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PubMed2005

Robust mission design through evidence theory and multiagent collaborative search.

In this paper, the preliminary design of a space mission is approached by introducing uncertainties on the design parameters and formulating the resulting reliable design problem as a multiobjective optimization problem. Uncertainties are modelled through evidence theory and the belief, or credibility, that the successful achievement of mission goals is maximized along with the reliability of constraint satisfaction. The multiobjective optimization problem is solved through a novel algorithm based on the collaboration of a population of agents in search for the set of highly reliable solutions. Two typical problems in mission analysis are used to illustrate the proposed methodology.

Journal Article↗
PubMed1995

The limits of empirical studies on research ethics.

The results of empirical research in psychology and psychiatry are increasingly being used to formulate as well as understand problems at the interface of law and psychiatry. There has been a proliferation of studies, such as the determinants of individual competence or threat to self or others, the results of which are influencing policy and legislative decisions as well as buttressing holdings in court cases. In this article, I explore the issues of interpretation of epidemiological studies, particularly the role of ideological positions on the design and results of empirical findings, the importance of the way data are interpreted, and the role of ideologies in the way research findings are presented to provide support for policy positions. Two levels of analysis are involved in determining the validity of a study. The first addresses the questions of whether the study meets the statistical and epidemiological requirements for reliable results. These include considerations such as the appropriateness of the study design and methods for gathering and interpreting data. The second focuses on the underlying framework of the study. This involves factors such as the perspectives and values of those conducting the study, the explicit and implicit dominating ideologies where they operate, and the extent to which the study is constructed to reaffirm specific ideologies. This level of analysis is essential for disclosing the influences of ideologies on the results of studies and the way in which data are interpreted. In this article, I try to demonstrate through critiques of selected studies that the first stage of analysis is insufficient without an examination of underlying preconceived values to establish the meaningfulness of results.

Aged↗
PubMed1999

HPLC analysis of juzen-taiho-to and its variant formulations and their antimetastatic efficacies.

Our previous study demonstrated that the oral administration of Juzen-taiho-to resulted in a significant inhibition of the liver metastasis of colon 26-L5 cells as compared with the untreated control, without side effects. We attempted to investigate the relationship between the HPLC pattern (referred to as the fingerprint) of the formulation and its component crude drugs and the inhibition of tumor metastasis in order to obtain the optimal efficacy and constant quality of the formulation. Two Juzen-taiho-to formulations (batches #1 and #2), which were individually prepared using the same 10 crude drugs and the same preparation procedure, showed similar anti-metastatic effects and absorbance patterns by HPLC analysis. Some variant formulations of Juzen-taiho-to, in which one crude drug was substituted with other crude drugs from different sources or places of origin, exhibited reduced efficacy as compared with the original formulation, as well as differences in the fingerprint pattern compared with the original formulation. Juzen (Naimo-Ogi-->Kibana-Ogi), a variant formulation with the substitution of Astragali radix of a different origin and place of harvest, showed significant inhibition of the liver metastasis of tumor cells and a HPLC fingerprint pattern similar to that of the original formulation. Thus, HPLC fingerprint analysis of Kampo medicines may provide a useful basis for obtaining their optimal efficacy as well as constant quality of the formulation, although it has some problems and limitations, such as detectability by and sensitivity to UV absorbance.

Animals↗
PubMed1998

Range estimation by optical differentiation.

We describe a novel formulation of the range recovery problem based on computation of the differential variation in image intensities with respect to changes in camera position. This method uses a single stationary camera and a pair of calibrated optical masks to measure this differential quantity directly. We also describe a variant based on changes in aperture size. The subsequent computation of the range image involves simple arithmetic operations and is suitable for real-time implementation. We present the theory of this technique and show results from a prototype camera that we have constructed.

Humans↗
PubMed2000

Network approaches to two-dimensional phase unwrapping: intractability and two new algorithms.

