bluuebunny/crossref_metadata_2025 huggingface dataset:
SURFACE-INITIATED ATOM TRANSFER RADICAL POLYMERIZATION OF HYDROXYETHYL ACRYLATE FROM ACTIVATED CARBON POWDER WITH HOMOGENIZED SURFACE GROUPS
Authors: LIU PENG , WANG TINGMEI
Published: July 2007

The well-defined poly(hydroxyethyl acrylate) (PHEA) brushes were grafted from the surfaces of the activated carbon (AC) powder with the controlled/"living" radical polymerization technique. First, surface functional groups of the AC powder were homogenized to hydroxyl groups by oxidizing with nitric acid and then reducing with lithium tetrahydroaluminate ( LiAlH 4) at first. Second, the surface hydroxyl groups were treated with bromoacetylbromide, and the bromoacetyl groups were introduced. And in the third step, the bromoacetyl activated carbon ( BrA-AC ) powder were used as macro-initiators for the surface-initiated atom transfer radical polymerization (SI-ATRP) of hydroxyethyl acrylate (HEA) in the presence of 1,10-phenanthroline and Cu(I)Br as catalyst in a water system. The graft parameters calculated from the elemental analyses (EA) results, conversion of monemer (C%) and percentage of grafting (PG%) were 5.74% and 28.7%, respectively, after polymerizing for 5 h. The graft polymerizations exhibited the characteristics of a controlled/"living" polymerization, and no homopolymer was found in the proposed polymerizing process. The preparation procedure of the poly(hydroxyethyl acrylate) grafted activated carbon (PHEA-AC) powder was also investigated by X-ray photoelectron spectroscopy (XPS). The PHEA-AC powder is expected to be used as selective adsorbents because of their abundant homogenized surface hydroxyl groups.
EFFECTS OF La DOPING ON FERROELECTRIC PROPERTIES OF CaBi4Ti4O15 THIN FILMS
Authors: DING YANXIA , HU GUANGDA , FAN SUHUA
Published: July 2007

La modified CBTi ( CLBTi ) thin films were prepared on Pt/Ti/SiO 2/ Si (100) substrates by a sol–gel technique. X-ray diffraction analysis showed that single phase of CLBTi thin films were obtained. Their crystallization and hysteresis behavior were strongly dependent on the La contents. An increase of 2Pr as well as a decrease of 2Ec with the increase of La concentration were observed. The leakage properties of CBTi thin films were found to be improved by the La doping. The results were discussed with respect to the effects of La 3+ substitution at perovskite A-site.
A DC PLASMA DISCHARGE SOURCE AND ITS APPLICATION TO SYNTHESIS OF CARBON AND CARBON NITRIDE THIN FILMS
Authors: YANG B. Q. , FENG P. X.
Published: July 2007

In the present work, a novel DC glow discharge source with configurations of hollow cathode electrodes had been developed. Discharge properties of the plasma source had been characterized. Experimental data indicated that the discharge current of the plasma source increased with the discharge voltage. The phase change of the discharge was observed with the increase of gas pressures. After characterization, the hollow cathode electrodes was used to sputtering deposition of both carbon and carbon nitride films.

All samples were characterized by using Raman scattering spectroscopy. Typical D- and G-bands in the Raman spectrum of the samples were identified. In the case of carbon nitride films, the intensity ratio of D- and G-bands changed greatly with the deposition period of time. The shifts of D- and G-ands were also observed. In the case of carbon films, the intensity ratio of D- and G-bands slightly increased with an increase of the helium gas pressure from 100 to 200 Pa. The peak positions of the bands remained nearly unchanged with the variation of the helium gas pressure.
IN SITU SYNTHESIS OF TiC–TiB2 REINFORCED FeCrSiB COMPOSITE COATING BY LASER CLADDING
Authors: DU BAOSHUAI , ZOU ZENGDA , WANG XINHONG , LI QINGMING
Published: July 2007

TiC and TiB 2 reinforced iron based metal matrix composite (MMC) coating was synthesized on mild carbon steel by laser cladding employing B 4 C , ferrotitanium, and FeCrSiB mixed powders. The microstructure and chemical composition were analyzed by means of SEM, EPMA, and XRD. Results show that the coating mainly consists of α– Fe(Ni) , TiB 2, TiC , B 6 Fe 23, Cr 2 B , and M 23 C 6. TiB 2, and TiC reinforcements are formed in situ through the reaction between B 4 C and ferrotitanium. Hardness and wear measurement results show that the hardness and wear resistance of the composites are much higher than that of the as-received sample.
DEVELOPMENT OF DIRECT METHODS OF DATA INVERSION IN HELIUM ATOM SCATTERING
Authors: SHUTTLEWORTH I. G.
Published: July 2007

The problem of diffraction pattern deconvolution in Helium Atom Scattering (HAS) has been solved directly within the Eikonal approximation. A formulation based on the Patterson construction has been developed which reduces the problem to the solution of a set of simultaneous equations in {ζj}, where ζj are the corrugation parameters for the surface. The formulation returns real space structures that satisfy unitarity, a secondary problem in HAS diffraction image inversion. Numerical benchmarks of this procedure are presented.
STOCHASTIC INTENSITY MODELING FOR STRUCTURED CREDIT EXOTICS
Authors: CHAPOVSKY ALEXANDER , RENNIE ANDREW , TAVARES PEDRO
Published: July 2007

