1,106 research outputs found

    Comparing the correlation length of grain markets in China and France

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    In economics comparative analysis plays the same role as experimental research in physics. In this paper we closely examine several methodological problems related to comparative analysis by investigating the specific example of grain markets in China and France respectively. This enables us to answer a question in economic history which has so far remained pending, namely whether or not market integration progressed in the 18th century. In economics as in physics, before being accepted any new result has to be checked and re-checked by different researchers. This is what we call the replication and comparison procedures. We show how these procedures should (and can) be implemented.Comment: 16 pages, 7 figures, to appear in International Journal of Modern Physics

    Mission Design and Analysis for Suborbital Intercept and Fragmentation of an Asteroid with Very Short Warning Time

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    Small near-Earth objects (NEOs) approximately 50-150 m in size are far more numerous (hundreds of thousands to millions yet to be discovered) than larger NEOs. Small NEOs, which are mostly asteroids rather than comets, are very faint in the night sky due to their small sizes, and are, therefore, difficult to discover far in advance of Earth impact. Furthermore, even small NEOs are capable of creating explosions with energies on the order of tens or hundreds of megatons (Mt). We are, therefore, motivated to prepare to respond effectively to short warning time, small NEO impact scenarios. In this paper we explore the lower bound on actionable warning time by investigating the performance of notional upgraded Intercontinental Ballistic Missiles (ICBMs) to carry Nuclear Explosive Device (NED) payloads to intercept and disrupt a hypothetical incoming NEO at high altitudes (generally at least 2500 km above Earth). We conduct this investigation by developing optimal NEO intercept trajectories for a range of cases and comparing their performances. Our results show that suborbital NEO intercepts using Minuteman III or SM-3 IIA launch vehicles could achieve NEO intercept a few minutes prior to when the NEO would strike Earth. We also find that more powerful versions of the launch vehicles (e.g., total delta V of approximately 9.5-11 km/s) could intercept incoming NEOs several hours prior to when the NEO would strike Earth, if launched at least several days prior to the time of intercept. Finally, we discuss a number of limiting factors and practicalities that affect whether the notional systems we describe could become feasible

    Barro's fertility equations: the robustness of the role of female education and income

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    Barro and Lee (1994) and Barro and Sala-i-Martin (1995) find that real per-capita GDP and both male and female education have important effects on fertility in their cross-country empirical studies. In order to assess the robustness of their results, their estimated models are subjected to specification and diagnostic testing, the effects on the model of using the improved Barro and Lee (1996) cross-country data on educational attainment of the population aged 15 and over are examined, and the different specifications used by Barro and Lee and by Barro and Sala-i-Martin compared. The results obtained suggest that their fertility equations do not perform well in terms of diagnostic testing, and are very sensitive to the use of different vintages of the educational attainment proxies and of the Summers-Heston cross-country income data. A robust explanation of fertility, to link with empirical growth equations, has, therefore, not yet been found; further work is required in this area

    How to make experimental economics research more reproducible: lessons from other disciplines and a new proposal

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    Efforts in the spirit of this special issue aim at improving the reproducibility of experimental economics, in response to the recent discussions regarding the “research reproducibility crisis.” We put this endeavour in perspective by summarizing the main ways (to our knowledge) that have been proposed – by researchers from several disciplines – to alleviate the problem. We discuss the scope for economic theory to contribute to evaluating the proposals. We argue that a potential key impediment to replication is the expectation of negative reactions by the authors of the individual study, and suggest that incentives for having one’s work replicated should increase

    Lifetime Measurements in 120Xe

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    Lifetimes for the lowest three transitions in the nucleus 120^{120}Xe have been measured using the Recoil Distance Technique. Our data indicate that the lifetime for the 21+01+2_{1}^{+} \to 0_{1}^{+} transition is more than a factor of two lower than the previously adopted value and is in keeping with more recent measurements performed on this nucleus. The theoretical implications of this discrepancy and the possible reason for the erroneous earlier results are discussed. All measured lifetimes in 120^{120}Xe, as well as the systematics of the lifetimes of the 21+_{1}^{+} states in Xe isotopes, are compared with predictions of various models. The available data are best described by the Fermion Dynamic Symmetry Model (FDSM).Comment: 9 pages, RevTeX, 3 figures with Postscript file available on request at [email protected], [email protected]. Submitted to Phys. Rev.

    Естественная радиоактивность кольчугинской серии отложений Ленинского геолого-экономического района Кузбасса

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    Рассматриваются на основании исследования 1435 образцов горных пород естественные радиоактивные свойства мелко- и крупнозернистого алевролитов и мелкозернистого песчаника, а также каменных углей. Отмечается различие по естественной радиоактивности между основными литологическими разностями пород, слагающих кольчугинскую серию. Естественная радиоактивность пород закономерно уменьшается от алевролитов к песчаникам и к углям. Угли по естественной радиоактивности резко отличаются от вмещающих пород

    Supervisors’ Experiences of Providing Difficult Feedback in Cross-Ethnic/Racial Supervision

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    Seventeen clinical supervisors were interviewed regarding their experience of providing difficult feedback in cross-ethnic/racial supervision, and their responses were analyzed using consensual qualitative research (CQR). European American supervisors described supervisees of color who had difficulty in their clinical work with culturally different clients. These supervisors then shared with supervisees their concern that supervisees’ interpersonal skills may negatively affect their clinical and/or supervision work. Supervisors of color described European American supervisees who exhibited insensitivity toward clients of color in session or during supervision. These supervisors shared their concern that supervisees’ lack of cultural sensitivity may negatively affect their clinical work. These contrasting feedback experiences had a profound effect on supervisory relationships and the processes within supervision

    Sedimentological evidence for pronounced glacial‐interglacial climate fluctuations in NE Tibet in the latest Pliocene to early Pleistocene

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    The intensification of Northern Hemisphere glaciation (iNHG) and uplift of the Tibetan Plateau have been argued to be among the main drivers of climate change in midlatitude Central Asia during the Pliocene/Pleistocene. While most proxy records that support this hypothesis are from regions outside the Tibetan Plateau (such as from the Chinese Loess Plateau), detailed paleoclimatic information for the plateau itself during that time has yet remained elusive. Here we present a temporally highly resolved (~500 years) sedimentological record from the Qaidam Basin situated on the northeastern Tibetan Plateau that shows pronounced glacial‐interglacial climate variability during the interval from 2.7 to 2.1 Ma. Glacial (interglacial) intervals are generally characterized by coarser (finer) grain size, minima (maxima) in organic matter content, and maxima (minima) in carbonate content. Comparison of our results with Earth's orbital parameters and proxy records from the Chinese Loess Plateau suggests that the observed climate fluctuations were mainly driven by changes in the Siberian High/East Asian winter monsoon system as a response to the iNHG. They are further proposed to be enhanced by the topography of the Tibetan Plateau and its impact on the position and intensity of the westerlies
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