4,357 research outputs found

    Review of periodical articles

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    [First Paragraph] There is only one true city, wrote St Augustine, and it is not of this world. The pessimistic Christian response to the fall of Rome in AD 410, epitomized in Augustine's City of God, affected the development of the later medieval city to a degree which has yet, even now, to be fully appreciated. In the Christian city of the Middle Ages the divinity was normally confined to the sanctuaries of his churches, whose topographical prominence and harmonious proportions made manifest an otherwise hidden spiritual order. Outside the cloister gates, disorder reigned: a general lack of planning revealed the meaninglessness of the outward, secular life. This dichotomy between an inner world of spirit and a public world of transient matter was embodied in the recurrent tensions between spiritual and secular space which ran as a motif throughout the history of medieval towns. Modern studies which have emphasized (not, of course, without reason) the secular political and economic power of ecclesiastical institutions in the medieval city have perhaps distracted attention unduly from the real differences of ethos which, within the town, distinguished religious space from that of the surrounding lay world

    Review of periodical articles

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    One of the attractions of medieval urban history is the fact that major conceptual problems in the field continue to be debated. In a stimulating review article by J.H. Mundy, ’Philip Jones and the medieval Italian city-state‘, J. of European Economic History, 28 (1999), 185–200, one distinguished scholar is taxed for holding views now dismissed by some, but of which he is by no means a unique surviving representative. One of these views assumes a clear distinction between the antique city, supposedly a bureaucratic centre with limited economic functions, and the medieval city, as the home of industrious artisans and nascent capitalism. The image of the non-profit-making ancient town may be overly indebted to the nature of the literary sources and to the prevalent interests of classicists; but, although many would now agree that both the elements in the above equation need qualifying, a more focused comparison is presently lacking, and a fine book is still waiting to be written on the transition from the ancient world to the middle ages in urban history

    Electrons in the Earth's Outer Radiation Zone

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    Electrons in the earths outer radiation bel

    Fredkin Gates for Finite-valued Reversible and Conservative Logics

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    The basic principles and results of Conservative Logic introduced by Fredkin and Toffoli on the basis of a seminal paper of Landauer are extended to d-valued logics, with a special attention to three-valued logics. Different approaches to d-valued logics are examined in order to determine some possible universal sets of logic primitives. In particular, we consider the typical connectives of Lukasiewicz and Godel logics, as well as Chang's MV-algebras. As a result, some possible three-valued and d-valued universal gates are described which realize a functionally complete set of fundamental connectives.Comment: 57 pages, 10 figures, 16 tables, 2 diagram

    Distinct B cell profiles characterise healthy weight and obesity pre- and post-bariatric surgery

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    BACKGROUND/OBJECTIVES: Obesity-associated metabolic dysfunction and inflammation can be ameliorated by bariatric surgery. While obesity is also linked to impaired B cell activation, differentiation, and persistence in response to infection and vaccination little is known about post-operative immune B cell compartment and to what extent dysregulation in B cell pathways can be reversed. To bridge this gap in knowledge, we carried out in-depth evaluation of B cell composition in individuals with obesity prior to and following bariatric surgery compared to lean controls. SUBJECTS/METHODS: We recruited individuals with obesity (BMI at least 35 kg/m2) before bariatric surgery (n = 21) and followed them up 6 months post-operatively (n = 17). As controls we recruited age- and sex-matched lean (BMI < 25) individuals (n = 18). We carried out comprehensive immunophenotyping of peripheral blood B cells as well as interrogated their association with inflammatory and metabolic parameters. RESULTS: In obesity the balance of antigen-inexperienced and memory B cells in the peripheral blood is altered, with an expansion of naïve and a reduction in total memory B cells. 6 months following bariatric surgery this balance is restored. However, post-operative patients are uniquely characterised by an increase in B cell subsets associated with chronic inflammation - CD11c+CXCR5-IgD-CD27- double negative 2 (DN2) B cells and CD27+CD38++ plasmablasts. Correlations between B cells subsets, inflammatory and metabolic parameters were distinct in lean people and individuals with obesity pre- and post-bariatric surgery. CONCLUSIONS: Bariatric surgery patients display a unique B cell profile 6 months post-operatively; this bears minimal resemblance to that of pre-operative patients and only partially overlaps with that of lean controls. Post-operative differences in the B cell compartment compared to lean controls are detected despite global amelioration of inflammation and restoration of metabolic health. Collectively, this indicates that bariatric surgery creates a specific immunometabolic state with potential implications for health outcomes

    Reprogramming the diseased brain

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    Direct conversion of astrocytes to dopamine neurons in vivo offers fresh optimism for the development of improved Parkinson's therapie

