341 research outputs found

    Spectroscopic study of unique line broadening and inversion in low-pressure microwave generated water plasmas

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    It was demonstrated that low pressure (~0.2 Torr) water vapor plasmas generated in a 10 mm inner diameter quartz tube with an Evenson microwave cavity show at least two features which are not explained by conventional plasma models. First, significant (> 0.25 nm) hydrogen Balmer_ line broadening, of constant width, up to 5 cm from the microwave coupler was recorded. Only hydrogen, and not oxygen, showed significant line broadening. This feature, observed previously in hydrogen-containing mixed gas plasmas generated with high voltage dc and rf discharges was explained by some researchers to result from acceleration of hydrogen ions near the cathode. This explanation cannot apply to the line broadening observed in the (electrodeless) microwave plasmas generated in this work, particularly at distances as great as 5 cm from the microwave coupler. Second, inversion of the line intensities of both the Lyman and Balmer series, again, at distances up to 5 cm from the coupler, were observed. The line inversion suggests the existence of a hitherto unknown source of pumping of the optical power in plasmas. Finally, it is notable that other aspects of the plasma including the OH* rotational temperature and low electron concentrations are quite typical of plasmas of this type.Comment: 27 pages, 7 figure

    Subventricular zone stem cells are heterogeneous with respect to their embryonic origins and neurogenic fates in the adult olfactory bulb

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    Wedetermined the embryonic origins of adult forebrain subventricular zone (SVZ) stem cells by Cre-lox fate mapping in transgenic mice. We found that all parts of the telencephalic neuroepithelium, including the medial ganglionic eminence and lateral ganglionic eminence (LGE) and the cerebral cortex, contribute multipotent, self-renewing stem cells to the adult SVZ. Descendants of the embryonic LGE and cortex settle in ventral and dorsal aspects of the dorsolateral SVZ, respectively. Both populations contribute new (5-bromo-2(')-deoxyuridine- labeled) tyrosine hydroxylase- and calretinin-positive interneurons to the adult olfactory bulb. However, calbindin-positive interneurons in the olfactory glomeruli were generated exclusively by LGE- derived stem cells. Thus, different SVZ stem cells have different embryonic origins, colonize different parts of the SVZ, and generate different neuronal progeny, suggesting that some aspects of embryonic patterning are preserved in the adult SVZ. This could have important implications for the design of endogenous stem cell-based therapies in the future

    On the recent Introduction of outboard engines along the Coromandal coast

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    Introduction of outboard engines along the Coromandal coast and Pondicherry were studied. A total number of 232 outboard engines have been introduced at 16 fish landing centres in the South Arcot District. The outboard engines are fitted exclusively to catamarans with a length range of 8-10 m operating mainly gill nets, Pannu valai and Mani valai and the encircling bag-net, Eda valai

    Approximation theory in up-algebras based on intuitionistic fuzzy sets

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    This paper discusses the upper and lower approximations of Atanassov intuitionistic fuzzy sets in crisp and fuzzy approximation spaces in which both constructive and axiomatic approaches are used. In the constructive approach, concepts of intuitionistic fuzzy sets are defined, properties of intuitionistic fuzzy approximation operators are examined. Different classes of intuitionistic fuzzy set algebras are obtained from different types of fuzzy relations. In the axiomatic approach, an operator-oriented characterization of intuitionistic fuzzy sets is proposed

    Euclidean Greedy Drawings of Trees

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    Greedy embedding (or drawing) is a simple and efficient strategy to route messages in wireless sensor networks. For each source-destination pair of nodes s, t in a greedy embedding there is always a neighbor u of s that is closer to t according to some distance metric. The existence of greedy embeddings in the Euclidean plane R^2 is known for certain graph classes such as 3-connected planar graphs. We completely characterize the trees that admit a greedy embedding in R^2. This answers a question by Angelini et al. (Graph Drawing 2009) and is a further step in characterizing the graphs that admit Euclidean greedy embeddings.Comment: Expanded version of a paper to appear in the 21st European Symposium on Algorithms (ESA 2013). 24 pages, 20 figure

    An instance of mass mortality in the Muttukadu farm near Madras during April 1983

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    An unusual mortality of fishes and other organisms was observed in the open site surrounding the farm at Mariculture Centre of CMFRI, Muttukadu.at 1983. During this season the prevailing high temperature and salinity and the enclosed nature of the water body, all resulted in an intense bloom of dinophytes. This led to oxygen depletion of the waters and then, very likely, of the mud. The regular operation of drag nets and gill nets has stirred up the mud and created large scale disturbance which, combined with the oxygen depletion, must have precipitated the crisis and led to the mortality of prawns and fishes

    LR characterization of chirotopes of finite planar families of pairwise disjoint convex bodies

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    We extend the classical LR characterization of chirotopes of finite planar families of points to chirotopes of finite planar families of pairwise disjoint convex bodies: a map \c{hi} on the set of 3-subsets of a finite set I is a chirotope of finite planar families of pairwise disjoint convex bodies if and only if for every 3-, 4-, and 5-subset J of I the restriction of \c{hi} to the set of 3-subsets of J is a chirotope of finite planar families of pairwise disjoint convex bodies. Our main tool is the polarity map, i.e., the map that assigns to a convex body the set of lines missing its interior, from which we derive the key notion of arrangements of double pseudolines, introduced for the first time in this paper.Comment: 100 pages, 73 figures; accepted manuscript versio

    Change in hematologic indices over time in pediatric inflammatory bowel disease treated with azathioprine

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    Azathioprine leads to changes in mean corpuscular volume (MCV) and white blood cell (WBC) indices reflecting efficacy or toxicity. Understanding the interactions between bone marrow stem cells and azathioprine could highlight abnormal response patterns as forerunners for hematologic malig-nancies. This study gives a statistical description of factors influencing the relationship between MCV and WBC in children with inflammatory bowel disease treated with azathioprine. We found that leukopenia preceded macro¬cytosis. Macrocytosis is therefore not a good predictor of leukopenia. Further studies will be necessary to determine the subgroup of patients at increased risk of malignancies based on bone marrow response
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