bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supervisory control of uncertain systems with quantized information
Authors: Vu Linh , Liberzon Daniel 
Published: March 2012

SUMMARYThis work addresses the problem of stabilizing uncertain systems with quantized outputs using the supervisory control framework, in which a finite family of candidate controllers is employed together with an estimator‐based switching logic to select the active controller at every time. For static quantizers, we provide a relationship between the quantization range and the quantization error bound that guarantees closed‐loop stability. Such a condition also implies a lower bound on the number of information bits needed to guarantee stability of a supervisory control scheme with quantized information. For dynamic quantizers that can vary the quantization parameters in real time, we show that the closed loop can be asymptotically stabilized, provided that additional conditions on the quantization range and the quantization error bound are satisfied. Copyright © 2012 John Wiley & Sons, Ltd.
A signal processing adaptive algorithm for nonstationary power signal parameter estimation
Authors: Hasan Shazia , Dash P.K. , Nanda S. 
Published: March 2012

SUMMARYThis paper presents the design and analysis of an adaptive algorithm for tracking the amplitude, phase and frequency of the fundamental, harmonics and interharmonics present in time‐varying power sinusoid in white noise. If frequency, amplitude and phase of the multiple sinusoids become nonstationary, they are estimated as an unconstrained optimization problem using robust and low complexity multi‐objective Gauss–Newton algorithm. The presented algorithm deals with frequency drift and can accurately estimate frequency variation, amplitude and phase variation, as well as harmonic amplitude and phase variations. Further, the learning parameters in the proposed algorithm are tuned iteratively to provide faster convergence and better accuracy. The excellent tracking capability of proposed multi‐objective Gauss–Newton algorithm is shown through simulation and experimental results in a nonstationary environment. Copyright © 2012 John Wiley & Sons, Ltd.
Halogen Bonding versus Hydrogen Bonding in Driving Self‐Assembly and Performance of Light‐Responsive Supramolecular Polymers
Authors: Priimagi Arri , Cavallo Gabriella , Forni Alessandra , Gorynsztejn–Leben Mikael , Kaivola Matti , Metrangolo Pierangelo , Milani Roberto , Shishido Atsushi , Pilati Tullio , Resnati Giuseppe , Terraneo Giancarlo 
Published: March 2012

AbstractHalogen bonding is arguably the least exploited among the many non‐covalent interactions used in dictating molecular self‐assembly. However, its directionality renders it unique compared to ubiquitous hydrogen bonding. Here, the role of this directionality in controlling the performance of light‐responsive supramolecular polymers is highlighted. In particular, it is shown that light‐induced surface patterning, a unique phenomenon occurring in azobenzene‐containing polymers, is more efficient in halogen‐bonded polymer–azobenzene complexes than in the analogous hydrogen‐bonded complexes. A systematic study is performed on a series of azo dyes containing different halogen or hydrogen bonding donor moieties, complexed to poly(4‐vinylpyridine) backbone. Through single‐atom substitution of the bond‐donor, control of both the strength and the nature of the noncovalent interaction between the azobenzene units and the polymer backbone is achieved. Importantly, such substitution does not significantly alter the electronic properties of the azobenzene units, hence providing us with unique tools in studying the structure–performance relationships in the light‐induced surface deformation process. The results represent the first demonstration of light‐responsive halogen‐bonded polymer systems and also highlight the remarkable potential of halogen bonding in fundamental studies of photoresponsive azobenzene‐containing polymers.
Estrogenic plant foods of red colobus monkeys and mountain gorillas in uganda
Authors: Wasserman Michael D. , Taylor‐Gutt Alexandra , Rothman Jessica M. , Chapman Colin A. , Milton Katharine , Leitman Dale C. 
Published: March 2012

