2,172 research outputs found

    Evolutionary biology and genetic techniques for insect control

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    The requirement to develop new techniques for insect control that minimize negative environmental impacts has never been more pressing. Here we discuss population suppression and population replacement technologies. These include sterile insect technique, genetic elimination methods such as the release of insects carrying a dominant lethal (RIDL), and gene driving mechanisms offered by intracellular bacteria and homing endonucleases. We also review the potential of newer or underutilized methods such as reproductive interference, CRISPR technology, RNA interference (RNAi), and genetic underdominance. We focus on understanding principles and potential effectiveness from the perspective of evolutionary biology. This offers useful insights into mechanisms through which potential problems may be minimized, in much the same way that an understanding of how resistance evolves is key to slowing the spread of antibiotic and insecticide resistance. We conclude that there is much to gain from applying principles from the study of resistance in these other scenarios ā€“ specifically, the adoption of combinatorial approaches to minimize the spread of resistance evolution. We conclude by discussing the focused use of GM for insect pest control in the context of modern conservation planning under land-sparing scenarios

    VALUE AND VALUES - WHAT MOTIVATES CORPORATE CITIZENSHIP IN SOUTH AFRICA?

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    The expectation that business has a responsibility to the immediate communities in which they operate and to national development imperatives has become entrenched in society. Globally, businesses have responded by embracing the discourse and practice of corporate social responsibility (CSR), albeit at different levels. Such responses have been shaped by local business cultures and the national economic and political contexts.The discourse on CSR or corporate social investment (CSI) has ascended to global prominence, and there are numerous definitions of what it consists of. However, emerging and common themes point towards legislative compliance, meeting stakeholder expectations and contributing to the upliftment of the broader society while increasing and sustaining business profitability

    On secure network coding with uniform wiretap sets

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    This paper shows determining the secrecy capacity of a unicast network with uniform wiretap sets is at least as difficult as the k-unicast problem. In particular, we show that a general k-unicast problem can be reduced to the problem of finding the secrecy capacity of a corresponding single unicast network with uniform link capacities and one arbitrary wiretap link

    Correction of adversarial errors in networks

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    We design codes to transmit information over a network, some subset of which is controlled by a malicious adversary. The computationally unbounded, hidden adversary knows the message to be transmitted, and can observe and change information over the part of the network he controls. The network nodes do not share resources such as shared randomness or a private key. We first consider a unicast problem in a network with |E| parallel, unit-capacity, directed edges. The rate-region has two parts. If the adversary controls a fraction p < 0.5 of the |E| edges, the maximal throughput equals (1 āˆ’ p)|E|. We describe low-complexity codes that achieve this rate-region. We then extend these results to investigate more general multicast problems in directed, acyclic networks

    Poput traženja duÅ”e u epruveti: banalne zloupotrebe ā€žÄovjeka kojega se mjeriā€ u novoj eri javnog medijskog servisa

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    It has become common place to suggest that the concept and institutions of public service broadcasting (PSB) are being fundamentally challenged by new technologies, new politics and new economics. Out of these challenges, in a kind of noble optimism, has emerged the idea that PSB can be reimagined as public service media, the worth of which can be made measurable and therefore ā€˜accountable.ā€™ This article suggests that not only is this likely misplaced, it also masks the fact that what is actually in play is a historically defined struggle over the values that will constitute modernity.Postalo je gotovo uobičajeno sugerirati kako nove tehnologije, nove politike i nove ekonomije donose mnoge izazove koji ugrožavaju opstojnost koncepta javne radio-televizije (engl. public service broadcasting) i institucija javnih radio-televizija. Iz tih izazova, u duhu plemenitog optimizma, proiziÅ”la je ideja kako javne radio-televizije mogu biti redefinirane u javne medijske servise i kako njihova vrijednost može biti mjerljiva pa samim time i ā€žvjerodostojnaā€. Ovaj pak članak sugerira ne samo da je to vjerojatno pogreÅ”no nego i da je ono Å”to je zapravo na stvari povijesno određena borba oko vrijednosti koje će modernitet prihvatiti

    Poput traženja duÅ”e u epruveti: banalne zloupotrebe ā€žÄovjeka kojega se mjeriā€ u novoj eri javnog medijskog servisa

