4,744 research outputs found
Phase separation of binary condensates in harmonic and lattice potentials
We propose a modified Gaussian ansatz to study binary condensates, trapped in
harmonic and optical lattice potentials, both in miscible and immiscible
domains. The ansatz is an apt one as it leads to the smooth transition from
miscible to immiscible domains without any {\em a priori} assumptions. In
optical lattice potentials, we analyze the squeezing of the density profiles
due to the increase in the depth of the optical lattice potential. For this we
develop a model with three potential wells, and define the relationship between
the lattice depth and profile of the condensate.Comment: 13 pages, 11 figures, additional references adde
Neutrino mass and magnetic moment in supersymmetry without R-parity in the light of recent data
We consider the generation of neutrino Majorana mass and transition magnetic
moment by the lepton-number violating and/or couplings in
R-parity-violating supersymmetric models. We update (and improve) the existing
upper limits on the relevant couplings using the most recent data on neutrino
masses and mixings, indicating also the possible improvement by the GENIUS
project. We study the implication of this update on the induced neutrino
magnetic moment.Comment: 7 pages, Latex, uses axodraw.sty; refs updated, to appear in PL
Aerodynamic Effects and Modeling of Damage to Transport Aircraft
A wind tunnel investigation was conducted to measure the aerodynamic effects of damage to lifting and stability/control surfaces of a commercial transport aircraft configuration. The modeling of such effects is necessary for the development of flight control systems to recover aircraft from adverse, damage-related loss-of-control events, as well as for the estimation of aerodynamic characteristics from flight data under such conditions. Damage in the form of partial or total loss of area was applied to the wing, horizontal tail, and vertical tail. Aerodynamic stability and control implications of damage to each surface are presented, to aid in the identification of potential boundaries in recoverable stability or control degradation. The aerodynamic modeling issues raised by the wind tunnel results are discussed, particularly the additional modeling requirements necessitated by asymmetries due to damage, and the potential benefits of such expanded modeling
Low-speed Wind-Tunnel Study of Reaction Control-jet Effectiveness for Hover and Transition of a STOVL Fighter Concept
A brief wind-tunnel study was conducted in the Langley 12-Foot Low-Speed Tunnel to determine reaction control-jet effectiveness and some associated aerodynamic characteristics of a 15 percent scale model of the General Dynamics E-7A STOVL fighter/attack aircraft concept applicable to hover and transition flight. Tests were made with the model at various attitude angles in the tunnel test section and at various tunnel airspeeds for a range of control-jet nozzle pressure ratios. Eight reaction control-jets were tested individually. Four jets were at the design baseline locations providing roll, pitch, and yaw control. Comparisons of measured data with values calculated using empirical methods were made where possible
RRR: Rank-Regret Representative
Selecting the best items in a dataset is a common task in data exploration.
However, the concept of "best" lies in the eyes of the beholder: different
users may consider different attributes more important, and hence arrive at
different rankings. Nevertheless, one can remove "dominated" items and create a
"representative" subset of the data set, comprising the "best items" in it. A
Pareto-optimal representative is guaranteed to contain the best item of each
possible ranking, but it can be almost as big as the full data. Representative
can be found if we relax the requirement to include the best item for every
possible user, and instead just limit the users' "regret". Existing work
defines regret as the loss in score by limiting consideration to the
representative instead of the full data set, for any chosen ranking function.
However, the score is often not a meaningful number and users may not
understand its absolute value. Sometimes small ranges in score can include
large fractions of the data set. In contrast, users do understand the notion of
rank ordering. Therefore, alternatively, we consider the position of the items
in the ranked list for defining the regret and propose the {\em rank-regret
representative} as the minimal subset of the data containing at least one of
the top- of any possible ranking function. This problem is NP-complete. We
use the geometric interpretation of items to bound their ranks on ranges of
functions and to utilize combinatorial geometry notions for developing
effective and efficient approximation algorithms for the problem. Experiments
on real datasets demonstrate that we can efficiently find small subsets with
small rank-regrets
China's Economic Reforms: Chronology and Statistics
At the end of the twentieth century, the People's Republic of China faces stark trade policy choices. Market reforms implemented since 1978 have brought commercial strength and bright expectations for future prosperity. However, they have also brought China to the point where trading partners insist on commitments to liberal, internationally recognized trading principles. These calls come at a time when China is seeking to enter the World Trade Organization (WTO), is negotiating bilateral trade agreements with Europe, United States and its emerging neighbors, and is working out the terms of its participation in the ambitious Asia Pacific Economic Cooperation (APEC) forum.
Estimating the Economic Impact of Disease on a Local Economy: The Case of Diabetes in the Lower Rio Grande Valley of Texas
The purpose of this study is to investigate the economic impact of wage reductions that people experience from contracting diabetes. Incorporating wage reduction information into an input-output model reveals that as diabetics' wages decrease by 0.36 and $0.38, respectively.Health Economics and Policy,
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