bluuebunny/crossref_metadata_2025 huggingface dataset:
Anthropometry of young competitive sport rock climbers
Authors: Watts P B , Joubert L M , Lish A K , Mast J D , Wilkins B
Published: September 2003

Background:Adult elite competitive rock climbers are small in stature with low body mass and very low body fat percentage. These characteristics have generated concern that young climbers may attempt body mass reduction to extreme levels with adverse consequences for health and performance. No published anthropometry data for young competitive climbers exist.

Objective:To describe the general anthropometric characteristics of junior US competitive rock climbers.

Methods:Ninety subjects (mean (SD) age 13.5 (3.0) years) volunteered to participate. All competed at the Junior Competition Climbers Association US National Championship. Anthropometric variables, including height, mass, body mass index (BMI), arm span, biiliocristal and biacromial breadths, skinfold thickness at nine anatomical sites, forearm and hand volumes, and handgrip strength, were measured. Selected variables were expressed as ratio values and as normative age and sex matched centile scores where appropriate. A control group (n = 45) of non-climbing children and youths who participated in a variety of sports activities, including basketball, cross country running, cross country skiing, soccer, and swimming, underwent the same testing procedures in the Exercise Science Laboratory of Northern Michigan University.

Results:Mean (SD) self reported climbing ability was 11.80 (1.20), or about 5.11d on the Yosemite decimal system scale. The mean (SD) experience level was 3.2 (1.9) years, and subjects competed in 10 (5) organised competitions over a 12 month period. Despite similarity in age, there were significant differences (p<0.01) between climbers and control subjects for height, mass, centile scores for height and mass, ratio of arm span to height (“ape index”), biiliocristal/biacromial ratio, sum of seven and sum of nine skinfolds, estimated body fat percentage, and handgrip/mass ratio. Despite significantly lower skinfold sums and estimated body fat percentage, no differences were found between climbers and controls for absolute BMI or BMI expressed as a centile score.

Conclusions:Young competitive climbers have similar general anthropometric characteristics to elite adult climbers. These include relatively small stature, low body mass, low sums of skinfolds, and high handgrip to mass ratio. Relative to age matched athletic non-climbers, climbers appear to be more linear in body type with narrow shoulders relative to hips. Differences in body composition exist between climbers and non-climbing athletes despite similar BMI values.
Follow up exercise studies in paediatric obesity: implications for long term effectiveness
Authors: Maziekas M T , LeMura L M , Stoddard N M , Kaercher S , Martucci T
Published: September 2003

Objectives:To examine the effects of exercise training on paediatric obesity immediately after training and at a one year follow up and to provide recommendations for future research.

Methods:Studies that met the following criteria were included in a meta-analysis: (a) at least six subjects per group; (b) subject groups consisting of children in the 4–17 year age range; (c) pre-test and post-test values for body composition; (d) used exercise such as walking, jogging, cycle ergometry, high repetition resistance exercise, and combinations; (e) training programmes lasting eight weeks or more; (f) full length publications; (g) apparently healthy children.

Results:A total of 135 studies of exercise as a method of treatment of paediatric obesity were located. Eight, containing 236 subjects, met our criteria for inclusion. Across all designs and categories, fixed effects modelling yielded significant decreases in the dependent variable percentage body fat immediately (0 = 1.04 (0.35); 95% confidence interval (CI) 0.41 to 1.6) and one year after the exercise intervention (0 = 0.84 (0.51); 95% CI 0.22 to 0.94). Forward stepwise linear regression suggested that the percentage body fat measured at the end of exercise training, exercise duration, and programme length accounted for 53–86% of the variance for percentage body fat at one year.

Conclusions:These data indicate that exercise is efficacious for reducing percentage body fat in obese children and adolescents, and that exercise intervention may encourage long term maintenance of the observed gains.
Evaluation of shoulder internal rotator muscle strength in baseball players with physical signs of glenohumeral joint instability
Authors: Falla D L , Hess S , Richardson C
Published: September 2003

Objectives:To identify whether subjects with glenohumeral translational instability present with a strength deficit in their internal rotator musculature, and therefore to determine if general strengthening exercises are warranted for the management of this condition.

Methods:Eighteen male baseball players were allocated to two groups on the basis of expert clinical evaluation of the presence (n = 8) or absence (n = 10) of shoulder translational instability. A strain gauge was used to calculate the force generated during maximal isometric internal rotation contractions in neutral shoulder rotation and 30° of internal rotation.

Results:The Mann-Whitney test identified no significant difference in force production during the maximum contractions in neutral rotation between the two subject groups. In the position of 30° shoulder internal rotation, subjects with glenohumeral translational instability produced significantly greater force than the control group (p<0.05).

Conclusions:High load strength testing cannot be used as a diagnostic tool to identify people with glenohumeral instability. Similarly, heavy resistance strengthening exercises for the internal rotator musculature are not warranted during rehabilitation.
Effects of strenuous exercise on haemostasis: Table 1
Authors: Smith J E
Published: September 2003

Objectives:To review the effects of exercise on haemostasis and examine the possible clinical sequelae of these changes.

