Expansion rate & dispersal pattern of the non-native Roesel’s bush-cricket in Sweden

Environmental change and anthropogenic activities influence species distributions. Species introductions have become increasingly common in an era of globalization and increased international trade and travel. The establishment of introduced species outside their native range and subsequent spread are of great conservation concern. Introduced species that become invasive, spread rapidly and reach high abundance, may cause the extinction of native species, disrupt ecosystem functioning and pose a threat to human health and the economy. It is therefore of great interest to understand the processes and mechanisms involved in species range expansion in order to develop effective management strategies. In this thesis I examine the influence of the landscape on species’ distribution and analyse patterns of range expansion of a non-native insect in south-central Sweden. Roesel’s bush-cricket (Metrioptera roeselii) was chosen as a model organism as its biology is well studied and its range expansion has been documented not only in Sweden but also in several other European countries. The aims of this thesis were (I) to identify landscape variables that predict the species distribution, (II) to estimate the rate of range expansion, (III) to identify the source of range expansion in south-central Sweden and to assess the dispersal pattern using population genetic data, and (IV) to analyse the influence of landscape composition and structure on population connectivity. I analysed species distribution, genetic and landscape data using a range of statistical modelling techniques in combination with geographic information systems (GIS). The results showed that the amounts of arable land, pasture and rural settlements as well as linear habitat elements are important predictors of the species’ distribution. During the last three decades, Metrioptera roeselii has expanded its range from the northern shores of the Lake Mälaren at an estimated rate of 0.3 - 3.16 km/year. The genetic diversity across the range was surprisingly high and degree of population differentiation was low to moderate likely due to frequent gene flow between populations in the centre of the species range and decreased gene flow towards the range margin. It appears the species establishes populations through infrequent long-distance and frequent short-distance dispersal (natural, human-mediated)

The True Destination of EGO is Multi-local Optimization

Efficient global optimization is a popular algorithm for the optimization of expensive multimodal black-box functions. One important reason for its popularity is its theoretical foundation of global convergence. However, as the budgets in expensive optimization are very small, the asymptotic properties only play a minor role and the algorithm sometimes comes off badly in experimental comparisons. Many alternative variants have therefore been proposed over the years. In this work, we show experimentally that the algorithm instead has its strength in a setting where multiple optima are to be identified

Entropic Priors

The method of Maximum (relative) Entropy (ME) is used to translate the information contained in the known form of the likelihood into a prior distribution for Bayesian inference. The argument is guided by intuition gained from the successful use of ME methods in statistical mechanics. For experiments that cannot be repeated the resulting "entropic prior" is formally identical with the Einstein fluctuation formula. For repeatable experiments, however, the expected value of the entropy of the likelihood turns out to be relevant information that must be included in the analysis. As an example the entropic prior for a Gaussian likelihood is calculated.Comment: Presented at MaxEnt'03, the 23d International Workshop on Bayesian Inference and Maximum Entropy Methods (August 3-8, 2003, Jackson Hole, WY, USA

Operator product expansion of the energy momentum tensor in 2D conformal field theories on manifolds with boundary

Starting from the well-known expression for the trace anomaly we derive the $T\cdot T$ operator product expansion of the energy-momentum tensor in 2D conformal theories defined in the upper halfplane $without$ making use of the additional condition of no energy-momentum flux across the boundary. The OPE turns out to be the same as in the absence of the boundary. For this result it is crucial that the trace anomaly is proportional to the Gau\ss-Bonnet density. Some relations to the $\sigma$ - model approach for open strings are discussed.Comment: 8 pages, Latex, HU Berlin-IEP-93/

Marginalization using the metric of the likelihood

Although the likelihood function is normalizeable with respect to the data there is no guarantee that the same holds with respect to the model parameters. This may lead to singularities in the expectation value integral of these parameters, especially if the prior information is not sufficient to take care of finite integral values. However, the problem may be solved by obeying the correct Riemannian metric imposed by the likelihood. This will be demonstrated for the example of the electron temperature evaluation in hydrogen plasmas.Comment: 8 pages, 2 figures, Presented at the MaxEnt 2000 conference in Gif-sur-Yvette/Pari

Is the physics within the Solar system really understood?

