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PubMed2005

A systemic model of the youth mentoring intervention.

Conceptual and empirical work on youth mentoring naturally tends to focus on the relationship between mentor and child. However, the parent/guardian and agency caseworker also may contribute to the success or failure of the mentoring intervention, and program effects may be partially mediated by the child's interactions with these individuals. This article presents a systemic model of mentoring depicting the interdependent network of relationships established between mentor, child, parent/guardian, and caseworker against the backdrop of agency policies and procedures. Numerous examples illustrate pathways of influence and patterns of communication in the context of this more holistic model of mentoring. Editors' Strategic Implications: Drawing upon ecological and systems theories, the author provides a promising conceptual model that focuses on patterns of interpersonal exchange among several key individuals (but not the only possible ones). This model reminds researchers and practitioners that mentoring resides within a mutually reinforcing (or inhibiting) network of other relationships. This systemic thinking has implications for child welfare agency policies and practices.

Adolescent↗
PubMed2005

Developmental psychology and public policy: progress and prospects.

This article outlines a framework for developmentally oriented policy research. Drawing from U. Bronfenbrenner's (1995) dynamic developmental systems theory, the authors suggest ways in which the key tenets of process, persons, context, and time can inform policy research in developmental psychology and can be used to support a causal interpretation of the results of those analyses. Conceptualizing public policies from a dynamic developmental systems perspective has a variety of implications for future research, and this article considers some of these implications.

Adolescent↗
PubMed1989

[Is it possible to have a medical definition of family crisis?].

In our contemporary society, the traditional multi-generational family has to adapt and to organize itself around a smaller nucleus: "The nuclear family". Nowadays, the management of the crises which accompany significant Life Events (such as birth, marriage, retirement, death...) within this new family-system, is refrained by the lack of "relays" which were previously provided by the "enlarged family". In the absence of available relatives (that is, grandparents, cousins, etc...), it is now the Medical System which is addressed with the demand for help. Using worthy contributions of the systemic theories, the authors analyze the ambiguity of such a request and the paradox underlying it, namely, to take care of a "normal" family crisis. They emphasize two major dangers consisting of the "designation" of an identified patient and the risk of "phagocytosis" of the therapeutic system by the family system.

Adaptation, Psychological↗
PubMed2003

Practical applications of chaos theory to the modulation of human ageing: nature prefers chaos to regularity.

From time to time, novel ways of interpreting and modifying ageing mechanisms are proposed. Occasionally, these lead to a conceptual dead end, whereas at other times new and vital insights into basic ageing mechanisms are gained. This review concentrates on one such way of interpreting and manipulating ageing processes, based on chaos (dynamical systems) theory. One prediction of this theory is that a wide-ranging loss of physiological complexity from molecular to cellular, and from tissue to organismic levels accompanies ageing and age-related diseases. Although this view has been criticised, and arguments have been put forward to claim that there is also an increase of complexity during ageing and dysfunction, this review holds that the interpretation of ageing as a simplification of physiological dynamical complexity offers clear advantages. Ageing changes can be quantified and the results of treatment monitored. Clinical benefits can be predicted and intervention strategies improved. Two main practical suggestions for achieving successful ageing at the clinical level are examined. First, chaos theory challenges the traditional pharmacological regimes and implies that, for maximum benefit, medication aimed at modifying some of the signs of ageing should be given at irregular, pulsed or multiple intervals, and at constantly changing dosage strengths. Second, for preventing age-related disability, it is necessary to introduce and maintain a multiplicity of external and internal physiological stimuli, such as variable physical and mental exercise regimes.

Aging↗
PubMed2005

Pattern computation in neural communication systems.

Biological data suggests that activity patterns emerging in small- and large-scale neural systems may play an important role in performing the functions of the neural system, and in particular, neural computations. It is proposed in this paper that neural systems can be understood in terms of pattern computation and abstract communication systems theory. It is shown that analysing high-resolution surface EEG data, it is possible to determine abstract probabilistic rules that describe how emerging activity patterns follow earlier activity patterns. The results indicate the applicability of the proposed approach for understanding the working of complex neural systems.