We propose a class of credit models where we model default intensity as a jump-diffusion stochastic process. We demonstrate how this class of models can be specialised to value multi-asset derivatives such as CDO and CDO2 in an efficient way. We also suggest how it can be adapted to the pricing of option on tranche and leverage tranche deals. We discuss how the model performs when calibrated to the market.
JOINT DISTRIBUTIONS OF PORTFOLIO LOSSES AND EXOTIC PORTFOLIO PRODUCTS
Authors: EPPLE FRIEDEL , MORGAN SAM , SCHLOEGL LUTZ
Published: July 2007

The pricing of exotic portfolio products, e.g. path-dependent CDO tranches, relies on the joint probability distribution of portfolio losses at different time horizons. We discuss a range of methods to construct the joint distribution in a way that is consistent with market prices of vanilla CDO tranches. As an example, we show how our loss-linking methods provide estimates for the breakeven spreads of forward-starting tranches. .
LÉVY SIMPLE STRUCTURAL MODELS
Authors: BAXTER MARTIN
Published: July 2007

This paper considers credit portfolio models based on Levy processes in general, and the gamma model in particular. It describes both single-name and multi-name situations using the gamma model, along with calibration fits and a comparison of various simple Levy models. There is also extensive historical data, including the May 2005 Auto crisis, which can be described in terms of the model. Parameter-based risk management using the gamma model is also discussed along with implementation details.
PRICING AND HEDGING IN A DYNAMIC CREDIT MODEL
Authors: ELOUERKHAOUI YOUSSEF
Published: July 2007

In this paper, we present a methodology for pricing and hedging portfolio credit derivatives in a dynamic credit model. Starting with a single-name Marshall–Olkin framework, we build a dynamic top-down version of the model, which is tractable and preserves the intuition of the original setting. In the first part of the paper, we derive analytically the Fourier transform of the loss variable and we study the skew dynamics implied by the model. In the second part, we develop a theory for dynamic hedging of portfolio credit derivatives. Since the market is incomplete, due to the residual correlation risk, perfect replication cannot be achieved. To find the hedging strategies, we use a quadratic risk minimization criterion.
Price Discovery across the Stock Index Futures and the ETF Markets: Intra-Day Evidence from the S&P 500, Nasdaq-100 and DJIA Indices
Authors: Hseu Mei-Maun , Chung Huimin , Sun Erh-Yin
Published: July 2007

This paper investigates the intra-day price dynamics of the S&P 500, Nasdaq-100 and DJIA indices for the periods both before and after the Nasdaq market crash which occurred between March 2000 and March 2001. We explore the relative price efficiencies of the three indices in the spot, futures, E-mini futures and ETF markets, and find that a cointegrating relationship existed between the three indices during the period after the crash. This would seem to imply that in the aftermath of the crash, the three indices shared common macroeconomic fundamentals.

We find that where there is some disturbance in the equilibrium relationship between the indices, the market which adjusts to retain equilibrium is the Nasdaq-100 market. In the long run, the S&P 500 index leads the other index contracts, a finding which is consistent with the trading cost hypothesis. Nevertheless, the Nasdaq-100 index retains short-run price leadership over both the S&P 500 and DJIA indices.
ABSOLUTE CONTINUITY FOR SOLUTIONS TO STOCHASTIC FUNCTIONAL DIFFERENTIAL EQUATIONS WITH JUMPS
Authors: TAKEUCHI ATSUSHI
Published: July 2007

We study absolute continuity for the probability law of solutions to stochastic functional differential equations driven by Lévy processes: [Formula: see text] where Xt is the path defined by Xt(s) = X(t+s) for s ∈ [-r, 0]. We apply methods from the Malliavin calculus on the Poisson space to show that non-degenerate conditions on A1, …, Am of the noise term guarantee the existence of densities.
REGULARITY PROPERTIES OF THE DONSKER–VARADHAN RATE FUNCTIONAL FOR NON-REVERSIBLE DIFFUSIONS AND RANDOM EVOLUTIONS
Authors: PINSKY ROSS G.
Published: July 2007

The Donsker–Varadhan rate functional I(μ) for Markov processes has a simple form in the case that the generator of the process is self-adjoint, or equivalently, that the Markov process is reversible. In particular, in the case of a reversible diffusion generated by a second-order elliptic operator L on a compact manifold, this allows one to give a simple necessary and sufficient criterion on the measure μ in order that I(μ) < ∞, and it also shows that I(μ) is continuous as a function of the coefficients of L in the sup-norm topology. In this paper, we first show that the same criterion for finiteness holds for non-reversible diffusions, and then show that I(μ) is locally Lipschitz continuous as a function of the coefficients of the generator L in the sup-norm topology. We then prove similar results in the setting of random evolutions.
A NOTE ON THE SMOLUCHOWSKI–KRAMERS APPROXIMATION FOR THE LANGEVIN EQUATION WITH REFLECTION
Authors: SPILIOPOULOS KONSTANTINOS
Published: July 2007

