bluuebunny/crossref_metadata_2025 huggingface dataset:
The Dominance of Behavioural Activation over Behavioural Inhibition in Conduct Disordered Boys with or without Attention Deficit Hyperactivity Disorder
Authors: Matthys Walter , Goozen Stephanie H. M. van , Vries Han de , Cohen‐Kettenis Peggy T. , Engeland Herman van
Published: July 2003

On the basis of Gray's theory, Quay suggested that conduct disorder (CD) is associated with a Behavioural Activation System (BAS) that dominates over the Behavioural Inhibition System (BIS), whereas attention deficit hyperactivity disorder (ADHD) is characterised by an underactive BIS. Two studies were conducted to test the hypothesis that the dominance of the BAS over the BIS is more pronounced in CD comorbid with ADHD (CD/ADHD) than in CD alone. First of all, a response perseveration task was used, i.e. the door‐opening task (Daugherty & Quay, 1991). In this game, the subject chooses either to open the next door or to stop playing; there is a steadily increasing ratio of punished responses to rewarded responses and a large number of doors opened is indicative of response perseveration. As expected, a steady increase in the number of doors opened was found across normal control (NC) boys, CD boys, and CD/ADHD boys (NC < CD < CD/ADHD). Second, the dominance of the BAS over the BIS was examined by observing the social behaviour of the child in interaction with a research assistant who alternately activated the BAS and the BIS while a game was played. The behaviour of the children was analysed according to ethological methods. Group differences in the frequencies of three out of five behavioural categories were in line with the results of the door‐opening task (NC < CD < CD/ADHD).
The Effects of Primary Division, Student‐mediated Conflict Resolution Programs on Playground Aggression
Authors: Cunningham Charles E. , Cunningham Lesley J. , Martorelli Vince , Tran Ann , Young Julie , Zacharias Rose
Published: July 2003

This study examined the effects of a student‐mediated conflict resolution program on primary school (junior kindergarten to grade 5) playground aggression. Mediation teams of grade 5 students (approximately age 10) participated in 15 hours of training according to the model developed by Cunningham, Cunningham, and Martorelli (1997). Following baseline observations, mediation was introduced onto the playgrounds of three schools according to a multiple baseline design. Mediators successfully resolved approximately 90% of the playground conflicts in which they intervened. Direct observations suggest that the student mediation program reduced physically aggressive playground behavior by 51% to 65%. These effects were sustained at 1‐year follow‐up observations. Teacher and mediator satisfaction questionnaires provided strong support for impact, feasibility, and acceptability of this program.
Peer Relationship Problems in Children with Tourette's Disorder or Diabetes Mellitus
Authors: Bawden Harry N. , Stokes Aidan , Carol S. Carol S. , Camfield Peter R. , Salisbury Sonia
Published: July 2003

Peer relationships, social skills, self‐esteem, parental psychopathology, and family functioning of children with Tourette's disorder and a chronic disease control group of children with diabetes mellitus were compared. Children with Tourette's disorder had poorer peer relationships than their classmates and were more likely to have extreme scores reflecting increased risk for peer relationship problems than children with diabetes mellitus, but did not report self‐esteem problems or social skills deficits. Measures of peer relationships were not related to severity or duration of tics. Children with Tourette's disorder and Attention Deficit Hyperactivity Disorder were at increased risk for poor peer relationships. The psychosocial problems of children with Tourette's disorder do not appear to be the generic result of having a chronic disease.
Discrepancies between Mothers' and Fathers' Perceptions of Sons' and Daughters' Problem Behaviour: A Longitudinal Analysis of Parent‐Adolescent Agreement on Internalising and Externalising Problem Behaviour
Authors: Seiffge‐Krenke Inge , Kollmar Frank
Published: July 2003

One hundred and ninety‐eight adolescents and their mothers (N= 189) and fathers (N= 136) participated in a 4‐year longitudinal study. Adolescent problem behaviour was assessed by the Youth Self‐Report (YSR) and the Child Behavior Checklist (CBCL). In addition, parental stress and marital adjustment were determined.

Results showed that mothers and fathers showed high agreement, especially about their daughters, whereas parents and adolescents showed little agreement. Agreement was higher for internalising than for externalising behaviours. In general, adolescents reported more symptomatology than their parents did. However, mothers' ratings of their children's behaviours were significantly correlated with adolescents' self‐ratings, but fathers' ratings were not. Statistical tests of correlations showed that mothers experiencing stress caused by marital problems perceived more problem behaviours in their children. Fathers' perceptions were relatively unaffected by personal adjustment. However, poor marital adjustment perceived by both parents showed a significant negative relation to adolescent externalising problem behaviour.
Modelling the Training Effects of Kinaesthetic Acuity Measurement in Children
Authors: Sims K. , Morton J.
Published: July 2003

