32,518 research outputs found

    The power of neural nets

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    Implementation of the Hopfield net which is used in the image processing type of applications where only partial information about the image may be available is discussed. The image classification type of algorithm of Hopfield and other learning algorithms, such as the Boltzmann machine and the back-propagation training algorithm, have many vital applications in space

    A technique for correcting ERTS data for solar and atmospheric effects

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    The author has identified the following significant results. Based on processing ERTS CCTs and ground truth measurements collected on Michigan test site for January through June 1973 the following results are reported: (1) atmospheric transmittance varies from: 70 to 85% in band 4, 77 to 90% in band 5, 80 to 94% in band 6, and 84 to 97% in band 7 for one air mass; (2) a simple technique was established to determine atmospheric scattering seen by ERTS-1 from ground-based measurements of sky radiance. For March this scattering was found to be equivalent to that produced by a target having a reflectance of 11% in band 4, 5% in band 5, 3% in band 6, and 1% in band 7; (3) computer ability to classify targets under various atmospheric conditions was determined. Classification accuracy on some targets (i.e. bare soil, tended grass, etc.) hold up even under the most severe atmospheres encountered, while performance on other targets (trees, urban, rangeland, etc.) degrades rapidly when atmospheric conditions change by the smallest amount

    Computer Mapping of Water Quality in Saginaw Bay with LANDSAT Digital Data

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    The author has identified the following significant results. LANDSAT digital data and ground truth measurements for Saginaw Bay (Lake Huron), Michigan, for 31 July 1975 were correlated by stepwise linear regression and the resulting equations used to estimate invisible water quality parameters in nonsampled areas. Chloride, conductivity, total Kjeldahl nitrogen, total phosphorus, and chlorophyll a were best correlated with the ratio of LANDSAT Band 4 to Band 5. Temperature and Secchi depth correlate best with Band 5

    Simulation of Thematic Mapper performance as a function of sensor scanning parameters

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    The investigation and results of the Thematic Mapper Instrument Performance Study are described. The Thematic Mapper is the advanced multispectral scanner initially planned for the Earth Observation Satellite and now planned for LANDSAT D. The use of existing digital airborne scanner data obtained with the Modular Multispectral Scanner (M2S) at Bendix provided an opportunity to simulate the effects of variation of design parameters of the Thematic Mapper. Analysis and processing of this data on the Bendix Multispectral Data Analysis System were used to empirically determine categorization performance on data generated with variations of the sampling period and scan overlap parameters of the Thematic Mapper. The Bendix M2S data, with a 2.5 milliradian instantaneous field of view and a spatial resolution (pixel size) of 10-m from 13,000 ft altitude, allowed a direct simulation of Thematic Mapper data with a 30-m resolution. The flight data chosen were obtained on 30 June 1973 over agricultural test sites in Indiana

    Laparoscopic bilateral gonadectomy in a case of turner syndrome with 45XO/46XY genotype

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    Turner syndrome is one of the common chromosomal aberrations which manifests in a female as multiple phenotypic disorders usually presenting as a case of primary amenorrhea. Many of these patients display mosaicism on karyotyping and a presence of Y chromosomal material indicates high risk of gonadoblastoma and gonadectomy is indicated which is best achieved by laparoscopy. This is a case of 21-year-old female phenotype referred as a case of primary amenorrhea diagnosed as Turner syndrome with 46XY mosaicism. Laparoscopic bilateral salpingoophorectomy was done. In patients of primary amenorrhea karyotyping should be evaluated and if Y chromosome detected these patients should be subjected to gonadectomy after proper risk counselling about malignancy

    Laparoscopic management of heterotopic pregnancy in an IVF conception

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    Heterotopic Pregnancy cases are on the rise in the era of Artificial Reproductive Techniques and managing these pregnancies can be challenging especially in safeguarding the precious intrauterine pregnancy. These were traditionally managed by laparotomy and there are few cases reported wherein salpingectomy is done laparoscopically. We would like to report this case of a 7 weeks intrauterine pregnancy with 5 weeks tubal ectopic treated by laparoscopic salpingectomy under spinal anaesthesia while safeguarding the intrauterine viable gestation. In the light of increased incidence of abnormal implantations and growing demand and expertise of minimally invasive surgeries, laparoscopy is the treatment of choice for heterotopic pregnancies, especially in the interest of the intrauterine pregnancy

    Large-amplitude chirped coherent phonons in tellurium mediated by ultrafast photoexcited carrier diffusion

