bluuebunny/crossref_metadata_2025 huggingface dataset:
Combining constitutive materials modeling with atomic force microscopy to understand the mechanical properties of living cells
Authors: McElfresh Mike , Baesu Eveline , Balhorn Rod , Belak James , Allen Michael J. , Rudd Robert E.
Published: December 2002

The goal of this work is to study the properties of living cells and cell membranes by using atomic force microscopy. During atomic force microscopy (AFM) measurement, there is a strong mechanical coupling between the AFM tip and the cell. The purpose of this paper is to present a model of the overall mechanical response of the cell that allows us to separate out the mechanical response of the cell from the local surface interactions we wish to quantify. These local interactions include recognition (or binding) events between molecules bound to an AFM tip (e.g., an antibody) and molecules or receptors on the cell surface (e.g., the respective antigen). The computational model differs from traditional Hertzian contact models by explicitly taking into account the mechanics of the biomembrane and cytoskeleton. The model also accounts for the mechanical response of the living cell during arbitrary deformation. The indentation of a bovine sperm cell is used to test the validity of this model, and further experiments are proposed to fully parameterize the model.
Distributed response analysis of conductive behavior in single molecules
Authors: in het Panhuis Marc , Munn Robert W. , Popelier Paul L. A. , Coleman Jonathan N. , Foley Brian , Blau Werner J.
Published: December 2002

Theab initiocomputational approach of distributed response analysis is used to quantify how electrons move across conjugated molecules in an electric field, in analogy to conduction. The method promises to be valuable for characterizing the conductive behavior of single molecules in electronic devices.
Quantum dot artificial solids: Understanding the static and dynamic role of size and packing disorder
Authors: Beverly K. C. , Sample J. L. , Sampaio J. F. , Remacle F. , Heath J. R. , Levine R. D.
Published: December 2002

This perspective examines quantum dot (QD) superlattices as model systems for achieving a general understanding of the electronic structure of solids and devices built from nanoscale components. QD arrays are artificial two-dimensional solids, with novel optical and electric properties, which can be experimentally tuned. The control of the properties is primarily by means of the selection of the composition and size of the individual QDs and secondly, through their packing. The freedom of the architectural design is constrained by nature insisting on diversity. Even the best synthesis and separation methods do not yield dots of exactly the same size nor is the packing in the self-assembled array perfectly regular. A series of experiments, using both spectroscopic and electrical probes, has characterized the effects of disorder for arrays of metallic dots. We review these results and the corresponding theory. In particular, we discuss temperature-dependent transport experiments as the next step in the characterization of these arrays.
Estrogenicity of domestic and industrial effluents in Sweden
Authors: Svenson Anders , Örn Stefan , Allard Ann-Sofie , Viktor Tomas , Parkkonen Jari , Olsson Per-Erik , Förlin Lars , Norrgren Leif
Published: December 2002

Estrogenicity in Swedish wastewaters was surveyed. Estrogenicity was examined using a recombinant yeast cell test and analyses of the yolk protein precursor in the blood of caged juvenile rainbow trout at sites close to wastewater outlets or in continuous flow tanks of undiluted wastewater. Estrogenic effects corresponding to <0.1 to 15 ng estradiol equivalents were found in municipal effluents. In 9 of 12 industrial effluents, estrogenic effects were below the detection limit of the screen test. None of the six effluents from the pulp and paper industry, from a steel works, and from two chemical industries had a detectable estrogenic effect. Two assays were used for analysis of plasma vitellogenin, a heterologous enzyme-linked immunosorbent assay and a homologous radio immunoassay. Exposure to undiluted municipal wastewater resulted in increased levels of vitellogenin in the plasma of juvenile trout. Using the more sensitive RIA test, increased levels of plasma vitellogenin were detected in cage exposure of rainbow trout in municipal effluent receiving waters. Textile industry effluents mixed with domestic wastewater were estrogenic probably due to contributions from the domestic effluent. In some effluents, toxicity may have masked estrogenic effects.
Incorporating a Psychological Counselor in a Cancer Risk Assessment Program: Necessity, Acceptability, and Potential Roles
Authors: Matthews Alicia K. , Brandenburg Dana L. , Cummings Shelly , Olopade Olufunmilayo I.
Published: December 2002

Evidence suggests that cancer risk assessment may be associated with increased psychological distress. This exploratory study assessed the necessity and acceptability of incorporating psychological counseling into routine clinic procedures at a cancer risk program. Following a visit to a university‐based cancer risk clinic, patients (N = 102) completed an anonymous self‐report instrument. Participants reported experiencing current stress and anxiety (41%), depression (29%), and suicidal ideation (2%). Patients with a history of cancer were more likely to be experiencing current emotional difficulties. Sixty‐nine percent of the participants found the visit with the psychological counselor to be helpful, while 41% of the participants reported interest in follow‐up psychological services. Interest in receiving future psychological services was positively correlated with levels of anxiety, depression, and cancer worry. This pilot study demonstrates the acceptability and potential role for psychological counselors in increasing adjustment in high‐risk patients undergoing genetic counseling for inherited cancers.
The Inner World of the Genetic Counselor
Authors: Abrams Liane J. , Kessler Seymour
Published: December 2002

