Tag Archives: Science

Why Does the Moon Appear Larger on the Horizon?

Why does the Moon look so huge on the horizon?

If you’ve ever seen the Moon rising over the horizon, looking so fat and looming that you felt like you could fall right into it, then you’ve been a victim of the famous Moon Illusion. And it is an illusion, a pervasive and persuasive one.
…
When the Moon is on the horizon, your brain thinks it’s far away, much farther than when it’s overhead. So the Ponzo Illusion kicks in: your brain sees the Moon as being huge, and it looks like you could fall into it. The Illusion works for the Sun, too. In fact, years ago I saw Orion rising over a parking lot, and it looked like it was spread across half the sky. It’s an incredibly powerful illusion.

Oddly enough, when it’s on the horizon, the Moon actually is farther away than when it’s overhead. Not by much, really, just a few thousand kilometers (compared to the Moon’s overall distance of about 400,000 kilometers).
…
So the Moon Illusion is just that. It’s not the air acting like a lens, or foreground objects making it look big by comparison. It’s just the way we see the shape of the sky together with the well-known Ponzo Illusion.
..
Science taking something we perceive as real, breaking it down, and showing it to be an interesting but decidedly unreal illusion? Well, that’s what science does! It helps us not only understand the world better, but it also makes the world cooler, too.

Ironmaking at the National Museum of Science and Technology in Stockholm

Joakim Storck discusses pre–industrial Swedish and Japanese techniques for iron and sword making from a museum demonstration at Tekniska museet. Ironmaking at the National museum of science and technology, Stockholm 2005

Bricklaying is a messy story. The mortar consists of clay, sand and horse manure (if available), mixed with water to a fairly loose batter. The best finish is obtained if you work with your hands as the mortar is placed on, and smears with water so that the surface becomes smooth and fine. When then furnace is ready, it is dried through slow heating by wood without blasting, until the moist has been driven out of the mud. At this stage, heating should be quite cautious in order to avoid cracking.

Then, on Friday September 9, we went again with a fully loaded trailer from Dalarna in the direction of Stockholm. More than a few people were probably turning their heads when we passed, because the trailer was dominated by a large bellow — our newly built two chamber bellow with an estimated bladder capacity of up to 800 litres per minute. In addition, we brought fire wood, iron rods, pliers, some stumps and other stuff needed for the furnace operation.
…
We made one run each on Saturday and Sunday. Each time we charged a total of about 10kg ore added in amounts of about 1kg every 20 minute. For each charge, we added about twice the amount of charcoal. Discharging of the loupe was scheduled for two o’clock, and by that time a fairly large crowd had gathered to see the show. This time we managed to get the loupe out of the furnace without too much trouble. Worse was that the process took longer than expected, but the crowd seemed to be patient and people stayed around until the end.

Trying to Find Pest Solutions While Hoping Evolution Doesn’t Exist Doesn’t Work

How To Make A Superweed

Melander wondered why some populations of scales were becoming able to resist pesticides. Could the sulfur-lime spray trigger a change in their biology, the way manual labor triggers the growth of callouses on our hands? Melander doubted it. After all, ten generations of scales lived and died between sprayings. The resistance must be hereditary, he reasoned. He sometimes would find families of scales still alive amidst a crowd of dead insects.

This was a radical idea at the time. Biologists had only recently rediscovered Mendel’s laws of heredity. They talked about genes being passed down from one generation to the next, yet they didn’t know what genes were made of yet. But they did recognize that genes could spontaneously change–mutate–and in so doing alter traits permanently.
…
In the short term, Melander suggested that farmers switch to fuel oil to fight scales, but he warned that they would eventually become resistant to fuel oil as well. In fact, the best way to keep the scales from becoming entirely resistant to pesticides was, paradoxically, to do a bad job of applying those herbicides. By allowing some susceptible scales to survive, farmers would keep their susceptible genes in the scale population. “Thus we may make the strange assertion that the more faulty the spraying this year the easier it will be to control the scale the next year,” Melander predicted.
…
What’s striking is how many different ways weeds have found to overcome the chemical. Scientists had thought that Roundup was invincible in part because the enzyme it attacks is pretty much the same in all plants. That uniformity suggests that plants can’t tolerate mutations to it; mutations must change its shape so that it doesn’t work and the plant dies. But it turns out that many populations of ryegrass and goosegrass have independently stumbled across one mutation that can change a single amino acid in the enzyme. The plant can still survive with this altered enzyme. And Roundup has a hard time attacking it thanks to its different shape.
…
Another way weeds fight off Roundup is through sheer numbers. Earlier this year an international team of scientists reported their discovery of how Palmer amaranth resists glyphosate. The plants make the ordinary, vulnerable form of the enzyme. But the scientists discovered that they have many extra copies of the gene for the enzyme–up to 160 extra copies, in fact.
…
What makes the evolution of Roundup resistance all the more dangerous is how it doesn’t respect species barriers. Scientists have found evidence that once one species evolves resistance, it can pass on those resistance genes to other species. They just interbreed, producing hybrids that can then breed with the vulnerable parent species.