Two-dimensional (2-D) phase unwrapping, that is, deducing unambiguous phase values from a 2-D array of values known only modulo 2pi, is a key step in interpreting data acquired with synthetic aperture radar interferometry. Noting the recent network formulation of the phase unwrapping problem, we apply here some well-established ideas of network theory to formalize the problem, analyze its complexity, and derive algorithms for its solution. It has been suggested that the objective of phase unwrapping should be to minimize the total number of places where unwrapped and wrapped phase gradients differ. Here we use network constructions to show that this so-called minimum L0-norm problem is NP-hard, or one that complexity theory suggests is impossible for efficient algorithms to solve exactly. Therefore we must instead find approximate solutions; we present two new algorithms for doing so. The first uses the network ideas of shortest paths and spanning trees to improve on the Goldstein et al. residue-cut algorithm [Radio Sci. 23, 713 (1988)]. Our improved algorithm is very fast, provides complete coverage, and allows user-defined weights. With our second algorithm, we extend the ideas of linear network flow problems to the nonlinear L0 case. This algorithm yields excellent approximations to the minimum L0 norm. Using interferometric data, we demonstrate that our algorithms are highly competitive with other existing algorithms in speed and accuracy, outperforming them in the cases presented here.

Algorithms↗
PubMed2004

On the optical theory of photoelastic tomography.

In recent years many authors have considered the possibility of using tomography for nondestructive determination of three-dimensional stress fields. A natural starting point for this is integrated photoelasticity. The problem is complicated since the stress field is a tensor field, and in the general case in integrated photoelasticity the relationships between the measurement data and the parameters of the stress field are non-linear. To elucidate these relationships, we have systematically studied the propagation of polarized light in an inhomogeneous birefringent medium. The inverse problem of integrated photoelasticity is formulated in the general form, and particular cases in which the polarization transformation matrix is exactly determined by integrals of the stress tensor components are considered. The possibility of using the Radon inversion for approximate determination of the normal stress field in an arbitrary section of the test object is outlined.

Journal Article↗
PubMed2006

Strategic analysis for sustainable urban river aquatic environment using the system dynamic approach.

A sustainable aquatic environment, which relates to the issues of pollution mitigation and ecological restoration, is one of the important indicators of the vitality and prosperity of a city. Traditionally, resort to engineering efforts is always the first priority in dealing with such problems. Nevertheless, treated as an integrated system, the nature of the problem should involve many aspects including economic, ecological, environmental, and engineering factors. Meanwhile, the special feature of the time-dependent state has also made such a system a dynamic and complex problem. The current research has employed the concepts of integrated assessment trying to aggregate related studies and tackling the problem as a complete system. With the aid of the system dynamic modeling tool, which is capable of dealing with dynamic and complex problems, the simulation model was formulated following the macrostructure of system behavior. Various strategies for improving the sustainability of the aquatic environment in Love River, Kaohsiung, Taiwan have been evaluated. The decision makers are therefore allowed to choose more effective strategies based on the integrated perspectives.

Cities↗
PubMed2005

[Team communication needed in treatment for fixed prosthesis. 2) Opinion from dental technician's standpoint].

The fabrication of a fixed prosthesis is influenced by the communication between the dentist and the laboratory technician. Especially for tooth-colored restoration of anterior teeth, the laboratory technician has the difficult task of understanding the shade selected by the dentist and reproducing it in the final restoration. Conventional shade analysis techniques using the Vita shade guide often result in subjective analysis and a resultant miscommunication of color. Over the years, many different techniques including picture-taking, drawing of diagrams, and using multiple shade guides have been formulated to help overcome this problem. Recently, digital shade analysis systems have been designed to eliminate the subjectivity of color analysis and provide precise information for laboratory buildup and fabrication. However, even these techniques have not completely erased the difficulties involved in communicating the choice of the proper shade for tooth-colored restoration. Many dentists are only familiar with techniques they were taught in dental school and/or their residency program, and they are unaware of other, superior methods that can be used. This review introduces various shade analysis systems that can be performed in dental clinical practice. Further, it highlights the importance of communication between the dentist, technician, and patient for the fabrication and delivery of aesthetic restorations.

