bluuebunny/crossref_metadata_2025 huggingface dataset:
East‐west and vertical spectral asymmetry associated with equatorial type I waves during strong electrojet conditions: 2. Theory
Authors: St.‐Maurice J.‐P. , Choudhary R. K.
Published: November 2006

In order to explain vertical and east‐west type I asymmetries uncovered in a companion paper and in references therein, we introduce the notion that the generating large‐scale gradient drift waves break down first in elongated isolated enhancement and depletion regions (blobs and holes) that follow an asymmetric nonlinear evolution. The nonlinear evolution is accompanied by a rotation of the electric field inside the structures, be they blobs or holes. It is shown here that holes have a tendency to rotate more than blobs but that as a result the electric field inside holes is also weaker. These two features (contrasting rotations and contrasting field strengths) explain the predominant sign of the up‐down and east‐west asymmetries during weakly to moderately driven conditions. They also explain how the asymmetry is observed to disappear and even to reverse its sign under more strongly driven conditions.
Improved estimation of soil water retention characteristics from hydrostatic column experiments
Authors: Peters A. , Durner W.
Published: November 2006

The soil water retention characteristic, θ(h), is required for modeling and predicting water and solute transport in unsaturated porous media. Commonly, θ(h) is determined by relating pressure heads, h, to mean water contents, θ, that are measured in column experiments under hydrostatic equilibrium conditions and fitting a parametric retention function to these data pairs. Implicit to this method is the assumption that the mean water content of the column is equivalent to a point measurement in the column center. Dependent on the nonlinearity of the vertical water content distribution, θ(z), in the column, this assumption may be invalid and introduces a systematic error. A sensitivity analysis shows that the magnitude of the error caused by neglecting the nonlinearity of the water content distribution may reach several percent if coarse materials with low air entry values and tall soil columns are investigated. Furthermore, neglecting θ(z) yields a smoothed retention characteristic and thus may lead to wrong conclusions about the most appropriate parametric model for the water retention characteristic. If the hydraulic conductivity function K(h) is predicted from such an incorrect retention function, it can differ greatly from the true function. In this paper, we propose to consider the measured water content of a soil column explicitly as an integral of the equilibrium water content distribution with depth. We show that this eliminates systematic parameter estimation errors and leads to improved estimates of the soil water retention function.
Magnetoelectric coupling in epitaxial CoFe2O4 on BaTiO3
Authors: Chopdekar R. V. , Suzuki Y.
Published: November 2006

The authors have synthesized epitaxial CoFe2O4 films on piezoelectric BaTiO3 single crystal substrates as a model magnetoelectric system. The BaTiO3 substrate provides a surface lattice that can be dynamically changed in an attempt to alter the strain state and hence the magnetization of the CoFe2O4 film. Magnetization measurements indicate that the magnetic anisotropy of CoFe2O4 is dominated by compressive epitaxial strain effects and can be understood in terms of the symmetry of the substrate surface unit cell.
Solidlike spreading of a liquid/liquid system
Authors: Cheng Y. , Ye X. , Ma H. R.
Published: November 2006

The authors report an investigation of spreading of a polydimethylsiloxane oil drop on the surface of solution with very low Triton X-100 concentration. The spreading rate is found to be extremely lower than expected from the current theory. The spreading consists of two stages: the first stage has a precursor film formed which dissipates the redundant surface free energy and is responsible for the slow down of spreading rate as in the case of spreading on a solid surface, and the second stage is a normal spreading process on the liquid surface.
Analysis of elastic stability and structural response of face-centered cubic crystals subject to [110] loading
Authors: Djohari Hadrian , Milstein Frederick , Maroudas Dimitrios
Published: November 2006

The elastic stability and structural response of face-centered cubic crystals subject to uniaxial [110] loading are investigated systematically based on lattice-statics analysis, molecular-dynamics (MD) simulations, and symmetry and bifurcation considerations. The onset of instability in isostress MD simulations is found to be associated with loss or diminution of energy convexity (Born’s stability criterion) as determined from computed strain and temperature dependent elastic moduli. Atomic mechanisms of crystal destabilization beyond the onset of instability are consistent with theoretical eigendeformations and are precursors to interatomic slip, which, in turn, may lead to failure or mechanical stacking faults.
All-optical switching in the near infrared with bacteriorhodopsin-coated microcavities
Authors: Topolancik Juraj , Vollmer Frank
Published: November 2006

Photoinduced molecular transitions in bacteriorhodpsin are used to reversibly configure a micron-scale photonic component in which the optical response is resonantly enhanced. The chromophore retinal undergoes photoinduced all-trans to 13-cis conformational change, which tunes resonances in a silica microsphere coated with three bacteriorhodopsin monolayers. The tunable, all-optical resonant coupler reroutes a near-infrared beam (λprobe≅1311nm) between two tapered optical fibers using a low-power (<200μW) green pump (λpump=532nm). The approach represents a bottom-up paradigm for fabrication of hybrid molecular-photonic architectures that employ self-assembled biomolecules for optical manipulation at small scales.
High temperature integrated ultrasonic shear wave probes
Authors: Jen C.-K. , Ono Y. , Kobayashi M.
Published: November 2006

