Steerable filters generated with the hypercomplex dual-tree wavelet transform

The use of wavelets in the image processing domain is still in its infancy, and largely associated with image compression. With the advent of the dual-tree hypercomplex wavelet transform (DHWT) and its improved shift invariance and directional selectivity, applications in other areas of image processing are more conceivable. This paper discusses the problems and solutions in developing the DHWT and its inverse. It also offers a practical implementation of the algorithms involved. The aim of this work is to apply the DHWT in machine vision. Tentative work on a possible new way of feature extraction is presented. The paper shows that 2-D hypercomplex basis wavelets can be used to generate steerable filters which allow rotation as well as translation.</p

A machine vision extension for the Ruby programming language

Dynamically typed scripting languages have become popular in recent years. Although interpreted languages allow for substantial reduction of software development time, they are often rejected due to performance concerns. In this paper we present an extension for the programming language Ruby, called HornetsEye, which facilitates the development of real-time machine vision algorithms within Ruby. Apart from providing integration of crucial libraries for input and output, HornetsEye provides fast native implementations (compiled code) for a generic set of array operators. Different array operators were compared with equivalent implementations in C++. Not only was it possible to achieve comparable real-time performance, but also to exceed the efficiency of the C++ implementation in several cases. Implementations of several algorithms were given to demonstrate how the array operators can be used to create concise implementations.</p

Copepod reaction to odor stimuli influenced by cestode infection

The cestode Schistocephalus solidus uses copepods as first and sticklebacks as second intermediate hosts. For transmission, an infected copepod has to be preyed upon by a stickleback. We used copepods of the species Macrocy albidus to test whether infected and uninfected copepods differ in their reaction to two kind of simultaneously presented odors: odors of sticklebacks and odors of sticklebacks and conspecificz. By giving this choice, we attempted to force the copepods to make a trade-off between the benefit of risk dilution and possible predator confusion and the costs of food competition and other disadvantages induced by conspecifics. Within 1-8 h after last feeding, uninfected copepods clearly preferred the odors of conspeciflcs under the chemically simulated threat of predation. This was in contrast to the infected copepods, who tended to avoid the odor of conspecifics. When the time between experiment and last feeding varied, infected copepods showed an increas preference for fish water only (or avoided conspecthcs) with increasing hunger level This suggests that S. solidus benefits from hunger-induced behavioral changes of its copepod host by influencing its microhabitat selection. The same effect could be found in both sexes; however, it was significantly more pronounced in male than in female copepods. We propose several hypotheses that could explain the difference between the sexes in their infection-dependent microhabitat selectio

The separate and combined effects of MHC genotype, parasite clone, and host gender on the course of malaria in mice

BACKGROUND: The link between host MHC (major histocompatibility complex) genotype and malaria is largely based on correlative data with little or no experimental control of potential confounding factors. We used an experimental mouse model to test for main effects of MHC-haplotypes, MHC heterozygosity, and MHC × parasite clone interactions. We experimentally infected MHC-congenic mice (F2 segregants, homo- and heterozygotes, males and females) with one of two clones of Plasmodium chabaudi and recorded disease progression. RESULTS: We found that MHC haplotype and parasite clone each have a significant influence on the course of the disease, but there was no significant host genotype by parasite genotype interaction. We found no evidence for overdominance nor any other sort of heterozygote advantage or disadvantage. CONCLUSION: When tested under experimental conditions, variation in the MHC can significantly influence the course of malaria. However, MHC heterozygote advantage through overdominance or dominance of resistance cannot be assumed in the case of single-strain infections. Future studies might focus on the interaction between MHC heterozygosity and multiple-clone infections

Slow releasing artificial tears for contact lens wearers with dry eyes

Thirteen contact lens patients with an objective and/or subjective diagnosis of dry eye were given a non-medicated (hydroxypropyl cellulose) slow releasing artificial tear (SR-AT). After two weeks of daily use, a majority of the patients reported positive results, including two patients with giant papillary conjunctivitis (GPC) and one with nocturnal lagophthalmos. It appears that this ocular insert may be beneficial for diagnosing the dry eye problems of contact lens wearers as well as non-contact lens wearers that are due to insufficient hydration and lubrication at the conjunctival/corneal and contact lens interface

