Total systems intervention: A practical face to critical systems thinking

This is the first exposition of a new methodology (or perhaps meta-methodology) for systems practice known as Total Systems Intervention (TSI). Designed to overcome the weaknesses of hard, cybernetic, and soft systems approaches and build on their strengths, TSI represents a practical face of critical systems thinking. It advocates combining three building blocks-systems metaphors, system of systems methodologies, and individual systems methodologies—in an interactive manner which is deemed to be particularly powerful and fruitful. In this paper the philosophy, principles, and phases of the TSI methodology are set out and two very different examples of its use are provided.     

破火山口塌陷构造的物理模拟研究

用聚合硅胶模拟塑性岩浆、用干燥松散石英砂模拟脆性围岩和顶板层，研究了由岩浆房的萎缩下沉所引起的破火山口塌陷构造.模拟岩浆房的初始形状包括平顶圆柱体及剖面呈长方形、半圆形、等腰三角形的条状体。实验中，圆形岩浆房的下沉形成圈环形塌陷构造；长条状岩浆房的下沉形成线形塌陷构造．塌陷构造在平面上通常呈对称的圈环状或条带状分布，从里向外一般由中央凹陷带、逆断层带、侧绕斜坡带以及周边正断层带组成．塌陷构造在剖面上呈上宽下窄的漏斗状，其中所有的断层都呈上缓下陡的凸弧形．周边正断层与其内侧的逆断层在深部合并、向下延伸、并消失于岩浆房与围岩的接触带内．塌陷内拉伸正断层与压缩逆断层或褶皱的共生及其分布方式、断层面上缓下陡的凸弧形几何形态等是厘定该构造的重要标志．     

A 1000-year chironomid-based salinity reconstruction from varved sediments of Sugan Lake, Qaidam Basin, arid Northwest China, and its palaeoclimatic significance

A 1000-year high-resolution （-10 years） chironomid record from varved sediments of Sugan Lake, Qaidam Basin on the northern Tibetan Plateau, is presented. The chironomid assemblages are mainly composed of the relatively high-saline-water taxa Psectrocladius barbimanus-type and Orthocladius/ Cricotopus, and the relatively low-saline-water taxa Procladius and Psectrocladius sordidellus-type. Variations in the chironomid fauna and inferred salinities suggest that over the last millennium, the Sugan Lake catchment has alternated between contrasting climatic conditions, having a dry climate during the period 990-1550 AD, a relatively humid climate during the Little Ice Age （LIA） （1550-1840 AD）, and a dry climate again from 1840 AD onwards. At the decadal to centennial scale, a wet event around 1200-1230 AD, interrupting the generally arid period （990-1550 AD）, and a dry event around 1590-1700 AD, punctuating the generally humid period （1550-1840 AD）, are clearly documented. Trends in the chironomid-based salinity time series indicate a highly unstable climate during the LIA when salinity fluctuations were of greater magnitude and higher frequency. The effective moisture evolution in the Sugan Lake catchment during the last millennium reconstructed by chironomid analysis is in broad agreement with previous palaeo-moisture data derived from other sites in arid Northwest China （ANC）. The LIA, characterized by generally humid conditions over the westerly-dominated ANC was distinctly different from that in monsoonal China, implying an ＂out-of-phase＂ relationship between moisture evolution in these two regions during the past 1000 years.     

Capacitance steps and fusion pores of small and large-dense-core vesicles in nerve terminals

The vesicles that package neurotransmitters fall into two distinct classes, large dense-core vesicles (LDCVs) and small synaptic vesicles, the coexistence of which is widespread in nerve terminals. High resolution capacitance recording reveals unitary steps proportional to vesicle size. Measurements of capacitance steps during LDCV and secretory granule fusion in endocrine and immune cells have provided important insights into exocytosis; however, extending these measurements to small synaptic vesicles has proven difficult. Here we report single vesicle capacitance steps in posterior pituitary nerve terminals. These nerve terminals contain neuropeptide-laden LDCVs, as well as microvesicles. Microvesicles are similar to synaptic vesicles in size, morphology and molecular composition, but their contents are unknown. Capacitance steps of two characteristic sizes, corresponding with microvesicles and LDCVs, were detected in patches of nerve terminal membrane. Both types of vesicles fuse in response to depolarization-induced Ca(2+) entry. Both undergo a reversible fusion process commonly referred to as 'kiss-and-run', but only rarely. Fusion pores seen during microvesicle kiss-and-run have a conductance of 19 pS, 11 times smaller than LDCV fusion pores. Thus, LDCVs and microvesicles use structurally different intermediates during exocytosis.     

The genome sequence of Schizosaccharomyces pombe

We have sequenced and annotated the genome of fission yeast (Schizosaccharomyces pombe), which contains the smallest number of protein-coding genes yet recorded for a eukaryote: 4,824. The centromeres are between 35 and 110 kilobases (kb) and contain related repeats including a highly conserved 1.8-kb element. Regions upstream of genes are longer than in budding yeast (Saccharomyces cerevisiae), possibly reflecting more-extended control regions. Some 43% of the genes contain introns, of which there are 4,730. Fifty genes have significant similarity with human disease genes; half of these are cancer related. We identify highly conserved genes important for eukaryotic cell organization including those required for the cytoskeleton, compartmentation, cell-cycle control, proteolysis, protein phosphorylation and RNA splicing. These genes may have originated with the appearance of eukaryotic life. Few similarly conserved genes that are important for multicellular organization were identified, suggesting that the transition from prokaryotes to eukaryotes required more new genes than did the transition from unicellular to multicellular organization.     

Evidence for selective adsorption and polymerization of thel-optical isomers of amino acids relative to thed-optical isomers on the edge faces of kaolinite

Zusammenfassung Auf Kaolinitkristallen werden diel-optischen Isomeren der Aminosäuren vollständiger adsorbiert und schneller polymerisiert als died-optischen Isomeren.

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The research as supported by a post-doctoral fellowship awarded by the School of Forestry, Yale University, New Haven (Conn., USA). I thank Dr. G. E.Hutchinson (Yale University) for helpful coments, and Dr. G. W.Brindley (Pennsylvania State University) for technical suggestions.