226 research outputs found

    Characterisation of small ruminant production in Crete

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    Subproject 2 of the LowInputBreeds project aims to improve performance, animal health & welfare, and product quality in organic and low input breed sheep production systems. One focus is breeding under Mediterranean condition

    Subproject 2: Sheep: Ethical Problems and Breeding Goals

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    - Lately production of various sheep and goat products has been raised especially in Mediterranean countries which have a long tradition in breeding such animals - Sheep and goat breeding in those countries in fact in the best choice in order to exploit the specific area and climate condition

    PPP-Completeness with Connections to Cryptography

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    Polynomial Pigeonhole Principle (PPP) is an important subclass of TFNP with profound connections to the complexity of the fundamental cryptographic primitives: collision-resistant hash functions and one-way permutations. In contrast to most of the other subclasses of TFNP, no complete problem is known for PPP. Our work identifies the first PPP-complete problem without any circuit or Turing Machine given explicitly in the input, and thus we answer a longstanding open question from [Papadimitriou1994]. Specifically, we show that constrained-SIS (cSIS), a generalized version of the well-known Short Integer Solution problem (SIS) from lattice-based cryptography, is PPP-complete. In order to give intuition behind our reduction for constrained-SIS, we identify another PPP-complete problem with a circuit in the input but closely related to lattice problems. We call this problem BLICHFELDT and it is the computational problem associated with Blichfeldt's fundamental theorem in the theory of lattices. Building on the inherent connection of PPP with collision-resistant hash functions, we use our completeness result to construct the first natural hash function family that captures the hardness of all collision-resistant hash functions in a worst-case sense, i.e. it is natural and universal in the worst-case. The close resemblance of our hash function family with SIS, leads us to the first candidate collision-resistant hash function that is both natural and universal in an average-case sense. Finally, our results enrich our understanding of the connections between PPP, lattice problems and other concrete cryptographic assumptions, such as the discrete logarithm problem over general groups

    Glitch Art Narratives: An investigation of the relation between noise and meaning

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    This thesis investigates the ontological meta-narratives of glitch art and focuses on it as the transition from images with noise, into a site of meaning. In the first chapter I will discuss glitch art as a failure in communication that stimulates our perception. By relating glitch art to noise art, I will describe the prevalence of a common artistic approach towards errors, while through Fiske’s notion of ‘entropy’ I will examine how unconventional information affects us. These findings, combined with the analysis of distinct glitch art typologies in the second chapter, will highlight the instrumentalization of accidents as a method for processing reality. This method will be investigated through a content analysis of a digital glitch-art work that will be bound with Lyotard’s notion of the ‘aesthetics of post-modernity’ and Virilio’s concept of a ‘vision machine’. This contextualization will introduce glitch art as a metonym for reality and as a mechanism that revolutionizes our perception and reinforces our tolerance against the stress that Virilio ascribes to the unknown source of the Original Accident. The third chapter is investigating hybrid glitch art forms as the result of this meaning making process. Through the examination of an oil painting that imitates the visual manifestation of digital errors, I will demonstrate that there is a semiotic interrelation between glitch art and the Accident, which simultaneously redefines the ontology of the former, as glitch art is becoming the Myth of the Accident. As a result, this thesis will investigate the connections of ontological meta-narratives in contemporary art to mechanisms for acquiring knowledge and processing reality, in an example of the current phenomenon of glitch art

    Occupational Fraud Detection Through Visualization

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    Occupational fraud affects many companies worldwide causing them economic loss and liability issues towards their customers and other involved entities. Detecting internal fraud in a company requires significant effort and, unfortunately cannot be entirely prevented. The internal auditors have to process a huge amount of data produced by diverse systems, which are in most cases in textual form, with little automated support. In this paper, we exploit the advantages of information visualization and present a system that aims to detect occupational fraud in systems which involve a pair of entities (e.g., an employee and a client) and periodic activity. The main visualization is based on a spiral system on which the events are drawn appropriately according to their time-stamp. Suspicious events are considered those which appear along the same radius or on close radii of the spiral. Before producing the visualization, the system ranks both involved entities according to the specifications of the internal auditor and generates a video file of the activity such that events with strong evidence of fraud appear first in the video. The system is also equipped with several different visualizations and mechanisms in order to meet the requirements of an internal fraud detection system