According to the Smoluchowski–Kramers approximation, the solution of the equation [Formula: see text] converges to the solution of the equation [Formula: see text] as μ → 0. We consider here a similar result for the Langevin process with elastic reflection on the boundary.
TIME SERIES FROM THE ORDINAL VIEWPOINT
Authors: KELLER KARSTEN , SINN MATHIEU , EMONDS JAN
Published: July 2007

Ordinal time series analysis is a new approach to the investigation of long and complex time series, which bases on ordinal patterns describing the order relations between the values of a time series. In this paper we consider ordinal time series analysis from the conceptional viewpoint. In particular, we introduce ordinal processes as models for ordinal time series analysis and discuss the structure of ordinal pattern distributions obtained from them. Special emphasis is on the relation of ordinal time series analysis to symbolic dynamics and to a transformation extracting the whole ordinal information contained in a time series. Finally, we consider invariance properties of ordinal time series analysis.
THE OPTIMAL PULSE HARVESTING POLICY ON A SINGLE-SPECIES POPULATION MODEL WITH BIRTH PULSES IN A POLLUTED ENVIRONMENT
Authors: LIU BING , TAO FENGMEI
Published: July 2007

We investigate the dynamics of a single-species model with birth pulses and pulse harvesting in a polluted environment. Using the discrete dynamical system determined by the stroboscopic map, we obtain an exact 1-period solution of the system whose birth function is a Ricker or Beverton–Holt function and obtain the threshold conditions for their stability. Further, we show the effects of the time of pulse harvesting on the maximum annual-sustainable yield. Our results show that the best time for harvesting is immediately after the birth pulses. Numerical simulation results also show that birth pulses and pulse harvesting make the single-species model in a polluted environment we consider more complex, and the system is dominated by periodic and chaotic solutions.
ANALYSIS OF PREFERENTIAL NETWORK MOTIF GENERATION IN AN ARTIFICIAL REGULATORY NETWORK MODEL CREATED BY DUPLICATION AND DIVERGENCE
Authors: LEIER ANDRÉ , KUO P. DWIGHT , BANZHAF WOLFGANG
Published: July 2007

Previous studies on network topology of artificial gene regulatory networks created by whole genome duplication and divergence processes show subgraph distributions similar to gene regulatory networks found in nature. In particular, certain network motifs are prominent in both types of networks. In this contribution, we analyze how duplication and divergence processes influence network topology and preferential generation of network motifs. We show that in the artificial model such preference originates from a stronger preservation of protein than regulatory sites by duplication and divergence. If these results can be transferred to regulatory networks in nature, we can infer that after duplication the paralogous transcription factor binding site is less likely to be preserved than the corresponding paralogous protein.
MODELING FLUCTUATIONS IN A MINIMAL PLANKTON MODEL: ROLE OF SPATIAL HETEROGENEITY AND STOCHASTICITY
Authors: BHATTACHARYYA R. , MUKHOPADHYAY B.
Published: July 2007

The present paper studies the naturally observed phenomenon of population fluctuation in the context of a minimal plankton model. The analysis of the basic model reveals asymptotic stable behavior that is unable to explain any kind of population outburst. We introduce the nonuniform spatial distribution of plankton by considering physical diffusion of the species concerned. The resulting reaction-diffusion equation model is first analyzed with constant diffusivity and then with variable diffusivity for the zooplankton. The model with variable diffusivity is analyzed by using Floquet theory. In both cases, the model is seen to exhibit stable behavior. Finally, we study another characteristic feature of any ecological population, namely, environmental fluctuations. We achieve this by perturbing the growth rate of phytoplankton and death rate of zooplankton by using colored noise. The resulting model is analyzed by evaluating the spectral density functions. It is observed that the stochastic model can generate a large fluctuation in population concentration for high amplitude driving forces.
COMPLEXITY OF AN IVLEV'S PREDATOR-PREY MODEL WITH PULSE
Authors: PANG GUOPING , CHEN LANSUN
Published: July 2007

In this paper, we investigate the extinction, permanence and dynamic complexity of the two-prey, one-predator system with Ivlev's functional response and impulsive perturbation on the predator at fixed moments. Conditions for the extinction and permanence of the system are established via the comparison theorem. Numerical simulations are carried out to explain the conclusions we obtain. Furthermore, the resulting bifurcation diagrams clearly show that the impulsive system takes on many forms of complexity including period-doubling bifurcation, period-halving bifurcation, and chaos.
EVALUATION OF A WAVELET BASED ASR FRONT-END
Authors: FAROOQ OMAR , DATTA SEKHARJIT
Published: July 2007

In this paper, we propose the use of the wavelet transform for the extraction of features for phonemes in order to overcome some of the shortcomings of short time Fourier transform. New log-energy based features are proposed using discrete wavelet transform as well as wavelet packets and their recognition performance has been evaluated. These features overcome the problem of shift variance as encountered in the features based on the discrete wavelet transform coefficients. The effect on the recognition performance by choosing different mother wavelets for the decomposition and window duration is also studied. Finally, a scheme based on the admissible wavelet packet has also been proposed and the results are discussed and compared with the frequently used Mel Frequency Cepstral Coefficients based features. The recognition performance of these features is further evaluated in the presence of different level of additive white Gaussian noise.
INHERENT VALUE SYSTEMS FOR AUTONOMOUS MENTAL DEVELOPMENT
Authors: HUANG XIAO , WENG JUYANG
Published: July 2007

