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PubMed1993

A discussion of the mind-brain problem.

In this paper Popper formulates and discusses a new aspect of the theory of mind. This theory is partly based on his earlier developed interactionistic theory. It takes as its point of departure the observation that mind and physical forces have several properties in common, at least the following six: both are (i) located, (ii) unextended, (iii) incorporeal, (iv) capable of acting on bodies, (v) dependent upon body, (vi) capable of being influenced by bodies. Other properties such as intensity and extension in time may be added. It is argued that a fuller understanding of the nature of forces is essential for the analysis of the mind-brain problem. The relative autonomy and indeterministic nature of mind is stressed. Indeterminism is treated in relation to a theorem of Hadamard. The computer theory of mind and the Turing test are criticized. Finally the evolution of mind is discussed.

Biophysical Phenomena↗

PubMed2004

Power optimization of wireless media systems with space-time block codes.

We present analytical and numerical solutions to the problem of power control in wireless media systems with multiple antennas. We formulate a set of optimization problems aimed at minimizing total power consumption of wireless media systems subject to a given level of QoS and an available bit rate. Our formulation takes into consideration the power consumption related to source coding, channel coding, and transmission of multiple-transmit antennas. In our study, we consider Gauss-Markov and video source models, Rayleigh fading channels along with the Bernoulli/Gilbert-Elliott loss models, and space-time block codes.

Algorithms↗

PubMedDate not supplied

Ligand-receptor pairing via tree comparison.

This paper introduces a novel class of tree comparison problems strongly motivated by an important and cost intensive step in drug discovery pipeline viz., mapping cell bound receptors to the ligands they bind to and vice versa. Tree comparison studies motivated by problems such as virus-host tree comparison, gene-species tree comparison and consensus tree problem have been reported. None of these studies are applicable in our context because in all these problems, there is a well-defined mapping of the nodes the trees are built on across the set of trees being compared. A new class of tree comparison problems arises in cases where finding the correspondence among the nodes of the trees being compared is itself the problem. The problem arises while trying to find the interclass correspondence between the members of a pair of coevolving classes, e.g., cell bound receptors and their ligands. Given the evolution of the two classes, the combinatorial problem is to find a mapping among the leaves of the two trees that optimizes a given cost function. In this work we formulate various combinatorial optimization problems motivated by the aforementioned biological problem for the first time. We present hardness results, give an efficient algorithm for a restriction of the problem and demonstrate its applicability.

Algorithms↗

PubMed2004

Prediction of elasticity constants in small biomaterial samples such as bone. A comparison between classical optimization techniques and identification with artificial neural networks.

Measuring the elasticity constants of biological materials often sets important constraints, such as the limited size or the irregular geometry of the samples. In this paper, the identification approach as applied to the specific problem of accurately retrieving the material properties of small bone samples from a measured displacement field is discussed. The identification procedure can be formulated as an optimization problem with the goal of minimizing the difference between computed and measured displacements by searching for an appropriate set of material parameters using dedicated algorithms. Alternatively, the backcalculation of the material properties from displacement maps can be implemented using artificial neural networks. In a practical situation, however, measurement errors strongly affect the identification results, calling for robust optimization approaches in order accurately to retrieve the material properties from error-polluted sample deformation maps. Using a simple model problem, the performances of both classical and neural network driven optimization are compared. When performed before the collection of experimental data, this evaluation can be very helpful in pinpointing potential problems with the envisaged experiments such as the need for a sufficient signal-to-noise ratio, particularly important when working with small tissue samples such as specimens cut from rodent bones or single bone trabeculae.

Algorithms↗

PubMedDate not supplied

[Human vital function monitoring as a system with hybrid intelligence].

Monitoring system is considered in this work as a reanimatologist-monitor-patient-medium system. This work is an upgrade to the previous concept of monitoring systems as systems with hybrid intelligence acting under variable conditions of object and medium. Human cardiorespiratory system was considered within the framework of the P. K. Anokhin theory of functional systems. The problem of resuscitation was formulated for this system and volume of required information was determined. Environment characteristics in resuscitation and surgery departments were considered. The requirements for monitor were formulated on the basis of analysis of these systems. The law of mutual adaptation of reanimatologist and monitor was put forward and safety problems associated with human factor were considered. Implementation of these principles in the MITAR 01-R-D is described.

Artificial Intelligence↗

PubMed2001

Mind over matter? II: implications for psychiatry.

OBJECTIVE: To explore concepts of causality within the mind and aetiology of psychiatric disorders in the light of the proposed formulation of the mind-brain problem. METHOD: Taking the two propositions of this formulation as 'first principles' a logical analysis is attempted. RESULTS AND CONCLUSIONS: Neural activity cannot in principle be regarded as causing mental activity, or vice versa. Causal processes are most coherently conceptualised in terms of the 'mind-brain' system. Determination of causal and aetiological effects will always necessitate consideration of contextual evidence. Because of the 'explanatory gap' between explanation in neurophysiological terms and 'mentalistic' terms, whenever formulation in mentalistic terms is possible this will carry greater explanatory power; that is, it will carry meaning in the way a neural formulation cannot.