In previous papers (Sims, Henderson, Hulme, & Morton, 1996a; Sims, Henderson, Morton, & Hulme, 1996b) we have found that the motor skills of clumsy children are capable of significant improvement following relatively brief interventions. Most remarkably, this included a 10‐minute intervention while testing the kinaesthetic acuity of the children using a staircase method (Pest). In this paper, we show that Pest testing improves the kinaesthetic acuity of normal children as well. We analyse the available data on the development and improvement of motor skills and kinaesthetic acuity and derive a causal model for the underlying skills. We show that at least three independent cognitive/biological components are required to account for the data. These three components are affected differently by the various interventions that have been tried. We deduce that improvement on a general test of motor impairment can be found as a result of training in kinaesthetic acuity or through other, independent factors.
The Frequency and Distribution of Spontaneous Attention Shifts between Social and Nonsocial Stimuli in Autistic, Typically Developing, and Nonautistic Developmentally Delayed Infants
Authors: Swettenham J. , Baron‐Cohen S. , Charman T. , Cox A. , Baird G. , Drew A. , Rees L. , Wheelwright S.
Published: July 2003

Spontaneous shifts of attention were observed in autistic, typically developing, and nonautistic developmentally delayed infants. Three types of attention shifting behaviour were observed; (1) between an object and another object, (2) between an object and a person, and (3) between a person and another person. The two control groups shifted attention more frequently between an object and a person than between an object and another object or between a person and another person. The infants with autism showed a different pattern, shifting attention between an object and another object more than any other type of shift. Furthermore, infants with autism showed fewer shifts of attention between an object and a person, and between person and person, than did the two control groups. They also spent less time overall looking at people and looked more briefly at people and for longer durations at objects, compared to the two control groups. These results indicate an abnormality in social orientation in autism even at the early age of 20 months.
Enhanced Discrimination of Novel, Highly Similar Stimuli by Adults with Autism During a Perceptual Learning Task
Authors: Plaisted Kate , O'Riordan Michelle , Baron‐Cohen Simon
Published: July 2003

High‐functioning adults with autism and control adults were tested on a perceptual learning task that compared discrimination performance on familiar and novel stimuli. Control adults were better able to discriminate familiar than novel stimuli‐the perceptual learning effect. No perceptual learning effect was observed in adults with autism although they discriminated the novel stimuli significantly better than control adults. This enhanced discrimination learning about novel, but not familiar, stimuli in autism is discussed in relation to two current hypotheses of information processing in autism‐weak central coherence and reduced attention‐switching‐and a new third hypothesis, which suggests that features held in common between stimuli are processed poorly and features unique to a stimulus are processed well in autism.
Enhanced Visual Search for a Conjunctive Target in Autism: A Research Note
Authors: Plaisted Kate , O'Riordan Michelle , Baron‐Cohen Simon
Published: July 2003

Children with and without autism were compared on two visual search tasks in which a letter target appeared among two sets of letter distracters. In one task, the target shared colour with one set of distracters but was unique in shape‐the feature search task. In the other, the conjunctive search task, the target shared colour with one set and shape with another set of distracters. Although search was slower in the conjunctive task than the feature task in normally developing control children, children with autism showed no significant slowing in reaction time in the conjunctive task and were faster than control children in this task. This result is discussed in the light of theories of visual search which state that rate of search is determined by the degree of similarity between target and distracters.
Relationship between Sleep and Temperament Revisited: Evidence for 12‐month‐olds: A Research Note
Authors: Scher Anat , Tirosh Emanuel , Lavie Peretz
Published: July 2003

This study measured the sleep attributes of 30 normal 12‐month‐old children with a computerized movement detector (Actigraph). Data on the child's temperament was based on the Carey Toddler Temperament Questionnaire, which the mother completed. The main finding was that rhythmic children went to sleep earlier and had longer sleep duration; however, their sleep pattern was not more efficient compared to children with irregular rhythmicity. The results of the present study provide only limited evidence to the association between the regulation of sleep‐wake cycles and the temperamental characteristics of the child. Hence it may be concluded that within non‐referred low‐risk infants, temperament does not discriminate between good and poor sleepers. Alternatively, however, the marginal relationship between sleep and temperament demonstrated in the present study may reflect the limitation of maternal perception as a source for temperament assessment.
Being Canadian
Authors: Kymlicka Will
Published: July 2003

This article is one of a series commissioned byGovernment and Oppositionexploring identity politics in several national and international contexts. Most discussions of ‘the Canadian identity’ focus on how ‘being Canadian’ relates to various sub-state group identities, such as Québécois, Aboriginal or immigrant identities. There is often said to be a distinctly Canadian model of reconciling national identity with sub-group identities. I argue that the Canadian model of accommodating identities is not unique, but rather reflects broader trends throughout the West. I also suggest that an equally important but neglected part of ‘being Canadian’ is the external dimension i.e., how Canadians relate to the wides world.
On Natural Convective Heat Transfer in Vertical Channels With a Single Surface Mounted Heat-Flux Module
Authors: Desrayaud G. , Fichera A.
Published: July 2003

This paper presents the numerical predictions of heat transfer and fluid flow characteristics for natural convection in a vertical channel with two-dimensional protruding heat-flux module as applied to the cooling of electronic components. The investigation is for a configuration consisting of a single module mounted on a vertical adiabatic wall. An attempt was made to combine the temperature of the module for all the dimensions of the module into a single composite correlation, along with the numerical data.
Evaporation Heat Transfer in Sintered Porous Media
Authors: Hanlon M. A. , Ma H. B.
Published: July 2003