Methods:The search strategy included articles from 1966 to August 2002 using Medline and SportDiscus databases, and cross referencing the bibliographies of relevant papers.

Results:Exercise results in activation of both the coagulation and fibrinolytic cascades, as shown by a reduction in whole blood clotting time and activated partial thromboplastin time, an increase in the activity of several components of the cascades, and an increase in fibrin degradation products. In vitro tests suggest that coagulation remains activated after fibrinolysis has returned to baseline levels.

Conclusions:Both the coagulation and fibrinolytic cascades are stimulated by strenuous exercise, but the temporal relation between the two and its clinical significance remains to be clarified. Doctors and athletes should be aware of the haemostatic changes induced by exercise, and further work is needed to clarify the possible role of these changes in sudden cardiac death.
Sex differences in whole body skeletal muscle mass measured by magnetic resonance imaging and its distribution in young Japanese adults
Authors: Abe T , Kearns C F , Fukunaga T
Published: September 2003

Objectives:To determine sex differences in the distribution of regional and total skeletal muscle (SM) using contiguous whole body magnetic resonance imaging (MRI) data, and to examine the relations between fat free mass (FFM) and total and regional SM masses.

Methods:A total of 20 Japanese college students (10 women and 10 men) volunteered for the study. FFM was measured by two compartment densitometry. Whole body MRI images were prepared using a 1.5 T scanner. Contiguous transverse images with 1.0 cm slice thickness were obtained from the first cervical vertebra to the ankle joints. All MRI scans were segmented into four components (SM, subcutaneous adipose tissue, bone, and residual tissues). In each slice, the SM tissue cross sectional areas (CSAs) were digitised, and the muscle tissue volume per slice was calculated by multiplying muscle CSA by slice thickness. SM volume units (litres) were converted into mass units (kg) by multiplying the volumes by the assumed constant density (1.041 mg/ml) for SM.

Results:The SM distribution pattern (shape of curve) from the contiguous whole body slices was essentially similar for the two sexes, with two large peaks and three smaller peaks (arms excluded). However, the largest peak was observed at the upper portion of the thigh for women and at the level of the shoulder for men. Men had larger (p<0.01) total and regional SM mass than women. All regional SM masses correlated highly (r= 0.90–0.99, p<0.01) with total SM mass. A strong positive correlation was observed between FFM and total and regional SM masses in both sexes (women,r= 0.95; men,r= 0.90; all p<0.01). As FFM increased, there was a corresponding increase in SM/FFM ratio for all subjects (r= 0.86, p<0.01).

Conclusions:Sex differences in total SM/FFM ratio and regional SM distributions are associated with the degree of absolute FFM accumulation in men and women.
Body position affects performance in untrained cyclists
Authors: Ashe M C , Scroop G C , Frisken P I , Amery C A , Wilkins M A , Khan K M
Published: September 2003

Objective:To compare cardiovascular and ventilatory variables in upright versus aero cycle ergometry at submaximal and maximal exercise intensities in untrained cyclists.

Method:Ten physically active men (mean (SD) age 19.1 (1.10) years) who were unfamiliar with aerobars underwent maximal exercise testing and steady state cycling at 50, 100, and 150 W.

Results:Participants had significantly greater maxima for oxygen uptake (Vo2), ventilation, heart rate, and workload maximum in the upright position. During steady state cycling at the three workloads, Vo2(ml/kg/min) and gross mechanical efficiency were significantly greater in the upright position.

Conclusions:In untrained subjects performing with maximal effort, the upright position permits greater Vo2, ventilation, heart rate, and workload maxima. Further, in the steady state, exercise cycling may be less costly in the upright position. For this reason, untrained cyclists need to weigh body position effects against the well known aerodynamic advantages of the aero position.
Physical activity energy expenditure measured using a portable telemetric device in comparison with a mass spectrometer: Table 1
Authors: Maiolo C , Melchiorri G , Iacopino L , Masala S , De Lorenzo A
Published: September 2003

Background:Several studies have evaluated the accuracy of portable metabolic gas analysis systems, which measure physical activity energy expenditure. Since the Cosmed K2 telemetric system, two K4 devices (RQ and b2) have been developed.

Objective:To compare measurements using the Cosmed K4 RQ with measurements by a traditional method (mass spectrometer) for a sample of healthy subjects performing physical exercise of various intensities.

Methods:Nine healthy male footballers (mean (SD) age 18.3 (2.2) years) performed an incremental exercise running test from 8 km/h to exhaustion, with an increase of 2 km/h for each level of the test protocol. The expired air was collected simultaneously using the Cosmed K4 RQ and Airspec QP9000 mass spectrometer. Oxygen consumption (Vo2) and carbon dioxide production (Vco2) were measured at rest and at each exercise intensity.

Results:No significant differences were found between Vo2and Vco2measured by the two instruments, at rest or during exercise.