Virtual Campus – Trends and Perspectives in Germany

In the last few years in Germany virtual campus initiatives have been funded considerably. In our paper we will give a review of comments and recommendations of the advisory boards in higher education policy and of the various funding schemes on the level of the federal states and the federal government. An analysis of the current program „New Media in Education” indicates trends of possible developments as well as hindrances in the virtualization of higher educationIn: A.J. Kallenberg and M.J.J.M. van de Ven (Eds), 2002, The New Educational Benefits of ICT in Higher Education: Proceedings. Rotterdam: Erasmus Plus BV, OECR ISBN 90-9016127-

Retrieving and recontextualising VET theory

To what extent can we speak of theory specific to vocational education and training (VET) and what is its relevance today? This Special Issue 19 of bwp@ aims to (re)ignite academic discourse on VET theory, retrieving earlier theorisation specific to this field, mainly from Germany, Austria, and Switzerland (the DACH countries) and connecting it both with international perspectives and contemporary debates. We invite papers in English or German that engage with these debates. From an international perspective, the DACH countries are extraordinary both in their proposition of theories of VET sui generis and especially in their influence on the field of policy and practice. By contrast, for example in English-speaking countries, influential theories that address the question of vocational study, whilst drawing extensively on philosophical and social science concepts, developed largely in opposition to policy and practices that positioned vocational learning as an inferior pathway and narrowed its educational scope. The dual apprenticeship model has been widely imitated internationally but without regard to the social partnerships, labour markets and education workforce developed in Germany, and the theories that shaped this system are neither translated nor widely discussed in other languages. While there are several approaches to VET theory, the core of all these approaches is a framework of normative goals of education, a characterisation of how these goals can be reached through vocational education in particular and the formulation of (education) policy implications that are necessary for successful implementation. For example, Kerschensteiner (1901, 1966/1904) in his emphasis on civic virtues as a central aim of education, drew attention to the possibility of attaining such virtues through work, but acknowledged the necessity of a foundation in general education. In contrast, post-war critical approaches, which regularly draw on critical theory (see Habermas 1968; Horkheimer & Adorno 1947), and can be dated to the 1960s and 1970s, identify autonomy and emancipation as central objectives of education (e.g. Lempert 1971; Blankertz 1974, 1979, 1982). The main challenge of VET theory was to explain how these goals also can be reached through vocational education. Blankertz’s answer lay in emphasizing the role of the VET school in widening and deepening knowledge associated with the workspace. The value of these approaches for contemporary VET is dependent on their adaptation to contemporary problems that VET and society are experiencing: migration and integration; climate change and resource consumption, digitisation and globalisation. The tertiarisation of both the economy and of education, as the service sector employs a greater proportion of the population and a growing number of young people enter higher education, even in Germany, also calls into question the relevance of established VET theories. As the structures and forms of organisation that have sustained VET since the 1970s have given way to new social formations and new forms of precarity, the relevance of theories developed during the long period of post-war growth is called into question. Correspondingly, whether a critical standpoint can still be clearly located after the “fall of metaphysics” (Adorno 1998/1965) has also been deemed as questionable (cf. Schäfer 2005). Furthermore, a succession of de-centring approaches including post-structuralist, postmodernist and post-anthropocentric paradigms has suggested the erosion of earlier ‘grand narratives’, the supersession of the ‘enlightenment project’ and even questioned the progressive potential of human labour that explicitly VET theories tend to take for granted. Call for Papers bwp@ Spezial 19 2 Against this background, the bwp@ Special invites contributions that address both VET theory and its application to contemporary issues. The aim is to stimulate a discussion on the continuing significance of VET theory. The aim is to provide space for ideas on how the discipline and its subject could position itself, both nationally and beyond national borders, in its normative-theoretical contours and/or in relation to VET policy and VET practice

The air pressure effect on the homogeneous nucleation of carbon dioxide by molecular simulation

