Kinetochore alignment within the metaphase plate is regulated by centromere stiffness and microtubule depolymerases

During mitosis in most eukaryotic cells, chromosomes align and form a metaphase plate halfway between the spindle poles, about which they exhibit oscillatory movement. These movements are accompanied by changes in the distance between sister kinetochores, commonly referred to as breathing. We developed a live cell imaging assay combined with computational image analysis to quantify the properties and dynamics of sister kinetochores in three dimensions. We show that baseline oscillation and breathing speeds in late prometaphase and metaphase are set by microtubule depolymerases, whereas oscillation and breathing periods depend on the stiffness of the mechanical linkage between sisters. Metaphase plates become thinner as cells progress toward anaphase as a result of reduced oscillation speed at a relatively constant oscillation period. The progressive slowdown of oscillation speed and its coupling to plate thickness depend nonlinearly on the stiffness of the mechanical linkage between sisters. We propose that metaphase plate formation and thinning require tight control of the state of the mechanical linkage between sisters mediated by centromeric chromatin and cohesion

MOLECULAR STRUCTURE AND EXCITON DYNAMICS IN ORGANIC CONJUGATED POLYMERS

Intermolecular electronic interactions, dipole coupling and orbital overlap, caused by π-π stacking in organic conjugated polymers lead to unique structures and properties that can be harnessed for optoelectronic applications. These interactions define structure-function relationships in amorphous and aggregated forms of polymers in the solid state and determine their efficiencies and functionality in electronic devices, from transistors to solar cells. Organic polymer electronic device performance depends critically upon electronic coupling between monomer units --mediated by conformation and packing characteristics -- that dictates electronic properties like conductivity and capacitance as well as electronic processes, such as charge carrier generation and transport. This dissertation demonstrates how electronic processes in conjugated polymers are mediated by subtle inter- and intra-chain electronic interactions imparted by the conformational degrees of freedom within their solid state structure and how this effects device performance. To initiate this investigation into structure-function relationships, an examination of nanoparticles representing two limiting aggregation states of the conjugated polymer poly(3-hexylthiophene) (P3HT) was conducted. These aggregates are defined by their predominate form of electronic coupling, inter- or intrachain, called H- and J-aggregates respectively. H- or J-aggregates of P3HT were embedded in an insulating matrix and time-resolved fluorescence intensity modulation spectroscopy was utilized to uncover the existence of efficient singlet-triplet quenching in J aggregates not present in H-aggregates. These studies were extended by examining P3HT H-and J-aggregates under applied electric fields in capacitor type devices using multiple time-resolved and steady-state spectroscopic techniques. These experiments reveal electronic couplings in J aggregates that shift excited state population towards a majority composed of long lived, quenchable, isolated singlet excitations. The structure of J aggregates which leads to isolated excitations, and the role which inter-chain contact sites play in triplet formation from these singlet excitations is revealed. New structure-function relationships were uncovered in poly (3-alkyl-thienylenevinylene) (P3ATV) derivatives using resonance Raman and photocurrent spectroscopies. Time-dependent spectroscopic theory was used to interpret experimental Raman and absorption spectra that revealed the presence of structural polymorphs. These polymorphs provide an explanation of the spectroscopic evidence without presumption of a deactivating dark state in this unusually non-fluorescence material. Photovoltaic devices constructed from blends of poly (2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) and PCBM blends were examined using Raman and photocurrent imaging techniques. These techniques were used to identify different packing states in blended thin films and correlate photocurrent production with local order. Intensity modulated spectroscopic techniques (IMPS) were then used to locate regions of non-geminate charge recombination at interfaces between amorphous and crystalline regions in working devices. Next, P3HT/PCBM OPV devices were exposed to ionizing radiation in a vacuum chamber. These devices were characterized before and after exposure, using standardized solar cell tests, Raman imaging, wide-field IMPS, and IMVS spectroscopies. An analysis of the spectroscopic data determined that the donor polymer is highly resistant to radiation damage, and that the degradation of device performance is due to an effect (cross-linking or degradation) within aggregates of the acceptor. This dissertation concludes with an interpretation of the significance of the findings contained herein to organic electronics, followed by a brief outlook for future work in these fields. Potential theories to describe and predict molecular interactions for organic polymers in the solid state based upon their structure are discussed here. This section also covers applications to device and material design features, from molecular considerations to engineered architectures

