Abstract-In wideband spectrum sensing, secondary or unlicensed users take signal measurements over a given wide spectrum band and attempt to determine subbands for which the spectrum is idle and thus available for use. Some recent approaches to finding such spectrum holes generally employ some form of edge detection or energy detection. We propose an algorithm for joint time-frequency wideband spectrum sensing based on applying a form of temporal spectrum sensing together with a recursive tree search. The algorithm is able to detect spectrum holes accurately even in the presence of bursting primary signals and primary signals whose power spectral densities have smooth band edges. Numerical results are presented which show the performance gain of the proposed algorithm over earlier approaches to wideband spectrum sensing.
IntroductionDiscordant lymphomas are rare entities characterized by the simultaneous presence of two distinct types of lymphomas in different anatomic sites. We describe a very rare case of simultaneous occurrence of splenic mantle cell lymphoma and marginal zone lymphoma involving the bone marrow and peripheral blood.Case presentationWe report the case of a 60-year-old asymptomatic Caucasian woman in whom discordant lymphomas were discovered when a slight lymphocytosis and a conspicuous splenomegaly were observed. The different morphological, immunophenotypical and immunohistochemical features found in the different pathologic samples obtained from peripheral blood, bone marrow and spleen sections made it possible to differentiate two types of non-Hodgkin B-cell lymphomas: a mantle cell lymphoma infiltrating the spleen and a marginal zone lymphoma involving both the bone marrow and peripheral blood. Since a similar IgH gene rearrangement was found both in the bone marrow and in the spleen, the hypothesis of a common origin, followed by a different clonal selection of the neoplastic lymphocytes may be taken into consideration.ConclusionOur case emphasizes the usefulness of investigating simultaneous specimens from different anatomic sites from the same patient and the relevant diagnostic role of splenectomy.
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