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

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

What are the evolutionary constraints on larval growth in a trophically transmitted parasite?

For organisms with a complex life cycle, a large larval size is generally beneficial, but it may come at the expense of prolonged development. Individuals that grow fast may avoid this tradeoff and switch habitats at both a larger size and younger age. A fast growth rate itself can be costly, however, as it requires greater resource intake. For parasites, fast larval growth is assumed to increase the likelihood of host death before transmission to the next host occurs. Using the tapeworm Schistocephalus solidus in its copepod first intermediate host, I investigated potential constraints in the parasite’s larval life history. Fast-growing parasites developed infectivity earlier, indicating there is no functional tradeoff between size and developmental time. There was significant growth variation among full-sib worm families, but fast-growing sibships were not characterized by lower host survival or more predation-risky host behavior. Parental investment also had little effect on larval growth rates. The commonly assumed constraints on larval growth and development were not observed in this system, so it remains unclear what prevents worms from exploiting their intermediate hosts more aggressively

Is Mate Choice in Humans MHC-Dependent?

In several species, including rodents and fish, it has been shown that the Major Histocompatibility Complex (MHC) influences mating preferences and, in some cases, that this may be mediated by preferences based on body odour. In humans, the picture has been less clear. Several studies have reported a tendency for humans to prefer MHC-dissimilar mates, a sexual selection that would favour the production of MHC-heterozygous offspring, who would be more resistant to pathogens, but these results are unsupported by other studies. Here, we report analyses of genome-wide genotype data (from the HapMap II dataset) and HLA types in African and European American couples to test whether humans tend to choose MHC-dissimilar mates. In order to distinguish MHC-specific effects from genome-wide effects, the pattern of similarity in the MHC region is compared to the pattern in the rest of the genome. African spouses show no significant pattern of similarity/dissimilarity across the MHC region (relatedness coefficient, R = 0.015, p = 0.23), whereas across the genome, they are more similar than random pairs of individuals (genome-wide R = 0.00185, p<10−3). We discuss several explanations for these observations, including demographic effects. On the other hand, the sampled European American couples are significantly more MHC-dissimilar than random pairs of individuals (R = −0.043, p = 0.015), and this pattern of dissimilarity is extreme when compared to the rest of the genome, both globally (genome-wide R = −0.00016, p = 0.739) and when broken into windows having the same length and recombination rate as the MHC (only nine genomic regions exhibit a higher level of genetic dissimilarity between spouses than does the MHC). This study thus supports the hypothesis that the MHC influences mate choice in some human populations

Physics and Applications of Laser Diode Chaos

An overview of chaos in laser diodes is provided which surveys experimental achievements in the area and explains the theory behind the phenomenon. The fundamental physics underpinning this behaviour and also the opportunities for harnessing laser diode chaos for potential applications are discussed. The availability and ease of operation of laser diodes, in a wide range of configurations, make them a convenient test-bed for exploring basic aspects of nonlinear and chaotic dynamics. It also makes them attractive for practical tasks, such as chaos-based secure communications and random number generation. Avenues for future research and development of chaotic laser diodes are also identified.Comment: Published in Nature Photonic

Genetic variation in the odorant receptors family 13 and the mhc loci influence mate selection in a multiple sclerosis dataset

<p>Abstract</p> <p>Background</p> <p>When selecting mates, many vertebrate species seek partners with major histocompatibility complex (MHC) genes different from their own, presumably in response to selective pressure against inbreeding and towards MHC diversity. Attempts at replication of these genetic results in human studies, however, have reached conflicting conclusions.</p> <p>Results</p> <p>Using a multi-analytical strategy, we report validated genome-wide relationships between genetic identity and human mate choice in 930 couples of European ancestry. We found significant similarity between spouses in the MHC at class I region in chromosome 6p21, and at the odorant receptor family 13 locus in chromosome 9. Conversely, there was significant dissimilarity in the MHC class II region, near the <it>HLA-DQA1 </it>and -<it>DQB1 </it>genes. We also found that genomic regions with significant similarity between spouses show excessive homozygosity in the general population (assessed in the HapMap CEU dataset). Conversely, loci that were significantly dissimilar among spouses were more likely to show excessive heterozygosity in the general population.</p> <p>Conclusions</p> <p>This study highlights complex patterns of genomic identity among partners in unrelated couples, consistent with a multi-faceted role for genetic factors in mate choice behavior in human populations.</p

