1,674 research outputs found
Consumer adoption of online music services: the influence of perceived risks and risk relief strategies
Purpose - The aim of this paper is to offer insights into what consumers are looking for when downloading music and what different consumer groups might look for in commercial online music services, based on their current level of music downloading, and their likelihood of purchasing music online in the near future.
Design/methodology/approach - The literature review focused on the risk and adoption theories. Interviews were used to help derive variables used in the design of a questionnaire. A web survey of 211 samples was used as a data collection method for this study.
Findings - The results suggest that performance and time-loss aspects of perceived risks are playing an important role, while social and psychological aspects of risks are of the least concern to consumers. Where different types of users are concerned, those with the most experience of downloading music are the least profitable segment to target. Non and Light downloaders, on the other hand, should be the focus of marketing activities, although their needs are different.
Originality/value - This paper highlighted that different groups have different behaviours towards downloading music. The finding helps the online music providers to focus on and capture the new age downloaders
Soil Detection using Panchromatic and Infrared Films
Efforts have been made in the soil survey program to improve soil mapping quality. Three types of aerial films were tested to determine if tonal differences exist among the three film types either singularly or in combination which would allow discrimination of soil series within a landscape across several land covers. The imagery consisted of panchromatic (600-700 nm), panchromatic (SOQ-700 nm), and black and white infrared (70Q-900 nm). The utility of these film types for discrimination of the components of soil mapping unit complexes was also tested. Differences were detected between films in the accuracy of discriminating soils due to land cover. The panchromatic (60Q-700 nm) film appeared to be most useful in areas with no land cover, crop residue, and small grain. In areas planted to alfalfa, the greatest accuracy was obtained using panchromatic (60Q-700 nm) or (500-700 nm) film. Generally, the infrared (70Q-900 nm) appeared to be most useful in areas used for pasture-where reflectance characteristics of the grasses are contrasting. Combinations of films improve accuracy in discriminating soils, in areas with no land cover and no crop residue. The combination of panchromatic (600-700 nm) and panchromatic (SOQ-700 nm) films were most useful in improving accuracy on landscape units with no land cover. Combinations of the panchromatic (60Q-700 nm) and infrared (700-900 nm) films were useful within soil groupings with more contrasting soil components. Over-all accuracy in discriminating soils was greater for soils within mapping units than for landscapes
Perturbation of strong Feller semigroups and well-posedness of semilinear stochastic equations on Banach spaces
We prove a Miyadera-Voigt type perturbation theorem for strong Feller
semigroups. Using this result, we prove well-posedness of the semilinear
stochastic equation dX(t) = [AX(t) + F(X(t))]dt + GdW_H(t) on a separable
Banach space E, assuming that F is bounded and measurable and that the
associated linear equation, i.e. the equation with F = 0, is well-posed and its
transition semigroup is strongly Feller and satisfies an appropriate gradient
estimate. We also study existence and uniqueness of invariant measures for the
associated transition semigroup.Comment: Revision based on the referee's comment
Quantum Theory Approach for Neutron Single and Double-Slit Diffraction
We provide a quantum approach description of neutron single and double-slit
diffraction, with specific attention to the cold neutron diffraction (\AA) carried out by Zeilinger et al. in 1988. We find the
theoretical results are good agreement with experimental data.Comment: 10 page
Exponential splitting of bound states in a waveguide with a pair of distant windows
We consider Laplacian in a straight planar strip with Dirichlet boundary
which has two Neumann ``windows'' of the same length the centers of which are
apart, and study the asymptotic behaviour of the discrete spectrum as
. It is shown that there are pairs of eigenvalues around each
isolated eigenvalue of a single-window strip and their distances vanish
exponentially in the limit . We derive an asymptotic expansion also
in the case where a single window gives rise to a threshold resonance which the
presence of the other window turns into a single isolated eigenvalue
Initial Conditions and the Structure of the Singularity in Pre-Big-Bang Cosmology
We propose a picture, within the pre-big-bang approach, in which the universe
emerges from a bath of plane gravitational and dilatonic waves. The waves
interact gravitationally breaking the exact plane symmetry and lead generically