Integrated ultrasonic shear wave probes have been fabricated using steel substrates through a paint-on method with the use of mode conversion from longitudinal to shear waves. The probe can be operated up to 150°C. A probe simultaneously generating and receiving both longitudinal and shear waves is also demonstrated.
Bi
Fe
O
3
film deposited on Si substrate buffered with La0.7Sr0.3MnO3 electrode
Authors: Wang D. H. , Yan L. , Ong C. K. , Du Y. W.
Published: November 2006

A multilayer film of BiFeO3∕La0.7Sr0.3MnO3∕SrTiO3 was deposited on Si substrate by pulsed laser deposition method, in which La0.7Sr0.3MnO3 was used as a bottom electrode. X-ray diffraction showed that the film was polycrystalline. From the x-ray photoelectron spectroscopy measurement, the valence number of the Fe ion was found to be 3+. The BiFeO3 film showed a low leakage-current density, and a large twice remanent polarization (2Pr) of 110μC∕cm2 was observed at room temperature. Owing to the ferromagnetic and magnetostrictive properties of La0.7Sr0.3MnO3, this multilayer film system is a promising candidate for the study of magnetoelectric coupling.
Surface energy and shrinkage of a nanocavity
Authors: Ouyang G. , Tan X. , Cai M. Q. , Yang G. W.
Published: November 2006

An analytical model was developed for the size dependence of surface energy of a nanocavity from the perspective of thermodynamics and continuum medium mechanics. Three components of the liquidlike matrix, vaporlike cavity, and inner surface skin of the cavity were considered for the cavity-matrix structure, and contribution from chemical and structural effects to the surface energy was discussed. It was found that the surface energy increases with the inverse of cavity size and that the cavity shrinks in size, differing from what is usually expected. It was suggested that the surface skin be stronger than the matrix because of the bond order deficiency effect.
Coherent near-infrared wavelength conversion in semiconductor quantum cascade lasers
Authors: Zervos C. , Frogley M. D. , Phillips C. C. , Kundys D. O. , Wilson L. R. , Cockburn J. W. , Hopkinson M. , Skolnick M. S.
Published: November 2006

A scheme for generating coherent “sidebands” on a near-infrared optical carrier beam is demonstrated experimentally, using a modified quantum cascade laser. The active region of the laser simultaneously provides the gain, generates one of the optical fields, and provides a doubly resonant second-order nonlinear optical medium. This allows coherent sideband generation with normal incidence coupling and with interaction lengths sufficiently short to be immune to phase-matching problems. The resulting electrically modulatable two-terminal device offers a means of performing various all-optical routing, switching, and detection operations of interest for optical telecommunications.
Substrate Selectivity of Epidermal Growth Factor-Receptor Ligand Sheddases and their Regulation by Phorbol Esters and Calcium Influx
Authors: Horiuchi Keisuke , Le Gall Sylvain , Schulte Marc , Yamaguchi Takafumi , Reiss Karina , Murphy Gillian , Toyama Yoshiaki , Hartmann Dieter , Saftig Paul , Blobel Carl P.
Published: November 2006

Signaling via the epidermal growth factor receptor (EGFR), which has critical roles in development and diseases such as cancer, is regulated by proteolytic shedding of its membrane-tethered ligands. Sheddases for EGFR-ligands are therefore key signaling switches in the EGFR pathway. Here, we determined which ADAMs (a disintegrin and metalloprotease) can shed various EGFR-ligands, and we analyzed the regulation of EGFR-ligand shedding by two commonly used stimuli, phorbol esters and calcium influx. Phorbol esters predominantly activate ADAM17, thereby triggering a burst of shedding of EGFR-ligands from a late secretory pathway compartment. Calcium influx stimulates ADAM10, requiring its cytoplasmic domain. However, calcium influx-stimulated shedding of transforming growth factor α and amphiregulin does not require ADAM17, even though ADAM17 is essential for phorbol ester-stimulated shedding of these EGFR-ligands. This study provides new insight into the machinery responsible for EGFR-ligand release and thus EGFR signaling and demonstrates that dysregulated EGFR-ligand shedding may be caused by increased expression of constitutively active sheddases or activation of different sheddases by distinct stimuli.
OmicBrowse: a browser of multidimensional omics annotations
Authors: Toyoda Tetsuro , Mochizuki Yoshiki , Player Keith , Heida, Norio Kobayashi Naohiko , Sakaki Yoshiyuki
Published: November 2006

Summary: OmicBrowse is a browser to explore multiple datasets coordinated in the multidimensional omic space integrating omics knowledge ranging from genomes to phenomes and connecting evolutional correspondences among multiple species. OmicBrowse integrates multiple data servers into a single omic space through secure peer-to-peer server communications, so that a user can easily obtain an integrated view of distributed data servers, e.g. an integrated view of numerous whole-genome tiling-array data retrieved from a user's in-house private-data server, along with various genomic annotations from public internet servers. OmicBrowse is especially appropriate for positional-cloning purposes. It displays both genetic maps and genomic annotations within wide chromosomal intervals and assists a user to select candidate genes by filtering their annotations or associated documents against user-specified keywords or ontology terms. We also show that an omic-space chart effectively represents schemes for integrating multiple datasets of multiple species.

