180 research outputs found
Variational bound on energy dissipation in plane Couette flow
We present numerical solutions to the extended Doering-Constantin variational
principle for upper bounds on the energy dissipation rate in turbulent plane
Couette flow. Using the compound matrix technique in order to reformulate this
principle's spectral constraint, we derive a system of equations that is
amenable to numerical treatment in the entire range from low to asymptotically
high Reynolds numbers. Our variational bound exhibits a minimum at intermediate
Reynolds numbers, and reproduces the Busse bound in the asymptotic regime. As a
consequence of a bifurcation of the minimizing wavenumbers, there exist two
length scales that determine the optimal upper bound: the effective width of
the variational profile's boundary segments, and the extension of their flat
interior part.Comment: 22 pages, RevTeX, 11 postscript figures are available as one
uuencoded .tar.gz file from [email protected]
Finding a moral homeground: appropriately critical religious education and transmission of spiritual values
Values-inspired issues remain an important part of the British school curriculum. Avoiding moral relativism while fostering enthusiasm for spiritual values and applying them to non-curricular learning such as school ethos or children's home lives are challenges where spiritual, moral, social and cultural (SMSC) development might benefit from leadership by critical religious education (RE). Whether the school's model of spirituality is that of an individual spiritual tradition (schools of a particular religious character) or universal pluralistic religiosity (schools of plural religious character), the pedagogy of RE thought capable of leading SMSC development would be the dialogical approach with examples of successful implementation described by Gates, Ipgrave and Skeie. Marton's phenomenography, is thought to provide a valuable framework to allow the teacher to be appropriately critical in the transmission of spiritual values in schools of a particular religious character as evidenced by Hella's work in Lutheran schools
Good Friends, Bad News - Affect and Virality in Twitter
The link between affect, defined as the capacity for sentimental arousal on
the part of a message, and virality, defined as the probability that it be sent
along, is of significant theoretical and practical importance, e.g. for viral
marketing. A quantitative study of emailing of articles from the NY Times finds
a strong link between positive affect and virality, and, based on psychological
theories it is concluded that this relation is universally valid. The
conclusion appears to be in contrast with classic theory of diffusion in news
media emphasizing negative affect as promoting propagation. In this paper we
explore the apparent paradox in a quantitative analysis of information
diffusion on Twitter. Twitter is interesting in this context as it has been
shown to present both the characteristics social and news media. The basic
measure of virality in Twitter is the probability of retweet. Twitter is
different from email in that retweeting does not depend on pre-existing social
relations, but often occur among strangers, thus in this respect Twitter may be
more similar to traditional news media. We therefore hypothesize that negative
news content is more likely to be retweeted, while for non-news tweets positive
sentiments support virality. To test the hypothesis we analyze three corpora: A
complete sample of tweets about the COP15 climate summit, a random sample of
tweets, and a general text corpus including news. The latter allows us to train
a classifier that can distinguish tweets that carry news and non-news
information. We present evidence that negative sentiment enhances virality in
the news segment, but not in the non-news segment. We conclude that the
relation between affect and virality is more complex than expected based on the
findings of Berger and Milkman (2010), in short 'if you want to be cited: Sweet
talk your friends or serve bad news to the public'.Comment: 14 pages, 1 table. Submitted to The 2011 International Workshop on
Social Computing, Network, and Services (SocialComNet 2011
Solving Nonlinear Parabolic Equations by a Strongly Implicit Finite-Difference Scheme
We discuss the numerical solution of nonlinear parabolic partial differential
equations, exhibiting finite speed of propagation, via a strongly implicit
finite-difference scheme with formal truncation error . Our application of interest is the spreading of
viscous gravity currents in the study of which these type of differential
equations arise. Viscous gravity currents are low Reynolds number (viscous
forces dominate inertial forces) flow phenomena in which a dense, viscous fluid
displaces a lighter (usually immiscible) fluid. The fluids may be confined by
the sidewalls of a channel or propagate in an unconfined two-dimensional (or
axisymmetric three-dimensional) geometry. Under the lubrication approximation,
the mathematical description of the spreading of these fluids reduces to
solving the so-called thin-film equation for the current's shape . To
solve such nonlinear parabolic equations we propose a finite-difference scheme
based on the Crank--Nicolson idea. We implement the scheme for problems
involving a single spatial coordinate (i.e., two-dimensional, axisymmetric or
spherically-symmetric three-dimensional currents) on an equispaced but
staggered grid. We benchmark the scheme against analytical solutions and
highlight its strong numerical stability by specifically considering the
spreading of non-Newtonian power-law fluids in a variable-width confined
channel-like geometry (a "Hele-Shaw cell") subject to a given mass
conservation/balance constraint. We show that this constraint can be
implemented by re-expressing it as nonlinear flux boundary conditions on the
domain's endpoints. Then, we show numerically that the scheme achieves its full
second-order accuracy in space and time. We also highlight through numerical
simulations how the proposed scheme accurately respects the mass
conservation/balance constraint.Comment: 36 pages, 9 figures, Springer book class; v2 includes improvements
and corrections; to appear as a contribution in "Applied Wave Mathematics II
Green consumer segmentation: managerial and environmental implications from the perspective of business strategies and practices
With the new millennium, environmental concern entered a new phase,
with stricter governmental regulations and incentives. Currently, within environmental
issues, there is a broader challenge to commitment with economic and social
goals. This is motivating companies and organizations to participate in transformation
processes with the aim of minimizing the negative impacts of their activities.