A two-dimensional model is presented to predict the overall heat transfer capability for a sintered wick structure. The model considers the absence of bulk fluid at the top surface of the wick, heat conduction resistance through the wick, capillary limitation, and the onset of nucleate boiling. The numerical results show that thin film evaporation occurring only at the top surface of a wick plays an important role in the enhancement of evaporating heat transfer and depends on the thin film evaporation, the particle size, the porosity, and the wick structure thickness. By decreasing the average particle radius, the evaporation heat transfer coefficient can be enhanced. Additionally, there exists an optimum characteristic thickness for maximum heat removal. The maximum superheat allowable for thin film evaporation at the top surface of a wick is presented to be a function of the particle radius, wick porosity, wick structure thickness, and effective thermal conductivity. In order to verify the theoretical analysis, an experimental system was established, and a comparison with the theoretical prediction conducted. Results of the investigation will assist in optimizing the heat transfer performance of sintered porous media in heat pipes and better understanding of thin film evaporation.
Effect of Fin Geometry on Condensation of R407C in a Staggered Bundle of Horizontal Finned Tubes
Authors: Honda H. , Takata N. , Takamatsu H. , Kim J. S. , Usami K.
Published: July 2003

Experimental results are presented that show the effect of fin geometry on condensation of downward flowing zeotropic refrigerant mixture R407C in a staggered bundle of horizontal finned tubes. Two types of conventional low-fin tubes and three types of three-dimensional-fin tubes were tested. The refrigerant mass velocity ranged from 4 to 23 kg/m2 s and the condensation temperature difference from 3 to 12 K. The measured condensation heat transfer coefficient was lower than the previous results for R134a, with the difference being more significant for smaller mass velocity. The effect of fin geometry on the condensation heat transfer coefficient was less significant for R407C than for R134a. The effect of condensate inundation was more significant for the three-dimensional-fin tubes than for the low-fin tubes. By using the dimensionless heat transfer correlation for the condensate film that was based on the experimental data for R134a, a superficial vapor-phase heat transfer coefficient was obtained for condensation of R407C. The vapor-phase heat transfer coefficient showed characteristics similar to the vapor-phase mass transfer coefficient that was obtained in the previous study for R123/R134a.
The Synthetic Kernel (SKN) Method Applied to Thermal Radiative Transfer in Absorbing, Emitting, and Isotropically Scattering Homogeneous and Inhomogeneous Solid Spherical Medium
Authors: Altac¸ Zekeriya , Tekkalmaz Mesut
Published: July 2003

The SKN method is proposed for solving radiative transfer problems in solid spherical participating medium. The method relies on approximating the integral transfer kernels by a sum of synthetic kernels. Then the transfer equation is reducible to a set of N-coupled second-order differential equations. The method is benchmarked against the exact and the discrete-ordinates method solutions for various optical radius and scattering albedos. Spatially varying scattering albedos are used to test the performance of the method in inhomogeneous media. Three quadrature sets are proposed for use with this method, and their convergence to the exact solution is investigated. It is demonstrated that the SKN method possess the capability of solving radiative transfer problems yielding excellent solutions in solid spherical media.
Effects of Radiative Transfer Modeling on Transient Temperature Distribution in Semitransparent Glass Rod
Authors: Wei Zhiyong , Lee Kok-Meng , Tchikanda Serge W. , Zhou Zhi , Hong Siu-Ping
Published: July 2003

This paper presents a method of modeling the radiative energy transfer that takes place during the transient of joining two concentric, semitransparent glass cylinders. Specifically, we predict the two-dimensional transient temperature and heat flux distributions to a ramp input which advances the cylinders into a furnace at high temperature. In this paper, we discretize the fully conservative form of two-dimensional Radiative Transfer Equation (RTE) in both curvilinear and cylindrical coordinate systems so that it can be used for arbitrary axisymmetric cylindrical geometry. We compute the transient temperature field using both the Discrete Ordinate Method (DOM) and the widely used Rosseland’s approximation. The comparison shows that Rosseland’s approximation fails badly near the gap inside the glass media and when the radiative heat flux is dominant at short wavelengths where the spectral absorption coefficient is relatively small. Most prior studies of optical fiber drawing processes at the melting point (generally used Myers’ two-step band model at room temperature) neglect the effects of the spectral absorption coefficient at short wavelengths λ<3μm. In this study, we suggest a modified band model that includes the glass absorption coefficient in the short-wavelength band. Our results show that although the spectral absorption coefficient at short wavelengths is relatively small, its effects on the temperature and heat flux are considerable.
Monte Carlo Simulation of Radiative Heat Transfer in Coarse Fibrous Media
Authors: Nisipeanu Eugen , Jones Peter D.
Published: July 2003

Direct Geometric Monte Carlo modeling of a fibrous medium is undertaken. The medium is represented as a monodisperse array, with known solidity, of randomly oriented cylinders of known index of refraction. This technique has the advantage that further radiative properties of the medium (absorption coefficient, scattering albedo, scattering phase function) are not required, and the drawback that its’ Snell- and Fresnel-generated dynamics suggest a limitation to large, smooth fibers. It is found that radiative heat flux results are highly dependent on bias in the polar orientation angle (relative to the boundary planes) of the fibers. Randomly oriented fiber results compare well to both the large (specular radiosity method) and small (radiative transfer equation) limits, while the results of previous experiments lie within the range of simulation results generated using varying degrees of orientation bias.
Dual Pulsating or Steady Slot Jet Cooling of a Constant Heat Flux Surface
Authors: Chaniotis A. K. , Poulikakos D. , Ventikos Y.
Published: July 2003

