991 resultados para 178-1100D
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Calcareous nannofossils, pollen, and spores were examined on samples from Ocean Drilling Program Leg 178 Site 1095 on the continental rise and Sites 1097, 1100, and 1103 on the outer continental shelf of the western Antarctic Peninsula. Stratigraphically useful specimens of calcareous nannofossils occur in Site 1095 sediments assigned to Zones CN15, CN13b, and CN11. Calcareous nannofossils are rare but occur throughout the sedimentary sequences from seismic Units S1 to S3 on the continental shelf. Most of the calcareous nannofossils in Units S1 and S2 are composed of Cretaceous specimens that have been recycled by glacial processes. The occurrence of Dictyococcites in samples within Unit S3 upper Miocene sediments without any reworked specimens suggests those sediments are deposited in an open-ocean environment. These results are consistent with those from foraminifer and radiolarian studies. Pollen and spores including Nothofagidites, the genus for fossil pollen referred to as Nothofagus, are also observed in Unit S3 sediments. The sparse occurrence of pollen and spores, however, makes it difficult to assess the nature of the Antarctic terrestrial vegetation.
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During Ocean Drilling Program Leg 178 we cored nine sites on the continental rise (Sites 1095, 1096, and 1101), continental shelf (Sites 1097, 1100, 1102, and 1103), and in an inner shelf basin, Palmer Deep (Sites 1098 and 1099), along the Pacific margin of the Antarctic Peninsula. Fossil diatoms are a key group that provides age constraint for these shelf site sediments to allow reconstruction of Antarctic Peninsula glacial history. This paper provides the systematic paleontology of diatoms applied in biostratigraphic and paleoceanographic studies and includes a total of 33 plates. Taxonomic confusion in previous reports, including biostratigraphically useful species such as Thalassiosira inura and Thalassiosira complicata, is discussed. These systematics and taxonomic discussions help to provide a reference for Neogene diatoms in the Southern Ocean.
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“History’s Children” stems from Anna Clark’s 2004 postdoctoral research into the ways in which Australian students connect with the past, and aims at bringing some classroom perspectives into the public debates about Australian history education. Although the title makes reference to the “History Wars”, there is little evidence of contestation, engagement, passion or intellectual excitement in Clark’s conclusions about what happens in history classrooms. Rather, Clark’s small focus groups with 182 high school students in 34 high schools around Australia indicate that “it got a bit dismal hearing student after student being so dismissive of Australian history” (p. 143). Apart from some enthusiasm for the study of Australians at war, a sort of resigned boredom seems to characterise what students have to say about learning Australian history, despite their acknowledgement that it is important to “know about” it.
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The significance of two interface arginine residues on the structural integrity of an obligatory dimeric enzyme thymidylate synthase (TS) from Lactobacillus casei was investigated by thermal and chemical denaturation. While the R178F mutant showed apparent stability to thermal denaturation by its decreased tendency to aggregate, the Tm of the R218K mutant was lowered by 5 degrees C. Equilibrium denaturation studies in guanidinium chloride (GdmCl) and urea indicate that in both the mutants, replacement of Arg residues results in more labile quaternary and tertiary interactions. Circular dichroism studies in aqueous buffer suggest that the protein interior in R218K may be less well-packed as compared to the wild type protein. The results emphasize that quaternary interactions may influence the stability of the tertiary fold of TS. The amino acid replacements also lead to notable alteration in the ability of the unfolding intermediate of TS to aggregate. The aggregated state of partially unfolded intermediate in the R178F mutant is stable over a narrower range of denaturant concentrations. In contrast, there is an exaggerated tendency on the part of R218K to aggregate in intermediate concentrations of the denaturant. The 3 A crystal structure of the R178F mutant reveals no major structural change as a consequence of amino acid substitution. The results may be rationalized in terms of mutational effects on both the folded and unfolded state of the protein. Site specific amino acid substitutions are useful in identifying specific regions of TS involved in association of non-native protein structures.
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利用在束实验产生具有β+/EC衰变性质核素176,178Ir,分析了在束实验条件下获得的γ-γ符合数据,识别出了176Os的4条新能级和13条新γ跃迁、178Os的5条新能级和14条新γ跃迁。籍助氦喷嘴快速带传输系统,进一步对176Ir的β+/EC衰变进行了测量,在确认在束测量新γ射线的同时建议了176Ir的一个低自旋同核异能态。通过两准粒子耦合的半经验计算,建议了176,178Ir基态及同核异能态的组态。
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利用152Sm(31P,5nγ)178Ir反应产生并研究了双奇核178Ir的高自旋态.实验中进行了178Ir核的在束 γ测量,包括γ射线的激发函数测量、X-γ和γ-γ符合测量.首次建立了双奇核178Ir基于πh9/2νi13/2和πh11/2νi13/2准粒子组态上的转动带能级纲图.发现在低自旋区,两个转动带能级均出现旋称反转.对此核区半退耦带的旋称反转作了简要的分析和讨论.
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The gamma rays following the beta(+)/EC decay of Ir-176,Ir-178 nuclei have been investigated using in-beam gamma-ray experiment. In addition, with the aid of a helium-jet recoil fast tape transport system, the beta(+)/EC decay of Ir-176 was further studied, the new gamma rays were proved and a low-spin isomer was proposed in Ir-176. The isomeric state was analysized according to the systematics in neighboring nuclei.
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10 fotografías a color.
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Au f. 157, souscription rubriquée du 20 novembre 1384: "Explicit summa dictaminis magistri Petri de Vineis. Qui scripsit scribat, semper cum Domini vivat. Ffinito (sic) libro, referamus gratia Christo. Ffuit (sic) scriptum presens opus et completum, die qua computabatur vicesima mensis novembris, anno a Nativitate Domini M°CCC° octuagesimo quarto". Tout le ms. est de la même main.