1,373 research outputs found
Boosting business with data analysis
__Abstract__
Pretty much every modern organisation collects a mountain of data
on a daily basis as it goes about its business. But all that data is of
little real value unless it is properly analysed and used to anticipate
client behaviour and needs
Mathematical models for vulnerable plaques
A plaque is an accumulation and swelling in the artery walls and typically consists of cells, cell debris, lipids, calcium deposits and fibrous connective tissue. A person is likely to have many plaques inside his/her body even if they are healthy. However plaques may become "vulnerable", "high-risk" or "thrombosis-prone" if the person engages in a high-fat diet and does not exercise regularly.
In this study group, we proposed two mathematical models to describe plaque growth and rupture.
The first model is a mechanical one that approximately treats the plaque as an inflating elastic balloon. In this model, the pressure inside the core increases and then decreases suggesting that plaque stabilization and prevention of rupture is possible.
The second model is a biochemical one that focuses on the role of MMPs in degrading the fibrous plaque cap. The cap stress, MMP concentration, plaque volume and cap thickness are coupled together in a system of phenomenological equations. The equations always predict an eventual rupture since the volume, stresses and MMP concentrations generally grow without bound. The main weakness of the model is that many of the important parameters that control the behavior of the plaque are unknown.
The two simple models suggested by this group could serve as a springboard for more realistic theoretical studies. But most importantly, we hope they will motivate more experimental work to quantify some of the important mechanical and biochemical properties of vulnerable plaques
Relationships between insect predator populations and their prey, Thrips tabaci, in onion fields grown in large-scale and small-scale cropping systems
Anisotropic diffusion in continuum relaxation of stepped crystal surfaces
We study the continuum limit in 2+1 dimensions of nanoscale anisotropic
diffusion processes on crystal surfaces relaxing to become flat below
roughening. Our main result is a continuum law for the surface flux in terms of
a new continuum-scale tensor mobility. The starting point is the Burton,
Cabrera and Frank (BCF) theory, which offers a discrete scheme for atomic steps
whose motion drives surface evolution. Our derivation is based on the
separation of local space variables into fast and slow. The model includes: (i)
anisotropic diffusion of adsorbed atoms (adatoms) on terraces separating steps;
(ii) diffusion of atoms along step edges; and (iii) attachment-detachment of
atoms at step edges. We derive a parabolic fourth-order, fully nonlinear
partial differential equation (PDE) for the continuum surface height profile.
An ingredient of this PDE is the surface mobility for the adatom flux, which is
a nontrivial extension of the tensor mobility for isotropic terrace diffusion
derived previously by Margetis and Kohn. Approximate, separable solutions of
the PDE are discussed.Comment: 14 pages, 1 figur
Maser Observations Of Westerlund 1 And Comprehensive Considerations On Maser Properties Of Red Supergiants Associated With Massive Clusters
published_or_final_versio
Teachers, policymakers and project learning: The questionable use of ‘hard’ and ‘soft’ policy instruments to influence the implementation of curriculum reform in Hong Kong
Following the return of Hong Kong to Chinese sovereignty in 1997, the government of the Hong Kong Special Administrative Region developed wide-ranging curriculum reforms, including project learning. A recent survey has indicated that over 80% of Hong Kong primary and secondary schools have adopted project learning as a curriculum task. Such an outcome is hard to reconcile both with the culture of Hong Kong schools and the generally bleak picture that pervades the literature on educational change.
In seeking an explanation for this apparent success we focus attention on the policy instruments that were used by government agencies to facilitate the process of implementation. Our analysis revealed that teachers were caught in a pincer movement that involved voluntary activities promoting project learning and coercive measures that monitored and evaluated successful implementation. Teachers’ views of these policy instruments differed markedly from those of policymakers. This confluence of mixed approaches, while apparently successful, is also shown to be problematic. Finally, the paper is located in a theoretical framework with its origins in recent policy theory that to date has not been applied to educational contexts
Employee Perceptions of Individual and Organizational Commitment to the Green Movement and Their Perceived Impacts Between Male and Female Subjects
In this research, we find support for a proposed set of linkages among employee perceptions of organizational green orientation, individual green orientation, and impacts of the green movement on organizational performance among male and female subjects. We report significant MANOVA results indicating differences between male and female subjects, with female subjects showing a general pattern of higher alignment with the green movement. Moreover, our examination of relationships among the scales used in this study indicates that the patterns are not consistent for males and females. Females consistently report more and more positive relationships. We discuss differences, consider possible causes, and suggest future research
- …