The work presented in this paper focuses on the effect of jet pulsation on the heat transfer and fluid dynamics characteristics of single and double jet impingement on a constant heat flux heated surface. Specifically, the influence of frequency, amplitude and in particular, of the phase difference of the two jets on the temperature distribution of the heated surface is examined. The simulations are conducted using a novel, remeshed Smooth Particle Hydrodynamics (SPH) methodology that is based on particle discretization of the governing compressible Navier-Stokes equations. It was found that the strong aerodynamic and thermal interaction that exists between the gaseous jets and the impingement surface leads to non-linear system responses; with serious heat transfer implications. Dynamical systems analysis leads to the identification of intermittent periodic/chaotic behavior above a threshold value of the Reynolds number. As a result, a reduction in the maximum plate temperature in a window of periodic behavior was discovered.
Bubble Nucleation on Micro Line Heaters
Authors: Lee Jung-Yeop , Park Hong-Chul , Jung Jung-Yeul , Kwak Ho-Young
Published: July 2003

Nucleation temperatures on micro line heaters were measured precisely by obtaining the I-R (current-resistance) characteristic curves of the heaters. The bubble nucleation temperature on the heater with 3 μm width is higher than the superheat limit, while the temperature on the heater with broader width of 5 μm is considerably less than the superheat limit. The nucleation temperatures were also estimated by using the molecular cluster model for bubble nucleation on the cavity free surface with effect of contact angle. The bubble nucleation process was observed by microscope/35 mm camera unit with a flash light of μs duration.
Spatial and Temporal Stabilities of Flow in a Natural Circulation Loop: Influences of Thermal Boundary Condition
Authors: Jiang Y. Y. , Shoji M.
Published: July 2003

In a natural circular loop, the thermal convection demonstrates various spatial patterns and temporal instabilities. Problem consists in determining them with respects to thermal boundary conditions. To this end a multiple scales analysis is applied which resembles the inherent characteristic of the pattern formation in the Rayleigh-Be´nard convection. A three-dimensional nonlinear model is proposed by incorporating the flow modes derived along the analysis. The differences of thermal boundary condition are reflected by a coefficient δ. For small δ, numerical solution to the model shows that only temporal instability exists and Lorenz chaos is possible, otherwise, for large values both spatial and temporal instabilities occur leading to cellular flow and intermittency chaos. The model predicted some additional phenomena opening for experimental observation. It seems significant that this study proposes an algorithm for the control of flow stability and distribution by varying the thermal boundary condition.
An Improved Numerical Study of the Wall Effect on Hot-Wire Measurements
Authors: Shi Jun-Mei , Breuer Michael , Durst Franz , Scha¨fer Michael
Published: July 2003

Numerical investigations of the heat transfer from hot wires in near-wall measurements were carried out. Special attention was paid to the effect of the wall thickness, the flow conditions below the wall and the shear velocity connected to different wall materials. Compared with previous studies, an improved physical model taking into account the flow region below the wall in the computational domain was applied. The results obtained agree well with experimental data in the literature for walls consisting of both highly and poorly conducting materials. The investigation showed that the shear velocity Uτ has a significant influence on hot-wire measurements in the vicinity of a wall. Nevertheless, discernible effects of the wall thickness and the flow condition below the wall were found only in the case of a poorly conducting wall. In addition, the results also suggest a weak effect of the overheat ratio for a wire with an infinitely large aspect ratio.
Heat Transfer Coefficients on the Squealer Tip and Near Squealer Tip Regions of a Gas Turbine Blade
Authors: Kwak Jae Su , Han Je-Chin
Published: July 2003

Detailed heat transfer coefficient distributions on a squealer tip of a gas turbine blade were measured using a hue detection based transient liquid crystals technique. The heat transfer coefficients on the shroud and near tip regions of the pressure and suction sides of a blade were also measured. Tests were performed on a five-bladed linear cascade with a blow-down facility. The blade was a two-dimensional model of a first stage gas turbine rotor blade with a profile of a GE-E3 aircraft gas turbine engine rotor blade. The Reynolds number based on the cascade exit velocity and axial chord length of a blade was 1.1×106 and the total turning angle of the blade was 97.7 deg. The overall pressure ratio was 1.2 and the inlet and exit Mach number were 0.25 and 0.59, respectively. The turbulence intensity level at the cascade inlet was 9.7 percent. The heat transfer measurements were taken at the three different tip gap clearances of 1.0 percent, 1.5 percent, and 2.5 percent of blade span. Results showed that the overall heat transfer coefficients on the squealer tip were higher than that on the shroud surface and the near tip regions of the pressure and suction sides. Results also showed that the heat transfer coefficients on the squealer tip and its shroud were lower than that on the plane tip and shroud. However, the reductions of heat transfer coefficients near the tip regions of the pressure and suction sides were not remarkable.
Unified Wilson Plot Method for Determining Heat Transfer Correlations for Heat Exchangers
Authors: Styrylska Teresa B. , Lechowska Agnieszka A.
Published: July 2003

