2,684 research outputs found

    Malaria Control by Aircraft Spraying of Paris Green With Special Reference to Wartime Experience in Egypt

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    The malaria problem at an operational aerodrome beside a lake in Egypt is stated, and the bionomics of the mosquito vector described. The chief control measure was the spraying of Paris Green from aircraft over the breeding places of the vector. In 1944, spraying was extended along the lake edge to the large native village nearby, where the bulk of the breeding occurred. A number of experiments to test the effectiveness of the spraying are recorded, and details given of the spraying experience and difficulties encountered in 1944. Two modifications to the aircraft, one being the introduction of a hand operated agitator in the dust hopper, the other simplifying the control of the dust outflow were introduced. The incidence of primary malaria at the aerodrome, reduced following spraying in 1943, fell still further in 1944, and in that year at the village, the incidence fell to about one third of that of the three proceeding years. The requirements for successful aircraft spraying are discussed in the light of past and present experience

    Conceptual design study of a 5 kilowatt solar dynamic Brayton power system using a dome Fresnel lens solar concentrator

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    The primary project objective was to generate a conceptual design for a nominal 5 kW solar dynamic space power system, which uses a unique, patented, transmittance-optimized, dome-shaped, point-focus Fresnel lens as the optical concentrator. Compared to reflective concentrators, the dome lens allows 200 times larger slope errors for the same image displacement. Additionally, the dome lens allows the energy receiver, the power conversion unit (PCU), and the heat rejection radiator to be independently optimized in configuration and orientation, since none of these elements causes any aperture blockage. Based on optical and thermal trade studies, a 6.6 m diameter lens with a focal length of 7.2 m was selected. This lens should provide 87 percent net optical efficienty at 800X geometric concentration ratio. The large lens is comprised of 24 gores, which compactly stow together during launch, and automatically deploy on orbit. The total mass of the microglass lens panels, the graphite/epoxy support structure, and miscellaneous hardware is about 1.2 kg per square meter of aperture. The key problem for the dome lens approach relates to the selection of a space-durable lens material. For the first time, all-glass Fresnel lens samples were successfully made by a sol-gel casting process

    Keeping Primary Care Providers Informed about Detecting Skin Cancer in Young Adults

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    Skin cancer is a common, life-threatening disease that affects anyone, regardless of age or skin color (American Cancer Society [ACS], 2020). The incidence of melanoma is on the rise for young adults, with an estimated 2,400 new cases for individuals aged 15 to 29 (ACS, 2020). Although skin cancer is highly preventable, clinical guidelines are inconsistent regarding skin cancer screening. The purpose of this evidence-based practice (EBP) project was to determine if the implementation of the INternet curriculum FOR Melanoma Early Detection (INFORMED) program would improve primary care providers’ (PCPs’) confidence about skin cancer and the number of completed and documented skin assessments for young adults. Three PCPs employed at a student health center in Northwest Indiana participated in the 12-week long EBP project. Providers were instructed to complete a demographic form, pre-survey, the INFORMED program, and a post-survey. A skin assessment policy was created which required PCPs to apply their knowledge and diagnostic skills in the primary care setting. Two major outcomes were evaluated: providers’ confidence about skin cancer and the completion and documentation of a skin assessment. Providers’ confidence levels were measured with a pre- and post-survey. A paired t-test was calculated to determine if providers’ confidence about skin cancer improved after they completed the INFORMED program. Statistical significance was achieved for distinguishing benign lesions from malignant lesions (t (2) = -5.000, p = 0.038). A chi-square test of independence was calculated to compare the number of skin assessments completed and documented in 2019 and 2020. No significant relationship was found. Overall, providers were satisfied with the INFORMED program and felt that the program was valuable for their clinical practice. Results of this project could be used to encourage widespread dissemination of the INFORMED program in larger primary care settings in the United States

    Data acquisition system for NASA LaRC impact dynamics research facility

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    A data system is designed to permit the simultaneous recording of 90 data channels on one 28 track magnetic tape recorder using a constant bandwidth FM multiplexing technique. Dynamic signals from transducers located in the test aircraft are amplified and fed to voltage controlled oscillators where they are converted to discrete FM signals. The signals from each group of five VCO's are fed to a mixer/distribution amplifier where they are combined into one composite signal and recorded, using direct recording techniques, on one magnetic tape recorder track. Millivolt signals from the recorders reproduce heads are amplified to one volt and then electronically switched to an FM demultiplexing system where appropriate frequency discrimination and signal filtering recover the original analog information

    Recent advances in N- and C-terminus cysteine protein bioconjugation

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    Advances in the site-specific chemical modification of proteins, also referred to as protein bioconjugation, have proved instrumental in revolutionary approaches to designing new protein-based therapeutics. Of the sites available for protein modification, cysteine residues or the termini of proteins have proved especially popular owing to their favorable properties for site-specific modification. Strategies that, therefore, specifically target cysteine at the termini offer a combination of these favorable properties of cysteine and termini bioconjugation. In this review, we discuss these strategies with a particular focus on those reported recently and provide our opinion on the future direction of the field

    Using Markov Chains for link prediction in adaptive web sites

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    The large number of Web pages on many Web sites has raised navigational problems. Markov chains have recently been used to model user navigational behavior on the World Wide Web (WWW). In this paper, we propose a method for constructing a Markov model of a Web site based on past visitor behavior. We use the Markov model to make link predictions that assist new users to navigate the Web site. An algorithm for transition probability matrix compression has been used to cluster Web pages with similar transition behaviors and compress the transition matrix to an optimal size for efficient probability calculation in link prediction. A maximal forward path method is used to further improve the efficiency of link prediction. Link prediction has been implemented in an online system called ONE (Online Navigation Explorer) to assist users' navigation in the adaptive Web site

    Variations in the spatial distribution of 11 Micron radiation from omicron Ceti

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    The spatial distribution of 11 micron radiation from omicron Ceti was observed at various phases of its light cycle using a stellar interferometer. Changes were seen which can be attributed to variation in the strength of thermal emission from circumstellar dust relative to the stellar continuum at 11 microns. These changes are shown to be correlated with the changes in luminosity of micron Ceti in such a way that dust grain emission at 11 microns was increased more than the continuum during the period of maximum luminosity. The degree of the change in dust grain emission implies that the maximum dust temperature is in the range of 500 K to 700 K during minimum stellar luminosity

    The brightness distribution of IRC +10216 at 11 microns

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    The brightness distribution of IRC +10216 at a wavelength of 11 microns was measured in detail using a spatial interferometer. This brightness distribution appears to have azimuthal symmetry; an upper limit of 1.1 may be set to the ellipticity at 11 microns if the object has a major axis oriented either along or perpendicular to the major axis of the optical image. The radial distribution shows both compact and extended emission. The extended component, which is due to thermal emission from circumstellar dust, contributes 91% of the total flux and has a 1/e diameter of 0.90 minutes. The tapered shape of this component is consistent with a l/r squared dust density dependence. The compact component is unresolved (less than 0.2 minutes in diameter) and represents emission from the central star seen through the circumstellar envelope
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