Brain↗

PubMed2006

The use of topical diclofenac for pain in osteoarthritis of the knee: a review.

Osteoarthritis (OA) is a common complaint that affects millions of people worldwide. As there is no cure for OA, drug treatment is the main form of management. This can be achieved through the use of analgesics and anti-inflammatory drugs such as the NSAID diclofenac sodium. The chronic use of diclofenac sodium can lead to adverse gastrointestinal problems. The use of a topical formulation of diclofenac sodium aims to reduce this problem. Evidence from four randomized controlled trails of the efficacy and safety of topical diclofenac sodium as a method of pain relief for the treatment of OA of the knee is presented and discussed. Findings imply that topical diclofenac sodium is an efficacious and safe method of pain control in patients with OA of the knee.

Administration, Cutaneous↗

PubMed1987

AIDS, sexuality, and sexual control.

The AIDS epidemic is discussed in terms of its effect on general sexual attitudes and behavior of homosexual and bisexual men, then, in particular, on the issue of control over one's sexual behavior. Problems encountered in the formulation of the concept of sexual control are discussed along with relevant theoretical constructs. A group treatment program for homosexual and bisexual men with problems of sexual control is described, along with findings and discussions regarding the effect of such treatment on sexual behavior.

Acquired Immunodeficiency Syndrome↗

PubMed1988

Quality assurance in equipment ordering for the spinal cord-injured client.

Occupational therapy for spinal cord-injured clients is based on training in the use of adapted techniques and adapted equipment to optimize functioning. Two factors, the need for equipment to enhance the client's potential and the demand for cost containment in equipment ordering, spurred a quality assurance study of equipment ordering. Through a follow-up survey of persons who had received equipment while they were patients of the New England Regional Spinal Cord Injury Center, suspected problems were identified and defined. A plan was formulated and implemented to resolve the problems; then the outcomes of this plan were evaluated by a telephone survey 1 year later. This quality assurance study helped establish accountability for cost containment in equipment ordering based on the client's perceived need, the client's level of spinal cord injury, equipment durability, and the timeliness of ordering.

Cost Control↗

PubMed2006

Graphical models and point pattern matching.

This paper describes a novel solution to the rigid point pattern matching problem in Euclidean spaces of any dimension. Although we assume rigid motion, jitter is allowed. We present a noniterative, polynomial time algorithm that is guaranteed to find an optimal solution for the noiseless case. First, we model point pattern matching as a weighted graph matching problem, where weights correspond to Euclidean distances between nodes. We then formulate graph matching as a problem of finding a maximum probability configuration in a graphical model. By using graph rigidity arguments, we prove that a sparse graphical model yields equivalent results to the fully connected model in the noiseless case. This allows us to obtain an algorithm that runs in polynomial time and is provably optimal for exact matching between noiseless point sets. For inexact matching, we can still apply the same algorithm to find approximately optimal solutions. Experimental results obtained by our approach show improvements in accuracy over current methods, particularly when matching patterns of different sizes.

Algorithms↗

PubMedDate not supplied

[Evolution of life cycle: models based on optimization of energy allocation].

A brief history of optimization approach in modern evolutionary ecology is given and author's own results concerning life history evolution are considered in more details. The problem of evolutionary optimization is formulated in terms of mathematical theory of optimal control as a problem of optimal sharing of organism's resources between growth, reproduction, repair, and maintenance. The Malthusian parameter is used as optimality criterion. This approach allows, in particular, to give evolutionary ecological explanations for some well known empirical facts such as attenuation of growth with age (law of Bertalanffi), acceleration of ageing with age (law of Gompertz), human sexual dimorphism in mean lifespan, age and size of maturity.

Aging↗

PubMedDate not supplied

Computing the minimum recombinant haplotype configuration from incomplete genotype data on a pedigree by integer linear programming.

We study the problem of reconstructing haplotype configurations from genotypes on pedigree data with missing alleles under the Mendelian law of inheritance and the minimum-recombination principle, which is important for the construction of haplotype maps and genetic linkage/association analyses. Our previous results show that the problem of finding a minimum-recombinant haplotype configuration (MRHC) is in general NP-hard. This paper presents an effective integer linear programming (ILP) formulation of the MRHC problem with missing data and a branch-and-bound strategy that utilizes a partial order relationship and some other special relationships among variables to decide the branching order. Nontrivial lower and upper bounds on the optimal number of recombinants are introduced at each branching node to effectively prune the search tree. When multiple solutions exist, a best haplotype configuration is selected based on a maximum likelihood approach. The paper also shows for the first time how to incorporate marker interval distance into a rule-based haplotyping algorithm. Our results on simulated data show that the algorithm could recover haplotypes with 50 loci from a pedigree of size 29 in seconds on a Pentium IV computer. Its accuracy is more than 99.8% for data with no missing alleles and 98.3% for data with 20% missing alleles in terms of correctly recovered phase information at each marker locus. A comparison with a statistical approach SimWalk2 on simulated data shows that the ILP algorithm runs much faster than SimWalk2 and reports better or comparable haplotypes on average than the first and second runs of SimWalk2. As an application of the algorithm to real data, we present some test results on reconstructing haplotypes from a genome-scale SNP dataset consisting of 12 pedigrees that have 0.8% to 14.5% missing alleles.