to gravitational collapse resulting in a singularity with the Kasner-like
structure. The analytic relations between the Kasner exponents and the initial
data are explicitly evaluated and it is shown that pre-big-bang inflation may
occur within a dense set of initial data. Finally, we argue that plane waves
carry zero gravitational entropy and thus are, from a thermodynamical point of
view, good candidates for the universe to emerge from.Comment: 18 pages, LaTeX, epsfig. 3 figures included. Minor changes; paragraph
added in the introduction, references added and typos corrected. Final
version published in Classical and Quantum Gravit
Mid-infrared diagnostics of starburst galaxies: clumpy, dense structures in star-forming regions in the Antennae (NGC 4038/4039)
Recently, mid-infrared instruments have become available on several large
ground-based telescopes, resulting in data sets with unprecedented spatial
resolution at these long wavelengths. In this paper we examine
'ground-based-only' diagnostics, which can be used in the study of star-forming
regions in starburst galaxies. By combining output from the stellar population
synthesis code Starburst 99 with the photoionization code Mappings, we model
stellar clusters and their surrounding interstellar medium, focusing on the
evolution of emission lines in the N- and Q-band atmospheric windows (8-13 and
16.5-24.5 micron respectively) and those in the near-infrared. We address the
detailed sensitivity of various emission line diagnostics to stellar population
age, metallicity, nebular density, and ionization parameter. Using our model
results, we analyze observations of two stellar clusters in the overlap region
of the Antennae galaxies obtained with VLT Imager and Spectrometer for mid
Infrared (VISIR). We find evidence for clumpy, high density, ionized gas. The
two clusters are young (younger than 2.5 and 3 Myr respectively), the
surrounding interstellar matter is dense (10^4 cm^-3 or larger) and can be
characterized by a high ionization parameter (logU > -1.53). Detailed analysis
of the mid-infrared spectral features shows that a (near-)homogeneous medium
cannot account for the observations, and that complex structure on scales below
the resolution limit, containing several young stellar clusters embedded in
clumpy gas, is more likely.Comment: 24 pages, 16 figures (3 in color), accepted for publication in Ap
Bianchi VIII Empty Futures
Using a qualitative analysis based on the Hamiltonian formalism and the
orthonormal frame representation we investigate whether the chaotic behaviour
which occurs close to the initial singularity is still present in the far
future of Bianchi VIII models. We describe some features of the vacuum Bianchi
VIII models at late times which might be relevant for studying the nature of
the future asymptote of the general vacuum inhomogeneous solution to the
Einstein field equations.Comment: 22 pages, no figures, Latex fil
High-Resolution Imaging of Molecular Gas and Dust in the Antennae (NGC 4038/39): Super Giant Molecular Complexes
We present new aperture synthesis CO maps of the Antennae (NGC 4038/39)
obtained with the Caltech Millimeter Array. These sensitive images show
molecular emission associated with the two nuclei and a partial ring of star
formation to the west of NGC 4038, as well as revealing the large extent of the
extra-nuclear region of star formation (the ``overlap region''), which
dominates the CO emission from this system. The largest molecular complexes
have masses of 3-6x10^8 M_sun, typically an order of magnitude larger than the
largest structures seen to date in more quiescent galaxy disks. The extremely
red luminous star clusters identified previously with HST are well-correlated
with the CO emission, which supports the conclusion that they are highly
embedded young objects rather than old globular clusters. There is an excellent
correlation between the CO emission and the 15 micron emission seen with ISO,
particularly for the brightest regions. The most massive complexes in the
overlap region have similar [NeIII]/[NeII] ratios, which implies that all these
regions are forming many massive stars. However, only the brightest
mid-infrared peak shows strong, rising continuum emission longward of 10
microns, indicative of very small dust grains heated to high temperatures by
their proximity to nearby luminous stars. Since these grains are expected to be
removed rapidly from the immediate environment of the massive stars, it is
possible that this region contains very young (< 1 Myr) sites of star
formation. Alternatively, fresh dust grains could be driven into the sphere of
influence of the massive stars, perhaps by the bulk motions of two giant
molecular complexes. The kinematics and morphology of the CO emission in this
region provide some support for this second scenario.Comment: Accepted for publication in The Astrophysical Journal, 13 pages, 5
figures, higher quality color images available at
http://www.astro.cornell.edu/staff/vassilis/papers/ngc4038_co.ps.g
- …