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At least 541 records · Page 30Linked to original sources
PubMed2000

A mathematical model of tumour angiogenesis incorporating cellular traction and viscoelastic effects.

Angiogenesis is defined as the outgrowth and formation of new vessels from a pre-existing vascular network (Rakusan, In: Cardiac Growth and Regeneration. Annals of the New York Academy of Sciences, 1995), and is of fundamental importance in understanding the processes by which a tumour achieves vascularization. Diffusible substances, collectively called tumour angiogenesis factors are released from the tumour to elicit a variety of responses from the surrounding tissues, most importantly the migration of endothelial cells (lining neighbouring vessels) towards the tumour. To facilitate locomotion, the cells exert appreciable traction forces upon the interstitial extracellular matrix which, in turn, influences the resulting direction of their migration. In this paper, we examine the role played by cellular traction during cell migration and the corresponding viscoelastic effects of the extracellular matrix.

Cell Movement↗
PubMed1996

Self-similar Neural Networks Based on a Kohonen Learning Rule.

One of the most striking features about the perceptual machinery of mammals is its regularity of structure. This is particularly evident in the mammalian visual system, as the work pioneered by Hubel and Wiesel has demonstrated. The likely source of this regularity is the visual stimulus, which does not change randomly from instant to instant, but is affected primarily by motions of both the animal and objects in the environment. These motions induce structured changes in the visual stimulus, which might well be expected to have a significant effect in shaping the structure of the visual machinery, whether through individual plasticity or longer-term genetic changes.The work reported in this paper is an investigation of the structures that may evolve in a simple artificial neural network driven not by random changes of input pattern, but directly by transformations which are themselves related to transformations of the input signal through an analysis of motion-prediction error. Results are presented which demonstrate that such networks can evolve a remarkable degree of regularity which reflects the underlying symmetry group of the transformations, both in one and two dimensions. An appropriate and visually plausible choice of transformation group can lead to the development of foveal structures in two-dimensional networks. We also present some preliminary results on parametrised function spaces which support the general conclusion that global structure bearing a considerable resemblance to that found in the mammalian visual system can evolve as the result of a simple learning rule in networks driven by transformations similar to those typically encountered in vision. Copyright 1996 Elsevier Science Ltd

Journal Article↗
PubMed2002

Reconfigurable networking for coordinated multi-agent sensing and communications.

An implementation of a neurally-inspired system comprised of multiple mobile sensor-effector agents is described. Each agent has features of a complex neural network that is able to communicate and adjust its behavior depending upon a variety of parameters, including changes in the environment and the behavior of other agents. The system as a whole spatiotemporally reconfigures itself to perform coordinated behaviors not obtainable with single agents. Transient clustering of agents into functional subsystems to perform specific tasks generates a "system of systems" architecture. The interesting findings of this dynamic platform show that (a) the formation and dissolution of functional subsystems is a local phenomenon without the need for global control and (b) minimal intermittent communication among the agents can yield large-scale, coordinated, goal-driven behavior under a wide range of conditions.

Aerospace Medicine↗
PubMed1998

From reviving the living to raising the dead; the making of cardiac resuscitation.

Cardiac arrest (the process of the heart ceasing to beat) and cardiac resuscitation (the attempt to restart the heart) were created in the surgical theatres of the early to middle twentieth century, in response to the cardiac arrests which were being caused by the "theatre" doctors themselves. These patients were young and healthy (a consequence of the preselection surgery involves), cardiac resuscitation was trying to revive the living. The paper explores the intimate relationship between cardiac arrest and cardiac resuscitation. By the use of historical and Latourian sociological analysis the paper also reveals how cardiac resuscitation was made into the emblematic medical event it is today, a process which has been so complete that it has become, in many senses, an "obligatory passage point to death", that is, in order to die one must pass through cardiac resuscitation. The outcome of this is the changed nature of cardiac resuscitation, no longer attempting to revive the living, cardiac resuscitation now attempts to raise the dead and dying, and at this it fails. Despite the remarkable success of cardiac resuscitation as a fact, the paper argues that it is a failure as a technique, paradoxically the more successful a fact it became, the more it failed as a procedure. The paper explains this apparent contradiction and the resistance to anomalies, by showing how cardiac resuscitation was created simultaneously inside and outside medical science, from its very start being a social and scientific fact with a vast network of stabilising allies.

Attitude to Death↗
PubMedDate not supplied

Linking ecological science to decision-making: delivering environmental monitoring information as societal feedback.

The paper describes the Ecological Monitoring and Assessment Network's (EMAN) operational and program response to certain challenges of environmental monitoring in Canada, in particular, efforts to improve the ability of the network to deliver relevant information to decision makers. In addition to its familiar roles, environmental monitoring should deliver feedback to society on environmental changes associated with development patterns, trends, processes and interventions. In order for such feedback to be effective, it must be relevant, timely, useful and accessible: all characteristics that are defined by the user, not the provider. Demand driven environmental monitoring is explored through EMAN's experiences with Canada's Biosphere Reserves, the NatureWatch Program and the Canadian Community Monitoring Network.

Canada↗
PubMed2003

Social networks, travel and talk.

