2,515 research outputs found
Hydroclimate variability was the main control on fire activity in northern Africa over the last 50,000 years
North Africa features some of the most frequently burnt biomes on Earth, including the semi-arid grasslands of the Sahel and wetter savannas immediately to the south. Natural fires are fuelled by rapid biomass production during the wet season, its desiccation during the dry season and ignition by frequent dry lightning strikes. Today, fire activity decreases markedly both to the north of the Sahel, where rainfall is extremely low, almost eliminating biomass over the Sahara, and to the south where forest biomes are too wet to burn. Over the last glacial cycle, rainfall and vegetation cover over northern Africa varied dramatically in response to gradual astronomically-forced insolation change, changes in atmospheric carbon dioxide levels, and abrupt cooling events over the North Atlantic Ocean associated with the reorganisation of Meridional Overturning Circulation (MOC). Here we report the results of a study into the impact of these climate changes on fire activity in northern African over the last 50,000 years (50 kyr). Our reconstructions come from marine sediments with strong age control that provide an uninterrupted record of charcoal particles exported from the African continent. We studied three sites on a latitudinal transect along the northwest African margin between 21 and 9°N. Our sites exhibit a distinct latitudinal relationship between past changes in rainfall and fire activity. At the southernmost site (GeoB9528-3, 9°N), fire activity decreased during intervals of increasing humidity, while our northernmost site (ODP Site 658, 21°N) clearly demonstrates the opposite relationship. The site in the middle of our transect, offshore of the present day southern Sahel today (GeoB9508-5, 15°N), exhibits a “Goldilocks” relationship between fire activity and hydroclimate, wherein charcoal fluxes peak under intermediate rainfall climate conditions and are supressed by transition to more arid or more humid conditions. Our results are remarkably consistent with the predictions of the intermediate fire-productivity hypothesis developed in conceptual macroecological models and supported by empirical evidence of modern day fire activity. Feedback processes operating between fire, climate and vegetation are undoubtedly complex but temperature is suggested to be the main driver of temporal change in fire activity globally, with the precipitation-evaporation balance perhaps a secondary influence in the Holocene tropics. However, there is only sparse coverage of Africa in the composite records upon which those interpretations are based. We conclude that hydroclimate (not temperature) exerted the dominant control on burning in the tropics of northern Africa well before the Holocene (from at least 50 ka).publishedVersio
Smoking, alcohol consumption, diet and physical activity following stoma formation surgery, stoma-related concerns, and desire for lifestyle advice: a United Kingdom survey
Background Adherence to smoking, alcohol consumption, diet and physical activity (PA) guidelines may improve outcomes for people with a stoma. A better understanding of these behaviours following stoma formation surgery and their experiences and attitudes towards receiving lifestyle advice, could help identify specific gaps and inform interventions going forward. The aim of this study was to describe changes in current lifestyle following stoma formation and to explore concerns, desire for lifestyle information, advice and support among people who have or have had a stoma.Methods A sample of adults who currently had or in the past had a stoma for treatment for any medical condition was recruited online through relevant charities and companies, and invited to complete a cross-sectional, online survey. Consenting participants (n = 425) provided demographic information and completed brief, validated questionnaires about their lifestyle, alongside questions around their concerns regarding permanent stoma and experiences of lifestyle information and advice. Responses were summarised using descriptive statistics, and associations between reported concerns about stoma and changes in health behaviours were explored.Results Most respondents (93%) still had a stoma at the time of completing the survey. The majority (80%) had not consumed at least 5 portions of fruit and vegetables on the previous day and 20% reported they had not participated in at least 30 min of physical activity on any day in the previous week. Most respondents were non-smokers (84%) and did not exceed recommendations for alcohol intake (60%). Most (56%) felt their PA had decreased following stoma formation. Frequencies of concerns about a permanent stoma were high, and appeared to be associated with reported decreases in PA. Of those reporting nausea, 40% felt their diet had worsened since having their stoma. A large proportion of respondents had not received PA (42%) or dietary (30%) advice, and of these > 90% would have liked guidance.Conclusions Few respondents to this survey were eating the recommended amount of fruit and vegetables, and most reported a decrease in their PA following stoma surgery. Lifestyle advice would be welcomed by this population, which professionals should take into account when addressing stoma- related concerns
Protocol of a systematic review and network meta-analysis for the prevention and treatment of perinatal depression
