 ± 8% reduction [N = 44]; mean ± SEM). Glycine reverses the neuroprotective effect of xenon, but not argon, consistent with competitive inhibition at the N-methyl-d-aspartate receptor glycine site mediating xenon neuroprotection against traumatic brain injury. Xenon inhibits N-methyl-d-aspartate receptors and activates TREK-1 channels, whereas argon, krypton, neon, and helium have no effect on these ion channels.

Conclusions:

Xenon neuroprotection against traumatic brain injury can be reversed by increasing the glycine concentration, consistent with inhibition at the N-methyl-d-aspartate receptor glycine site playing a significant role in xenon neuroprotection. Argon and xenon do not act via the same mechanism.
Honeybee combs: how the circular cells transform into rounded hexagons
Authors: Karihaloo B. L. , Zhang K. , Wang J.
Published: July 2013

We report that the cells in a natural honeybee comb have a circular shape at ‘birth’ but quickly transform into the familiar rounded hexagonal shape, while the comb is being built. The mechanism for this transformation is the flow of molten visco-elastic wax near the triple junction between the neighbouring circular cells. The flow may be unconstrained or constrained by the unmolten wax away from the junction. The heat for melting the wax is provided by the ‘hot’ worker bees.
Applicability of ToF-SIMS for monitoring compositional changes in bone in a long-term animal model
Authors: Henss Anja , Rohnke Marcus , El Khassawna Thaqif , Govindarajan Parameswari , Schlewitz Gudrun , Heiss Christian , Janek Juergen
Published: July 2013

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a well-established technique in material sciences but has not yet been widely explored for implementation in life sciences. Here, we demonstrate the applicability and advantages of ToF-SIMS analysis for the study of minerals and biomolecules in osseous tissue. The locally resolved analysis of fragment ions deriving from the sample surface enables imaging and differentiation of bone tissue and facilitates histology on non-stained cross sections. In a rat model, bilateral ovariectomy combined with either a multi-deficiency diet or steroid treatment was carried out to create osteoporotic conditions. We focused our study on the Ca content of the mineralized tissue and monitored its decline. Calcium mass images of cross sections show the progressive degenerative changes in the bone. We observed a decreased Ca concentration in the edge region of the trabeculae and a decline in the Ca/P ratio. Additionally, we focused on the non-mineralized matrix and identified fragment ions that are characteristic for the collagen matrix. We observed trabeculae with wide ranges of non-mineralized collagen for the diet group owing to an impaired mineralization process. Here, the advantage of coeval monitoring of collagen and minerals indicated an osteomalacic model rather than an osteoporotic one.
Structuring targeted surveillance for monitoring disease emergence by mapping observational data onto ecological process
Authors: Gerardo-Giorda Luca , Puggioni Gavino , Rudd Robert J. , Waller Lance A. , Real Leslie A.
Published: July 2013

An efficient surveillance system is a crucial factor in identifying, monitoring and tackling outbreaks of infectious diseases. Scarcity of data and limited amounts of economic resources require a targeted effort from public health authorities. In this paper, we propose a mathematical method to identify areas where surveillance is critical and low reporting rates might leave epidemics undetected. Our approach combines the use of reference-based susceptible–exposed–infectious models and observed reporting data; We propose two different specifications, for constant and time-varying surveillance, respectively. Our case study is centred around the spread of the raccoon rabies epidemic in the state of New York, using data collected between 1990 and 2007. Both methods offer a feasible solution to analyse and identify areas of intervention.
Enlarging Cells Initiating Apomixis inHieracium praealtumTransition to an Embryo Sac Program prior to Entering Mitosis
Authors: Okada Takashi , Hu Yingkao , Tucker Matthew R. , Taylor Jennifer M. , Johnson Susan D. , Spriggs Andrew , Tsuchiya Tohru , Oelkers Karsten , Rodrigues Julio C.M. , Koltunow Anna M.G.
Published: July 2013