Conclusions:The application of the Cosmed K4 RQ system for Vo2and Vco2measurements at rest and during both submaximal and maximal exercise may be of interest to sport physiologists, nutritionists, and doctors.
A 16 year study of injuries to professional kickboxers in the state of Victoria, Australia
Authors: Zazryn T R , Finch C F , McCrory P
Published: September 2003

Objectives:To determine the rate and type of injuries occurring to registered professional kickboxers in Victoria, Australia over a 16 year period.

Methods:Data describing all fight outcomes and injuries sustained during competition for the period August 1985 to August 2001 were obtained from the Victorian Professional Boxing and Combat Sports Board.

Results:A total of 382 injuries were recorded from 3481 fight participations, at an injury rate of 109.7 injuries per 1000 fight participations. The most common body region injured was the head/neck/face (52.5%), followed by the lower extremities (39.8%). Specifically, injuries to the lower leg (23.3%), the face (19.4%), and intracranial injury (17.2%) were the most common. Over 64% of the injuries were superficial bruising or lacerations.

Conclusion:The nature of kickboxing, whereby kicking the opponent is the prime movement and the head a prime target, is reflected in the distributions of body regions most commonly injured by participants. Further research into injury patterns in different styles of kickboxing and the mechanism of injury occurrence is required. Exposure adjusted prospective studies are needed to monitor injury rates over time.
Chronic compartment syndrome of the forearm in competitive motor cyclists: a report of two cases
Authors: Goubier J N , Saillant G
Published: September 2003

Exertional compartment syndrome of the forearm is rare. However, it should be considered in cases of a painful forearm during motorcycle racing. Pressure measurements of all compartments during exercises that simulate the actions of racing confirm the diagnosis. An exertional electromyography may be useful to reveal a nerve compression associated with the compartment syndrome. Fasciotomy of the affected compartments allows relief of symptoms and return to previous activities in all cases.
Exercise induced critical ischaemia of the upper limb secondary to a cervical rib
Authors: Casey R G , Richards S , O’Donohoe M
Published: September 2003

The case is reported of a 32 year old woman with acute on chronic upper limb ischaemia due to thrombus from a cervical rib that had compressed the right subclavian artery of her dominant hand after use of a rowing machine. If not detected early, this condition can be debilitating especially in the young. A multidisciplinary approach is advisable to ensure a satisfactory outcome.
Giro, Tour, and Vuelta in the same season
Authors: Lucia A , Hoyos J , Santalla A , Earnest C P , Chicharro J L
Published: September 2003

The exercise volume and intensity are reported of a male professional cyclist (age 30; Vo2max 75.0 ml/kg/min) who successfully completed the 2001 Giro d’Italia (May), Tour de France (July), and Vuelta a España (September). The total exercise time during the Giro, Tour, and Vuelta was 90 hours 44 minutes (5444 minutes), 88 hours 23 minutes (5303 minutes), and 72 hours 59 minutes (4379 minutes) respectively. Heart rate telemetry during the races allowed the exercise intensity to be classified into three phases: I, below the first ventilatory threshold (VT1); II, between VT1 and the second ventilatory threshold (VT2); III, above VT2. Compared with the Giro and Tour, the lower exercise volume of the Vuelta (about 20% less total time) was compensated for by a considerably lower and higher contribution of phases I and III respectively. As a result, the total load (volume × intensity) in the three races was comparable.
Accidental carotid artery injury caused by a horse rope
Authors: Nunnink L , Abu-Zidan F
Published: September 2003

A 37 year old woman who had bred horses for more than 20 years was leading two horses in a horse corral. One horse bolted and the lead rope wrapped around her neck. Four hours after the accident, she developed sudden aphasia, right facial palsy, and right arm weakness. Conventional and magnetic resonance angiography showed complete traumatic occlusion of the left common carotid artery due to thrombosis at the C6/7 level. There was good collateral flow from the other side. The patient was maintained on heparin followed by warfarin and recovered completely by the third day. This case shows the importance of suspecting vascular injury and thrombosis after trauma to sites of major vessels.
The hp version of Eulerian‐Lagrangian mixed discontinuous finite element methods for advection‐diffusion problems
Authors: Chen Hongsen , Chen Zhangxin , Li Baoyan
Published: September 2003

We study the hp version of three families of
Eulerian‐Lagrangian mixed discontinuous finite element (MDFE)
methods for the numerical solution of advection‐diffusion
problems. These methods are based on a space‐time mixed
formulation of the advection‐diffusion problems. In space, they
use discontinuous finite elements, and in time they approximately
follow the Lagrangian flow paths (i.e., the hyperbolic part of
the problems). Boundary conditions are incorporated in a natural
and mass conservative manner. In fact, these methods are locally
conservative. The analysis of this paper focuses on
advection‐diffusion problems in one space dimension. Error
estimates are explicitly obtained in the grid size h, the polynomial degree p, and the solution regularity; arbitrary
space grids and polynomial degree are allowed. These estimates are
asymptotically optimal in both h and p for some of these
methods. Numerical results to show convergence rates in h and
p of the Eulerian‐Lagrangian MDFE methods are presented. They
are in a good agreement with the theory.
Applications of one‐ and two‐dimensionalVolterra inequalities in differential equations of thehyperbolic type
Authors: Hącia Lechosław
Published: September 2003

