Lunar Dust Is Deadly

first_imgA significant fraction of lunar dust could pose deadly risks to future astronauts stationed on the moon, a BBC News report says.  About 1-3% of moon dust particles are too small to be coughed up or removed by the cilia lining the respiratory tract.  These would lodge in the lungs and become inflamed.  As in silicosis and asbestosis, the lung responds by building scar tissue around the particles, but this reduces the effective surface of the lungs for oxygen intake.    The article has a microphoto of a dust grain that is filled with cavities, like swiss cheese.  These would have up to five times the surface area to interfere with the lungs.  Having jagged surfaces, they would be less likely to be captured by the sinus walls because of the way the particles would follow the path of the air.    Another problem is with iron grains in 10-20 nanometer particles of lunar dust.  These “nano-phase iron” particles could be absorbed directly into the bloodstream and interfere with hemoglobin’s ability to absorb oxygen.  The fine dust was irritating to Apollo astronauts during their brief visits.  It got into everything and clung like powder.  The lunar rovers kicked up roostertails of dust.  Harrison Schmidt got a bout of “lunar dust hay fever” after returning to the lunar module.    NASA would like to set up camp on the moon once again in the year 2020.  A Lunar Airborne Dust Toxicity Advisory Group has been working on the problems.  The article discusses techniques the team of medical doctors and scientists are developing to mitigate the hazards of lunar dust.  The iron can be extracted with magnets, for instance, and dust can be melted with microwaves into a kind of paved glass.  Robots may have to employ microwave guns, magnets, vacuums and filters to pave the way for human habitation.  Large amounts of lunar soil will need to be collected for a moon base for building materials, oxygen and hydrogen.  These actions might cause some fine dust to levitate above the surface, however, posing threats to scientific instruments and astronaut health.  Extracting and living on the moon’s “toxic” dust will be a major challenge for the next generation of human rovers.There’s dust on Earth, too, but….  In most cases (except in man-made habitats like mines and in smoke-filled rooms), our bodies are tuned to the geology and geography and atmosphere.  The atmosphere transports large amounts of dust, but clouds and rain cleanse it and allow dust to solidify into rocks or be transported to the oceans.  Meanwhile, our sinuses, mucous membranes and sneeze responses trap and expel much of the dust that enters our airways, allowing most of us to enjoy many decades of healthy breathing.  Pushing the human body outside the envelope is teaching us many things we might otherwise take for granted.  It’s revealing an amazing degree of tuning of the body to its habitat.    The moon is the same distance from the sun as Earth, but look how different it is.  Nice place to visit, but you wouldn’t want to live there for long.  The lack of sufficient mass to retain an atmosphere and allow liquid water makes all the difference in the world.(Visited 16 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img read more


Brain Makes Automatic Statistical Inference

first_imgYour brain isn’t a computer, but contains a powerful one.Scientists at the University of Cambridge say, “the brain is a really smart statistical machine: it looks for patterns and finds building blocks to construct objects.” For example, you can look at clothing on a mannequin inside a store and infer what the fabric feels like, just by judging its texture and color.Our ability to extract distinct objects from cluttered scenes by touch or sight alone and accurately predict how they will feel based on how they look, or how they look based on how they feel, is critical to how we interact with the world.By performing clever statistical analyses of previous experiences, the brain can immediately both identify objects without the need for clear-cut boundaries or other specialised cues, and predict unknown properties of new objects. The results are reported in the open-access journal eLife.To accomplish this kind of inference, the brain breaks up the stream of information coming at it from the senses into chunks, the press release explains, a bit like pieces of a jigsaw puzzle. Experiments with puzzles showed that subjects correctly inferred the unknown properties from the chunks of known properties.“These results challenge classical views on how we extract and learn about objects in our environment,” said Lengyel. “Instead, we’ve show that general-purpose statistical computations known to operate in even the youngest infants are sufficiently powerful for achieving such cognitive feats.“The paper in eLife did not use any reference to evolution, nor did the press release. Instead, it referred to something non-physical: the abstract reality of concepts.The concept of objects is fundamental to cognition and is defined by a consistent set of sensory properties and physical affordances [properties that the environment offers the individual]. Although it is unknown how the abstract concept of an object emerges, most accounts assume that visual or haptic boundaries are crucial in this process. Here, we tested an alternative hypothesis that boundaries are not essential but simply reflect a more fundamental principle: consistent visual or haptic [touch-related] statistical properties.The coherent organization of information across different modalities is crucial for efficiently interacting with the world and lies at the heart of the concept of what defines an object.[S]tatistical learning goes beyond the learning of simple (pairwise) associations between the constituent components of objects, and has been shown to be best described as the extraction of statistically meaningful (potentially multivariate) latent ‘chunks’). Therefore, we propose that these latent chunks are the abstract representations that are built automatically during exposure and mediate the across-modality effects we observed.Together, these results suggest that statistical learning is not only a domain-general mechanism but it also results in domain-general internal representations that could be the basis for the emergence of affordances and the abstraction of object concepts.The brain, therefore, is adept at combining information and concepts. This sounds more like a top-down process of computational abilities, not a bottom-up pairwise association of sensory perceptions, as John Locke proposed for the emergence of ideas. Any bottom-up mechanical philosophy, in fact, has to presuppose the very abilities of thought that it tries to explain. That includes Darwinism.One doesn’t have to use the silly “inner pickpocket” analogy contrived by the lead author, who said “These results suggest there is a secret, statistically savvy pickpocket in all of us.” Pickpockets might access the ability to infer properties by touch, but they simply use for evil purposes a complex ability with which all of us come endowed by our Creator. The authors did not refer to evolution at all. How could they? A blind, aimless process like natural selection is oblivious to the world of logical inference, statistical inference, and concepts. Those require thought, even if they utilize the tools of neurons. Thought falsifies atheism. C.S. Lewis said,Supposing there was no intelligence behind the universe, no creative mind. In that case, nobody designed my brain for the purpose of thinking. It is merely that when the atoms inside my skull happen, for physical or chemical reasons, to arrange themselves in a certain way, this gives me, as a by-product, the sensation I call thought. But, if so, how can I trust my own thinking to be true? It’s like upsetting a milk jug and hoping that the way it splashes itself will give you a map of London. But if I can’t trust my own thinking, of course I can’t trust the arguments leading to Atheism, and therefore have no reason to be an Atheist, or anything else. Unless I believe in God, I cannot believe in thought: so I can never use thought to disbelieve in God.(Visited 380 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img read more