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Results for “Computers, Hybrid”

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At least 163 records · Page 9Linked to original sources
PubMed1996

Hybrid eye tracking for computer-aided retinal surgery.

We describe initial results of a new hybrid digital and analog design for tracking the retina and controlling the laser beam. The results demonstrate tracking rates which exceed the equivalent of 50 degrees per second in the eye, with automatic lesion pattern creation and robust loss of lock detection. Robotically-assisted laser surgery to treat conditions such as diabetic retinopathy, macular degeneration, and retinal tears can now be realized under clinical conditions with requisite safety using standard video hardware and inexpensive optical components.

Eye Movements↗
PubMed2000

Web-based continuing medical education. (II): Evaluation study of computer-mediated continuing medical education.

BACKGROUND: Over the years, various distance learning technologies and methods have been applied to the continuing medical education needs of rural and remote physicians. They have included audio teleconferencing, slow scan imaging, correspondence study, and compressed videoconferencing. The recent emergence and growth of Internet, World Wide Web (Web), and compact disk read-only-memory (CD-ROM) technologies have introduced new opportunities for providing continuing education to the rural medical practitioner. This evaluation study assessed the instructional effectiveness of a hybrid computer-mediated courseware delivery system on dermatologic office procedures. METHODS: A hybrid delivery system merges Web documents, multimedia, computer-mediated communications, and CD-ROMs to enable self-paced instruction and collaborative learning. Using a modified pretest to post-test control group study design, several evaluative criteria (participant reaction, learning achievement, self-reported performance change, and instructional transactions) were assessed by various qualitative and quantitative data collection methods. RESULTS: This evaluation revealed that a hybrid computer-mediated courseware system was an effective means for increasing knowledge (p < .05) and improving self-reported competency (p < .05) in dermatologic office procedures, and that participants were very satisfied with the self-paced instruction and use of asynchronous computer conferencing for collaborative information sharing among colleagues.

Adult↗
PubMed2005

Very large swelling in hybrid frameworks: a combined computational and powder diffraction study.

Using a combination of simulations and powder diffraction, we report here the study of the very large swelling of a three-dimensional nanoporous iron(III) carboxylate (MIL-88) which exhibits almost a reversible doubling (approximately 85%) of its cell volume while fully retaining its open-framework topology. The crystal structure of the open form of MIL-88 has been successfully refined and indicates that atomic displacements larger than 4 angstroms are observed when water or various alcohols are adsorbed in the porous structure, revealing an unusually flexible crystallized framework. X-ray thermodiffractometry shows that only a displacive transition occurs during the swelling phenomenon, ruling out any bond breaking.

Journal Article↗
PubMed2003

[Studies on somatostatin mRNA expression in frontal cortex of diabetic rats model].

To study the changes of somatostatin (SST) in frontal cortex of the brain of quick streptozotocin-induced diabetes rats. We established the quick-diabetic rats model by injecting streptozotocin intraperitoneally with 60 mg/kg and compared the changes of SST in frontal cortex of diabetic model with normal rats by using in situ hybridization and computer image analysis. The number, light density and the average area of positive cells in frontal cortex of diabetic model were reduced significantly in comparison with those of normal rats (P < 0.01). These results indicated that the decline of SST mRNA expression in frontal cortex may relate to chronic diabetes encephalopathy.

Animals↗
PubMed2004

Computational identification of antisense oligonucleotides that rapidly hybridize to RNA.

The ability of a computational model to determine the relative rate of hybridization between anti-sense oligonucleotides and RNA was tested using HIV-1 tat mRNA. The model, which was based on the assumptions that hybridization is a second-order reaction and that early in the hybridization reaction the concentrations of intermediates are approximately constant (steady-state), allows calculation of a rate factor that is proportional to the reaction constant. Formation of oligodeoxynucleotide (ODN)-RNA hybrid, detected by RNase H-dependent cleavage, increased nearly linearly during an initial incubation period, consistent with the steady-state approximation. The initial hybridization rate increased linearly with substrate RNA concentration and with ODN concentration, indicating a second-order reaction. The logarithm of the second-order reaction constant, determined from the initial rate for hybridization between tat mRNA and 16 ODNs targeted to various sites, was linearly related to the logarithm of the calculated rate factor (r = 0.83, p < 0.001). Thus, the rate factor can be used to identify rapidly hybridizing antisense sequences using target nucleotide sequence information.

