Magnetic orientation of the Common Toad: establishing an arena approach for adult anurans

<p>Abstract</p> <p>Background</p> <p>Magnetic orientation is a taxonomically widespread phenomenon in the animal kingdom, but has been little studied in anuran amphibians. We collected Common Toads (<it>Bufo bufo</it>) during their migration towards their spawning pond and tested them shortly after displacement for possible magnetic orientation in arena experiments. Animals were tested in two different set-ups, in the geomagnetic field and in a reversed magnetic field. To the best of our knowledge, this is the first study testing orientation of adult anurans with a controlled magnetic field of a known strength and alignment.</p> <p>Results</p> <p>After displacement, toads oriented themselves unimodally under the geomagnetic field, following their former migration direction (d-axis). When the magnetic field was reversed, the distribution of bearings changed from a unimodal to a bimodal pattern, but still along the d-axis. The clustering of bearings was only significant after the toads reached the outer circle, 60.5 cm from their starting point. At a virtual inner circle (diameter 39 cm) and at the start of the experiment, orientation of toads did not show any significant pattern.</p> <p>Conclusions</p> <p>The experimental set-up used in our study is suitable to test orientation behaviour of the Common Toad. We speculate that toads had not enough time to relocate their position on an internal map. Hence, they followed their former migration direction. Bimodality in orientation when exposed to the reversed magnetic field could be the result of a cue conflict, between magnetic and possibly celestial cues. For maintaining their migration direction toads use, at least partly, the geomagnetic field as a reference system.</p

Towards operational measures of computer security

Ideally, a measure of the security of a system should capture quantitatively the intuitive notion of ‘the ability of the system to resist attack’. That is, it should be operational, reflecting the degree to which the system can be expected to remain free of security breaches under particular conditions of operation (including attack). Instead, current security levels at best merely reflect the extensiveness of safeguards introduced during the design and development of a system. Whilst we might expect a system developed to a higher level than another to exhibit ‘more secure behaviour’ in operation, this cannot be guaranteed; more particularly, we cannot infer what the actual security behaviour will be from knowledge of such a level. In the paper we discuss similarities between reliability and security with the intention of working towards measures of ‘operational security’ similar to those that we have for reliability of systems. Very informally, these measures could involve expressions such as the rate of occurrence of security breaches (cf rate of occurrence of failures in reliability), or the probability that a specified ‘mission’ can be accomplished without a security breach (cf reliability function). This new approach is based on the analogy between system failure and security breach. A number of other analogies to support this view are introduced. We examine this duality critically, and have identified a number of important open questions that need to be answered before this quantitative approach can be taken further. The work described here is therefore somewhat tentative, and one of our major intentions is to invite discussion about the plausibility and feasibility of this new approach

Evaluating On-line Model Checking in UPPAAL-SMC using a Laser Tracheotomy Case Study

On-line model checking is a variant of model checking that evaluates properties of a system concurrently while deployed, which allows overcoming limitations of inaccurate system models. In this paper we conduct a laser tracheotomy case study to evaluate the feasibility of using the statistical model checker UPPAAL-SMC for on-line model checking in a medical application. Development of automatic on-line model checking relies on the precision of the prediction and real-time capabilities as real-time requirements must be met. We evaluate the case study with regards to these qualities and our results show that using UPPAAL-SMC in an on-line model checking context is practical: relative prediction errors were only 2% on average and guarantees could be established within reasonable time during our experiments

Das Leben protestantischer Pastoren in Deutschland vom Ende des 17. Jahrhunderts bis zur Mitte des 19. Jahrhunderts

Nicht angegebe

Demography and spatial activity of fire salamanders, Salamandra salamandra (Linnaeus, 1758), in two contrasting habitats in the Vienna Woods

Understanding population dynamics is vital in amphibian conservation. To compare demography and movements, we conducted a capture-recapture study over three spring seasons in two populations of Salamandra salamandra in the Vienna Woods. The study sites differ in topography, vegetation, and the type of breeding waters. Population density in a beech forest traversed by a stream was more than twice as high as in an oak-hornbeam forest with temporary pools. Movement distances were on average higher at the latter site whereas home range estimates were similar for both sites. The sexes did not differ significantly in the observed movement patterns at either site. Annual apparent survival was mostly high (~0.85), but the estimate for females from the low-density site was lower (~0.60), indicating a higher rate of emigration or mortality

Estudo de viabilidade econômica e da implantação de condomínio horizontal de lotes para fins residenciais no município de Venâncio Aires