Some variants of one‐dimensional and two‐dimensional integral
inequalities of the Volterra type are applied to study the
behaviour properties of the solutions to various boundary value
problems for partial differential equations of the
hyperbolic type. Moreover, new types of integral inequalities for
one and two variables, being a generalization of the Gronwall
inequality, are presented and used in the theory of nonlinear
hyperbolic differential equations.
Separately continuous functions: approximations, extensions, and restrictions
Authors: Piotrowski Zbigniew , Vallin Robert W.
Published: September 2003

A function f(x, y) is separately continuous if at any point the
restricted functions fx(y) and fy(x) are continuous as
functions of one variable. In this paper, we use several results
which have been obtained for other generalized continuities and
apply them to functions which are separately
continuous.
On Markovian cocycle perturbations in classical and quantum probability
Authors: Amosov G. G.
Published: September 2003

We introduce Markovian cocycle perturbations of the groups of
transformations associated with classical and quantum stochastic
processes with stationary increments, which are characterized by
a localization of the perturbation to the algebra of events of
the past. The Markovian cocycle perturbations of the Kolmogorov
flows associated with the classical and quantum noises result in
the perturbed group of transformations which can be decomposed
into the sum of two parts. One part in the decomposition is
associated with a deterministic stochastic process lying in the
past of the initial process, while another part is associated with
the noise isomorphic to the initial one. This construction can
be considered as some analog of the Wold decomposition for
classical stationary processes excluding a nondeterministic part
of the process in the case of the stationary quantum stochastic
processes on the von Neumann factors which are the Markovian
perturbations of the quantum noises. For the classical stochastic
process with noncorrelated increments, the model of Markovian
perturbations describing all Markovian cocycles up to a unitary
equivalence of the perturbations has been constructed. Using this
model, we construct Markovian cocycles transforming the Gaussian
state ρ to the Gaussian states equivalent to ρ.
Some versions of Anderson′s and Maher′s inequalities II
Authors: Mecheri Salah
Published: September 2003

We are interested in the investigation of the orthogonality (in
the sense of Birkhoff) of the range of an elementary operator and
its kernel.
Recent applications of fractional calculus to science and engineering
Authors: Debnath Lokenath
Published: September 2003

This paper deals with recent applications of fractional calculus
to dynamical systems in control theory, electrical circuits with
fractance, generalized voltage divider, viscoelasticity,
fractional‐order multipoles in electromagnetism, electrochemistry, tracer in fluid flows, and model of neurons
in biology. Special attention is given to numerical computation of
fractional derivatives and integrals.
On unsteady two‐phase fluid flow due to eccentric rotation of a disk
Authors: Ghosh A. K. , Paul S. , Debnath L.
Published: September 2003

We examine the unsteady flow of a two‐phase fluid generated by
the nontorsional oscillations of a disk when the disk and the
fluid at infinity rotate noncoaxially with the same angular
velocity. The solutions are obtained for both the fluid and the
particle velocities in closed form. It is found that the
solutions remain valid for all values of the frequency of
oscillations of the disk including the resonant frequency, which
is equal to the angular velocity of rotation. But, in absence of
particles, only in the case of resonance no oscillatory solution
is possible, which is similar to that of solid‐body rotation as
pointed out by Thornley (1968). It is also shown that, unlike
the case of single‐disk configuration, no unique solution exists
in a double‐disk configuration, a result which is the reverse to that of solid‐body rotation. Finally, the results are presented graphically to determine the quantitative response of the particle on the flow.
Eigenfrequencies of generally restrained beams
Authors: Grossi Ricardo Oscar , Albarracín Carlos Marcelo
Published: September 2003

We deal with the exact determination of eigenfrequencies of a
beam with intermediate elastic constraints and generally
restrained ends. It is the purpose of this paper to use the
calculus of variations to obtain the equations of motion and the
natural boundary conditions, and particularly those at the
intermediate constraints. Numerical values for the first five
natural frequencies are presented in a tabular form for a wide
range of values of the restraint parameters. Several particular
cases are presented and some of these cases have been compared
with those available in the literature.
On initial boundary value problem with Dirichlet integralconditions for a hyperbolic equation with the Besseloperator
Authors: Bouziani Abdelfatah
Published: September 2003

We consider a mixed problem with Dirichlet and integral
conditions for a second‐order hyperbolic equation with the Bessel
operator. The existence, uniqueness, and continuous dependence of
a strongly generalized solution are proved. The proof is based on
an a priori estimate established in weighted Sobolev spaces and
on the density of the range of the operator corresponding to the
abstract formulation of the considered problem.
On the minimization of some nonconvex double obstacle problems
Authors: Elfanni A.
Published: September 2003

