On the structure of acyclic binary relations

We investigate the structure of acyclic binary relations from different points of view. On the one hand, given a nonempty set we study real-valued bivariate maps that satisfy suitable functional equations, in a way that their associated binary relation is acyclic. On the other hand, we consider acyclic directed graphs as well as their representation by means of incidence matrices. Acyclic binary relations can be extended to the asymmetric part of a linear order, so that, in particular, any directed acyclic graph has a topological sorting.This work has been partially supported by the research projects MTM2012-37894-C02-02, TIN2013-47605-P, ECO2015-65031-R, MTM2015-63608-P (MINECO/FEDER), TIN2016-77356-P and the Research Services of the Public University of Navarre (Spain)

Sequestration of Martian CO2 by mineral carbonation

Carbonation is the water-mediated replacement of silicate minerals, such as olivine, by carbonate, and is commonplace in the Earth’s crust. This reaction can remove significant quantities of CO2 from the atmosphere and store it over geological timescales. Here we present the first direct evidence for CO2 sequestration and storage on Mars by mineral carbonation. Electron beam imaging and analysis show that olivine and a plagioclase feldspar-rich mesostasis in the Lafayette meteorite have been replaced by carbonate. The susceptibility of olivine to replacement was enhanced by the presence of smectite veins along which CO2-rich fluids gained access to grain interiors. Lafayette was partially carbonated during the Amazonian, when liquid water was available intermittently and atmospheric CO2 concentrations were close to their present-day values. Earlier in Mars’ history, when the planet had a much thicker atmosphere and an active hydrosphere, carbonation is likely to have been an effective mechanism for sequestration of CO2

The Effect of Nicotine on Reproduction and Attachment of Human Gingival Fibroblasts In Vitro

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142127/1/jper0658.pd

Climate Mitigation through Biological Conservation: Extensive and Valuable Blue Carbon Natural Capital in Tristan da Cunha’s Giant Marine Protected Zone

Carbon-rich habitats can provide powerful climate mitigation if meaningful protection is put in place. We attempted to quantify this around the Tristan da Cunha archipelago Marine Protected Area. Its shallows (&lt;1000 m depth) are varied and productive. The 5.4 km2 of kelp stores ~60 tonnes of carbon (tC) and may export ~240 tC into surrounding depths. In deep-waters we analysed seabed data collected from three research cruises, including seabed mapping, camera imagery, seabed oceanography and benthic samples from mini-Agassiz trawl. Rich biological assemblages on seamounts significantly differed to the islands and carbon storage had complex drivers. We estimate ~2.3 million tC are stored in benthic biodiversity of waters &lt;1000 m, which includes &gt;0.22 million tC that can be sequestered (the proportion of the carbon captured that is expected to become buried in sediment or locked away in skeletal tissue for at least 100 years). Much of this carbon is captured by cold-water coral reefs as a mixture of inorganic (largely calcium carbonate) and organic compounds. As part of its 2020 Marine Protection Strategy, these deep-water reef systems are now protected by a full bottom-trawling ban throughout Tristan da Cunha and representative no take areas on its seamounts. This small United Kingdom Overseas Territory’s reef systems represent approximately 0.8 Mt CO2 equivalent sequestered carbon; valued at &gt;£24 Million GBP (at the UN shadow price of carbon). Annual productivity of this protected standing stock generates an estimated £3 million worth of sequestered carbon a year, making it an unrecognized and potentially major component of the economy of small island nations like Tristan da Cunha. Conservation of near intact habitats are expected to provide strong climate and biodiversity returns, which are exemplified by this MPA.</jats:p

Can We Really Prevent Suicide?

