There is a classical result known as Baer's Lemma that states that an $R$-module $E$ is injective if it is injective for $R$. This means that if a map from a submodule of $R$, that is, from a left ideal $L$ of $R$ to $E$ can always be extended to $R$, then a map to $E$ from a submodule $A$ of any $R$-module $B$ can be extended to $B$; in other words, $E$ is injective. In this paper, we generalize this result to the category $q_{\omega }$ consisting of the representations of an infinite line quiver. This generalization of Baer's Lemma is useful in proving that torsion free covers exist for $q_{\omega }$.
A histochemical study using lectin methods was performed on myxosporean parasites from vastly different fish hosts from marine and fresh waters. Six biotinylated lectins were used (WGA, SBA, BS-I, Con-А, UEA-I and SNA). The binding paltem of Con-A and WGA revealed the presence of mannose and/or glucose, and N-acetyl-D-glucosamine respectively, in polar capsules and valves of most of the myxosporea assayed. Thus, chitin may be present in polar capsules and/or valves of myxosporean spores. The BS-I binding pattern showed the presence of a-!)-galactose and/or N-acetyl-D-galactosamine residues in polar capsules of Kudoa sp., Zschokkeìla mugilis Sitjà-Bobadilla et Alvarez-Pellitero, 1993 and Leplotheca sp., and in the valves of the latter. Scarce amounts of N-acetyl-D-galactosamine and/or α-D-galactose were demonstrated by SBA binding in Sphaerospora dicentrarchi Sitjà-Bobadilla et Alvarez-Pellitero 1992, Leplotheca sp. and Kudoa sp. valves, and in Leptotheca sp. polar capsules. The UEA-I staining indicated the absence ofa-L-fucose in all the myxosporea assayed except in Leptotheca sp. N-acety!neuraminic acid was detected with SNA in the polar capsules and sporoplasms of Polysporoptasma sparis Sitjà-Bobadilla et-Alvarez-Pellitero, 1995 and in the polar capsules and valves of Kudoa sp. These results indicate that, although Myxosporea may have conserved carbohydrate structures, some of them can show significantly different binding patterns, which may be useful in diagnostic and functional studies.
The domatic numbers of a graph $G$ and of its complement $\bar{G}$ were studied by J. E. Dunbar, T. W. Haynes and M. A. Henning. They suggested four open problems. We will solve the following ones: Characterize bipartite graphs $G$ having $d(G) = d(\bar{G})$. Further, we will present a partial solution to the problem: Is it true that if $G$ is a graph satisfying $d(G) = d(\bar{G})$, then $\gamma (G) = \gamma (\bar{G})$? Finally, we prove an existence theorem concerning the total domatic number of a graph and of its complement.
The effect of solid concentration and mixture velocity on the flow behaviour, pressure drops, and concentration distribution of coarse particle-water mixtures in horizontal, vertical, and inclined smooth stainless steel pipes of inner diameter D = 100 mm was experimentally investigated. Graded basalt pebbles were used as solid particles. The study revealed that the coarse-grained particle-water mixtures in the horizontal and inclined pipes were significantly stratified. The solid particles moved principally in a layer close to the pipe invert; however for higher and moderate flow velocities, particle saltation became the dominant mode of particle conveyance. Frictional pressure drops in the horizontal pipe were found to be markedly higher than in the vertical pipe, while the frictional pressure drops in the ascending pipe increased with inclination angle up to about 30°.
Gas exchanges and related leaf traits of three co-occurring species of genus Cypripedium (C. yunnanense Franch., C. guttatum SW., and C. flavum P.F. Hunt et Summerch.) were investigated in a scrubland at 3 460 m a.s.l. in the Hengduan Mountains. The considered species had similar photosynthetic responses to photosynthetic photon flux density (PPFD) and air temperature. The photosynthetic capacity (Pmax), carboxylation efficiency (CE), apparent quantum efficiency (AQE), PPFD-saturated rate of electron transport (Jmax), respiration rate (RD), and leaf nitrogen content per unit area (LNC) of C. guttatum were higher than those of C. yunnanense and C. flavum. The highest Pmax of C. guttatum was related to the highest LNC and the lowest ratio of intercellular CO2 concentration to atmospheric CO2 concentration (Ci/Ca). However, no significant differences in stomatal conductance (gs) and relative stomatal limitations (RSL) were observed among the three species. Hence biochemical limitation had a dominant role in
Pmax differences among the considered species. and S. B. Zhang ... [et al.].
Two of 98 native littleneck clams, Protothaca staminea Conrad, from Cooper’s Cove, Sooke Basin were infected with an eimeriorin coccidian parasite. Merogonic, gamontogonic and sporogonie development were observed in renal tubular epithelial cells. Sporulation of the oocysts occurred within the host. Mature oocysts were spherical mean 41 pm (range 30-44), and contained about 32 subspherical sporocysts (9 x 10 pm), each of which contained 4 sporozoites. Spherical 19 pm (18-20), cyst-like structures and smaller multinucleate bodies, some of which resembled sporocysts, were also seen.A review of the coccidian parasites of bivalves led to the erection of the new genus, Margolisiella (family Eimeriidae Minchin, 1903) to accommodate M. kabatai sp. n., the parasite in Protothaca staminea described herein. Four previously described monoxenous species (Pseudoklossia patellae Debaisieux, P. chitonis Debaisieux, P. tellinovum Buchanan and P. halintis Friedman, Gardner, Hedrick, Stephenson, Cawthom et Upton) were also transferred to the new genus. The 2 remaining possibly heteroxenous species (P. pelseneeri Léger and P. glomerata Léger et Duboscq) were retained in the genus Pseudoklossia Léger et Duboscq (family Aggregatidae Labbé, 1899).