BACKGROUND: Botanists, ecologists and evolutionary biologists are familiar with the astonishing species richness and endemism of the fynbos of the Cape Floristic Region and the ancient and unique ...flora of the kwongkan of south-western Australia. These regions represent old climatically-buffered infertile landscapes (OCBILs) that are the basis of a general hypothesis to explain their richness and endemism. However, few ecologists are familiar with the campo rupestre of central and eastern Brazil, an extremely old mountaintop ecosystem that is both a museum of ancient lineages and a cradle of continuing diversification of endemic lineages. SCOPE: Diversification of some lineages of campo rupestre pre-dates diversification of lowland cerrado, suggesting it may be the most ancient open vegetation in eastern South America. This vegetation comprises more than 5000 plant species, nearly 15 % of Brazil’s plant diversity, in an area corresponding to 0.78 % of its surface. Reviewing empirical data, we scrutinise five predictions of the OCBIL theory, and show that campo rupestre is fully comparable to and remarkably convergent with both fynbos and kwongkan, and fulfills the criteria for a classic OCBIL. CONCLUSIONS: The increasing threats to campo rupestre are compromising ecosystem services and we argue for the implementation of more effective conservation and restoration strategies.
ABSTRACT
Despite growing recognition of the conservation values of grassy biomes, our understanding of how to maintain and restore biodiverse tropical grasslands (including savannas and open‐canopy ...grassy woodlands) remains limited. To incorporate grasslands into large‐scale restoration efforts, we synthesised existing ecological knowledge of tropical grassland resilience and approaches to plant community restoration. Tropical grassland plant communities are resilient to, and often dependent on, the endogenous disturbances with which they evolved – frequent fires and native megafaunal herbivory. In stark contrast, tropical grasslands are extremely vulnerable to human‐caused exogenous disturbances, particularly those that alter soils and destroy belowground biomass (e.g. tillage agriculture, surface mining); tropical grassland restoration after severe soil disturbances is expensive and rarely achieves management targets. Where grasslands have been degraded by altered disturbance regimes (e.g. fire exclusion), exotic plant invasions, or afforestation, restoration efforts can recreate vegetation structure (i.e. historical tree density and herbaceous ground cover), but species‐diverse plant communities, including endemic species, are slow to recover. Complicating plant‐community restoration efforts, many tropical grassland species, particularly those that invest in underground storage organs, are difficult to propagate and re‐establish. To guide restoration decisions, we draw on the old‐growth grassland concept, the novel ecosystem concept, and theory regarding tree cover along resource gradients in savannas to propose a conceptual framework that classifies tropical grasslands into three broad ecosystem states. These states are: (1) old‐growth grasslands (i.e. ancient, biodiverse grassy ecosystems), where management should focus on the maintenance of disturbance regimes; (2) hybrid grasslands, where restoration should emphasise a return towards the old‐growth state; and (3) novel ecosystems, where the magnitude of environmental change (i.e. a shift to an alternative ecosystem state) or the socioecological context preclude a return to historical conditions.
•Road accidents are one of the major causes of death in the world.•Motorcyclists are less protected when compared to users of some other vehicles, such as car occupants.•Rotational acceleration is a ...mechanism of severe head injuries.•Currently, motorcycle helmet standards do not access rotational acceleration.•Finite Element Method is useful to reconstruct real accidents and predict head injuries.
This paper tries to make an overview of the work carried out by scientific community in the area of road helmets safety. In an area that is constantly being pushed forward by market competition, self-awareness of danger and tighter standards, several research groups around the world have contributed to safety gear improvement.
In this work concepts related to head impact protection and energy absorption are explained. It also makes reference to the theories related to the development of helmets, as well as to the different existing types nowadays. The materials that are typically used in impact situations and new design concepts are also approached. In addition, it is presented a literature review of current – and most commonly used – helmet test standards, along with new tests and helmet concepts to assess the effects of rotational motion.
In a non-restrictive, and never up-to-date report, a state-of-art review on road helmets safety is done, with a special insight into brain injury, helmet design and standards.