Animals↗
PubMed2004

A systems-based food safety evaluation: an experimental approach.

Food establishments are complex systems with inputs, subsystems, underlying forces that affect the system, outputs, and feedback. Building on past exploration of the hazard analysis critical control point concept and Ludwig von Bertalanffy General Systems Theory, the National Park Service (NPS) is attempting to translate these ideas into a realistic field assessment of food service establishments and to use information gathered by these methods in efforts to improve food safety. Over the course of the last two years, an experimental systems-based methodology has been drafted, developed, and tested by the NPS Public Health Program. This methodology is described in this paper.

Federal Government↗
PubMedDate not supplied

Looking around: 35 years of oculomotor modeling.

Eye movements have attracted an unusually large number of researchers from many disparate fields, especially over the past 35 years. The lure of this system stemmed from its apparent simplicity of description, measurement, and analysis, as well as the promise of providing a "window in the mind." Investigators in areas ranging from biological control systems and neurological diagnosis to applications in advertising and flight simulation expected eye movements to provide clear indicators of what the sensory-motor system was accomplishing and what the brain found to be of interest. The parallels between compensatory eye movements and perception of spatial orientation have been a subject for active study in visual-vestibular interaction, where substantial knowledge has accumulated through experiments largely guided by the challenge of proving or disproving model predictions. Even though oculomotor control has arguably benefited more from systems theory than any other branch of motor control, many of the original goals remain largely unfulfilled. This paper considers some of the promising potential benefits of eye movement research and compares accomplishments with anticipated results. Four topics are considered in greater detail: (i) the definition of oculomotor system input and output, (ii) optimization of the eye movement system, (iii) the relationship between compensatory eye movements and spatial orientation through the "internal model," and (iv) the significance of eye movements as measured in (outer) space.

Aerospace Medicine↗
PubMed1981

The research-defining accident investigation methodology of the National Institute for Occupational Safety and Health.

The Accident Investigation Methodology (AIM), developed for the National Institute for Occupational Safety and Health through a contract effort by Safety Sciences of San Diego, California, is a composite procedure utilizing many useful concepts and approaches from existing investigative techniques in addition to innovations. The investigation procedure is oriented toward the identification of occupational accident/injury countermeasures and associated research needs. Emphasis is placed upon modern "systems theory," which considers human factors as a primarily intended for knowledgeable safety practitioners with some previous experience. Interviewing techniques and preparations for conducting an investigation are thoroughly addressed. The necessary tools and forms for actual investigation are included, as well as a sophisticated analysis procedure and coding system for the computer accessing of all relevant data.

Accidents, Occupational↗
PubMed1997

Early organization of the nonlinear right brain and development of a predisposition to psychiatric disorders.

The concepts of self-organization, state changes, and energy flow are central to dynamic systems theory. In this work 1 suggest that to apply these general principles to the study of normal and abnormal development, these constructs must be specifically defined in reference to current knowledge of brain development. Toward that end, I present an overview of the properties of self-organizing developmental systems, and then propose a model of attachment dynamics as synchronized energy exchanges that cocreate nonlinear changes of state, discuss the roles of bioamines and energy-generating brain mitochondria in state regulation, and describe the energy-dependent imprinting of synaptic connectivity and neural circuitry in the infant brain. In this application of nonlinear concepts to developmental models of both resistance against and vulnerability to mental disorders, particular emphasis is placed upon the experience-dependent maturation of a system in the orbital prefrontal cortex that regulates psychobiological state and organismic energy balance. This frontolimbic system is expanded in the nonlinear right hemisphere that generates stress-regulating coping strategies, and it serves as the hierarchical apex of the limbic and autonomic nervous systems. Early forming microstructural alterations and energetic limitations of this regulatory system are suggested to be associated with a predisposition to psychiatric disorders.

Biogenic Monoamines↗
PubMed1983

Multisystem-Multimethod family assessment in clinical contexts.