Hieracium praealtum forms seeds asexually by apomixis. During ovule development, sexual reproduction initiates with megaspore mother cell entry into meiosis and formation of a tetrad of haploid megaspores. The sexual pathway ceases when a diploid aposporous initial (AI) cell differentiates, enlarges, and undergoes mitosis, forming an aposporous embryo sac that displaces sexual structures. Embryo and endosperm development in aposporous embryo sacs is fertilization independent. Transcriptional data relating to apomixis initiation in Hieracium spp. ovules is scarce and the functional identity of the AI cell relative to other ovule cell types is unclear. Enlarging AI cells with undivided nuclei, early aposporous embryo sacs containing two to four nuclei, and random groups of sporophytic ovule cells not undergoing these events were collected by laser capture microdissection. Isolated amplified messenger RNA samples were sequenced using the 454 pyrosequencing platform and comparatively analyzed to establish indicative roles of the captured cell types. Transcriptome and protein motif analyses showed that approximately one-half of the assembled contigs identified homologous sequences in Arabidopsis (Arabidopsis thaliana), of which the vast majority were expressed during early Arabidopsis ovule development. The sporophytic ovule cells were enriched in signaling functions. Gene expression indicative of meiosis was notably absent in enlarging AI cells, consistent with subsequent aposporous embryo sac formation without meiosis. The AI cell transcriptome was most similar to the early aposporous embryo sac transcriptome when comparing known functional annotations and both shared expressed genes involved in gametophyte development, suggesting that the enlarging AI cell is already transitioning to an embryo sac program prior to mitotic division.
Solid Lipid Dispersions: Potential Delivery System for Functional Ingredients in Foods
Authors: Asumadu‐Mensah Aboagyewa , Smith Kevin W. , Ribeiro Henelyta S.
Published: July 2013

Structured solid lipid (SL) systems have the advantages of long‐term physical stability, low surfactant concentrations, and may exhibit controlled release of active ingredients. In this research work, the potential use of high‐melting SLs for the production of the above structured SL carrier systems was investigated. Dispersions containing either SL or blend of solid lipid and oil (SL+O) were produced by a hot melt high‐pressure homogenization method. Experiments involved the use of 3 different SLs for the disperse phase: stearic acid, candelilla wax and carnauba wax. Sunflower oil was incorporated in the disperse phase for the production of the dispersions containing lipid and oil. In order to evaluate the practical aspects of structured particles, analytical techniques were used including: static light scattering to measure particle sizes, transmission electron microscopy (TEM) for investigating particle morphology and differential scanning calorimetry (DSC) to investigate the crystallization behavior of lipids in bulk and in dispersions. Results showed different mean particle sizes depending on the type of lipid used in the disperse phase. Particle sizes for the 3 lipids were: stearic acid (SL: 195 ± 2.5 nm; SL+O: 138 ± 6.0 nm); candelilla wax (SL: 178 ± 1.7 nm; SL+O: 144 ± 0.6 nm); carnauba wax (SL: 303 ± 1.5 nm; SL+O: 295 ± 5.0 nm). TEM results gave an insight into the practical morphology, showing plate‐like and needle‐like structures. DSC investigations also revealed that SL dispersions melted and crystallized at lower temperatures than the bulk. This decrease can be explained by the small particle sizes of the dispersion, the high‐specific surface area, and the presence of a surfactant.
Computational Simulation of Alternative Photographic Processes
Authors: Echevarria Jose I. , Wilensky Gregg , Krishnaswamy Aravind , Kim Byungmoon , Gutierrez Diego
Published: July 2013

We present a novel computational framework for physically and chemically‐based simulations of analog alternative photographic processes. In the real world, these processes allow the creation of very personal and unique depictions due to the combination of the chemicals used, the physical interaction with liquid solutions, and the individual craftsmanship of the artist. Our work focuses not only on achieving similar compelling results, but on the manual process as well, introducing a novel exploratory approach for interactive digital image creation and manipulation. With such an emphasis on the user interaction, our simulations are devised to run on tablet devices; thus we propose the combination of a lightweight data‐driven model to simulate the chemical reactions involved, with efficient fluids simulations that modulate them. This combination allows realistic gestures‐based user interaction with constant visual feedback in real‐time. Using the proposed framework, we have built two prototypes with different tradeoffs between realism and flexibility, showing its potential to build novel image editing tools.
Automatic Cinemagraph Portraits
Authors: Bai Jiamin , Agarwala Aseem , Agrawala Maneesh , Ramamoorthi Ravi
Published: July 2013