AbstractPhytoestrogens, or naturally occurring estrogen‐mimicking compounds, are found in many human plant foods, such as soybeans (Glycine max) and other legumes. Because the consumption of phytoestrogens may result in both health benefits of protecting against estrogen‐dependent cancers and reproductive costs of disrupting the developing endocrine system, considerable biomedical research has been focused on the physiological and behavioral effects of these compounds. Despite this interest, little is known about the occurrence of phytoestrogens in the diets of wild primates, nor their likely evolutionary importance. We investigated the prevalence of estrogenic plant foods in the diets of two folivorous primate species, the red colobus monkey (Procolobus rufomitratus) of Kibale National Park and mountain gorilla (Gorilla beringei) of Bwindi Impenetrable National Park, both in Uganda. To examine plant foods for estrogenic activity, we screened 44 plant items (species and part) comprising 78.4% of the diet of red colobus monkeys and 53 plant items comprising 85.2% of the diet of mountain gorillas using transient transfection assays. At least 10.6% of the red colobus diet and 8.8% of the gorilla diet had estrogenic activity. This was mainly the result of the red colobus eating three estrogenic staple foods and the gorillas eating one estrogenic staple food. All estrogenic plants exhibited estrogen receptor (ER) subtype selectivity, as their phytoestrogens activated ERβ, but not ERα. These results demonstrate that estrogenic plant foods are routinely consumed by two folivorous primate species. Phytoestrogens in the wild plant foods of these two species and many other wild primates may have important implications for understanding primate reproductive ecology. Am J Phys Anthropol, 2012. © 2012 Wiley Periodicals, Inc.
Application and performance of maleated thermoplastic starch–poly(butylene adipate‐co‐terephthalate) blends for films
Authors: Stagner Jacqueline A. , Alves Vanessa Dias , Narayan Ramani 
Published: March 2012

AbstractIn this work, we studied the effect of the percentage of maleated thermoplastic starch (MTPS) in MTPS–poly(butylene adipate‐co‐terephthalate) (PBAT) blends that were used to produce extruded films. The materials were characterized by their mechanical properties (tensile and puncture tests), their barrier properties (carbon dioxide, oxygen, and water‐vapor permeability tests), and microstructural analysis [transmission electron microscopy (TEM)], and the biobased content of the materials was determined. The results of the testing show that increasing the MTPS content decreased the tensile strength (from 19.7 to 8.6 MPa in the machine direction and from 15.3 to 7.1 MPa in the transverse direction) and puncture force (from 42.5 to 30.3 N) of the films; however, the elongation was not significantly affected. The permeability of the films to oxygen and carbon dioxide decreased with increasing MTPS content. The oxygen permeability decreased from 1.68 × 10−17 to 6.0 × 10−18 kg m m−2 s−1 Pa−1, whereas the carbon dioxide permeability decreased from 3.0 × 10−16 to 1.1 × 10−16 kg m m−2 s−1 Pa−1. However, the permeability to water vapor increased from 5.0 × 10−15 to 1.04 × 10−14 kg m m−2 s−1 Pa−1. Finally, TEM showed that PBAT was the continuous phase and MTPS was the dispersed phase. As the amount of MTPS in the samples increased, the dispersed phase became finer and more regularly spaced. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and characterizations of a latent polyhedral oligomeric silsequioxane‐containing catalyst and its application in polybenzoxazine resin
Authors: Wang Lei , Du Wenjie , Wu Yixian , Xu Riwei , Yu Dingsheng 
Published: March 2012

AbstractIn this article, a novel latent curing agent, octa(paratoluenesulfonic acid ammomium salt) (OPAAS) polyhedral oligomeric silsequioxane was synthesized and used in modifying the polybenzoxazine/2,2′‐(1,3‐phenylene)‐bis(4,5‐dihydro‐oxazoles) (PBO) (PBZ/PBO) resin. The liberated octa(aminophenyl) silsesquioxane and paratoluenesulfonic acid can catalyze the ring‐opening reaction of benzoxazine (BZ) resin. The initial curing temperature (Ti), peak curing temperature (Tp) and the Enthalpy of the curing temperature had significantly decreased with respect to pristine BZ/PBO resin. When the OPAAS amount was 3 wt %, the peak curing temperature decreased from 233.7 to 218.2°C. Also, PBZ/PBO/OPAAS composites exhibited better storage modulus than pure PBZ/PBO resin. Meanwhile, PBZ/PBO/OPAAS composites are more thermally stable than PBZ/PBO resin. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Plasma surface modification of porous PLLA films: Analysis of surface properties and in vitro hydrolytic degradation
Authors: Mattioli S. , Kenny J. M. , Armentano I. 
Published: March 2012