    Colloquium: Statistical mechanics of money, wealth, and income

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    This Colloquium reviews statistical models for money, wealth, and income distributions developed in the econophysics literature since the late 1990s. By analogy with the Boltzmann-Gibbs distribution of energy in physics, it is shown that the probability distribution of money is exponential for certain classes of models with interacting economic agents. Alternative scenarios are also reviewed. Data analysis of the empirical distributions of wealth and income reveals a two-class distribution. The majority of the population belongs to the lower class, characterized by the exponential ("thermal") distribution, whereas a small fraction of the population in the upper class is characterized by the power-law ("superthermal") distribution. The lower part is very stable, stationary in time, whereas the upper part is highly dynamical and out of equilibrium.Comment: 24 pages, 13 figures; v.2 - minor stylistic changes and updates of references corresponding to the published versio

    On well-rounded ideal lattices - II

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    We study well-rounded lattices which come from ideals in quadratic number fields, generalizing some recent results of the first author with K. Petersen. In particular, we give a characterization of ideal well-rounded lattices in the plane and show that a positive proportion of real and imaginary quadratic number fields contains ideals giving rise to well-rounded lattices.Comment: 13 pages; to appear in the International Journal of Number Theor

    Distinct B cell profiles characterise healthy weight and obesity pre- and post-bariatric surgery

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    Funding Information: KO is supported by a Latvian Council of Science Grant Nr. lzp-2020/2-0222 awarded to KO and Nr. lzp-2019/1-0139 awarded to Harijs Čerņevskis. EC Rosser is supported by a Medical Research Foundation Fellowship (MRF-057-0001-RG-ROSS-C0797) and a Senior Research Fellowship from the Kennedy Trust for Rheumatology Research (KENN 21 22 09). Funding Information: KO is supported by a Latvian Council of Science Grant Nr. lzp-2020/2-0222 awarded to KO and Nr. lzp-2019/1-0139 awarded to Harijs Čerņevskis. EC Rosser is supported by a Medical Research Foundation Fellowship (MRF-057-0001-RG-ROSS-C0797) and a Senior Research Fellowship from the Kennedy Trust for Rheumatology Research (KENN 21 22 09). Publisher Copyright: © 2023, The Author(s).BACKGROUND/OBJECTIVES: Obesity-associated metabolic dysfunction and inflammation can be ameliorated by bariatric surgery. While obesity is also linked to impaired B cell activation, differentiation, and persistence in response to infection and vaccination little is known about post-operative immune B cell compartment and to what extent dysregulation in B cell pathways can be reversed. To bridge this gap in knowledge, we carried out in-depth evaluation of B cell composition in individuals with obesity prior to and following bariatric surgery compared to lean controls. SUBJECTS/METHODS: We recruited individuals with obesity (BMI at least 35 kg/m 2) before bariatric surgery (n = 21) and followed them up 6 months post-operatively (n = 17). As controls we recruited age- and sex-matched lean (BMI < 25) individuals (n = 18). We carried out comprehensive immunophenotyping of peripheral blood B cells as well as interrogated their association with inflammatory and metabolic parameters. RESULTS: In obesity the balance of antigen-inexperienced and memory B cells in the peripheral blood is altered, with an expansion of naïve and a reduction in total memory B cells. 6 months following bariatric surgery this balance is restored. However, post-operative patients are uniquely characterised by an increase in B cell subsets associated with chronic inflammation - CD11c +CXCR5 -IgD -CD27 - double negative 2 (DN2) B cells and CD27 +CD38 ++ plasmablasts. Correlations between B cells subsets, inflammatory and metabolic parameters were distinct in lean people and individuals with obesity pre- and post-bariatric surgery. CONCLUSIONS: Bariatric surgery patients display a unique B cell profile 6 months post-operatively; this bears minimal resemblance to that of pre-operative patients and only partially overlaps with that of lean controls. Post-operative differences in the B cell compartment compared to lean controls are detected despite global amelioration of inflammation and restoration of metabolic health. Collectively, this indicates that bariatric surgery creates a specific immunometabolic state with potential implications for health outcomes.Peer reviewe

    Boolean Dynamics with Random Couplings

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    This paper reviews a class of generic dissipative dynamical systems called N-K models. In these models, the dynamics of N elements, defined as Boolean variables, develop step by step, clocked by a discrete time variable. Each of the N Boolean elements at a given time is given a value which depends upon K elements in the previous time step. We review the work of many authors on the behavior of the models, looking particularly at the structure and lengths of their cycles, the sizes of their basins of attraction, and the flow of information through the systems. In the limit of infinite N, there is a phase transition between a chaotic and an ordered phase, with a critical phase in between. We argue that the behavior of this system depends significantly on the topology of the network connections. If the elements are placed upon a lattice with dimension d, the system shows correlations related to the standard percolation or directed percolation phase transition on such a lattice. On the other hand, a very different behavior is seen in the Kauffman net in which all spins are equally likely to be coupled to a given spin. In this situation, coupling loops are mostly suppressed, and the behavior of the system is much more like that of a mean field theory. We also describe possible applications of the models to, for example, genetic networks, cell differentiation, evolution, democracy in social systems and neural networks.Comment: 69 pages, 16 figures, Submitted to Springer Applied Mathematical Sciences Serie
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