The external experience of genetic counselors reflects and is processed in their personal inner worlds. A small window into that private interior is opened here revealing the strengths and frailties, vulnerabilities and sensitivities professionals bring to bear in their work. The relational, human interplay—between counselor and colleagues, counselor and clients, counselors in their nonprofessional roles relative to others—is the primary focus of the interior experience.
Determining Complex Genetic Risks by Computer
Authors: Flodman Pamela , Hodge Susan E.
Published: December 2002

Genetic risk analysis is a frequent and important responsibility for genetic counselors. Computer‐based methods of determining risk are available but not generally used. In this paper, we present a computer‐based likelihood approach for performing risk calculations (including Bayesian analysis), and the implementation of this approach using the CYRILLIC and LINKAGE computer packages. Several concrete examples are given, and caveats (which can also be applied to other programs for risk calculation) are discussed.
Models of Genetic Counseling and Their Effects on Multicultural Genetic Counseling
Authors: Lewis Linwood J.
Published: December 2002

This theoretical paper examines challenges to multicultural genetic counseling, counseling between culturally different clients and counselors, in the context of Kessler's typology of models of genetic counseling (Kessler S (1997) J Genet Counsel 6:287–295). It is suggested that challenges such as resistance to multicultural genetic counseling education may be due to conceptions about genetic counseling as a biomedical field that transcends questions of culture as well as lack of multicultural training or prejudice. Directions for future research and recommendations for multicultural genetic counseling education are briefly explored.
Komrower Lecture: New names for old disciplines
Authors: Galjaard H.
Published: December 2002

Since the completion of the human genome map, genomics, proteomics and pharmacogenomics have become popular headings. In this review some 40 years of development in research and laboratory diagnosis of inborn errors of metabolism are summarized. It is shown that collaborative approaches of clinicians, geneticists, pathologists, biochemists and molecular biologists have contributed significantly to the (prenatal) diagnosis, genetic counselling and prevention of simple gene disorders, and in some instances to successful treatment. DNA technology widens the range to predictive risk testing for multifactorial disorders manifesting in adulthood. This offers new perspectives for potential patients and their close relatives, but also poses new psychosocial and ethical problems.

Despite high expectations of new technologies in the development of new medicines for multifactorial disorders, examples of previous studies on the molecular etiology and pathogenesis of monogenic diseases indicate that a long way is ahead of us. Also the treatment of rare disorders and equal access to cure and care in the Third World need great attention.
The Human Genome Project and the future of diagnostics, treatment and prevention
Authors: van Ommen G.‐J. B.
Published: December 2002

The Human Genome Project, the mapping of our 30 00–50 000 genes and the sequencing of all of our DNA, will have major impact on biomedical research and the whole of therapeutic and preventive health care. The tracing of genetic diseases to their molecular causes is rapidly expanding diagnostic and preventive options. The increased insights into molecular pathways, gained from high‐throughput ‘functional genomics’, using DNA‐chip and protein‐chip approaches and specially designed animal model systems, will open great prospects for pharmacological and genetic therapies. Powerful bioinformatics and biostatistics will further improve our pattern recognition and accelerate progress. A rapidly expanding area of high expectations is that of ‘pharmacogenomics’: the design of more effective drugs with lower toxicity through tailoring of drug treatment to individual, genetically determined differences in drug metabolism. Not only will this decrease the cost of health care through reduction of adverse drug reactions, but a better stratification of populations will also provide more statistical power farther upstream in drug trials. However, the optimal benefits from the current explosion of ‘data mining’ will only be realized when the basic data are made and kept publicly accessible, while at the same time safeguarding the protection of intellectual property arising from downstream inventions. This is one of the goals of HUGO, the international Human Genome Organization, established 13 years ago to assist coordination of data acquisition and exchange and societal implementation of the genome project. Additional points of attention in this historic endeavour are the prevention of stigmatization and discrimination and the safeguarding of a worldwide balance in the contribution by — and benefits to — different populations, while respecting the diversity in cultures and traditions.
Open Systems and Consciousness: A Philosophical Discussion
Authors: Ingarden Roman S.
Published: December 2002