Algorithms↗

PubMed2006

Research results have expiration dates: ensuring timely systematic reviews.

Time and timeliness are key issues in appraising and ensuring the clinical relevance of systematic reviews. Time considerations entering the systematic review process include the history of the clinical problem, disease, or treatment that is the target of the review, and the history of the research conducted to address it. These considerations guide: (i) formulation of the research problems and questions; (ii) setting of parameters for the search and retrieval of studies; (iii) determination of inclusion and exclusion criteria; (iv) appraisal of the clinical relevance of findings; (v) selection of the findings that will be synthesized; and (vi) interpretation of the results of that synthesis.

Humans↗

PubMed1987

Various administration forms of nitrates and their possibilities.

This article reviews the development and pharmacokinetics of a number of new dosage formulations (e.g. transdermal patches and buccal tablets) and new active substances (e.g. isosorbide 5-mononitrate) which have recently been introduced to overcome some of the problems inherent in conventional formulations of organic nitrates.

Administration, Cutaneous↗

PubMed1982

Toward a theory of clinical expertise.

We believe that the outline of a promising approach to the study of expert clinical problem-solving is emerging. This process involves collecting as verbal transcripts the thoughts of experienced clinicians engaged in simulated clinical tasks and analyzing these transcripts to formulate theories of problem-solving tactics and strategies. In turn, these theories are embodied in a computer program that simulates the problem-solving process. The computer program's response to fresh clinical problems can be compared with physician behavior in order to revise, refute, or confirm the problem-solving theories. A scientific understanding of the expert clinician's reasoning strategies could prove exceptionally useful in improving the way we teach and practice medicine and in developing practical computer aids for medical decision-making.

Clinical Competence↗

PubMedDate not supplied

A systems model for adaptation to somatic distress among cancer survivors.

Applied coping research has generally failed to fulfill its goal of providing an empirical basis for clinical interventions, and research on coping with cancer is no exception. This can be attributed in large measure to the wide gap between coping theory and coping research. Theories of stress and adaptation are complex systems formulations that present conceptual and methodological challenges and thus make testing comprehensive models difficult. The present paper reviews arguments for a microanalytic strategy through which researchers can increase coverage of relevant variables from broad systems models of stress and coping by concentrating their resources on selected, high-frequency, high-stress problems. The utility of this approach for formulating problem-specific systems models is illustrated using the example of coping with somatic distress among cancer survivors.

Adaptation, Psychological↗

PubMed2003

A software tool for specifying voxel models for dosimetry estimation.

Many dose estimation problems can be conveniently formulated in terms of finding the energy emitted and absorbed by a set of homogeneous volume elements (voxels) arranged in a rectilinear grid. The solution of these problems requires an accurate model of the source and target geometry to be established, whereupon conventional Monte Carlo simulation of radiation transport can be employed to determine energy deposition. A software application ("MrVoxel") has been developed to assist in the specification of the source and target models. This application includes tools for image segmentation and image registration (2D and 3D, intra- and inter-modality, interactive, and automatic). It employs a plug-in architecture to facilitate customization and future expansion: plug-ins can be written to perform image import and export as well as to implement specialized image processing routines. Using plug-ins, the package can, for example, import DICOM 3.10 files and export input files for a voxel-based Monte Carlo package. Standard dosimetric tools such as the geometric mean method, transmission based attenuation correction, and MIRD-style voxel dose kernel convolution are also implemented as plug-ins. MrVoxel was implemented on a Macintosh computer using a commercial software framework to produce a conventional document-centric application. Hence it includes useful features such as the ability to undo an operation or to save a processed image set at any point. This latter feature enables the production of a processing trail, to allow post-hoc auditing of the analysis process. This paper describes the MrVoxel application and its role in the analysis of a particular dosimetry problem.

Algorithms↗

PubMed2004

Prescribed error tolerances within fixed computational times for scattering problems of arbitrarily high frequency: the convex case.

We present a new algorithm for the numerical solution of problems of electromagnetic or acoustic scattering by large, convex obstacles. This algorithm combines the use of an ansatz for the unknown density in a boundary-integral formulation of the scattering problem with an extension of the ideas of the method of stationary phase. We include numerical results illustrating the high-order convergence of our algorithm as well as its asymptotically bounded computational cost as the frequency increases.

Journal Article↗