We consider a nonconvex variational problem for which the set of
admissible functions consists of all Lipschitz functions located
between two fixed obstacles. It turns out that the value of the
minimization problem at hand is equal to zero when the obstacles
do not touch each other; otherwise, it might be positive. The
results are obtained through the construction of suitable
minimizing sequences. Interpolating these minimizing sequences in
some discrete space, a numerical analysis is then carried out.
Convergence of a short‐step primal‐dual algorithm based on the Gauss‐Newton direction
Authors: Kruk Serge , Wolkowicz Henry
Published: September 2003

We prove the theoretical convergence of a short‐step, approximate
path‐following, interior‐point primal‐dual algorithm for
semidefinite programs based on the Gauss‐Newton direction
obtained from minimizing the norm of the perturbed optimality
conditions. This is the first proof of convergence for the
Gauss‐Newton direction in this context. It assumes strict
complementarity and uniqueness of the optimal solution as well as
an estimate of the smallest singular value of the Jacobian.
Reflections on Real Presence by a Virtual Person
Authors: Heeter Carrie
Published: September 2003

I have lived in San Francisco while working as a full-time virtual faculty member for Michigan State University for nearly six years. Unlike most humans, I spend a larger proportion of every day as a virtual person than as a physical person. This article is adapted from a keynote speech I delivered at the Fourth International Workshop on Presence in Philadelphia in May of 2001. I use a personal narrative style to explore issues and to question some of the research community's prevailing assumptions about presence.

Lombard and Ditton's (1997) frequently cited conceptualization defines presence as a “perceptual illusion of nonmediation” that occurs “when a person fails to perceive or acknowledge the existence of a medium in his/her communication environment and responds as he/she would if the medium were not there.” The underlying assumption is that, in the absence of technology, everyone experiences continuous presence at a constant intensity throughout their lives.

Instead, this article suggests that presence is not a constant of everyday nonmediated experience. Careful consideration of unmediated (real) presence might help the conceptualization and study of mediated presence.
Media Psychology “is not yet there”: Introducing Theories on Media Entertainment to the Presence Debate
Authors: Klimmt Christoph , Vorderer Peter
Published: September 2003

Contemporary theoretical explications of presence experiences can be advanced and completed by integrating theoretical frameworks from media psychology. This article briefly presents concepts related to media entertainment that have been elaborated and/or applied by media psychologists and that exhibit considerable overlaps with the explication of presence. Specifically, the concept of involvement (Vorderer, 1992), affective disposition theory (Zillmann, 1996), simulation theory (Oatley, 1994), and the psychological theory of play (Oerter, 1999) are introduced. For each framework, connection points to the theoretical conceptualization of presence are pointed out. The article illuminates new opportunities for interdisciplinary cooperation in advancing our understanding of presence.
Virtual Laboratories: Comparability of Real and Virtual Environments for Environmental Psychology
Authors: Kort Yvonne A. W. de , IJsselsteijn Wijnand A. , Kooijman Jolien , Schuurmans Yvon
Published: September 2003

Virtual environments have the potential to become important new research tools in environment behavior research. They could even become the future (virtual) laboratories, if reactions of people to virtual environments are similar to those in real environments. The present study is an exploration of the comparability of research findings in real and virtual environments. In the study, 101 participants explored an identical space, either in reality or in a computer-simulated environment. Additionally, the presence of plants in the space was manipulated, resulting in a 2 (environment)× 2 (plants) between-subjects design. Employing a broad set of measurements, we found mixed results. Performances on size estimations and a cognitive mapping task were significantly better in the real environment. Factor analyses of bipolar adjectives indicated that, although four dimensions were similar for both environments, a fifth dimension of environmental assessment—termedarousal—was absent in the virtual environment. In addition, we found significant differences on the scores of four of the scales. However, no significant interactions appeared between environment and plants. Experience of and behavior in virtual environments have similarities to that in real environments, but there are important differences as well. We conclude that this is not only a necessary, but also a very interesting research subject for environmental psychology.
Designing for Presence and Performance: The Case of the Virtual Fish Tank
Authors: Shim Wooyoung , Kim Gerard Jounghyun
Published: September 2003

Although much research work has focused on identifying different factors that affect presence, it is still not clear how to effectively combine these results to create a content with high presence with respect to a given hardware set-up and limited computing resources. This paper proposes a concept of level of presence (LOP) in which we attempt to select a set of presence elements and their levels to maximize their “contribution” toward the overall presence subject to system resources. Such an optimization scheme would require a reasonable characterization of the computational costs and a sufficient knowledge of the relative and collective merits of various presence elements. We made an attempt to apply the LOP concept to VR system design for a particular application, a virtual fish tank. The purpose of this study is to assess the usefulness of the LOP concept and introduce science into content creation. We selected two important presence elements—the field of view (FOV) and the simulation level of detail (SLOD)—and quantified their costs in terms of the required computation time. Next, we ran a simple experiment to quantify the relative benefits of those two presence factors. For this application, it was found that providing more lifelike simulation, for instance, incurred needlessly expensive computations compared to the amount of increased benefits. Based on the result, the virtual fish tank was configured with the appropriate FOV and SLOD for maximum presence under different conditions, such as the preferred frame rate and total number of objects. We discuss the merits of such a presence-driven VR system development approach.
Movement Behavior for Soldier Agents on a Virtual Battlefield
Authors: Reece Douglas A.
Published: September 2003