The proposition of the author is that sentences about sentences (meta-sentences or sentences of the 2nd order) about physical phenomena are examples of conscious thinking, i.e. the elements of consciousness. The argument is that psychical phenomena (acts of thinking or imagination) are phenomena of the second logical type: phenomena of phenomena. In other words, the individual psychical world (the world of individual consciousness) is described by a meta-theory of physics (meta-physics), while the social world (the world of social culture) can be described by a meta-meta-physics, i.e., by doubled-type description by means of sentences two logical types higher than those of the physical world. The objects in the physical world (particles, bodies, animals, persons, etc.) are defined as open systems, relatively isolated in a hypothetical physical closed universe, i.e., open systems having internal and external energy of interaction. The role of subconscious activity of the brain is also considered and explained, as well as the importance of genes and hormones for an emotional proto-language in animals and humans, and of the human language as a social software being the base for proper human consciousness. The aspect of open systems is here only slightly touched. It will be discussed in more details elsewhere.
The Evolution of Epistemology and Concepts in an Iterative‐Generative Reflective Practice: The Importance of Small Differences
Authors: Bishop Brian J. , Sonn Christopher C. , Drew Neil M. , Contos Natalie E.
Published: December 2002

Using a contextualist epistemology, it would be expected that regional differences in community psychology would develop over time. It is argued that the epistemology and theory of Western Australian community psychology, while largely based on North American approaches, has developed its own idiosyncracies. These developed through the integration of practice and theory in an “iterative‐generative” fashion. The process of development is conceptualized in terms of Schön's and Altman's distinctions between foundational knowledge, and professional and socially responsive knowledge (I. Altman, 1996; D. A. Schön, 1983). It has also been characterized as an incremental development based on the reflection on tacit and conceptual knowledge. From the small differences that have developed between regions, a dialogue can emerge that will better allow understanding of how social forces shape people's actions.
Yeast as a Model to Study Apoptosis?
Authors: Fleury Christophe , Pampin Mathieu , Tarze Agathe , Mignotte Bernard
Published: December 2002

Programmed cell death (PCD) serves as a major mechanism for the precise regulation of cell numbers, and as a defense mechanism to remove unwanted and potentially dangerous cells. Despite the striking heterogeneity of cell death induction pathways, the execution of the death program is often associated with characteristic morphological and biochemical changes termed apoptosis. Although for a long time the absence of mitochondrial changes was considered as a hallmark of apoptosis, mitochondria appear today as the central executioner of programmed cell death. This crucial position of mitochondria in programmed cell death control is not due to a simple loss of function (deficit in energy supplying), but rather to an active process in the regulation of effector mechanisms.

The large diversity of regulators of apoptosis in mammals and their numerous interactions complicate the analysis of their individual functions. Yeast, eukaryotic but unicellular organism, lack the main regulators of apoptosis (caspases, Bcl-2 family members, …) found in mammals. This absence render them a powerful tool for heterologous expression, functional studies, and even cloning of new regulators of apoptosis.

Great advances have thus been made in our understanding of the molecular mechanisms of Bcl-2 family members interactions with themselves and other cellular proteins, specially thanks to the two hybrid system and the easy manipulation of yeast (molecular biology and genetics).

This review will focus on the use of yeast as a tool to identify new regulators and study function of mammalian apoptosis regulators.
Bcl-2 Family of Proteins: Life-or-Death Switch in Mitochondria
Authors: Tsujimoto Yoshihide
Published: December 2002

An increase in the permeability of outer mitochondrial membrane is central to apoptotic cell death, and results in the release of several apoptogenic factors such as cytochrome c into the cytoplasm to activate downstream destructive programs. The voltage-dependent anion channel (VDAC or mitochondrial porin) plays an essential role in disrupting the mitochondrial membrane barrier and is regulated directly by members of the Bcl-2 family proteins. Anti-apoptotic Bcl-2 family members interact with and close the VDAC, whereas some, but not all, proapoptotic members interact with VDAC to open protein-conducting pore through which apoptogenic factors pass. Although the VDAC is involved directly in breaking the mitochondrial membrane barrier and is a known component of the permeability transition pore complex, VDAC-dependent increase in outer membrane permeability can be independent of the permeability transition event such as mitochondrial swelling followed by rupture of the outer mitochondrial membrane. VDAC interacts not only with Bcl-2 family members but also with proteins such as gelsolin, an actin regulatory protein, and appears to be a convergence point for a variety of cell survival and cell death signals.
Traumatic events and physical health in a New Zealand community sample
Authors: Flett Ross A. , Kazantzis Nikolaos , Long Nigel R. , MacDonald Carol , Millar Michelle
Published: December 2002

Traumatic event exposure and physical health were examined in a community‐residing sample of 1,500 New Zealand adults. Half (51%) reported past traumatic event exposure, 9% reported recent (past 12 months) trauma exposure, and 40% reported no exposure. After adjusting for gender, ethnic, and age differences, those experiencing crime and accident trauma exhibited significantly deteriorated physical health, as measured by current physical symptoms, chronic medical conditions, and chronic limitations in daily functioning. Further research is required to assess the influence of traumatic events on the physical health among adults from other countries, and to evaluate the factors that may mediate or moderate this relationship for different subgroups of the New Zealand population. Limitations of this study are outlined.
A preliminary investigation of alcohol use during trauma and peritraumatic reactions in female sexual assault victims
Authors: Clum Gretchen A. , Nishith Pallavi , Calhoun Karen S.
Published: December 2002

