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At least 19 recordsLinked to original sources
PubMed1992

[The configuration of a video signal digitalizing system used in astronomy for radiological applications].

A digital system of video signals of astronomical use was developed to be applied in the field of radiology. The images were obtained from radiologic films by means of a standard video camera. The minimal specifications of the digital images for use in radiology are as follows: a) 2.5 lpm spatial resolution, b) a digital resolution of 8 bits (256 gray levels). Images (194 by 154 mm in size) can be obtained. The software processing was adapted for treatment of the images in radiology.

Astronomy↗
PubMed1991

From radio-astronomy to medical imaging.

A common thread in much of the medical imaging that has developed over the past 20 years has been the Fourier transform. It was Richard Bates' interest in radio-interferometry, as well as his fascination with problems of medical imaging that prompted an initial interest in applying Fourier techniques to medical imaging in general and to Computed Tomography in particular. This resulted 20 years ago in one of the earliest technical papers advocating Fourier techniques for reconstructing cross-sections from radiographic projections (Bates and Peters, NZ J Science 14:883-896, 1971). Since those early days, medical imaging has explored into a multi-billion dollar industry. The CT scanner has become the workhorse imaging modality in the radiology department, while its more recent relative, the MR scanner, is rapidly gaining ground as a technique of even greater importance. Richard Bates, with his team of "Medical Imagers" was a very significant force in the development of the field of Medical Imaging as we know it today. This paper attempts to chronicle the genesis of this process from the personal perspective of the author.

Diagnostic Imaging↗
PubMed1991

Extrapolation by proximate inference.

Scientific extrapolation, as in astronomy, is different from legal or regulatory extrapolation, as in arriving at acceptably safe levels of agents. Scientific and technological information is required in the latter process, but scientists fail to contribute when they respond to legal and regulatory questions by attempting purely scientific extrapolation.

Animals↗
PubMed1992

Blind deconvolution of quantum-limited incoherent imagery: maximum-likelihood approach.

Previous research presented by the author and others into maximum-likelihood image restoration for incoherent imagery is extended to consider problems of blind deconvolution in which the impulse response of the system is assumed to be unknown. Potential applications that motivate this study are wide-field and confocal fluorescence microscopy, although applications in astronomy and infrared imaging are foreseen as well. The methodology incorporates the iterative expectation-maximization algorithm. Although the precise impulse response is assumed to be unknown, some prior knowledge about characteristics of the impulse response is used. In preliminary simulation studies that are presented, the circular symmetry and the band-limited nature of the impulse response are used as such. These simulations demonstrate the potential utility and present limitations of these methods.

Algorithms↗
PubMed1992

Concurrent phenomena of science and history in the 17th century and their essential interdependence.

The explanation for the explosion of science in the 17th century lies in history and medical historiography. Without this approach, it becomes fantasy, accidents, or success stories. Sigerist grasped the essential interdependence of science and history, and had no need for devised reasons or speculation. He realized that once the dark night of the Middle Ages was over, the sciences arose with undreamt of force and accelerated development. The advances in astronomy, mathematics, mechanics, and experimental science benefitted a society developing in seafaring, manufacture, and trade in the 17th century. Sigerist's views make the scientific explosion understandable in human and social terms. He did not overlook the capabilities of some extraordinary individuals, such as Paracelsus (1493-1541), to shape the course of medicine, nor the importance of the mechanistic philosophy in the 17th century. Man makes history and science; hence, we find concurrent phenomena of history and science essentially interdependent. The spirit of experimental science of 17th century England was inspired by the new needs of commercial enterprise for more means of transportation and communication. Likewise, the interest in the mechanics of the pump for waterworks and for the drainage of swamps led Harvey to think of the heart as a pump, and to explain the circulation of the blood in terms of its functioning.

England↗
PubMed1991

Assessing the scientific strength of Chile.

We use analysis of co-citation and relative citation rates to assess the scientific strength of Chile as compared with other developing countries and to evaluate the potential for increased international collaboration between Chile and the United States in science and engineering. Co-citation is the citation of two scientific papers by a third paper. By examining frequency and patterns of co-citation, the intellectual structure and evolution of scientific disciplines and research specialties can be traced. Chile is especially "strong", as defined by the co-citation model we employ, in biomedicine and clinical medicine, and in astronomy. A relative citation rate is the ratio of the number of citations a paper receives to the average number of citations for all papers published in the same journal over time. Analysis of relative citation rates of papers published by authors with Chilean addresses show that Chilean physics, including earth and space sciences, is of unusually high quality, considerably higher than any other developing country and comparable to several industrialized countries. We conclude that Chile's scientific capacity is advanced enough to absorb and benefit significantly from strategic additions to the country's resources and capabilities for research. These would include increases in: exchanges of researchers in specific fields with U.S. and other Latin American academic, industrial, and government scientists and engineers; training at outstanding U.S. and Latin American institutions; laboratory equipment, computer time, communications links, and library materials; and funding from U.S. and international organizations. It is also apparent that Chile is strong enough in certain fields to cooperate with the U.S. in mutually beneficial international efforts.

Authorship↗
PubMed1976

The impetus to scientific psychology: a recurrent pattern.

In the nineteenth century, the personal equation, which concerned individual differences in the accuracy of astronomical observations, provided an impetus to the development of experimental psychology. During the first decade of Wundt's laboratory, the measurement of the duration of mental acts received more experimental attention than any other subject. Twentieth century developments in the theoretical physics have stimulated interest in the nature of mental operations and conceptual transformations, a topic which is currently receiving increased attention in psychology. It is suggested that the history of psychology may provide a useful data source for additional work in this area.

Astronomy↗
PubMed1976

General constraints on the Viking biology investigation.

The Viking biological investigation will be conducted in the face of a number of constraints. Problems are created because of the inherent engineering of the instrument, communication constraints and other factors.

Astronomical Phenomena↗
PubMed1977

The origin of the planetesimal theory.

T. C. Chamberlin suggested in 1897, on the basis of geological and climatological arguments, that the planets were formed by accretion of cold solid partices. With F. R. Moulton he developed convincing arguments against the Laplace nebular hypothesis and published a comprehensive 'planetesimal theory' of the origin of the solar system in 1905. The Chamberlin-Moulton theory has current as well as historical interest.

Astronomy↗
PubMed1978

Of discoveries.

Explore the source record for details and available documents.

Astronomical Phenomena↗
PubMed1992

Children's judgments in theory choice tasks: scientific rationality in childhood.

The current research examined whether children could use certain metaconceptual criteria such as the range of explanation, non-ad hocness of explanation, empirical consistency, and logical consistency to choose between competing accounts of physical phenomena. The tasks were constructed so that the conceptual content of the explanations to be evaluated was either consistent, inconsistent, or neutral with regard to children's prior knowledge. It was found that even 7-year-olds could use metaconceptual criteria such as the range, empirical consistency, and logical consistency of theories when the theories did not violate their beliefs. However only older children (11-year-olds) showed a systematic preference for non-ad hoc theories over ad hoc ones. The findings are consistent with recent work in the philosophy of science showing that, in evaluating theoretical alternatives, scientists are influenced by their prior beliefs about the domain being considered. This research demonstrates that even young children share some of the cognitive underpinnings of scientific rationality that scientists do.

Astronomical Phenomena↗