A Recurrent Stop-Codon Mutation in Succinate Dehydrogenase Subunit B Gene in Normal Peripheral Blood and Childhood T-Cell Acute Leukemia

BACKGROUND: Somatic cytidine mutations in normal mammalian nuclear genes occur during antibody diversification in B lymphocytes and generate an isoform of apolipoprotein B in intestinal cells by RNA editing. Here, I describe that succinate dehydrogenase (SDH; mitochondrial complex II) subunit B gene (SDHB) is somatically mutated at a cytidine residue in normal peripheral blood mononuclear cells (PBMCs) and T-cell acute leukemia. Germ line mutations in the SDHB, SDHC or SDHD genes cause hereditary paraganglioma (PGL) tumors which show constitutive activation of homeostatic mechanisms induced by oxygen deprivation (hypoxia). PRINCIPAL FINDINGS: To determine the prevalence of a mutation identified in the SDHB mRNA, 180 samples are tested. An SDHB stop-codon mutation c.136C>T (R46X) is present in a significant fraction (average = 5.8%, range = less than 1 to 30%, n = 52) of the mRNAs obtained from PBMCs. In contrast, the R46X mutation is present in the genomic DNA of PBMCs at very low levels. Examination of the PBMC cell-type subsets identifies monocytes and natural killer (NK) cells as primary sources of the mutant transcript, although lesser contributions also come from B and T lymphocytes. Transcript sequence analyses in leukemic cell lines derived from monocyte, NK, T and B cells indicate that the mutational mechanism targeting SDHB is operational in T-cell acute leukemia. Accordingly, substantial levels (more than 3%) of the mutant SDHB transcripts are detected in five of 20 primary childhood T-cell acute lymphoblastic leukemia (T-ALL) bone marrow samples, but in none of 20 B-ALL samples. In addition, distinct heterozygous SDHB missense DNA mutations are identified in Jurkat and TALL-104 cell lines which are derived from T-ALLs. CONCLUSIONS: The identification of a recurrent, inactivating stop-codon mutation in the SDHB gene in normal blood cells suggests that SDHB is targeted by a cytidine deaminase enzyme. The SDHB mutations in normal PBMCs and leukemic T cells might play a role in cellular pre-adaptation to hypoxia

Identification of Potential Sites for Tryptophan Oxidation in Recombinant Antibodies Using tert-Butylhydroperoxide and Quantitative LC-MS

Amino acid oxidation is known to affect the structure, activity, and rate of degradation of proteins. Methionine oxidation is one of the several chemical degradation pathways for recombinant antibodies. In this study, we have identified for the first time a solvent accessible tryptophan residue (Trp-32) in the complementary-determining region (CDR) of a recombinant IgG1 antibody susceptible to oxidation under real-time storage and elevated temperature conditions. The degree of light chain Trp-32 oxidation was found to be higher than the oxidation level of the conserved heavy chain Met-429 and the heavy chain Met-107 of the recombinant IgG1 antibody HER2, which have already been identified as being solvent accessible and sensitive to chemical oxidation. In order to reduce the time for simultaneous identification and functional evaluation of potential methionine and tryptophan oxidation sites, a test system employing tert-butylhydroperoxide (TBHP) and quantitative LC-MS was developed. The optimized oxidizing conditions allowed us to specifically oxidize the solvent accessible methionine and tryptophan residues that displayed significant oxidation in the real-time stability and elevated temperature study. The achieved degree of tryptophan oxidation was adequate to identify the functional consequence of the tryptophan oxidation by binding studies. In summary, the here presented approach of employing TBHP as oxidizing reagent combined with quantitative LC-MS and binding studies greatly facilitates the efficient identification and functional evaluation of methionine and tryptophan oxidation sites in the CDR of recombinant antibodies