Introduction Perinatal depression is common and can often lead to adverse health outcomes for mother and child. Multiple pharmacological and non-pharmacological treatments have been evaluated against usual care or placebo controls in meta-analyses for preventing and treating perinatal depression compared. It is not yet established which of these candidate treatments might be the optimal approach for prevention or treatment. Methods and analysis A systematic review and Bayesian network meta-analyses will be conducted. Eight electronic databases shall be searched for randomised controlled trials that have evaluated the effectiveness of treatments for prevention and/or treatment of perinatal depression. Screening of articles shall be conducted by two reviewers independently. One network meta-analysis shall evaluate the effectiveness of interventions in preventing depression during the perinatal period. A second network meta-analysis shall compare the effectiveness of treatments for depression symptoms in women with perinatal depression. Bayesian 95% credible intervals shall be used to estimate the pooled mean effect size of each treatment, and surface under cumulative ranking area will be used to rank the treatments\u27 effectiveness. Ethics and dissemination We shall report our findings so that healthcare providers can make informed decisions on what might be the optimal approach for addressing perinatal depression to prevent cases and improve outcomes in those suffering from depression through knowledge exchange workshops, international conference presentations and journal article publications. PROSPERO registration number CRD42020200081
Long-term trial of protection provided by adenovirus-vectored vaccine expressing the PPRV H protein
A recombinant, replication-defective, adenovirus-vectored vaccine expressing the H surface glycoprotein of peste des petits ruminants virus (PPRV) has previously been shown to protect goats from challenge with wild-type PPRV at up to 4 months post vaccination. Here, we present the results of a longer-term trial of the protection provided by such a vaccine, challenging animals at 6, 9, 12 and 15 months post vaccination. Vaccinated animals developed high levels of anti-PPRV H protein antibodies, which were virus-neutralising, and the level of these antibodies was maintained for the duration of the trial. The vaccinated animals were largely protected against overt clinical disease from the challenge virus. Although viral genome was intermittently detected in blood samples, nasal and/or ocular swabs of vaccinated goats post challenge, viral RNA levels were significantly lower compared to unvaccinated control animals and vaccinated goats did not appear to excrete live virus. This protection, like the antibody response, was maintained at the same level for at least 15 months after vaccination. In addition, we showed that animals that have been vaccinated with the adenovirus-based vaccine can be revaccinated with the same vaccine after 12 months and showed an increased anti-PPRV antibody response after this boost vaccination. Such vaccines, which provide a DIVA capability, would therefore be suitable for use when the current live attenuated PPRV vaccines are withdrawn at the end of the ongoing global PPR eradication campaign
Reduction chemistry yields stable and soluble divalent lanthanide tris(pyrazolyl)borate complexes â€
Reduction of the heteroleptic Ln(iii) precursors [Ln(Tp)2(OTf)] (Tp = hydrotris(1-pyrazolyl)borate; OTf = triflate) with either an aluminyl(i) anion or KC8 yielded the adduct-free homoleptic Ln(ii) complexes dimeric 1-Eu [{Eu(Tp)(μ-κ1:η5-Tp)}2] and monomeric 1-Yb [Yb(Tp)2]. Complexes 1-Ln have good solubility and stability in both non-coordinating and coordinating solvents. Reaction of 1-Ln with 2 Ph3PO yielded 1-Ln(OPPh3)2. All complexes are intensely coloured and 1-Eu is photoluminescent. The electronic absorption data show the 4f–5d electronic transitions in Ln(ii). Single-crystal X-ray diffraction data reveal first μ-κ1:η5-coordination mode of the unsubstituted Tp ligand to lanthanides in 1-Eu
The oceanography and marine ecology of Ningaloo, a world heritage area
The Ningaloo coast of north-western Australia (eastern Indian Ocean) hosts one of the world’s longest and most extensive fringing coral reef systems, along with globally significant abundances of large marine fauna such as whale sharks. These characteristics – which have contributed to its inscription on the World Heritage list – exist because of the unique climatic, geomorphologic and oceanographic conditions. The region is hot and arid, so runoff of water from land is low, facilitating clear water that allows corals to grow close to the shore. The poleward-flowing Leeuwin Current is an important influence, bringing warm water and generally suppressing coastal upwelling. During the austral summer, strong southerly winds generate the equatorward-flowing Ningaloo Current on the inner shelf – this current facilitates sporadic upwelling events that enhance concentrations of nutrients, which in turn enhance pelagic primary productivity that supports the reef’s biota. The coast has experienced several marine heatwaves since 2011 that have caused mortality of corals and probably seagrass, albeit relatively less than elsewhere along the coast. Wind-generated surface waves break over the fringing reef crest, causing cooling currents that tend to dampen warming – although this mechanism seems not to have prevented some areas from experiencing damaging heat, and corals in places that do not receive the wave-generated currents have experienced substantial mortality. Herbivores, from fish to green turtles, are abundant, and in the lagoon, extensive stands of large brown algae provide an important habitat for newly recruited fish. There has been a decline in abundance of some fish. Predictions of future pressures include a weaker but more variable Leeuwin Current and increased human use. The ability of Ningaloo’s ecosystems to withstand growing pressures will depend partly on the rate and magnitude of global warming but also on actions that manage local pressures from increasing human use. These actions will rely on continued science to provide the evidence needed to identify the pressures, the changes they create and the ways that we can mitigate them
