2,904 research outputs found

    Effects of a large irrigation reservoir on aquatic and riparian plants: a history of survival and loss

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    Dammed rivers have unnatural stream flows, disrupted sediment dynamics, and rearranged geomorphologic settings. Consequently, fluvial biota experiences disturbed functioning in the novel ecosystems. The case study is the large irrigation reservoir Alqueva in Guadiana River, Southern Iberia. The study area was divided into three zones: upstream and downstream of the dam and reservoir. For each zone, species composition and land use and land cover (LULC) were compared before and after the Alqueva Dam implementation. Data consist of aquatic and riparian flora composition obtained from 46 surveys and the area (%) of 12 classes of LULC obtained in 90 riverine sampling units through the analysis of historical and contemporary imagery. There was an overall decrease of several endemic species and on the riparian shrublands and aquatic stands, although di erences in the proportion of functional groups were not significant. Nevertheless, compositional diversity shows a significant decline in the upstream zone while landscape diversity shows an accentuated reduction in the reservoir area and downstream of the dam, which is likely related to the loss of the rocky habitats of the ‘old’ Guadiana River and the homogenization of the riverscape due to the irrigation intensification. The mitigation of these critical changes should be site-specific and should rely on the knowledge of the interactions between surrounding lands, ecological, biogeomorphologic, and hydrological components of the fluvial ecosystemsinfo:eu-repo/semantics/publishedVersio

    Automatic Removal of Flaws in Embedded System Software

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    Tese de mestrado, Segurança Informática, Universidade de Lisboa, Faculdade de Ciências, 2022Currently, embedded systems are present in a myriad of devices, such as Internet of Things, drones, and Cyber-physical Systems. The security of these devices can be critical, depending on the context they are integrated and the role they play (e.g., water plant, car). C is the core language used to develop the software for these devices and is known for missing the bounds of its data types, which leads to vulnerabilities such as buffer overflows. These vulnerabilities, when exploited, cause severe damage and can put human life in danger. Therefore, the software of these devices must be secure. One of the concerns with vulnerable C programs is to correct the code automatically, employing secure code that can remove the existing vulnerabilities and avoid attacks. However, such task faces some challenges after finding the vulnerabilities, namely determining what code is needed to remove them and where to insert that code, maintaining the correct behavior of the application after applying the code correction, and verifying that the generated code correction is secure and effectively removes the vulnerabilities. Another challenge is to accomplish all these elements automatically. This work aims to study diverse types of buffer overflow vulnerabilities in the C programming lan guage, forms to build secure code for invalidating such vulnerabilities, including functions from the C language that can be used to remove flaws. Based on this knowledge, we propose an approach that automatically, after discovering and confirming potential vulnerabilities of an application, applies code correction to fix the vulnerable code of those vulnerabilities verified and validate the new code with fuzzing/attack injection. We implemented our approach and evaluated it with a set of test cases and with real applications. The experimental results showed that the tool detected the intended vulnerabilities and generated corrections capable of removing the vulnerabilities found

    Successful isolation and cultivation of Cylindrospermopsis raciborskii strains isolated from finished drinking water samples

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    This work presents the successful establishment of Cylindrospermosis raciborskii cultures isolated from water samples collected at the exit point of Water Treatment Plant (WTP). An intense bloom dominated by filamentous cyanobacteria (Aphanizomenon spp., Planktothrix spp., Cylindrospermosis raciborskii, Anabaena spp.) occurred in the summer of 2015 in Roxo reservoir (south Portugal). Several cyanotoxins (microcystins, saxitoxins, cylindrospermopsin) were detected in raw and treated water, although at levels below the corresponding regulatory and/or guideline values. Nevertheless, this bloom caused intense unpleasant odour and taste in the water supplied to the populations and cyanobacterial cells (up to 1000 cells.mL-1) were detected in finished water samples collected at the exit point of WTP. Treated water samples collected at the WTP and at the city water deposit were inoculated in Z8 culture medium and cyanobacterial growth was followed by optical microscopy. After 30 days, cyanobacterial growth was observed showing resistance to the treatment processes and maintenance of reprodution capacity. Interestingly, morphometric and molecular analysis revealed the presence of C. raciborskii. Three isolates of this species were obtained and none were cylindrospermopsin- or microcystins-producers, as confirmed by Enzyme Linked Immunosorbent Assays (ELISA) and by amplification of genes (PS, PKS, mcyA-cd, mcyAB, mcyB) involved in those cyanotoxin synthesis. However, the ELISA for saxitoxins was positive for the 3 isolates and confirmation of this toxin production is in progress. To our knowledge, this is the first report on the establishment of successful cultures of C. raciborskii that survived to conventional water treatment processes.N/

    Relatório de estágio em farmácia comunitária

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    Relatório de estágio realizado no âmbito do Mestrado Integrado em Ciências Farmacêuticas, apresentado à Faculdade de Farmácia da Universidade de Coimbr

    Mapping stability : real rational maps of degree zero

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    In memory of our beloved Professor José Rodrigues Santos de Sousa Ramos (1948-2007), who João Cabral, one of the authors of this paper, had the honor of being his student between 2000 and 2006, we wrote this paper following the research by experimentation, using the new technologies to capture a new insight about a problem, as him so much love to do it. His passion was to create new relations between different fields of mathematics. He was a builder of bridges of knowledge, encouraging the birth of new ways to understand this science. One of the areas that Sousa Ramos researched was the iteration of maps and the description of its behavior, using the symbolic dynamics. So, in this issue of this journal, honoring his memory, we use experimental results to find some stable regions of a specific family of real rational maps, the ones that he worked with João Cabral. In this paper we describe a parameter space (a,b) to the real rational maps fa,b(x) = (x2 −a)/(x2 −b), using some tools of dynamical systems, as the study of the critical point orbit and Lyapunov exponents. We give some results regarding the stability of these family of maps when we iterate it, specially the ones connected to the order 3 of iteration. We hope that our results would help to understand better the behavior of these maps, preparing the ground to a more efficient use of the Kneading Theory on these family of maps, using symbolic dynamics

    Academic plagiarism : yielding to temptation

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    Scope: Everybody lies. Plagiarism is pervasive because people are used to lying to succeed. While bringing up someone else’s ideas may be an inadvertent case of cryptomnesia, or unintentional plagiarism, academic plagiarism is hardly ever that case. Building on the existing literature, the aim of this paper is twofold. On the one hand, it contributes to the creation of a new framework for the definition of academic plagiarism within the larger scope of academic dishonesty, or academic misconduct; on the other hand, it identifies forms to recognize and discourage it. Aim: Our aim is to provide the basis for a subsequent empirical study on the phenomenon of plagiarism at LABS-ISCAL hoping to help diminish this practice that is deeply rooted in students in general

    Effectiveness of online corporate collaborative teams

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    With this article we intend to contribute to the understanding of what can make Online Collaborative Teams (OCT) effective. This is done by identifying what can be considered best practices for individual team members, for leaders of OCT, and for the organizations that the teams are a part of. Best practices in these categories were identified from the existing literature related to online teams and collaborative work literature
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