Cork composites are byproducts from wine stopper production, resulting from the agglomeration of cork granules with a thermoset resin. The resulting compound is a versatile and durable material with ...numerous industrial applications. Due to its unique properties, such as low-density, high-strength, excellent energy absorption, and good thermal and acoustic insulators, cork composites find room for application in demanding industries such as automotive, construction, and aerospace. However, agglomerated cork typically has a polyurethane matrix derived from petrochemical sources. This study focuses on developing eco-friendly porous polyurethane biocomposites manufactured with the used cooking oil polyol modified with cork. Since cork and polyurethane foam are typically used for impact shock absorption, the manufactured samples were subjected to impact loading. The assessment of crashworthiness is performed through 100 J impact tests. A finite element numerical model was developed to simulate the compression of these new composites under impact, and the model validation was performed. The highest specific absorbed energy was obtained for petrochemical polyol composites with the 3% addition of natural or modified cork. The research conducted in this study showcased the feasibility of substituting certain petrochemical components used for the synthesis of the polyurethane matrix with ecological waste vegetable oil components.
IMPORTANCE: Acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 (COVID-19) is associated with substantial mortality and use of health care resources. Dexamethasone use might ...attenuate lung injury in these patients. OBJECTIVE: To determine whether intravenous dexamethasone increases the number of ventilator-free days among patients with COVID-19–associated ARDS. DESIGN, SETTING, AND PARTICIPANTS: Multicenter, randomized, open-label, clinical trial conducted in 41 intensive care units (ICUs) in Brazil. Patients with COVID-19 and moderate to severe ARDS, according to the Berlin definition, were enrolled from April 17 to June 23, 2020. Final follow-up was completed on July 21, 2020. The trial was stopped early following publication of a related study before reaching the planned sample size of 350 patients. INTERVENTIONS: Twenty mg of dexamethasone intravenously daily for 5 days, 10 mg of dexamethasone daily for 5 days or until ICU discharge, plus standard care (n =151) or standard care alone (n = 148). MAIN OUTCOMES AND MEASURES: The primary outcome was ventilator-free days during the first 28 days, defined as being alive and free from mechanical ventilation. Secondary outcomes were all-cause mortality at 28 days, clinical status of patients at day 15 using a 6-point ordinal scale (ranging from 1, not hospitalized to 6, death), ICU-free days during the first 28 days, mechanical ventilation duration at 28 days, and Sequential Organ Failure Assessment (SOFA) scores (range, 0-24, with higher scores indicating greater organ dysfunction) at 48 hours, 72 hours, and 7 days. RESULTS: A total of 299 patients (mean SD age, 61 14 years; 37% women) were enrolled and all completed follow-up. Patients randomized to the dexamethasone group had a mean 6.6 ventilator-free days (95% CI, 5.0-8.2) during the first 28 days vs 4.0 ventilator-free days (95% CI, 2.9-5.4) in the standard care group (difference, 2.26; 95% CI, 0.2-4.38; P = .04). At 7 days, patients in the dexamethasone group had a mean SOFA score of 6.1 (95% CI, 5.5-6.7) vs 7.5 (95% CI, 6.9-8.1) in the standard care group (difference, −1.16; 95% CI, −1.94 to −0.38; P = .004). There was no significant difference in the prespecified secondary outcomes of all-cause mortality at 28 days, ICU-free days during the first 28 days, mechanical ventilation duration at 28 days, or the 6-point ordinal scale at 15 days. Thirty-three patients (21.9%) in the dexamethasone group vs 43 (29.1%) in the standard care group experienced secondary infections, 47 (31.1%) vs 42 (28.3%) needed insulin for glucose control, and 5 (3.3%) vs 9 (6.1%) experienced other serious adverse events. CONCLUSIONS AND RELEVANCE: Among patients with COVID-19 and moderate or severe ARDS, use of intravenous dexamethasone plus standard care compared with standard care alone resulted in a statistically significant increase in the number of ventilator-free days (days alive and free of mechanical ventilation) over 28 days. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04327401
Comment on “The global tree restoration potential” Veldman, Joseph W.; Aleman, Julie C.; Alvarado, Swanni T. ...
Science (American Association for the Advancement of Science),
10/2019, Letnik:
366, Številka:
6463
Journal Article, Web Resource
Recenzirano
Odprti dostop
Bastin
et al
.’s estimate (Reports, 5 July 2019, p. 76) that tree planting for climate change mitigation could sequester 205 gigatonnes of carbon is approximately five times too large. Their analysis ...inflated soil organic carbon gains, failed to safeguard against warming from trees at high latitudes and elevations, and considered afforestation of savannas, grasslands, and shrublands to be restoration.
One of the most severe traumatic brain injuries, the subdural haematoma, is related to damage and rupture of the bridging veins, generating an abnormal collection of blood between the dura mater and ...arachnoid mater. Current numerical models of these vessels rely on very simple geometries and material laws, limiting its accuracy and bio-fidelity.