Availability: OmicBrowse is developed by the Genome-Phenome Superbrain Project and is released as free open-source software under the GNU General Public License at

Contact:  toyop@gsc.riken.go.jp
Estimatingp-values in small microarray experiments
Authors: Yang Hyuna , Churchill Gary
Published: November 2006

Motivation: Microarray data typically have small numbers of observations per gene, which can result in low power for statistical tests. Test statistics that borrow information from data across all of the genes can improve power, but these statistics have non-standard distributions, and their significance must be assessed using permutation analysis. When sample sizes are small, the number of distinct permutations can be severely limited, and pooling the permutation-derived test statistics across all genes has been proposed. However, the null distribution of the test statistics under permutation is not the same for equally and differentially expressed genes. This can have a negative impact on both p-value estimation and the power of information borrowing statistics.

Results: We investigate permutation based methods for estimating p-values. One of methods that uses pooling from a selected subset of the data are shown to have the correct type I error rate and to provide accurate estimates of the false discovery rate (FDR). We provide guidelines to select an appropriate subset. We also demonstrate that information borrowing statistics have substantially increased power compared to the t-test in small experiments.

Contact:  garyc@jax.org

Supplementary information: Supplementary data are available at Bioinformatics online.
Dependence network modeling for biomarker identification
Authors: Qiu Peng , Wang Z. Jane , Liu K. J. Ray , Hu Zhang-Zhi , Wu Cathy H.
Published: November 2006

Motivation: Our purpose is to develop a statistical modeling approach for cancer biomarker discovery and provide new insights into early cancer detection. We propose the concept of dependence network, apply it for identifying cancer biomarkers, and study the difference between the protein or gene samples from cancer and non-cancer subjects based on mass-spectrometry (MS) and microarray data.

Results: Three MS and two gene microarray datasets are studied. Clear differences are observed in the dependence networks for cancer and non-cancer samples. Protein/gene features are examined three at one time through an exhaustive search. Dependence networks are constructed by binding triples identified by the eigenvalue pattern of the dependence model, and are further compared to identify cancer biomarkers. Such dependence-network-based biomarkers show much greater consistency under 10-fold cross-validation than the classification-performance-based biomarkers. Furthermore, the biological relevance of the dependence-network-based biomarkers using microarray data is discussed. The proposed scheme is shown promising for cancer diagnosis and prediction.

Availability: See supplements:

Contact:  qiupeng@umd.edu
Towards clustering of incomplete microarray data without the use of imputation
Authors: Kim Dae-Won , Lee Ki-Young , Lee Kwang H. , Lee Doheon
Published: November 2006

Motivation: Clustering technique is used to find groups of genes that show similar expression patterns under multiple experimental conditions. Nonetheless, the results obtained by cluster analysis are influenced by the existence of missing values that commonly arise in microarray experiments. Because a clustering method requires a complete data matrix as an input, previous studies have estimated the missing values using an imputation method in the preprocessing step of clustering. However, a common limitation of these conventional approaches is that once the estimates of missing values are fixed in the preprocessing step, they are not changed during subsequent processes of clustering; badly estimated missing values obtained in data preprocessing are likely to deteriorate the quality and reliability of clustering results. Thus, a new clustering method is required for improving missing values during iterative clustering process.

Results: We present a method for Clustering Incomplete data using Alternating Optimization (CIAO) in which a prior imputation method is not required. To reduce the influence of imputation in preprocessing, we take an alternative optimization approach to find better estimates during iterative clustering process. This method improves the estimates of missing values by exploiting the cluster information such as cluster centroids and all available non-missing values in each iteration. To test the performance of the CIAO, we applied the CIAO and conventional imputation-based clustering methods, e.g. k-means based on KNNimpute, for clustering two yeast incomplete data sets, and compared the clustering result of each method using the Saccharomyces Genome Database annotations. The clustering results of the CIAO method are more significantly relevant to the biological gene annotations than those of other methods, indicating its effectiveness and potential for clustering incomplete gene expression data.

Availability: The software was developed using Java language, and can be executed on the platforms that JVM (Java Virtual Machine) is running. It is available from the authors upon request.

Contact:  dwkim@cau.ac.kr
Neurologic and histologic outcome after intraneural injections of lidocaine in canine sciatic nerves
Authors: Kapur E. , Vuckovic I. , Dilberovic F. , Zaciragic A. , Cosovic E. , Divanovic K.‐A. , Mornjakovic Z. , Babic M. , Borgeat A. , Thys D. M. , Hadzic A.
Published: November 2006

Background:  Inadvertent intraneural injection of local anesthetics may result in neurologic injury. We hypothesized that an intraneural injection may be associated with higher injection pressures and an increase in the risk of neurologic injury.