Color↗
PubMed1991

Conventional diagnostic nomenclature versus multimodal assessment.

Standard psychiatric diagnoses (e.g., DSM-III-R) are compared with multimodal assessment and problem identification (i.e., BASIC I.D. formulations. Two case comparisons are presented as an heuristic to illustrate the way in which the multimodal framework promotes diagnostic precision and enhances clinical decision-making.

Depressive Disorder↗
PubMed1976

A discriminant analysis approach to the identification of human chromosomes.

The identification of the various types of the 46 chromosomes in a normal human cell is formulated as a discriminant analysis problem. Derived are expressions for posterior probabilities, and rules are given for identification where the number of chromosomes of each type is exactly known. The resulting model is applied to experimental data from chromosomes of the Denver B-group. The results using the developed model compare favorably with those of the standard discriminant analysis approach.

Chromosomes↗
PubMed2002

Fractal dimensions of human brain cortex vessels during the fetal period.

BACKGROUND: Fractal dimensions always involve some averaging with respect to the given geometrical object. The classical geometrical description includes overly detailed geometrical information, rendering the precise formulation of equations ineffective. The problems associated with the functionality and growth of biological systems according to their observed geometrical shape require a specific approach. MATERIAL/METHODS: The material consists of 50 brains, 4th to 8th month of fetal life, length C.-R. 83-220 mm. The material was examined using the Pickworth method, computer image analysis (Imtronic, Scion for Windows 1998, and Elf v. 4.2), and fractal analysis. Various transformations were applied: numeric filters, statistical filters, binary geometrical transformations, arithmetical operations. Fractal analysis employs the 'box-counting' fractal dimension. RESULTS: The cortex vein net maintains the fetal character, with a large number of anastomoses, also present in adults. The size of cortex branches amounts to 100-200 microm. The reduction of some of the anastomoses during the early stages of evolution comes from an increase in the vessels' caliber. During the 4th month, the fractal dimension is 1.26, increasing to 1.53 at month 5. Rapid growth of the fractal dimension has been observed until the 6th and 7th months. This means an increased complexity level and feed volume in the brain. CONCLUSIONS: Fractals constitute a promising and effective tool to estimate the structures of brain vessels. The fractal dimension varies during the fetal period. This shows the close correspondence between the structure and functionality.

Algorithms↗
PubMed2002

Joint effect of genes and environment distorted by selection biases: implications for hospital-based case-control studies.

The hospital-based case-control design enhances the response rates in studies that require the collection of biological samples from all of the participants. There are simple, established criteria for selecting controls so as to estimate the effect of a single factor without bias, but the analogous requirements for assessing an interaction are less clear. We derive these conditions by calculating the potential bias from selecting controls who were admitted for treatment of diseases related to either or both of the exposures of interest, designated as a gene variant (G) and an environmental agent (E). There is no bias in the estimate of the effect of E when G is associated with the control condition, whether causally or because of confounding. There is no bias in estimating multiplicative interaction between G and E for the disease of interest when there is no multiplicative G-E interaction for the control disease, even when the control condition is caused by G or E; if a mixture of several control diseases are used, however, the absence of G-E interaction in each individual disease does not ensure a lack of overall bias when controls are pooled. Hospital control designs are much less robust for assessing additive interaction. We conclude that the ideal control disease in a hospital-based study of gene-environment interaction is not caused by either G or E and that choosing controls from several conditions to act as a combined control group is a useful strategy. This formulation extends to the general problem of distortion of joint effects from selection biases or confounding.

Case-Control Studies↗
PubMed1988

Royal Decree No. 1339/1987 on channels of institutional participation for Spaniards resident abroad, 30 October 1987.