Cinemagraphs are a popular new type of visual media that lie in‐between photos and video; some parts of the frame are animated and loop seamlessly, while other parts of the frame remain completely still. Cinemagraphs are especially effective for portraits because they capture the nuances of our dynamic facial expressions. We present a completely automatic algorithm for generating portrait cinemagraphs from a short video captured with a hand‐held camera. Our algorithm uses a combination of face tracking and point tracking to segment face motions into two classes: gross, large‐scale motions that should be removed from the video, and dynamic facial expressions that should be preserved. This segmentation informs a spatially‐varying warp that removes the large‐scale motion, and a graph‐cut segmentation of the frame into dynamic and still regions that preserves the finer‐scale facial expression motions. We demonstrate the success of our method with a variety of results and a comparison to previous work.
Spherical Visibility Sampling
Authors: Eikel Benjamin , Jähn Claudius , Fischer Matthias , auf der Heide Friedhelm Meyer
Published: July 2013

Many 3D scenes (e.g. generated from CAD data) are composed of a multitude of objects that are nested in each other. A showroom, for instance, may contain multiple cars and every car has a gearbox with many gearwheels located inside. Because the objects occlude each other, only few are visible from outside. We present a new technique, Spherical Visibility Sampling (SVS), for real‐time 3D rendering of such – possibly highly complex – scenes. SVS exploits the occlusion and annotates hierarchically structured objects with directional visibility information in a preprocessing step. For different directions, the directional visibility encodes which objects of a scene's region are visible from the outside of the regions' enclosing bounding sphere. Since there is no need to store a separate view space subdivision as in most techniques based on preprocessed visibility, a small memory footprint is achieved. Using the directional visibility information for an interactive walkthrough, the potentially visible objects can be retrieved very efficiently without the need for further visibility tests. Our evaluation shows that using SVS allows to preprocess complex 3D scenes fast and to visualize them in real time (e.g. a Power Plant model and five animated Boeing 777 models with billions of triangles). Because SVS does not require hardware support for occlusion culling during rendering, it is even applicable for rendering large scenes on mobile devices.
Exponential Soft Shadow Mapping
Authors: Shen Li , Feng Jieqing , Yang Baoguang
Published: July 2013

In this paper we present an image‐based algorithm to render visually plausible anti‐aliased soft shadows in real time. Our technique employs a new shadow pre‐filtering method based on an extended exponential shadow mapping theory. The algorithm achieves faithful contact shadows by adopting an optimal approximation to exponential shadow reconstruction function. Benefiting from a novel overflow free summed area table tile grid data structure, numerical stability is guaranteed and error filtering response is avoided. By integrating an adaptive anisotropic filtering method, the proposed algorithm can produce high quality smooth shadows both in large penumbra areas and in high frequency sharp transitions, meanwhile guarantee cheap memory consumption and high performance.
Interactive Lighting Design with Hierarchical Light Representation
Authors: Lin Wen‐Chieh , Huang Tsung‐Shian , Ho Tan‐Chi , Chen Yueh‐Tse , Chuang Jung‐Hong
Published: July 2013

Lighting design plays a crucial role in indoor lighting design, computer cinematograph and many other applications. Computer‐assisted lighting design aims to find a lighting configuration that best approximates the illumination effect specified by designers. In this paper, we present an automatic approach for lighting design, in which discrete and continuous optimization of the lighting configuration, including the number, intensity, and position of lights, are achieved. Our lighting design algorithm consists of two major steps. The first step estimates an initial lighting configuration by light sampling and clustering. The initial light clusters are then recursively merged to form a light hierarchy. The second step optimizes the lighting configuration by alternatively selecting a light cut on the light hierarchy to determine the number of representative lights and optimizing the lighting parameters using the simplex method. To speed up the optimization computation, only illumination at scene vertices that are important to rendering are sampled and taken into account in the optimization. Using the proposed approach, we develop a lighting design system that can compute appropriate lighting configurations to generate the illumination effects iteratively painted and modified by a designer interactively.
Developments in budget remote sensing for the geosciences
Authors: Carrivick Jonathan L. , Smith Mark W. , Quincey Duncan J. , Carver Steve J.
Published: July 2013