Methods:  The study was conducted in accordance with the principles of laboratory animal care, and was approved by the Laboratory Animal Care and Use Committee. Fifteen dogs of mixed breed (16–21 kg) were studied. After general endotracheal anesthesia, the sciatic nerves (n= 30) were exposed bilaterally. Under direct vision, a 25‐gauge, long‐beveled needle (30°) was placed either epineurally (n= 10) or intraneurally (n= 20), and 4 ml of preservative‐free lidocaine 20 mg/ml was injected using an automated infusion pump (4 ml/min). Injection pressure data were acquired using an in‐line manometer coupled to a computer via an analog‐to‐digital conversion board. After injection, the animals were awakened and subjected to serial neurologic examinations. One week later, the dogs were killed, the sciatic nerves excised and histologic examination was performed by pathologists blind to the purpose of the study.

Results:  All perineural injections resulted in low pressures (≤ 5 psi). In contrast, eight of 20 intraneural injections resulted in high pressures (20–38 psi) at the beginning of the injection. Twelve intraneural injections, however, resulted in pressures of less than 12 psi. Neurologic function returned to baseline within 3 h after perineural injections and within 24 h after intraneural injections, when the measured injection pressures were less than 12 psi. Neurologic deficits persisted throughout the study period after all eight intraneural injections that resulted in high injection pressures. Histologic examination of the affected nerves revealed fascicular axonolysis and cellular infiltration.

Conclusions:  The data in our canine model of intraneural injection suggest that intraneural injections do not always lead to nerve injury. High injection pressures during intraneural injection may be indicative of intrafascicular injection and may predict the development of neurologic injury.
A new and efficient one-pot solid-supported synthesis of 1,2,4,6-tetraaryl-1,4-dihydropyridines
Authors: Verma Anil K , Koul Summon , Razdan Tej K , Kapoor Kamal K
Published: November 2006

1,2,4,6-Tetraaryl-1,4-dihydropyridines were obtained by the one-pot reaction of chalcones and substituted anilines on the surface of Bi(III)nitrate-Al2O3. The reaction seems to proceed via β-oxygenation of Bi(III) enolised chalcones followed by Michael addition and heteroannulation with simultaneous retro aldol disproportionation. The presence of the ring-activating groups at ortho and para positions in the aniline seems to be essential for the reaction.Key words: 1,2,4,6-tetraryl-1,4-dihydropyridines, chalcones, substituted anilines, Bi(III) nitrate-alumina catalyst.
Isomerization of 4-amino-6,7-diphenylbicyclo[2.2.2]octan-2-ones
Authors: Seebacher Werner , Saf Robert , Brun Reto , Kaiser Marcel , Weis Robert
Published: November 2006

Under strongly basic conditions (6SR,7SR)-4-amino-6,7-diphenylbicyclo[2.2.2]octan-2-ones isomerized regioselectively in position 6 giving their (6RS,7SR) analogues. The structure of the new products was established with the aid of NMR experiments.Key words: aminobicyclo[2.2.2]octanones, isomerization, structure elucidation.
STRUCTURAL, ELECTRONIC AND QSAR PROPERTIES OF THE CYFLUTHRIN MOLECULE: A THEORETICAL AM1 AND PM3 TREATMENT
Authors: ÇALIŞIR EMİNE DENİZ , ERKOÇ ŞAKİR
Published: November 2006

Cyfluthrin is a synthetic cyano-containing pyrethroid insecticide that has both contact and stomach poison action. It is a nonsystemic chemical used to control cutworms, ants, silverfish, cockroaches, mosquitoes, tobacco budworm and many others. Its primary agricultural uses have been for control of chewing and sucking insects on crops such as cotton, turf, ornamentals, hops, cereal, corn, deciduous fruit, peanuts, potatoes, and other vegetables. Cyfluthrin is also used in public health situations and for structural pest control. The structural, vibrational, electronic and QSAR properties of the cyfluthrin molecule in gas phase have been investigated theoretically by performing molecular mechanics method by using MM+ force field, and semi-empirical molecular orbital AM1 and PM3 calculations. The geometry of the molecule has been optimized, infrared spectrum (vibrational modes and intensities) and the electronic properties of the molecule have been calculated in its ground state. According to PM3 calculation, heat of formation of cyfluthrin molecule is about -48.58 kcal/mol (exothermic), which shows that this molecule thermodynamically be stable. The HOMO energy level for this molecule is found to be -9.701 eV and the LUMO energy level is -0.660 eV giving rise to a gap of 9.041 eV, which also indicates that cyfluthrin is thermodynamically stable.
THE LANDAU DISTRIBUTION FOR CHARGED PARTICLES TRAVERSING THIN FILMS
Authors: MARUCHO M. , GARCIA CANAL C. A. , FANCHIOTTI HUNER
Published: November 2006

The Landau distribution as well as its first and second momenta are well suited for describing the energy loss of charged particles traversing a thin layer of matter. At present, just rational approximations and asymptotic expressions for these functions were obtained. In this paper we present a direct calculation of the integral representation of these functions obtaining perturbative and nonperturvative solutions expressed in terms of fast convergent series. We also provide a simple numerical algorithm which allows to control speed and precision of the results. The testing runs have provided, in reasonable computing times, correct results up to 13-14 significant digits on the density and distribution functions and 9-10 on the first and second momenta. If necessary, this accuracy could be improved by adding more coefficients to the algorithm.
STATISTICAL PROPERTIES OF ONLINE AUCTIONS
Authors: NAMAZI ALIREZA , SCHADSCHNEIDER ANDREAS
Published: November 2006

