The natural development of a graduate student.

Drawing on the developmental theories of Shirley and Piaget, the question is raised as to whether there is a place for stage theory in the development of the graduate student - a natural educational progression for each student, beginning at entrance to university and ending in his thirties. Such a progression of stages is outlined, roughly balanced again chronological age and academic degree and proposed as a matter of research interest. Practical aspects are noted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence of hepatocyte apoptosis in rat liver after the administration of carbon tetrachloride

In acute liver injury induced by the injection of CCl4, cell death has been attributed to the necrosis of hepatocytes in the centrilobular area. In the present study, we re-examined the hepatic injury evoked by CCl4 in rats and explored the possibility that apoptosis may also contribute to its pathogenesis. Apoptotic hepatocytes were identified and quantified by light and electron microscopy, the in situ immunohistochemical labeling of nuclear DNA fragmentation, flow cytometry, and DNA gel electrophoresis. We found that a substantial number of hepatocytes underwent apoptosis. Apoptotic changes were also observed in ballooned hepatocytes. Apoptotic hepatocytes increased in number at 3 hours and peaked at 6 hours after the CCl4 injection. Apoptotic bodies were sequestrated in the adjacent hepatocytes and sinusoidal cells. Double staining of the cells with immunostaining for phagocytes and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining for labeling of DNA fragmentation showed that the majority of apoptotic hepatocytes were phagocytosed by Kupffer cells and macrophages. The results indicated that apoptosis occurs in the ballooned and injured hepatocytes of the centrilobular area. What occurs after CCl4 administration may be important in reducing inflammation, shortening the course of acute hepatic injury, and preventing the development of fibrosis.     

The nuclear stethoscope: a simple device for generation of left ventricular volume curves

Initial evaluation has begun of a system for displaying left ventricular time-activity curves, relating the intraventricular content of radioactivity with the cardiac cycle as determined by the patient's electrocardiogram. Major problems include proper positioning of the detector, correction for background radioactivity outside the ventricle and calibration of the device to permit conversion of measurement of radioactivity to measurement of ventricular volumes.     

Ocular Effects of Exposure to 40, 75, and 95 GHz Millimeter Waves

The objective of this study was to develop a model of ocular damage induced by 40, 75, and 95 GHz continuous millimeter waves (MMW), thereby allowing assessment of the clinical course of ocular damage resulting from exposure to thermal damage-inducing MMW. This study also examined the dependence of ocular damage on incident power density. Pigmented rabbit eyes were exposed to 40, 75, and 95 GHz MMW from a spot-focus-type lens antenna. Slight ocular damage was observed 10 min after MMW exposure, including reduced cornea thickness and reduced transparency. Diffuse fluorescein staining around the pupillary area indicated corneal epithelial injury. Slit-lamp examination 1 day after MMW exposure revealed a round area of opacity, accompanied by fluorescence staining, in the central pupillary zone. Corneal edema, indicative of corneal stromal damage, peaked 1 day after MMW exposure, with thickness gradually subsiding to normal. Three days after exposure, ocular conditions had almost normalized, though corneal thickness was slightly greater than that before exposure. The 50% probability of ocular damage (DD₅₀) was in the order 40?>?95?≈?75 GHz at the same incident power densities.     

Near-Surface Wind-Induced Mixing in a Mine Lake

Wind sheltering can have a strong effect in small, sheltered water bodies; wind-induced mixing in the surface layer of a small mine lake has been investigated using field measurements. Wind speed was recorded at three locations and data suggested sheltering by topography and surface roughness changes with both fetch and the land–water transition. Wind sheltering effects in the near-surface waters were assessed using turbulent microstructure profiler measurements, providing an estimate of the sheltering distance consistent with the literature on “backward-facing” steps. A numerical simulation of the annual density stratification cycle was then performed, using the model DYRESM. Simulations indicated that inclusion of a sheltering algorithm based on the results of the field campaign significantly improved the model’s performance in capturing the surface mixed layer deepening associated with strong wind events.     

Fractal stacked monopole with very wide bandwidth

A parallel feed stacked fractal antenna using the square Sierpinski and diamond Sierpinski carpet is introduced. The design achieves a good input impedance match throughout the passband (1-20 GHz) but occasional slight mismatch occurs. Three different experimental results are shown and the measured gain of these antennas is generally >0 dBi. These antennas are suitable for applications in picocell environments for the operating bands of GSM, DECT and WLAN systems