Ray class fields of global function fields with many rational places

A general type of ray class fields of global function fields is investigated. The systematic computation of their genera leads to new examples of curves over finite fields with comparatively many rational points.Comment: Latex2e, 27 pages, 20 tables, revised version as submitted to Acta Arithmetic

Ball bearing versus magnetic bearing reaction and momentum wheels as momentum actuators

Different bearing technologies of momentum actuators for the attitude control of satellites are compared and a guideline for the selection of the suitable momentum actuators or momentum actuator configurations to meet given mission goals with high reliability and low cost is developed. The comparison between ball bearing and magnetic bearing momentum actuators shows that given mission requirements can be economically met by employing the ball bearing technology without decreasing reliability and lifetime. However, for some special mission requirements, such as 'zero friction at zero speed,' fine pointing (met by vernier gimballing), and/or active damping, magnetic bearings may be advantageous. This makes it evident that magnetic bearing technology will not replace ball bearing technology for momentum actuators, but will supplement it for some special mission requirements

Micrometeoroid velocity-and-trajectory analyzer

By adding potential energy of charged capacitor to kinetic energy of impacting particle, new technique causes major fraction of atoms in microscopic particle impacting on particle-receiving surface to be ionized. Chemical constituents of impacting particle are represented by generated ion mass spectrum in approximately correct proportions

Particle impact location detector

Detector includes delay lines connected to each detector surface strip. When several particles strike different strips simultaneously, pulses generated by each strip are time delayed by certain intervals. Delay time for each strip is known. By observing time delay in pulse, it is possible to locate strip that is struck by particle

The Colonial and Geographic Origins of Comparative Development

While the direct impact of geographic endowments on prosperity is present in all countries, in former colonies, geography has also affected colonization policies and, therefore, institutional outcomes. Using non-colonized countries as a control group, I develop an empirical strategy that disentangles the partial effects of institutions and of endowments on income. I find that institutions are the main determinant of development, but that endowments have a sizeable direct impact, as well. Last, I apply the empirical strategy to examine the theories put forward by La Porta et al. (1999) and by Acemoglu et al. (2001), finding support for both theories, but also evidence that the authors’ estimates are biased since they mix up the effect of the historical determinants of institutions with the sizeable direct impact of access to trade and of disease environment.

Exchange rate pass-through, domestic competition and inflation -- evidence from the 2005/08 revaluation of the Renminbi

How important is the effect of exchange rate fluctuations on the competitive environment faced by domestic firms and the prices they charge? To answer this question, this paper examines the 17 percent appreciation of the yuan against the U.S. dollar from 2005 to 2008. In a monthly panel covering 110 sectors, a 1 percent appreciation of the Yuan increases U.S. import prices by roughly 0.8 percent. It is then shown that import prices, in turn, pass through into producer prices at an average rate of roughly 0.7, implying that a 1 percent Yuan appreciation increases the average U.S. producer price of tradable goods by 0.8 percent*0.7=0.56 percent. In contrast, exchange rate movements of other trade partners have much smaller effects on import prices and hardly any effect on producer prices. The paper next demonstrates that the pass through response into import prices is heterogeneous across sectors with different characteristics such as traded-input intensity or the shape of demand for the sector's goods. In contrast, the rate at which import prices pass through into domestic producer prices is found to be homogenous across the sectors. Finally, the insights of the analysis are employed to simulate the inflationary effect of a Yuan revaluation. For example, the relative price shock caused by a 25 percent appreciation of the Yuan spread evenly over 10 months is equivalent to a temporary increase of the U.S. PPI inflation rate by over five percentage points. Because such an appreciation would also influence the overall skewness of the distribution of price changes at the sectoral level, it would likely also impact U.S. equilibrium inflation.Imports - Prices ; International trade ; Labor market ; Macroeconomics ; Price levels

Product Heterogeneity, Within-Industry Trade Patterns, and the Home Bias of Consumption?

Starting with Krugman (1980), much literature has analyzed how trade liberalization affects the economy based on the notion that trade is motivated by consumer’s love of variety. In this paper, I augment these preferences by the determinants of demand for heterogeneous products. The model features products with heterogeneous attributes and consumers with heterogeneous tastes for attributes. Allowing for international trade, the model predicts a within-industry home market effect, i.e., that high domestic demand for an attribute leads to entry of firms producing a fitting output and, consequently, net exports of products embodying the attribute. Second, the model rationalizes why consumption is home-biased in the short run. Each country’s industry is optimized for the preferences of domestic consumers and thus somewhat inappropriate for the export market. Third, in the long run, countries specialize further and the within-industry home market effect intensifies. Intriguingly, (as long as it is incomplete) this specialization implies that the home bias disappears completely, thus demonstrating that Linder’s (1961) conjecture describes a temporary phenomenon that does not prevail in general equilibrium