57 research outputs found
Psychosocial, socio-cultural, and environmental influences on mental health help-seeking among African-American men
http://dx.doi.org/10.1016/j.jomh.2012.03.00
The Business Model: Recent Developments and Future Research
This article provides a broad and multifaceted review of the received literature on business models in which the authors examine the business model concept through multiple subject-matter lenses. The review reveals that scholars do not agree on what a business model is and that the literature is developing largely in silos, according to the phenomena of interest of the respective researchers. However, the authors also found emerging common themes among scholars of business models. Specifically, (1) the business model is emerging as a new unit of analysis; (2) business models emphasize a system-level, holistic approach to explaining how firms “do business”; (3) firm activities play an important role in the various conceptualizations of business models that have been proposed; and (4) business models seek to explain how value is created, not just how it is captured. These emerging themes could serve as catalysts for a more unified study of business models
Renormalization group flows and continual Lie algebras
We study the renormalization group flows of two-dimensional metrics in sigma
models and demonstrate that they provide a continual analogue of the Toda field
equations based on the infinite dimensional algebra G(d/dt;1). The resulting
Toda field equation is a non-linear generalization of the heat equation, which
is integrable in target space and shares the same dissipative properties in
time. We provide the general solution of the renormalization group flows in
terms of free fields, via Backlund transformations, and present some simple
examples that illustrate the validity of their formal power series expansion in
terms of algebraic data. We study in detail the sausage model that arises as
geometric deformation of the O(3) sigma model, and give a new interpretation to
its ultra-violet limit by gluing together two copies of Witten's
two-dimensional black hole in the asymptotic region. We also provide some new
solutions that describe the renormalization group flow of negatively curved
spaces in different patches, which look like a cane in the infra-red region.
Finally, we revisit the transition of a flat cone C/Z_n to the plane, as
another special solution, and note that tachyon condensation in closed string
theory exhibits a hidden relation to the infinite dimensional algebra G(d/dt;1)
in the regime of gravity. Its exponential growth holds the key for the
construction of conserved currents and their systematic interpretation in
string theory, but they still remain unknown.Comment: latex, 73pp including 14 eps fig
A unique hot Jupiter spectral sequence with evidence for compositional diversity
The emergent spectra of close-in, giant exoplanets ("hot Jupiters") are
expected to be distinct from those of self-luminous objects with similar
effective temperatures because hot Jupiters are primarily heated from above by
their host stars rather than internally from the release of energy from their
formation. Theoretical models predict a continuum of dayside spectra for hot
Jupiters as a function of irradiation level, with the coolest planets having
absorption features in their spectra, intermediate-temperature planets having
emission features due to thermal inversions, and the hottest planets having
blackbody-like spectra due to molecular dissociation and continuum opacity from
the H- ion. Absorption and emission features have been detected in the spectra
of a number of individual hot Jupiters, and population-level trends have been
observed in photometric measurements. However, there has been no unified,
population-level study of the thermal emission spectra of hot Jupiters such as
has been done for cooler brown dwarfs and transmission spectra of hot Jupiters.
Here we show that hot Jupiter secondary eclipse spectra centered around a water
absorption band at 1.4 microns follow a common trend in water feature strength
with temperature. The observed trend is broadly consistent with model
predictions for how the thermal structures of solar-composition planets vary
with irradiation level. Nevertheless, the ensemble of planets exhibits some
degree of scatter around the mean trend for solar composition planets. The
spread can be accounted for if the planets have modest variations in
metallicity and/or elemental abundance ratios, which is expected from planet
formation models. (abridged abstract)Comment: 24 pages, 8 figures, published in Nature Astronom
Information sources used by older adults for decision making about tourism and travel destinations
Over the past decade, the older market has emerged as an extremely important one because of its increased purchasing power for most consumer goods and services. The tourism and leisure industry is also targeting people aged 65 years and older, because many possess a relatively large share of discretionary money that they want to spend on travel. This has resulted in increasing attention by the mass media and the advertising industry in particular. This paper discusses the main types of information sources that are used by older adults when they make decisions about tourist and travel destinations, and particularly focuses on the importance of word-of-mouth sources and personal experiences. It also explores the influence of the mass media on trip decision making of older adults, and discusses the importance of brochures, magazines and television as information sources for older adults. Finally, it critiques the lack of senior models in advertising campaigns for travel products that are aimed at the older market
- …