6,509 research outputs found
A Cartan-Hadamard type result for relatively hyperbolic groups
In this article, we prove that if a finitely presented group has an
asymptotic cone which is tree-graded with respect to a precise set of pieces
then it is relatively hyperbolic. This answers a question of M. Sapir.Comment: 33 pages, 2 figure
Recommended from our members
Emerging Translational Opportunities in Comparative Oncology With Companion Canine Cancers: Radiation Oncology.
It is estimated that more than 6 million pet dogs are diagnosed with cancer annually in the USA. Both primary care and specialist veterinarians are frequently called upon to provide clinical care that improves the quality and/or quantity of life for affected animals. Because these cancers develop spontaneously in animals that often share the same environment as their owners, have intact immune systems and are of similar size to humans, and because the diagnostic tests and treatments for these cancers are similar to those used for management of human cancers, canine cancer provides an opportunity for research that simultaneously helps improve both canine and human health care. This is especially true in the field of radiation oncology, for which there is a rich and continually evolving history of learning from the careful study of pet dogs undergoing various forms of radiotherapy. The purpose of this review article is to inform readers of the potential utility and limitations of using dogs in that manner; the peer-reviewed literature will be critically reviewed, and current research efforts will be discussed. The article concludes with a look toward promising future directions and applications of this pet dog "model.
THEME OVERVIEW: FUNDAMENTAL FORCES AFFECTING AGRIBUSINESS INDUSTRIES
Agribusiness, Market Forces, Structural Change, Porterâs Five Forces, Community/Rural/Urban Development, Q13, L10, L22, M22, L80,
MARKET FORCES AND CHANGES IN THE PLANT INPUT SUPPLY INDUSTRY
Agribusiness, Input Supply Industry, Fertilizer, Plant Nutrients, Seed, Capital, Market Forces, Structural Change, Porterâs Five Forces, Agribusiness, Q13, L10, L22, M22, L80,
Recommended from our members
A dimensionality reduction method to select the most representative daylight illuminance distributions
One challenge when evaluating daylight distribution is dealing with the large amount of temporal and spatial data, visualisations and variability in illuminances that are assessed in buildings. Using a dimensionality reduction method based on principal component analysis, we identified the most representative annual daylight distributions. We modelled a rectangular room containing an analysis grid of 3200 illuminance sensor points and simulated 3285 different temporal daylight conditions using an annual occupancy schedule ranging from 08:00 to 17:00 with one-hour sampling intervals in two locations: Singapore and Oakland, California. Our approach explained 98 % of the illuminance variability with three daylight distributions in Singapore, and 92 % using six in Oakland, California. Our dimensionality reduction strategy was also generalised using a complex building geometry showing the utility of the method. We think this approach can be used to provide a more efficient and reliable method to analyse daylight performance in building practice
Transfer Length of Strands in Prestressed Concrete Piles
A top bar effect has been identified in prestressed concrete piles. The effect that this top bar effect has on the development of the prestressing strand is investigated. Strand transfer length is found to be proportional to the observed end slip. While the average transfer length of all strands in a section may satisfy the assumptions inherent in the ACI transfer length equation, due to the top bar effect, top-cast strand transfer lengths are considerably in excess of the ACI-calculated value. The flexural behavior of the pile, accounting for varying transfer lengths through its section, is investigated. Finally, recommendations for in-plant testing and acceptance criteria for prestressed strand bond quality are proposed
Asset Prices, Credit Growth, Monetary and Other Policies: An Australian Case Study
The long-running debate about the role of monetary policy in responding to rising asset prices has received renewed attention in the wake of the global financial crisis.This paper contributes to this debate by describing the Australian experience of a cycle in house prices and credit from 2002 to 2004, and discussing the role played by various policies during this episode. In particular, it focuses on the efforts by the Reserve Bank of Australia to draw attention to the risks associated with large, ongoing increases in housing prices and household borrowing.asset prices; credit growth; lending standards; monetary policy; regulatory policy
Empirical analysis of vegetation dynamics and the possibility of a catastrophic desertification transition
The process of desertification in the semi-arid climatic zone is considered
by many as a catastrophic regime shift, since the positive feedback of
vegetation density on growth rates yields a system that admits alternative
steady states. Some support to this idea comes from the analysis of static
patterns, where peaks of the vegetation density histogram were associated with
these alternative states. Here we present a large-scale empirical study of
vegetation dynamics, aimed at identifying and quantifying directly the effects
of positive feedback. To do that, we have analyzed vegetation density across
of the African Sahel region, with spatial
resolution of meters, using three consecutive snapshots. The
results are mixed. The local vegetation density (measured at a single pixel)
moves towards the average of the corresponding rainfall line, indicating a
purely negative feedback. On the other hand, the chance of spatial clusters (of
many "green" pixels) to expand in the next census is growing with their size,
suggesting some positive feedback. We show that these apparently contradicting
results emerge naturally in a model with positive feedback and strong
demographic stochasticity, a model that allows for a catastrophic shift only in
a certain range of parameters. Static patterns, like the double peak in the
histogram of vegetation density, are shown to vary between censuses, with no
apparent correlation with the actual dynamical features
- âŠ