A historian probes the cultural contexts of our enduring fascination with the red planet.
AssuntosMarte , Planetas , Humanos , Meio Ambiente Extraterreno
BACKGROUND: There are strong links between the rise in unhealthy diets and non-communicable diseases, which are a major cause of morbidity and mortality in the community and have a strong impact on the health system. The current food system encourages poor food choices and fails to help many people follow the principles set out in the Australian Dietary Guidelines. There is also good evidence that healthier diets are likely to be more environmentally sustainable than the typical Australian diet. OBJECTIVE: New diets are constantly appearing, and it can be a confusing area for doctors and patients to make sense of their benefit. This paper aims to provide evidence that GPs can use to support healthier diets for their patients. DISCUSSION: General practitioners can provide education and motivation for patients to change their dietary patterns. This will involve choosing more healthy plant foods, with fewer highly processed products and less red meat, as currently recommended in the Australian Dietary Guidelines. Such dietary choices provide proven co-benefits for health and the environment.
AssuntosDieta , Planetas , Humanos , Austrália , Dieta Saudável , Política Nutricional
The Committee on Space Research's (COSPAR) Planetary Protection Policy states that all types of missions to Venus are classified as Category II, as the planet has significant research interest relative to the processes of chemical evolution and the origin of life, but there is only a remote chance that terrestrial contamination can proliferate and compromise future investigations. "Remote chance" essentially implies the absence of environments where terrestrial organisms could survive and replicate. Hence, Category II missions only require simplified planetary protection documentation, including a planetary protection plan that outlines the intended or potential impact targets, brief Pre- and Post-launch analyses detailing impact strategies, and a Post-encounter and End-of-Mission Report. These requirements were applied in previous missions and are foreseen for the numerous new international missions planned for the exploration of Venus, which include NASA's VERITAS and DAVINCI missions, and ESA's EnVision mission. There are also several proposed missions including India's Shukrayaan-1, and Russia's Venera-D. These multiple plans for spacecraft coincide with a recent interest within the scientific community regarding the cloud layers of Venus, which have been suggested by some to be habitable environments. The proposed, privately funded, MIT/Rocket Lab Venus Life Finder mission is specifically designed to assess the habitability of the Venusian clouds and to search for signs of life. It includes up to three atmospheric probes, the first one targeting a launch in 2023. The COSPAR Panel on Planetary Protection evaluated scientific data that underpins the planetary protection requirements for Venus and the implications of this on the current policy. The Panel has done a thorough review of the current knowledge of the planet's conditions prevailing in the clouds. Based on the existing literature, we conclude that the environmental conditions within the Venusian clouds are orders of magnitude drier and more acidic than the tolerated survival limits of any known terrestrial extremophile organism. Because of this future orbital, landed or entry probe missions to Venus do not require extra planetary protection measures. This recommendation may be revised in the future if new observations or reanalysis of past data show any significant increment, of orders of magnitude, in the water content and the pH of the cloud layer.
AssuntosMarte , Voo Espacial , Vênus , Planetas , Meio Ambiente Extraterreno , Contenção de Riscos Biológicos , Exobiologia
AssuntosClima , Planetas , Humanos , Mudança Climática
The definition of Just Transition in recent years has been shaped by the political and ideological leanings of multiple stakeholders. Labor movements look at a Just Transition that secures workers' rights and jobs; environmental justice groups include whole communities impacted by fossil fuel in their description; multilateral institutions, investors, and transnational corporations see it through lenses of economics, financial support, and investment. However, a perspective on health is missing in all these approaches. The COVID-19 pandemic has established the importance of health-based planning, making evident the co-dependence of ecological health and human well-being. The debilitating post-pandemic economic crisis has reiterated the interlinkage between economics, public health, and the environment. This document posits that health is the overlapping but missing link between the different movements' dream for Just Transition into an equitable world, and to heal people and the planet damaged by fossil fuels. We need Just Transition that has holistic health systems and accessible healthcare services at its core.