The inherent value system of a developmental agent enables autonomous mental development to take place right after the agent's "birth." Biologically, it is not clear what basic components constitute a value system. In the computational model introduced here, we propose that inherent value systems should have at least three basic components: punishment, reward and novelty with decreasing weights from the first component to the last. Punishments and rewards are temporally sparse but novelty is temporally dense. We present a biologically inspired computational architecture that guides development of sensorimotor skills through real-time interactions with the environments, driven by an inborn value system. The inherent value system has been successfully tested on an artificial agent in a simulation environment and a robot in the real world.
COULD KNOWLEDGE-BASED NEURAL LEARNING BE USEFUL IN DEVELOPMENTAL ROBOTICS? THE CASE OF KBCC
Authors: SHULTZ THOMAS R. , RIVEST FRANÇOIS , EGRI LÁSZLÓ , THIVIERGE JEAN-PHILIPPE , DANDURAND FRÉDÉRIC
Published: July 2007

The new field of developmental robotics faces the formidable challenge of implementing effective learning mechanisms in complex, dynamic environments. We make a case that knowledge-based learning algorithms might help to meet this challenge. A constructive neural learning algorithm, knowledge-based cascade-correlation (KBCC), autonomously recruits previously-learned networks in addition to the single hidden units recruited by ordinary cascade-correlation. This enables learning by analogy when adequate prior knowledge is available, learning by induction from examples when there is no relevant prior knowledge, and various combinations of analogy and induction. A review of experiments with KBCC indicates that recruitment of relevant existing knowledge typically speeds learning and sometimes enables learning of otherwise impossible problems. Some additional domains of interest to developmental robotics are identified in which knowledge-based learning seems essential. The characteristics of KBCC in relation to other knowledge-based neural learners and analogical reasoning are summarized as is the neurological basis for learning from knowledge. Current limitations of this approach and directions for future work are discussed.
PITFALLS IN THE MODELING OF DEVELOPMENTAL SYSTEMS
Authors: SHIC FREDERICK , SCASSELLATI BRIAN
Published: July 2007

Computational models of development aim to describe the mechanisms that underlie the acquisition of new skills or the emergence of new capabilities. The strength of a model is judged by both its ability to explain the phenomena in question as well as its ability to generate new hypotheses, generalize to new situations, and provide a unifying conceptual framework. Although often constructed using traditional engineering methodologies, evaluating the performance of a computational model of development in terms of traditional perspectives is a flawed approach. This paper addresses the fundamental issues that confound quantitative analysis of computational models of developmental systems. In particular, we focus on the following recommendations: (i) do not equate the success of a developmental model with its peak performance at some task; (ii) do not employ purely subjective or vague measures of model fitness; and (iii) do not hide or reject variation as found in the computational model. Along the way, we discuss the aspects of computational models of development that lead to the requirements for specialized methods of analysis.
BODY IMAGE CONSTRUCTED FROM MOTOR AND TACTILE IMAGES WITH VISUAL INFORMATION
Authors: FUKE SAWA , OGINO MASAKI , ASADA MINORU
Published: July 2007

This paper proposes a learning model that enables a robot to acquire a body image for parts of its body that are invisible to itself. The model associates spatial perception based on motor experience and motor image with perception based on the activations of touch sensors and tactile image, both of which are supported by visual information. The tactile image can be acquired with the help of the motor image, which is thought to be the basis for spatial perception, because all spatial perceptions originate in motor experiences. Based on the proposed model, a robot estimates invisible hand positions using the Jacobian between the displacement of the joint angles and the optical flow of the hand. When the hand touches one of the invisible tactile sensor units on the face, the robot associates this sensor unit with the estimated hand position. The simulation results show that the spatial arrangement of tactile sensors is successfully acquired by the proposed model.
Contralateral Visual Hemifield Representations in the Human Pulvinar Nucleus
Authors: Cotton Philippa L. , Smith Andrew T.
Published: July 2007

The pulvinar is a major nucleus of the thalamus. Macaque pulvinar includes two subregions that are connected to the visual cortex and are retinotopically organized, but the organizing principles of the visual portions of the human pulvinar are unknown. We employed two tasks to address the question of whether human pulvinar exhibits spatial organization using event-related functional magnetic resonance imaging. The first was a global-motion discrimination with a rich visual stimulus and the second a luminance-discrimination task of similar difficulty that used a minimal visual stimulus. Both tasks required central fixation and covert peripheral attention. A group analysis of blood-oxygen-level-dependent responses elicited in the motion-discrimination task revealed activity bilaterally in the ventral pulvinar ( z = 2 in Talairach space). Clear position specificity was observed with activity elicited only by contralateral stimuli. Ipsilateral stimuli caused suppression. This locus of activity is distinct from the more dorsal ( z = 10) region of the pulvinar that has previously been reported to be visually responsive but not retinotopic. In the luminance-discrimination task, similar activity was seen, but it was weaker and detectable only in the left pulvinar. In additional experiments with no task, passively viewed global-motion stimuli also activated the ventral pulvinar bilaterally. Our results show for the first time a distinct, bilateral visual representation in human inferior pulvinar that appears to be contralaterally organized.
Correcting for the Sampling Bias Problem in Spike Train Information Measures
Authors: Panzeri Stefano , Senatore Riccardo , Montemurro Marcelo A. , Petersen Rasmus S.
Published: July 2007

