Multi-model ensembles in climate science: Mathematical structures and expert judgements

Projections of future climate change cannot rely on a single model. It has become common to rely on multiple simulations generated by Multi-Model Ensembles (MMEs), especially to quantify the uncertainty about what would constitute an adequate model structure. But, as Parker points out (2018), one of the remaining philosophically interesting questions is: “How can ensemble studies be designed so that they probe uncertainty in desired ways?” This paper offers two interpretations of what General Circulation Models (GCMs) are and how MMEs made of GCMs should be designed. In the first interpretation, models are combinations of modules and parameterisations; an MME is obtained by “plugging and playing” with interchangeable modules and parameterisations. In the second interpretation, models are aggregations of expert judgements that result from a history of epistemic decisions made by scientists about the choice of representations; an MME is a sampling of expert judgements from modelling teams. We argue that, while the two interpretations involve distinct domains from philosophy of science and social epistemology, they both could be used in a complementary manner in order to explore ways of designing better MMEs.     

Mathematical formalisms in scientific practice: From denotation to model-based representation

The present paper argues that ‘mature mathematical formalisms’ play a central role in achieving representation via scientific models. A close discussion of two contemporary accounts of how mathematical models apply—the DDI account (according to which representation depends on the successful interplay of denotation, demonstration and interpretation) and the ‘matching model’ account—reveals shortcomings of each, which, it is argued, suggests that scientific representation may be ineliminably heterogeneous in character. In order to achieve a degree of unification that is compatible with successful representation, scientists often rely on the existence of a ‘mature mathematical formalism’, where the latter refers to a—mathematically formulated and physically interpreted—notational system of locally applicable rules that derive from (but need not be reducible to) fundamental theory. As mathematical formalisms undergo a process of elaboration, enrichment, and entrenchment, they come to embody theoretical, ontological, and methodological commitments and assumptions. Since these are enshrined in the formalism itself, they are no longer readily obvious to either the novice or the proficient user. At the same time as formalisms constrain what may be represented, they also function as inferential and interpretative resources.     

Differing morphology and ultrastructure of the male copulatory apparatus in species-groups of Anagrus Haliday (Hymenoptera: Mymaridae)

Male genitalia of 13 members of the mymarid wasp genus Anagrus have been studied: Anagrus (Anagrella) mymaricornis (Bakkendorf), Anagrus (Paranagrus) unilinearis Soyka, A. (Anagrus) ustulatus Haliday, A. (A.) erythroneurae Trjapitzin and Chiappini, A. (A.) atomus (Linnaeus), A. (A.) aegyptiacus Soyka, A. (A.) vilis Donev, A. (A.) sensillatus Viggiani and Jesu, A. (A.) breviphragma Soyka, A. (A.) incarnatus Haliday, A. (A.) obscurus Förster sensu Soyka, A. (A.) fennicus Soyka and A. (A.) avalae Soyka. Taxonomically significant differences between subgenera and the atomus and incarnatus species-groups are described. The functional significance of various features, and in particular, the arrangment of sensilla are discussed.     

Rediscovery of Gastrostyla setifera (Engelmann, 1862) Kent, 1882: morphology and divisional morphogenesis (Ciliophora,Hypotrichida)

The morphology and morphogenesis of the poorly known hypotrichous ciliate Gastrostyla setifera, isolated from a freshwater pond near Harbin, China, are described from both living and protargol silver-impregnated specimens. The Harbin population of this species is characterized thus: medium-sized freshwater Gastrostyla, 150-205 × 70-95 μm in vivo, ellipsoid in shape but somewhat narrowed posteriorly. Contractile vacuole located in left half of mid-body region. On average 48-56 (mean 52) adoral membranelles; 10 frontal and 9-11 ventral cirri; 23-26 left and 30-34 right marginal cirri; usually with four complete dorsal kineties and two dorsomarginal kineties; three caudal cirri present at posterior margin; invariably two macronuclear nodules and two micronuclei. Its morphogenesis reveals the following characteristics: (1) adoral zone of membranelles (AZM) in the opisthe arises from the new oral primordium while the proter inherits the entire parental structure; (2) 10 frontal, 9-11 ventral and five transverse cirri are derived from five frontoventral transverse cirral anlagen together with the undulating membrane anlage; (3) left and right marginal cirri are derived from new anlagen which originate within the old marginal rows; (4) the generation of the dorsal kineties is of the 'two-group-mode'; three left primary dorsal anlagen and two dorsomarginal anlagen appear as two groups in both dividers from which all dorsal kineties are derived (the fourth kinety is formed due to the fragmentation of the third anlage); (5) one caudal cirrus is formed at the ends of each of the first, second and fourth dorsal anlagen.     

