Net profitability of airline alliances, an empirical study

This study examines the net return for airlines before and after joining an alliance. The research database was compiled from ICAOData, and comprised 15 international airlines as subjects and their net financial results for a period of 11 years as primary research variables. Two variables, the averages of five and three years net performance before joining an alliance, were tested against another variable, the average net performance five years after joining the alliance. Results show a deterioration of net profits after joining an alliance, although this trend was only significant when comparing performance over the short-term. However, the performance of American airlines accounted for most of this trend, which may have being partly affected by the consequences of September 11 2001

The net profitability of airline alliances using referential dollars

This study revises a previous research in which we analysed the net profitability of airline alliances but did not control for the impact of inflation on such profitability. Using the same methodology, 15 international airlines as subjects and their net financial results for a period of 11 years as primary research variables, we now compared the performance of airlines before and after joining their respective alliances using referential dollars (i.e., constant dollars with 2010 as base year) instead of nominal dollars. The results showed a similar deterioration in short-term net profits after joining an alliance as the previous study did, and a similar behaviour of statistics tests. Thus, the conclusion then achieved still stand after this revision

Ground state properties of a Tonks-Girardeau Gas in a periodic potential

In this paper, we investigate the ground-state properties of a bosonic Tonks-Girardeau gas confined in a one-dimensional periodic potential. The single-particle reduced density matrix is computed numerically for systems up to $N=265$ bosons. Scaling analysis of the occupation number of the lowest orbital shows that there are no Bose-Einstein Condensation(BEC) for the periodically trapped TG gas in both commensurate and incommensurate cases. We find that, in the commensurate case, the scaling exponents of the occupation number of the lowest orbital, the amplitude of the lowest orbital and the zero-momentum peak height with the particle numbers are 0, -0.5 and 1, respectively, while in the incommensurate case, they are 0.5, -0.5 and 1.5, respectively. These exponents are related to each other in a universal relation.Comment: 9 pages, 10 figure

Nature of Quasielectrons and the Continuum of Neutral Bulk Excitations in the Laughlin Quantum Hall Fluids

We construct model wavefunctions for a family of single-quasielectron states supported by the $\nu=1/3$ fractional quantum Hall (FQH) fluid. The charge $e^*$ = $e/3$ quasielectron state is identified as a composite of a charge-$2e^*$ quasiparticle and a $-e^*$ quasihole, orbiting around their common center of charge with relative angular momentum $n\hbar > 0$, and corresponds precisely to the "composite fermion" construction based on a filled $n=0$ Landau level plus an extra particle in level $n > 0$. An effective three-body model (one $2e^*$ quasiparticle and two $-e^*$ quasiholes) is introduced to capture the essential physics of the neutral bulk excitations.Comment: 4 pages, 3 figs, minor modifications for the published versio

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

Analytic description of atomic interaction at ultracold temperatures II: Scattering around a magnetic Feshbach resonance

Starting from a multichannel quantum-defect theory, we derive analytic descriptions of a magnetic Feshbach resonance in an arbitrary partial wave $l$, and the atomic interactions around it. An analytic formula, applicable to both broad and narrow resonances of arbitrary $l$, is presented for ultracold atomic scattering around a Feshbach resonance. Other related issues addressed include (a) the parametrization of a magnetic Feshbach resonance of arbitrary $l$, (b) rigorous definitions of "broad" and "narrow" resonances of arbitrary $l$ and their different scattering characteristics, and (c) the tuning of the effective range and the generalized effective range by a magnetic field.Comment: 13 pages, 4 figure