The paper deals with the unified Wilson plot method used for obtaining heat transfer correlations for finned heat exchangers. In this approach, the direct nonlinear regression is implemented. The numerical example with uncertainty analysis is included as well.
Melting of a Wire Anode Followed by Solidification: A Three-Phase Moving Interface Problem
Authors: Sripada S. S. , Cohen Ira M. , Ayyaswamy P. S.
Published: July 2003

A fine metallic wire electrode is heated from below (by an electric discharge) causing melting and roll-up into a ball by surface tension. After the heating is terminated, a solidification front progresses through the melt until a solid ball is formed and cooled to ambient conditions. In this paper we numerically simulate the heating, melt motion and roll up and subsequent cooling and solidification. This is a three-phase problem (solid, liquid, and the ambient medium—plasma/gas) with two simultaneously moving phase interfaces, the outer one tracked by orthogonal grid generation conformal with the evolving boundary surface at each time interval. A novel observation in this study is that the wire end first drops until the melt radius equals the wire radius and then it begins to roll up into a ball consuming the wire. In other words, the inter-electrode gap first reduces and subsequently increases during an electronic flame off (EFO) discharge heating/phase-change process.
Heat Transfer Between Blockages With Holes in a Rectangular Channel
Authors: Moon S. W. , Lau S. C.
Published: July 2003

Experiments have been conducted to study steady heat transfer between two blockages with holes and pressure drop across the blockages, for turbulent flow in a rectangular channel. Average heat transfer coefficient and local heat transfer distribution on one of the channel walls between two blockages, and overall pressure drop across the blockages were obtained, for nine different staggered arrays of holes in the blockages and Reynolds numbers of 10,000 and 30,000. For the hole configurations studied, the blockages enhanced heat transfer by 4.6 to 8.1 times, but significantly increased the pressure drop. Smaller holes in the blockages caused higher heat transfer enhancement, but larger increase of the pressure drop than larger holes. The heat transfer enhancement was lower in the higher Reynolds number cases. Because of the large pressure drop, the heat transfer per unit pumping power was lower with the blockages than without the blockages. The local heat transfer was lower nearer the upstream blockage, the highest near the downstream blockage, and also relatively high in regions of reattachment of the jets leaving the upstream holes. The local heat transfer distribution was strongly dependent on the configuration of the hole array in the blockages. A third upstream blockage lowered both the heat transfer and the pressure drop, and significantly changed the local heat transfer distribution.
Time Scales for Unsteady Mass Transfer From a Sphere at Low-Finite Reynolds Numbers
Authors: Kleis Stanley J. , Rivera-Solorio Ivan
Published: July 2003

The problem of unsteady mass transfer from a sphere that impulsively moves from rest to a finite velocity in a non-uniform concentration distribution is studied. A range of low Reynolds numbers (Re<1) and moderate Peclet numbers (Pe ranges from 5.6 to 300) is investigated (typical of the parameters encountered in anchorage dependent cell cultures in micro gravity). Using time scales, the effects of flow field development, concentration boundary layer development and free stream concentration variation are investigated. For the range of parameters considered, the development of the flow field has a negligible effect on the time variation of the Sherwood number (Sh). The Sh time dependence is dominated by concentration boundary layer development for early times and free stream concentration variations at later times.
Fluid Dynamic Loading on Curved Riser Pipes
Authors: Miliou Anthi , Sherwin Spencer J. , Graham J. Michael R.
Published: July 2003

In order to gain a preliminary understanding of the fluid dynamics developed past a curved riser pipe, a numerical investigation into the flow past curved cylinders at a Reynolds number of 100 has been performed. To approximate the flow conditions on curved riser pipes, different velocity profiles and flow directions were applied and the corresponding results compared. In addition, the fluid dynamic loading and the wake structures for curved cylinder flows were investigated. The fully three-dimensional simulations were computed with a spectral/hp element method. The computational results were compared with experiments undertaken in the towing tank facility of the Department of Aeronautics of Imperial College.
A Stability Analysis of Risers Subjected to Dynamic Compression Coupled With Twisting
Authors: Ramos, Roberto , Pesce Celso Pupo
Published: July 2003

Risers anchored in a floating system and excited by a moderate sea state are often subjected to dynamic compression near the touchdown point, since the static tension in this region is usually very small. An analytical expression for the critical load of dynamically compressed risers was recently derived by Aranha et al. [1], whose results were compared with numerical simulations, showing a good agreement in several cases. This paper extends Aranha’s results by showing that the well-known Greenhill formula can be used to predict stability conditions in cables/risers having an initial curvature and subjected simultaneously to dynamic compression and twisting. This is done by extending Aranha’s reasoning, of a “local buckling length scale,” a little further, therefore creating a general procedure that enables one to obtain the buckling number n appearing in the classical Greenhill formula. An application to rigid risers is presented and discussed.
Automated Assessment of Ultimate Hull Girder Strength
Authors: Smith M. J. , Pegg N. G.
Published: July 2003