AbstractThe aim of this research was to investigate the effects of plasma treatment on the surface and on the in vitro degradation behavior of poly(L‐lactide) (PLLA) films. Polymer films were prepared by solvent casting, and their surface was modified by radiofrequency plasma treatments by using oxygen and tetrafluorocarbon gas. Pristine and treated PLLA films were characterized by field emission and atomic force microscopy and by contact angle measurements. In vitro hydrolytic degradation studies were conducted by measurements of weight loss, water absorption, visual inspection, and thermal transitions as a function of the incubation time. As‐deposited PLLA films show a uniform distribution of ring‐like porous structures on the surface due to solvent evaporation. Plasma treatments produce a mass reduction following the etching of the polymer surface. Moreover, the morphology of the porous polymer is modified by the plasma, which induces different micro/nanometric topographic reliefs as a function of the different selected plasma processing parameters. The results indicate PLLA surface become hydrophilic and the surface roughness increased with treatment time in the case of oxygen, whereas a hydrophobic behavior was induced with tetrafluorocarbon plasma treatment. However, in vitro degradation studies show that plasma treatments do not affect the PLLA bulk and the hydrolytic degradation properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Newly evolved genes: Moving from comparative genomics to functional studies in model systems
Authors: Ranz José M. , Parsch John 
Published: March 2012

AbstractGenes are gained and lost over the course of evolution. A recent study found that over 1,800 new genes have appeared during primate evolution and that an unexpectedly high proportion of these genes are expressed in the human brain. But what are the molecular functions of newly evolved genes and what is their impact on an organism's fitness? The acquisition of new genes may provide a rich source of genetic diversity that fuels evolutionary innovation. Although gene manipulation experiments are not feasible in humans, studies in model organisms, such as Drosophila melanogaster, have shown that new genes can quickly become integrated into genetic networks and become essential for survival or fertility. Future studies of new genes, especially chimeric genes, and their functions will help determine the role of genetic novelty in the adaptation and diversification of species.
Reduced‐order modeling for cardiac electrophysiology. Application to parameter identification
Authors: Boulakia M. , Schenone E. , Gerbeau J‐F. 
Published: March 2012

SUMMARYA reduced‐order model based on proper orthogonal decomposition (POD) is proposed for the bidomain equations of cardiac electrophysiology. Its accuracy is assessed through electrocardiograms in various configurations, including myocardium infarctions and long‐time simulations. We show in particular that a restitution curve can efficiently be approximated by this approach. The reduced‐order model is then used in an inverse problem solved by an evolutionary algorithm. Some attempts are presented to identify ionic parameters and infarction locations from synthetic electrocardiograms. Copyright © 2012 John Wiley & Sons, Ltd.
Smoothed particle hydrodynamics method applied to pulsatile flow inside a rigid two‐dimensional model of left heart cavity
Authors: Shahriari S. , Kadem L. , Rogers B.D. , Hassan I. 
Published: March 2012

SUMMARYThis paper aims to extend the application of smoothed particle hydrodynamics (SPH), a meshfree particle method, to simulate flow inside a model of the heart's left ventricle (LV). This work is considered the first attempt to simulate flow inside a heart cavity using a meshfree particle method. Simulating this kind of flow, characterized by high pulsatility and moderate Reynolds number using SPH is challenging. As a consequence, validation of the computational code using benchmark cases is required prior to simulating the flow inside a model of the LV. In this work, this is accomplished by simulating an unsteady oscillating flow (pressure amplitude: A = 2500 N ∕ m3 and Womersley number: Wo = 16) and the steady lid‐driven cavity flow (Re = 3200, 5000). The results are compared against analytical solutions and reference data to assess convergence. Then, both benchmark cases are combined and a pulsatile jet in a cavity is simulated and the results are compared with the finite volume method. Here, an approach to deal with inflow and outflow boundary conditions is introduced. Finally, pulsatile inlet flow in a rigid model of the LV is simulated. The results demonstrate the ability of SPH to model complex cardiovascular flows and to track the history of fluid properties. Some interesting features of SPH are also demonstrated in this study, including the relation between particle resolution and sound speed to control compressibility effects and also order of convergence in SPH simulations, which is consistently demonstrated to be between first‐order and second‐order at the moderate Reynolds numbers investigated. Copyright © 2012 John Wiley & Sons, Ltd.
Application‐driven analysis of two generations of capability computing: the transition to multicore processors
Authors: Rajan Mahesh , Vaughan Courtenay T. , Doerfler Doug W. , Barrett Richard F. , Lin Paul T. , Pedretti Kevin T. , Scott Hemmert K. 
Published: March 2012

