Conserved gravitational charges, locality and the holographic Weyl anomaly - a fresh viewpoint

Since the proposal of the AdS/CFT correspondence, made by Maldacena and Witten, there has been some controversy about the definition of conserved Noether charges associated to asymptotic isometries in asymptotically AdS spacetimes, namely, whether they form an anomalous (i.e., a nontrivial central extension) representation of the Lie algebra of the conformal group in odd bulk dimensions or not. In the present work, we shall review the derivation of these charges by using covariant phase space techniques, emphasizing the principle of locality underlying it. We shall also comment on how these issues manifest themselves in the quantum setting.Comment: revtex4 format, 3 pages, no figures. Modified version of a poster presentation made at the International Conference ''100 Years of Relativity'', held at the MASP, Sao Paulo, Brazil, in August 22nd-24th, 2005. Submitted to refereeing for publication in Conference's Proceedings volume by Braz.J.Phy

Spatial patterns in intermunicipal Danish commuting

Intermunicipal variations in in-commuting are mainly explained by variations in number of workplaces, urbanization degree and wealth, whereas variations in out- commuting are mainly determined by variations in workforce size, number of workplaces, living patterns and unemployment. This is quite satisfactory according to existing theory. However, of these explanatory factors only the number of workplaces influences the net in-commuting. But by using spatial lag structures it is shown that unemployment in neighbourhood municipalities influences net in-commuting. Finally, evidence of impact of local spatial industrial patterns on the commuting behaviour is provided, and the nature and reasons for these spatial patterns are discussed.

Organic diets and physical activity: Research experience using a rat model

Total energy expenditure or heat production is comprised of basal metabolic rate, thermic effect of food, and physical activity. Physical activity is the most variable and easily altered component of total heat production. Physical activity is influenced by a number of biological parameters i.e. diet, genetics, age, and gender. The diet components of the macro as well as micronutrients and other components (secondary metabolites) associated with a diet could contribute to the well being of the animal and cause variation in physical activity. In order to investigate physical activity as a parameter to differentiate diets based on conventional or organic grown carrots the total heat production and physical activity was measured in a rat model. The experimental diets were formulated to meet the NRC requirements for rats by mixing 40% of freeze dried carrots with an Altromin chow diet. The carrots were from a 2-year field study. The carrots were grown by three different cultivation strategies: one conventional (C) and two organic systems (OA, organic using animal manure; and OB, organic using cover crops). The diets were given to weaned female GKMol rats, in groups of five rats per diet and given their assigned diet, for approx. 2.5 months. Throughout the experimental period the rats were monitored and weighed each week. The rat’s heat production and physical activity was measured with two open-air circuit respiration chambers, and measurement was done on a group of 5 rats. In the chamber the rats were placed in individual cages. The activity was measured using both passive infrared detectors and with video recording. There was not surprisingly lower physical activity level of rats during the day. Being night-active animals, rats are usually resting during the day-time

A Test Strategy for Spurious Spatial Regression, Spatial Nonstationarity, and Spatial Cointegration

A test strategy consisting of a twofold application of a Lagrange Multiplier test is suggested as a device to reveal spatial nonstationarity and spurious spatial regeression. It is further illustrated how the test strategy can be used as a diagnostic for presence of a spatial cointegrating relationship between two variables. Using Monte Carlo simulations it is shown that the small sample behaviour of the test strategy is as desired in these cases.

Outliers in Cross-Sectional Regression

The robustness of the results coming from an econometric application depends to a great extent on the quality of the sampling information. This statement is a general rule that becomes especially relevant in a spatial context where data usually have lots of irregularities. The purpose of our paper is to examine more closely this question paying attention to one point in particular, namely outliers. The presence of outliers in the sample may be useful, for example in order to break some multicollinearity relations but they may also result in other inconsistencies. The main aspect of our work is that we resolve the discussion in a spatial context, looking closely into the behaviour shown, under several unfavourable conditions, by the most outstanding misspecification tests. For this purpose, we plan and solve a Monte Carlo simulation. The conclusions point to the fact that these statistics react in a different way to the problems posed.

Algebraic Structure of Classical Field Theory: Kinematics and Linearized Dynamics for Real Scalar Fields

We describe the elements of a novel structural approach to classical field theory, inspired by recent developments in perturbative algebraic quantum field theory. This approach is local and focuses mainly on the observables over field configurations, given by certain spaces of functionals which are studied here in depth. The analysis of such functionals is characterized by a combination of geometric, analytic and algebraic elements which (1) make our approach closer to quantum field theory, (2) allow for a rigorous analytic refinement of many computational formulae from the functional formulation of classical field theory and (3) provide a new pathway towards understanding dynamics. Particular attention will be paid to aspects related to nonlinear hyperbolic partial differential equations and their linearizations.Comment: 68 pages, no figures. Version 7: very minor corrections, DOI added. Version published (Online First) in Communications in Mathematical Physics, journal reference will be added when availabl