Trade Costs, Conflicts, and Defense Spending

This paper develops a quantitative model of trade, military conflicts, and defense spending. Trade liberalization between two countries reduces probability of an armed conflict between them, causing both to cut defense spending. This in turn causes a domino effect on defense spending by other countries. As a result, both countries and the rest of the world are better off. We estimate the model using data on trade, conflicts, and military spending. We find that, after reduction of costs of trade between a pair of hostile countries, the welfare effect of worldwide defense spending cuts is comparable in magnitude to the direct welfare gains from trade

Permafrost, landscape and ecosystem responses to late Quaternary warm stages in Northeast Siberia

Permafrost, landscape and ecosystem responses to late Quaternary warm stages in Northeast Siberia S. Wetterich1, F. Kienast2, L. Schirrmeister1, M. Fritz1, A. Andreev3, P. Tarasov4 1Alfred Wegener Institute for Polar and Marine Research, Department of Periglacial Research, Potsdam, Germany; 2Senckenberg Research Institute and Natural History Museum, Research Station for Quaternary Palaeontology, Weimar, Germany; 3Institute of Geology and Mineralogy, University of Cologne, Germany; 4Institute of Geological Sciences, Free University Berlin, Germany Perennially frozen ground is widely distributed in Arctic lowlands and beyond. Permafrost responds sensitive to changes in climate conditions. Climate-driven dynamics of landscape, sedimentation and ecology in periglacial regions are frequently recorded in permafrost deposits. The study of late Quaternary permafrost can therefore reveal past glacial-interglacial and stadialinterstadial environmental dynamics. One of the most striking processes under warming climate conditions is the extensive thawing of permafrost (thermokarst) and subsequent surface subsidence. Thermokarst basins promote the development of lakes, whose sedimentological and paleontological records give insights into past interglacial and interstadial (warm). In this paper we present results of qualitative and quantitative reconstructions of climate and environmental conditions for the last Interglacial (MIS 5e, Kazantsevo; ca. 130 to 115 ka ago), the lateglacial Allerød Interstadial (ca. 13 to 11 uncal. ka BP), and the early Holocene (ca. 10.5 to 8 uncal. ka BP). The study was performed in course of the IPY project #15 ‘Past Permafrost’ with permafrost deposits exposed at the coasts of the Dmitry Laptev Strait (East Siberian Sea, East Siberia). The reconstruction based on fossil-rich findings of plants (pollen, macro-remains) and invertebrates (beetles, chironomids, ostracods gastropods). Interglacial vegetation dynamics are reflected in the pollen records by changes from early interglacial grass-sedge-tundra to shrub-tundra during the interglacial thermal optimum followed by grass-sedge-tundra vegetation at the end of the Kazantsevo warm period. Terrestrial beetle and plant remains prove the former existence of open forest tundra with Dahurian larch, grey alder and boreal shrubs interspersed with patches of steppes and meadows during the interglacial thermal optimum. Mean temperature reconstructions of the warmest month (MTWA, TJuly) for the interglacial thermal optimum are based on quantitative chironomid transfer functions revealed a TJuly of 12.9 ± 0.9 °C. The TJuly reconstructed by plant macrofossils amounts to 13.2 ± 0.5 °C, and the pollen-based TJuly reaches 14.3 ± 3.3 °C. Low net precipitation is reflected by steppe plants and beetles. The temperature reconstruction based on three independent approaches. Nethertheless, all methods consistently indicate an interglacial TJuly about 10 °C higher than today, which is interpreted as a result of a combination of increased insolation and higher climatic continentality during the last Interglacial. Grass-sedge dominated tundra vegetation occurred during the lateglacial to Holocene transition which was replaced by shrub tundra during the early Holocene. The presence of Salix and Betula pollen reflects temperatures about 4 °C higher than present between 12 to 11 uncal. ka BP, during the Allerød Interstadial, but shrubs disappeared in the following Younger Dryas stadial, reflecting a climate deterioration. Alnus fruticosa, Betula nana, Poaceae and Cyperaceae dominate early Holocene pollen spectra. Pollen-based reconstructions point to TJuly 4 °C warmer than present. Shrubs gradually disappeared from coastal areas after 7.6 uncal. ka BP when vegetation cover became similar to modern wet tundra. Thermokarst acted as response to warming conditions on landscape scale in permafrost regions. Concurrent changes in relief, hydrology and ecosystems are obvious and detectable by analyses of the paleontological record preserved in thermokarst deposits

Effective Electron Microrefrigeration by SIN Tunnel Junctions with Advanced Geometry of Electrodes and Normal Metal Traps

We demonstrate effective electron cooling of the normal metal strip by superconductor-insulator-normal metal (SIN) tunnel junctions. The improvement was achieved by two methods: first by using an advanced geometry of the superconducting electrodes for more effective removal of the quasiparticles; and second, by adding a normal metal trap just near the cooling junctions. With simple cross geometry and without normal metal traps, the decrease in electron temperature is 56 mK. With the advanced geometry of the superconducting electrodes, the decrease in electron temperature is 129 mK. With the addition of the normal metal traps, the decrease in electron temperature is 197 mK

A Frequency Selective Surface based focal plane receiver for the OLIMPO balloon-borne telescope

