3,221 research outputs found
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Differences Between Tourism Professionals’ Value of Sustainable Tourism
This paper is an exploratory investigation to access the value a stakeholder group places on the different dimensions of sustainable tourism. Most definitions of sustainable tourism include three dimensions: economic, social and environmental. This study used on an online survey to determine if members of the Southeast Tourism Society understood that sustainable tourism included all three dimensions, and if they valued those three dimensions differently. Results and conclusions will be presented at the conference
Point-to-Point Multicast Communications Protocol
This paper describes a protocol to support point-to-point interprocessor communications with multicast. Dynamic, cut-through routing with local flow control is used to provide a high-throughput, low-latency communications path between processors. In addition multicast transmissions are available, in which copies of a packet are sent to multiple destinations using common resources as much as possible. Special packet terminators and selective buffering are introduced to avoid a deadlock during multicasts. A simulated implementation of the protocol is also described
Active Galactic Nuclei in Void Regions
We present a comprehensive study of accretion activity in the most underdense
environments in the universe, the voids, based on the SDSS DR2 data. Based on
investigations of multiple void regions, we show that AGN's occurrence rate and
properties differ from those in walls. AGN are more common in voids than in
walls, but only among moderately luminous and massive galaxies (M_r < -20, log
M_*/M_sun < 10.5), and this enhancement is more pronounced for the weakly
accreting systems (i.e., L_[O III] < 10^39 erg/s). Void AGN hosted by
moderately massive and luminous galaxies are accreting at equal or lower rates
than their wall counterparts, show less obscuration than in walls, and
similarly aged stellar populations. The very few void AGN in massive bright
hosts accrete more strongly, are more obscured, and are associated with younger
stellar emission than wall AGN. Thus, accretion strength is probably connected
to the availability of fuel supply, and accretion and star-formation co-evolve
and rely on the same source of fuel. Nearest neighbor statistics indicate that
the weak accretion activity (LINER-like) is not influenced by the local
environment. However, H IIs, Seyferts, and Transition objects prefer more
grouped small scale structures, indicating that the rate at which galaxies
interact with each other affects their activity. These trends support a
potential H II -> Seyfert/Transition Object -> LINER evolutionary sequence that
we show is apparent in many properties of actively line-emitting galaxies, in
both voids and walls. The subtle differences between void and wall AGN might be
explained by a longer, less disturbed duty cycle of these systems in voids.Comment: 19 pages, 7 figures (1 color); to appear in ApJ, submitted on May 11,
200
Compton Scattering of Gamma-Rays from Electrons in Advanced Laboratory
A kinematically-complete 2-body final state measurement of Compton scattering of 662-keV photons is presened, where both scattered photon energy and electron recoil energy are measured versus photon scattering angle, theta gamma. Passive collimation of the photon beam is avoided; each recoiling electron triggers a photon-scattering event providing active beam collimation. Recoiling electrons have low energies at small theta gamma, impairing electron detection efficiency. Examining the recoiling-electron energy spectra in coincidence with high-resolution gammas indicates a 1 x 1 NaI detector is superior to a 1 x1 NE-102 plastic scintillator as the active scattering material, for efficient recoil-electron detection. Electron efficiencies versus theta gamma are measured by comparing e-Y coincident yield with the relativistically-correct Klein-Nishina predictions, indicating the detection-efficiency for recoil-electrons is near 100% at theta gamma \u3e30 degrees. Scattered-photon energy pulses and recoil-electron energy pulses are summed electronically to produce an invariant peak at 662 keV, reducing systematic errors in coincident-yield extraction, In addition, E gamma spectra are taken at several theta gamma to provide an experimental value for electron mass; an easier measurement than the Millikan oil drop experiment, but with similar predictive consequences
Calculation of the unitary part of the Bures measure for N-level quantum systems
We use the canonical coset parameterization and provide a formula with the
unitary part of the Bures measure for non-degenerate systems in terms of the
product of even Euclidean balls. This formula is shown to be consistent with
the sampling of random states through the generation of random unitary
matrices
Using the CERN Program-Library Graphics and Interactive Data Display