We characterize the statistical properties of a large number of online auctions run on eBay. Both stationary and dynamic properties, like distributions of prices, number of bids etc., as well as relations between these quantities are studied. The analysis of the data reveals surprisingly simple distributions and relations, typically of power-law form. Based on these findings we introduce a simple method to identify suspicious auctions that could be influenced by a form of fraud known as shill bidding. Furthermore the influence of bidding strategies is discussed. The results indicate that the observed behavior is related to a mixture of agents using a variety of strategies.
FROM LOGNORMAL DISTRIBUTION TO POWER LAW: A NEW CLASSIFICATION OF THE SIZE DISTRIBUTIONS
Authors: BENGUIGUI LUCIEN , BLUMENFELD-LIEBERTHAL EFRAT
Published: November 2006

We propose a new classification of the size distributions of entities based on an exponent α defined from the shape of the log–log Rank Size plot. From an inspection of a large number of cases in different fields, one finds three possibilities: α = 1 giving a power law, α > 1 (parabola like curve) and 0 < α < 1 (analogous to a log normal distribution). A fourth possibility that can be defined when α < 0 was never observed. We present a modified version of models based on a random multiplicative process and an introduction of new entities during the growth. We recover all three kinds of distributions and show that the type of a distribution is conditioned by the rate of the introduction of new entities.
THE ŁOJASIEWICZ EXPONENT AT AN EQUILIBRIUM POINT OF A STANDARD CNN IS 1/2
Authors: FORTI MAURO , TESI ALBERTO
Published: November 2006

In the sixties, Łojasiewicz proved a fundamental inequality for vector fields defined by the gradient of an analytic function, which gives a lower bound on the norm of the gradient in a neighborhood of a (possibly) non-isolated critical point. The inequality involves a number belonging to (0, 1), which depends on the critical point, and is known as the Łojasiewicz exponent. In this paper, a class of vector fields which are defined on a hypercube of ℝn, is considered. Each vector field is the gradient of a quadratic function in the interior of the hypercube, however it is discontinuous on the boundary of the hypercube. An extended Łojasiewicz inequality for this class of vector fields is proved, and it is also shown that the Łojasiewicz exponent at each point where a vector field vanishes is equal to 1/2. The considered fields include a class of vector fields which describe the dynamics of the output trajectories of a standard Cellular Neural Network (CNN) with a symmetric neuron interconnection matrix. By applying the extended Łojasiewicz inequality, it is shown that each output trajectory of a symmetric CNN has finite length, and as a consequence it converges to an equilibrium point. Furthermore, since the Łojasiewicz exponent at each equilibrium point of a symmetric CNN is equal to 1/2, it follows that each (state) trajectory, and each output trajectory, is exponentially convergent toward an equilibrium point, and this is true even in the most general case where the CNN possesses infinitely many nonisolated equilibrium points. In essence, the obtained results mean that standard symmetric CNNs enjoy the property of absolute stability of exponential convergence.
PERIODIC WAVES AND THEIR LIMITS FOR THE CAMASSA–HOLM EQUATION
Authors: LIU ZHENGRONG , KAYED ALI MOHAMMED , CHEN CAN
Published: November 2006

In this paper, the bifurcation method of dynamical systems is employed to study the Camassa–Holm equation [Formula: see text] We investigate the periodic wave solutions of form u = φ(ξ) which satisfy φ(ξ + T) = φ(ξ), here ξ = x - ct and c, T are constants. Their six implicit expressions and two explicit expressions are obtained. We point out that when the initial values are changed, the periodic waves may become three waves, periodic cusp waves, smooth solitary waves and peakons. Our results give an explanation to the appearance of periodic cusp waves and peakons. Moreover, three sets of graphs of the implicit functions are drawn, and three sets of numerical simulations are displayed. The identity of these graphs and simulations imply the correctness of our theoretical results.
AN OPTIMIZATION METHOD INSPIRED BY "CHAOTIC" ANT BEHAVIOR
Authors: LI LIXIANG , YANG YIXIAN , PENG HAIPENG , WANG XIANGDONG
Published: November 2006

Inspired by the behavior of the ants in nature, we propose an optimization method, which combines the chaotic behavior of individual ants with the intelligent optimization action of an ant colony. Our method includes both effects of chaotic dynamics and swarm-based search. It is a deterministic process different from the conventional ant algorithm. The nonlinear dynamics of the proposed method are analyzed, and we show how the algorithm, called chaotic ant swarm optimization, can be applied to numerical optimization problems with encouraging results.
MODELING NATURAL SHAPES WITH A SIMPLE NONLINEAR ALGORITHM
Authors: CHACÓN RICARDO
Published: November 2006

Concerning the problem of shape and pattern description, a compact formula (Gielis' formula) has recently been proposed that generates a vast diversity of natural shapes. However, this formula is a modified version of the equation for the circle, so that it is expressed in terms of trigonometric functions which are inherent to linear phenomena but rarely appear in the description of nonlinear phenomena. In this work, two examples of simple mathematical formulas which are natural nonlinear modifications (one being a generalization) of Gielis' formula are discussed. These formulas involve a comparable number of parameters and provide non-Platonic representations of a vast diversity of natural shapes and patterns by incorporating diverse aspects of asymmetry and seeming disorder which are absent in the original Gielis' formula. It is also shown how diverse sequences resembling some natural-world pattern evolutions are also generated by such nonlinear formulas.
HYPERCHAOS IN A SIMPLE CNN
Authors: LI QINGDU , YANG XIAO-SONG , YANG FANGYAN
Published: November 2006

