分类： 生物学 >> 动物学 提交时间： 2022-10-16 合作期刊: 《古脊椎动物学报》
摘要： The saurichthyiform fishes, characterized by a pointed rostrum and a streamlined long and slender body plan, ranked among the top predators of the ichthyofauna in the Early Mesozoic oceanic ecosystem. In a cosmopolitan pattern, these fishes rapidly radiated after the end-Permian mass extinction (EPME) and diversified morphologically and ecologically during the Middle Triassic. Thereafter, they seemingly showed a notable shrinkage from a global distribution to an occurrence basically restricted to the western Paleo-Tethys realm since the Late Triassic. Specifically, there is no saurichthyiform fossil record so far from the marine Late Triassic of South China (eastern Paleo-Tethys), where contrastingly they were highly diversified in stratigraphically older Lagersttten (Middle Triassic Panxian-Luoping and Xingyi biotas). Here we report the discovery of Saurichthys taotie sp. nov. from the Guanling biota of Guizhou and Yunnan provinces, southwestern China. This new species is a medium-sized Saurichthys featured by subtriangular subopercles ornamented with densely arranged vertical striae, faint ornamentation on the posterior part of the skull roof, and strong longitudinal ridges decorating the anterodorsal surface of the rostrum. By marking its own groups first occurrence in the Late Triassic of eastern Paleo-Tethyan province, Saurichthys taotie suggests that the saurichthyiform fishes were actually much more widespread than previously thought during that geological stage when they showed a considerable decline in the diversity. By still possessing some features previously only seen in its Early Triassic congeners elsewhere, Saurichthys taotie sheds new light on the evolutionary and paleobiogeographical history of saurichthyiform fishes.
分类： 管理学 >> 科学学与科技管理 分类： 图书馆学、情报学 >> 情报学 提交时间： 2022-10-16
摘要： 为促进科学内外对科研诚信外部规范相关制度的批判完善，基于科研诚信外部规范视域考察了国家科技计划项目抽检制度化实践的现实驱动与学理逻辑。其现实驱动主要是：①公共认知及科研组织模式演进背景下的全球科研诚信危机与科研诚信外部规范制度化趋势；②政府确保国家科技计划诚信、效率与本土效益的刚性需求；③过度依赖举报、舆论和社会道德奖惩系统的显著缺陷。其学理逻辑源自道德哲学、科学哲学、司法经济学、信息经济学及统计质量管理学，主要包括：①正视科研建制社会属性，完善道德自律的制度化规训；②提升惩罚技术品质，实现基于规则型惩罚的威慑机制；③缩短介入调查的委托-代理链条，提升科研诚信监督效率；④引入统计抽样+AQL技术策略，建立整体层面的科研质量宏观控制。研究结论和论证框架有利于深化各方对国家科技计划项目抽检及科研诚信外部规范的经验认知，并为管理决策、知识传播和理论更新迭代提供更简明、更有条理的分析框架与认知架构。
分类： 物理学 >> 地球物理学、天文学和天体物理学 分类： 物理学 >> 基本粒子与场物理学 提交时间： 2022-10-16
摘要：
It is reported that the Large High Altitude Air Shower Observatory (LHAASO) observed thousands 9 of very-high-energy photons up to ∼18 TeV from GRB 221009A. We study the survival rate of these 10 photons by considering the fact that they are absorbed by the extragalactic background light. By performing a set of 10 11 6 Monte-Carlo simulations, we explore the parameter space allowed by current 12 observations and find that the probability of predicting that LHAASO observes at least one photons 13 of 18 TeV from GRB 221009A within 2000 seconds is 4–5%. Hence, it is still possible for the standard 14 physics to interpret LHAASO’s observation in the energy range of several TeV. Our method can be 15 straightforwardly generalized to study more data sets of LHAASO and other experiments in the future.
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