The purpose of these analyses was to investigate the association between reported alcohol use during a sexual assault and perceptions of assault severity and physical and emotional peritraumatic reactions. Self‐report data were collected on 57 sexually assaulted college women. Multivariate regression analyses revealed that perception of assault severity mediated the relationship between alcohol use and peritraumatic physical reactions.
Civilian‐based posttraumatic stress disorder and physical complaints: Evaluation of depression as a mediator
Authors: Miranda Robert , Meyerson Lori A. , Marx Brian P. , Tucker Phebe M.
Published: December 2002

This study examined the role of comorbid depression in the somatic complaints of 32 individuals with civilian‐based posttraumatic stress disorder (PTSD) while restricting the influence of detectable pathophysiology and additional psychiatric conditions. It was hypothesized that depressive symptomatology would mediate the relationship between PTSD and somatic symptom reporting. Participants were administered structured clinical interviews, a physical examination, and an electrocardiogram. Results of this study supported the hypothesis that depressive symptoms mediate the relationship between PTSD and physical complaints. These results add to a growing body of literature that suggests psychological factors play an influential role in the physical symptom reports of individuals with PTSD.
Defining Moments: Catalysts for Professional Development
Authors: Veach Patricia McCarthy , Bartels Dianne M. , LeRoy Bonnie S.
Published: December 2002

In this series of papers, 17 genetic counselors describe defining moments, that is, personal experiences or events that led to a further realization of themselves as genetic counselors. These experiences, both positive and negative, describe a significant impact on the authors' professional growth and development. A call for papers was issued through the National Society of Genetic Counselors listserv and through theJournal of Genetic Counselingin 2001. This call resulted in the following 15 papers in which the authors were asked to describe the nature of a defining moment and how it affected their professional identity and practice. The authors provided an account of the experience or event, what it was about the experience that made it a defining moment, how it affected them personally and professionally, and if a defining moment was negative, how they were able to derive positive outcomes. Implications of these defining moments for other genetic counselors are discussed in a concluding paper.
Sequence analysis of Hungarian LHON patients not carrying the common primary mutations
Authors: Horvath J. , Horvath R. , Karcagi V. , Komoly S. , Johns D. R.
Published: December 2002

We describe sequence analysis of the mitochondrial DNA of five Hungarian patients diagnosed with probable LHON, who do not carry any of the three primary point mutations. We report three novel mutations, one of which might have a pathogenic role.
Cardiac involvement in Wilson disease
Authors: Hlubocká Z. , Mareček Z. , Linhart A. , Kejřová E. , Pospíšilová L. , Martásek P. , Aschermann M.
Published: December 2002

Background: Wilson disease is an inherited autosomal recessive disorder of copper metabolism resulting in pathological accumulation of copper in the liver, brain and other tissues. One of the reported manifestations is cardiac involvement.

Methods: We studied 42 patients with Wilson disease (19 men and 23 women, mean age 34±10 y) and 42 age‐ and sex‐matched healthy volunteers. All subjects underwent complete echocardiographic examination; 24 h ECG Holter monitoring was performed in 23 Wilson disease patients.

Results: In comparison to healthy subjects, patients with Wilson disease had increased thickness of the interventricular septum (9.5±1.4 vs 8.6±1.1 mm, p<0.01) and left ventriclular (LV) posterior wall (9.1±1.3 vs 8.2±1.0 mm, p<0.01). While the two groups did not differ in LV mass index, relative LV wall thickness was significantly increased in Wilson disease patients compared to control subjects (0.39±0.06 vs 0.34±0.04 p<0.001). Concentric LV remodelling was present in 9 patients (21%) and LV hypertrophy in one patient. Systolic LV function showed a nonsignificant trend towards lower values in Wilson disease patients (EF 62±5% vs 64±5%, p=0.06). Diastolic filling and the frequency of valvular abnormalities were comparable in both groups. The established echocardiographic abnormalities did not correlate with the type of Wilson disease manifestation, the presence of the His1069Gln mutation, laboratory parameters or the duration and type of therapy. Twenty‐four‐hour ECG Holter monitoring detected ECG abnormalities in 10 patients (42%), the most frequent findings being runs of supraventricular tachycardias and frequent supraventricular ectopic beats.