Computational Biology↗
PubMed1977

[Computer processing of radioisotope images. Hybrid processing system].

A hydrid type image file and processing system are devised by the author to file and the radioisotope image processing with analog display. This system has some functions as follows: 1) Ten thousand images can be stored in 60 feets length video-tape-recorder (VTR) tape. 2) Maximum of an image on the VTR tape is within 15 sec. 3) An image display enabled by the analog memory, which has brightness more than 15 gray levels. 4) By using the analog memories, effective image processing can be done by the small computer. 5) Many signal sources can be inputted into the hybrid system. This system can be applied many fields to both routine works and multi-purpose radioisotope image processing.

Computers, Hybrid↗
PubMed1994

Simulation of marker assisted selection in hybrid populations.

A computer model is developed that simulates Marker Assisted Selection (MAS) in a population produced by a cross between two inbred lines. Selection is based on an index that incorporates both phenotypic and molecular information. Molecular markers contributing to the index and their relative weights are determined by multiple regression of individual phenotype on the markers. The model is applied to investigate the efficiency of MAS as affected by several factors including total number of markers in the genome, number of markers contributing to the index, population size and heritability of the character. It is demonstrated that selection based on genetic markers can effectively utilize the linkage disequilibrium between genetic markers and QTLs created by crossing inbred lines. Selection is more efficient if markers contributing to the index are re-evaluated each generation than if they are evaluated only once. Increasing the total number of markers in the genome as well as the number of markers contributing to the index does not necessarily result in a higher efficiency of selection. Moreover, too many markers may result in a weaker response to selection. Population size is shown to be the most important factor affecting the efficiency of MAS.

Animals↗
PubMed1993

Designing a connectionist network supercomputer.

This paper describes an effort at UC Berkeley and the International Computer Science Institute to develop a supercomputer for artificial neural network applications. Our perspective has been strongly influenced by earlier experiences with the construction and use of a simpler machine. In particular, we have observed Amdahl's Law in action in our designs and those of others. These observations inspire attention to many factors beyond fast multiply-accumulate arithmetic. We describe a number of these factors along with rough expressions for their influence and then give the applications targets, machine goals and the system architecture for the machine we are currently designing.

Algorithms↗
PubMedDate not supplied

Fundamental study of automatic cytoscreening for uterine cancer. IV. Sample requirements for CYBEST and simulation test of cell dispersion.

The preparation of samples with good cell dispersion and without cell overlapping is a particularly important problem, whether for image processing systems or for flow systems. Simulation tests were carried out to estimate a cell density with good cell dispersion and a minimum number of overlapping cells. A little less than 50 cells per mm2 was disclosed to show a condition of sufficient cell dispersion. By microscopical observation and counting of the malignant cells using ten cases of uterine cervical carcinoma, it was found that in most instances over 50 malignant cells were contained in 20,000 to 40,000 cells on the smears. When the cell density is approximately 50 per mm2, the scanning area of the CYBEST of 40 X 20 mm may contain up to 40,000 cells. The probability that such a number of cells contains malignant cells is extremely high, in fact, nearly 100 per cent. By field tests, it was experimentally confirmed that these cell densities are very adequate for the function of the CYBEST.

Autoanalysis↗
PubMedDate not supplied

Fundamental study of automatic cytoscreening for uterine cancer. V. Data analysis for imporvement of CYBEST.

The particles selected by CYBEST as "abnormal cells" at the stage of coarse scanning were examined by direct microscopy to determine whether they were actural cells or not. Approximately 20 to 30 per cent of these were cell clusters and/or clumped leukocytes and red cell or specks of dust. Such incidents interfered considerably with a precise cytologic assessment. To eliminate this problem by means of a software algorithm, experiments were carried out setting thresholds for cell feature values. When the values obtained by machine measurement exceeded the theshold values the particles concerned were automatically disregarded, as interfering indidents, at the state of the coarse scanning. The approach was found to have substantial value in the operation of CYBEST as a pescreening device.

Autoanalysis↗