Acquiring outcrop, landform or other surface topography data in the field for the geosciences has always been challenging. Accessibility is often a problem, time is usually limited and an ideal spatial and temporal coverage often has to be compromised to be more manageable. However, emerging technologies, and some re‐inventions of rather older ones, can overcome many of these constraints in a very exciting and budget‐friendly manner. This article briefly introduces and reviews four major recent developments in budget remote sensing, specifically the use of blimps, kites, drones or UAVs (including quadcopters), and structure from motion (SFM) software. Both scientific and applied case studies are given and some possibilities for future studies are highlighted. Overall, the potential for these technologies to revolutionise the geosciences is clear and should be opportunistically embraced by scientists, resource and hazard managers and educators alike.
The Miocene of Carriacou, the Grenadines, Lesser Antilles
Authors: Donovan Stephen K. , Jackson Trevor A.
Published: July 2013

Carriacou is one of the small islands in the Grenadine chain in the southern Lesser Antilles. It preserves two Miocene successions, that on the south coast shallowing upwards and separated by a probable fault from the extensively exposed turbidite sequence, called the Grand Bay Formation, on the east coast. These formations show a range of features beautifully exposed in coastal sections, including unconformities, turbidites and a starfish bed.
Precarious delegates: irregular forms of employee interest representation in Germany
Authors: Artus Ingrid
Published: July 2013

The highly unionised dual model of industrial relations no longer represents the reality of employee representation in Germany. This article explores the case of irregular workplace delegates in service sector industries where the unionised dual model of employee representation is weakly entrenched. Identifying different configurations of the difficult employee access to co‐determination in precarious services, it argues for a differentiated view of the increasingly fragmented reality of national systems of employee representation.
The Possibilities of Forgiveness
Authors: Couenhoven Jesse
Published: July 2013

Perhaps the best way to challenge anodyne popular conceptions of forgiveness is to highlight the ways in which “forgiveness,” like “justice” and “freedom,” is a rich and deeply contested term that relies for its content on divergent convictions about who we are and who we should seek to be. The essays in this focus issue articulate some of the many possibilities for practicing and thinking about forgiveness.
The Neo‐Barthian Critique of Reinhold Niebuhr
Authors: Santurri Edmund N.
Published: July 2013

The author notes an unclarity in David Novak's defense of Reinhold Niebuhr against Stanley Hauerwas's critique and identifies some issues left unsettled in the exchange between Novak and Hauerwas over Niebuhr's ethics. Specifically, the author proposes that the Barthian‐Hauerwasian communitarian rejection of Niebuhrian natural theology and natural law ignores the historical abuse of biblical theology in the German Christian response to the Nazis, fails to account for the fact of general moral revulsion against Nazism, and flirts itself with a conventionalist form of nihilism.
Niebuhr One More Time
Authors: Hauerwas Stanley
Published: July 2013

In this essay Stanley Hauerwas offers a response to Edmund Santurri's review of Reinhold Niebuhr's An Interpretation of Christian Ethics.
Response to Edmund N. Santurri
Authors: Novak David
Published: July 2013

Barth and Niebuhr seemed to be wary of natural law because each of them thought that the “natural” in natural law means that natural law has to be rooted in natural theology. However, natural law today is more cogently formulated without any natural theology at all. “Natural law” means that law can be derived from the twofold character or nature of human personhood: the capacity for a communal relationship with other humans, and the capacity for a covenantal relationship with God, both of which continually overlap in human life. The natural or external world only provides the backdrop for these human capacities; it does not determine them.
Prolegomena zur Konzeptionalisierung unzuverlässigen Erzählens im Werk Hermann Hesses mit Schwerpunkt auf demSteppenwolf
Authors: Landgren Gustav
Published: July 2013