Conclusions: Cardiac involvement in Wilson disease patients was mild, characterized by LV parietal thickening with an increased prevalence of concentric LV remodelling and a relatively high frequency of benign supraventricular tachycardias and extrasystolic beats.
Neurotransmitter metabolites in CSF: An external quality control scheme
Authors: Bräutigam C. , Weykamp C. , Hoffmann G. F. , Wevers R. A.
Published: December 2002

We report an international external quality control scheme on neurotransmitter metabolites in cerebrospinal fluid (CSF). The neurotransmitter metabolites homovanillic acid (HVA), 5‐hydroxyindoleacetic acid (5‐HIAA) and 3‐methoxy‐4‐hydroxyphenylglycol (MHPG) are analysed to diagnose inborn errors of neurotransmitter metabolism. HVA is the catabolite of dopamine; 5‐HIAA is the catabolite of serotonin; and MHPG is the catabolite of noradrenaline. In the first phase, 12 laboratories from six countries participated in this special quality control scheme to define the present state of the art and achieve harmonization in analytical outcome and interpretation. In the second part, recoveries, dilutions and methods for sample preparation were compared. The results of 3 of 12 laboratories were excluded because of unacceptable intralaboratory coefficients of variations (CV) for HVA and/or 5‐HIAA. The inter‐ and intralaboratory CVs, the linearity and the recovery were acceptable for the other laboratories for both parameters.Unacceptable differences in the reference ranges between laboratories, leading to differences in interpretation of the results, became obvious. There was a significant improvement of the interlaboratory CV for HVA after standardization with a calibrator. The reproducibility of MHPG measurement appeared to be adequately established in only two laboratories and recovery was low in all five measuring this metabolite. The quality control scheme is an invaluable tool for controlling the analytical outcome and providing support to laboratories to improve their quality.
Pregnancy and tyrosinaemia type II
Authors: Cerone R. , Fantasia A. R , Castellano E. , Moresco L. , Schiaffino M. C. , Gatti R.
Published: December 2002

A female patient with tyrosinaemia type II is reported having undergone two untreated pregnancies. During pregnancies, plasma tyrosine was raised. The outcomes of both offspring show that maternal tyrosinaemia may have an adverse effect on the developing fetus.
Intestinal function in glycogen storage disease type I
Authors: Visser G. , Rake J. P. , Kokke F. T. M. , Nikkels P. G. J. , Sauer P. J. J. , Smit G. P. A.
Published: December 2002

Glycogen storage disease type I (GSD I) (McKusick 232200) is caused by inherited defects of the glucose‐6‐phosphatase complex. Patients with GSD Ia as well as patients with GSD Ib may suffer from intermittent diarrhoea, which seems to worsen with age. The cause of this diarrhoea is unknown. This study describes the results of investigations of intestinal functions and morphology in patients with GSD Ia and GSD Ib, which were performed to detect a common cause for chronic diarrhoea in GSD I. The following were investigated: faecal fat excretion, faecal α1‐antitrypsin and faecal chymotrypsin, expiratory H2 concentrations, persorption of cornstarch in urine and colonic biopsies. With the investigations presented in this study, no common cause for diarrhoea in GSD I was found. In GSD Ib loss of mucosal barrier function due to inflammation, documented by increased faecal α1‐antitrypsin excretion (3.5–9.6 mg/g dry faeces) and inflammation in the colonic biopsies, seems to be the main cause. The inflammation is most likely related to disturbed neutrophil function, which is often found in GSD Ib. Whether another cause is involved in GSD Ia and in GSD Ib, related to the disturbed function of glucose‐6‐phosphatase in the enterocyte, remains to be investigated.
A Qualitative Investigation of Somali Immigrant Perceptions of Disability: Implications for Genetic Counseling
Authors: Greeson Carrie J. , Veach Patricia McCarthy , LeRoy Bonnie S.
Published: December 2002

This study examined the potential utility of genetic counseling services for Somali immigrants by investigating their perceptions of disability. Five Somali women participated in structured interviews that assessed their perceptions of the nature, causes, and impact of disability, and care for persons with disabilities. Using a Heideggerian Hermeneutics qualitative method of analysis, six major themes emerged: (1) disability refers to both physical and mental conditions, with mental disability generally thought of first and as more severe; (2) in Somalia, the family cares for disabled family members, treating them as if they were “normal” (3) there are major cultural differences between Somalia and the United States in how persons with disabilities are treated; (4) caring for a person with a disability is stressful for the family; (5) Allah determines whether or not a child will be disabled, and this cannot be predicted or altered; and (6) family is the primary life focus, and therefore, risk of disability does not affect reproductive decisions. These themes suggest that traditional genetic counseling may have limited utility for Somali immigrants. We recommend several modifications to traditional genetic counseling for Somali patients that also may be useful for populations that have similar beliefs.
Allometric scaling of metabolic rate from molecules and mitochondria to cells and mammals
Authors: West Geoffrey B. , Woodruff William H. , Brown James H.
Published: December 2002