A collection is made of presently unexplained phenomena within our Solar system and in the universe. These phenomena are (i) the Pioneer anomaly, (ii) the flyby anomaly, (iii) the increase of the Astronomical Unit, (iv) the quadrupole and octupole anomaly, and (v) Dark Energy and (vi) Dark Matter. A new data analysis of the complete set of Pioneer data is announced in order to search for systematic effects or to confirm the unexplained acceleration. We also review the mysterious flyby anomaly where the velocities of spacecraft after Earth swing--bys are larger than expected. We emphasize the scientific aspects of this anomaly and propose systematic and continuous observations and studies at the occasion of future flybys. Further anomalies within the Solar system are the increase of the Astronomical Unit and the quadrupole and octupole anomaly. We briefly mention Dark Matter and Dark Energy since in some cases a relation between them and the Solar system anomalies have been speculated.Comment: 22 pages, 3 figures, submitted for the proceedings of the 359th WE-Heraeus Seminar on "Lasers, Clocks, and Drag-Free: Technologies for Future Exploration in Space and Tests of Gravity

Chronological relationship between antisocial personality disorder and alcohol dependence

Personality disorders, and particularly antisocial personality disorder (ASPD), frequently co-occur with alcohol dependence. ASPD is considered to be an important cofactor in the pathogenesis and clinical course of alcohol dependence. The chronological relationship between the onset of symptoms of ASPD and alcohol-dependence characteristics has not yet been studied in great detail and the role of ASID in classification schemes of alcohol dependence as suggested by Cloninger and Schuckit has yet to be determined. We studied 55 alcohol-dependent patients to assess the prevalence and age at manifestation of ASPD, conduct disorder characteristics as well as alcohol dependence by employing the Semi-Structured Assessment for the Genetics of Alcoholism and the Structured Clinical Interview for DSM-IIIR. Results indicate that the onset of ASPD characteristics precede that of alcohol dependence by some 4 years. This finding suggests that in patients with ASPD, alcohol dependence might be a secondary syndrome as suggested by previous research. Copyright (C) 2002 S. Karger AG, Basel

The Problem of Legitimacy in the European Polity. Is Democratization the Answer?

The authors discuss potential sources of legitimacy of the EU, i. e. of the normative bindingness of its decisions. After rejecting the views that such legitimacy is either not needed, not feasible, or provided for already, they focus upon the corrosive impact of the EU upon democratic legitimacy within member states. Brussels-based 'governance' is essentially uncontested and can hardly provide for the legitimacy that results from the interplay between government and opposition within nation states. The problem boils down to achieving legitimacy in the absence of the political community of a 'demos'. The paper outlines a solution to this problem that relies on the apparently oxymoronic model of a 'republican empire' - a political community, that is, which is held together not by the bonds of some presumed sameness, but, to the contrary, by the shared contractual recognition of the dissimilarity of its constituent parts from which legitimacy can flow.democracy; legitimacy; diversity/homogeneity; governance; democratization

Modelling the distribution of the invasive Roesel’s bushcricket (Metrioptera roeselii) in a fragmented landscape

The development of conservation strategies to mitigate the impact of invasive species requires knowledge of the species ecology and distribution. This is, however, often lacking as collecting biological data may be both time-consuming and resource intensive. Species distribution models can offer a solution to this dilemma by analysing the species-environment relationship with help of Geographic information systems (GIS). In this study, we model the distribution of the non-native bush-cricket Metrioptera roeselii in the agricultural landscape in mid-Sweden where the species has been rapidly expanding in its range since the 1990s. We extract ecologically relevant landscape variables from Swedish CORINE land-cover maps and use species presence-absence data from large-scale surveys to construct a species distribution model (SDM). The aim of the study is to increase the knowledge of the species range expansion pattern by examining how its distribution is affected by landscape composition and structure, and to evaluate SDM performance at two different spatial scales. We found that models including data on a scale of 1 × 1 km were able to explain more of the variation in species distribution than those on the local scale (10 m buffer on each side of surveyed road). The amount of grassland in the landscape, estimated from the area of arable land, pasture and rural settlements, was a good predictor of the presence of the species on both scales. The measurements of landscape structure – linear elements and fragmentation - gave ambivalent results which differed from previous small scaled studies on species dispersal behaviour and occupancy patterns. The models had good predictive ability and showed that areas dominated by agricultural fields and their associated grassland edges have a high probability being colonised by the species. Our study identified important landscape variables that explain the distribution of M. roeselii in Mid-Sweden that may also be important to other range expanding orthopteran species. This work will serve as a foundation for future analyses of species spread and ecological processes during range expansion