In this work, departing from an existing human head numerical model, a realistic geometry for the bridging veins was developed, devoting special attention to the finite elements type employed. A novel and adequate constitutive model including damage behavior was also successfully implemented.
Results attest that vessel tearing onset was correctly captured, after comparison against experiments on cadavers.
Doing so, the model allow to precisely predict the individual influence of kinematic parameters such as the pulse duration, linear and rotational accelerations in promoting vessel tearing.
•Detailed numerical modeling of the superior sagittal sinus and 9 pairs of bridging veins•Constitutive modeling including elasto-plasticity and ductile damage•Integration into a finite element head model and validation against experiments on cadavers
Advances in methodologies to evaluate biomaterials brought an explosive growth of data, ensuing computational challenges to better analyzing them and allowing for high-throughput profiling of ...biological systems cost-efficiently. In this sense, we have applied bioinformatics tools to better understand the biological effect of different sintering temperatures of hydroxyapatite (abbreviated HA; at 1100, 1150, and 1250°C) on osteoblast performance. To do, we have better analyzed an earlier deposited study, in which the access code is E-MTAB-7219, which the authors have explored different in silico tools on this purpose. In this study, differential gene expression analyses were performed using the gene set variation analysis (GSVA) algorithm from the transcriptomes respecting the thermal changes of HA, which were validated using exclusively in vitro strategies. Furthermore, in silico approaches elected biomarkers during cell behavior in response to different sintering temperatures of HA, and it was further validated using cell culture and qPCR technologies. Altogether, the combination of those strategies shows the capacity of sintered HA at 1250°C to present a better performance in organizing an adequate microenvironment favoring bone regeneration, angiogenesis and material resorption stimulus once it has promoted higher involvement of genes such as CDK2, CDK4 (biomarkers of cell proliferation), p15, Osterix gene (related with osteogenic differentiation), RANKL (related with osteoclastogenesis), VEGF gene (related with angiogenesis), and HIF1α (related with hypoxia microenvironment). Altogether, the combination of in silico and cell culture strategies shows the capacity of sintered HA at 1250°C in guaranteeing osteoblast differentiation and it can be related in organizing an adequate microenvironment favoring bone regeneration, angiogenesis, and material resorption stimulus.
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•A review of e-micromobility solutions and their impact on urban mobility.•An overview on injuries among EMM users, with focus on head injuries.•A critical review of the head ...protective gear available for EMM users.•Wearing a helmet for spontaneous riders was found to be inconvenient in many ways.•Helmets design for e-scooters should be aligned with this concept of transportation.
Traffic jams are a burden in urban areas, being time-consuming and contributing to stressful driving and CO2 emissions. To implement the United Nations’ 2030 agenda for sustainable development, governmental strategies aim to accelerate the shift to sustainable and smart mobility. Consequently, e-micromobility (EMM) appeared as a practical solution for short-distance commuters, and it is growing at upsetting rates thanks to the introduction of sharing services. In fact, urban mobility has drastically changed over the last decade, and electric mobility and micromobility changed the panorama in larger metropolises, given their accessibility, large availability, and the potential to be a time saver in short trips and a potentially sustainable alternative in particular scenarios. The downside of portable e-transportation is the rapid increase in injuries and fatalities. Focusing on standing e-scooters, head injuries are becoming one of the most common as shown by research conducted in different urban emergency departments, alongside bone fractures, skin abrasions, and lacerations. In this work, a comprehensive review is carried out focusing on head protection for EMM, mostly for e-scooters, and the respective target markets, safety measures, and existing regulations. In the end, a critical assessment is given with recommendations for legislators and future research. Users are mostly males from 18 to 40 years old, upper-to-middle income, with elevated levels of educational attainment. Their motivation to use e-scooters is mainly to replace short walking trips. EMM, in particular e-scooters, will continue to grow thanks to its potential to substitute other micromobility alternatives. The evolution of safety measures and regulations did not keep pace with such a drastic change in mobility trends. This is evident considering how some countries are struggling with vehicle categories and regulations for helmet use and testing. The lack of legal obligation to wear a helmet and the absence of an adequate and feasible concept of protective equipment for sharing services are the main barriers to helmet use among riders. Mitigation measures have been implemented by the EMM sharing companies to improve the safety of its users by checking if they wear helmets and by offering vehicle-integrated solutions.
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