143,923 research outputs found

    As Time Goes by ???: Revisiting Fundamentals

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    "Thermometers" of Speculative Frenzy

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    Establishing unambiguously the existence of speculative bubbles is an on-going controversy complicated by the need of defining a model of fundamental prices. Here, we present a novel empirical method which bypasses all the difficulties of the previous approaches by monitoring external indicators of an anomalously growing interest in the public at times of bubbles. From the definition of a bubble as a self-fulfilling reinforcing price change, we identify indicators of a possible self-reinforcing imitation between agents in the market. We show that during the build-up phase of a bubble, there is a growing interest in the public for the commodity in question, whether it consists in stocks, diamonds or coins. That interest can be estimated through different indicators: increase in the number of books published on the topic, increase in the subscriptions to specialized journals. Moreover, the well-known empirical rule according to which the volume of sales is growing during a bull market finds a natural interpretation in this framework: sales increases in fact reveal and pinpoint the progress of the bubble's diffusion throughout society. We also present a simple model of rational expectation which maps exactly onto the Ising model on a random graph. The indicators are then interpreted as ``thermometers'', measuring the balance between idiosyncratic information (noise temperature) and imitation (coupling) strength. In this context, bubbles are interpreted as low or critical temperature phases, where the imitation strength carries market prices up essentially independently of fundamentals. Contrary to the naive conception of a bubble and a crash as times of disorder, on the contrary, we show that bubbles and crashes are times where the concensus is too strong.Comment: 15 pages + 10 figure

    Exegesis of Sect. III.B from “Fundamentals of the Mechanics of Continua” by E. Hellinger

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    This is our third and last exegetic essay on the fundamental review article DIE ALLGEMEINEN ANSÄTZE DER MECHANIK DER KONTINUA in the Encyklopädie der mathematischen Wissenschaften mit Einschluss ihrer Anwendungen, Bd. IV-4, Hft. 5 (1913) by Ernst Hellinger which contains the translation and the commentary of the remaining text starting from p. 663. The six subsections, No. 9–15, deal with the applications of the previously developed conceptual tools to formulate: an effective theory of elasticity, the dynamics of ideal fluids, models for internal friction and elastic hysteresis, a theory of capillarity, optics, the fundamental equations of electrodynamics, an introduction of the thermodynamical foundations and the relationship between the theory of continua and the theory of relativity. Hellinger refers to relevant literature while consolidating in an effective way the contemporary knowledge in 1913. Considering notational differences as being irrelevant for the characterization of the presented scientific content, Hellinger's article shows that an effective compendium of a large part of the insights given in Truesdell and Toupin and Truesdell and Noll has already been available in 1913. We include in this paper an assessment of the different roles played by pioneers, who are innovating their scientific discipline, and by erudite scholars whose role consists in re-ordering existent knowledge and advertising to a wider audience the most important technical results already obtained in a given discipline

    Automatic C library wrapping Ctypes from the trenches

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    At some point of time many Python developers at least in computational science will face the situation that they want to interface some natively compiled library from Python. For binding native code to Python by now a larger variety of tools and technologies are available. This paper focuses on wrapping shared C libraries, using Python's default Ctypes. Particularly tools to ease the process (by using code generation) and some best practises will be stressed. The paper will try to tell a step by step story of the wrapping and development process, that should be transferable to similar problems

    Aerospace medicine and biology. A continuing bibliography (supplement 231)

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    This bibliography lists 284 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1982

    Special Libraries, April 1959

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    Volume 50, Issue 4https://scholarworks.sjsu.edu/sla_sl_1959/1003/thumbnail.jp

    Systems Analysis as a Decision-Making Tool for the Library Manager

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    Experimental evaluation of new pipe sleeve with weep holes for concrete leakage prevention

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    Mortar is a layer with high water absorption rate over concrete due to its porous structure. The mortar layer that frequently exposed to water or moisture is more likely to contain moisture in its layer. The example of area that is mostly exposed to water is the bathroom. The water infiltrated and trapped in the mortar slab in the bathroom will eventually increase the moisture content of the mortar slab and will raise many problems such as the deterioration of the building structure surface. Therefore, this study has been carried out to produce a technology to remove the trapped water in the mortar slab and to reduce the moisture content in the mortar layer. The infiltration rate of the water into the mortar slabs installed with the conventional pipe sleeve (T1), the circular weep-holes pipe sleeve (T2), the vertical weep-holes pipe sleeve (T3) and the inclined weep-holes pipe sleeve (T4) have been measured and the results show that T4 has recorded the highest reading of 7.74 ml/min compared to other pipe sleeves. Besides that, T4 has also recorded the highest water flow rate out of the mortar with 1.31 ml/min and recorded the lowest moisture content of 10.1%. Inclined weep-holes pipe sleeve was proven able to work better than other designs. Therefore, the New Pipe Sleeve (NPS) performance with inclined weep-holes designs are studied in depth by changing the weep-holes angles to 15°, 30°, 45°, 60° and 75° and weep-holes surface area of 6%, 8% and 10%. As a result, the weep-holes angle of 60° with 10% weep-holes surface area has recorded the highest water infiltration rate and water flow rate out of the mortar with 20.898 ml/min and 3.764 ml/min, respectively, obtaining the highest reduction of the moisture content by 3.1%. The optimum performance of the pipe sleeve with inclined weep-holes design has been proposed by using Design Expert Software and the optimum performance can be achieved with the used of the weep-holes angle of 69.55° and 10% weep-holes surface area, producing water infiltration rate of 20.4513 ml/min and water flow rate out of the mortar of 3.3795 ml/min. Therefore, application of optimise design of weep-holes has promising potential method to reduce leakage and fungi problem that normally occurred in bathroom area
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