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    We report femtosecond time-resolved reflectivity measurements of coherent phonons in tellurium performed over a wide range of temperatures (3K to 296K) and pump laser intensities. A totally symmetric A1_{1} coherent phonon at 3.6 THz responsible for the oscillations in the reflectivity data is observed to be strongly positively chirped (i.e, phonon time period decreases at longer pump-probe delay times) with increasing photoexcited carrier density, more so at lower temperatures. We show for the first time that the temperature dependence of the coherent phonon frequency is anomalous (i.e, increasing with increasing temperature) at high photoexcited carrier density due to electron-phonon interaction. At the highest photoexcited carrier density of \sim 1.4 ×\times 1021^{21}cm3^{-3} and the sample temperature of 3K, the lattice displacement of the coherent phonon mode is estimated to be as high as \sim 0.24 \AA. Numerical simulations based on coupled effects of optical absorption and carrier diffusion reveal that the diffusion of carriers dominates the non-oscillatory electronic part of the time-resolved reflectivity. Finally, using the pump-probe experiments at low carrier density of 6 ×\times 1018^{18} cm3^{-3}, we separate the phonon anharmonicity to obtain the electron-phonon coupling contribution to the phonon frequency and linewidth.Comment: 22 pages, 6 figures, submitted to PR

    Rapid identification of E. coli bacteriophages using mass spectrometry

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    Objective: The current increasing interest in the application of mass spectrometry, in particular MALDI-TOF MS, to identification of bacteria and fungi calls for a need to utilise this technology for identification of other infectious agents such as viruses. The aim of the present study was to develop a rapid and reliable mass spectrometry-based proteomic method for identification of Escherichia coli phages. Methods: The approach was based on rapid in-solution tryptic digestion of suspensions of plaque-purified bacteriophage followed by mass spectral analysis. Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and liquid chromatography – tandem mass spectrometry (LC-MS) were used to analyse the tryptic digests. Processing of tandem mass spectrometry data and interpretation of results were achieved using Mascot software and the Swiss-Prot database. Results: Five bacteriophage species (Enterobacteria phages P2, T4, T5, T7 and Lambda) isolated in E. coli cultures were identified. The viral proteins were identified from a complex mixture of host bacterial proteins. In addition, using a single ion monitoring method, a Lambda prophage derived protein was also identified. Conclusion: The data obtained demonstrate that LC-MS/MS can be used for accurate identification of E.coli- specific bacteriophages in both lytic and lysogenic cycles Keywords: Bacteriophage virus; Mass-spectrometry; Liquid chromatography; MALDI; LC-MS/MS; Lytic; Lysogenic; Enterobacteria; E.coli; Phage; Viruse

    Comparative Proteomic Profiling of Methicillin‐Susceptible and Resistant Staphylococcus aureus

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    Purpose Staphylococcus aureus is a highly successful human pathogen responsible for wide range of infections. In this study, we provide insights into the virulence, pathogenicity, and antimicrobial resistance determinants of methicillin susceptible and methicillin resistant Staphylococcus aureus (MSSA; MRSA) recovered from non‐healthcare environments. Experiment design Three environmental MSSA and three environmental MRSA were selected for proteomic profiling using iTRAQ MS/MS. Gene Ontology (GO) Annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway Annotation were applied to interpret the functions of the proteins detected. Results 792 proteins were identified in MSSA and MRSA. Comparative analysis of MRSA and MSSA revealed that 8 of out 792 proteins were up‐regulated and 156 were down‐regulated. Proteins that had differences in abundance were predominantly involved in catalytic and binding activity. Among 164 differently abundant proteins, 29 were involved in pathogenesis, antimicrobial resistance, stress response, mismatch repair and cell wall synthesis. Twenty‐two proteins associated with pathogenicity, including spa, sbi, clfA and dlt were up‐regulated in MRSA. Moreover, the up‐regulated pathogenic protein entC2 in MSSA was determined to be a super antigen potentially capable of triggering toxic shock syndrome in the host. Conclusions Enhanced pathogenicity, antimicrobial resistance and stress response were observed in MRSA compared to MSSA

    Automatic classification of eutrophication of inland lakes from spacecraft data

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    The author has identified the following significant results. Spacecraft data and computer techniques can be used to rapidly map and store onto digital tapes watershed land use information. Software is now available by which this land use information can be rapidly and economically extracted from the tapes and related to coliform counts and other lake contaminants (e.g. phosphorus). These tools are basic elements for determining those land use factors and sources of nutrients that accelerate eutrophication in lakes and reservoirs
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