We have developed a movement behavior model for soldier agents who populate a virtual battlefield environment. Whereas many simulations have addressed human movement behavior before, none of them has comprehensively addressed realistic military movement at individual and unit levels. To design an appropriate movement behavior model, we found it necessary to elaborate all of the requirements on movement from the military tasks of interest, define a behavior architecture that encompasses all required movement tasks, select appropriate movement planning and control approaches in light of the requirements, and implement the planning and control algorithms with novel enhancements to achieve satisfactory results.

The breadth of requirements in this problem domain makes simple behavior architectures inadequate and prevents any single planning approach from easily accomplishing all tasks. In our behavior architecture, a hierarchy of tasks is distributed over unit leaders and unit members. For movement planning, we use an A* search algorithm on a hybrid search space comprising a two-dimensional regular grid and a topological map; the plan produced is a series of waypoints annotated with posture and speed changes. Individuals control movement with reactive steering behaviors. The result is a system that can realistically plan and execute a variety of unit and individual agent movement tasks on a virtual battlefield.
Real Handball Goalkeeper vs. Virtual Handball Thrower
Authors: Bideau Benoit , Kulpa Richard , Ménardais Stéphane , Fradet Laetitia , Multon Franck , Delamarche Paul , Arnaldi Bruno
Published: September 2003

Virtual reality offers new tools for human motion understanding. Several applications have been widely used in teleoperation, military training, driving and flying simulators, and so forth. We propose to test if virtual reality is a valid training tool for the game of handball. We focused on the duel between a handball goalkeeper and a thrower. To this end, we defined a pilot experiment divided into two steps: an experiment with real subjects and another one with virtual throwers. The throwers' motions were captured in order to animate their avatar in a reality center. In this paper, we focused on the evaluation of presence when a goalkeeper is confronting these avatars. To this end, we compared the goalkeeper's gestures in the real and in the virtual experiment to determine if virtual reality engendered the same movements for the same throw. Our results show that gestures did not differ between the real and virtual environment. As a consequence, we can say that the virtual environment offered enough realism to initiate natural gestures. Moreover, as in real games, we observed the goalkeeper's anticipation to allow us to use virtual reality in future work as a way to understand the goalkeeper and thrower interactions. The main originality of this work was to measure presence in a sporting application with new evaluation methods based on motion capture.
Progress and Prospects for the Development of Computer-Generated Actors for Military Simulation: Part 2—Reasoning System Architectures and Human Behavior Modeling
Authors: Banks Sheila B. , Stytz Martin R.
Published: September 2003

The development of computer-generated synthetic environments, also calleddistributed virtual environments (DVEs), relies heavily upon computer-generated actors (CGAs) to provide accurate behaviors at reasonable cost so that the synthetic environments are useful, affordable, complex, and realistic. Unfortunately, the pace of synthetic environment development and the level of desired CGA performance continue to rise at a much faster rate than CGA capability improvements. This insatiable demand for realism in CGAs for synthetic environments arises from the growing understanding of the significant role that modeling and simulation can play in a variety of uses. These uses include training, analysis, procurement decisions, mission rehearsal, doctrine development, force-level and task-level training, information assurance, cyberwarfare, force structure analysis, sustainability analysis, life cycle costs analysis, material management, infrastructure analysis, and many other uses. In these and other uses of military synthetic environments, computergenerated actors play a central role because they have the potential to increase the realism of the environment while also reducing the cost of operating the environment. The progress made in addressing the technical challenges that must be overcome to realize effective and realistic CGAs for military simulation environments and the technical areas that should be the focus of future work are the subject of this series of papers, which surveys the technologies and progress made in the construction and use of CGAs. In this, the second installment of three papers in the series, we present a discussion of CGA software architectures and a discussion of approaches to human behavior modeling.
Artificial Fish Schools: Collective Effects of School Size, Body Size, and Body Form
Authors: Kunz Hanspeter , Hemelrijk Charlotte K.
Published: September 2003

Individual-based models of schooling in fish have demonstrated that, via processes of self-organization, artificial fish may school in the absence of a leader or external stimuli, using local information only. We study for the first time how body size and body form of artificial fish affect school formation in such a model. For a variety of group sizes we describe how school characteristics (i.e., group form, spread, density, polarization, turning rate, and speed) depend on body characteristics. Furthermore, we demonstrate that the nearest neighbor distance and turning rate of individuals are different for different regions in the group, although the agents are completely identical. Our approach shows the significance of both self-organization and embodiment in modeling of schools of artificial fish and, probably, in structuring schools of real fish.
Evolving Mobile Robots Able to Display Collective Behaviors
Authors: Baldassarre Gianluca , Nolfi Stefano , Parisi Domenico
Published: September 2003