The fact that metabolic rate scales as the three-quarter power of body mass (
M
) in unicellular, as well as multicellular, organisms suggests that the same principles of biological design operate at multiple levels of organization. We use the framework of a general model of fractal-like distribution networks together with data on energy transformation in mammals to analyze and predict allometric scaling of aerobic metabolism over a remarkable 27 orders of magnitude in mass encompassing four levels of organization: individual organisms, single cells, intact mitochondria, and enzyme molecules. We show that, whereas rates of cellular metabolism
in vivo
scale as
M
−1/4
, rates for cells in culture converge to a single predicted value for all mammals regardless of size. Furthermore, a single three-quarter power allometric scaling law characterizes the basal metabolic rates of isolated mammalian cells, mitochondria, and molecules of the respiratory complex; this overlaps with and is indistinguishable from the scaling relationship for unicellular organisms. This observation suggests that aerobic energy transformation at all levels of biological organization is limited by the transport of materials through hierarchical fractal-like networks with the properties specified by the model. We show how the mass of the smallest mammal can be calculated (≈1 g), and the observed numbers and densities of mitochondria and respiratory complexes in mammalian cells can be understood. Extending theoretical and empirical analyses of scaling to suborganismal levels potentially has important implications for cellular structure and function as well as for the metabolic basis of aging.
Unified scaling law for earthquakes
Authors: Christensen Kim , Danon Leon , Scanlon Tim , Bak Per
Published: December 2002

We propose and verify a unified scaling law that provides a framework for viewing the probability of the occurrence of earthquakes in a given region and for a given cutoff magnitude. The law shows that earthquakes occur in hierarchical correlated clusters, which overlap with other spatially separated correlated clusters for large enough time periods and areas. For a small enough region and time-scale, only a single correlated group can be sampled. The law links together the Gutenberg–Richter Law, the Omori Law of aftershocks, and the fractal dimensions of the faults. The Omori Law is shown to be the short time limit of general hierarchical phenomenon containing the statistics of both “main shocks” and “aftershocks,” indicating that they are created by the same mechanism.
Self-organization in leaky threshold systems: The influence of near-mean field dynamics and its implications for earthquakes, neurobiology, and forecasting
Authors: Rundle J. B. , Tiampo K. F. , Klein W. , Sá Martins J. S.
Published: December 2002

Threshold systems are known to be some of the most important nonlinear self-organizing systems in nature, including networks of earthquake faults, neural networks, superconductors and semiconductors, and the World Wide Web, as well as political, social, and ecological systems. All of these systems have dynamics that are strongly correlated in space and time, and all typically display a multiplicity of spatial and temporal scales. Here we discuss the physics of self-organization in earthquake threshold systems at two distinct scales: (
i
) The “microscopic” laboratory scale, in which consideration of results from simulations leads to dynamical equations that can be used to derive the results obtained from sliding friction experiments, and (
ii
) the “macroscopic” earthquake fault-system scale, in which the physics of strongly correlated earthquake fault systems can be understood by using time-dependent state vectors defined in a Hilbert space of eigenstates, similar in many respects to the mathematics of quantum mechanics. In all of these systems, long-range interactions induce the existence of locally ergodic dynamics. The existence of dissipative effects leads to the appearance of a “leaky threshold” dynamics, equivalent to a new scaling field that controls the size of nucleation events relative to the size of background fluctuations. At the macroscopic earthquake fault-system scale, these ideas show considerable promise as a means of forecasting future earthquake activity.
Molecular dynamics analysis of a buckyball–antibody complex
Authors: Noon William H. , Kong Yifei , Ma Jianpeng
Published: December 2002

This is a multinanosecond molecular dynamics study of a bio–nano complex formed by a carbon nanoparticle, a buckyball C
60
, and a biological molecule, an antibody, with high binding affinity and specificity. In the simulation, the ball is completely desolvated by the binding site of the antibody by means of a nearly perfect shape complementarity and extensive side-chain interactions, with the exception that about 17% of the surface is persistently exposed to solvent and could be used for functional derivatization. The interactions are predominantly hydrophobic, but significant polar interactions occur as well. There exists a rich body of various π-stacking interactions. Aromatic side chains are involved in both double and triple stackings with the ball. Some ionic side chains, such as the guanidinium group of arginine, also form π-stackings with the ball. The results suggest that π-stackings are very efficient and common modes of biological recognition of π-electron-rich carbon nanoparticles. Most importantly, the results demonstrate that, in general, an ordinary protein binding site, such as that of an antibody, can readily bind to a carbon nanoparticle with high affinity and specificity through recognition modes that are common in protein–ligand recognition.
Predictability of catastrophic events: Material rupture, earthquakes, turbulence, financial crashes, and human birth
Authors: Sornette Didier
Published: December 2002

We propose that catastrophic events are “outliers” with statistically different properties than the rest of the population and result from mechanisms involving amplifying critical cascades. We describe a unifying approach for modeling and predicting these catastrophic events or “ruptures,” that is, sudden transitions from a quiescent state to a crisis. Such ruptures involve interactions between structures at many different scales. Applications and the potential for prediction are discussed in relation to the rupture of composite materials, great earthquakes, turbulence, and abrupt changes of weather regimes, financial crashes, and human parturition (birth). Future improvements will involve combining ideas and tools from statistical physics and artificial/computational intelligence, to identify and classify possible universal structures that occur at different scales, and to develop application-specific methodologies to use these structures for prediction of the “crises” known to arise in each application of interest. We live on a planet and in a society with intermittent dynamics rather than a state of equilibrium, and so there is a growing and urgent need to sensitize students and citizens to the importance and impacts of ruptures in their multiple forms.
Study of Nd
3+
, Pd
2+
, Pt
4+
, and Fe
3+
dopant effect on photoreactivity of TiO
2
nanoparticles
Authors: Shah S. I. , Li W. , Huang C.-P. , Jung O. , Ni C.
Published: December 2002