Vapour-liquid equilibria (VLE) and the influence of an inert carrier gas on homogeneous vapour to liquid nucleation are investigated by molecular simulation for quaternary mixtures of carbon dioxide, nitrogen, oxygen, and argon. Canonical ensemble molecular dynamics simulation using the Yasuoka-Matsumoto method is applied to nucleation in supersaturated vapours that contain more carbon dioxide than in the saturated state at the dew line. Established molecular models are employed that are known to accurately reproduce the VLE of the pure fluids as well as their binary and ternary mixtures. On the basis of these models, also the quaternary VLE properties of the bulk fluid are determined with the Grand Equilibrium method. Simulation results for the carrier gas influence on the nucleation rate are compared with the classical nucleation theory (CNT) considering the "pressure effect" [Phys. Rev. Lett. 101: 125703 (2008)]. It is found that the presence of air as a carrier gas decreases the nucleation rate only slightly and, in particular, to a significantly lower extent than predicted by CNT. The nucleation rate of carbon dioxide is generally underestimated by CNT, leading to a deviation between one and two orders of magnitude for pure carbon dioxide in the vicinity of the spinodal line and up to three orders of magnitude in presence of air as a carrier gas. Furthermore, CNT predicts a temperature dependence of the nucleation rate in the spinodal limit, which cannot be confirmed by molecular simulation

Copepod reaction to odor stimuli influenced by cestode infection

The cestode Scktstocephahis solidus uses copepods as first and sticklebacks as second intermediate hosts. For transmission, an infected copepod has to be preyed upon by a stickleback. We used copepods of the species Macrocydops albidus to test whether infected and uninfected copepods differ in their reaction to two kind of simultaneously presented odors: odors of sticklebacks and odors of sticklebacks and conspecifics. By giving this choice, we attempted to force the copepods to make a trade-off between the benefit of risk dilution and possible predator confusion and the costs of food competition and other disadvantages induced by conspecifics. Within 1-8 h after last feeding, uninfected copepods clearly preferred the odors of conspecifics under the chemically simulated threat of predation. This was in contrast to the infected copepods, who tended to avoid the odor of conspecifics. When the time between experiment and last feeding varied, infected copepods showed an increased preference for fish water only (or avoided conspecifics) with increasing hunger level. This suggests that 5. solidus benefits from hunger-induced behavioral changes of its copepod host by influencing its microhabitat selection. The same effect could be found in both sexes; however, it was significantly more pronounced in male than in female copepods. We propose several hypotheses that could explain the difference between the sexes in their infection-dependent microhabitat selection. Key words: cestodes, copepods, Macrocydops albidus, parasite infection, Schistocephalus solidus, sticklebacks. [Bthav Ecol 9:414-418 (1998)] Many helminth parasites use intermediate hosts forgTowth and development. When reaching their infec-tive stage, they depend on their intermediate host bein

Efficient single nucleotide polymorphism discovery in laboratory rat strains using wild rat-derived SNP candidates

BACKGROUND: The laboratory rat (Rattus norvegicus) is an important model for studying many aspects of human health and disease. Detailed knowledge on genetic variation between strains is important from a biomedical, particularly pharmacogenetic point of view and useful for marker selection for genetic cloning and association studies. RESULTS: We show that Single Nucleotide Polymorphisms (SNPs) in commonly used rat strains are surprisingly well represented in wild rat isolates. Shotgun sequencing of 814 Kbp in one wild rat resulted in the identification of 485 SNPs as compared with the Brown Norway genome sequence. Genotyping 36 commonly used inbred rat strains showed that 84% of these alleles are also polymorphic in a representative set of laboratory rat strains. CONCLUSION: We postulate that shotgun sequencing in a wild rat sample and subsequent genotyping in multiple laboratory or domesticated strains rather than direct shotgun sequencing of multiple strains, could be the most efficient SNP discovery approach. For the rat, laboratory strains still harbor a large portion of the haplotypes present in wild isolates, suggesting a relatively recent common origin and supporting the idea that rat inbred strains, in contrast to mouse inbred strains, originate from a single species, R. norvegicus