Modes of production, metabolism and resilience: toward a framework for the analysis of complex social-ecological systems

The field of environmental sociology has undergone drastic change in recent decades, in context of a broader reconfiguration of the terrain of sociological theory and practice. Systems-based approaches to the study of human society, located at the interface between the natural and social sciences have since yielded to a fragmentary body of theory and practice. Subsequent developments such as the emergence of actor network theory, linguistic constructivism and epistemic relativism, have sought not only to question the status of scientific discourse as immutable authority, but also the legitimacies of positivism and macro-theoretical modeling as tenable research programs. This thesis suggests that much of this critique is misdirected, informed as it is by false dichotomies of theory and method which empahsise the separatism of the social, and the difficulty of normative analysis. Over the past twenty years, sociologists have begun to re-engage with systemic theory, albeit with a plethora of new anti-reductionist informants rooted in epistemologies of emergentism, complexity and critical realism. Parallel developments in Marxian ecological thought and human ecology offer further conceptual complementarities and points of dialogue, with which to develop new methodologies for the study of human collectives as ‗social-ecological systems‘. The objectives of this work are thus twofold; (1) to advance an alternative basis for theory and practice in environmental sociology, drawing upon the informants of complexity theory, resilience-based human ecology, and Marx‘s concepts of mode of production and metabolic rift; (2) to contribute to this largely theoretical body of knowledge, by operationalising the preceding informants within a specific case study; that of communal farming, or the 'rundale system‘, in nineteenth century Ireland. The ecological dynamics of the rundale system are thus explored through the imposition of a range of quantitative, archival and comparative methods, as an exercise in the explanatory capacities of the investigative framework developed throughout this work. This methodology rejects existing explanatory models which emphasise the role of 'prime movers‘ in the generation of differential ecological outcomes, toward an account which emphasises both macro-structural complexity, and the augmentation of adaptive capacity from below

Foundations of Economic Science

The book presents a new paradigm of economic science as a science of exchange. It introduces a new analytical tool called consistency analysis to unify the entire body of economic theory, covering micro, macro, trade, money, development and demography. It uses a new wider and deeper concept of consistent choice to overcome the limits of rational choice. It incorporates entrepreneurship and transaction costs in a theory of intermediation, and stands on institutional rules to provide predictable regularity of social action of exchange. It shows transfer of value as the necessary function of money under indirect trade, and explains the equilibrium relation between output and money

Foundations of Economic Science

The book presents a new paradigm of economic science as a science of exchange. It introduces a new analytical tool called consistency analysis to unify the entire body of economic theory, covering micro, macro, trade, money, development and demography. It uses a new wider and deeper concept of consistent choice to overcome the limits of rational choice. It incorporates entrepreneurship and transaction costs in a theory of intermediation, and stands on institutional rules to provide predictable regularity of social action of exchange. It shows transfer of value as the necessary function of money under indirect trade, and explains the equilibrium relation between output and money

Energy: A continuing bibliography with indexes, issue 32

This bibliography lists 1316 reports, articles, and other documents introduced into the NASA scientific and technical information system from October 1, 1981 through December 31, 1981

Society, ritual and symbolism in Umeda village (West Sepik District, New Guinea)