Information Theory enables the quantification of how much information a neuronal response carries about external stimuli and is hence a natural analytic framework for studying neural coding. The main difficulty in its practical application to spike train analysis is that estimates of neuronal information from experimental data are prone to a systematic error (called “bias”). This bias is an inevitable consequence of the limited number of stimulus-response samples that it is possible to record in a real experiment. In this paper, we first explain the origin and the implications of the bias problem in spike train analysis. We then review and evaluate some recent general-purpose methods to correct for sampling bias: the Panzeri-Treves, Quadratic Extrapolation, Best Universal Bound, Nemenman-Shafee-Bialek procedures, and a recently proposed shuffling bias reduction procedure. Finally, we make practical recommendations for the accurate computation of information from spike trains. Our main recommendation is to estimate information using the shuffling bias reduction procedure in combination with one of the other four general purpose bias reduction procedures mentioned in the preceding text. This provides information estimates with acceptable variance and which are unbiased even when the number of trials per stimulus is as small as the number of possible discrete neuronal responses.
On the Aquedah in Modern Philosophy
Authors: Levy Ze'ev
Published: July 2007

The story of the Aquedah represents one of the most moving stories of the Bible. Most modern discussions on it take their point of departure from Soren Kierkegaard's Fear and Trembling. I shall do so too in this essay, which focuses on the relations between ethics and religious belief and tries to show that Kierkegaard misinterpreted the story. The inquiry analyzes philosophical responses to the Aquedah from Philo and Jewish and non-Jewish philosophers until the present. It underscores its paradoxical implications, including a structuralist analysis and comparison of the Aquedah with the biblical story of Yephta's daughter. The final conclusion asserts that what Kierkegaard extolled, Judaism condemns as sacrilege.
Dowry or Inheritance? Kinship, Property, And Women's Agency in Lisbon, Venice, and Florence (1572)
Authors: Sperling Jutta
Published: July 2007

The marital property regimes, inheritance practices, and kinship structures of Renaissance Italy and early modern Portugal were at opposite ends of a spectrum. In Italy, the legitimacy of marriage was defined as the outcome of dowry exchange governed by exclusio propter dotem, thus conceptually linked to the disinheritance of daughters and wives. In Portugal, where the Roman principle of equal inheritance was never abolished, domestic unions qualified as marriages insofar as joint ownership was established. Kinship structures were rigidly agnatic in Italy, but cognatic, even residually matrilineal, in Portugal. An investigation of notarial records from Lisbon, Venice, and Florence shows how women's capacity for full legal agency as property owners in both societies differed. Female legal agency, however, whether measured by women's capacity to engage in property transactions independently of their marital status (Portugal), or as the manipulation of limited legal resources, even resistance against a system of dispossession (Italy), always unfolded within the context of larger agendas that were beyond women's control, such as the processes of state formation in medieval Italy and empire-building in Portugal.
Intergenerational Exchanges in Mexico
Authors: Gomes Cristina
Published: July 2007

This article analyses exchanges of support between the elderly and adult generations and by gender, based on data from the United Nations household survey in Mexico City (SABE, 2000), and the National Study of Ageing and Health (ENASEM, 2001). Results indicate that in Mexico both generations — elderly parents and adult children — provide support, such as money, services, care or gifts for grandchildren, according to gender roles and the generation's resources. Men provide monetary support and reproduce their role as family providers, but this role depends on having an income from work and, in later years, a pension, a more common situation among men than among women. Women develop their female domestic role as caregivers. They do not have a formal income, but receive informal economic support and offer services and care to their relatives, reproducing their invisible and unpaid work during their life course. Both types of support are widely exchanged between elderly parents and adult children and children-in-law.
The Interlocking Trajectories between Negative Parenting Practices and Adolescent Depressive Symptoms
Authors: Wu Chyi-In
Published: July 2007

Previous studies have shown strong evidence of the association between negative parenting practices and adolescents' depressive symptoms. However, most of these findings are based on cross-sectional data, which can only detect the association from a static perspective. They are not able to detect the dynamic relationship between parents' harsh parenting and adolescents' depressive symptoms. The interlocking trajectories between negative parenting practices and adolescent depressive symptoms may serve as the core of a theoretical framework that can better capture the origins of adolescents' behavioural development. This article incorporates a life course perspective to discuss how mothers' negative parenting practices and depressive symptoms among the adolescent generation interlink. Using data from a panel design longitudinal study across a three-year period, and employing latent growth curve (LGC) analysis, which was used to estimate trajectories of change in adolescents' depressive symptoms and their mothers' harsh parenting, this study traces the links between negative parenting practices and adolescents' depressive symptoms in a dynamic manner. In general, the findings of this study support the hypothesis that there is an interlocking relationship between mothers' negative parenting practices and adolescents' depressive symptoms.
The `Intergenerational Stake Hypothesis' in Indonesia and Germany
Authors: Trommsdorff Gisela , Schwarz Beate
Published: July 2007