The metallorganic chemical vapor deposition method was successfully used to synthesize pure TiO
2
and Nd
3+
-, Pd
2+
-, Pt
4+
-, and Fe
3+
-doped TiO
2
nanoparticles. Polycrystalline TiO
2
structure was verified with x-ray diffraction, which showed typical characteristic anatase reflections without any separate dopant-related peaks. Transmission electron microscopy observations confirmed the existence of homogeneously distributed 22 ± 3 nm TiO
2
nanoparticles. The particle size remained the same for the doped samples. The doping level of transition metals was kept at ≈1 atomic percent, which was determined by x-ray photoelectron spectra and energy dispersive x-ray spectroscopy. The effects of different types of dopants on the photocatalytic activity were revealed by the degradation of 2-chlorophenols with an UV light source. The photocatalytic efficiency was remarkably enhanced by the introduction of Pd
2+
and Nd
3+
. Nd
3+
-doped TiO
2
showed the largest enhancement. However, Pt
4+
changed the 2-chlorophenol degradation rate only slightly, and Fe
3+
was detrimental to this process. These effects were related to the position of the dopants in the nanoparticles and the difference in their ionic radii with respect to that of Ti
4+
.
Agent-based modeling for understanding social intelligence
Authors: Conte Rosaria
Published: December 2002

The advantages of agent-based modeling for a general theory of intelligence at the individual and social level are emphasized over other existing approaches mainly relying on rationality theories. As was pointed out during the National Academy of Sciences Sackler Colloquium session “Implications of Agent-Based Modeling for Understanding Human Rationality and Learning,” held in October 2001, properties of social intelligent agents include adaptability and learning capacity, as well as the capacity to produce and employ artifacts and manipulate symbols.
Competition among cooperators: Altruism and reciprocity
Authors: Danielson Peter
Published: December 2002

Levine argues that neither self-interest nor altruism explains experimental results in bargaining and public goods games. Subjects' preferences appear also to be sensitive to their opponents' perceived altruism. Sethi and Somanathan provide a general account of reciprocal preferences that survive under evolutionary pressure. Although a wide variety of reciprocal strategies pass this evolutionary test, Sethi and Somanthan conjecture that fewer are likely to survive when reciprocal strategies compete with each other. This paper develops evolutionary agent-based models to test their conjecture in cases where reciprocal preferences can differ in a variety of games. We confirm that reciprocity is necessary but not sufficient for optimal cooperation. We explore the theme of competition among reciprocal cooperators and display three interesting emergent organizations: racing to the “moral high ground,” unstable cycles of preference change, and, when we implement reciprocal mechanisms, hierarchies resulting from exploiting fellow cooperators. If reciprocity is a basic mechanism facilitating cooperation, we can expect interaction that evolves around it to be complex, non-optimal, and resistant to change.
Agent-based modeling: Methods and techniques for simulating human systems
Authors: Bonabeau Eric
Published: December 2002

Agent-based modeling is a powerful simulation modeling technique that has seen a number of applications in the last few years, including applications to real-world business problems. After the basic principles of agent-based simulation are briefly introduced, its four areas of application are discussed by using real-world applications: flow simulation, organizational simulation, market simulation, and diffusion simulation. For each category, one or several business applications are described and analyzed.
Learning dynamics in social dilemmas
Authors: Macy Michael W. , Flache Andreas
Published: December 2002

The Nash equilibrium, the main solution concept in analytical game theory, cannot make precise predictions about the outcome of repeated mixed-motive games. Nor can it tell us much about the dynamics by which a population of players moves from one equilibrium to another. These limitations, along with concerns about the cognitive demands of forward-looking rationality, have motivated efforts to explore backward-looking alternatives to analytical game theory. Most of the effort has been invested in evolutionary models of population dynamics. We shift attention to a learning-theoretic alternative. Computational experiments with adaptive agents identify a fundamental solution concept for social dilemmas–−stochastic collusion–−based on a random walk from a self-limiting noncooperative equilibrium into a self-reinforcing cooperative equilibrium. However, we show that this solution is viable only within a narrow range of aspiration levels. Below the lower threshold, agents are pulled into a deficient equilibrium that is a stronger attractor than mutual cooperation. Above the upper threshold, agents are dissatisfied with mutual cooperation. Aspirations that adapt with experience (producing habituation to stimuli) do not gravitate into the window of viability; rather, they are the worst of both worlds. Habituation destabilizes cooperation and stabilizes defection. Results from the two-person problem suggest that applications to multiplex and embedded relationships will yield unexpected insights into the global dynamics of cooperation in social dilemmas.
Policy analysis from first principles
Authors: Moss Scott
Published: December 2002