Every year, suicide is among the top 20 leading causes of death globally for all ages. Unfortunately, suicide is difficult to prevent, in large part because the prevalence of risk factors is high among the general population. In this review, clinical and psychological risk factors are examined and methods for suicide prevention are discussed. Prevention strategies found to be effective in suicide prevention include means restriction, responsible media coverage, and general public education, as well identification methods such as screening, gatekeeper training, and primary care physician education. Although the treatment for preventing suicide is difficult, follow-up that includes pharmacotherapy, psychotherapy, or both may be useful. However, prevention methods cannot be restricted to the individual. Community, social, and policy interventions will also be essentia

Effect of neutrophil elastase and its inhibitor EPI-hNE4 on transepithelial sodium transport across normal and cystic fibrosis human nasal epithelial cells

<p>Abstract</p> <p>Background</p> <p>Hyperactivity of the epithelial sodium (Na⁺) channel (ENaC) and increased Na⁺absorption by airway epithelial cells leading to airway surface liquid dehydration and impaired mucociliary clearance are thought to play an important role in the pathogenesis of cystic fibrosis (CF) pulmonary disease. In airway epithelial cells, ENaC is constitutively activated by endogenous trypsin-like serine proteases such as Channel-Activating Proteases (CAPs). It was recently reported that ENaC activity could also be stimulated by apical treatment with human neutrophil elastase (hNE) in a human airway epithelial cell line, suggesting that hNE inhibition could represent a novel therapeutic approach for CF lung disease. However, whether hNE can also activate Na⁺reabsorption in primary human nasal epithelial cells (HNEC) from control or CF patients is currently unknown.</p> <p>Methods</p> <p>We evaluated by short-circuit current (<it>I</it>_sc) measurements the effects of hNE and EPI-hNE4, a specific hNE inhibitor, on ENaC activity in primary cultures of HNEC obtained from control (9) and CF (4) patients.</p> <p>Results</p> <p>Neither hNE nor EPI-hNE4 treatments did modify <it>I</it>_scin control and CF HNEC. Incubation with aprotinin, a Kunitz-type serine protease inhibitor that blocks the activity of endogenous CAPs, decreased <it>I</it>_scby 27.6% and 54% in control and CF HNEC, respectively. In control and CF HNEC pretreated with aprotinin, hNE did significantly stimulate <it>I</it>_sc, an effect which was blocked by EPI-hNE4.</p> <p>Conclusions</p> <p>These results indicate that hNE does activate ENaC and transepithelial Na⁺transport in both normal and CF HNEC, on condition that the activity of endogenous CAPs is first inhibited. The potent inhibitory effect of EPI-hNE4 on hNE-mediated ENaC activation observed in our experiments highlights that the use of EPI-hNE4 could be of interest to reduce ENaC hyperactivity in CF airways.</p

Political Dimensions of Environmental Citizenship

Conceptions of Environmental Citizenship are core to models of sustainability. Such contested conceptions raise historically significant questions associated with the rights of the individual and the responsibility of the community to the environment. Attitudes towards sustainability beg questions of models of citizenship ranging from compliance through democratic deliberation to active dissent. Philosophical problems also intersect with Environmental Citizenship. Ecocentrism prioritises a systemic holistic view of Nature in which the human species has no privileged role. Anthropocentrism in its more liberal aspect has an instrumental view of Nature underpinned by beneficence. These divergent ideologies also presuppose metaphysical and ontological questions about the relationship between Mind and Nature, hence fundamental implications for education and citizenship more broadly. There are, of course, intermediate positions. This raises three driving questions: 1. What are the main philosophical and political positions associated with Environmental Citizenship? 2. What are the justifications underpinning particular approaches to Environmental Citizenship? 3. Can we map the main components of Environmental Citizenship to create a coherent European and Global approach to inquiry

Elevated Plasma Von Willebrand Factor and Propeptide Levels in Malawian Children with Malaria

In children with malaria plasma VWF and propeptide levels are markedly elevated in both cerebral and mild paediatric malaria, with levels matching disease severity, and these normalize upon recovery. High levels of both markers also occur in retinopathy-negative 'cerebral malaria' cases, many of whom are thought to be suffering from diseases other than malaria, indicating that further studies of these markers will be required to determine their sensitivity and specificity