This Decree establishes Councils of Resident Spaniards in consular districts with at least 700 absent voters. The activities of the Councils are to be developed around 1) civil and labor rights of Spaniards in consular districts under international law; 2) the insertion of Spanish students in the country's educational system, actions that under local or international law can be undertaken to ensure the maintenance of cultural ties to Spain, and, in general, typical activities abroad that provide education about Spain; 3) the participation of Spanish residents in the political life of Spain, in conformity with Spanish legislation, legislation of the country of residence, and international law; and 4) social and cultural actions favoring Spaniards. The Decree also sets forth the structure and functions of the General Emigration Council, which was established by Article 8.5 of Royal Decree No. 530/1985 of 8 April 1985. Among its functions are the following: 1) to carry out research on questions and problems affecting emigrants; 2) to formulate proposals and recommendations with respect to the objectives and the application of the principles inspiring migration policy; 3) to keep informed of the actions of administrative agencies competent in this matter; and 4) to approve regulations for the functioning of the Council.

Culture↗
PubMed2003

Efficient therapeutic gene delivery after systemic administration of a novel polyethylenimine/DNA vector in an orthotopic bladder cancer model.

Successful systemic gene therapy has been hindered by vector-related limitations, including toxicity and inefficient gene delivery to tumor cells after i.v. administration. To circumvent these problems, we developed a novel formulation between the polycation polyethyleneimine and DNA that mediates high-level tumor cell transduction in vitro and efficient i.v. gene delivery in that greater reporter gene expression occurred in tumor than in lung. Strikingly, administration of just 6 micro g of the polyethyleneimine/DNA-p53 vector every 3 days for 3 weeks indicated restoration of normal cell cycle regulation and apoptotic mechanisms as demonstrated by efficient p53 expression, increased apoptosis, and a 70% reduction in tumor size in an orthotopic bladder cancer model. This novel vector formulation represents a new method to increase i.v. delivery of genes to tumors.

Animals↗
PubMedDate not supplied

[Antiviral chemotherapy in pediatrics--its present and prospects].

Authors discuss the general aspects of viral infections and the principles of antiviral chemotherapy. First section deals with the stages, the types of viral infections and the basic principles for action of antiviral drugs. Authors review also the up-to-date situation of antiviral therapy in pediatrics, the problem of resistant strains and formulate the expected progress in the field of antiviral chemotherapy.

Antiviral Agents↗
PubMed1992

[6 theses on environmental problems].

Many of the environmental problems caused by human activity show such a complexity that the potentially dangerous mechanisms are either not understood or not known in the public. However, a change of attitude to the public can only be achieved if the interdependence between personal habits and their environmental effects are popular. After a short discussion of the mechanisms of the most important climatic problems, six theses will be formulated which could serve as basis for discussions and starting point for changes in our behavior affecting the environment.

Air Pollutants↗
PubMedDate not supplied

Effect of clinical settings on the utilization of nurse practitioners.

In this study, 143 medical and pediatric nurse practitioners in 61 agencies identified problems in role implementation and formulated recommendations for more effective utilization in clinical settings which employ, or plan to employ, nurse practitioners. Physician-intensive settings appeared to utilize nurse practitioners least effectively and more practitioners left such settings, citing inability to implement the role, than did practitioners employed by other types of health agencies. Different kinds of health agencies integrated and implemented the role at different rates.

Adult↗
PubMed1989

Micellar enzymology: potentialities in fundamental and applied areas.

Micellar enzymology, a new trend in molecular biology, studies catalysis by enzymes entrapped in hydrated reversed micelles of surfactants (phospholipids, detergents) in organic solvents. In this review, the key research problems of micellar enzymology are formulated and examples of biocatalysis in microheterogeneous media are discussed. In particular, new applications are presented of micellar enzymology in fine organic syntheses, in clinical and chemical analyses (bioluminescence and enzyme immunoassays), in bioconversion of energy and mass, in therapy (engineering of new drugs capable of targeted penetration into cells), as well as in biotechnology (processes using nanogranulated or nanocapsulated enzymes).

Animals↗