Handling qualities aspects of NASA YF-12 flight experience

The handling qualities of the YF-12 airplane as observed during NASA research flights over the past five years were reviewed. Aircraft behavior during takeoff, acceleration, climb, cruise, descent, and landing are discussed. Pilot comments on the various flight phases and tasks are presented. Handling qualities parameters such as period, damping, amplitude ratios, roll-yaw coupling, and flight path response sensitivity are compared to existing and proposed handling qualities criteria. The influence of the propulsion systems, stability augmentation, autopilot systems, atmospheric gusts, and temperature changes are also discussed. YF-12 experience correlates well with flying qualities criteria, except for longitudinal short period damping, where existing and proposed criteria appear to be more stringent than necessary

Non-equilibrium fluctuations and mechanochemical couplings of a molecular motor

We investigate theoretically the violations of Einstein and Onsager relations, and the efficiency for a single processive motor operating far from equilibrium using an extension of the two-state model introduced by Kafri {\em et al.} [Biophys. J. {\bf 86}, 3373 (2004)]. With the aid of the Fluctuation Theorem, we analyze the general features of these violations and this efficiency and link them to mechanochemical couplings of motors. In particular, an analysis of the experimental data of kinesin using our framework leads to interesting predictions that may serve as a guide for future experiments.Comment: 4 pages, 4 figures, accepted to Phys. Rev. Let

Multi-parameter deformed and nonstandard Y(glM)Y(gl_M) Yangian symmetry in integrable variants of Haldane-Shastry spin chain

By using `anyon like' representations of permutation algebra, which pick up nontrivial phase factors while interchanging the spins of two lattice sites, we construct some integrable variants of Haldane-Shastry (HS) spin chain. Lax equations for these spin chains allow us to find out the related conserved quantities. However, it turns out that such spin chains also possess a few additional conserved quantities which are apparently not derivable from the Lax equations. Identifying these additional conserved quantities, and the usual ones related to Lax equations, with different modes of a monodromy matrix, it is shown that the above mentioned HS like spin chains exhibit multi-parameter deformed and `nonstandard' variants of $Y(gl_M)$ Yangian symmetry.Comment: 18 pages, latex, no figure

Knowledge spillovers and output per worker: an industry-level analysis for OECD countries

This study analyzes the impact of knowledge spillovers on output per worker at the industry level using a primal production function approach. The article makes three different contributions to the international spillovers literature: (1) it identifies trade related spillovers under alternative assumptions regarding the information transferred through imports; (2) it explores the importance of horizontal and vertical foreign direct investment (FDI) in knowledge spillovers; and (3) it looks at how institutional factors determine the impact of FDI-related spillovers on productivity. The main findings of the study are: (1) international knowledge spillover is an important driver of industry output per worker, and the magnitude of this spillover effect varies with alternative assumptions about the information content embodied in imports, while high technology industries benefit significantly more from import-related knowledge spillovers; and (2) the gains from FDI spillovers are primarily horizontal, but when institutional factors are considered, countries with stronger protection of intellectual property rights and a high “ease of doing business” tend to experience a substantial increase in the effectiveness of both horizontal and vertical FDI-related spillover

Knowledge spillovers, absorptive capacity and growth: an industry-level analysis for OECD countries

Given the decline in growth momentum in the manufacturing sector in many OECD countries, the role of knowledge-based capital has emerged as a key driver for sustained growth. While empirical studies on estimating knowledge spillovers have usually been undertaken at the country level, the spillover effects can be more definitive only if the analysis is conducted at the industry-level. The effectiveness of international spillovers is conditional on recipient country’s absorptive capacity and this is an important component of the spillover mechanism that has not attracted significant attention so far. This paper therefore assesses the effect of spillovers in driving per capita output growth taking into account the role of absorptive capacity. Our main findings are first, the confirmation of the robust positive relationship between human capital and output growth for 14 OECD countries at industry level. Second, the gains from international spillover are conditional to the level of human capital and the degree of protection of intellectual property rights. Third, countries that improve absorptive capacity can potentially increase gains from spillovers via either trade or FDI (including vertical FDI). Finally, significant heterogeneity is found between high and low-tech industries. The former group is more effective in absorbing spillovers while the latter has failed to reach the critical level of technological advancement in order to absorb foreign and domestic knowledge