In this paper we demonstrate hyperchaotic dynamics in a very simple Cellular Neural Network (CNN) which is a one-dimensional regular array of four cells. The Lyapunov spectrum is calculated in a range of parameters, and the bifurcation plot is presented as well.
Interstitial Nucleus of Cajal Encodes Three-Dimensional Head Orientations in Fick-Like Coordinates
Authors: Klier Eliana M. , Wang Hongying , Crawford J. Douglas
Published: November 2006

Two central, related questions in motor control are 1) how the brain represents movement directions of various effectors like the eyes and head and 2) how it constrains their redundant degrees of freedom. The interstitial nucleus of Cajal (INC) integrates velocity commands from the gaze control system into position signals for three-dimensional eye and head posture. It has been shown that the right INC encodes clockwise (CW)-up and CW-down eye and head components, whereas the left INC encodes counterclockwise (CCW)-up and CCW-down components, similar to the sensitivity directions of the vertical semicircular canals. For the eyes, these canal-like coordinates align with Listing’s plane (a behavioral strategy limiting torsion about the gaze axis). By analogy, we predicted that the INC also encodes head orientation in canal-like coordinates, but instead, aligned with the coordinate axes for the Fick strategy (which constrains head torsion). Unilateral stimulation (50 μA, 300 Hz, 200 ms) evoked CW head rotations from the right INC and CCW rotations from the left INC, with variable vertical components. The observed axes of head rotation were consistent with a canal-like coordinate system. Moreover, as predicted, these axes remained fixed in the head, rotating with initial head orientation like the horizontal and torsional axes of a Fick coordinate system. This suggests that the head is ordinarily constrained to zero torsion in Fick coordinates by equally activating CW/CCW populations of neurons in the right/left INC. These data support a simple mechanism for controlling head orientation through the alignment of brain stem neural coordinates with natural behavioral constraints.
Temporal Processing of Saccade Targets in Parietal Cortex Area LIP During Visual Search
Authors: Thomas Neil W. D. , Paré Martin
Published: November 2006

We studied whether the lateral intraparietal (LIP) area—a subdivision of parietal cortex anatomically interposed between visual cortical areas and saccade executive centers—contains neurons with activity patterns sufficient to contribute to the active process of selecting saccade targets in visual search. Visually responsive neurons were recorded while monkeys searched for a color-different target presented concurrently with seven distractors evenly distributed in a circular search array. We found that LIP neurons initially responded indiscriminately to the presentation of a visual stimulus in their response fields, regardless of its feature and identity. Their activation nevertheless evolved to signal the search target before saccade initiation: an ideal observer could reliably discriminate the target from the individual activation of 60% of neurons, on average, 138 ms after stimulus presentation and 26 ms before saccade initiation. Importantly, the timing of LIP neuronal discrimination varied proportionally with reaction times. These findings suggest that LIP activity reflects the selection of both the search target and the targeting saccade during active visual search.
Identification of a gene network contributing to hypertrophy in callipyge skeletal muscle
Authors: Vuocolo Tony , Byrne Keren , White Jason , McWilliam Sean , Reverter Antonio , Cockett Noelle E. , Tellam Ross L.
Published: November 2006

The callipyge mutation in sheep results in postnatal skeletal muscle hypertrophy in the pelvic limbs and loins with little or no effect on anterior skeletal muscles. Associated with the phenotype are changes in the expression of a number of imprinted genes flanking the site of the mutation, which lies in an intergenic region at the telomeric end of ovine chromosome 18. The manner in which these local changes in gene expression are translated into muscle hypertrophy is not known. Microarray-based transcriptional profiling was used to identify differentially expressed genes in longissimus dorsi skeletal muscle samples taken at birth and 12 wk of age from callipyge and wild-type sheep. The phenotype was only expressed at the latter developmental time and associated with decreased type 1 fibers (slow oxidative) and a shift toward type IIx and IIb fibers (fast-twitch glycolytic). We have identified 131 genes in the samples taken at 12 wk of age that were differentially expressed as a function of genotype but not due to the fiber type changes. The gene expression changes occurring as a function of genotype in the samples taken at birth indicated that the transcriptional framework underpinning the phenotype was emerging prior to expression of the phenotype. Eight genes were differentially expressed as a function of genotype at both developmental times. A model is proposed describing a core network of genes and histone epigenetic modifications that is likely to underpin the fiber type changes and muscle hypertrophy characteristic of callipyge sheep.
Churches and social development
Authors: Nieman Anna
Published: November 2006

English

The role of churches is explored against the background of poverty and inequality in South Africa. The value of empowerment to counter the negative effects of traditional forms of welfare aid is explained. The case is made for churches to collaborate with other institutions and groups to undertake joint social development programmes.