A framework for assessing multiple levels of the family system by using multiple methodologies is proposed in this paper. This approach for measuring family phenomena is referred to as Multisystem-Multimethod (MS-MM) family assessment. Ideas from systems theory, measurement theory, and clinical application are used to describe the measurement strategy. A clinical case example is offered illustrating one way in which a MS-MM procedure can be implemented with families. Several currently available assessment tools are utilized to assess the individual, marital, and family levels of the family system. This diversity of measurement techniques provides convergent and divergent information within and across system levels. An MS-MM procedure has the capacity to assess the wholistic qualities of systems as well as specific issues within the boundaries of particular family subsystems.

Adolescent↗
PubMed1977

[The anosognostic psychosyndrome. Studies and reflections on a case of acoustic agnosia].

We analyse structure and dynamics of anosognostic behavior by means of a case with auditory agnosia for both linguistic and non-linguistic material. First we investigate on the observational level the structural interweaving of conditions. Second we make an attempt of a structural dynamic analysis with inclusion of both neurophysiological and psychodynamic aspects within a frame which is orientated towards system theories. By doing this, the anosognostic syndrome which is describable in a phenomenalistic sense as a disturbance of body-scheme, neuropsychologically as a neglect-or extinction-syndrome and psychodynamically as regressive Ego dissolution, appears as disintegration of the transactional coherence between specific and non-specific functional systems. At the time also the relations to the structure of focal brain syndromes and organic psychoses are dealt with.

Agnosia↗
PubMed1994

Functional properties of the brain during sleep under subchronic zopiclone administration in man.

Zopiclone, a non-benzodiazepine, has been shown to be efficient in the treatment of transient, short-term or chronic sleep disorders. Apart from its hypnotic effects zopiclone has anxiolytic, anticonvulsant and myorelaxant properties and is therefore hardly distinguishable from benzodiazepines. Dependence liability and discontinuation effects have been reported to be less pronounced. Therefore zopiclone seems to be a hypnotic drug which may cause fewer side effects than conventional benzodiazepines. From the electrophysiological point of view one requires from a hypnotic drug the induction of a physiological sleep pattern as well as no alterations of information processing by the brain. The aim of the present study was to investigate the subchronic effect of zopiclone medication on some functional properties of the sleep EEG in healthy subjects. In order to get better insight into the principles of information processing by the brain during sleep and its alterations under the influence of zopiclone we applied some tools from linear system theory to sleep EEG data. For this purpose we investigated late components of auditory and visual evoked potentials during different sleep stages and calculated from these the so-called amplitude-frequency characteristic of the brain. This function describes the relationship between an input and the output of the investigated system. The main advantage of this kind of analysis is that it enables one to detect functional differences during sleep stages. This information can hardly be obtained from conventional spectral analysis. As a result we could demonstrate that under subchronic zopiclone medication no quantitative or qualitative alterations of the functional sleep EEG properties concerning the transfer properties of the brain under auditory and visual stimulation were detectable.

Adult↗
PubMed2003

Evolutionary psychology from a developmental systems perspective: comment on Lickliter and Honeycutt (2003).

Although agreeing with R. Lickliter and H. Honeycutt (2003) that evolutionary psychology lacks and should adopt a coherent developmental model to explain how evolved mechanisms become expressed in phenotypes, it is argued that adhering to the principles of developmental systems theory, despite enhancing evolutionary psychology, would not change appreciably its basic focus. The concepts of innateness and modularity, what is inherited and what evolves, as well as the possible role of developmental plasticity in the evolution of human cognition are discussed. It is proposed that evolutionary psychology can incorporate the developmental systems perspective into its theorizing, with the end result being a science that more closely reflects human nature.

Biological Evolution↗
PubMed1977

The dynamics of density dependent population models.

The dynamics of density-dependent population models can be extraordinarily complex as numerous authors have displayed in numerical simulations. Here we commence a theoretical analysis of the mathematical mechanisms underlying this complexity from the viewpoint of modern dynamical systems theory. After discussing the chaotic behavior of one-dimensional difference equations we proceed to illustrate the general theory on a density-dependent Leslie model with two age classes. The pattern of bofurcations away from the equilibrium point is investigated and the existence of a "strange attractor" is demonstrated--i.e. an attracting limit set which is neither an equilibrium nor a limit cycle. Near the strange attractor the system exhibits essentially random behavior. An approach to the statical analysis of the dynamics in the chaotic regime is suggested. We then generalize our conclusions to higher dimensions and continuous models (e.g. the nonlinear von Foerster equation).