We present a set of experiments in which simulated robots are evolved for the ability to aggregate and move together toward a light target. By developing and using quantitative indexes that capture the structural properties of the emerged formations, we show that evolved individuals display interesting behavioral patterns in which groups of robots act as a single unit. Moreover, evolved groups of robots with identical controllers display primitive forms of situated specialization and play different behavioral functions within the group according to the circumstances. Overall, the results presented in the article demonstrate that evolutionary techniques, by exploiting the self-organizing behavioral properties that emerge from the interactions between the robots and between the robots and the environment, are a powerful method for synthesizing collective behavior.
Bridging Nonliving and Living Matter
Authors: Rasmussen Steen , Chen Liaohai , Nilsson Martin , Abe Shigeaki
Published: September 2003

Assembling non-biological materials (geomaterials) into a proto-organism constitutes a bridge between nonliving and living matter. In this article we present a simple step-by-step route to assemble a proto-organism. Many pictures have been proposed to describe this transition within the origins-of-life and artificial life communities, and more recently alternative pictures have been emerging from advances in nanoscience and biotechnology. The proposed proto-organism lends itself to both traditions and defines a new picture based on a simple idea: Given a set of required functionalities, minimize the physicochemical structures that support these functionalities, and make sure that all structures self-assemble and mutually enhance each other's existence. The result is the first concrete, rational design of a simple physicochemical system that integrates the key functionalities in a thermodynamically favorable manner as a lipid aggregate integrates proto-genes and a proto-metabolism. Under external pumping of free energy, the metabolic processes produce the required building blocks, and only specific gene sequences enhance the metabolic kinetics sufficiently for the whole system to survive. We propose an experimental implementation of the proto-organism with a discussion of our experimental results, together with relevant results produced by other experimental groups, and we specify what is still missing experimentally. Identifying the missing steps is just as important as providing the road map for the transition. We derive the kinetic and thermodynamic conditions of each of the proto-organism subsystems together with relevant theoretical and computational results about these subsystems. We present and discuss detailed 3D simulations of the lipid aggregation processes. From the reaction kinetics we derive analytical aggregate size distributions, and derive key properties of the metabolic efficiency and stability. Thermodynamics and kinetics of the ligation directed self-replication of the proto-genes is discussed, and we summarize the full life cycle of the proto-organism by comparing size, replication time, and energy with the biomass efficiency of contemporary unicells. Finally, we also compare our proto-organism picture with existing origins-of-life and protocell pictures.

By assembling one possible bridge between nonliving and living matter we hope to provide a piece in the ancient puzzle about who we are and where we come from.
Selective Instability: Maternal Effort and the Evolution of Gene Activation and Deactivation Rates
Authors: Maley Carlo C. , Tapscott Stephen J.
Published: September 2003

We previously used simulations of gene expression to demonstrate that rapid activation and deactivation rates stabilized outcomes in stochastic systems. We hypothesized that transient single allele inactivation of an autosomal gene during gametogenesis or very early embryogenesis could have a selective advantage if it permits the functional sampling of each allele and precludes committing maternal effort to an embryo with a deleterious mutation. To test this hypothesis, we simulated the evolution of gene expression activation and deactivation rates and imposed two different selective pressures on the populations: (a) late selection against individuals that cannot maintain a threshold level of gene product that occurs after the investment of maternal effort (i.e., after birth); or (b) early selection: in addition to late selection, maintenance of the gene product above a threshold level was necessary for early development prior to commitment of maternal effort. We found that the opportunity to save reproductive effort from early selection caused the evolution of higher deactivation rates and lower activation rates than in the late selection condition. Thus, we predict that in the special case where early selection can save maternal investment in non-viable offspring, gene expression activation rates and deactivation rates might be selected to permit sampling of the product from each allele.
Viscous Populations and Their Support for Reciprocal Cooperation
Authors: Marshall James A. R. , Rowe Jonathan E.
Published: September 2003

Viscous populations (those whose members are spatially distributed and have limited mobility and locality of interaction and mating) have been proposed to support the evolution of reciprocal cooperation among self-interested individuals. Here we present a model of such a population and describe how its examination yielded the realization that different classes of viscous populations exist with differing levels of support for reciprocal cooperation. Specifically we find from our model that, in a spatially distributed population with increased viscosity, the reciprocally cooperative tit-for-tat strategy may not be globally stable due to a corresponding increase in local population density.
Frog and Cyberfrog are Friends: Dissection Simulation and Animal Advocacy
Authors: Fleischmann Kenneth
Published: September 2003

