1,145 research outputs found

    The Sommerfeld half-plane problem revisited, IV: Variations on a theme of Carlson and Heins

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    A plane wave is incident upon an infinite set of equally spaced, semi-infinite parallel and staggered plates. The boundary conditions on the plates alternate between the Dirichlet and Neumann ones. This problem is formulated as a pair of coupled Wiener-Hopf integral equations and solved by a method proposed by A. E. Heins in 1950. For the case of specular reflection, that is, a single reflected plane wave, the magnitudes of the reflection coefficient and the transmission coefficients are determined.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50172/1/1670100307_ftp.pd

    The Reproductive Biology of Small Fishes and the Clutch Concept: Combining Macroscopic and Histological Approaches

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    Accurate estimates of reproductive parameters important in understanding life history evolution and conservation of small fishes are dependent upon careful assignment of ovarian phases. Proper assignment is based upon the stages of propagule (oocyte) development, oocyte maturation and the location of any clutch or portion thereof within the ovaries. Macroscopic inspection and assignment of ovarian developmental phases have often been used for small freshwater fishes. By contrast, histological methods for assignment of reproductive phases have been developed and are widely used for marine fishes, but they have rarely been used for small freshwater fishes. We review oocyte development, ovum maturation, and the ovarian cycling process using both macroscopic and histological approaches which incorporate the clutch concept. New terminology, including three actively spawning phases based on macroscopic appearance of the clutch (actively spawning-maturation, actively spawning-hydration, actively spawning-ovulation), is proposed. We assert that combining histological and macroscopic methodologies, shown to be complementary, will allow a more accurate and precise understanding of the reproductive biology of small fishes—especially freshwater fishes experiencing effects of habitat change and loss of habitat

    Applications of aerospace technology in industry, a technology transfer profile: Fire safety

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    The fire safety field is considered as being composed of three parts: an industry, a technology base, and a user base. An overview of the field is presented, including a perspective on the magnitude of the national fire safety problem. Selected NASA contributions to the technology of fire safety are considered. Communication mechanisms, particularly conferences and publications, used by NASA to alert the community to new developments in the fire safety field, are reviewed. Several examples of nonaerospace applications of NASA-generated fire safety technology are also presented. Issues associated with attempts to transfer this technology from the space program to other sectors of the American economy are outlined

    Applications of aerospace technology in industry, a technology transfer profile: Lubrication

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    Technology transfer in the lubrication field is discussed in terms of the movement of NASA-generated lubrication technology into the private sector as affected by evolving industrial requirements. An overview of the field is presented, and NASA technical contributions to lubrication technology are described. Specific examples in which these technologies have been used in the private sector are summarized

    Coulomb charging energy for arbitrary tunneling strength

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    The Coulomb energy of a small metallic island coupled to an electrode by a tunnel junction is investigated. We employ Monte Carlo simulations to determine the effective charging energy for arbitrary tunneling strength. For small tunneling conductance, the data agree with analytical results based on a perturbative treatment of electron tunneling, while for very strong tunneling recent semiclassical results for large conductance are approached. The data allow for an identification of the range of validity of various analytical predictions.Comment: 4 pages REVTeX, incl 3 figures, to appear in Europhys.Let

    Asymptotic behaviour of multiple scattering on infinite number of parallel demi-planes

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    The exact solution for the scattering of electromagnetic waves on an infinite number of parallel demi-planes has been obtained by J.F. Carlson and A.E. Heins in 1947 using the Wiener-Hopf method. We analyze their solution in the semiclassical limit of small wavelength and find the asymptotic behaviour of the reflection and transmission coefficients. The results are compared with the ones obtained within the Kirchhoff approximation

    Impact of Genetic Polymorphisms on the Smoking-related Risk of Periodontal Disease: the Population-based Study SHIP

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    Periodontitis is a bacterial inflammatory disease leading to attachment loss with the consequence of tooth loss. There exists a multifactorial risk pattern including bacterial challenge, smoking, age, sex, diabetes, socio-economic and genetic factors. Smoking has the highest impact on the course of the disease modulated by all the other factors. Here, we report the relationship between smoking and the polymorphisms of genetic polymorphisms inflicted in the pathogenesis

    Implications of a newly discovered DR5 specific antagonistic peptide for neurodegenerative disorders

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    Most neurodegenerative disorders are the result of inflammation and neuronal cell death. Although many cytokines have been implied to be involved in the pathogenesis, recent studies have shown TRAIL to be responsible for neuronal apoptosis.TRAIL is best known for its ability to induce apoptosis in many cancer cells. Normally TRAIL is not present in the CNS. However, it is induced by ÎČ‐amyloid protein and up regulated on infected macrophages which can infiltrate the CNS. TRAIL is able to induce apoptosis via death receptors DR4 and DR5. DR5 is shown to be expressed on neuronal cells. The identification of an antagonistic peptide that specifically binds DR5 provides us with a useful investigative tool. Small peptides can bind their targets with high affinity and specificity.In addition, they are easily modified and further developed for clinical application. So the peptide R2C16 might even be used as a lead peptide for the development of therapeutic agents in neurodegenerative disorders

    Adverse health effects after breast cancer up to 14 years after diagnosis

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    BACKGROUND: The number of breast cancer survivors increases, but information about long-term adverse health effects in breast cancer survivors is sparse. We aimed to get an overview of the health effects for which survivors visit their general practitioner up to 14 years after diagnosis. METHODS: We retrieved data on 11,671 women diagnosed with breast cancer in 2000–2016 and 23,242 age and sex matched controls from the PSCCR-Breast Cancer, a database containing data about cancer diagnosis, treatment and primary healthcare. We built Cox regression models for 685 health effects, with time until the health effect as the outcome and survivor/control and cancer treatment as predictors. Models were built separately for four age groups (aged 18/44, 45/59, 60/74 and 75/89) and two follow-up periods (1/4 and 5/14 years after diagnosis). RESULTS: 229 health effects occurred statistically significantly more often in survivors than in controls (p < 0.05). Health effects varied by age, time since diagnosis and treatment, but coughing, respiratory and urinary infections, fatigue, sleep problems, osteoporosis and lymphedema were statistically significantly increased in breast cancer survivors. Osteoporosis and chest symptoms were associated with hormone therapy; respiratory and skin infections with chemotherapy and lymphedema and skin infections with axillary dissection. CONCLUSIONS: Breast cancer survivors may experience numerous adverse health effects up to 14 years after diagnosis. Insight in individual risks may assist healthcare professionals in managing patient expectations and improve monitoring, detection and treatment of adverse health effects
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