SUMMARYMulticore processors form the basis of most traditional high performance parallel processing architectures. Early experiences with these computers showed significant performance problems, both with regard to computation and inter‐process communication. The transition from Purple, an IBM POWER5‐based machine, to Cielo, a Cray XE6, as the main capability computing platform for the United States Department of Energy's Advanced Simulation and Computing campaign provides an opportunity to reexamine these issues after experiences with a few generations of multicore‐based machines. Experiences with Purple identified some important characteristics that led to strong performance of complex scientific application programs at very large scales. Herein, we compare the performance of some Advanced Simulation and Computing mission critical applications at capability scale across this transition to multicore processors. Copyright © 2012 John Wiley & Sons, Ltd.
Molecular MR Imaging of Collagen in Mouse Atherosclerosis by Using Paramagnetic CNA35 Micelles
Authors: van Bochove Glenda S. , Sanders Honorius M. H. F. , de Smet Mariska , Keizer Henk M. , Mulder Willem J. M. , Krams Rob , Strijkers Gustav J. , Nicolay Klaas 
Published: March 2012

AbstractMagnetic resonance imaging (MRI) is increasingly used in biomedicine to visualize plaques in the walls of major arteries in relation to atherosclerosis, the prime cause of myocardial infarction and ischemic stroke. The present study aims to explore the utility of contrast‐enhanced MRI for improving the specificity of the MRI evaluation of atherosclerotic plaques with the use of a Gd‐based paramagnetic contrast agent that is targeted to collagen. Collagen is a major component of the extracellular matrix and as such plays an important role in the stability of atherosclerotic plaques. Micelles were made with lipid containing 45 mol‐% Gd for MRI detection and a low mol fraction of fluorescent lipid for fluorescence microscopic analysis. Collagen‐targeted, functional micelles were prepared by conjugation of the CNA35 protein, while nonfunctional control micelles were conjugated with a mutated version of the protein. The micelles were characterized with respect to their magnetic, biochemical, and biophysical properties. Atherosclerotic plaques were induced in the right carotid artery of apo‐E knock‐out mice by surgical placement of a tapered polymeric cast. In vivo MRI was performed at 6.3 Tesla before and up to 24 h after intravenous injection of paramagnetic micelles (50 μmol Gd kg–1). MRI revealed the strongest signal enhancements by CNA35 micelles. At early time points after injection of CNA35 micelles, contrast enhancement was higher in the collagen‐richer lesions compared to that in the collagen‐poorer lesions. Confocal laser scanning microscopy confirmed co‐localization of CNA35 micelles and collagen in the plaques. We have demonstrated molecular MR imaging of collagen in experimental atherosclerosis by using a CNA35‐functionalized micellar contrast agent.
Stereocontrol with Lithium Trimethylzincate toward Gibberellin Synthesis (Eur. J. Org. Chem. 11/2012)
Authors: Isobe Minoru , Chiang Ching‐Te , Tsao Kuo‐Wei , Cheng Chia‐Yi , Bruening Reimar 
Published: March 2012

AbstractThe cover picture shows the North Gate of Hsinchu City, Taiwan, which has been preserved as a historical heritage site of the city, surrounded by modern electronic devices. The molecules shown include the synthesis of the A‐ring substructure of gibberellin, a plant hormone. The key reaction, the ability of lithium trimethylzincate to undergo conjugate addition, as discovered in 1977, was developed for the synthesis of the A‐ring in collaboration with Dr. Reimar Bruening in Nagoya University around 1980 (unpublished). Now, in 2012, this zincate chemistry has been used as the indispensable step at National Tsing Hua University. Zinc chemistry is surrounded by modern synthetic devices. Details are presented in the Short Communication by M. Isobe et al. on p. 2109 ff. Chia‐Yi Cheng is acknowledged for her help in designing this cover picture. magnified image
Path‐based Multipath Protection: resilience using multiple paths
Authors: Gyarmati László , Cinkler Tibor , Trinh Tuan Anh 
Published: March 2012