    Get PDF
    It has become common place to suggest that the concept and institutions of public service broadcasting (PSB) are being fundamentally challenged by new technologies, new politics and new economics. Out of these challenges, in a kind of noble optimism, has emerged the idea that PSB can be reimagined as public service media, the worth of which can be made measurable and therefore ā€˜accountable.ā€™ This article suggests that not only is this likely misplaced, it also masks the fact that what is actually in play is a historically defined struggle over the values that will constitute modernity.Postalo je gotovo uobičajeno sugerirati kako nove tehnologije, nove politike i nove ekonomije donose mnoge izazove koji ugrožavaju opstojnost koncepta javne radio-televizije (engl. public service broadcasting) i institucija javnih radio-televizija. Iz tih izazova, u duhu plemenitog optimizma, proiziÅ”la je ideja kako javne radio-televizije mogu biti redefinirane u javne medijske servise i kako njihova vrijednost može biti mjerljiva pa samim time i ā€žvjerodostojnaā€. Ovaj pak članak sugerira ne samo da je to vjerojatno pogreÅ”no nego i da je ono Å”to je zapravo na stvari povijesno određena borba oko vrijednosti koje će modernitet prihvatiti

    Habitat Management to Reduce Human Exposure to Trypanosoma cruzi and Western Conenose Bugs (Triatoma protracta).

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    Chagas disease, which manifests as cardiomyopathy and severe gastrointestinal dysfunction, is caused by Trypanosoma cruzi, a vector-borne parasite. In California, the vector Triatoma protracta frequently colonizes woodrat (Neotoma spp.) lodges, but may also invade nearby residences, feeding upon humans and creating the dual risk of bite-induced anaphylaxis and T. cruzi transmission. Our research aimed to assess T. cruzi presence in woodrats in a previously unstudied northern California area, statistically evaluate woodrat microhabitat use with respect to vegetation parameters, and provide guidance for habitat modifications to mitigate public health risks associated with Tr. protracta exposure. Blood samples from big-eared woodrats (N. macrotis) trapped on rural private properties yielded a T. cruzi prevalence of 14.3%. Microhabitat analyses suggest that modifying vegetation to reduce understory density within a 40Ā meter radius of human residences might minimize woodrat lodge construction within this buffer area, potentially decreasing human exposure to Tr. protracta

    Routing for Security in Networks with Adversarial Nodes

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    We consider the problem of secure unicast transmission between two nodes in a directed graph, where an adversary eavesdrops/jams a subset of nodes. This adversarial setting is in contrast to traditional ones where the adversary controls a subset of links. In particular, we study, in the main, the class of routing-only schemes (as opposed to those allowing coding inside the network). Routing-only schemes usually have low implementation complexity, yet a characterization of the rates achievable by such schemes was open prior to this work. We first propose an LP based solution for secure communication against eavesdropping, and show that it is information-theoretically rate-optimal among all routing-only schemes. The idea behind our design is to balance information flow in the network so that no subset of nodes observe "too much" information. Interestingly, we show that the rates achieved by our routing-only scheme are always at least as good as, and sometimes better, than those achieved by "na\"ive" network coding schemes (i.e. the rate-optimal scheme designed for the traditional scenario where the adversary controls links in a network rather than nodes.) We also demonstrate non-trivial network coding schemes that achieve rates at least as high as (and again sometimes better than) those achieved by our routing schemes, but leave open the question of characterizing the optimal rate-region of the problem under all possible coding schemes. We then extend these routing-only schemes to the adversarial node-jamming scenarios and show similar results. During the journey of our investigation, we also develop a new technique that has the potential to derive non-trivial bounds for general secure-communication schemes

    Evaluating local implementation: An evidence-based approach

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    This article, based on data collected from a year-long study, investigates the evaluation of a UK local government policy implementation and the use of evaluation data as an evidence-base for public policy (Bovaird & Loeffler, 2007; McCoy & Hargie, 2001; Schofield, 2004; Stern, 2008). Our case study highlights a number of issues. First, uncertainty and ambiguity of policy direction inhibiting the establishment of clear evaluation goals, which, second, results in frustration among stakeholders at a perceived disparity between what we term problem-inspired policy and problem-solving policy. Finally, this perception can be compounded by a lack of consideration for local variations of, for example, specific cultures, geographies or historical contexts. In responding to these problems our article argues that regardless of where policy control and decision-making occurs, the importance of the experiences of policy-implementers at a local level (where subject/geographical/cultural specialism and familiarisation exists) is crucial.N/
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