3,465 research outputs found
The Impact of Tourism on Curacao's Economy: A Scenario Approach
Curaçao is an autonomous countrywithin the Kingdom of the Netherlands. The governmentwants to support tourism development. However,various development strategies are possible. This articlepresents four scenarios of marketing and investmentstrategies that will affect the number of tourists fromThe Netherlands and North America (USA and Canada)in different ways. A multiplier model was used to calculatethe economic impacts of the four scenarios. Bydoing so, this article shows how the government’s decisionto support particular marketing and investmentstrategies may have certain outcomes for the number ofjobs in Curaçao’s tourism industry
Leptonic and semileptonic decays of heavy mesons
A heavy-quark limit of the Dyson-Schwinger equations is introduced and used
in an exploratory study of leptonic and semileptonic decays of heavy mesons.
The application of this framework to heavy-to-light semileptonic decays, which
require a good knowledge of light-quark propagation characteristics and
light-meson bound state amplitudes, is illustrated.Comment: 4 pages, 2 figures, Contribution to the IVth International Workshop
on Progress in Heavy Quark Physics, 20-22 Sept. 1997, Rostoc
Semileptonic decays of heavy mesons
The semileptonic and leptonic decays of heavy mesons are studied as a
phenomenological application and exploration of a heavy-quark limit of
Dyson-Schwinger equations. The single form factor, , which
characterises the semileptonic decay in this limit, is calculated and compares
well with recent experimental extractions. We obtain a lower bound of 1/3 on
the slope-parameter , which, in calculations with
realistic input, is exceeded by a great deal: agreement with experimental data
requiring . The flavour and momentum dependence of the
light-quark propagators has observable consequences.Comment: 11 pages, LaTeX, epsfig.sty, elsart.st
Penerapan Konseling Kelompok Kognitif Perilaku untuk Meningkatkan Harga Diri
Penelitian ini dilatar belakangi oleh rendahnya tingkat harga diri siswa. Tujuan dari penelitian ini adalah untuk menguji ada atau tidaknya perbedaan yang signifikan pada skor tingkat harga diri siswa kelas X-3 SMAN 1 Baureno-Bojonegoro sesudah penggunaan konseling kelompok kognitif perilaku. Angket harga diri digunakan untuk mengukur tingkatan harga diri siswa. Dari angket harga diri dinyatakan bahwa yang menjadi subyek pada penelitian ini adalah delapan siswa kelas X-3 yang memiliki harga diri rendah. Penelitian ini menggunakan desain pre-post test one group design. Teknik analisis data yang digunakan adalah analisis statistik non-parametrik dengan uji tanda. Hasil dari analisis data menunjukkan bahwa ρ = 0,004 lebih kecil dibanding α = 0,05. Dengan demikian maka ada perbedaan antara skor pre-test dan post-test. Berdasarkan hasil penelitian diketahui rata-rata pre-test 110,75 dan rata-rata post-test 141,88. Sehingga terdapat perbedaan skor rata-rata antara pre-test dan post-test sebanyak 31,13. Dengan demikian Ho ditolak dan Ha diterima yang artinya bahwa penerapan konseling kelompok kognitif perilaku dapat meningkatkan harga diri siswa X-3 SMAN 1 Baureno-Bojonegoro.
Kata Kunci : Konseling Kelompok Kognitif Perilaku, Harga Diri Sisw
K_{l3} transition form factors
The rainbow truncation of the quark Dyson-Schwinger equation is combined with
the ladder Bethe-Salpeter equation for the meson bound state amplitudes and the
dressed quark-W vertex in a manifestly covariant calculation of the K_{l3}
transition form factors and decay width in impulse approximation. With model
gluon parameters previously fixed by the chiral condensate, the pion mass and
decay constant, and the kaon mass, our results for the K_{l3} form factors and
the kaon semileptonic decay width are in good agreement with the experimental
data.Comment: 8 pages, 3 figures, Revte
Origin and physics of the highest energy cosmic rays: What can we learn from Radio Astronomy?
Here in this lecture we will touch on two aspects, one the new radio methods
to observe the effects of high energy particles, and second the role that radio
galaxies play in helping us understand high energy cosmic rays. We will focus
here on the second topic, and just review the latest developments in the first.
Radio measurements of the geosynchrotron radiation produced by high energy
cosmic ray particles entering the atmosphere of the Earth as well as radio
\v{C}erenkov radiation coming from interactions in the Moon are another path;
radio observations of interactions in ice at the horizon in Antarctica is a
related attempt. Radio galaxy hot spots are prime candidates to produce the
highest energy cosmic rays, and the corresponding shock waves in relativistic
jets emanating from nearly all black holes observed. We will review the
arguments and the way to verify the ensuing predictions. This involves the
definition of reliable samples of active sources, such as black holes, and
galaxies active in star formation. The AUGER array will probably decide within
the next few years, where the highest energy cosmic rays come from, and so
frame the next quests, on very high energy neutrinos and perhaps other
particles.Comment: 11 pages, To appear in Proceedings of International School of
Astrophysics at Ultra-high Energies, 20-27 June, 2006, Erice, Sicily, Ital
Gaseous optical contamination of the spacecraft environment: A review
Interactions between the ambient atmosphere and orbiting spacecraft, sounding rockets, and suborbital vehicles, and with their effluents, give rise to optical (extreme UV to LWIR) foreground radiation which constitutes noise that raises the detection threshold for terrestrial and celestial radiations, as well as military targets. Researchers review the current information on the on-orbit optical contamination. Its source species are created in interaction processes that can be grouped into three categories: (1) Reactions in the gas phase between the ambient atmosphere and desorbates and exhaust; (2) Reactions catalyzed by exposed ram surfaces, which occur spontaneously even in the absence of active material releases from the vehicles; and (3) Erosive excitative reactions with exposed bulk (organic) materials, which have recently been identified in the laboratory though not as yet observed on spacecraft. Researchers also assess the effect of optical pumping by earthshine and sunlight of both reaction products and effluents
Chiral Symmetry Breaking and Confinement Beyond Rainbow-Ladder Truncation
A non-perturbative construction of the 3-point fermion-boson vertex which
obeys its Ward-Takahashi or Slavnov-Taylor identity, ensures the massless
fermion and boson propagators transform according to their local gauge
covariance relations, reproduces perturbation theory in the weak coupling
regime and provides a gauge independent description for dynamical chiral
symmetry breaking (DCSB) and confinement has been a long-standing goal in
physically relevant gauge theories such as quantum electrodynamics (QED) and
quantum chromodynamics (QCD). In this paper, we demonstrate that the same
simple and practical form of the vertex can achieve these objectives not only
in 4-dimensional quenched QED (qQED4) but also in its 3-dimensional counterpart
(qQED3). Employing this convenient form of the vertex \emph{ansatz} into the
Schwinger-Dyson equation (SDE) for the fermion propagator, we observe that it
renders the critical coupling in qQED4 markedly gauge independent in contrast
with the bare vertex and improves on the well-known Curtis-Pennington
construction. Furthermore, our proposal yields gauge independent order
parameters for confinement and DCSB in qQED3.Comment: 8 pages, 6 figure
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