Single transverse-spin asymmetry in Drell-Yan lepton angular distribution

We calculate a single transverse-spin asymmetry for the Drell-Yan lepton-pair's angular distribution in perturbative QCD. At leading order in the strong coupling constant, the asymmetry is expressed in terms of a twist-3 quark-gluon correlation function T_F^{(V)}(x_1,x_2). In our calculation, the same result was obtained in both light-cone and covariant gauge in QCD, while keeping explicit electromagnetic current conservation for the virtual photon that decays into the lepton pair. We also present a numerical estimate of the asymmetry and compare the result to an existing other prediction.Comment: 15 pages, Revtex, 5 Postscript figures, uses aps.sty, epsfig.st

Sleep pattern disruption of flight attendants operating on the Asia–Pacific route

Jet lag is a common issue with flight attendants in international flights, as they have to cross several time zones back and forth, while their sleep patterns get disrupted by the legally required rest times between flights, which are normally carried out at different locations. This research aimed to investigate the sleep quality of a sample of flight attendants operating between New Zealand and Asia. Twenty flight attendants were surveyed in this research. The research found that flight attendants typically took a nap immediately after arriving into New Zealand, reporting a sound sleep time of about 6 hours. After the nap, however, they had problems falling sleep in subsequent nights. After their first nap, some flight attendants try to adapt to local light conditions, while others prefer to keep the sleep patterns they had back home. Both groups report different trends of sleep quality

Keiretsu and Relationship-Specific Investment: Implications for Market-Opening Trade Policy

This paper considers the implications of relationship-specific investment within keiretsu for policies aimed at opening the Japanese market for intermediate goods, such as auto parts. Both VIEs applied to parts and VERs restricting Japanese exports of autos cause the keiretsu to import a wider range of parts, but of a relatively unimportant type, such as seat covers. Since keiretsu investment and output fall, the total value of U.S. parts exports may actually fall. For a given value of these exports, a VIE is less costly for U.S. consumers and Japanese producers, but a VER is preferred by U.S. automakers.

Trade, Capital Redistribution and Firm Structure

A model of heterogeneous firms with multiple products and two production factors (labor and capital) is used to study how trade liberalization affects firms’choices through both product and factor markets. Trade liberalization is shown to always redistribute capital toward more efficient firms and always to improve an industry’s total factor productivity. However, it may reduce capital prices and cause labor productivity to drop. Low efficiency firms are affected mainly by changes in the factor market, while high efficiency firms are affected mainly by changes in the product market. In response to trade liberalization, low efficiency firms always reduce their product scope, but high efficiency firms may expand their scope. The model demonstrates the importance of the interplay between product and factor markets.firm heterogeneity, trade liberalization, multiproduct, multifactor, firm structure, scale, scope, mergers and acquisitions

Keiretsu and Relationship-Specific Investment: A Barrier to Trade?

This paper develops a model of informal procurement within Japanese keiretsu so as to consider effects on intermediate-good imports, such as auto parts. Parts-suppliers make relationship-specific investments that benefit the auto-maker and prices are determined by bargaining after investment has been sunk. Although this investment raises efficiency, it limits the range of imports to less important parts such as tail pipes and it is possible that no parts are imported, despite lower foreign production costs. Lack of information concerning investment rents combined with counterintuitive effects on imports and Japanese production costs could create unwarranted perceptions of a trade barrier.

Surface-mode microcavity

Optical microcavities based on zero-group-velocity surface modes in photonic crystal slabs are studied. It is shown that high quality factors can be easily obtained for such microcavities in photonic crystal slabs. With increasing of the cavity length, the quality factor is gradually enhanced and the resonant frequency converges to that of the zero-group-velocity surface mode in the photonic crystal. The number of the resonant modes with high quality factors is mainly determined by the number of surface modes with zero-group velocity.Comment: 11 pages, 4 figure

Super-reflection and Cloaking Based on Zero Index Metamaterial

A zero index metamaterial (ZIM) can be utilized to block wave (super-reflection) or conceal objects completely (cloaking). The "super-reflection" device is realized by a ZIM with a perfect electric (magnetic) conductor inclusion of arbitrary shape and size for a transverse electric (magnetic) incident wave. In contrast, a ZIM with a perfect magnetic (electric) conductor inclusion for a transverse electric (magnetic) incident wave can be used to conceal objects of arbitrary shape. The underlying physics here is determined by the intrinsic properties of the ZIM

Chromospheric Evaporation in an X1.0 Flare on 2014 March 29 Observed with IRIS and EIS

Chromospheric evaporation refers to dynamic mass motions in flare loops as a result of rapid energy deposition in the chromosphere. These have been observed as blueshifts in X-ray and extreme-ultraviolet (EUV) spectral lines corresponding to upward motions at a few tens to a few hundreds of km/s. Past spectroscopic observations have also revealed a dominant stationary component, in addition to the blueshifted component, in emission lines formed at high temperatures (~10 MK). This is contradictory to evaporation models predicting predominant blueshifts in hot lines. The recently launched Interface Region Imaging Spectrograph (IRIS) provides high resolution imaging and spectroscopic observations that focus on the chromosphere and transition region in the UV passband. Using the new IRIS observations, combined with coordinated observations from the EUV Imaging Spectrometer, we study the chromospheric evaporation process from the upper chromosphere to corona during an X1.0 flare on 2014 March 29. We find evident evaporation signatures, characterized by Doppler shifts and line broadening, at two flare ribbons separating from each other, suggesting that chromospheric evaporation takes place in successively formed flaring loops throughout the flare. More importantly, we detect dominant blueshifts in the high temperature Fe XXI line (~10 MK), in agreement with theoretical predictions. We also find that, in this flare, gentle evaporation occurs at some locations in the rise phase of the flare, while explosive evaporation is detected at some other locations near the peak of the flare. There is a conversion from gentle to explosive evaporation as the flare evolves.Comment: ApJ in pres