Naturalness

About: Naturalness is a research topic. Over the lifetime, 1305 publications have been published within this topic receiving 31737 citations.

Changes in landscape naturalness derived from a historical land register—a case study from NE Germany

Abstract: The naturalness of landscapes and its assessment is a major issue in landscape management and nature conservation (Ridder 2007a; Verhoog et al. 2007). Additionally, natural sites serve as a reference for ecosystem restoration and landscape planning (Siipi 2004; SER 2004; van Andel and Aronson 2006; Zerbe et al. 2009). However, it is often not clearly specified what naturalness is or could be (Ridder 2007b) with regard to time scale and human impact. Definitions and methods of assessment have been introduced and discussed by various authors (see for example Peterken 1996; Machado 2004; Kowarik 2006; Timmermann et al. 2006a; Ridder 2007b; Walentowski and Winter 2007; Reif and Walentowski 2008). The definition of a starting point (‘‘natural state‘‘) with which ecosystems or landscapes in a given condition are to be compared turns out to be a crucial point. In most of these studies vegetation is identified as a measure for naturalness, as vegetation reflects anthropogenically changed abiotic and biotic site conditions and can be used as an indicator for landscape properties (Ellenberg 1996). It also offers important criteria for nature conservation assessments (Mueller-Dombois and Ellenberg 1974; Maarel 2005). In the past decades, numerous methods have been applied to describe and reconstruct historical landscapes (see e.g. surveys by Egan and Howell 2001). One of the most important sources for historical landscape ecology are historical maps with which ancient landscapes can be reconstructed. In Central Europe, detailed mapping reaches back for about several hundred years (Küchler and Zonneveld 1988). Although there exist a great number of investigations and elaborate methodology with regard to the analysis of land-use and land-cover change in Central Europe (e.g. Bastian and Bernhardt 1993; Hobbs 1994; Ihse 1996; Skĺnes 1996; Pärtel et al. 1999; Zerbe and Brande 2003; Coppin et al. 2004; Zerbe 2004; Bender et al. 2005; Wanja et al. 2007), a detailed reconstruction of abiotic site conditions in historical landscapes such as, e.g., soil water and nutrient conditions has hardly been achieved. A particular situation for historical landscape reconstruction is given in NE Germany with the Swedish Register Maps which have been drawn around 1700 AD on a scale of about 1:8,300. These historical maps, including comprehensive annotations in textbooks, offer detailed information about settlements, land use, inhabitants, and the property state of land as well as vegetation, abiotic site conditions, and yield. Thus, our study aims to provide a reconstruction of the landscape 300 years ago and its abiotic site conditions, in order to assess the naturalness of F. Jansen (&) S. Zerbe M. Succow Institute of Botany and Landscape Ecology, Ernst-Moritz-Arndt-University, Grimmer Str. 88, 17487 Greifswald, Germany e-mail: jansen@uni-greifswald.de

Comments on the hierarchy problem in effective theories

Abstract: We discuss aspects of the hierarchy problem in effective theories with light scalars and a large, physical ultraviolet (UV) cutoff We make two main points: (1) The (naive) fine-tuning observed in an effective theory does not automatically imply that the UV completion is fine tuned Instead, it gives a type of upper bound on the severity of the actual tuning in the UV completion; the actual tuning can be less severe than the naive tuning or even non-existent (2) Within an effective theory, there appear to be two types of parameter relations that can alleviate the sensitivity of the scalar mass to the cutoff — relationships among dimensionless couplings or relationships among dimensionful parameters Supersymmetric models provide symmetry-motivated examples of the former, while scale-invariant models give symmetry-motivated examples of the latter

Vacuum Nucleon Loops and Naturalness.

Abstract: Phenomenological studies support the applicability of naturalness and naive dimensional analysis to hadronic effective lagrangians for nuclei. However, one-baryon-loop vacuum contributions in renormalizable models give rise to unnatural coefficients, which indicates that the quantum vacuum is not described adequately. The effective lagrangian framework accommodates a more general characterization of vacuum contributions without reference to a Dirac sea of nucleons.

Which fine-tuning arguments are fine?

Abstract: The argument from naturalness is widely employed in contemporary quantum field theory. Essentially a formalized aesthetic criterion, it received a meaning in the debate on the Higgs mechanism, which goes beyond aesthetics. We follow the history of technical definitions of fine tuning at the scale of electroweak symmetry breaking. It is argued that they give rise to a special interpretation of probability, which we call Gedankenfrequency. By extension of its original meaning, the argument from naturalness is used to compare different models beyond the Standard Model. We show that in this case naturalness cannot be defined objectively. Rather, it functions as socio-historical heuristics in particle physics and it contributes to the advent of a probabilistic version of Popper's falsificationism.

Problems of naturalness: Some lessons from string theory

Abstract: We consider some questions of naturalness which arise when one considers conventional field theories in the presence of gravitation: the problem of global symmetries, the strong CP problem, and the cosmological constant problem. Using string theory as a model, we argue that it is reasonable to postulate weakly broken global discrete symmetries. We review the arguments that gravity is likely to spoil the Peccei-Quinn solution of the strong CP problem, and update earlier analyses showing that discrete symmetries can lead to axions with suitable properties. Even if there are not suitable axions, we note that string theory is a theory in which CP is spontaneously broken and $\theta$ in principle calculable. $\theta$ thus might turn out to be small along lines suggested some time ago by Nelson and by Barr.