1,721,457 research outputs found
Studio dell’interazione dell’acido L,L-diamminopimelico e alcuni inibitori con la DAP epimrasi mediante metodi di docking molecolare
No full textOne port measurement procedure for two ports devices with different port connectors
No full textINRiM Technical Report n.8
Examples of indefinite globally framed f-structures on compact Lie groups
No full textWe extend to the semi-Riemannian context the well-known results obtained by Blair, Ludden and Yano on toroidal principal bundles endowed with a metric globally framed f-structure. In this way we obtain examples of compact indefinite S-manifolds. Then, we define an indefinite S-structure on the Lie
group U(2) with a Lorentz left-invariant metric and, applying our results,
we construct commutative diagrams involving semi-Riemannian submersions
and Hopf fibrations. We also prove that U(2) with such a structure is foliated by Reinhart lightlike hypersurfaces. Finally, we consider a normal indefinite globally framed f-structure on the Lie group U(4) pro-
ving that it projects on
U(4)/U(3) in a Sasakian structure isomorphic to the
standard Sasakian structure of S^
Curvature of a class of indefinite globally framed f-manifolds
No full textWe present a compared analysis of some properties of indefinite almost
S-manifolds and indefinite S-manifolds. We give some characterizations in
terms of the Levi-Civita connection and of the characteristic vector fields.
We study the sectional and \phi-sectional curvature of indefinite almost S-
manifolds and state an expression of the curvature tensor field for the inde-
finite S-space forms. We analyse the sectional curvature of indefinite S-
manifold in which the number of the spacelike characteristic vector fields
is equal to that of the timelike characteristic vector fields. Some examples
are also described
Lightlike hypersurfaces in indefinite S-manifolds
No full textIn a metric g.f.f-manifold we study lightlike hypersurfaces M tangent to the characteristic
vector fields, and owing to the presence of the f-structure, we determine some decompositions
of TM and of a chosen screen distribution obtaining two distributions invariant with respect
to the structure. We discuss the existence of a g.f.f -structure on a lightlike hypersurface and,
under suitable hypotheses, we obtain an indefinite S-structure on the leaves of an integrable
distribution. The existence of totally umbilical lightlike hypersurfaces of an indefinite S-space
form is also discussed. Finally, we explicitely describe a lightlike hypersurface of an indefinite
S-manifold
On the classification of Lorentzian Sasaki space forms
No full textSasaki manifolds admit a nowhere vanishing vector field and it is
always possible to consider a Lorentz metric on them. Then we are able to
obtain a classification result for compact Lorentz–Sasaki space forms
Note about characteristic lightlike hypersurfaces of indefinite globally framed f-manifolds
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
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