11 research outputs found

    An IND-CCA Rank Metric Encryption Scheme Implementation

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    TCC(graduação) - Universidade Federal de Santa Catarina. Centro Tecnológico. Ciências da Computação.The advances in the field of quantum computation impose a severe threat to the cryptographic primitives used nowadays. In particular, the community predicts public-key cryptography will be turned completely obsolete if these computers are ever produced. In the light of these facts, researchers are contributing in a great effort to preserve current information systems against quantum attacks. Post-quantum cryptography is the area of research that aims to develop cryptographic systems to resist against both quantum and classical computers while assuring interoperability with existing networks and protocols. This work considers the use of Gabidulin codes—a class of error-correcting codes using rank metric—in the construction of encryption schemes. We first introduce error-correcting codes in general and Gabidulin codes in particular. Then, we present the use of these codes in the context of public-key encryption schemes and show that, while providing the possibility of smaller key sizes, they are especially challenging in terms of security. We present the scheme proposed in Loidreau in 2017, showing that although correcting the main weakness in previous propositions, it is still insecure related to chosen-ciphertext attacks. Then, we present a modification to the scheme, proposed by Shehhi et al. to achieve CCA security, and provide an implementation. We also analyze the theoretical complexity of recent attacks to rank-based cryptography and propose a set of parameters for the scheme

    Are Strength Indicators and Skin Temperature Affected by the Type of Warm-Up in Paralympic Powerlifting Athletes?

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    (1) Background: the present study aimed to evaluate the effect of different types of warm-ups on the strength and skin temperature of Paralympic powerlifting athletes. (2) Methods: the participants were 15 male Paralympic powerlifting athletes. The effects of three different types of warm-up (without warm-up (WW), traditional warm-up (TW), or stretching warm-up (SW)) were analyzed on static and dynamic strength tests as well as in the skin temperature, which was monitored by thermal imaging. (3) Results: no differences in the dynamic and static indicators of the force were shown in relation to the different types of warm-ups. No significant differences were found in relation to peak torque (p = 0.055, F = 4.560, η2p = 0.246 medium effect), and one-repetition maximum (p = 0.139, F = 3.191, η2p = 0.186, medium effect) between the different types of warm-ups. In the thermographic analysis, there was a significant difference only in the pectoral muscle clavicular portion between the TW (33.04 ± 0.71 °C) and the WW (32.51 ± 0.74 °C) (p = 0.038). The TW method also presented slightly higher values than the SW and WW in the pectoral muscles sternal portion and the deltoid anterior portion, but with p-value > 0.05. (4) Conclusions: the types of warm-ups studied do not seem to interfere with the performance of Paralympic Powerlifting athletes. However, the thermal images showed that traditional warm-up best meets the objectives expected for this preparation phase.post-print1305 K

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Pervasive gaps in Amazonian ecological research

    Get PDF

    Pervasive gaps in Amazonian ecological research

    Get PDF
    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

    Analysis of Waste Biogas (Landfills) applied to Power Generation

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    En Brasil, a pesar del alto porcentaje de las energías renovables en el mix energético en comparación con el promedio mundial, el uso de gas generado por los vertederos para la generación de energía es aún incipiente. Hay vertederos desplegadas recientemente con el objetivo de producir electricidad a partir de biogás, pero las plantas más viejas, no tienen esta estructura. Dado que la industria petrolera es de alto consumo energético, este artículo propone la evaluación de la utilización de los gases residuales en el sistema de generación de vapor de una refinería típica en Brasil para generar electricidad y alimentar las unidades de proceso de la refinería. En este sentido, se presenta un análisis basado en datos reales para contextualizar y cuantificar el potencial de biogás de residuos en Brasil. Este estudio considera un relleno al final de la vida (17 años), y la reutilización del gas residual generado hasta el agotamiento completo de gases, teniendo en cuenta un estudio de casos con datos reales de un vertedero existenteIn Brazil, despite the high share of renewable energy sources in the energy mix compared to the world average, the use of gas generated by landfills for power generation is still incipient. There are landfills recently implanted with the purpose to produce electricity from biogas, but the oldest installations do not have this structure. Since the oil industry is energy intensive, the article proposes the evaluation of waste gas use in the steam generation system of a typical refinery in Brazil to generate electricity and feed the refinery process units and considering the economic impact. In this sense, it presents an analysis based on real data to contextualize and quantify the waste biogas potential in a specific landfill in Brazil. The study considers a landfill at the end of life (17 years), and the reuse of the residual gas generated until the full depletion of gases considering a case study with real data obtained from an existing landfil

    Post-acute COVID-19 in three doses vaccinated autoimmune rheumatic diseases patients: frequency and pattern of this condition

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    Abstract Background Data on post-acute COVID-19 in autoimmune rheumatic diseases (ARD) are scarce, focusing on a single disease, with variable definitions of this condition and time of vaccination. The aim of this study was to evaluate the frequency and pattern of post-acute COVID-19 in vaccinated patients with ARD using established diagnosis criteria. Methods Retrospective evaluation of a prospective cohort of 108 ARD patients and 32 non-ARD controls, diagnosed with SARS-CoV-2 infection (RT-PCR/antigen test) after the third dose of the CoronaVac vaccine. Post-acute COVID-19 (≥ 4 weeks and > 12 weeks of SARS-CoV-2 symptoms) were registered according to the established international criteria. Results ARD patients and non-ARD controls, balanced for age and sex, had high and comparable frequencies of ≥ 4 weeks post-acute COVID-19 (58.3% vs. 53.1%, p = 0.6854) and > 12 weeks post-acute COVID-19 (39.8% vs. 46.9%, p = 0.5419). Regarding ≥ 4 weeks post-acute COVID-19, frequencies of ≥ 3 symptoms were similar in ARD and non-ARD controls (54% vs. 41.2%, p = 0.7886), and this was also similar in > 12 weeks post-acute COVID-19 (68.3% vs. 88.2%, p = 0.1322). Further analysis of the risk factors for ≥ 4 weeks post-acute COVID-19 in ARD patients revealed that age, sex, clinical severity of COVID-19, reinfection, and autoimmune diseases were not associated with this condition (p > 0.05). The clinical manifestations of post-acute COVID-19 were similar in both groups (p > 0.05), with fatigue and memory loss being the most frequent manifestations. Conclusion We provide novel data demonstrating that immune/inflammatory ARD disturbances after third dose vaccination do not seem to be a major determinant of post-acute COVID-19 since its pattern is very similar to that of the general population. Clinical Trials platform (NCT04754698)
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