The argument of this paper is predicated on the view that social science should start with observation and the specification of a problem to be solved. On that basis, the appropriate properties and conditions of application of relevant tools of analysis should be defined. Evidence is adduced from data for sales volumes and values of a disparate range of goods to show that frequency distributions are commonly fat-tailed. This result implies that any stable population distribution will generally have infinite variance and perhaps undefined mean. Models with agents that reason about their behavior and are influenced by, but do not imitate, other agents known to them will typically generate fat-tailed time series data. A simulation model of intermediated exchange is reported that is populated by such agents and yields the same type of fat-tailed time series and cross-sectional data that is found in data for fast moving consumer goods and for retail outlets. This result supports the proposition that adaptive agent models of markets with agents that reason and are socially embedded have the same statistical signatures as real markets. Whereas this statistical signature precludes any conventional hypothesis testing or forecasting, these models do offer unique opportunities for validation on the basis of domain expertise and qualitative data. Perhaps the most striking conclusion is that neither current social theory nor any similar construct will ever support an effective policy analysis. However, adaptive agent modeling is an effective substitute when embedded in a wider policy analysis procedure.
Tools and techniques for developing policies for complex and uncertain systems
Authors: Bankes Steven C.
Published: December 2002

Agent-based models (ABM) are examples of complex adaptive systems, which can be characterized as those systems for which no model less complex than the system itself can accurately predict in detail how the system will behave at future times. Consequently, the standard tools of policy analysis, based as they are on devising policies that perform well on some best estimate model of the system, cannot be reliably used for ABM. This paper argues that policy analysis by using ABM requires an alternative approach to decision theory. The general characteristics of such an approach are described, and examples are provided of its application to policy analysis.
Exploring cooperation and competition using agent-based modeling
Authors: Elliott Euel , Kiel L. Douglas
Published: December 2002

Agent-based modeling enhances our capacity to model competitive and cooperative behaviors at both the individual and group levels of analysis. Models presented in these proceedings produce consistent results regarding the relative fragility of cooperative regimes among agents operating under diverse rules. These studies also show how competition and cooperation may generate change at both the group and societal level. Agent-based simulation of competitive and cooperative behaviors may reveal the greatest payoff to social science research of all agent-based modeling efforts because of the need to better understand the dynamics of these behaviors in an increasingly interconnected world.
Emulating biology: Building nanostructures from the bottom up
Authors: Seeman Nadrian C. , Belcher Angela M.
Published: December 2002

The biological approach to nanotechnology has produced self-assembled objects, arrays and devices; likewise, it has achieved the recognition of inorganic systems and the control of their growth. Can these approaches now be integrated to produce useful systems?
A Qualitative Investigation of Student and Supervisor Perceptions of Live Supervision in Genetic Counseling
Authors: Hendrickson Susan M. , McCarthy Veach Patricia , LeRoy Bonnie S.
Published: December 2002

Live supervision of genetic counseling students is critical for ensuring quality client care and student clinical skill development. However, no research has investigated students' and supervisors' experience of this primary supervision method. In this study, separate focus groups of students and supervisors discussed their perceptions of the nature and impact of live supervision. A modified Consensual Qualitative Research method (Hill et al. (1997) Couns Psychol 25:517–572) was used to analyze the data. Results suggest that live supervision is an essential and effective method that promotes student skill development and professional development for both students and supervisors. There is a lack of formal training regarding supervision; most learning is trial and error. Students worry about being evaluated, and supervisors wonder if they are providing supervision effectively. Both samples emphasized that client care should not be compromised. Participant recommendations for improving live supervision are described, and suggestions are made for future research.
Fabry Disease in Genetic Counseling Practice: Recommendations of the National Society of Genetic Counselors
Authors: Bennett Robin L. , Hart Kimberly A. , O'Rourke Erin , Barranger John A. , Johnson Jack , MacDermot Kay D. , Pastores Gregory M. , Steiner Robert D. , Thadhani Ravi
Published: December 2002

The objective of this document is to provide health care professionals with recommendations for genetic counseling and testing of individuals with a suspected or confirmed diagnosis of Fabry disease, with a family history of Fabry disease, and those identified as female carriers of Fabry disease. These recommendations are the opinions of a multicenter working group of genetic counselors, medical geneticists, and other health professionals with expertise in Fabry disease counseling, as well as an individual with Fabry disease who is a founder of a Fabry disease patient advocacy group in the United States. The recommendations are U.S. Preventive Task Force Class III, and they are based on clinical experience, a review of pertinent English‐language articles, and reports of expert committees. This document reviews the genetics of Fabry disease, the indications for genetic testing and interpretation of results, psychosocial considerations, and references for professional and patient resources. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. The professional judgment of a healthcare provider, familiar with the facts and circumstances of a specific case, will always supersede these recommendations.