AssuntosCOVID-19 , Planetas , Humanos , Pandemias , COVID-19/epidemiologia , Saúde Pública , Combustíveis Fósseis
To date, several exoplanets have been found to orbit within the habitable zone of main sequence M stars (M dwarfs). These stars exhibit different levels of chromospheric activity that produces ultraviolet (UV) radiation. UV may be harmful to life, but it can also trigger reactions of prebiotic importance on the surface of a potentially habitable planet (PHP). We created a code to obtain the adenine yield for a known adenine synthesis route from diaminomaleonitrile (DAMN). We used computational methods to calculate the reaction coefficient rates (photolysis rate J and rate constant K) for the intermediate molecules DAMN, diaminofumaronitrile (DAFN), and 4-aminoimidazole-5-carbonitrile (AICN) of the adenine synthesis route. We used stellar UV sources and a mercury lamp to compare the theoretical results with experiments performed with lamps. The surface UV flux of planets in the habitable zone of two active M dwarfs (Proxima Centauri and AD Leonis) and the prebiotic Earth was calculated using the photochemical model ATMOS, considering a CO2-N2-H2O atmosphere. We obtained UV absorption coefficients for DAMN and DAFN and thermodynamic parameters that are useful for prebiotic chemistry studies. According to our results, experiments using UV lamps may underestimate the photolysis production of molecules of prebiotic importance. Our results indicate that photolysis reactions are fast with a yield of 50% of AICN in 10 s for the young Sun and â¼1 h for Proxima Centauri b. Planets around active M dwarfs may provide the most favorable environment for UV-mediated production of compounds relevant to the origins of life. The kinetic reaction AICN + HCN ï adenine is the bottleneck of the pathway with reaction rates <10-22 L/(mol·s).
AssuntosMeio Ambiente Extraterreno , Raios Ultravioleta , Meio Ambiente Extraterreno/química , Exobiologia/métodos , Planetas , Atmosfera/química
In this work, the viability of the detection of methane produced by microbial activity in low-temperature hydrothermal vents on an Archean-Earth-like exoplanet in the habitable zone is explored via a simplified bottom-up approach using a toy model. By simulating methanogens at hydrothermal vent sites in the deep ocean, biological methane production for a range of substrate inflow rates was determined and compared to literature values. These production rates were then used, along with a range of ocean floor vent coverage fractions, to determine likely methane concentrations in the simplified atmosphere. At maximum production rates, a vent coverage of 4-15 × 10-4 % (roughly 2000-6500 times that of modern Earth) is required to achieve 0.25% atmospheric methane. At minimum production rates, 100% vent coverage is not enough to produce 0.25% atmospheric methane. NASA's Planetary Spectrum Generator was then used to assess the detectability of methane features at various atmospheric concentrations. Even with future space-based observatory concepts (such as LUVOIR and HabEx), our results show the importance of both mirror size and distance to the observed planet. Planets with a substantial biomass of methanogens in hydrothermal vents can still lack a detectable, convincingly biological methane signature if they are beyond the scope of the chosen instrument. This work shows the value of coupling microbial ecological modeling with exoplanet science to better understand the constraints on biosignature gas production and its detectability.
AssuntosFontes Hidrotermais , Planetas , Meio Ambiente Extraterreno , Exobiologia , Temperatura , Metano
AssuntosSaúde Única , Planetas , Saúde Global
The health of the planet is one objective of the United Nations' Sustainable Development Goals. Vaccines can affect not only human health but also planet health by reducing poverty, preserving microbial diversity, reducing antimicrobial resistance, and preventing an increase in pandemics that is fueled partly by climate change.
AssuntosPlanetas , Vacinas , Humanos , Pandemias
We can use photosynthesis to capture carbon and make industries greener. Algae-driven carbon capture and manufacturing offer the potential for reducing CO2 emissions while also producing commodities such as bioplastics.
AssuntosDióxido de Carbono , Planetas , Indústrias , Comércio , Carbono
We urgently need solutions to make our use of the planet's resources more sustainable and protect nature. A new collection of articles outlines a vision for a better tomorrow that draws on new advances in the development of green technologies.
AssuntosPlanetas , Tecnologia
Cycling has many benefits for humans and the planet. This research investigates perceived norms and driver behavior toward cyclists as issues that may be useful for addressing reluctance to cycle. It connects perceived norms observed in the road context regarding aggressive driver behavior towards cyclists, and norms observed in workplaces regarding sustainability (perceived green psychological workplace climate) with driver aggressive behavior toward cyclists. Self-reported online survey responses from N = 426 Australian drivers were collected. Perceived norms regarding aggressive driver behavior toward cyclists were linked to drivers engaging more frequently in such behavior, but no such link was found for perceived green psychological workplace climate. However, perceived green psychological workplace climate moderated the link between perceived norms regarding aggressive driver behavior toward cyclists and drivers engaging in such behavior. When drivers perceived aggression toward cyclists to be common on the road, perceived green psychological workplace climate weakened the link between perceived norms regarding aggressive driver behavior towards cyclists and drivers engaging in such behavior. Findings reinforce the role of perceived road context norms regarding aggressive driver behavior toward cyclists for drivers engaging in such behavior. They illustrate that, while not directly linked, sustainability norms perceived in other contexts have a role in shaping car driver behavior towards cyclists. The study's findings suggest that interventions targeted at aggressive behavior toward cyclists in road contexts can focus on driver behavior norms and can be complemented by normative interventions in other settings to shape a key deterrent to cycling.