An automated approach to ultimate hull girder strength assessment using DRDC’s ultimate strength analysis suite (ULTSAS) is described. The analysis suite improves the ability to perform rapid ultimate strength assessments by providing access to UK and Canadian analysis codes and databases under a single user interface. The interface also allows for automatic cross-sectional model generation from three-dimensional ship finite element models with the MGDSA program. The main features of the ULTSAS system are described, including cross-sectional modelling, and the use of load-shortening curve databases. The paper also provides a review of the progressive collapse method for determining ultimate strength, which is now used in both the UK and Canadian analysis codes. Two numerical approaches are described, one based on curvature incrementing and the other on moment incrementing. It is shown that the moment incrementing procedure produces more accurate bi-axial interaction curves in some instances. Results are obtained for two damage configurations of the HALIFAX class frigate.
Numerical Study of EHD-Enhanced Forced Convection Using Two-Way Coupling
Authors: Huang M. , Lai F. C.
Published: July 2003

Numerical results are presented for heat transfer enhancement using electric field in forced convection in a horizontal channel. The main objective of the present study is to verify the assumption that is commonly used in the numerical study of this kind of problem, which assumes that the electric field can modify the flow field but not vice versa (i.e., the so-called one-way coupling). To this end, numerical solutions are obtained for a wide range of governing parameters (V0=10, 12.5, 15 and 17.5 kV as well as ui=0.0759 to 1.2144 m/s) using both one-way and two-way couplings. The results obtained, in terms of the flow, temperature, and electric fields as well as the heat transfer enhancement, are thoroughly examined. Since the difference in the results obtained by two approaches is insignificant, it is concluded that the assumption of one-way coupling is valid for the problem considered.
Measurements and Calculations of Spectral Radiation Intensities for Turbulent Non-Premixed and Partially Premixed Flames
Authors: Zheng Yuan , Barlow R. S. , Gore Jay P.
Published: July 2003

Spectral radiation intensities leaving diametric and chord-like paths for six non-sooting flames were measured using an infrared array spectrometer. The spectral radiation intensities were also computed using the mean property approach and a time and space series simulation approach. Turbulence/radiation interactions (TRI) in these flames were investigated by comparing the two sets of computations to the experimental data. The effects of TRI are significant for regions away from the flame axis. The new data and findings are of value in the evaluation of radiation models, which are increasingly used in turbulent combustion calculations.
Evaluation of Combined Heat and Mass Transfer Effect on the Thermoeconomic Optimization of an Air-Conditioning Rotary Regenerator
Authors: Jassim Rahim K.
Published: July 2003

The purpose of this paper is to demonstrate the importance of the use of the exergy analysis in the optimization of the geometry of a periodic-flow regenerator. The optimum geometry of the regenerator is determined using the unit cost of exergy of the warm air delivered as the objective function. The running cost is determined using different unit costs for the pressure component of exergy E˙ΔP and the thermal component of exergy E˙ΔT, which are evaluated separately. The ratio of the two unit costs has been calculated for an air-conditioning application in which the regenerator is used. A mathematical model of condensation, evaporation, thermal conductivity and heat transfer is presented for calculating the fluid and matrix temperatures effect on the regenerator performance. The governing differential equations have been formulated in terms of the characteristic dimensionless groups (Πt,Λt, and Zt).
Collection, Mapping, and Annotation of Over 28,000 cDNA Clones from
japonica
Rice
Authors: Kikuchi Shoshi , Satoh Kouji , Nagata Toshifumi , Kawagashira Nobuyuki , Doi Koji , Kishimoto Naoki , Yazaki Junshi , Ishikawa Masahiro , Yamada Hitomi , Ooka Hisako , Hotta Isamu , Kojima Keiichi , Namiki Takahiro , Ohneda Eisuke , Yahagi Wataru , Suzuki Kohji , Li Chao Jie , Ohtsuki Kenji , Shishiki Toru , Otomo Yasuhiro , Murakami Kazuo , Iida Yoshiharu , Sugano Sumio , Fujimura Tatsuto , Suzuki Yutaka , Tsunoda Yuki , Kurosaki Takashi , Kodama Takeko , Masuda Hiromi , Kobayashi Michie , Xie Quihong , Lu Min , Narikawa Ryuya , Sugiyama Akio , Mizuno Kouichi , Yokomizo Satoko , Niikura Junko , Ikeda Rieko , Ishibiki Junya , Kawamata Midori , Yoshimura Akemi , Miura Junichirou , Kusumegi Takahiro , Oka Mitsuru , Ryu Risa , Ueda Mariko , Matsubara Kenichi , Kawai Jun , Carninci Piero , Adachi Jun , Aizawa Katsunori , Arakawa Takahiro , Fukuda Shiro , Hara Ayako , Hashidume Wataru , Hayatsu Norihito , Imotani Koichi , Ishii Yoshiki , Itoh Masayoshi , Kagawa Ikuko , Kondo Shinji , Konno Hedeaki , Miyazaki Ai , Osato Naoki , Ota Yoshimi , Saito Rintaro , Sasaki Daisuke , Sato Kenjiro , Shibata Kazuhiro , Shinagawa Akira , Shiraki Toshiyuki , Yoshino Masayasu , Hayashizaki Yoshihide
Published: July 2003

We collected and completely sequenced 28,469 full-length complementary DNA clones from
Oryza sativa
L. ssp.
japonica
cv. Nipponbare. Through homology searches of publicly available sequence data, we assigned tentative protein functions to 21,596 clones (75.86%). Mapping of the cDNA clones to genomic DNA revealed that there are 19,000 to 20,500 transcription units in the rice genome. Protein informatics analysis against the InterPro database revealed the existence of proteins presented in rice but not in
Arabidopsis
. Sixty-four percent of our cDNAs are homologous to
Arabidopsis
proteins.
Evolution of Key Cell Signaling and Adhesion Protein Families Predates Animal Origins
Authors: King Nicole , Hittinger Christopher T. , Carroll Sean B.
Published: July 2003

The evolution of animals from a unicellular ancestor involved many innovations. Choanoflagellates, unicellular and colonial protozoa closely related to Metazoa, provide a potential window into early animal evolution. We have found that choanoflagellates express representatives of a surprising number of cell signaling and adhesion protein families that have not previously been isolated from nonmetazoans, including cadherins, C-type lectins, several tyrosine kinases, and tyrosine kinase signaling pathway components. Choanoflagellates have a complex and dynamic tyrosine phosphoprotein profile, and cell proliferation is selectively affected by tyrosine kinase inhibitors. The expression in choanoflagellates of proteins involved in cell interactions in Metazoa demonstrates that these proteins evolved before the origin of animals and were later co-opted for development.
Influence of Life Stress on Depression: Moderation by a Polymorphism in the 5-HTT Gene
Authors: Caspi Avshalom , Sugden Karen , Moffitt Terrie E. , Taylor Alan , Craig Ian W. , Harrington HonaLee , McClay Joseph , Mill Jonathan , Martin Judy , Braithwaite Antony , Poulton Richie
Published: July 2003

In a prospective-longitudinal study of a representative birth cohort, we tested why stressful experiences lead to depression in some people but not in others. A functional polymorphism in the promoter region of the serotonin transporter (5-HT T) gene was found to moderate the influence of stressful life events on depression. Individuals with one or two copies of the short allele of the 5-HT T promoter polymorphism exhibited more depressive symptoms, diagnosable depression, and suicidality in relation to stressful life events than individuals homozygous for the long allele. This epidemiological study thus provides evidence of a gene-by-environment interaction, in which an individual's response to environmental insults is moderated by his or her genetic makeup.
Allosteric Activators of Glucokinase: Potential Role in Diabetes Therapy
Authors: Grimsby Joseph , Sarabu Ramakanth , Corbett Wendy L. , Haynes Nancy-Ellen , Bizzarro Fred T. , Coffey John W. , Guertin Kevin R. , Hilliard Darryl W. , Kester Robert F. , Mahaney Paige E. , Marcus Linda , Qi Lida , Spence Cheryl L. , Tengi John , Magnuson Mark A. , Chu Chang An , Dvorozniak Mark T. , Matschinsky Franz M. , Grippo Joseph F.
Published: July 2003

Glucokinase (GK) plays a key role in whole-body glucose homeostasis by catalyzing the phosphorylation of glucose in cells that express this enzyme, such as pancreatic β cells and hepatocytes. We describe a class of antidiabetic agents that act as nonessential, mixed-type GK activators (GKAs) that increase the glucose affinity and maximum velocity (
V
max
) of GK. GKAs augment both hepatic glucose metabolism and glucose-induced insulin secretion from isolated rodent pancreatic islets, consistent with the expression and function of GK in both cell types. In several rodent models of type 2 diabetes mellitus, GKAs lowered blood glucose levels, improved the results of glucose tolerance tests, and increased hepatic glucose uptake. These findings may lead to the development of new drug therapies for diabetes.
DNA: A Programmable Force Sensor
Authors: Albrecht Christian , Blank Kerstin , Lalic-Mülthaler Mio , Hirler Siegfried , Mai Thao , Gilbert Ilka , Schiffmann Susanne , Bayer Tom , Clausen-Schaumann Hauke , Gaub Hermann E.
Published: July 2003

Direct quantification of biomolecular interaction by single-molecule force spectroscopy has evolved into a powerful tool for materials and life sciences. We introduce an approach in which the unbinding forces required to break intermolecular bonds are measured in a differential format by comparison with a known reference bond (here, a short DNAduplex). In addition to a marked increase in sensitivity and force resolution, which enabled us to resolve single–base pair mismatches, this concept allows for highly specific parallel assays. This option was exploited to overcome cross-reactions of antibodies in a protein biochip application.
Role of MicroRNAs in Plant and Animal Development
Authors: Carrington James C. , Ambros Victor
Published: July 2003

Small RNAs, including microRNAs (miRNAs) and short interfering RNAs (siRNAs), are key components of an evolutionarily conserved system of RNA-based gene regulation in eukaryotes. They are involved in many molecular interactions, including defense against viruses and regulation of gene expression during development. miRNAs interfere with expression of messenger RNAs encoding factors that control developmental timing, stem cell maintenance, and other developmental and physiological processes in plants and animals. miRNAs are negative regulators that function as specificity determinants, or guides, within complexes that inhibit protein synthesis (animals) or promote degradation (plants) of mRNA targets.
Phase Change and the Regulation of Developmental Timing in Plants
Authors: Poethig R. Scott
Published: July 2003