French

Le rôle des églises face à la pauvreté et à l'inégalité en Afrique du sud est examiné. L'article explique la valeur accordée au principe 'd'empowerment' dans le but de contrer les effets négatifs des formes traditionnelles d'aide sociale. Il est démontré que les églises doivent collaborer avec d'autres institutions et groupes dans le développement de programmes conjoints d'aide sociale.

Spanish

La función de las iglesias es explorada teniendo como fondo de partida la pobreza y la inequidad en Sudáfrica. El valor del empoderamiento (empowerment) para contrarrestar los efectos negativos de las formas tradicionales de ayuda es explicada. Se argumenta que las iglesias tienen que colaborar con otras instituciones y grupos para el desarrollo de programas de desarrollo social conjunto.
Difficulties of stepchildren from reconstituted families in a westernized society challenged by traditional Chinese culture
Authors: Lam Gladys L.T.
Published: November 2006

English

Reconstituted families in Hong Kong are negatively stereotyped by Chinese families holding traditional beliefs. This article contains extracted findings of pioneer studies on Hong Kong reconstituted families and the author's observations from her private practice as a family mediator. It is hoped that timely intervention will be promoted to help stepchildren affected by negative social attitudes.

French

Les familles reconstituées à Hong Kong sont négativement stéréotypées par les familles chinoises aux croyances traditionnelles. Cet article contient des résultats d'études pionnières faites à Hong Kong auprès de familles reconstituées ainsi que des observations faites par l'auteur dans sa pratique en tant que médiatrice familiale. L'auteur fait la promotion d'interventions faites en temps opportun afin d'aider ces enfants souffrant d'attitudes sociales négatives à leur égard.

Spanish

Familias reconstituidas en Hong Kong son estereotipadas por familias chinas que poseen valores y creencias tradicionales. Este artículo presenta extractos de hallazgos de estudios pioneros en Hong Kong sobre las familias reconstituidas y de las observaciones hechas por el autor en su práctica privada como mediador familiar. Se espera que intervenciones a debido tiempo deben ser promovidos para ayudas a los hijastros que has sido impactados por las actitudes sociales negativas.
Terrorists versus the Government
Authors: Siqueira Kevin , Sandler Todd
Published: November 2006

This article focuses on the strategic interaction between a terrorist group and a government as both vie for grassroots support. When terrorists and the government act contemporaneously, the equilibrium outcome depends on the effectiveness of the government’s countermeasures and the ability of the government to curb popular support of the terrorists through public spending. In two alternative scenarios, the authors establish that leadership may improve both adversaries’ well-being while reducing terrorism. The leader changes in the two cases, with the weaker player going first to the advantage of both players. State sponsorship and franchising of terrorists augment violence as both adversaries expend more effort. Sponsors can offset some strategic limits to violence that competition for supporters offers.
Echoes of Vietnam?
Authors: Boettcher William A. , Cobb Michael D.
Published: November 2006

In the early stages of the counterinsurgency campaign in Iraq, military leaders resisted the release of body count and “casualty ratio” data. However, in the spring of 2004, the U.S. military (and American media) began to focus on the “limited” American casualties in specific operations versus the “significant” number of insurgents killed. This article examines the extent to which body count/casualty ratio “frames” and individual casualty tolerance influence public perceptions about the war and the success or failure of U.S. military operations. Two experiments were conducted pitting alternative casualty frames against one another to measure their relative impact. The results demonstrate the influence of framing effects on public perceptions and clarify understanding of the determinants and impact of casualty tolerance.
On Terrorism and Electoral Outcomes
Authors: Berrebi Claude , Klor Esteban F.
Published: November 2006

This article investigates the interaction between terror attacks and electoral outcomes in Israel. The authors analyze a dynamic model of reputation that captures the salient characteristics of this conflict. The equilibrium of the theoretical model generates two precise empirical predictions about the interaction between terrorism and electoral outcomes. First, the relative support for the right-wing party is expected to increase after periods with high levels of terrorism and to decrease after periods of relative calm. Second, the expected level of terrorism is higher when the left-wing party is in office than it is during the term of the right-wing party. The authors test these hypotheses by using a newly created data set on terrorist attacks in Israel between 1990 and 2003. The first hypothesis is strongly supported by data culled from public opinion polls about the Israeli electorate’s political preferences. The second theoretical hypothesis is strongly supported by the three Israeli governments to which the theory can be applied that served during the studied time period.
Cheap Signals with Costly Consequences
Authors: Thyne Clayton L.
Published: November 2006

This article examines the effect of interstate signals on the probability of civil war onset. Using a bargaining framework, the author argues that costly signals should have no effect on the likelihood that a civil war begins because they allow the government and opposition to peacefully adjust their bargaining positions to avoid the costs of fighting. In contrast, cheap signals can disrupt intrastate negotiations, which makes conflict more likely by increasing the likelihood that one of the competing parties will make excessive demands. This argument is tested using measures for sanctions, troop mobilization, alliances, and trade ties as indicators for costly signals, as well as events data as measures for cheap signals. Results demonstrate that cheap signals strongly affect the probability of civil war onset, while costly signals do not. Cheap signals hostile to the government increase the likelihood of civil war onset, while cheap supportive signals have a pacifying effect.
Helping Because You Have To or Helping Because You Want To? Sustaining Participation in Service Work From Adolescence Through Young Adulthood
Authors: Planty Mike , Bozick Robert , Regnier Michael
Published: November 2006

