Static noise margin analysis for CMOS logic cells in near-threshold

The advancement of semiconductor technology enabled the fabrication of devices with faster switching activity and chips with higher integration density. However, these advances are facing new impediments related to energy and power dissipation. Besides, the increasing demand for portable devices leads the circuit design paradigm to prioritize energy efficiency instead of performance. Altogether, this scenario motivates engineers towards reducing the supply voltage to the near and subthreshold regime to increase the lifespan of battery-powered devices. Even though operating in these regime offer interesting energy-frequency trade-offs, it brings challenges concerning noise tolerance. As the supply voltage reduces, the available noise margins decrease, and circuits become more prone to functional failures. In addition, near and subthreshold circuits are more susceptible to manufacturing variability, hence further aggravating noise issues. Other issues, such as wire minimization and gate fan-out, also contribute to the relevance of evaluating the noise margin of circuits early in the design Accordingly, this work investigates how to improve the static noise margin of digital synchronous circuits that will operate at the near/subthreshold regime. This investigation produces a set of three original contributions. The first is an automated tool to estimate the static noise margin of CMOS combinational cells. The second contribution is a realistic static noise margin estimation methodology that considers process-voltage-temperature variations. Results show that the proposed methodology allows to reduce up to 70% of the static noise margin pessimism. Finally, the third contribution is the noise-aware cell design methodology and the inclusion of a noise evaluation of complex circuits during the logic synthesis. The resulting library achieved higher static noise margin (up to 24%) and less spread among different cells (up to 62%).Os avanços na tecnologia de semicondutores possibilitou que se fabricasse dispositivos com atividade de chaveamento mais rápida e com maior capacidade de integração de transistores. Estes avanços, todavia, impuseram novos empecilhos relacionados com a dissipação de potência e energia. Além disso, a crescente demanda por dispositivos portáteis levaram à uma mudança no paradigma de projeto de circuitos para que se priorize energia ao invés de desempenho. Este cenário motivou à reduzir a tensão de alimentação com qual os dispositivos operam para um regime próximo ou abaixo da tensão de limiar, com o objetivo de aumentar sua duração de bateria. Apesar desta abordagem balancear características de performance e energia, ela traz novos desafios com relação a tolerância à ruído. Ao reduzirmos a tensão de alimentação, também reduz-se a margem de ruído disponível e, assim, os circuitos tornam-se mais suscetíveis à falhas funcionais. Somado à este efeito, circuitos com tensões de alimentação nestes regimes são mais sensíveis à variações do processo de fabricação, logo agravando problemas com ruído. Existem também outros aspectos, tais como a miniaturização das interconexões e a relação de fan-out de uma célula digital, que incentivam a avaliação de ruído nas fases iniciais do projeto de circuitos integrados Por estes motivos, este trabalho investiga como aprimorar a margem de ruído estática de circuitos síncronos digitais que irão operar em tensões no regime de tensão próximo ou abaixo do limiar. Esta investigação produz um conjunto de três contribuições originais. A primeira é uma ferramenta capaz de avaliar automaticamente a margem de ruído estática de células CMOS combinacionais. A segunda contribuição é uma metodologia realista para estimar a margem de ruído estática considerando variações de processo, tensão e temperatura. Os resultados obtidos mostram que a metodologia proposta permitiu reduzir até 70% do pessimismo das margens de ruído estática, Por último, a terceira contribuição é um fluxo de projeto de células combinacionais digitais considerando ruído, e uma abordagem para avaliar a margem de ruído estática de circuitos complexos durante a etapa de síntese lógica. A biblioteca de células resultante deste fluxo obteve maior margem de ruído (até 24%) e menor variação entre diferentes células (até 62%)

Niche differentiation mechanisms among canopy frugivores and zoochoric trees in the northeastern extreme of the Amazon

Frugivores and zoocoric trees represent an important proportion of tropical rainforest biodiversity. As niche differences favor species coexistence, we aimed to evaluate morphological and temporal niche segregation mechanisms among zoochoric trees and canopy frugivores in a tropical rainforest in the northeastern extreme of the Brazilian Amazon. We tested the effects of fruit morphology, tree size, frugivore body size and time of day on fruit consumption. We recorded the frugivore species that fed on 72 trees (44 species, 22 genera) and whether these frugivores swallowed the seeds. We monitored trees only once from 07:00 to 17:00 h between January and September 2017. We observed fruit consumption in 20 of the 72 trees. Seventy-three frugivore individuals from 22 species visited the trees. Heavier fruits were consumed by larger frugivores, while seed size was inversely correlated with frugivore size. Narrower fruits and fruits with smaller seeds had greater probability of having their seeds ingested, and larger frugivores were more prone to ingest seeds. Trees bearing fruits with smaller seeds were visited by a greater number of frugivores. Taxonomic groups differed in the time of arrival at fruiting trees. None of the evaluated variables (fruit weight and size, and seed size) affected the richness of frugivores that visited the trees. We concluded that, in the studied forest, fruit morphology (weight, size and seed size) is a niche segregation mechanism among zoochoric trees, while body size and time of day are niche segregation mechanisms among frugivores.info:eu-repo/semantics/publishedVersio

