Spinorial Characterization of Surfaces into 3-dimensional homogeneous Manifolds

We give a spinorial characterization of isometrically immersed surfaces into 3-dimensional homogeneous manifolds with 4-dimensional isometry group in terms of the existence of a particular spinor, called generalized Killing spinor. This generalizes results by T. Friedrich for $\R^3$ and B. Morel for \Ss^3 and \HH^3. The main argument is the interpretation of the energy-momentum tensor of a genralized Killing spinor as the second fondamental form up to a tensor depending on the structure of the ambient spaceComment: 35 page

A simple method for detecting chaos in nature

Chaos, or exponential sensitivity to small perturbations, appears everywhere in nature. Moreover, chaos is predicted to play diverse functional roles in living systems. A method for detecting chaos from empirical measurements should therefore be a key component of the biologist's toolkit. But, classic chaos-detection tools are highly sensitive to measurement noise and break down for common edge cases, making it difficult to detect chaos in domains, like biology, where measurements are noisy. However, newer tools promise to overcome these limitations. Here, we combine several such tools into an automated processing pipeline, and show that our pipeline can detect the presence (or absence) of chaos in noisy recordings, even for difficult edge cases. As a first-pass application of our pipeline, we show that heart rate variability is not chaotic as some have proposed, and instead reflects a stochastic process in both health and disease. Our tool is easy-to-use and freely available

The Economics of Terrorism and Counter-Terrorism: A Survey (Part I)

This survey provides an in-depth analysis of existing research on the economic analysis of terrorism and counter-terrorist measures. First the existing evidence on the causes of terrorism is analyzed, then we consider the evidence of the consequences of terrorism and we demonstrate why it is important to regarding of the issue of counter-terrorism policy. Moreover the survey presents the existing knowledge on the interrelation between the economy and the issue of security and it incorporates analysis the level of knowledge about the causal chains between security and the economy. Also it focuses on perspective and methodologies from the discipline of economics but also refers to research from related disciplines (sociology, political science). It also assembles the knowledge on the impact of terrorism on the economy as reflected in macro-economic variables and its impact on specific sectors. Furthermore it assesses how potential an actual terrorist event determine consumer and producer behaviour, public policy, as well as terrorist responses to these policies. Finally a European perspective on the terrorism security annexes is discussed and here we analyze the causes of terrorism in Europe.risk, insecurity, survey, terrorism, counter-terrorism, security economics

The Economics of Terrorism and Counter-Terrorism: A Survey (Part I)

This survey provides an in-depth analysis of existing research on the economic analysis of terrorism and counter-terrorist measures. First the existing evidence on the causes of terrorism is analyzed, then we consider the evidence of the consequences of terrorism and we demonstrate why it is important to regarding of the issue of counter-terrorism policy. Moreover the survey presents the existing knowledge on the interrelation between the economy and the issue of security and it incorporates analysis the level of knowledge about the causal chains between security and the economy. Also it focuses on perspective and methodologies from the discipline of economics but also refers to research from related disciplines (sociology, political science). It also assembles the knowledge on the impact of terrorism on the economy as reflected in macro-economic variables and its impact on specific sectors. Furthermore it assesses how potential an actual terrorist event determine consumer and producer behaviour, public policy, as well as terrorist responses to these policies. Finally a European perspective on the terrorism security annexes is discussed and here we analyze the causes of terrorism in Europe.risk, insecurity, survey, terrorism, counter-terrorism, security economics