This article examines whether the motive behind community service performed during high school—either voluntary or required—influences engagement in volunteer work during the young adult years. Using a sample of students from the National Education Longitudinal Study of 1988 ( N= 9,966), service work in high school is linked with community service in young adulthood. The findings show that participation in community service declines substantially in the 2 years following high school graduation but then rebounds slightly once members of the sample reach their mid-20s. In general, community service participation in high school was related to volunteer work both 2 and 8 years after high school graduation. However, those who were required to participate in community service while in high school were only able to sustain involvement 8 years after graduation if they reported that their participation was voluntary. Strengths and limitations of the analysis as well as implications for youth policy are discussed.
The Silent Erosion: Anti-Terror Laws and Shifting Contours of Jurisprudence in India
Authors: Singh Ujjwal Kumar
Published: November 2006

The repeal of the Prevention of Terrorism Act, 2002 (POTA) figured prominently in the Common Minimum Programme (CMP) of the United Progressive Alliance (UPA), the coalition that replaced the National Democratic Alliance (NDA) government in May 2004. On 21 September 2004, the President promulgated an Ordinance repealing POTA a month before it was to come up for legislative review. The Ordinance was approved by the Parliament in its winter session confirming the removal of POTA from the statute books.
May I Get the Door for You? An Ethnographic Take on the Labor of Doormen
Authors: Fine Gary Alan
Published: November 2006

This article reviews Peter Bearman’s ethnographic research on the characteristics of residential doormen. In this occupational case study, Bearman relies on the well-established Chicago school in discussing how doormen enact a variety of professional responsibilities beyond the obvious roles of security and surveillance. Bearman argues that doormen are also keen impression managers who must delicately negotiate the social dynamics that are an inevitable consequence of residential life in large buildings. This includes strategically balancing power and humility as well as handling contentious political and labor issues.
Rethinking Occupational Structure
Authors: Damarin Amanda Kidd
Published: November 2006

This article addresses the structure of occupations in flexible work settings by examining the case of Web site production. Web work does not exhibit traditional occupations: Rather than falling within bounded task jurisdictions, Web jobs and careers involve fluid combinations of multiple task sets. Furthermore, workers identify less with particular specialties than with Web production as a whole. Fluid jobs allow workers some autonomy in production, but little control over the wider organization of work. This suggests that flexibility may generate new occupational structures and new contradictions for workers, but comparison with prior research suggests that occupations have never been entirely uniform.
Mechanical Behavior of Isothalic Polyester-based Untreated Woven Jute and Glass Fabric Hybrid Composites
Authors: Ahmed K. Sabeel , Vijayarangan S. , Rajput Chhaya
Published: November 2006

In this study, the effect of hybridization on mechanical properties of untreated (as received) woven jute and glass fabric-reinforced isothalic polyester composites has been evaluated experimentally. Hybrid laminates are fabricated using hand lay-up technique. The specimen preparation and testing are carried out as per ASTM standards. The values of mechanical properties of hybrid composites plotted against glass fiber weight fraction show significant improvement after the inclusion of glass fiber. Addition of 16.5 wt% glass fiber, in a total fiber weight fraction of 42% enhances the tensile, flexural, and interlaminar shear strength (ILSS) by 37, 31.23, and 17.6% respectively. The behavior of the composite under different tests is analyzed with the help of performance curves. Water absorption plots for different periods of immersion indicated that jute– glass hybrid composites offer better resistance to water absorption. The results of fractographic tests carried out to study the modes of fracture, fiber–matrix adhesion, and jute–glass layer adhesion are also presented.
An Analysis of Weakly Bonded Laminated Cylindrical Panels
Authors: Rattanawangcharoen N.
Published: November 2006

A finite-element model for accurate stress analysis of perfectly and weakly bonded laminated cylindrical panels is presented. This model is based on the three-dimensional theory of elasticity. Both stress and displacement components are used as degrees of freedom. Shear slip and normal separation are employed to model weak interfacial bonding by the concept of a linear spring. The effect of the weakness of the interface, the fiber-orientation angle, and the panel thickness and shallowness on the displacements and stresses of angle-ply laminated cylindrical panels are studied.
Dynamic Response of 3D Biaxial Spacer Weft-knitted Composite under Transverse Impact
Authors: Liu Yuanwan , Lv Lihua , Sun Baozhong , Hu Hong , Gu Bohong
Published: November 2006

The transverse impact of 3D biaxial spacer weft-knitted reinforced fabric composite is performed with a split Hopkinson pressure bar. The load versus displacement history of the composite under different impact velocities is obtained. The failure load and failure deformation both increase with the increasing of impact velocity. The energy absorption of the composite also increases with the increasing of impact velocity. The failure mode of the composite is compression failure in the front side and tension failure in the distal side. The matrix crack, fiber pullout and form interface debonding form the main failure mode for transverse impact loading. The composite has no delamination either for quasi-static loading or for transverse impact loading.