    On the Complexity of Modulo-q Arguments and the Chevalley - Warning Theorem

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    We study the search problem class PPA_q defined as a modulo-q analog of the well-known polynomial parity argument class PPA introduced by Papadimitriou (JCSS 1994). Our first result shows that this class can be characterized in terms of PPA_p for prime p. Our main result is to establish that an explicit version of a search problem associated to the Chevalley - Warning theorem is complete for PPA_p for prime p. This problem is natural in that it does not explicitly involve circuits as part of the input. It is the first such complete problem for PPA_p when p ? 3. Finally we discuss connections between Chevalley-Warning theorem and the well-studied short integer solution problem and survey the structural properties of PPA_q

    Sustainable intensification? Increased production diminishes omega-3 content of sheep milk

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    Intensifying agricultural production alters food composition, but this is often ignored when assessing system sustainability, yet it could compromise consumers’ health and the concept of ‘sustainable diets’. Here we consider milk composition from Mediterranean dairy sheep, finding inferior fatty acid (FA) profiles with respect to consumer health as a result of a more intensive system of production. Semi-intensive management did produce 57% more milk per ewe with 20% lower fat content, but inferior fat composition. Milk had a nutritionally poorer fatty acid (FA) profile, with 18% less omega-3 FA (n-3) (19% less long-chain n-3) and 7% less monounsaturated FA but 3% more saturated FA (9% higher in C14:0) concentrations compared with ewes under traditional, extensive management. Redundancy analysis identified close associations between fat composition and animal diets, particularly concentrate supplementation and grazing cultivated pasture - n-3 was associated with grazing diverse, native mountain pastures. The paper questions if identifying such key elements in traditional systems could be deployed for ‘sustainable intensification’ to maintain food quality whilst increasing output

    Abundance, zoonotic potential and risk factors of intestinal parasitism amongst dog and cat populations: The scenario of Crete, Greece

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    Background: The objectives of this study were to evaluate the prevalence and infection intensity of intestinal parasites in different dog and cat populations in Crete, Greece, estimate the zoonotic risk and identify risk factors. Methods: Faecal samples from shelter, household and shepherd dogs and shelter and household cats were analyzed using sedimentation/flotation techniques. Giardia and Cryptosporidium were detected by a quantitative direct immunofluorescence assay (IFA). PCR and sequencing was performed to evaluate the zoonotic potential of Giardia and Cryptosporidium positive samples. Results: Totals of 879 dog and 264 cat faecal samples were examined. In dogs, the overall prevalence was 25.2% (CI: 22.4-28.1) for Giardia spp.; 9.2% (CI: 7.3-11.1) for Ancylostoma/Uncinaria spp.; 7.6% (CI: 5.9-9.4) for Toxocara spp.; 5.9% (CI: 4.4-7.5) for Cryptosporidium spp.; 4.6% (CI: 3.2-5.9) for Cystoisospora spp.; 2.7% (CI: 1.7-3.8) for Toxascaris leonina; 1.7% (CI: 0.9-2.6) for Capillaria spp.; 0.8% (CI: 0.2-1.4) for taeniid eggs; 0.2% (CI: 0-0.5) for Dipylidium caninum; and 0.1% (CI: 0-0.3) for Strongyloides stercoralis. In cats, the prevalence was 20.5% (CI: 15.6-25.3) for Giardia spp.; 9.5% (CI: 5.9-13.0) for Cystoisospora spp.; 8.3% (CI: 5.0-11.7) for Toxocara spp.; 7.6% (CI: 4.4-10.8) for Ancylostoma/Uncinaria spp.; 6.8% (CI: 3.8-9.9) for Cryptosporidium spp.; 4.2% (CI: 1.8-6.6) for Capillaria spp.; 0.8% (CI: 0-1.8) for taeniid eggs; and 0.4% (CI: 0-1.1) for Hammondia/Toxoplasma. Concerning the risk factors evaluated, there was a negative association between age and Giardia infection and between age and T. leonina infection intensity for dogs. Sequencing results revealed the presence of mainly animal-specific G. duodenalis assemblages C and D in dogs and assemblages F, C and BIV-like in cats, with only a limited number of (co-) infections with assemblage A. As for Cryptosporidium, the dog-specific C. canis and the pig-specific C. scrofarum were detected in dogs and the cat-specific C. felis was detected in cats. Conclusions: High levels of parasitism in both dogs and cats were recorded. Giardia was the most prevalent parasite in all dog and cat populations except for shepherd dogs. Genotyping results suggest a limited zoonotic risk of Giardia and Cryptosporidium infections from dogs and cats in Crete. Taeniid eggs were more prevalent in shepherd dogs suggesting access to carcasses and posing a threat for cystic echinococcosis transmission. Infection rates of Toxocara spp. in both dogs and cats show that companion animals could be a significant source of infection to humans
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