Smoking, alcohol consumption, diet and physical activity following stoma formation surgery, stoma-related concerns, and desire for lifestyle advice: a United Kingdom survey
Background:Adherence to smoking, alcohol consumption, diet and physical activity (PA) guidelines may improve outcomes for people with a stoma. A better understanding of these behaviours following stoma formation surgery and their experiences and attitudes towards receiving lifestyle advice, could help identify specific gaps and inform interventions going forward. The aim of this study was to describe changes in current lifestyle following stoma formation and to explore concerns, desire for lifestyle information, advice and support among people who have or have had a stoma.Methods:A sample of adults who currently had or in the past had a stoma for treatment for any medical condition was recruited online through relevant charities and companies, and invited to complete a cross-sectional, online survey. Consenting participants (n?=?425) provided demographic information and completed brief, validated questionnaires about their lifestyle, alongside questions around their concerns regarding permanent stoma and experiences of lifestyle information and advice. Responses were summarised using descriptive statistics, and associations between reported concerns about stoma and changes in health behaviours were explored.Results:Most respondents (93%) still had a stoma at the time of completing the survey. The majority (80%) had not consumed at least 5 portions of fruit and vegetables on the previous day and 20% reported they had not participated in at least 30?min of physical activity on any day in the previous week. Most respondents were non-smokers (84%) and did not exceed recommendations for alcohol intake (60%). Most (56%) felt their PA had decreased following stoma formation. Frequencies of concerns about a permanent stoma were high, and appeared to be associated with reported decreases in PA. Of those reporting nausea, 40% felt their diet had worsened since having their stoma. A large proportion of respondents had not received PA (42%) or dietary (30%) advice, and of these >?90% would have liked guidance.Conclusions:Few respondents to this survey were eating the recommended amount of fruit and vegetables, and most reported a decrease in their PA following stoma surgery. Lifestyle advice would be welcomed by this population, which professionals should take into account when addressing stoma- related concerns
Chapter 4 The Oceanography and Marine Ecology of Ningaloo, A World Heritage Area
The Ningaloo coast of north-western Australia (eastern Indian Ocean) hosts one of the world’s longest and most extensive fringing coral reef systems, along with globally-significant abundances of large marine fauna such as whale sharks. These characteristics — which have contributed to its inscription on the World Heritage list — exist because of the unique climatic, geomorphologic and oceanographic conditions. The region is hot and arid, so runoff of water from land is low, facilitating clear water that allows corals to grow close to the shore. The poleward-flowing Leeuwin Current is an important influence, bringing warm water and generally suppressing coastal upwelling. During the austral summer, strong southerly winds generate the equatorward-flowing Ningaloo Current on the inner shelf — this current facilitates sporadic upwelling events that enhance concentrations of nutrients, which in turn enhances pelagic primary productivity that supports the reef’s biota. The coast has experienced several marine heatwaves since 2011 that have caused mortality of corals, and probably seagrass, albeit relatively less than elsewhere along the coast. Wind-generated surface waves break over the fringing reef crest, causing cooling currents that tend to dampen warming — although this mechanism seems not to have prevented some areas from experiencing damaging heat, and corals in places that do not experience the wave-generated currents have experienced substantial mortality. Herbivores, from fish to green turtles, are abundant, and in the lagoon extensive stands of large brown algae provide an important habitat for newly-recruited fish. There has been a decline in abundance of some fish. Predictions of future pressures include a weaker but more variable Leeuwin Current, and increased human use. The ability of Ningaloo’s ecosystems to withstand growing pressures will depend partly on the rate and magnitude of global warming, but also on actions that manage local pressures from increasing human use. These actions will rely on continued science to provide the evidence needed to identify the pressures, the changes they create and the ways that we can mitigate them
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