This paper considers the role that physical, corporeal travel plays in social life. There is a large and increasing scale of such travel. This increase has occurred simultaneously with the proliferation of communication devices that in some ways substitute for physical travel. I hypothesize that the bases of such travel are new ways in which social life is 'networked'. Such increasingly extensive networks, hugely extended through the informational revolution, depend for their functioning upon intermittent occasioned meetings. These moments of physical co-presence and face-to-face conversation, are crucial to patterns of social life that occur 'at-a-distance', whether for business, leisure, family life, politics, pleasure or friendship. So life is networked but it also involves specific co-present encounters within specific times and places. 'Meetingness', and thus different forms and modes of travel, are central to much social life, a life involving strange combinations of increasing distance and intermittent co-presence. The paper seeks to examine the place of travel within the emergent pattern of a 'networked sociality'. It seeks to contribute to the emerging 'mobility turn' within the social sciences.

Automobile Driving↗
PubMed2004

From innovation to social norm: bounded normative influence.

CORRECTION: Every innovation begins as a deviation from existing social norms. Given the strong effect of social norms and pressure, how can any innovation ever diffuse to the point where it becomes a new social norm? The seeming paradox of how a minority can influence the majority has not been explained well by prevailing social science theory. Computer simulations of the diffusion of a new behavior within the social network of a Bangladesh village led to the discovery of a new principle of social change that resolves this paradox. The results revealed the important but overlooked role played by boundaries that emerge within a social network and how such local boundaries affect the creation of a new social norm. A minority position can become the social norm by means of the process of bounded normative influence. As long as a minority maintains its majority status within its own, locally bounded portion of the network, then it can survive, recruit converts in the near surround, and establish its behavior as the norm for the network as a whole. The process is accelerated when the minority subgroup is centrally located in the network and communicates more frequently and persuasively than the majority.

Bangladesh↗
PubMed2003

The Region 4 collaborative virtual reference project.

In May 2002, the Denison Memorial Library at the University of Colorado Health Sciences Center and the J. Otto Lottes Health Sciences Library at the University of Missouri-Columbia, with funding from the National Network of Libraries of Medicine-Midcontinental Region, embarked on a collaborative, real-time reference project using the 24/7 Reference, Inc., software package. This paper describes how the project was conceived, and includes details on the service hours, staffing, training, marketing, lessons learned, and future plans for the service.

Colorado↗
PubMedDate not supplied

Managing for technology to improve service.

What challenges today's healthcare executive is deciding what new technologies to purchase and exactly when to do so. Scan the marketplace for them--both in the healthcare field and in industry.

Computer Communication Networks↗
PubMed1997

The microprocessor and medicine.

Technology continues to accelerate at an amazing pace. Where have we been, where are we going, and what do these technology enhancements mean to the health care industry? We are entering the era of the personal computer becoming the window to the multimedia digital world of cyberspace. Microprocessors will continue to improve from one generation to the next to make cyberspace as realistic as possible-and with their improving capabilities will come myriad applications for health care services, either not cost-effective, or not even contemplated, until now. As a leader of an organization, one who approves substantial budgets for information technology, you must ask yourself what new products and services these startling technological advances will create. How will they change health and medical care?

Computer Communication Networks↗
PubMed2000

Louisiana Rural Health Access Program.

Louisiana Rural Health Access is part of a Robert Wood Johnson Foundation project to address primary and preventive medical care for indigent, uninsured people residing in underserved rural parishes. This 15-month grant funds the development of a pilot program to improve access to health care in Acadia, Evangeline, Iberia, Lafayette, St Landry, St Martin, St Mary, and Vermilion parishes. Led by representatives from the Department of Health and Hospitals and the Louisiana State University Health Sciences Center, team committees designed the program's innovative use of telemedicine, loan development, network integration, and community involvement. A benefit of the program will be to measure the outcomes of each objective in order to determine which intervention works best. This information will be invaluable for the design of a five-year rural health care development plan.

Capital Financing↗
PubMed2001

Predictors of self-care behavior in adults with type 2 diabetes: an RRNeST study.

BACKGROUND AND OBJECTIVES: Fourfactors have been linked with self-care behaviors in patients with type 2 diabetes: (1) patient demographics, (2) doctor-patient relationship, (3) stress, and (4) social context. This study determined the relationship of each of these factors on self-care behavior in diabetic family practice patients. METHODS: We conducted a cross-sectional survey of patients seeking care in the outpatient clinics of the Residency Research Network of South Texas (RRNeST), a network of six family practice residency programs affiliated with the University of Texas Health Science Center at San Antonio. A total of 397 consecutive adults with type 2 diabetes presenting for appointments with family medicine faculty and family practice residents over a 6-month time period were surveyed about various factors and their relationship to self-care behavior pertinent to diabetes. RESULTS: Self-care was related to age, patient satisfaction with his/her doctor-patient relationship, personal stress, and family context. Social context, as reflected by the statement "My family understands my diabetes," was strongly associated with diet, exercise, and medication adherence. Multivariate analysis demonstrated that, after controlling for patient demographic characteristics andpatient satisfaction, personal stress and social context were strongly associated with self-care, especially diet. CONCLUSIONS: Social context, specifically the family, is significantly associated with self-care behaviors. Attempts to improve self-care behavior should include thefamily members of the diabetic patient. Since family physicians often provide care to multiple members of the family, they are ideally positioned to implement these interventions.

Age Factors↗