The aim of this study is to test the general hypothesis that parents and their children systematically differ with respect to the perception of their relationship as described by the literature on the `intergenerational stake'. To this end, the study compared 100 dyads of adult daughters and elderly mothers from Indonesia and Germany. Mothers and daughters were interviewed with respect to their value orientations and their evaluation of the present mother—daughter relationship. The results demonstrated that the `intergenerational stake' hypothesis could be replicated for different aspects of the relationship quality in the German sample as compared to the Indonesian sample. Besides a pattern of mother— daughter differences consistent with the `intergenerational stake hypothesis', two groups with different patterns were found: one group in which daughters perceived the relationship as more positive than mothers and another group characterized by low maternal self-disclosure. Culture and mothers' collectivism were associated with the assignment to the latter group. The results are interpreted in a culture-informed theoretical framework of intergenerational relations.
Hierarchical Analysis of Woven Composite DCB Specimen
Authors: Varghese Julian , Whitcomb John , Goyal Deepak , Dong Tang Xiao
Published: July 2007

A new strategy has been introduced by an earlier work where the natural hierarchical character of model descriptions and simulation results are exploited to expedite analysis of problems. Hierarchical techniques are used in the development, organization, and management of finite element models, and for the post-processing of the results from the analyses. In the current work, the hierarchical strategy is used to analyze materials that have a complex microstructure. The hierarchical analysis environment is used to analyze a double cantilever beam (DCB) specimen fabricated with woven composite. Such a configuration contains many microstructural scales such as fiber/matrix, tow architecture, and laminate. The results of a detailed finite element stress analysis on the DCB specimen are presented. The strain energy release rate along the width of the crack front is calculated and is found to be dependent on the local microstructure at the crack front.
Failure Map of Composite Laminate Mechanical Joint
Authors: Valenza A. , Fiore V. , Borsellino C. , Calabrese L. , Di Bella G.
Published: July 2007

The aim of this research is to investigate the pin/hole contact stress of a composite laminate and failure modes when submitted to tensile bearing tests. The limit loads and failure modes are evaluated as a function of pin diameter and hole position. Analyzing the joint geometry effect on the fracture mechanisms, a failure map is obtained, identifying three regions of typical failure modes of mechanically fastened joints. A theoretical approach is proposed to identify the field of each fracture mode to obtain a simple experimental methodology to support the design of a particular joint laminate. In addition, a simplified numerical model is proposed to evaluate near the hole the stress/strain distribution under tensile bearing load. This allows one to better understand the relevant dependence of the failure modes from the geometry of the joint for a given composite laminate.
Reinforcing Porous Silica with Carbon Nanotubes to Enhance Mechanical Performance
Authors: Luo Jen-Tsung , Wen Hua-Chiang , Chou Chang-Pin , Wu Wen-Fa , Wan Ben-Zu
Published: July 2007

In this study, porous silica (SiO2) film is reinforced with carbon nanotubes (CNTs), which gets homogeneously dispersed in porous SiO 2 gel by ultrasonic stirring. The size of SiO2 molecules is the same as that of nanotubes, so a fine CNTs/SiO2 network is formed. Nanoindenters used to test the mechanical properties of the resulting specimens show a marked enhancement in the properties as a function of filler content. Interfacial bonding and the distribution of CNTs also strongly affected the mechanical performance. Although a high concentration of CNTs improves the mechanical characteristics of the matrix, it also causes agglomeration such that the mechanical performance at the surface was disproportionate. Fourier transform infrared spectroscopy (FTIR) analysis indicates that there is little chemical reaction occurring between CNTs and SiO2. The results suggest that CNTs are ineffective reinforcements.
A Thermal Analysis Approach for the Detection of Damage in Carbon—Carbon Type Composite
Authors: Coutin Sandra , Chaves Arlex , Just Frederick
Published: July 2007

This research work focuses on the viability of applying a thermal method for detecting damage in carbon fiber and sandwich composites. The fundamental of the technique analyzed herein is based on changes in the temperature profiles as a heat flux travels through the material. A 3-D finite element simulation provides good qualitative results and an inexpensive tool for detecting the presence of damage and its exact location. The influence of parameters, such as damage depth, diameter, and limiting detection time is also studied. This thermal technique is also implemented experimentally in an attempt to detect damage. Experimental results are compared to the numerical simulations in terms of damage locations and temperature trends. Damage is detected experimentally for metal surfaces and carbon fiber composite materials with simple structural arrays. However, for honeycomb composite materials, the detection of damage from the thermal standpoint was somewhat difficult due to the complex temperature profile generated within the material, due to its complex array of materials.
Fabrication of Graphite Nanofibers Reinforced Metal Matrix Composites by Powder Metallurgy and Their Mechanical and Physical Characteristics
Authors: Jang J.H. , Han K.S.
Published: July 2007