Ecology↗
PubMed1996

Integrated local health systems in Central America.

This paper describes a few Central American experiences related to the development of integrated, participatory health care systems. Theory and analytic method center on the tensions inherent in the dichotomies of professional/popular, center/periphery and biomedical/traditional. Using a framework rooted in the World Health Organization's 1978 call for 'health for all' based on community-oriented primary care, this paper concludes that the underlying conditions necessary for truly integrated local health systems have not yet developed. Except for the cases of Costa Rica during 1978-1982 and Nicaragua during 1979-1990, the political will to create and support such systems has not existed. Perhaps more importantly, the cultural milieu in which Central Americans interact with their society fosters an individualistic, commercial, and paternalistic citizen/society relationship rather than the cooperative, community-oriented and democratic spirit needed for successful development of integrated local health systems. Nevertheless, there are a number of positive examples from which we can learn, and a growing tradition of citizen participation which may lead toward appropriate, sustainable, and truly integrated local health systems.

Central America↗
PubMed1993

Relationships between depression and attachment styles in parent- and institution-reared Turkish children.

The present study, using a sample of Turkish children, aimed to test two attachment-theory predictions: (a) institution-reared children who were separated from their parents at an early age are less likely to have secure attachment schemata than children from two-parent families, and (b) depressive schemata are positively related to insecure attachment schemata and negatively related to secure attachment schemata. Following a systems-theory perspective, we also predicted that the relationship between depression and attachment styles would be stronger for institution-reared children than for children from two-parent families. Hazan and Shaver's (1987) attachment-style items and the Beck Depression Inventory were administered to 20 institution-reared and 20 parent-reared boys by a female interviewer. The results supported the first two predictions of the study.

Child↗
PubMed1981

Psychologic support for children with soft tissue and bone sarcomas.

Advances in pediatric hematology and oncology during the last decade have increased the survival rate of children with cancer. If treatment is to be successful, optimally, psychologic and physical issues, though they may become indistinguishable from one another, must be taken into consideration. Using the system theory concept, I examined the impact of the various professionals on the sick child. To facilitate better care, the liaison Pediatric Psychiatry Service at Beth Israel Medical Center in New York City developed a series of psychiatric interventions that deal with the psychologic needs of the various components of the medical-therapeutic system. These include preparation of a psychosocial profile of the sick child and his family; group meetings for nurses, house staff, and attending physicians in hematology and oncology; and discussions with the parents. The patient is perceived as a biopsychologic system, the natural unit in which it is possible to discern and abstract the psychologic subsystem and the biologic subsystem. Psychiatric intervention with the psychologic subsystem is intended to facilitate the cure and recovery of the biologic subsystem.

Adolescent↗
PubMed1981

The spectro-temporal receptive field. A functional characteristic of auditory neurons.

The Spectro-Temporal Receptive Field (STRF) of an auditory neuron has been introduced experimentally on the base of the average spectro-temporal structure of the acoustic stimuli which precede the occurrence of action potentials (Aertsen et al., 1980, 1981). In the present paper the STRF is considered in the general framework of nonlinear system theory, especially in the form of the Volterra integral representation. The STRF is proposed to be formally identified with a linear functional of the second order Volterra kernel. The experimental determination of the STRF leads to a formulation in terms of the Wiener expansion where the kernels can be identified by evaluation of the system's input-output correlations. For a Gaussian stimulus ensemble and a nonlinear system with no even order contributions of order higher than two, it is shown that the second order cross correlation of stimulus and response, normalized with respect to the spectral contents of the stimulus ensemble, leads to the stimulus-invariant spectro-temporal receptive field. The investigation of stimulus-invariance of the STRF for more general nonlinear systems and for stimulus ensembles which can be generated by nonlinear transformations of Gaussian noise involve the evaluation of higher order stimulus-response correlation functions.

Acoustic Stimulation↗