Although at first glance it may seem an unlikely alliance, frogs and cyberfrogs certainly benefit from an unusual friendship that connects the virtual world of dissection simulation and the physical realm of nonhuman animal advocacy.This paper focuses on the symbiotic relationship of dissection simulation designers and animal advocates. Dissection simulation manufacturers benefit from this relationship through the purchasing and promotion of their products by animal advocacy organizations, and also they benefit from policy changes that encourage the use of dissection simulations as alternatives to dissection. Reciprocally,animal advocacy organizations benefit by saving animal lives, gaining a new tool for convincing teachers to stop dissecting, and demonstrating that they are a pro-technology movement. The knowledges and values embedded in cyberfrogs make them both boundary objects and cyborgs.
"What a Thing, then, is this Cow...": Positioning Domestic Livestock Animals in the Texts and Practices of Small-Scale "Self-Sufficiency"
Authors: Holloway Lewis
Published: September 2003

This paper focuses on the positioning of animals other than human in the texts and practices of two versions of small-scale food "self-sufficiency" in Britain. The paper discusses the writings of Cobbett (1822/1926, 1830/1985) and Seymour (1960s/1970s) on self-sufficiency, suggesting that livestock animals are central, in a number of ways, to the constitution of these modes of self-sufficiency. First, animals are situated in both the texts and in the practicing of self-sufficiency regarded as essential parts of the economies and ecologies of small-scale food production. Second, animals' parts in these authors' criticisms of wider social, economic and political conditions supplement their role in small-scale domestic food supply. Animals become associated with a morality of human behavior and lifestyle and are part of the broader social critiques that the writing and practicing of these modes of self-sufficiency imply. These historically and geographically specific versions of self-sufficiency are valuable in defining and enacting possible alternative modes of human-animal relation in the context of food production.
The Moral Reasoning of Believers in Animal Rights
Authors: Block Gary
Published: September 2003

This study evaluated the moral reasoning of 54 individuals who believed in the concept of nonhuman animal rights using a research tool based on Kohlberg's (1986) cognitive theory of moral development. Results for these primarily college and postgraduate-educated individuals suggest that people who believe in animal rights have equivalent or higher-level moral reasoning when compared to adult, education-matched, historical control groups.
Beyond Dominance and Affection: Living with Rabbits in Post-Humanist Households
Authors: Smith Julie Ann
Published: September 2003

Nearly 20 years age, Yi-Fu Tuan wrote his influential Dominance and Affection:The Making of Pets (1984), which argued that human affection for domestic animals is inseparable from dominance. Today, cultural critics persist in the view that companion animals are compromised, even degraded, because they are controlled by humans. The essay attempts to rethink the relationship between humans and companion animals beyond the freedom-dominance binary. It argues for a conceptual approach that defers confidant interpretation of animals while dramatically relaxing control of them within human settings. It suggests that this approach be called a "performance ethic" and offered the House Rabbit Society as a model.
Description and development of Gastromermis anisotis sp. n. (Nematoda: Mermithidae), a parasite in a quadritrophic system involving a cyanobacterium, midge and virus
Authors: Poinar Roberta , Poinar George
Published: September 2003

This paper reports the results of a 25 year study on an obligate quadritrophic system involving a midge, Cricotopus nostocicola (Diptera: Chironomidae), its cyanobacterial food source, Nostoc parmeliodes (Nostocales), a new species of nematode parasite of the midge, Gastromermis anisotis sp. n. (Mermithidae), and a virus infecting the nematode. Occurring in a mountain stream in California, the components of this system are adapted for survival at temperatures just above freezing (4-8°C). Developmental studies of the nematode include mating, oviposition, egg hatch, host penetration, parasitic development, free-living habits, spermatogenesis, platelet structure, and virus infection. Rates of parasitism varied between 5-42% over the 25 year period. The nematode was considered to be the most significant biological control agent of Cricotopus populations in the stream.
Lysosomal and pseudocoelom routing protects Caenorhabditis elegans from ricin toxicity
Authors: Coomans August , Claeys Myriam , Borgonie Gaëtan , Link Christopher
Published: September 2003

The resistance of the nematode Caenorhabditis elegans towards the highly potent toxin ricin has been studied. Incubation of C. elegans in ricin did not affect life span or progeny production. However, micro-injection of the ricin A-chain into the distal, syncitial gonad caused degeneration and sterility in test specimens, confirming that C. elegans ribosomes are sensitive. Using transmission electron microscopy, it was observed that ricin is effectively internalised into the intestinal cells. When pre-labelled with gold, the toxin reached only the lysosomes. When native toxin was used, the toxin was either routed to the lysosomes or underwent transcytosis to the pseudocoelomatic cavity and incorporation into embryos. None of the ricin reached either the trans Golgi network or the Golgi apparatus, considered essential for toxicity. The observed oral non-toxicity is therefore due to alternate sorting of the toxin, a mechanism not previously observed. The data indicate that, although ricin can opportunistically bind to, and be internalised by, cell surface receptors, these receptors are not sufficient to elicit toxicity.