142 research outputs found
Discussion Paper No. 1: The Detroit Geographical Expedition
Illustrations, maps, 28 cmhttps://digitalcommons.usm.maine.edu/detroitgeographicalexpedition/1002/thumbnail.jp
A Report to the Parents of Detroit on Decentralization
https://digitalcommons.usm.maine.edu/detroitgeographicalexpedition/1000/thumbnail.jp
Protistan community patterns within the brine and halocline of deep hypersaline anoxic basins in the eastern Mediterranean Sea
Author Posting. © The Author(s), 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Extremophiles 13 (2009): 151-167, doi:10.1007/s00792-008-0206-2.Environmental factors restrict the distribution of microbial eukaryotes but the
exact boundaries for eukaryotic life are not known. Here we examine protistan
communities at the extremes of salinity and osmotic pressure, and report rich
assemblages inhabiting Bannock and Discovery, two deep-sea superhaline
anoxic basins in the Mediterranean. Using a rRNA-based approach, we detected
1538 protistan rRNA gene sequences from water samples with total salinity
ranging from 39 g/kg to 280 g/Kg, and obtained evidence that this DNA was
endogenous to the extreme habitats sampled. Statistical analyses indicate that
the discovered phylotypes represent only a fraction of species actually inhabiting
both the brine and the brine-seawater interface, with as much as 82% of the
actual richness missed by our survey. Jaccard indices (e.g., for a comparison of
community membership) suggest that the brine/interface protistan communities
are unique to Bannock and Discovery basins, and share little (0.8-2.8%) in
species composition with overlying waters with typical marine salinity and oxygen
tension. The protistan communities from the basins’ brine and brine/seawater
interface appear to be particularly enriched with dinoflagellates, ciliates and other
alveolates, as well as fungi, and are conspicuously poor in stramenopiles. The
uniqueness and diversity of brine and brine-interface protistan communities make
them promising targets for protistan discovery.This study was supported by grant grant STO414/2-4 of the Deutsche
Forschungsgemeinschaft, the EuroDEEP program of the European Science
Foundation under 06-EuroDEEP-FP-004 MIDDLE project and NSF-grant MCB-
034834
Підручник зі слов’янського фольклору в Канаді
Рецензія на підручник: Kononenko N. Slavic Folklore: a Handbook. - Westport (Connecticut); London: Greenwood Press, 2007. - 209 pp
Spatial theory and human behavior
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45971/1/10110_2005_Article_BF01952731.pd
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The sensitivity of the myelin sheath, particularly the Schwann cell-axolemmal junction, to lowered calcium levels in cultured sensory ganglia
Light and electron microscopic observations were made on myelinated cultures of sensory ganglia maintained for 2–12 days on media with low calcium (0.025–0.050m
M) or normal calcium (1.5–2.0m
M) levels. After 18 h at low calcium levels, lengthening of the node of Ranvier and apparent fluid accumulation between the axon and the myelin sheath were observed in the light microscope. Electron microscopic observations indicated that these changes began with an accumulation of fluid between the Schwann cell terminal loops in the paranodal region, shrinkage and stretching of the terminal loops, and eventual breaking of the junction between the loops and the axolemma. Accompanying these changes was substantial fluid accumulation in the periaxonal space along much of the internode. These changes were found to be slowly reversible upon return to media with normal calcium levels. These observations are discussed in relation to the known properties of various types of intercellular junctions and the physiological properties of the myelinated nerve fiber. It is suggested that the unique structural characteristics of the Schwann cell-axolemmal junction in the paranodal region may relate to the presumed functional requirements of saltatory conduction,
i.e., adhesiveness for the maintenance of myelin form and/or sealing of the periaxonal space from the general extracellular space, but without the establishment of low resistance channels between Schwann cell and axon
The logical foundations of mathematics
The Logical Foundations of Mathematics offers a study of the foundations of mathematics, stressing comparisons between and critical analyses of the major non-constructive foundational systems. The position of constructivism within the spectrum of foundational philosophies is discussed, along with the exact relationship between topos theory and set theory.Comprised of eight chapters, this book begins with an introduction to first-order logic. In particular, two complete systems of axioms and rules for the first-order predicate calculus are given, one for efficiency in proving metatheorems, an
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