Avaliação Ambiental do Parque Urbano Chico Mendes, Porto Alegre- RS, Brasil

http://dx.doi.org/10.5902/2179460X14419The environmental impacts in this XXI century increased dangerously and, thus, was reinforced the paradigm of maintaining the environment. In the context of an urban forest, was recommended the increase of green areas and the connectivity between them, as well as encourage greater use of native essences, even as an expansion in the diversity of species. The aim of this study was to diagnose the environmental conditions of Chico Mendes Municipal Park. The qualitative analysis of avifauna and plant was based on the presence and absence compared to other studies. The Sørensen index was estimated for flora and avifauna, and a review of the phytosanitary conditions of tree specimens. Thus, in the present study were cataloged 51 species of birds in the Chico Mendes Park, being 23 considered migratory and 28 as residents, 2 species of amphibians, reptiles 10, 9 mammals and 55 plants. The Sørensen index for avifauna expressed a similarity value of 0.65420 when compared to other studies; while the same index for tree flora was in order of 0.37500. It is necessary the development of awareness and transformation tools that promote behavioral change in the surrounding community.O objetivo do presente estudo foi diagnosticar as condições ambientais do Parque Municipal Chico Mendes. A análise qualitativa da avifauna e da flora baseou-se na presença e ausência comparativamente a outros estudos; sendo estimado Índice de Sørensen para flora e para avifauna, e uma avaliação das condições fitossanitárias dos espécimes arbóreos. Assim, no presente estudo, foram catalogadas cinqüenta e uma espécies de aves no Parque Chico Mendes, sendo vinte e três consideradas como migratórias e vinte e oito como residentes, duas espécies de anfíbios, dez de répteis, nove de mamíferos e cinquenta e cinco de plantas. O índice de Sørensen, para avifauna, expressou um valor de similaridade de 0,65420 quando comparado a outros estudos; enquanto que o mesmo índice, para flora arbórea ficou na ordem de 0,37500. É necessário, desenvolvimento de ferramentas de sensibilização e transformação que promovam mudanças de conduta na comunidade do entorno

Main degradation products of dabigatran etexilate evaluated by LC-UV and LC-ESI-MS, degradation kinetics and in vitro cytotoxicity studies

The present study reports the stability profile of an antithrombotic drug: dabigatran etexilate (DAB). The drug was subjected to thermal degradation at 60 °C and products formed were investigated by liquid chromatography-UV (LC-UV) and liquid chromatography-mass spectrometry (LC-ESI-MS). Chromatographic separation of the degradation products was performed on a GL Sciences Inc. Inertsil ODS-2 column (250 mm × 4.6 mm i.d., with a particle size of 5 µm and pore size of 110 Å) with mobile phase consisting of acetonitrile and ammonium acetate buffer (pH 5.5; 10 mmol L−1 ) (65:35, v/v) pumped at 1.0 mL min−1 flow rate. Column temperature was set at 30 °C and detection at 225 nm using a UV detector. LC-UV method previously validated was extended to LC-ESI-MS for the characterization of the degradation products (DP-01 and DP-02) formed, without complicated isolation or purification processes, based on retention times and confirmation of molecular weight. Degradation kinetics of DAB was also evaluated and could be described as a first-order process (R2 = 0.9900). Furthermore, no evidence of cytotoxicity in human mononuclear cells was observed for DAB degraded samples

Protected areas and the neglected contribution of Indigenous Peoples and local communities: Struggles for environmental justice in the Caatinga dry forest

Despite evidence about the contribution of Indigenous Peoples and local communities (IPLCs) to conservation, prevailing strategies still seek their separation from nature, often triggering conflicts. Current pledges to expand global protected area coverage suggest a need for the critical analysis of governance quality and the way conservation interacts with the well-being of IPLCs. We present the case of Catimbau National Park in the Caatinga dry forest of northeast Brazil, where we explored connections between the well-being of IPLCs and landscape through different values, practices and institutions, and perceptions of how environmentally just the park's governance has been. The well-being of IPLCs is inextricably connected with the Caatinga landscape, through multiple place-based relational values that, although differing between Indigenous and non-indigenous inhabitants, have in both cases developed over generations. Although often framed as degraders, IPLCs exhibit a strong motivation to conserve, reflected through local institutions including forest gardens, sustainable use regulations, restoration activities and prevention of external encroachment. The strict form of protected area implemented at Catimbau, instead of a locally led or sustainable use reserve, explicitly targeted the resettlement of IPLCs and livelihood reorientation. These imposed objectives have clashed with a way of life in this peopled landscape and precluded local stewardship on a larger scale. Long-term conflict arose through governance deficiencies which sparked multidimensional injustices. These include not only the misrecognition of local values and customary institutions but also the lack of procedures for consent or decision-making influence, plus distributional harms including tenure insecurity and denied development assistance. Development and conservation strategies must reject narratives about poor, resource-dependent rural communities and embrace the opportunities that local knowledge and institutions bring for effective conservation. As conservation efforts are expanded post-2020, the people of the Caatinga and beyond must be recognised as embedded and a key part of any solution. In strict protected areas like Catimbau, where social conflict constrains their ability to function, seeking legal changes in governance type can be onerous. However, we describe other local-level actions to build relationships and agency that may foster transitions towards better governance, and just treatment of IPLCs. A free Plain Language Summary can be found within the Supporting Information of this article

Hexosamine Biosynthetic Pathway and Glycosylation Regulate Cell Migration in Melanoma Cells

The Hexosamine Biosynthetic Pathway (HBP) is a branch of glycolysis responsible for the production of a key substrate for protein glycosylation, UDP-GlcNAc. Cancer cells present altered glucose metabolism and aberrant glycosylation, pointing to alterations on HBP. Recently it was demonstrated that HBP influences many aspects of tumor biology, including the development of metastasis. In this work we characterize HBP in melanoma cells and analyze its importance to cellular processes related to the metastatic phenotype. We demonstrate that an increase in HBP flux, as well as increased O-GlcNAcylation, leads to decreased cell motility and migration in melanoma cells. In addition, inhibition of N- and O-glycosylation glycosylation reduces cell migration. High HBP flux and inhibition of N-glycosylation decrease the activity of metalloproteases 2 and 9. Our data demonstrates that modulation of HBP and different types of glycosylation impact cell migration

Pervasive gaps in Amazonian ecological research

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

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe