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Five species of sea skaters, genus Halobates Eschscholtz, are the only insects to have successfully colonized the open ocean. In addition, 36 species are found in sheltered coastal waters throughout tropical Indo-Pacific. The taxonomy of the genus is relatively well known, but reliable hypotheses about phylogenetic relationships are required if the biogeography and evolution of sea skaters is to be discussed in a meaningful way. This work presents the results of a study of new characters from the genital segments, especially those of the male phallus and the female gynatrial complex, and a reinterpretation for several other characters. In total 64 characters were scored for 26 species of Halobates , two species ofAsclepios and one species of Metrocoris. With Asclepios and Metrocoris species as outgroups, the character state sets were analysed cladistically using the computer program Hennig86. After critical evaluations of both characters and clades, a phylogeny for Halobates is presented and its taxonomic implications are discussed. A number of monophyletic species groups are delimited. One genus-level synonymy and three species-level synonymies are suggested. The evolution of Halobates is discussed in the light of the reconstructed phylogeny and present knowledge of the ecology and behaviour of sea skaters. A hypothesis of ecological evolution in halobatine water striders is proposed and tested.  相似文献   
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The effect of inert helium and argon gases on the tissue respiration has been studied on lymphocyte suspensions of white rats. It is shown that normoxic helium-oxygen mixture induces almost a two-fold increase of the O2 uptake by lymphocytes as compared with the control (air). No deviations in the value of the studied parameter are revealed in case of replacement of nitrogen from air by argon. Significance of the membrane structure in realization of effects of inert gases is under discussion.  相似文献   
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A total of 626 patients undergoing a prostaglandin-induced abortion, the majority in the second trimester, have been analysed for complications occurring during inpatient treatment. Of the last 155 consecutive patients 143 were critically assessed six to eight weeks after abortion for morbidity occurring during their early recovery period.Blood loss of 250 ml or more occurred in 68 patients, pyrexia in 34, pelvic infection in three, and readmission in 14 of the 626 patients studied, and a transfusion was required in eight.Bleeding after abortion stopped within six weeks in all 143 of the 155 consecutive patients assessed but three required readmission for uterine curettage. Menstruation was re-established within six weeks of abortion in 106 patients.The incidence of operative morbidity was similar to that reported for first trimester abortion and better than that in most reported series of second trimester abortions.  相似文献   
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