293 research outputs found

    Measuring Information Leakage in Website Fingerprinting Attacks and Defenses

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    Tor provides low-latency anonymous and uncensored network access against a local or network adversary. Due to the design choice to minimize traffic overhead (and increase the pool of potential users) Tor allows some information about the client's connections to leak. Attacks using (features extracted from) this information to infer the website a user visits are called Website Fingerprinting (WF) attacks. We develop a methodology and tools to measure the amount of leaked information about a website. We apply this tool to a comprehensive set of features extracted from a large set of websites and WF defense mechanisms, allowing us to make more fine-grained observations about WF attacks and defenses.Comment: In Proceedings of the 2018 ACM SIGSAC Conference on Computer and Communications Security (CCS '18

    A Soil Management Assessment Framework (SMAF) Evaluation of Brazilian Sugarcane Expansion on Soil Quality

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    The Soil Management Assessment Framework (SMAF) was developed to evaluate impacts of land use and management practices on soil quality (SQ), but its suitability for Brazilian tropical soils was unknown. We hypothesized that SMAF would be sensitive enough to detect SQ changes associated with sugarcane (Saccharum officinarum L.) expansion for ethanol production. Field studies were performed at three sites across the south-central region of Brazil, aiming to quantify the impacts of a land use change sequence (i.e., native vegetation–pasture–sugarcane) on SQ. Eight soil indicators were individually scored using SMAF curves developed primarily for North American soils and integrated into an overall Soil Quality Index (SQI) and its chemical, physical, and biological sectors. The SMAF scores were correlated with two other approaches used to assess SQ changes, soil organic C (SOC) stocks and Visual Evaluation of Soil Structure (VESS) scores. Our findings showed that the SMAF was an efficient tool for assessing land use change effects on the SQ of Brazilian tropical soils. The SMAF scoring curves developed using robust algorithms allowed proper assignment of scores for the soil chemical, physical, and biological indicators assessed. The SQI scores were significantly correlated with SOC stocks and VESS scores. Long-term transition from native vegetation to extensive pasture promoted significant decreases in soil chemical, physical, and biological indicators. Overall SQI suggested that soils under native vegetation were functioning at 87% of their potential capacity, while pasture soils were functioning at 70%. Conversions of pasture to sugarcane induced slight improvements in SQ, primarily because of improved soil fertility. Sugarcane soils are functioning at 74% of their potential capacity. Based on this study, management strategies were developed to improve SQ and the sustainability of sugarcane production in Brazil

    Análise de componentes principais de atributos químicos e físicos do solo limitantes à produtividade de grãos.

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    O objetivo deste trabalho foi avaliar, por meio da análise dos componentes principais, a redução na dimensionalidade de atributos químicos e físicos do solo para a compreensão da variabilidade espacial e temporal da produtividade de culturas de grãos. A área experimental, de 54 ha, é manejada em agricultura de precisão há oito anos. Com base em seis mapas de colheita (soja - safra 2000/2001; milho - 2001/2002; soja - 2002/2003; trigo - 2003; soja - 2003/2004; e milho - 2004/2005), a área foi dividida em três zonas de produtividade de grãos (alta, média e baixa). Foram definidos 15 pontos georreferenciados representativos, para determinação de atributos químicos e físicos do solo, o que totalizou 63 variáveis analisadas. Entre os atributos químicos, o elevado teor de K no solo é o que melhor explica a variabilidade espacial da produtividade das culturas de grãos, provavelmente em razão do desbalanço das relações Ca:K e Mg:K. A zona de baixa produtividade apresentou baixa qualidade física do solo. Neste caso, a infiltração de água no solo, isoladamente, é a variável que melhor explica o desempenho das culturas de grãos. A análise dos componentes principais dos atributos químicos e físicos do solo é estratégia eficiente para explicar a variabilidade espacial e temporal da produtividade de culturas de grãos

    Once-monthly paliperidone palmitate in recently diagnosed and chronic non-acute patients with schizophrenia

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    OBJECTIVE: To explore the treatment response, tolerability and safety of once-monthly paliperidone palmitate (PP1M) in non-acute patients switched to oral antipsychotics stratified by time since diagnosis as recently diagnosed (3 years). RESEARCH DESIGN AND METHODS: Post-hoc analysis of a prospective, interventional, single-arm, multicentre, open-label, 6-month study performed in 233 recently diagnosed and 360 chronic patients. MAIN OUTCOME MEASURES: The proportion achieving treatment response (defined as >/=20% improvement in Positive and Negative Syndrome Scale [PANSS] total score from baseline to endpoint) and maintained efficacy (defined as non-inferiority in the change in PANSS total score at endpoint [Schuirmann's test]). RESULTS: 71.4% of recently diagnosed and 59.2% of chronic patients showed a >/=20% decrease in PANSS total score (p=0.0028 between groups). Changes in PANSS Marder factors, PANSS subscales, and the proportion of patients with a Personal and Social Performance scale (PSP) total score of 71-100 were significantly greater in recently diagnosed compared with chronic patients. PP1M was well tolerated, presenting no new safety signals. CONCLUSION: These data show that recently diagnosed patients treated with PP1M had a significantly higher treatment response and improved functioning, as assessed by the PSP total score, than chronic patients

    Light dependent redox catalysis by Photosystem I complexes encapsulated in organic nanoparticles

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    Photosystem I (PSI) is a pigment binding multi-subunit protein complexes involved in photosynthesis. PSI is localized in the thylakoid membranes and catalyze the electron transfer reaction from plastocyanin to ferredoxin, as one of the main steps involved in conversion of light energy into chemical energy. PSI is highly efficiency with a photochemical efficiency close to one. Several attempts have doing in the past in order to exploit the high efficiency and high stability of PSI in an extra-cellular context in order to catalyze electron transfer reactions: in this work we present an innovative solution for exploiting the photochemical properties of PSI, by encapsulation of PSI complexes in organic nanoparticles. Nanoparticles offer a protected environment to the encapsulated molecule, giving it the possibility of preserving its functional properties and studying how they change over time. In this work the complete characterization, both morphological and functional, of nanostructures obtained by encapsulation of PSI complexes purified from higher plants with PLGA (poly lactic-co-glycolic acid) polymer is presented. The results obtained by transient absorption and time-resolved fluorescence demonstrate that encapsulated PSI were characterized by an higher photochemcial activity compared to PSI complexes in detergent solution. Moreover, encapsulated PSI maintained the high efficiency observed for several weeks even if exposed to very strong light, being more stable compared to PSI in detergent solution. Finally, the nanostructures obtained by encapsulated PSI were able to catalyze light dependent redox reactions with electron acceptors and donors outside the nanostructures Potential application of these PLGA encapsulated PSI in different fields are thus presented and discussed

    A Soil Management Assessment Framework (SMAF) Evaluation of Brazilian Sugarcane Expansion on Soil Quality

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    The Soil Management Assessment Framework (SMAF) was developed to evaluate impacts of land use and management practices on soil quality (SQ), but its suitability for Brazilian tropical soils was unknown. We hypothesized that SMAF would be sensitive enough to detect SQ changes associated with sugarcane (Saccharum officinarum L.) expansion for ethanol production. Field studies were performed at three sites across the south-central region of Brazil, aiming to quantify the impacts of a land use change sequence (i.e., native vegetation–pasture–sugarcane) on SQ. Eight soil indicators were individually scored using SMAF curves developed primarily for North American soils and integrated into an overall Soil Quality Index (SQI) and its chemical, physical, and biological sectors. The SMAF scores were correlated with two other approaches used to assess SQ changes, soil organic C (SOC) stocks and Visual Evaluation of Soil Structure (VESS) scores. Our findings showed that the SMAF was an efficient tool for assessing land use change effects on the SQ of Brazilian tropical soils. The SMAF scoring curves developed using robust algorithms allowed proper assignment of scores for the soil chemical, physical, and biological indicators assessed. The SQI scores were significantly correlated with SOC stocks and VESS scores. Long-term transition from native vegetation to extensive pasture promoted significant decreases in soil chemical, physical, and biological indicators. Overall SQI suggested that soils under native vegetation were functioning at 87% of their potential capacity, while pasture soils were functioning at 70%. Conversions of pasture to sugarcane induced slight improvements in SQ, primarily because of improved soil fertility. Sugarcane soils are functioning at 74% of their potential capacity. Based on this study, management strategies were developed to improve SQ and the sustainability of sugarcane production in Brazil

    Straw removal effects on sugarcane root system and stalk yield.

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    The sugarcane (Saccharum spp. L.) mechanical harvesting system leaves a large amount of straw mulch on the soil surface. The straw mulch may affect soil conditions, root regrowth, and sugarcane yield. Thus, this study assessed the response of sugarcane root system growth and stalk yield to different rates of straw removal. An experiment was conducted in a Rhodic Kandiudox with sand clay loam texture to test the impact of four rates of straw removal: no removal (18.9 Mg ha−1 of dry mass); moderate removal (8.7 Mg ha−1); high removal (4.2 Mg ha−1) and total removal on sugarcane root system and stalk yield. Higher concentrations of roots (60%) were found in the first 40 cm of soil. Moderate straw removal resulted in higher root mass (3.6 Mg ha−1 ) and stalk production (23 Mg ha−1 of dry mass). However, no straw removal reduced root mass by 20% (105 Mg ha−1). Through regression analysis, it was estimated that retaining between 8.5 and 13 Mg ha−1 of straw resulted in the highest root mass and stalk yield. Managing straw removal to retain a moderate amount enables producers to sustain suitable soil conditions for sugarcane root growth and stalk production while providing straw for industrial use

    Is the expansion of sugarcane over pasturelands a sustainable strategy for Brazil's bioenergy industry?

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    The authors gratefully thank the São Paulo Research Foundation (FAPESP) (grants # 2014/08632-9 # 2015/14122-6, # 2013/17581-6, # 2014/16612-8 and 2018/09845-7) for the scholarship granted while this research was carried out, and CNPq (grants # 402992/2013-0 and # 311661/2014-9) for the financial support of the present research. Anonymous reviewers are also thanked for their valuable criticisms and comments, which led to substantial improvements of this manuscript.Peer reviewedPostprintPostprin
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