Vorliegender Beitraguntersucht Voraussetzungen, Formen und Funktionen unzuverlässigen Erzählens im Werk Hermann Hesses mit Schwerpunkt auf demSteppenwolf. Wegen seiner kompliziertenmise en abyme‐Konstruktion – in der Theorienbildung eine bisher stiefmütterlich behandelte Form unzuverlässigen Erzählens – bietet der Roman ein interessantes Beispiel für narrative Unzuverlässigkeit. Unzuverlässiges Erzählen lässt sich imSteppenwolfunter anderem anhand der doppelten Botschaft der Ironie erklären. Diese äußert sich v.a. im „Traktat vom Steppenwolf “ durch die Ironisierung traditioneller Erzählerwartungen: Was der Erzähler in der traditionellen Form des Traktats erwartet, wird durch paratextuelle Signale ironisch verworfen. Schon Hallers wertende Beschreibung des Traktats als ein „dünnes, schlecht, auf schlechtem Papier gedrucktes Jahrmarktsbüchlein“ die sich „nur an Verrückte“ wendet, kündigt Unzuverlässigkeit an. Eine andere prägnante Textstelle im Hinblick auf unzuverlässiges Erzählen ist die „Hochjagd auf Automobile“, an welcher der ehemalige Pazifist Haller teilnimmt. Als eine typisch unzuverlässige Erzählinstanz gilt hier der zwanghafte oder verrückte Monologist („mad monologist“), mit welchem Haller viele Merkmale teilt. Besonders die Ich‐Fixierung des Protagonisten ist ein Kriterium, das auf zahlreiche „mad monologists“ wie auch auf Haller zutrifft.

Im Gegensatz zur Neigung der Moderne zum Tendenzlos‐Nützlichen und Technisch‐Ökonomischen arbeitet Hesse imSteppenwolfsowie später in derMorgenlandfahrtmit mimetisch unentscheidbarem Erzählen, mit Widersprüchen hinsichtlich dessen, was in der erzählten Welt als wahr anzunehmen ist. Diese Form unzuverlässigen Erzählens gipfelt im Magischen Theater, in welchem sich die erzählte Welt in einer Serie alternativer Versionen auflöst. Unzuverlässiges Erzählen, laut Tom Kindt eng mit der literarischen Moderne verbunden, erweist sich in vorliegendem Beitrag als ein wichtiges Stilmittel im Spätwerk Hesses.
Thermo-Fluid Dynamics of an Array of Impinging Ionic Jets in a Crossflow
Authors: Testi Daniele , Grassi Walter
Published: July 2013

Laminar to weakly turbulent mixed convection in a square duct heated from the bottom side is highly strengthened by ionic jets generated by an array of high voltage points, opposite to the heated strip. Negative ion injection is activated within the dielectric liquid HFE-7100. Local temperatures on the heated wall are measured by liquid crystal thermography. Distributions of the Nusselt number are obtained at different forced flow rates, applied heat flows, and transiting electrical currents. In correspondence of the point emitters, higher Nusselt numbers in the impingement areas are measured and an analogy with the thermo-fluid dynamic behavior of an array of submerged impinging jets in a crossflow is drawn. The diameter of the ionic jets is evaluated and an electrohydrodynamic Reynolds number is employed for correlation and similarity purposes. Potential applications of the technique are high-efficiency compact heat exchangers and heat sinks.
Similarity Solution for Heat Convection From a Porous Rotating Disk in a Flow Field
Authors: Kendoush Abdullah Abbas
Published: July 2013

A mathematical method is described for the analytical solution of the convective heat transfer rates from a rotating isothermal and porous disk in a uniform flow field. By applying the appropriate velocity component of the fluid in the energy equation, a similarity solution was derived showing an increase in the rates of heat transfer with increasing rotational Reynolds number and with decreasing flow Reynolds number. Effects of natural convection and viscous dissipation were assumed negligible.
Analytical Solution for 2D Non-Fickian Transient Mass Transfer With Arbitrary Initial and Periodic Boundary Conditions
Authors: Suo Yaohong , Shen Shengping
Published: July 2013

Two-dimensional non-Fickian diffusion equation is solved analytically under arbitrary initial condition and two kinds of periodic boundary conditions. The concentration field distributions are analytically obtained with a form of double Fourier series, and the damped diffusion wave transport is discussed. At the same time, the numerical simulation is carried out for the problem with homogeneous boundary condition and arbitrary initial condition, which shows that the concentration field gradually changes from the initial distribution to the steady distribution and it changes faster for the smaller Vernotte number. The numerical results agree well with the experimental results.
Visualizing Non-Linear Control System Performance by Means of Multidimensional Scaling
Authors: Machado J. A. Tenreiro
Published: July 2013