We describe here a focal plane array of Cold-Electron Bolometer (CEB) detectors integrated in a Frequency Selective Surface (FSS) for the 350 GHz detection band of the OLIMPO balloon-borne telescope. In our architecture, the two terminal CEB has been integrated in the periodic unit cell of the FSS structure and is impedance matched to the embedding impedance seen by it and provides a resonant interaction with the incident sub-mm radiation. The detector array has been designed to operate in background noise limited condition for incident powers of 20 pW to 80 pW, making it possible to use the same pixel in both photometric and spectrometric configurations. We present high frequency and dc simulations of our system, together with fabrication details. The frequency response of the FSS array, optical response measurements with hot/cold load in front of optical window and with variable temperature black body source inside cryostat are presented. A comparison of the optical response to the CEB model and estimations of Noise Equivalent power (NEP) is also presented

Fuse Selection for the Two-Stage Explosive Type Switches

In the two-level explosive switch destruction of a delay happens in the form of electric explosion. Criteria of similarity of electric explosion in transformer oil are defined. The challenge of protecting the power electrical equipment from short circuit currents is still urgent, especially with the growth of unit capacity. Is required to reduce the tripping time as much as possible, and limit the amplitude of the fault current, that is very important for saving of working capacity of life-support systems. This is particularly important when operating in remote stand-alone power supply systems with a high share of renewable energy, working through the inverter transducers, as well as inverter-type diesel generators. The explosive breakers copes well with these requirements. High-speed flow of transformer oil and high pressure provides formation rate of a contact gap of 20 - 100 m/s. In these conditions there is as a rapid increase in voltage on the discontinuity, and recovery of electric strength (Ures) after current interruption

Transformer Oil Dielectric Strength in the Contact Gap of the Explosive Arc-Extinguishing Device

The article describes the experimental results on the breakdown of the high-speed flow of transformer oil. In real conditions, the flow moves in the contact gap of a high-voltage explosive switch with speeds from 67 to 152 m /s. The geometry of the contact gap is sharply inhomogeneous and forms turbulence in the flow zone. In the arc chute medium the air inclusions pass from the dissolved state to the gaseous and the emerging bubbles enter to the electric field. Breakdown occurs, mainly through gas inclusions. In the moment, the gradient of the breakdown voltage is reduced by 91.6% compared to the static state of the oil. The experiments were carried out on the model of a high-voltage explosive switch, connected to the power circuit of the surge generator. The probing of the gap was made by a standard pulse of 1.5 / 50 [mu]s. As a result, the dependences of the gradient of the breakdown voltage on the flow rate of the transformer oil for the usual geometry of the high-voltage explosive switch contact system are constructed

A Precise Determination of the Running Coupling in the SU(3) Yang-Mills Theory

A non-perturbative finite-size scaling technique is used to study the evolution of the running coupling (in a certain adapted scheme) in the SU(3) Yang-Mills theory. At low energies contact is made with the fundamental dynamical scales, such as the string tension K, while at larger energies the coupling is shown to evolve according to perturbation theory. In that regime the coupling in the MS-bar scheme of dimensional regularization is obtained with an estimated total error of a few percent.Comment: pages 0-27, ps-file 255491 bytes, preprint DESY 93-114 (CERN-TH 6996/93

Two-loop relation between the bare lattice coupling and the MSbar coupling in pure SU(N) gauge theories

We report the result of a computation of the relation between the renormalized coupling in the MSbar scheme of dimensional regularization and the bare coupling in the standard lattice formulation of the SU(N) Yang-Mills theory to two-loop order of perturbation theory and discuss some of its implications.Comment: 10 pages, postscript fil

Accurate Scale Determinations for the Wilson Gauge Action

Accurate determinations of the physical scale of a lattice action are required to check scaling and take the continuum limit. We present a high statistics study of the static potential for the SU(3) Wilson gauge action on coarse lattices ($5.54 \leq \beta \leq 6.0$). Using an improved analysis procedure we determine the string tension and the Sommer scale $r_0$ (and related quantities) to 1% accuracy, including all systematic errors. Combining our results with earlier ones on finer lattices, we present parameterizations of these quantities that should be accurate to about 1% for $5.6 \leq \beta \leq 6.5$. We estimate the \La-parameter of quenched QCD to be \La_\MSb = 247(16) MeV.Comment: 18 pages, LaTeX, 5 ps files (corrected typo in table 5, updated references

Violation of Casimir Scaling for Static QCD Potential at Three-loop Order

We compute the full ${\cal O}(\alpha_s^4)$ and ${\cal O}(\alpha_s^4\log\alpha_s)$ corrections to the potential $V_R(r)$ between the static color sources, where $V_R(r)$ is defined from the Wilson loop in a general representation $R$ of a general gauge group $G$. We find a violation of the Casimir scaling of the potential, for the first time, at ${\cal O}(\alpha_s^4)$. The effect of the Casimir scaling violation is predicted to reduce the tangent of $V_R(r)/C_R$ proportionally to specific color factors dependent on $R$. We study the sizes of the Casimir scaling violation for various $R$'s in the case $G=SU(3)$. We find that they are well within the present bounds from lattice calculations, in the distance region where both perturbative and lattice computations of $V_R(r)$ are valid. We also discuss how to test the Casimir scaling violating effect.Comment: 20 pages, 7 figures, v2: a typo in eq.(13) correcte