Another great article from Carl Zimmer.

Food Rules: An Eater’s Manual

Good advice from author Michael Pollan on eating from his new book, Food Rules: An Eater’s Manual. Essentially he suggests eating food. Stuff you can picture in the original form (apples, cashews, celery, trout, tomatoes, grapes, steak, strawberries, milk, figs, peppers, peaches, almonds, chicken) not chemical additions (yes I know real food is made up of chemical – this is additional chemicals). One quote: “the biggest gains in human health can be made from changes in food policy.”

Human health is a complex topic but if we care about our health it is a tough issue we have to try to understand. He makes a good point in his talk about the value of exercise. I do believe exercise is an important component to how to be healthy (as is food – I don’t think it is easy to be healthy without both).

Bee Colonies Continue to Collapse

The activity to find the causes of Colony Collapse Disorder provides a view into the scientific inquiry process of complex living systems. Finding answers is not easy.

Fears for crops as shock figures from America show scale of bee catastrophe

Disturbing evidence that honeybees are in terminal decline has emerged from the United States where, for the fourth year in a row, more than a third of colonies have failed to survive the winter.

The decline of the country’s estimated 2.4 million beehives began in 2006, when a phenomenon dubbed colony collapse disorder (CCD) led to the disappearance of hundreds of thousands of colonies. Since then more than three million colonies in the US and billions of honeybees worldwide have died and scientists are no nearer to knowing what is causing the catastrophic fall in numbers.
…
It is estimated that a third of everything we eat depends upon honeybee pollination.
…
Potential causes range from parasites, such as the bloodsucking varroa mite, to viral and bacterial infections, pesticides and poor nutrition stemming from intensive farming methods.
…
“We believe that some subtle interactions between nutrition, pesticide exposure and other stressors are converging to kill colonies,” said Jeffery Pettis, of the ARS’s bee research laboratory.
…
“It’s getting worse,” he said. “The AIA survey doesn’t give you the full picture because it is only measuring losses through the winter. In the summer the bees are exposed to lots of pesticides. Farmers mix them together and no one has any idea what the effects might be.” Pettis agreed that losses in some commercial operations are running at 50% or greater.

High Levels of Miticides and Agrochemicals in North American Apiaries: Implications for Honey Bee Health (open access paper on the topic, March 2010)

The 98 pesticides and metabolites detected in mixtures up to 214 ppm in bee pollen alone represents a remarkably high level for toxicants in the brood and adult food of this primary pollinator. This represents over half of the maximum individual pesticide incidences ever reported for apiaries. While exposure to many of these neurotoxicants elicits acute and sublethal reductions in honey bee fitness, the effects of these materials in combinations and their direct association with CCD or declining bee health remains to be determined.

Antibiotics, Farming and Superbugs

Antibiotics and farming – how superbugs happen

Provocative new research from Boston University’s medical school and department of biomedical engineering now suggests, though, that multi-drug resistance can be acquired in one pass, through a different mutational process triggered by sublethal doses of antibiotics – the same sort of doses that are given to animals on farms.

In earlier work, the authors found that antibiotics attack bacteria not only in the ways they are designed to (the beta-lactams such as methicillin, for instance, interfere with staph’s ability to make new cell walls as the bug reproduces, causing the daughter cells to burst and die), but also in an unexpected way. They stimulate the production of free radicals, oxygen molecules with an extra electron, that bind to and damage the bacteria’s DNA.

That research used lethal doses of antibiotics, and ascertained that the free-radical production killed the bacteria. In the new research, the team uses sublethal doses, and here’s what they find: The same free-radical production doesn’t kill the bacteria, but it acts as a dramatic stimulus to mutation, triggering production of a wide variety of mutations

Webcast on Finding the Missing Memristor

Very interesting lecture on finding the missing memristor by R. Stanley Williams. From our post in 2008:

How We Found the Missing Memristor By R. Stanley Williams:

For nearly 150 years, the known fundamental passive circuit elements were limited to the capacitor (discovered in 1745), the resistor (1827), and the inductor (1831). Then, in a brilliant but underappreciated 1971 paper, Leon Chua, a professor of electrical engineering at the University of California, Berkeley, predicted the existence of a fourth fundamental device, which he called a memristor.

Evidence that Refined Carbohydrates Threaten the Heart

More Evidence that Refined Carbohydrates, not Fats, Threaten the Heart

Eat less saturated fat: that has been the take-home message from the U.S. government for the past 30 years. But while Americans have dutifully reduced the percentage of daily calories from saturated fat since 1970, the obesity rate during that time has more than doubled, diabetes has tripled, and heart disease is still the country’s biggest killer. Now a spate of new research, including a meta-analysis of nearly two dozen studies, suggests a reason why: investigators may have picked the wrong culprit. Processed carbohydrates, which many Americans eat today in place of fat, may increase the risk of obesity, diabetes and heart disease more than fat does – a finding that has serious implications for new dietary guidelines expected this year.
…
Right now, Post explains, the agency’s main message to Americans is to limit overall calorie intake, irrespective of the source. “We’re finding that messages to consumers need to be short and simple and to the point,” he says. Another issue facing regulatory agencies, notes Harvard’s Stampfer, is that “the sugared beverage industry is lobbying very hard and trying to cast doubt on all these studies.”

The medical studies about what food to eat to remain healthy can be confusing but some details are not really in doubt. So while the exact dangers of processed carbohydrates, fat, excess calories and high fructose corn syrup may be in question their is no doubt we, in the USA, are not as healthy as we should be. And food is a significant part of the problem. Eat food, not too much, mostly plants and get enough exercise is good advice.

Non-infectious Prion Protein Linked to Alzheimer’s Disease

‘Harmless’ prion protein linked to Alzheimer’s disease

Non-infectious prion proteins found in the brain may contribute to Alzheimer’s disease, researchers have found.
…
normal prion proteins produced naturally in the brain interact with the amyloid-Î² peptides that are hallmarks of Alzheimer’s disease. Blocking this interaction in preparations made from mouse brains halted some neurological defects caused by the accumulation of amyloid-Î² peptide. It was previously thought that only infectious prion proteins, rather than their normal, non-infectious counterparts, played a role in brain degeneration.
…
Alzheimer’s disease has long been linked to the build-up of amyloid-Î² peptides, first into relatively short chains known as oligomers, and then eventually into the long, sticky fibrils that form plaques in the brain. The oligomeric form of the peptide is thought to be toxic, but exactly how it acts in the brain is unknown.

South African Fossils Could be New Hominid Species

South African fossils could be new hominid species

The fossils of a female adult and a juvenile male – perhaps mother and son – are just under two million years old. They were uncovered in cave deposits at Malapa not far from Johannesburg.

Researchers tell the journal Science that the creatures fill an important gap between older hominids and the group of more modern species known as Homo, which includes our own kind. The team has assigned the name Australopithecus sediba to their finds.

“It’s at the point where we transition from an ape that walks on two legs to, effectively, us,” lead scientist Professor Lee Berger of the University of the Witwatersrand told BBC News.

“I think that probably everyone is aware that this period of time – that period between 1.8 and just over two million years [ago] – is one of the most poorly represented in the entire early hominid fossil record. You’re talking about a very small, very fragmentary record,” he explained.
…
Their bones were laid down with the remains of other dead animals, including a sabre-toothed cat, antelope, mice and rabbits. The fact that none of the bodies appear to have been scavenged indicates that all died suddenly and were entombed rapidly.

“We think that there must have been some sort of calamity taking place at the time that caused all of these fossils to come down together into the cave where they got trapped and ultimately buried,” said team-member Professor Paul Dirks from James Cook University in Queensland, Australia.

All were preserved in the hard calcified clastic sediment that formed at the bottom of a pool of water.