117,456 research outputs found
Carleson Measures and Logvinenko-Sereda sets on compact manifolds
No full textGiven a compact Riemannian manifold of dimension , we study the space of functions of generated by eigenfunctions of
eigenvalues less than associated to the Laplace-Beltrami operator on . On these spaces we give a characterization of the Carleson measures and the Logvinenko-Sereda sets
Carleson Measures and Logvinenko-Sereda sets on compact manifolds
No full textGiven a compact Riemannian manifold of dimension , we study the space of functions of generated by eigenfunctions of
eigenvalues less than associated to the Laplace-Beltrami operator on . On these spaces we give a characterization of the Carleson measures and the Logvinenko-Sereda sets
The Logvinenko-Sereda Theorem for the Fourier-Bessel transform
No full textInternational audienceThe aim of this paper is to establish an analogue of Logvinenko-Sereda's theorem for the Fourier-Bessel transform (or Hankel transform) \ff_\alpha of order . Roughly speaking, if we denote by the Paley-Wiener space of -functions with Fourier-Bessel transform supported in , then we show that the restriction map is essentially invertible on if and only if is sufficiently dense. Moreover, we give an estimate of the norm of the inverse map. As a side result we prove a Bernstein type inequality for the Fourier-Bessel transform
The Logvinenko-Sereda Theorem for the Fourier-Bessel transform
No full textInternational audienceThe aim of this paper is to establish an analogue of Logvinenko-Sereda's theorem for the Fourier-Bessel transform (or Hankel transform) \ff_\alpha of order . Roughly speaking, if we denote by the Paley-Wiener space of -functions with Fourier-Bessel transform supported in , then we show that the restriction map is essentially invertible on if and only if is sufficiently dense. Moreover, we give an estimate of the norm of the inverse map. As a side result we prove a Bernstein type inequality for the Fourier-Bessel transform
Effects of intercropping on growth, elemental composition and antioxidant activity of Artemisia scoparia and Raphanus sativus under lead supply
No full textArtemisia species and radish demonstrate intensive allelopathic properties and high ability to
hyperaccumulate heavy metals, but their interaction has not been studied up to date. In a pot experiment,
the relationship between wormwood (A. scoparia L.) and radish grown individually or intercropped,
without and with Pb(NO3)2 supply, was investigated. The intercropping had significant effects
in both species, as a consequence of metal allelopathy. Radish showed decrease of root biomass (1.75-
fold), Fe, Mn and Zn content (2-fold), Cu level (5.4-fold), and a 1.59-fold Pb increase in the leaves. In
wormwood, a 1.75-fold increase of root biomass, as well as a 7.2- and 2.8-fold increase of root and leaf
Fe content, respectively, were recorded. A. scoparia, the most Pb tolerant out of the 11 Artemisia
species investigated, accumulated 6.6 and 9.9 times more Pb in leaves and roots respectively, compared
to radish, under Pb supply which encouraged the growth of both plants. The intercropping under Pb
supply induced a three-fold decrease of radish root biomass and 7.8-fold decrease of Pb content.
Changes in plant antioxidant activity were recorded only under Pb supply and were not related to
radish-wormwood interaction: the leaf phenolics content and antioxidant activity displayed 1.4- and 2-
fold increases, respectively, in radish, and 1.4- and 1.6-fold decreases in wormwood. Synchronous
changes in elemental composition of wormwood and radish in intercropping conditions, without or
under Pb supply, suggest the significance of this phenomenon in plants interaction and arise high
prospects of A. scoparia utilization to tackle weeds and soil Pb pollution
Antioxidant properties and elemental composition of Withania somnifera L.
Get PDFWithania somnifera (L.) Dunal is popular in the traditional medicine of many areas of the world due to its high biological activity. Research was carried out in order to characterize the plants of this species in terms of antioxidant content and activity, as well as macro- and microelements concentration in leaves and roots plants grown along Crimea sea coast, which receive an intensive element transfer from the sea surface. The leaves of Withania somnifera showed higher levels of polyphenols, flavonoids and total antioxidant activity compared to roots (7.52 mg eq. GA g-1 d.w., 2.30 mg eq. quercetin g-1 d.w. and 38.2 mg eq. GA g-1 d.w. in leaves; 3.83 mg eq. GA g-1 d.w; 0.48 mg eq. quercetin g-1 d.w. and 10.8 mg eq. GA g-1 d.w. in the roots). Withanolides content in roots reached 0.62 %. The determination of 25 macro- and microelements revealed that Withania somnifera intensively accumulated Ca, K, Mg, P, B, I, Li, Mn, Mo, Si and Zn in leaves, whereas the concentration of V, Cr, Fe and Al in roots exceeded those recorded in leaves by 5.5, 5.86, 4.35 and 5.26 times respectively. The highest difference between leaves and roots concentration was detected for Li whose content in leaves was 10 times higher than in roots. Among other cultivated herbs (14 species belonging to Artemisia and Myrthus), Withania somnifera showed the highest levels of Li which makes it suppose this species is a good Li source for humans. Moreover, the leaves of W. somnifera contain high levels of iodine
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effect of Foliar Sodium Selenate and Nano Selenium Supply on Biochemical Characteristics, Essential Oil Accumulation and Mineral Composition of Artemisia annua L.
No full textSelenium (Se) biofortification of aromatic plants is a promising strategy to produce valuable
functional food with high biological activity and enhanced essential oil yield. The experiment
carried out in 2021 and 2022 on A. annua treated with sodium selenate or nano-Se sprayed on foliar
apparatus demonstrated a significant increase in photosynthetic pigments, pectin, waxes, macro- and
microelements and a decrease in malonic dialdehyde (MDA) accumulation. Contrary to literature
reports, neither selenate nor nano-Se showed a beneficial effect on essential oil accumulation; the oil
yield did not differ between the selenate treated and control plants but was halved by the nano-Se
application. Extremely high variations in the number of essential oil components, as well as in the
eucalyptol, artemisia ketone, camphor and germacrene D ratio in the 2021 and 2022 experiments
were recorded. The analysis of the 2016–2022 data for oil yield and composition in the control plants
revealed a direct correlation between the number of components and of solar flares, and a negative
correlation between oil yield and the percentage of spotless days. Both control plants and plants
fortified with selenium showed higher levels of germacrene D and lower levels of artemisia ketone in
2022, characterized by more remarkable solar activity compared to 2021. Nano-Se supply resulted in
the highest percentage of germacrene D accumulation. The results of the present research highlight
the importance of the solar activity effect on the essential oil yield and quality of aromatic plants
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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