Small scale Monte Carlo programming is growing rapidly due to the ease with which complex problems may be formulated by any programmer. These programmers may choose to exploit graphics and interactive displays available in the program library developed and maintained by CERN (the Center for European Nuclear Research). This paper outlines the use of graphics and interactive data display features of the CERN program library, developed for visualizing simulated data events in particle detectors. One example uses GEANT, CERN\u27s Monte Carlo modeling program, to simulate 300 MeV/c protons incident on a silicon slab. Display packages for GEANT are available both on-line and off-line for 3-D tracking of particles through any detector system. On-line displays provide the user a qualitative sense of the inner workings of various detector components. On-line displays may be updated for each particle track in the detector system, so any design change in detector geometry or component material may have its consequences visualized immediately. This visualization is useful for repeatedly making gross changes in the detector system. CERN has been very generous in making its program library available to any institution tied to groups working on experiments at CERN, however peripherally
Multicolour Optical Imaging of IR-Warm Seyfert Galaxies. V. Morphologies and Interactions. Challenging the Orientation Model
This paper is the last in a series, investigating the optical properties of a
sample of mid-IR Warm Seyfert galaxies and of a control sample of mid-IR cold
galaxies. In the present paper we parametrize the morphologies and interaction
properties of the host galaxies and combine these with the major conclusions in
our previous papers. Our results confirm that nuclear activity is linked to
galactic interactions. We suggest an alternative view for the simple
orientation-obscuration model postulated for Seyfert types 1 and 2, that takes
into account the time evolution of their environmental and morphological
properties. Within this view, an evolutionary link between starburst-dominated
and AGN-dominated IR emission is also suggested, to account for the
observational discriminator (mid-IR excess) between our Warm and Cold samples.Comment: 24 pages, including 6 figures and 3 tables (figure 5 included as
independent file), Submitted to Ap
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Examining barriers, motivations, and perceptions of women working in the tourism industry: Case study of Ayampe, Ecuador
The notion of examining gender is gaining momentum across disciplines as an important phenomenon to understand (Kincheloe & Mclaren, 2008). The tourism field is one such area that has made sizeable contributions to the literature; however there is a lack of research focusing on women and tourism in developing countries. This is an exploratory case study of a rural community in Ecuador. Using community-based research methodology and a gender and development framework, this study explores the motivations, barriers and perceptions towards women seeking employment in the tourism industry and identified disparities between the perceptions of men and women in regard to the potential for women securing employment in the industry. The themes that emerged from the data may be grouped as those indicating barriers: gender role expectations, machismo, and poor education; and as motivators: economic benefits, opportunity to learn new things, purpose in life, and education for their children
Orbits of quantum states and geometry of Bloch vectors for -level systems
Physical constraints such as positivity endow the set of quantum states with
a rich geometry if the system dimension is greater than two. To shed some light
on the complicated structure of the set of quantum states, we consider a
stratification with strata given by unitary orbit manifolds, which can be
identified with flag manifolds. The results are applied to study the geometry
of the coherence vector for n-level quantum systems. It is shown that the
unitary orbits can be naturally identified with spheres in R^{n^2-1} only for
n=2. In higher dimensions the coherence vector only defines a non-surjective
embedding into a closed ball. A detailed analysis of the three-level case is
presented. Finally, a refined stratification in terms of symplectic orbits is
considered.Comment: 15 pages LaTeX, 3 figures, reformatted, slightly modified version,
corrected eq.(3), to appear in J. Physics
Electrostatics of Edge States of Quantum Hall Systems with Constrictions: Metal--Insulator Transition Tuned by External Gates
The nature of a metal--insulator transition tuned by external gates in
quantum Hall (QH) systems with point constrictions at integer bulk filling, as
reported in recent experiments of Roddaro et al. [1], is addressed. We are
particularly concerned here with the insulating behavior--the phenomena of
backscattering enhancement induced at high gate voltages. Electrostatics
calculations for QH systems with split gates performed here show that
observations are not a consequence of interedge interactions near the point
contact. We attribute the phenomena of backscattering enhancement to a
splitting of the integer edge into conducting and insulating stripes, which
enable the occurrence of the more relevant backscattering processes of
fractionally charged quasiparticles at the point contact. For the values of the
parameters used in the experiments we find that the conducting channels are
widely separated by the insulating stripes and that their presence alters
significantly the low-energy dynamics of the edges. Interchannel impurity
scattering does not influence strongly the tunneling exponents as they are
found to be irrelevant processes at low energies. Exponents of backscattering
at the point contact are unaffected by interchannel Coulomb interactions since
all channels have same chirality of propagation.Comment: 19 pages; To appear in Phys. Rev.
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