AssuntosCondução de Veículo , Humanos , Condução de Veículo/psicologia , Planetas , Austrália , Agressão , Inquéritos e Questionários , Ciclismo , Acidentes de Trânsito
AssuntosMeio Ambiente Extraterreno , Planetas , Evolução Planetária , Astronomia
Astrobiology is often defined as the study of the origin, evolution, distribution, and future of life on Earth and in the Universe. As a discipline that emerged in the past decades of the 20th century, its contours have not always been straightforward, resulting from the interweaving of several lines of research as early as the 1960s. By applying computational topic-modeling approaches to the complete full-text corpus of three flagship journals in the field, Origins of Life and Evolution of Biospheres (1968-2020), Astrobiology (2001-2020), and the International Journal of Astrobiology (2002-2020), we identify specific topics that characterize the early blossoming of the discipline. We also map their evolution through time, as emphasis changed between different readings of astrobiology, from an exobiology and origins-of-life perspective to a more space- and planetary-sciences view of the discipline.
AssuntosExobiologia , Origem da Vida , Planetas , Planeta Terra , Meio Ambiente Extraterreno
AssuntosMeio Ambiente Extraterreno , Gelo , Lua , Planetas , Meio Ambiente Extraterreno/química , Gelo/análise , Exobiologia
Antarctic deserts are among the driest and coldest ecosystems of the planet; there, some microbes survive under these extreme conditions inside porous rocks, forming the so-called endolithic communities. Yet the contribution of distinct rock traits to support complex microbial assemblies remains poorly determined. Here, we combined an extensive Antarctic rock survey with rock microbiome sequencing and ecological networks and found that contrasting combinations of microclimatic and rock traits such as thermal inertia, porosity, iron concentration, and quartz cement can help explain the multiple complex microbial assemblies found in Antarctic rocks. Our work highlights the pivotal role of rocky substrate heterogeneity in sustaining contrasting groups of microorganisms, which is essential to understand life at the edge on Earth and for the search for life on other rocky planets such as Mars.
AssuntosEcossistema , Exobiologia , Planetas , Planeta Terra , Regiões Antárticas
A balanced ratio of ocean to land is believed to be essential for an Earth-like biosphere, and one may conjecture that plate-tectonics planets should be similar in geological properties. After all, the volume of continental crust evolves toward an equilibrium between production and erosion. If the interior thermal states of Earth-sized exoplanets are similar to those of Earth-a straightforward assumption due to the temperature dependence of mantle viscosity-one might expect a similar equilibrium between continental production and erosion to establish, and hence a similar land fraction. We show that this conjecture is not likely to be true. Positive feedback associated with the coupled mantle water-continental crust cycle may rather lead to a manifold of three possible planets, depending on their early history: a land planet, an ocean planet, and a balanced Earth-like planet. In addition, thermal blanketing of the interior by the continents enhances the sensitivity of continental growth to its history and, eventually, to initial conditions. Much of the blanketing effect is, however, compensated by mantle depletion in radioactive elements. A model of the long-term carbonate-silicate cycle shows the land and the ocean planets to differ by about 5 K in average surface temperature. A larger continental surface fraction results both in higher weathering rates and enhanced outgassing, partly compensating each other. Still, the land planet is expected to have a substantially dryer, colder, and harsher climate possibly with extended cold deserts in comparison with the ocean planet and with the present-day Earth. Using a model of balancing water availability and nutrients from continental crust weathering, we find the bioproductivity and the biomass of both the land and ocean planets to be reduced by a third to half of those of Earth. The biosphere on these planets might not be substantial enough to produce a supply of free oxygen.
AssuntosMeio Ambiente Extraterreno , Planetas , Planeta Terra , Clima , Água
Health systems have a duty to protect the health and well-being of individuals and populations. Yet, healthcare contributes about 4.6% of global greenhouse gas emissions. Health systems need to question and improve established practices, assume strong environmental leadership, and aim for ambitious, sometimes radical, actions in favour of the climate. In this paper, we interrogate the suitability and feasibility of integrating the aim of 'environmental sustainability' to form the 'Sextuple Aim.' Environmental sustainability may be in tension with, but also a potential lever to meet the other cardinal aims: (1) quality and experience of patient care; (2) population health; (3) quality of work and satisfaction of healthcare providers; (4) equity and inclusion; and (5) cost reduction. We propose policy and practical avenues to help move towards the Sextuple Aim.