This paper addresses the use of multidimensional scaling in the evaluation of controller performance. Several nonlinear systems are analyzed based on the closed loop time response under the action of a reference step input signal. Three alternative performance indices, based on the time response, Fourier analysis, and mutual information, are tested. The numerical experiments demonstrate the feasibility of the proposed methodology and motivate its extension for other performance measures and new classes of nonlinearities.
Quasi-Linear Control Approach to Designing Step Tracking Controllers for Systems With Saturating Actuators
Authors: Kabamba Pierre T. , Meerkov Semyon M. , Ossareh Hamid R.
Published: July 2013

This paper provides a novel method for designing step tracking controllers for systems with saturating actuators. The approach is based on the theory of Quasi-linear Control (QLC), which offers methods for designing random reference tracking controllers for systems with nonlinear actuators and sensors. In the current paper, a QLC approach to designing step tracking controllers is presented. The development is based on two ideas: introducing a precompensator, which observes given step tracking specifications, and recasting the output of the precompensator into a random reference bandwidth requirement, with subsequent utilization of QLC. Unlike other techniques, the method developed here takes the saturation into account directly at the initial stage of the design and does not require subsequent augmentations (e.g., anti-windup). Nevertheless, for the sake of completeness, a comparison with the anti-windup approach is provided.
Optical and Electronic Simulation of Silicon/Germanium Tandem Four Terminal Solar Cells
Authors: Vijayakumar Vishnuvardhanan , Birnie, III Dunbar P.
Published: July 2013

A tandem solar cell architecture of silicon and germanium solar cells in a mechanical (stack like) arrangement is evaluated to increase the efficiency of light absorption in the far infrared region from 1107 nm to 1907 nm wavelength, which constitutes about 14.5% of the power intensity in the solar AM 1.5 spectrum. In this work, the technical feasibility of tandem solar cells is investigated. Here, we report on detailed electrical and optical simulations of this structure quantifying the various theoretical and practical loss mechanisms in the encapsulation, interfaces, and in the device and indicate that a relative efficiency improvement of 20% may be attainable with silicon and germanium solar cells in this configuration. The optical and electrical parameters for silicon and germanium simulation models were extracted from experimental devices and material vendors. The developed simulation models were validated by comparing the performance of stand-alone silicon and germanium solar cells with experimental devices reported in the literature.
Determining Edge of Failure of a Spinal Wear Bearing
Authors: Dooris Andrew , Potter Leigh , Ares Paul
Published: July 2013

Mechanical test samples are often characterized using time-varying loads, either through slow monotonic changes in quasi-static testing, or through more rapid cyclic changes in dynamic testing. Spinal implant static and fatigue strengths are typically evaluated using such protocols, including such as standards ASTM F1717, ASTM F2077, and ASTM F2346. In contrast, wear tests such as ASTM F2423 and ASTM F2624 and ISO 18192-1, apply a single set of loading parameters over millions of cycles. These parameters are selected based on known, but limited, physiologic data. Wear tests however may be very sensitive to input parameters. Moreover, variations in surgical technique, patient anatomy, and pathology greatly alter the loading environment on the device. Wear tests ideally would evaluate the device under both the expected duty cycle as well as under varying test parameters.
Effects of Surface Integrity on In-Vitro Corrosion of Biodegradable Magnesium-Calcium Orthopedic Implants
Authors: Salahshoor M. , Guo Y. B.
Published: July 2013

Biodegradable magnesium-calcium (MgCa) alloys are capable of gradually dissolving and becoming absorbed in the human body after implantation. The critical issue that hinders the application of MgCa implants is their fast corrosion rate in human body fluids. A promising approach to tackle this issue is to tailor surface integrity of orthopedic implants for tuning the corrosion kinetic. The synergistic dry cutting and burnishing is used in this study to modify surface integrity of MgCa0.8 (wt%) implants for controlled corrosion performance. The effects of cutting speed and rolling force, as key parameters in the synergistic dry cutting-finish burnishing, on the electrochemical responses of the processed surfaces are investigated in the simulated body fluid (SBF). Potentiodynamic polarization curves are measured, and morphology and elemental composition of corroded surfaces are studied utilizing scan electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively.