bluuebunny/crossref_metadata_2025 huggingface dataset:
Small-world graphs: characterization and alternative constructions
Authors: Cont Rama , Tanimura Emily
Published: January 2009

Small-world graphs are examples of random graphs which mimic empirically observed features of social networks. We propose an intrinsic definition of small-world graphs, based on a probabilistic formulation of scaling properties of the graph, which does not rely on any particular construction. Our definition is shown to encompass existing models of small-world graphs, proposed by Watts (1999) and studied by Barbour and Reinert (2001), which are based on random perturbations of a regular lattice. We also propose alternative constructions of small-world graphs which are not based on lattices and study their scaling properties.
Multiple-trial conflicts and stochastic evolutionary game dynamics
Authors: Imhof Lorens A.
Published: January 2009

We consider stochastic replicator processes for games that are composed of finitely many trials. Several general results on the relation between Nash equilibria and the long-run behaviour of the stochastic processes are proved. In particular, a sufficient condition is given for almost sure convergence to a state where everyone plays in every trial a strict Nash equilibrium. The results are applied to multiple-trial conflicts based on wars of attrition and on sperm competition games with fair raffles, respectively.
Stochastic Models of Cascading Failures
Authors: Swift Andrew W.
Published: January 2009

What is a ‘cascading failure’? Whilst most people have an intuitive idea of what is meant by cascading, no definition exists within the framework of reliability theory. The aim of this paper is to explore the field of component dependence within a network structure, and to construct a definition of cascading failure.
Run Statistics Defined on the Multicolor URN Model
Authors: Eryilmaz Serkan
Published: January 2009

Recently, Makri, Philippou and Psillakis (2007b) studied the exact distribution of success run statistics defined on an urn model. They derived the exact distributions of various success run statistics for a sequence of binary trials generated by the Pólya-Eggenberger sampling scheme. In our study we derive the joint distributions of run statistics defined on the multicolor urn model using a simple unified combinatorial approach and extend some of the results of Makri, Philippou and Psillakis (2007b). As a consequence of our results, we obtain the joint distributions of success and failure runs defined on the two-color urn model. The results enable us to compute the characteristics of particular consecutive-type systems and start-up demonstration tests.
On Nonoptimality of Bold Play for Subfair Red-And-Black with a Rational-Valued House Limit
Authors: Chen May-Ru , Chung Pei-Shou , Hsiau Shoou-Ren , Yao Yi-Ching
Published: January 2009

In the subfair red-and-black gambling problem, a gambler can stake any amount in his possession, winning an amount equal to the stake with probability w and losing the stake with probability 1 − w, where 0 < w < ½. The gambler seeks to maximize the probability of reaching a fixed fortune (to be normalized to unity) by gambling repeatedly with suitably chosen stakes. In their classic work, Dubins and Savage (1965), (1976) showed that it is optimal to play boldly. When there is a house limit of l (0 < l < ½), so that the gambler can stake no more than l, Wilkins (1972) showed that bold play remains optimal provided that 1 / l is an integer. On the other hand, building on an earlier surprising result of Heath, Pruitt and Sudderth (1972), Schweinsberg (2005) recently showed that, for all irrational 0 < l < ½ and all 0 < w < ½, bold play is not optimal for some initial fortune. The purpose of the present paper is to present several results supporting the conjecture that, for all rational l with 1 / l not an integer and all 0 < w < ½, bold play is not optimal for some initial fortune. While most of these results are based on Schweinsberg's method, in a special case where his method is shown to be inapplicable, we argue that the conjecture can be verified with the help of symbolic-computation software.
Continuous-State Branching Processes and Self-Similarity
Authors: Kyprianou A. E. , Pardo J. C.
Published: January 2009

In this paper we study the α-stable continuous-state branching processes (for α ∈ (1, 2]) and the α-stable continuous-state branching processes conditioned never to become extinct in the light of positive self-similarity. Understanding the interaction of the Lamperti transformation for continuous-state branching processes and the Lamperti transformation for positive, self-similar Markov processes gives access to a number of explicit results concerning the paths of α-stable continuous-state branching processes and α-stable continuous-state branching processes conditioned never to become extinct.
Fishing for the genetic basis of cardiovascular disease
Authors: Dahme Tillman , Katus Hugo A. , Rottbauer Wolfgang
Published: January 2009

Cardiovascular disease (CVD) has recently overtaken infectious disease to become the biggest global killer. Genetic factors have emerged as being of major importance in the pathogenesis of CVD. Owing to disease heterogeneity, variable penetrance and high mortality, human genetic studies alone are not sufficient to elucidate the genetic basis of CVD. Animal models are needed to identify novel genes that are involved in cardiovascular pathology and to verify the effect of suspected disease genes on cardiovascular function. An intriguing model organism is the zebrafish danio rerio. Several features of the zebrafish, such as a closed cardiovascular system, transparency at embryonal stages, rapid and external development, and easily tractable genetics make it ideal for cardiovascular research. Moreover, zebrafish are suitable for forward genetics approaches, which allow the unbiased identification of novel and unanticipated cardiovascular genes. Zebrafish mutants with various cardiovascular phenotypes that closely correlate with human disease, such as congenital heart disease, cardiomyopathies and arrhythmias, have been isolated. The pool of zebrafish mutants, for which the causal gene mutation has been identified, is constantly growing. The human orthologues of several of these zebrafish genes have been shown to be involved in the pathogenesis of human CVD. Cardiovascular zebrafish models also provide the opportunity to develop and test novel therapeutic strategies, using innovative technologies such as high throughput in vivo small molecule screens.
Dynamic complexes of A-type lamins and emerin influence adipogenic capacity of the cell via nucleocytoplasmic distribution of β-catenin
Authors: Tilgner Katarzyna , Wojciechowicz Kamila , Jahoda Colin , Hutchison Christopher , Markiewicz Ewa
Published: January 2009

It is well documented that adipogenic differentiation of the cell is associated with downregulation of Wnt/β-catenin signalling. Using preadipocytes and dermal fibroblasts, we have found that activation of the adipogenic program was associated with marked changes in the expression of nuclear β-catenin-interacting partners, emerin and lamins A/C, to influence expression and activation of peroxisome proliferators-activated receptors γ (PPARγ). In addition, silencing of protein expression with siRNA revealed that β-catenin and emerin influenced each other's levels of expression and the onset of adipogenesis, suggesting that changes in the expression of nuclear lamina proteins were intimately linked to the stability of β-catenin. By contrast, dermal fibroblasts, which are emerin null, demonstrated increased nuclear accumulation of stable β-catenin and constant lamin expression. This was also associated with an unusual adipogenic capacity of the cells, with adipogenesis occurring in the presence of activated β-catenin but declining upon silencing of the protein expression with siRNA. We propose that the process of adipogenesis is affected by a dynamic link between complexes of emerin and lamins A/C at the nuclear envelope and nucleocytoplasmic distribution of β-catenin, to influence cellular plasticity and differentiation.
FAK engages multiple pathways to maintain survival of fibroblasts and epithelia – differential roles for paxillin and p130Cas
Authors: Zouq Nadia K. , Keeble James A. , Lindsay Jennefer , Valentijn Anthony J. , Zhang Lu , Mills Deborah , Turner Christopher E. , Streuli Charles H. , Gilmore Andrew P.
Published: January 2009

Different cell types interpret their distinct extracellular matrix (ECM) environments to bring about specific cell fate decisions, and can differentiate or undergo apoptosis depending on their local adhesive interactions. Apoptosis in response to an inappropriate ECM environment is termed `anoikis', or homelessness. Several studies, utilising a variety of cell types, have indicated a common, crucial role for focal adhesion kinase (FAK) in suppressing anoikis. A wide range of different integrins can activate FAK, raising the question of how cell type specific effects are regulated. In this study, we have used a constitutively active form of FAK to examine the mechanism of FAK-mediated survival signalling in cell types from distinct embryonic lineages that show differing sensitivities to anoikis. We demonstrate that both fibroblasts and epithelial cells prevent anoikis through FAK activation. We show that FAK activates multiple downstream pathways in order to suppress anoikis. However FAK regulates survival through a more restricted set of pathways in the more anoikis-sensitive epithelial cells. Furthermore, we identify a novel role for paxillin in apoptosis suppression.
Regulation of Rap1 activity is required for differential adhesion, cell-type patterning and morphogenesis inDictyostelium
Authors: Parkinson Katie , Bolourani Parvin , Traynor David , Aldren Nicola L. , Kay Robert R. , Weeks Gerald , Thompson Christopher R. L.
Published: January 2009

Regulated cell adhesion and motility have important roles during growth, development and tissue homeostasis. Consequently, great efforts have been made to identify genes that control these processes. One candidate is Rap1, as it has been implicated in the regulation of adhesion and motility in cell culture. To further study the role of Rap1 during multicellular development, we generated a mutant in a potential Rap1 GTPase activating protein (RapGAPB) in Dictyostelium. rapGAPB– cells have increased levels of active Rap1 compared with wild-type cells, indicating that RapGAPB regulates Rap1 activity. Furthermore, rapGAPB– cells exhibit hallmark phenotypes of other known mutants with hyperactivated Rap1, including increased substrate adhesion and abnormal F-actin distribution. However, unlike these other mutants, rapGAPB– cells do not exhibit impaired motility or chemotaxis, indicating that RapGAPB might only regulate specific roles of Rap1. Importantly, we also found that RapGAPB regulates Rap1 activity during multicellular development and is required for normal morphogenesis. First, streams of aggregating rapGAPB– cells break up as a result of decreased cell-cell adhesion. Second, rapGAPB– cells exhibit cell-autonomous defects in prestalk cell patterning. Using cell-type-specific markers, we demonstrate that RapGAPB is required for the correct sorting behaviour of different cell types. Finally, we show that inactivation of RapGAPB affects prestalk and prespore cell adhesion. We therefore propose that a possible mechanism for RapGAPB-regulated cell sorting is through differential adhesion.
Fast mass-fraction-burned calculation using the net pressure method for real-time applications
Authors: Mittal M , Zhu G , Schock H
Published: January 2009

The mass fraction burned (MFB) is determined from the analysis of measured in-cylinder pressure data. In this paper, a net pressure method (model 2) is used to evaluate the MFB curves at different load conditions (3.3 bar indicated mean effective pressure and wide-open throttle) using a constant polytropic index. Results are compared with the well-known Rassweiler—Withrow method (model 1), which is a linear model for the polytropic index. Model 2 showed good agreement with model 1 at high-load conditions; however, it predicts slower combustion at part-load conditions than that of model 1. It is found that the proper selection of the polytropic index n and the determination of the end of combustion are the important parameters for calculating the MFB curves using model 2. The modified form of model 2 compares well with the results of model 1 for evaluating the MFB at part-load conditions. The MFB results of the modified form (of model 2) also show good agreement with model 1 at high-load conditions. Model 2 has an advantage that the data-processing time is short enough to allow for online processing.
An engine-control-unit-in-the-loop simulator of a common-rail diesel engine for cylinder-pressure-based control
Authors: Yoon M , Chung N-H , Lee M-K , Sunwoo M-H
Published: January 2009

A non-linear dynamic model of the common-rail direct-injection (CRDI) diesel engine was proposed and verified through engine tests. Typical engine models used in control applications do not compute the pressure within the cylinder. This is, however, not ideal for cases when the model needs to be run over a wide range of operating conditions, or if the controller uses the cylinder pressure itself as a measured variable. The developed engine model includes in-cylinder pressure dynamics as the heart of the cylinder-by-cylinder engine model (CCEM). The inclusion of cylinder pressure dynamics makes it possible to reflect precisely the influence of the changes in inputs, and thus the applicable operating range of the engine model is expanded. Moreover, a cylinder-pressure-based control algorithm can be developed and easily evaluated on this model. Based on the CCEM, a distributed electronic-control-unit-in-the-loop simulation platform was developed for the CRDI diesel engine.
Numerical investigation of soot reduction potentials with diesel homogeneous charge compression ignition combustion by an improved phenomenological soot model
Authors: Jia M , Peng Z-J , Xie M-Z
Published: January 2009

An improved phenomenological soot model coupled with a reduced n-heptane chemical mechanism was implemented into KIVA-3V code to describe soot formation and oxidation processes in diesel homogeneous charge compression ignition (HCCI) combustion. This model was first validated by the shock tube experiments with a rich n-heptane mixture over wide temperature and pressure ranges. The computational results demonstrate that the phenomenological soot model is capable of predicting the soot yield, particle diameter, and number density with satisfactory accuracy. Then the model was applied to investigate the influence of the orifice diameter and injection pressure on soot emissions in a constant-volume combustion vessel under typical diesel combustion conditions. The predictions showed qualitative agreement with the measurements on the soot volume fraction distribution. The results also indicate that the soot formation can almost be suppressed as the local equivalence ratio is kept lower than 2.0. Finally, the model was used to explore the potentials of soot reduction with HCCI combustion for diesel engines. The overall trend of soot with the variations in the start of injection timing was well reproduced by the model. With the help of an equivalence ratio—temperature map, it was found that nitrogen oxide emissions could be markedly reduced by applying a high exhaust gas recirculation rate and relative low compression ratio for diesel HCCI engines. However, the mixture preparation by using a multi-hole injector with early injection strategy remains a limitation for further reduction in soot emissions.
Analysis and optimization of a butterfly valve disc
Authors: Song X G , Wang L , Park Y C
Published: January 2009

A butterfly valve is a type of flow control device, which is widely used to regulate a fluid flowing through a section of pipe. Currently, analyses and optimization are of special important in the design and usage of butterfly valves. For the analysis, finite element method (FEM) is often used to predict the safety of valve disc, and computational fluid dynamics (CFD) is commonly used to study the flow characteristics of valve. However, it is difficult to obtain accurate results for the optimization of butterfly valve due to the high non-linearities. For this reason, metamodels or surrogate model methods are extensively employed. This paper integrates metamodel with FEM and CFD analysis to optimize a traditional butterfly valve, where the weight of the valve disc is the design objective, and the strength safety of disc and the pressure loss coefficient of valve are constraints. Kriging model is employed as a surrogate model to formulate the objectives and constrains, and the orthogonal array is used as design of experiment to sample the computer analysis. The optimum results with the corresponding variable combinations for the valve disc are obtained easily by this method. Moreover, the structural and fluid analyses with the obtained optimum variable combinations are conducted again to verify the accuracy of the optimization method. The results demonstrate the capability and potential of this method, which integrates the Kriging model with FEM and CFD analysis, in solving the optimization of a butterfly valve.
Numerical simulation of embankment—structure transition design
Authors: Gallego Giner I , López Pita A
Published: January 2009

The experience of several European railway systems has shown that problems occur frequently in zones with embankment—structure transitions, and these areas therefore require repeated maintenance. To date, no adequate solution for these zones has been demonstrated, and different European railway systems have adopted different design approaches.

In this work, a finite-element model is developed to simulate the behaviour of embankment—structure transitions to improve the methods available for modelling railway track designs. The most distinctive characteristic of the model proposed here is its attempt to simulate the real behaviour of the diverse materials that make up the structure of the track in a transition. To achieve this, a three-dimensional model with boundary conditions that more closely resemble real conditions was used; the model assumes that the surface defining the embankment slope is free and it takes into account the elastoplastic behaviour of the soil.

This model was tested by numerical calculations of several case studies created from different values of geotechnical and geometrical parameters of transition zones. The results from this analysis will help to define new criteria for improving the design of embankment—structure transitions.
A numerical model for the analysis of unsteady train braking and releasing manoeuvres
Authors: Cantone L , Crescentini E , Verzicco R , Vullo V
Published: January 2009

In this article, a numerical model for the pneumatic braking system of traditional freight trains is developed and tested. The validation of the results is performed through the comparison of the numerical results with analogous experimental data. The model has proved to be reliable and computationally efficient either for simple braking and releasing manoeuvres or for complex/transient manoeuvres. This model has been included in the software TrainDy, and thanks to its key features it has gained the Union Internationale Chemin de fer certification.
Vertical axis wind turbine induced velocity vector theory
Authors: Farthing S P
Published: January 2009

Double multiple stream tube (DMST) models of the vertical axis wind turbine (Vawt) take its interference as unidirectional flow against the wind. However, in the standard blade-element momentum (BEM) theory of the horizontal axis wind turbine (Hawt), the interference velocity is proportional to the lift vector normal to the apparent wind. A high design tip speed ratio brings the apparent wind to tangential, making the BEM interference flow radial across the Vawt blades. The lateral drift induced by the Vawt-bound vorticity and the mean reaction velocity to the torque are not upwind at all. A new vector BEM formulation includes such crosswind Vawt interference. For the two Vawt passes through the wind, it predicts a lower and narrower operating peak of tangent and ‘passive pitch’ Vawts than the DMST or Hawts. However, it gives the pitch cam shape for broadening the operating peak and for benignly avoiding high downwind drag and reverse wake flow. The Prandtl tip correction is included and compared to isolated wing aspect ratio factors.
A thermohydrodynamic analysis of a lubrication film between rough seal faces
Authors: Luan Z , Khonsari M M
Published: January 2009

A thermohydrodynamic model is presented to analyse the lubrication film between seal faces with provision for surface roughness. A simplified energy equation is derived and solved analytically. The variation of temperature in both radial and axial directions is considered. The effect of various parameters on the thermal behaviour of sealing gap is explored. It is shown that the temperature variation across the sealing gap can be significant, raising questions about the validity of constant viscosity solution often made in analyses.
Determination of the sampling interval in surface roughness measurements with implications to engineering tribo-surface characterization and evaluation
Authors: Chang L
Published: January 2009

This article presents the theoretical basis from which a sampling interval may be meaningfully determined in the surface roughness measurements for engineering tribology applications. Equations are derived that relate the measurement sampling interval to the material properties of the part and the RMS roughness of the surface. The feasibility of the roughness measurements is discussed. The study also reveals some insights into the surface characterization parameters and the quality of surface run-in processes.
Load capacity of aerodynamic foil thrust bearings supported by viscoelastic material
Authors: Somaya K , Yoshimoto S , Miyatake M
Published: January 2009

In recent years aerodynamic bump foil bearings have attracted considerable attention for the field of oil-free turbomachines. However, the shape of the bump foils is usually very complicated and the manufacturing of these bump foils is very troublesome. Moreover, in foil bearings applied to turbomachines, such as compressors and blowers, it is not necessary to use flexible supports made of metals because the operating temperature does not rise much. Therefore, in this article, two types of taper-land foil thrust bearings supported by viscoelastic material are proposed for easier manufacturing of foil bearings. In this work the load capacity of the proposed foil bearings experimentally and numerically was investigated. It was confirmed that the proposed bearings could be easily manufactured and operate well as aerodynamic thrust bearings. In addition, it was found that inserting a metal plate between the top foil and the viscoelastic support at the land region could improve the load capacity, and that the load capacity of the proposed foil bearing reached 160 N at 20 000 r/min.
Real-time simulation of a COGAG naval ship propulsion system
Authors: Altosole M , Benvenuto G , Figari M , Campora U
Published: January 2009

Design and optimization of the propulsion system is a crucial task of the ship design process. The behaviour of the propulsion system, in transient conditions as well as in steady state, is greatly affected by the capability of the control system to manage the available power and to achieve the desired performance in the shortest time.

The selection of a proper control scheme is a trade-off between different and conflicting needs. Two of the opposites are: increasing the ship operability by adding more functions and more controls; and reducing the control system development and installation time and cost.

In this paper, the rapid prototyping and testing procedure for the development of the propulsion controller of the new Italian aircraft carrier Cavour is presented, using real-time hardware-in-the-loop (RT-HIL) simulation. The procedure is based on a wide use of simulation technology. First, a complete dynamical model of the ship propulsion plant was developed. Then, batch simulation was used to develop the best possible control scheme. Finally, RT-HIL simulation was used to debug the real controller software and to tune the controller parameters before sea trials.

The application of the procedure led to a significant reduction in the development phase of the controller design. Furthermore, the adoption of the RT-HIL technology greatly reduced the time spent to tune the control system during the ship delivery phase.
Drag and inertia coefficients for horizontally submerged rectangular cylinders in waves and currents
Authors: Venugopal V , Varyani K S , Westlake P C
Published: January 2009

The results of an experimental investigation carried out to measure combined wave and current loads on horizontally submerged square and rectangular cylinders are reported in this paper. The wave and current induced forces on a section of the cylinders with breadth—depth (aspect) ratios equal to 1, 0.5, and 0.75 are measured in a wave tank. The maximum value of Keulegan—Carpenter ( KC) number obtained in waves alone is about 5 and Reynolds ( Re) number ranged from 6.397 ×103 to 1.18 ×105. The drag ( CD) and inertia ( CM) coefficients for each cylinder are evaluated using measured sectional wave forces and particle kinematics calculated from linear wave theory. The values of CD and CM obtained for waves alone have already been reported (Venugopal, V., Varyani, K. S., and Barltrop, N. D. P. Wave force coefficients for horizontally submerged rectangular cylinders. Ocean Engineering, 2006, 33, 11—12, 1669—1704) and the coefficients derived in combined waves and currents are presented here. The results indicate that both drag and inertia coefficients are strongly affected by the presence of the current and show different trends for different cylinders. The values of the vertical component inertia coefficients ( CM Y) in waves and currents are generally smaller than the inertia coefficients obtained in waves alone, irrespective of the current's magnitude and direction. The results also illustrate the effect of a cylinder's aspect ratio on force coefficients. This study will be useful in the design of offshore structures whose columns and caissons are rectangular sections.
Weight-Based Argatroban Dosing Nomogram for Treatment of Heparin-Induced Thrombocytopenia
Authors: Ansara Alexander J , Arif Sally , Warhurst Robert D
Published: January 2009

BACKGROUND

Manufacturer recommendations for argatroban use in the setting of heparin-induced thrombocytopenia (HIT) state that the dosage should be titrated to a goal activated partial thromboplastin time (aPTT) of 1.5–3 times the baseline aPTT. The lack of a clear dosing strategy with argatroban may result in delayed stabilization of aPTT. There are no published nomograms to guide the dosing of argatroban.

OBJECTIVE

To study the anticoagulant effect and incidence of bleeding and thrombotic events in patients receiving argatroban, with doses determined using a weight-based nomogram.

METHODS

Patients with suspected or documented HIT at an 800-bed teaching community hospital were prospectively treated, in a nonrandomized, nonblinded manner, with argatroban; dosage adjustments were made according to 1 of 2 variations of a dosing nomogram: standard or hepatic/critically ill. The primary outcomes were time to aPTT stabilization and percentage of patients whose aPTTs were within the therapeutic range of 45–90 seconds at 6, 12, 24, 48, 72, and 96 hours. Secondary outcomes were the percentage of patients whose aPTTs were subtherapeutic, supratherapeutic, or above the therapeutic threshold of 45 seconds at each time interval; incidence of thrombotic events; number of dosage adjustments to achieve stabilization; and number of major bleeding events.

RESULTS

Fifty-one patients were prospectively treated using the standard (n = 34) and hepatic/critically ill (n = 17) nomograms. Mean time to aPTT stabilization was 16.25 hours with the standard nomogram and 27.05 hours with the hepatic/critically ill nomogram. The percentages of patients with aPTTs within the therapeutic range at each time interval were 82.4%, 82.4%, 88.2%, 96.4%, 100%, and 100% with the standard nomogram and 58.8%, 82.4%, 76.5%, 93.3%, 100%, and 90.9% with the hepatic/critically ill nomogram. There were no thrombotic events after the initiation of argatroban. Three cases of major bleeding occurred.

CONCLUSIONS

The nomogram is an effective dosing tool for achieving and maintaining therapeutic levels of anticoagulation.
Increases in C-Reactive Protein May Predict Recurrence of Clozapine-Induced Fever
Authors: Kohen Izchak , Afzal Noman , Hussain Saira , Manu Peter
Published: January 2009

OBJECTIVE

To report a case of recurrent clozapine-induced fever that was associated with a rise in C-reactive protein (CRP).

CASE SUMMARY

A 73-year-old man with Lewy Body dementia was admitted for psychosis. He was treated with clozapine (initial dose 12.5 mg/day, titrated to 75 mg/day over 15 days). On day 15 of clozapine therapy, he developed a benign fever (maximum 38.4 °C) that was associated with a rise in the CRP level (3.96 mg/dL). The level normalized when clozapine was discontinued. However, when the patient was rechallenged with clozapine, the CRP level became elevated (4.36 mg/dL) after 3 days of therapy, with a subsequent recurrence of fever (38.7 °C).

DISCUSSION

We postulate that the elevation in CRP levels and the subsequent fever were caused by the effects of clozapine on the cytokine system via interleukin-6 and tumor necrosis factor-α, resulting in an inflammatory response with an acute phase reaction. This case is unique, as it is the first reported in the literature associating a recurrence of clozapine-induced fever with the known immunomodulatory effects of clozapine on cytokines and CRP level. According to the Naranjo probability scale, this adverse effect is probably associated with clozapine.

CONCLUSIONS

Clozapine-related fever is generally benign but difficult to assess and manage, as it can be confused with much more serious conditions. Further research is needed to study whether CRP is a useful tool in predicting and managing clozapine fever.
Response to Lindsay, Mansour, Beaudry, Leach and Bertrand's Sequential lineup presentation: Patterns and policy
Authors: Malpass Roy S. , Tredoux Colin G. , McQuiston‐Surrett Dawn
Published: January 2009

This paper is a response to the earlier paper by Lindsay, Mansour, Beaudry, Leach and Bertrand (2009). We argue that eyewitness research is an important public good and that high‐quality in research and policy formulations offered to the public interest is required to maintain our standing of trust. We argue that even though sequential lineups have been successfully codified in some jurisdictions as the exclusive eyewitness identification procedure, the claim of sequential superiority is built upon errors in the research process and that the evidence of reduced false identification with sequential lineups is completely offset by reductions in correct identifications. We reject the idea that the loss of correct identifications can be dismissed as guessing on the basis that this is speculative and that there is no published empirical support for the idea. We reject the idea that false identifications are necessarily more valuable for society to reduce than are correct identifications to achieve. Improvements in eyewitness identification are important, and interesting lines of investigation are available. It is questionable whether the sequential lineup is important among them.
A Relative Analysis of Downhill and Cross-Country Ski Injuries
Authors: Shealy Jasper E. , Miller David A.
Published: January 2009

This is a clinical analysis of XC and DH injuries reported thru the CPSC NEISS data files. It suggests that there are significant differences between the two sports and that there are occasionally significant interactions with gender as well. There are some implications with regard to injury mechanisms as well as hardware factors. In order to more fully understand and interpret these findings, it will be necessary to couple these findings with an examination of the populations at risk in a quasi-epidemiological methodology.
Warning Compliance: Behavioral Effects of Cost and Consensus
Authors: Wogalter Michael S. , McKenna Nancy A. , Allison Scott T.
Published: January 2009

Two laboratory experiments were conducted to examine the behavioral effects of cost and consensus on warning compliance. Subjects performed a chemistry demonstration task using a set of instructions that contained a warning directing them to wear a safety mask and gloves. In Experiment 1, cost was manipulated by locating the masks and gloves in either an accessible location (low cost) or a less accessible location (high cost). In Experiment 2, consensus was manipulated by the additional presence of a confederate subject who either did or did not comply with the warning. The results showed reduced compliance to the warning when the cost was high, and that the compliance rate was biased up or down depending on the behavior of the confederate. Implications of this research for facilitating warning effectiveness and safety are discussed.
Safety Perceptions and Information Sources for ATVs
Authors: Karnes Edward W. , Leonard S. David , Newbold Herbert C.
Published: January 2009

Safety issues concerning all-terrain vehicles (ATVs) have become important for human factors professionals, becasuse of the need to reduce the accidents and injuries associated with their use. Human factors experts have also been called upon to testify in legal suits occasioned by some accidents. This paper discusses some of the problems associated with the safety of ATVs and presents data concerning riders and observers ability to estimate their speed. Speed estimates are lower than actual speeds at low speeds and higher than actual speeds at high speeds. It is concluded that information about the speed capabilities of ATVs is important consumer information and should be made conspicuous in advertising and other informational channels about ATVs.
Time Estimation Performance Before, during and after Physical Activity
Authors: Mihaly T. , Hancock P.A. , Vercruyssen M. , Rahimi M.
Published: January 2009

An experiment is reported which evaluated performance on a 10-sec time interval estimation task before, during and after physical work on cycle ergometer at intensities of 30 and 60% VO2max, as scaled to the individual subject. Results from the eleven subjects tested indicate a significant increase in variability of estimates during exercise compared to non-exercise phases. Such a trend was also seen in the mean of estimates, where subjects significantly underestimated the target interval (10 seconds) during exercise. Subjects also performed more accurately with information feedback than without knowledge of results, but they were still not able to overcome the effects of exercise. As suggested by the experimental findings, decreased estimation accuracy and increased variability can be expected during physical work and is part of a body of evidence which indicates that exercise and its severity has a substantive impact on perceptual and cognitive performance.
Risktaking and Driver Behaviors: A Laboratory Study
Authors: Shoptaugh Carol F.
Published: January 2009

A number of variables have been implicated as predictors of actual risky driving behaviors. However, due to differing methodologies, the literature shows few consistent findings. The current study is an attempt to establish a more complete understanding of the relationship between risk related characteristics and actual risktaking decisions. It was predicted that individuals who had a greater propensity for taking risks would also be more prone to making risky decisions in a simulated driving task.

Sixty subjects (30 male, 30 female) were selected based on their Kogan and Wallach Choice Dilemma risktaking scores (15 high and 15 low risktakers in each gender group). Subjects participated in two 1 1/2 hour experimental sessions. Session one was a video tape risk choice session and session two, a battery of demographic, driving and risktaking characteristic questionnaires were given.

The most significant finding in this study involved the misuse of speed and distance in making turn decisions. All subjects adopted a safer criterion than the normative model for left turn gap distances, but for right turn merging gaps high risktaking subjects perceived significantly more gaps as safe than did low risktaking subjects. Further, as speed increased from 30mph to 55mph all subjects believed more gaps to be safe for right turn merging. This miscalculation could result in a rear end accident.

Most demographic, driver and risktaking measures failed to correlated significantly with risky decision making. Only the Choice Dilemma and the Pelz-Schuman Impulsivity questionnaire correlated with each other and the risky driver decisions.
How Physical Work Activity and Certain Earmuff Design Attributes Influence Achieved Hearing Protection
Authors: Casali John G. , Grenell James F.
Published: January 2009

Laboratory tests of personal hearing protectors typically overestimate the attenuation performance of the devices in the workplace, where a number of factors reduce protection levels. This research investigated several practical factors including the influence of the user's work-related movement, and variations in headband compression force and earcup cushion material (liquid- or foam-filled) on the noise attenuation achieved with earmuff hearing protectors. Attenuation data were collected on 24 subjects both prior-to and following completion of a simulated work task. Work-related movement was found to significantly decrease attenuation. A high compression headband provided increased attenuation, while there was no significant difference between cushion types as to protection achieved.
Effectiveness of Product Safety Warnings over Time, and the Generalization of Warning Signs
Authors: Orr Madeleine , Hughes Stanley T.
Published: January 2009

The extent to which consumer's attention for safety signs varies over time and the extent to which consumer's impression of product safety are altered by the presence of a safety sign were investigated. A total of 60 subjects had one of two types of signs (safety message or security message) placed on the front of a VDU. Subjects were administered a questionnaire after either one or three weeks of exposure to the signs. Results indicate that safety signs can be rapidly habituated to if the sign's content is not seen as relevant to the task at hand. In addition it was found that the presence of a safety sign resulted in subjects identifying more product related safety hazards.
The Effects of Rumble Strips on Performance of Sober and Alcohol-Dosed Subject Drivers
Authors: Gawron Valerie J. , Ranney Thomas A.
Published: January 2009

Accident studies have identified nighttime conditions on rural roads as particular problems for alcohol-impaired drivers. Uneventful driving is hypothesized to result in progressive degradation of tracking performance and a reduced ability to handle the demands of hazardous locations, such as curves. To address these problems, a simulated rumble strip was evaluated experimentally. Six subjects drove an instrumented vehicle over a closed course under two conditions (presence versus absence of rumble strips) and three levels of BAC (0.00, 0.07, 0.12%). The effects of the rumble strips were evaluated from both road-departure characteristics (lane departure and accident frequency, maximum distance off the road, mean time off the road per departure, time between successive departures) and overall driving performance (means and standard deviations of velocity and lateral position). Rumble-strip presence was associated with increased time between successive left-side departures, increased mean velocity, and reduced speed variability. There were no significant differences between rumble-strip presence and absence for right-side departures.
Experimental Studies of Daytime Running Light Design Factors
Authors: Baker Clifford C. , Kirkpatrick Mark , Heasly Christopher C.
Published: January 2009

Data from accident rate field tests have suggested that the use of Daytime Running Lights (DRL) on vehicles may have potential for reduction of collision likelihood and severity. With regard to the possible introduction of DRL in the United States, a number of research and design issues have arisen. These involve effects of design parameters on vehicle conspicuity under daylight conditions including central lamp intensity, beam distribution, lamp area, lamp color, number of lamps, and lamp/background contrast. Experiments were conducted to determine effects of DRL design parameters on peripheral detection of an oncoming vehicle under daylight conditions, detection of operating turn signals in the presence of a masking DRL, and degree of discomfort glare produced by DRL under twilight conditions.
A Robot Safety Experiment Varying Robot Speed and Contrast with Human Decision Cost
Authors: Etherton John , Sneckenberger John E.
Published: January 2009

An industrial robot safety experiment was performed to find out how quickly subjects could respond to unexpected robot motion at selected slow robot speeds and how frequently they did not respond when a signal (an unexpected motion) should have been detected. The dependent variable in the experiment was the overrun distance beyond an expected stopping point that a robot arm traveled before a person actuated a pushbutton to stop the robot. A robotics technician risks being fatally crushed if a robot should trap the person against a fixed object. This risk can be reduced if, during programming and troubleshooting tasks, the robot is moving at a slow speed which gives the worker sufficient time to actuate an emergency stop device before the robot can reach the person. A General Electric P-50 robot was programmed to provide the experimental situation. Nine subjects were tested, all in the age range 20–30. The subjects were male volunteers, not currently working in a job involving robot programming or maintenance.
Model for Measuring Complex Performance in an Aviation Environment
Authors: Hahn Heidi Ann
Published: January 2009

An experiment was conducted to identify models of pilot performance through the attainment and analysis of concurrent verbal protocols. Sixteen models were identified. Novice and expert pilots differed with respect to the models they used. Models were correlated to performance, particularly in the case of expert subjects. Models were not correlated to performance shaping factors (i.e., workload).
Using Robust Statistics and Distribution Parameters to Establish Valid Individual Differences in Computer-Based Cognitive Testing
Authors: Fairbank Benjamin A.
Published: January 2009

Data gathered in large-scale computer-based cognitive laboratories occasionally appear less orderly than data gathered on similar tasks in laboratories where close interaction between subject and experimenter is possible. The present research addressed the question of whether the use of robust statistics could make such data appear more orderly and lawful. Of related interest was the question of whether parameters which describe whole distributions of data, rather than only means and standard deviations, could be used to establish reliable and valid individual differences. For the large sample sizes used here the robust estimators did not outperform standard statistics. The distribution parameters were not sufficiently reliable to be useful in characterizing psychological processes.
The Effect of Goals and Type A-B Behavior on Changes in Bias and Sensitivity
Authors: Lewis Robert E.
Published: January 2009

The effects of a situational and an individual differences variable on changes in bias and sensitivity during a proofreading task are examined. Externally set goals provided situational parameters while the Type A-B behavior pattern provided a measure of individual differences. Subjects responded to goals of increasing difficulty by increasing their performance as measured by the amount of text proofread and by decreasing their sensitivity. Thus, subjects attempted to meet a situational demand to produce more by increasing the quantity of their output at the expense of quality.
Evaluation of an Automated Series of Single and Multiple-Psychomotor and Dichotic Listening Tasks
Authors: Griffin Glenn R.
Published: January 2009

A series of automated psychomotor and dichotic listening tasks, which require little administrative support and provide automatic scoring of performance, has been developed. The automated tasks account for additional variance in predicting Navy flight training performance beyond that of current selection tests.
Critical Linkages: Top Management's Role in Making Technology Work
Authors: Dray Susan M.
Published: January 2009

It is clear that it is critical to have technical systems which are “linked to the business strategy”, but exactly how to do this remains largely undocumented. This paper presents a case study of how the Senior Management Technology Steering Committee at IDS Financial Services has begun to forge this link.
The Matrix Organization: Can the Human Factors Specialist Thrive or Merely Survive?
Authors: Bowen Charles
Published: January 2009

An increasing amount of Human Factors (HF) Specialists are providing their services through matrix organizations. If the Human Factors Specialist is to be successful, an understanding of recent organizational research involving matrix organizations is important. This paper differentiates among three basic types of organizations: the Functional organization, the Product organization, and the Matrix organization and examines the organizational pressures that force organizations to turn to a matrix organization. The advantages and disadvantages are explored. As the matrix structure grows in popularity, Human Factors Specialists familiar with the principles of a matrix organization, will be better equipped to deliver their services in the most effective manner.
A New Keyboard with Chorded Ternary Keys
Authors: Kroemer Karl H. E. , Fathallah Fadl A. , Langley Lawrence W.
Published: January 2009

A new keyboard has been used in preliminary tests. Each key has 3 state conditions (“ternary key”) and is moved by horizontal displacement of the fingertip, usually together with another key (in “chords”). Little is known about the usability of such a Ternary Chord Keyboard (TCK) from previous experiments. Pilot tests indicated fast performance with a TCK.
Preliminary Physiological and Psychophysical Guidelines for Continuous Lifting Tasks
Authors: Genaidy Ashraf M. , Asfour Shihab S. , Khalil Tarek M.
Published: January 2009

The objective of this research was to study the effects of task parameters on physiological and psychophysical limits for prolonged lifting activities. The results of this study indicate that (1) The endurance time of individuals decreased with the increase of the frequency and the weight of load, and (2) physiological responses are dependent on lifting task parameters.