Aluminum metal matrix composites reinforced by graphite nanofibers (GNFs) are fabricated by conventional powder metallurgy methods, and their mechanical and physical characteristics are investigated. Mixing conditions are established by microhardness tests and microscopy observations. The GNF-Al composites are consolidated by hot isostatic pressing (HIP); a high density of composites can be achieved. From microhardness and compression tests, the optimal nanofiber content is determined. The physical properties of the GNF-Al composites are measured by thermal and electrical transport tests. The results indicate that the addition of nanofibers improves the thermal conductivity and the electrical resistivity, but the dimensional stability under high temperatures is not improved. This study may provide experimental information in the design and fabrication of functional metal matrix nanocomposites.
3D Multi Delamination/Fracture Analysis of Composites Subjected to Impact Loadings
Authors: Mohammadi S. , Moosavi Khandan A.A.
Published: July 2007

This paper presents a combined finite/discrete element method for 2D/3D modeling of composite specimens subjected to dynamic/impact loadings. Simulation of various composite failure modes, such as delamination and layer cracking, requires a sophisticated numerical approach capable of handling anisotropic behavior of individual layers as well as potential interaction phenomena. The combined finite/discrete element (FE/DE) methodology has proved to be an efficient approach for the simulation of progressive fracture in brittle and quasi-brittle media. Therefore, an existing FE/DE approach has been adopted and modified in this study for the simulation of delamination and fracture in composites subjected to impact loadings. The paper comprises a section on fundamental aspects of adopted FE/DE algorithm and discusses the basics of a general node to face nonlinear frictional contact algorithm. It is followed by details of formulation for composite failure mechanisms, including the Hoffman material model and the 3D Hashin interface model. Several numerical simulations are then discussed to assess the performance of the proposed approach. Full progressive fracture and fragmentation behavior as well as potential post-cracking interactions caused by the newly created crack sides and segments are automatically controlled. The same procedure is capable of modeling the application of fiber reinforced polymer (FRP) layers to other engineering structures in order to improve their flexible behavior in static and dynamic loading conditions.
The Study of Obliquity on the Ballistic Performance of Basket Fabric Composite Materials
Authors: Chu C.K. , Chen Y.L. , Hseu G.C. , Hwang D.G.
Published: July 2007

The main purpose of this study is to investigate the ballistic resistance behavior of basket 2 × 2 fabric aramid laminate composite materials experiencing oblique impact. The ballistic resistance performance at normal impact is discussed widely in most reports. However, the reports concerning ballistic resistance behavior at oblique impact are limited in metal material. The research of the oblique ballistic behavior of fabrics composites is rarely to be seen. The ballistic results show that the degree of ricochet of aramid laminates is greater than metal (>75° or even more). The offset direction when a projectile perforates the laminate is converse with those of metal plates. Both sliding and embedding behaviors were found in the laminate after impact. So, the possibility that a basket weave causes a ricochet will be less than that of a plain weave.
Resistance Heating for Self-healing Composites
Authors: Kwok Nathan , Hahn H. Thomas
Published: July 2007

Thermally remendable polymers have recently become available that are paving the way for the creation of self-healing composites. This article investigates the use of carbon fibers as a resistive heating network for future use in a self-healing composite. Various electrode methods are studied in an attempt to reduce the contact resistance that causes localized heating around the electrode. In addition to localized heating, electrical conduction through the fibers creates heat through composite resistance. It was observed that for short distances between electrodes, contact resistance dominates while over longer distances, composite resistance dominates. The balance between the two types of heating is measured and modeled using finite element modeling (FEM).
Torrey Canyon: The Political Dimension
Authors: Sheail John
Published: July 2007

It is forty years since the Torrey Canyon oil-tanker disaster of March/April 1967. The unprecedented scale of the pollution and its impact on the Cornish coast is commonly perceived as an important trigger to the environmental movement of the 1970s. The article focuses on the political response to the immediate stranding and destruction of the tanker, the pollution of the beaches, the legal and scientific advice tendered, and the longer-term repercussions for ‘the machinery of government’. If not a trigger, such exposure to public criticism accelerated the incremental pace by which ministers and their officials responded to the increasing significance being given to pollution issues.
Fascism and Catholicism: A Case Study of the Sacrario dei Caduti Fascisti in the Crypt of San Domenico, Siena
Authors: Parsons Gerald
Published: July 2007

By means of a detailed and specific case-study, this article contributes to the history of the relationship between catholicism and fascism in Italy. After noting the profound ambiguity that was characteristic of relations between the church and the regime — not least because of the tendency for fascism to present itself in religious terms, especially in relation to the memorialization of its dead — the article takes up a recent suggestion that the cooperation between catholicism and fascism in Siena in the mid 1930s constituted a textbook example of the wider consensus between church and regime in Italy in this period. It does so by analysing the origins and official inauguration of the Sienese Sacrario dei Caduti Fascisti located in the crypt of the church of San Domenico. It argues that the latter event, in November 1938, amounted to a moment of de facto syncretism. Finally, the article reflects on the subsequent history of the crypt and the way in which the sacrario has been relegated to the margins of Sienese memory and historical recollection.
Hans Rothfels — An Intellectual Biography in the Age of Extremes
Authors: Eckel Jan
Published: July 2007