This thesis concerns the people of Umeda village, one of the four villages which make up the Waina-Sowanda Census district of the West Sepik district of New Guinea. The thesis falls into three major parts. In the first part (Chapters 1 and 2) the major features of the social structure are outlined. The economy (based on Sago, hunting, and gardening) is described. The discussion of Social Structure looks at various 'levels' of organisation starting with the cost inclusive and working downwards. These levels are 1) the connubium, 2) the village, 3) Village societies 4) Bush associations 5) the hamlet 6) hamlet societies 7) clans and sub-clans, and 8) the household. The main theme of the discussion is the role of marriage alliance, set up through sister-exchanges between exogamous (patrilineal) clan-hamlets, as the 'lateral’ bonding element in the social structure. It is shown, for instance, that members of the society conceptualise its overall structure in terms of 'compatibilities’ set up by alliance relationships. These alliance relations, though actually shifting slightly with each generation are seen as permanent structural features. This is given symbolic expression in the Village- and Hamlet-moiety organisation. The opposition of kinship relations (within the clan-hamlet) and alliance relations (outside it) is postulated as the basis of a pervasive opposition between ‘central’ and 'lateral' -- an opposition which underlies the moiety organisation, and which is also of crucial importance in understanding the Symbolic System as found e.g. in Ritual. Later sections of Chapter 2 (viii - xi) discuss interpersonal relations in more detail. The problems posed by sorcery beliefs are discussed in relation to marriage and sexual relations generally. The concept of 'tadv' - relations (killing, eating, shooting, and copulating with the other} are discussed as the basic modality of ego-alter relations across sociological boundaries. Sorcery is the reciprocal of marriage. Chapter 3 takes up the second major theme of the Thesis. This chapter is devoted to linguistic symbolism, particularly in relation to the basic social and kinship roles. Three forms of linguistic symbolism (or 'lexical motivation’) are distinguished; 1) semantic motivation 2) morphological motivation 3) psychological motivation. Chapter 3 concerns itself only with the first two kinds, Phonological motivation in Umeda being explored in Appendix I as it poses problems which go beyond the purely Anthropological. It is shown that the Umeda vocabulary contains many implicit clues as to the symbolic system of the people. A system of analogies is demonstrated, using lexical evidence, between the structure of the body, the structure of botanical entities such as trees and the overall structure of the society. Once again the ‘central/lateral’ opposition is shown to be crucial, but this is further elaborated into a notion of ‘organic structure’ -- a structural model applicable both to biological and sociological organisms. Considerable attention is devoted to an analysis of Umeda tree symbolism: for instance, the fact that the Mother's Brother is (lexically) identified with the Sago Palm, the Ancestors with the Coconut palm and so on. Chapter 3 thus performs a 'bridging’ function between the first part of the thesis which is basically concerned with Sociological questions, and the second part which is concerned with Ritual Symbolism. Through a consideration of language, an understanding is gained both of the 'organic' metaphor at the heart of Umeda symbolism, and of the way in which this kind of metaphor meshes in with the details of the functioning of the social system, dominated by certain basic kinship roles. Chapter 4 is mainly descriptive. The Ida fertility rites, performed annually to increase the productivity of the sago palms are described in detail. A discussion of the actual ceremonies is preceded by an account of the many months of preparations for the ritual. It is argued that the ritual, and the need to accumulate supplies of food for its performance, imposes pattern and discipline on mundane economic activity. The ceremonies themselves consist of the appearance, over the course of a night and the subsequent two days, of a sequence of masked dancers (all male) representing various ritual roles. The most important roles are those of 1) cassowaries, 2) fish --- of which there are two kinds, the one red, the other black, 3) sago, 4) termites and 5) ipele bowmen, representing neophytes accompanied by preceptors. Chapter 5 takes the various ritual roles in order of their appearance and analyses their symbolic significance. A preliminary discussion is devoted to methodological issues. Subsequent sections discuss ritual roles under a number of rubrics e.g. the significance in practical or mythological terms of the animal or species represented, the significance of the constraints on actors taking certain roles, the significance of body-paint styles and mask styles, the (significances of various methods of dancing etc. All these ‘role attributes’ are set out in Tabular diagram-form (Table 5). The problem then becomes the analysis of the ritual process, seen as a sequence of transformations taking place in the attributes of successive ritual actors over the course of the total rite. It is demonstrated that the Ida ritual can be best understood as a concrete and dramatic representation of the overall process of bio-social regeneration. The cassowaries, who open the ritual, are shown transformed, and regenerated, as the (neophyte) bowmen, whose loosing off of magical arrows (ipele) is the culmination, and concluding, act of the ritual cycle. This finding is supported by detailed analyses of the transformations of mask-styles and body paint styles throughout the ritual. An extended account is given of Umeda colour symbolism. This leads, finally, to a discussion of the ritual representation of Time. It is argued that the ritual is a means of (symbolically) renewing Time. Certain contradictions inherent in the notion of temporality are specified, and the ritual is seen as a means of overcoming these contradictions within the cultural and symbolic milieu of Umeda. This chapter concludes the main part of the thesis. Two appendices deal I) with phonological motivation in Umeda – it is argued that articulatory features are employed expressively in the structure of Umeda lexical items. II) An appendix gives the complete Pul-tod Myth – a myth referred to at various points in the structure in the thesis, concerning the adventures of the ‘Oedipal’ hero, Pul-tod (Areca-man)