O condomínio horizontal de lotes consiste em um formato de habitação diferente das demais existentes nas cidades com crescimento urbano acelerado, e suas principais características estão relacionadas ao conforto e a segurança. Este trabalho tem como objetivo apresentar o estudo de viabilidade econômica através de levantamento de despesas necessárias para a implantação e da simulação de cenários para a venda dos lotes, na cidade de Venâncio Aires, e ainda demonstrar os procedimentos para que este modelo de projeto possa ser implantado. Inicialmente realizou-se o projeto urbanístico e o pré-dimensionamento da rede de água, esgoto, elétrica e pluvial. Em seguida, foi realizado o cálculo estimado de despesas que ocorrerão durante a construção do empreendimento, o que resultou em um valor total de R$9.252.752,32, referentes à construção das edificações e áreas de uso recreativo, da infraestrutura e demais custos de operação. Após essa etapa foi desenvolvido um cronograma físico-financeiro para identificar o valor total de despesas geradas a cada mês, durante o período de construção e, por fim, foi realizado o estudo de viabilidade econômica para este empreendimento, utilizando simulações para a venda dos lotes. A partir das simulações que consideraram diferentes cenários para a venda dos lotes, foi possível concluir que a instalação deste tipo de empreendimento em Venâncio Aires é viável. Concluiu-se, também, que o valor mínimo praticável, para a venda dos imóveis deverá ser de R$ 135.000,00, que possibilita uma lucratividade superior a 6,45 %

08302 Abstracts Collection -- Countering Insider Threats

From July 20 to July 25, 2008, the Dagstuhl Seminar 08302 ``Countering Insider Threats \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Geoquímica e Isotópos de Nd de Rochas Metavulcânicas da Antiforme Capané, Complexo Metamórfico Porongos, RS

The Capané Antiform, located in the northern part of the Neoproterozoic Porongos Metamorphic Complex (RS), is composed of a supracrustal sequence metamorphosed under greenschist (eastern flank) to amphibolite (western flank) facies. Four groups of rocks were recognized. Groups 1 and 2 are constituted of felsic and mafic rocks from the central and western part of the antiform, respectively. They show high LREE and LILE and low HREE and HFSE. The εNd (t) varies from strongly negative (-20) in felsic rocks to moderately negative (-6 to -11) in mafic rocks, with Nd TDM ages that varies from Paleoproterozoic to Mesoproterozoic. The Group 3 consists of metarhyolites from the eastern flank and is geochemically similar to former groups, but shows differences in Nd isotope composition. The εNd(t) is slightly negative (-2 to -4) and the model ages are restricted to the Mesoproterozoic. Group 4, constituted of metabasalts, shows chemical similarities with OIB-MORB and has juvenile isotope signature. The first three groups were interpreted as evolved from a magmatic arc, related probably to the collision of the São Gabriel block with the Encantadas microcontinent during the Neoproterozoic. The Nd differences observed were considered as a result of more or less interaction between mantle and crust components and, particularly, the characteristics observed in the Group 3 can point out a correlation with the syn-tangential granitoids from the eastern part of the Dom Feliciano Belt. The metabasalts of the group 4 were correlated to the antiform's previously described ophiolite remains.The Capané Antiform, located in the northern part of the Neoproterozoic Porongos Metamorphic Complex (RS), is composed of a supracrustal sequence metamorphosed under greenschist (eastern flank) to amphibolite (western flank) facies. Four groups of rocks were recognized. Groups 1 and 2 are constituted of felsic and mafic rocks from the central and western part of the antiform, respectively. They show high LREE and LILE and low HREE and HFSE. The εNd (t) varies from strongly negative (-20) in felsic rocks to moderately negative (-6 to -11) in mafic rocks, with Nd TDM ages that varies from Paleoproterozoic to Mesoproterozoic. The Group 3 consists of metarhyolites from the eastern flank and is geochemically similar to former groups, but shows differences in Nd isotope composition. The εNd(t) is slightly negative (-2 to -4) and the model ages are restricted to the Mesoproterozoic. Group 4, constituted of metabasalts, shows chemical similarities with OIB-MORB and has juvenile isotope signature. The first three groups were interpreted as evolved from a magmatic arc, related probably to the collision of the São Gabriel block with the Encantadas microcontinent during the Neoproterozoic. The Nd differences observed were considered as a result of more or less interaction between mantle and crust components and, particularly, the characteristics observed in the Group 3 can point out a correlation with the syn-tangential granitoids from the eastern part of the Dom Feliciano Belt. The metabasalts of the group 4 were correlated to the antiform's previously described ophiolite remains

A Simple Attack on Some Clock-Controlled Generators

We present a new approach to edit distance attacks on certain clock-controlled generators, which applies basic concepts of Graph Theory to simplify the search trees of the original attacks in such a way that only the most promising branches are analyzed. In particular, the proposed improvement is based on cut sets defined on some graphs so that certain shortest paths provide the edit distances. The strongest aspects of the proposal are that the obtained results from the attack are absolutely deterministic, and that many inconsistent initial states of the target registers are recognized beforehand and avoided during search