A morphological study of the enteric valves of the Afrotropical Apicotermitinae (Isoptera: Termitidae)

Soil-feeding termites are dominant members of the soil fauna in lowland tropical rainforests. As ecosystem engineers, they have a profound effect on their environment, particularly through modification of the vast quantities of soil that they ingest. There is growing evidence that the processing of the soil in the gut is influenced by the enteric valve--an extremely well-developed feature in the hindgut of the Termitidae, consisting of six ridges, variously armed with spines, teeth and scales. Although this valve has been extensively used in morphological work, little is known of its function. Scanning electron microscopy has been used in this study to better understand the three-dimensional structure of the enteric valve in the Afrotropical Apicotermitinae, a group in which these valves are everted into the following chamber of the hindgut. This configuration lends itself to scanning electron microscopy in a way that it does not in other soil-feeders, since in those species the armature is obscured within the gut lumen. It seems plausible that this structure is instrumental in filtering material through the gut in such a way that the coarse, organic-poor portion of the soil is channeled fast through the centre, while directing the fine, organic-rich portion to the edges for lengthier digestion of recalcitrant plant material. Thus, the enteric valve would appear to be important for the termites to survive on this nutrient-poor but super-abundant food resource.     

Comparison of Anuropus branchiatus Beddard and A. bathypelagicus Menzies & Dow

Summary

The discovery of Serolis tropica sp. nov. in the shallow shelf zone of the Pacific of Panamá, just south of 9°N latitude, establishes the first occurrence of the Serolidae in tropical American waters. Since gravid females were found in cool as well as warm thermal seasons, it is assumed that this species is adapted to live under tropical conditions. Serolis yongei, known from the Great Barrier Reef, was collected at a depth of 200 m. It is not presently known if this species, like S. tropica, also inhabits the shallow shelf where warm-water conditions prevail.

Serolis tropica, a member of the North American ‘carinata’ group, is related to the ‘marplatensis’ group of South America. While it is argued that these two groups must have shared a common history, the remaining region of approximately 40° latitude between the northern and southern forms greatly complicates the relationship. Whether or not this gap is real or due to a lack of fine, inshore sampling can only be determined by further field work in this region.     

保险中的数学建模

保险已成为当今社会的时尚。本文以人们对寿险的需求为背景,运用数学建模分析方法,给出选择合适险种的判断公式,具有实际意义。     

关于高师数学教育专业深化改革的思考

本文从高师数学教育专业存在的问题出发,从教学内容、教学方法和教学手段等方面探讨了如何进行改革的问题。     

"更相减损术"不是求最大公因数的算法

人民教育出版社出版的普通高中课程标准实验教科书《数学③》(必修)指出《九章算术》中的“更相减损术”是求两个数的最大公约数的算法,其实“更相减损术”是将一个分数化简为既约分数的算法。     

垂直环空气液两相流流型的实验研究

针对国内外井涌理论中存在的问题，对空气－水、空气－泥浆两相流系统进行了实验研究．用垂直环空管流实验架、井眼数据测量与传输遥测系统，以及计算机实时数据采集系统，获取了大量实验数据．在此基础上，绘制了空气－水、空气－泥浆两相流的流型图，并利用回归分析的数学方法获取了空气－泥浆两相流泡状流向弹状流过渡的过渡区数学模型．