Notes on Iowa Diatoms IV. : The Diatoms in a Northwest Iowa Fen

The physical features of a fen are discussed including chemical and physical analyses of the water. Diatom samples were taken during the summer of 1962 and a list of 48 species distributed among 20 genera was compiled. A series of photomicrographs of some of the species is presented. Ecological and floristic differences between cold and warm pools are discussed and a comparison with the diatom flora of the Cabin Creek Raised Bog in Indiana (published by C. W. Reimer) is made

Subliminal versus supraliminal stimuli activate neural responses in anterior cingulate cortex, fusiform gyrus and insula:a meta-analysis of fMRI studies

Background: Non-conscious neural activation may underlie various psychological functions in health and disorder. However, the neural substrates of non-conscious processing have not been entirely elucidated. Examining the differential effects of arousing stimuli that are consciously, versus unconsciously perceived will improve our knowledge of neural circuitry involved in non-conscious perception. Here we conduct preliminary analyses of neural activation in studies that have used both subliminal and supraliminal presentation of the same stimulus. Methods: We use Activation Likelihood Estimation (ALE) to examine functional Magnetic Resonance Imaging (fMRI) studies that uniquely present the same stimuli subliminally and supraliminally to healthy participants during functional magnetic resonance imaging (fMRI). We included a total of 193 foci from 9 studies representing subliminal stimulation and 315 foci from 10 studies representing supraliminal stimulation. Results: The anterior cingulate cortex is significantly activated during both subliminal and supraliminal stimulus presentation. Subliminal stimuli are linked to significantly increased activation in the right fusiform gyrus and right insula. Supraliminal stimuli show significantly increased activation in the left rostral anterior cingulate. Conclusions: Non-conscious processing of arousing stimuli may involve primary visual areas and may also recruit the insula, a brain area involved in eventual interoceptive awareness. The anterior cingulate is perhaps a key brain region for the integration of conscious and non-conscious processing. These preliminary data provide candidate brain regions for further study in to the neural correlates of conscious experience

Proverb interpretation in fluent aphasia and Alzheimer's disease: Implications beyond abstract thinking

This study compared proverb processing across three groups, i.e. patients with fluent aphasia (APH), patients with Alzheimer's Disease (AD), and normal control subjects (NC). Proverb stimuli were used to examine the effects of group membership and proverb familiarity in two presentation formats (i.e. spontaneous versus multiple-choice) on performance. The sensitivity of cognitive measures as predictors of ability to interpret proverbs was also investigated. In relation to NC subjects, patients with fluent APH exhibited significant difficulty formulating responses for familiar and unfamiliar spontaneous proverbs, whereas patients with AD demonstrated lower performance only on the unfamiliar proverbs. On the multiple-choice paradigm, however, patients with APH exhibited minimal difficulty. Conversely, the patients with AD manifested significant problems selecting the correct abstract response for familiar proverbs. With regard to predictors, language was relevant to familiar proverb interpretations and to proverbs presented in the spontaneous format. Cognition was a sensitive predictor for unfamiliar proverb interpretations and to the multiple-choice format. Deficits on the proverb tasks are discussed with reference to the potential breakdown of underlying linguistic and cognitive processes. The present data support the diagnostic value of proverbs in elucidating brain- behaviour relationships

AN EVALUATION OF THE SUBSTITUTION OF ZIRCALOY FOR STAINLESS STEEL IN N.S. SAVANNAH FUEL-ELEMENT CONTAINERS. Summary Report

The possibility of reducing fuel-cycle costs for the N.S. SAVANNAH by replacing the stainless steel fuelelement containers in the permanent reactor core structure by similar containers of a zirconium alloy was investigated. These containers, although not integral parts of the fuel-bearing components, are located within the active core and divide the core into 32 separate channels into which the fuel elements are placed. Areas of investigation included reactor physics, fuel-cycle economics, materials compatibility, structural design, and reactor hazards. A summary of the method of analysis and results is given for each area ot investigation. Calculations indicated that the substitution of Zircaloy containers would increase core reactivity about 6% DELTA k and control- rod worth about 4% DELTA k. Fuel-cycle costs would be reduced about 26%. Zircaloy-4 appears to be compatible with the reactor system, except for some uncertainty with respect to fretting corrosion, which can be resolved only by tests. The substitution of cold-worked Zircaloy for stainless steel in the container assembly would necessitate only minor design modifications. Although this evaluation is strictly applicable only to the N.S. SAVANNAH reactor, the results demonstrate the feasibility and advantages of using zirconium alloys for in-core capital-cost components. (auth

Place preference induced by nucleus accumbens amphetamine is impaired by local blockade of Group II metabotropic glutamate receptors in rats

BACKGROUND: The nucleus accumbens (NAc) plays a critical role in amphetamine-produced conditioned place preference (CPP). In previous studies, NAc basal and amphetamine-produced DA transmission was altered by Group II mGluR agents. We tested whether NAc amphetamine CPP depends on Group II mGluR transmission. RESULTS: NAc injections (0.5 μl/side) of the Group II mGluR antagonist (2 S)- a-ethylglutamic acid (EGLU: 0.01–0.8 μg but not 0.001 μg) impaired CPP. The drug did not block the acute locomotor effect of amphetamine. CONCLUSION: Results suggest that Group II mGluRs may be necessary for the establishment of NAc amphetamine-produced CPP. These receptors may also mediate other forms of reward-related learning dependent on this structure

Purification of urease by affinity chromatography. II. Further studies on matrix characteristics, ligand specificity, and adsorbent capacity

The synthesis of alternative adsorbents and their attempted use for the purification of urease from jack bean extracts and from several strains of Proteus morganii by affinity chromatography is described. The nature of the ligand and the length of the side chain joining the ligand to the agarose backbone of the matrix were critical factors in determining the suitability of these adsorbents for urease purification. Adsorbent capacities continued to be the only factor limiting the purification of urease by this method from any of the sources so far used. </jats:p