Task-phase-specific dynamics of basal forebrain neuronal ensembles.

Cortically projecting basal forebrain neurons play a critical role in learning and attention, and their degeneration accompanies age-related impairments in cognition. Despite the impressive anatomical and cell-type complexity of this system, currently available data suggest that basal forebrain neurons lack complexity in their response fields, with activity primarily reflecting only macro-level brain states such as sleep and wake, onset of relevant stimuli and/or reward obtainment. The current study examined the spiking activity of basal forebrain neuron populations across multiple phases of a selective attention task, addressing, in particular, the issue of complexity in ensemble firing patterns across time. Clustering techniques applied to the full population revealed a large number of distinct categories of task-phase-specific activity patterns. Unique population firing-rate vectors defined each task phase and most categories of task-phase-specific firing had counterparts with opposing firing patterns. An analogous set of task-phase-specific firing patterns was also observed in a population of posterior parietal cortex neurons. Thus, consistent with the known anatomical complexity, basal forebrain population dynamics are capable of differentially modulating their cortical targets according to the unique sets of environmental stimuli, motor requirements, and cognitive processes associated with different task phases

Splenic Artery Aneurysms

Splenic artery aneurysms (SAAs) are a rare arterial disease (1) and defined as a diameter of more than 50% of expected (0.9 - 1 cm) splenic artery diameter.  They account for 60-70% of visceral artery aneurysms making them the most common of this group (4).  They are often difficult to diagnose due to their vague or non-existing symptoms but present a high risk of rupture in certain patient groups making this a clinically important differential diagnosis. Â

The relationship of readiness factors to Jan. first grade reading achievement

Thesis (Ed.M.)--Boston Universit

Co- variation in soil biodiversity and biogeochemistry in northern and southern Victoria Land, Antarctica

Data from six sites in Victoria Land (72–77°S) investigating co-variation in soil communities (microbial and invertebrate) with biogeochemical properties showthe influence of soil properties on habitat suitability varied among local landscapes as well as across climate gradients. Species richness of metazoan invertebrates (Nematoda, Tardigrada and Rotifera) was similar to previous descriptions in this region, though identification of three cryptic nematode species of Eudorylaimus through DNA analysis contributed to the understanding of controls over habitat preferences for individual species. Denaturing Gradient Gel Electrophoresis profiles revealed unexpectedly high diversity of bacteria. Distribution of distinct bacterial communities was associated with specific sites in northern and southern Victoria Land, as was the distribution of nematode and tardigrade species. Variation in soil metazoan communities was related to differences in soil organic matter, while bacterial diversity and community structure were not strongly correlated with any single soil property. There were no apparent correlations between metazoan and bacterial diversity, suggesting that controls over distribution and habitat suitability are different for bacterial and metazoan communities. Our results imply that top-down controls over bacterial diversity mediated by their metazoan consumers are not significant determinants of bacterial community structure and biomass in these ecosystems

A Photometric Technique to Search for Be Stars in Open Clusters

We describe a technique to identify Be stars in open clusters using Stromgren b, y, and narrow-band Halpha photometry. We first identify the B-type stars of the cluster using a theoretical isochrone fit to the (b-y, y) color-magnitude diagram. The strongest Be stars are easily identified in a (b-y, y-Halpha) color-color diagram, but those with weaker Halpha emission (classified as possible Be star detections) may be confused with evolved or foreground stars. Here we present such photometry plus Halpha spectroscopy of members of the cluster NGC 3766 to demonstrate the accuracy of our technique. Statistical results on the relative numbers of Be and B-type stars in additional clusters will be presented in a future paper.Comment: 15 pages, 6 figures, 1 table. Accepted by Ap

Mortar Board: A Century of Scholars, Chosen for Leadership, United to Serve

Mortar Board National College Senior Honor Society has a unique place in the history of higher education and indeed in the history of the United States. Founded in 1918, with inaugural chapters at Cornell University, University of Michigan, The Ohio State University, and Swarthmore College, Mortar Board was the first national organization to honor senior college women. Before women had the right to vote in the United States, Mortar Board members were leading their society to prominence across the country. In a real sense, Mortar Board grew up with the US higher education system and grew in step with women’s emergence as recognized leaders nationally. As a result, the history of Mortar Board members and their accomplishments provides readers with a unique window into women’s issues on campuses during the twentieth century, the importance of college student organizations to the quality of student life, and the effect of world events on American college students. Accepting men into its ranks since 1975, Mortar Board has grown into a comprehensive national college senior honor society comprised of students who exemplify Mortar Board’s founding Ideals of scholarship, leadership, and service. In preparation for its centennial, volunteers poured over fifty thousand photos, memos, and files to prepare its first-ever history. The result is a beautifully accurate, sometimes humorous, and always enlightening portrayal of college life in the United States over the last one hundred years.https://docs.lib.purdue.edu/purduepress_previews/1012/thumbnail.jp