Observation of the stray field of thin film magnetic tips using electron holography

The stray field around thin film ferromagnetic tips employed for magnetic force microscopy has been revealed using electron holography. The experimental phase difference maps are in good agreement with simulations. Quantitative flux measurements of the leakage field are obtained

Thickness and dielectric constant determination of thin dielectric layers

We derive a method for the determination of the dielectric constant and thickness of a thin dielectric layer, deposited on top of a thick dielectric layer which is in turn present on a metal film. Reflection of p- and s-polarized light from the metal layer yields minima for certain angles of incidence where the light is absorbed by the metal. The thin dielectric layer causes shifts in the angles at which the minima occur, from which the thickness and dielectric constant can be obtained. The model is tested for 3.5 and 14 nm thick photoresist gratings

Two small-volume electrochemical cells for the measurement of surface enhanced Raman scattering

Two electrochemical cells, for performing surface enhanced Raman scattering (SERS), with submillilitre volumes are presented. One of the cells is especially developed for use in a Raman microspectrometer. The smallest cell uses only 80 mu l of sample. SER measurements are performed on 2*10-3 M adenine

Prevalence of Intestinal Parasites in Iowa Dogs A comparison between 1965-68 and 1988

The prevalence of common intestinal parasites of dogs was determined and compared for the years 1965-68 and 1988 to determine what change, if any, has occurred in the prevalence of parasitisms over the past 20 years. Feces from dogs admitted to the Veterinary Teaching Hospital during these 2 periods were evaluated as part of the routine physical examination procedure. A sugar centrifugation method was used

Radio supernovae, supernova remnants and HII regions in NGC 2146 observed with MERLIN and the VLA

We present a high-resolution 5-GHz radio continuum map of the starburst galaxy NGC 2146 made with MERLIN and the VLA, in a search of radio supernovae and supernova remnants expected to be already produced by the most massive stars in the starburst. At 5 GHz, about 20 point sources were detected earlier by Glendenning & Kronberg (1986) in the central 800 pc of NGC 2146. Our observations with higher sensitivity and resolution made with MERLIN and the VLA confirms the detection of 18 sources, and resolves 7 of them. Additional 1.6-GHz MERLIN observations disclose 9 sources coincident in position with those detected at 5 GHz, which allows us to derive their spectral indices. Only 3 sources have indices consistent with synchrotron emission from supernova remnants or radio supernovae, while the others have very steep inverted spectra. We suggest that the sources with positive spectral index are optically thick ultra-compact and/or ultra-dense HII regions with high electron densities and high emission measures (EM > 10^(7) cm^(-6) pc). Minimum energy requirements indicate that these regions may contain up to 1000 equivalent stars of type O6. When compared with M 82, the galaxy NGC 2146 lacks however a large number of supernova remnants. We suggest that NGC 2146 is experiencing a burst of star formation stronger than that in M 82, but being in a younger phase. We may, however, not exclude an alternative scenario in which strong free-free absorption at 1.6 GHz in foreground ionized gas with very high emission measures (EM > 10^(8) cm^(-6) pc) hides a certain number of supernova remnants, thus rendering for some sources the observed inverted spectra.Comment: 10 pages, including 2 figures. Accepted for publication in Astronomy and Astrophysic

Paragonimiasis In Iowa

The presence of the lung fluke, Paragonimus kelliocotti, was first recorded in the United States in a cat in 1894. It was first recognized in domesticated animals in Iowa in a dog from Blackhawk County in 1948. Subsequently, paragonimiasis has been diagnosed in dogs from Polk and Dallas counties. An additional case was found in a dog from an unrecorded county. Also, one cat from Story County has been found to harbor P. kellicotti