619 research outputs found

    Constituent Groups of Clifford Semigroups Arising from t-Closure

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    The t-class semigroup of an integral domain R, denoted S_t(R), is the semigroup of fractional t-ideals modulo its subsemigroup of nonzero principal ideals with the operation induced by ideal t-multiplication. We recently proved that if R is a Krull-type domain, then S_t(R) is a Clifford semigroup. This paper aims to describe the idempotents of S_t(R) and the structure of their associated groups. We extend and recover well-known results on class semigroups of valuation domains and Prufer domains of finite character.Comment: 13 pages. To appear in Journal of Algebr

    Condensed And Strongly Condensed Domains

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    This paper deals with the concepts of condensed and strongly condensed domains. By definition, an integral domain R is condensed (resp. strongly condensed) if each pair of ideals I and J of R, IJ = {ab/a is an element of I, b is an element of J} (resp. IJ = aJ for some a is an element of I or IJ = Ib for some b is an element of J). More precisely,we investigate the ideal theory of condensed and strongly condensed domains in Noetherian-like settings, especially Mori and strong Mori domains and the transfer of these concepts to pullbacks

    Some larval morphological characteristics of Camelostrongylus mentulatus and Nematodirus spathiger

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    Monitoring of gastrointestinal nematode parasites in ruminants (domestic and wild) is often based on fecal examination techniques, looking for excreted eggs and larval forms using morphological keys. These, are more available in domestic ruminants, in which helminths are widely studied, than in wild ruminants.  This study tried to provide certain morphological elements that will help to recognize the L3 larvae of Camelostrongylus mentulatus and Nematodirus spathiger that could parasite either domestic or wild ruminants. For that, we resorted first to the culture of L3 larvae from fecal samples taken from African antelopes, and second by the microscopic characterization of each isolated larval morphological pattern previously identified by sequencing of its internal transcribed spacer (ITS-2) regions of the ribosomal DNA. The results of different microscopic captured images showed that Camelostrongylus mentulatus larva is 16 intestinal cells that measuring approximately 820 µm length, ‎≈ 25 µm wide, and ‎≈ 47 µm for its sheath tail extension and by this be closer to Teladorsagia circumcincta characteristics.  For Nematodirus spathiger, it possesses 8 gut cells and measuring about 1020 µm long, ‎≈ 25 µm wide, and‎ ≈ 143 µm for its sheath tail extension with specific tail appendages. Have done this, we were able to get some clarifications on the morphology of the studied larvae, and we believe thus that this study will contribute to the establishment of morphological identification keys especially for parasitic nematodes of wild ruminants
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