Hans Rothfels was one of the most influential historians in the early Federal Republic of Germany. Recently, a controversy has been sparked off among German historians about his political attitude towards National Socialism. The article argues that the focus of this debate is too narrow and that an examination of Rothfels’ intellectual biography can give an insight into more general historical problems and contexts: long-term intellectual continuities and transformations of German historiography, the determinants of scholarlyscientific production, and the intellectual functions of historiographical operations and interpretations. Covering the whole career of Rothfels from the 1920s through to the 1960s, the article first analyses the way in which Rothfels’ histororiography was shaped by the social and institutional conditions of his academic work. In a second step, it shows that, at its core, his historiography was a way of reflecting about contemporary events and developments. In the different stages of his academic life, Rothfels developed distinct interpretations of German history that were an attempt to give meaning to situations he had observed or lived through himself. Finally, the text examines how important biographical experiences and perceptions influenced the scholarly production of the historian.
The Constitution of Organizational Legitimacy: A Narrative Perspective
Authors: Golant Benjamin D. , Sillince John A.A.
Published: July 2007

This article recognizes a major dichotomy in the study of legitimacy construction at the organizational level. Scholars have either focused on agent-centred explanations of organizational legitimation, which favour its evaluative dimension, or on structural explanations, which highlight the isomorphic pressures imposed on individual organizations in order to become and remain intelligible to stakeholders. By applying a discursive methodology, we propose a new approach for the study of organizational legitimacy construction that incorporates both its evaluative and cognitive dimensions. Drawing on a structurational model of narrative recursivity, inspired by Greimas (1987), we argue that the construction of organizational legitimacy is dependent on both the persuasiveness of organizational storytelling and on the realization of a taken-for-granted narrative structure. We explicate the processes by which legitimacy is narratively constructed through empirical data associated with the founding of an HIV/AIDS organization.
Preservation and Dissolution of the Target Firm's Embedded Ties in Acquisitions
Authors: Spedale Simona , Van Den Bosch Frans A. J. , Volberda Henk W.
Published: July 2007

Our study builds on extant theory on embeddedness by concentrating on the process of preservation and dissolution of the target firm's embedded ties in acquisitions. We identify four critical areas (communication, idiosyncratic investments, interpersonal relations and personnel turnover) where managerial decisions taken during the acquisition process affect the components of the target firm's embedded ties — trust, joint problem-solving, conflict resolution and exchange of fine-grained information. The preservation or dissolution of an embedded tie depends ultimately on two specific tie contingencies, the balance of power between the target firm and the embedded relation and interpretive processes at the interface between the two. Our findings have implications for the study of the dissolution of market ties by pointing to different roles played by social and institutional forces, power asymmetries and competition in the dynamics of embedded ties. Finally, we encourage theory development in acquisition studies by positing the importance of interpretive processes and, more broadly, relational elements that span the boundaries of the parent—target dyad.
Understanding Governance: Ten Years On
Authors: Rhodes R.A.W.
Published: July 2007

The paper reassesses the argument in Understanding Governance (1997). The first section summarizes where we are now in the study of governance, reviewing briefly the key concepts of policy networks, governance, core executive, hollowing out the state and the differentiated polity. The second section engages with my critics with the aim of opening new directions of research. I concentrate on the key issues of: the context of policy networks, explaining change and the role of ideas, the decline of the state, rescuing the core executive, and steering networks. Under each heading, I sketch a decentred answer to the question of where we go from here. I argue the analysis of governance should focus on beliefs, practices, traditions and dilemmas.
Return to work after major trauma
Authors: Holtslag Herman R , Post Marcel W , van der Werken Chris , Lindeman Eline
Published: July 2007

Objective : To quantify the prevalence of return to work after major trauma, and to investigate the determinants of postinjury work status.

Design : Prospective cohort study.

Setting : University Medical Centre Utrecht, a level 1 trauma centre in the Netherlands.

Method : All severely injured (ISS > 16) adult (age = 16 +) trauma survivors admitted from January 1999 to December 2000 who were full-time employed at the time of the injury were selected for follow-up (n = 214). Response rate was 93%. Outcome was assessed at a mean of 15 months (SD = 1.5) after injury. Multivariate logistic regression analyses identified determinants at hospital discharge and at follow-up.

Results : Following injury 58.4% of the patients (n = 125) were able to return to full-time employment, 21.5% had a part-time job, and 20.1% did not return to work. Univariate analysis yielded the following significant determinants of postinjury work status: age, comorbidity, injury severity score, brain injury, spinal cord injury, length of stay in an intensive care unit, hospital stay, discharge destination, percentage of permanent impairment (according to the fourth American Medical Association guide (AMA)), limitations in activities of daily living and cognitive complaints. Logistic regression analyses (23% explained variance) identified spinal cord injury, duration of hospital stay, discharge destination and age as determinants of return to work at hospital discharge. At follow-up, determinants of return to work included AMA, activities of daily living, cognitive complaints and being discharged home (51% explained variance).

Conclusions : Around 60% of the patients returned to their pre-injury work status after major trauma. The return to work rate was only partly explained by disability at follow-up. Independent determinants of return to work differ with the time of assessment.