Plants produce different types of organs at different times in shoot development. Along with the major changes in organ morphology that take place during developmental transitions, more gradual patterns of variation occur. The identity of organs produced at a particular position on the shoot is determined by interactions between several independently regulated, temporally coordinated processes. Two of these processes are organ production and the specification of organ identity. Coordination of these processes is accomplished in part by a thermal clock and by signal transduction pathways that mediate the response of plants to light.
Organizing Axes in Time and Space; 25 Years of Colinear Tinkering
Authors: Kmita Marie , Duboule Denis
Published: July 2003

During vertebrate development, clustered genes from the
Hox
family of transcription factors are activated in a precise temporal and spatial sequence that follows their chromosomal order (the “
Hox
clock”). Recent advances in the knowledge of the underlying mechanisms reveal that the embryo uses a variety of strategies to implement this colinear process, depending on both the type and the evolutionary history of axial structures. The search for a universal mechanism has likely hampered our understanding of this enigmatic phenomenon, which may be caused by various and unrelated regulatory processes, as long as the final distribution of proteins (the HOX code) is preserved.
Real-Time Observation of Bimodal Proton Transfer in Acid-Base Pairs in Water
Authors: Rini Matteo , Magnes Ben-Zion , Pines Ehud , Nibbering Erik T. J.
Published: July 2003

The neutralization reaction between an acid and a base in water, triggered after optical excitation, was studied by femtosecond vibrational spectroscopy. Bimodal dynamics were observed. In hydrogen-bonded acid-base complexes, the proton transfer proceeds extremely fast (within 150 femtoseconds). In encounter pairs formed by diffusion of uncomplexed photoacid and base molecules, the reaction upon contact was an order of magnitude slower, in agreement with earlier reported values. These results call for a refinement of the traditional Eigen-Weller picture of acid-base reactions: A three-stage model is introduced to account for all observed dynamics.
Circadian Clocks in Daily and Seasonal Control of Development
Authors: Schultz Thomas F. , Kay Steve A.
Published: July 2003

The rotation of the earth results in regular changes in the light environment, and organisms have evolved a molecular oscillator that allows them to anticipate these changes. This daily molecular oscillator, known as the circadian clock, regulates a diverse array of physiologies across a wide variety of organisms. This review highlights a few of the insights we have into circadian clock regulation of development, in both plants and animals. A common thread linking plants and animals is the use of the circadian clock to sense changes in day length and to mediate a diverse number of photoperiodic responses.
Reason, Rape, and Angst in Behavioral Studies
Authors: Lee P. C.
Published: July 2003

Evolution, Gender, and Rape
. Cheryl Brown Travis, Ed. MIT Press, Cambridge, MA, 2003. 460 pp. $62, £41.50. ISBN 0-262-20143-7. Paper, $24.95, £16.50. ISBN 0-262-70090-5.

The contributors critique Randy Thornhill and Craig Palmer's Natural History of Rape from a variety of perspectives, and they also discuss responses to that book in the media and academia.
Hairpin RNAs and Retrotransposon LTRs Effect RNAi and Chromatin-Based Gene Silencing
Authors: Schramke Vera , Allshire Robin
Published: July 2003

The expression of short hairpin RNAs in several organisms silences gene expression by targeted mRNA degradation. This RNA interference (RNAi) pathway can also affect the genome, as DNA methylation arises at loci homologous to the target RNA in plants. We demonstrate in fission yeast that expression of a synthetic hairpin RNA is sufficient to silence the homologous locus in trans and causes the assembly of a patch of silent Swi6 chromatin with cohesin. This requires components of the RNAi machinery and Clr4 histone methyltransferase for small interfering RNA generation. A similar process represses several meiotic genes through nearby retrotransposon long terminal repeats (LTRs). These analyses directly implicate interspersed LTRs in regulating gene expression during cellular differentiation.
Nota Bene: Romancing the Hole
Authors: Rowan Linda
Published: July 2003

The Black Hole at the Center of Our Galaxy
. Fulvio Melia. Princeton University Press, Princeton, NJ, 2003. 201 pp. $29.95, £19.95. ISBN 0-691-09505-1.

Melia provides a short and lively account of the evidence for the existence of a black hole at the center of the Milky Way Galaxy.
A Semi-Quantitative Analysis of Far-Infrared Absorption in Dynamically Disordered Gallium Arsenide
Authors: Grado-Caffaro M. A. , Grado-Caffaro M.
Published: July 2003

A mathematical expression for the coefficient of optical absorption in amorphous GaAs referred to the far-infrared range is obtained by neglecting the spectrum contribution corresponding to structural disorder. In addition, our results are compared with experimental data and several aspects related to the electronic density of states are discussed.
On the Statistics of an Ideal Gas with Mass Fluctuations and the Boltzman Ergodic Theorem: The Combined Boltzman–Tsallis Statistics
Authors: Botelho Luiz C. L.
Published: July 2003

In this letter, we evaluate the effective velocities probability distribution associated to a classical ideal gas in thermodynamical equilibrium, but in the presence of fluctuations of the (inertial) mass parameter of the molecules. We obtain in the context of linear response theory of the mass fluctuations and the usual Boltzman framework the combined statistics of Boltzman and Tsallis as an outcome of the study for our effective Fractal gas distribution probability. This result explains from first principles the Tsallis-inverse power law distribution previously only speculated on in the literature. Finally, we give a new mathematical proof of the Boltzman ergodic theorem in classical statistics mechanics.