Within this context, new business philosophies, emerged empowering organizations
to consider sustainability issues that have come to be viewed as an innovative and
differentiating factor, providing competitive advantages (Fraj-Andres, MartinezSalinas,
& Matute-Vallejo. Journal of Business Ethics, 88,263-286, 2009; Leipziger.
The corporate responsibility code book. Greenleaf Publishing Limited, 2016;
Leipziger. The corporate responsibility code book. Greenleaf Publishing Limited,
2016). Therefore, organizations have begun incorporating these concerns in their
processes, adopting green management policies, and including green marketing
strategies in order to remain competitive (Straughan & Roberts. Journal of Consumer
Marketing, 16(6), 558-575, 1999; Rivera-Camino. European Journal of Marketing,
41, 1328-1358, 2007). From the marketing perspective, the importance of understanding
green consumer behaviour in order to develop better segmentation and
targeting strategies is highlighted. Green consumers are changing significantly.
Consumers, although with some reluctance, are moving to greener products. The
Mintel organization reported that the number of consumers buying green has tripled in recent years. Furthermore, it found that the number of consumers that never
bought green products have decreased. These results show that widespread environmental
awareness had an important role in purchasing behaviour, with more consumers
considering the environmental impact of their buying decisions and looking
for a greener alternative to their conventional purchasing options. The existing literature suggests that previous research regarding the green consumer profile has
different perspectives. The first group of researchers attempted to characterize green
consumer profile using sociodemographic variables such as age, gender, education,
income and occupation. In tum, the second group of researchers used psychographic
variables instead of sociodemographic ones (Mainieri, Barnett, Valdero, Unipan, &
Oskamp. Journal of Social Psychology, 137(2), 189-204, 1997). This chapter aims
to better explore the importance of green consumer segmentation and its implications
from a management point of view. More specifically, the aim is to analyze
which variables better characterize green consumers (sociodemographic and psychographic).
At the end, a theoretical framework is proposed to enable and support
organizations to better understand green consumer profile. It also enables managers
and marketers to target and develop better marketing strategies for these segments.info:eu-repo/semantics/publishedVersio
Throughflow and Quadratic Drag Effects on Thermal Convection in a Rotating Porous Layer
The food superstore revolution: changing times, changing research agendas in the UK
This paper considers the changing scope of research into UK food superstores over a 30-year period. Rather than catalogue changing market shares by format, we seek instead to show how change links to national policy agendas. Academic research has evolved to address the growing complexities of the social, technological, economic and political impacts of the superstore format. We exemplify this by tracing the progression of retail change in Portsmouth, Hampshire, over 30 years. We discover that academic research can conflict with the preconceptions of some public policymakers. The position is exacerbated by a progressive decline in public information – and a commensurate rise in factual data held by commercial data companies – that leaves policymakers with a choice of which data to believe. This casts a shadow over the objectivity of macro-policy as currently formulated. Concerns currently arise because the UK Competition Commission (2008 but ongoing) starts each inquiry afresh with a search for recent data. Furthermore, it has recently called for changes to retail planning – the very arena in which UK superstore research commenced
Children’s Initiatives in the Finnish Early Childhood Education Context
Pedagogical practices in early childhood education, which embrace children’s initiatives and agency, have been found to have an effect on children’s learning and competence skills. These initiatives can be seen crucial for children’s well-being and self-motivation. However, children’s initiatives are sometimes considered only as wants and that children are incapable to express meaningful initiatives in educational settings. In this chapter, we introduce children’s initiatives in their educational settings and examine the gap between children’s experiences and teachers’ observations. Children’s initiatives exist in a myriad of ways through the daily practices and processes that nourish motivation to ultimately create meanings through actions. It is essential to focus on children’s participation as it encourages and promotes agency and motivation within early childhood development.Peer reviewe
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