ABSTRACTThe Multipath Protection (MPP) network resilience methods route and protect the upcoming demand over multiple paths. Although these schemes are able to allocate resources efficiently in the network, the length of the paths that the packets traverse cannot be controlled. Accordingly, to control the latency of the connections, we reuse the idea of MPP when we propose the Path‐based Multipath Protection (PMPP) scheme. By controlling the maximal length of the paths, we increase the availability as well, because on shorter paths, fewer failures happen. The contribution of our work is threefold. First, we give the linear programming formulation of the PMPP method that does not have any integer variables resulting from polynomial runtime, similar to the former MPP methods. Second, we present extensive simulation results including the blocking ratios, the properties of the paths and the availabilities. Finally, we compare the PMPP resilience scheme with the original and improved versions of MPP method on the basis of several metrics. Copyright © 2012 John Wiley & Sons, Ltd.
METHODS FOR COVARIATE ADJUSTMENT IN COST‐EFFECTIVENESS ANALYSIS THAT USE CLUSTER RANDOMISED TRIALS
Authors: Gomes Manuel , Grieve Richard , Nixon Richard , Ng Edmond S.‐W. , Carpenter James , Thompson Simon G. 
Published: March 2012

SUMMARYStatistical methods have been developed for cost‐effectiveness analyses of cluster randomised trials (CRTs) where baseline covariates are balanced. However, CRTs may show systematic differences in individual and cluster‐level covariates between the treatment groups. This paper presents three methods to adjust for imbalances in observed covariates: seemingly unrelated regression with a robust standard error, a ‘two‐stage’ bootstrap approach combined with seemingly unrelated regression and multilevel models. We consider the methods in a cost‐effectiveness analysis of a CRT with covariate imbalance, unequal cluster sizes and a prognostic relationship that varied by treatment group. The cost‐effectiveness results differed according to the approach for covariate adjustment.A simulation study then assessed the relative performance of methods for addressing systematic imbalance in baseline covariates. The simulations extended the case study and considered scenarios with different levels of confounding, cluster size variation and few clusters. Performance was reported as bias, root mean squared error and CI coverage of the incremental net benefit. Even with low levels of confounding, unadjusted methods were biased, but all adjusted methods were unbiased. Multilevel models performed well across all settings, and unlike the other methods, reported CI coverage close to nominal levels even with few clusters of unequal sizes. Copyright © 2012 John Wiley & Sons, Ltd.
Building ambidexterity: The role of human resource practices in the performance of firms from Spain
Authors: Prieto Isabel M. , Pilar Pérez Santana M. 
Published: March 2012

AbstractBoth researchers and managers are increasingly interested in how firms can pursue ambidextrous learning—that is, simultaneously exploring new knowledge domains while exploiting current ones. In this study, we attempt to bring human resource management into this forum by introducing and testing how high‐involvement human resource practices shape the social climate that affects the firm's ambidextrous learning and subsequent performance. A field study of 198 companies from Spain showed that high‐involvement human resource practices were positively related to the social climate that, in turn, facilitates ambidextrous learning and improved performance. © 2012 Wiley Periodicals, Inc.
Perceived training intensity and knowledge sharing: Sharing for intrinsic and prosocial reasons
Authors: Kuvaas Bård , Buch Robert , Dysvik Anders 
Published: March 2012

AbstractThis study investigated the relationship between perceived training intensity and knowledge sharing, including the moderating roles of intrinsic motivation and social and economic exchange perceptions. Data from 310 employees working in three organizations located in Norway revealed a positive relationship between perceived training intensity and knowledge sharing for employees with low levels of intrinsic motivation and economic exchange perception, and high levels of social exchange perception. These findings suggest that perceived training intensity increases knowledge sharing only under specific motivational influences. Implications for practice and directions for future research are discussed. © 2012 Wiley Periodicals, Inc