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A strikingly weird—even paradoxical—crystal

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Natalie Wolchover reports in Quanta:

In a deceptively drab black crystal, physicists have stumbled upon a baffling behavior, one that appears to blur the line between the properties of metals, in which electrons flow freely, and those of insulators, in which electrons are effectively stuck in place. The crystal exhibits hallmarks of both simultaneously.

“This is a big shock,” said Suchitra Sebastian, a condensed matter physicist at the University of Cambridge whose findings appeared today in an advance online edition of the journal Science. Insulators and metals are essentially opposites, she said. “But somehow, it’s a material that’s both. It’s contrary to everything that we know.”

The material, a much-studied compound called samarium hexaboride or SmB6, is an insulator at very low temperatures, meaning it resists the flow of electricity. Its resistance implies that electrons (the building blocks of electric currents) cannot move through the crystal more than an atom’s width in any direction. And yet, Sebastian and her collaborators observed electrons traversing orbits millions of atoms in diameter inside the crystal in response to a magnetic field — a mobility that is only expected in materials that conduct electricity. Calling to mind the famous wave-particle duality of quantum mechanics, the new evidence suggests SmB6 might be neither a textbook metal nor an insulator, Sebastian said, but “something more complicated that we don’t know how to imagine.”

“It is just a magnificent paradox,” said Jan Zaanen, a condensed matter theorist at Leiden University in the Netherlands. “On the basis of established wisdoms this cannot possibly happen, and henceforth completely new physics should be at work.”

It is too soon to tell what, if anything, this “new physics” will be good for, but physicists like Victor Galitski, of the University of Maryland, College Park, say it is well worth the effort to find out. “Oftentimes,” he said, “big discoveries are really puzzling things, like superconductivity.” That phenomenon, discovered in 1911, took nearly half a century to understand, and it now generates the world’s most powerful magnets, such as those that accelerate particles through the 17-mile tunnel of the Large Hadron Collider in Switzerland.

Theorists have already begun to venture guesses as to what might be going on inside SmB6. One promising approach models the material as a higher-dimensional black hole. But no theory yet captures the whole story. “I do not think that there is any remotely credible hypothesis proposed at this moment in time,” Zaanen said.

SmB6 has resisted classification since Soviet scientists first studied its properties in the early 1960s, followed by better-known experiments at Bell Labs.

Counting up the electrons in the orbital shells that surround its samarium and boron nuclei indicates that roughly half an electron should be left over, on average, per samarium nucleus (a fraction, because the nuclei have “mixed valence,” or alternating numbers of orbiting electrons). These “conduction electrons” should flow through the material like water flowing through a pipe, and thus, SmB6 should be a metal. “That’s the idea people had back when I started working on this problem as a young guy, around 1975,” said Jim Allen, an experimental physicist at the University of Michigan in Ann Arbor who has studied SmB6 on and off since then.

But while samarium hexaboride does conduct electricity at room temperature, things get strange as it cools.

Continue reading.

Written by LeisureGuy

2 July 2015 at 2:21 pm

Posted in Science

Pot’s Pesticide Problem

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Kaleigh Rogers reports at Motherboard on a problem due totally to marijuana being illegal instead of being legal, taxed, and regulated:

It goes without saying that growing weed is a little different from growing other kinds of crops. I mean, I don’t suspect vegetable farmers lose much sleep worrying aboutmischievous teens sneaking into their fields at night to grab fistfuls of organic kale (maybe hipster teens). But there’s one area where the difference between marijuana and other crops is particularly stark: pesticides, and it has both growers and consumers concerned.

For every other crop grown in the US, the chemicals used on them (like pesticides, herbicides, and fungicides) are carefully monitored and restricted by the Department of Agriculture and the Environmental Protection Agency. There are different limits setfor what kind of pesticides can be used and what is an acceptable level of chemicals that can be left behind on a crop (crops we eat, like tomatoes, are treated differently than crops we use for other purposes, like cotton).

But because marijuana is still illegal at the federal level, there are no protocols for pesticides when it comes to growing weed. From the federal government’s point of view, you shouldn’t be using any pesticides on cannabis because you shouldn’t be growing cannabis in the first place.

This has left growers with limited resources for trying to determine the best way to keep their crops healthy and their customers safe.

“Until very recently, it was the wild west: everyone was using whatever they wanted to, whatever they heard about on the internet,” said Whitney Cranshaw, a professor of entomology at the University of Colorado who studies pest management for crops. “Some were appropriate, others were inappropriate, but there was no direction from the feds, no direction from the state, no direction from anybody. So they just did what they thought was right.”

Recently, states where it’s legal to grow and sell medical or recreational marijuana have started rolling out recommendations for growers. In May, Colorado’s Department of Agriculture released a list of pesticides and fungicides that cannabis growers can use. Washington state followed suit earlier this month. But the lists are limited—they mostly focus on natural pesticides like cinnamon oil and garlic—and don’t provide a lot of info about the potential long-term effects of synthetic pesticides on a crop that isn’t just ingested, but inhaled.

“You can consume a large amount of pesticides from the plant by smoking it,” said Jeffrey Raber, a chemistry PhD who has studied the effects of pesticides on cannabis with his lab The WercShop. In 2013, The WercShop published a peer-reviewed study on the effects of pesticides on marijuana and found that up to 70 percent of pesticide residues on pot could be ingested through smoking. Aside from the high rate, Raber pointed out that inhaling a chemical very different from eating it.

“Usually the safety limits for a chemical on an inhalable substance are about ten times greater because they feel it’s that much more sensitive,” Raber said. “You don’t have stomach acid and your liver coming at things first. When you inhale things, it goes directly into your bloodstream. That’s a very different beast.”

The easy solution would seem to be looking to the pesticide restrictions on tobacco. People inhale tobacco the same way they inhale marijuana, so if a pesticide is safe to use on tobacco it must be safe for growing weed, right? Not quite, Raber said. Turns out the EPA has never been all that strict with tobacco regulations: research has shown the tobacco industry lobbies hard to keep its favored pesticides legal, and the list of pesticides commonly used on tobacco is fairly lengthy. Raber said at the end of the day, tobacco is getting mixed up with dozens of other nasty chemicals before it’s rolled into a cigarette. If you’re getting sick from a cigarette, it’s probably not because of a little bit of residual pesticide on the tobacco leaf.

And besides, Raber pointed out that tobacco, though also smoked, is a pretty different product than marijuana. While pot is often prescribed for people going through cancer treatments like chemotherapy to help ease pain and curb nausea, cigarettes are pretty much universally considered a bad idea when you’re going through chemo.

So if growers can’t look to the government and they can’t look to other crops as an example, what’s a modern day grow-op to do? . . .

Continue reading.

Written by LeisureGuy

30 June 2015 at 10:43 am

Posted in Business, Drug laws, Health

California Just Banned the ‘Personal Belief’ Exemption for Vaccines

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High time. When personal beliefs have a social cost that results in harm to the public, then it’s right that the government can act to protect the public. Kaleigh Rogers reports at Motherboard:

It’s official: California has passed a law prohibiting parents from using personal belief as an excuse to keep their kids unvaccinated.

Under the new law, parents can still choose not to vaccinate their children if they wish, but those kids won’t be allowed to attend public schools or daycares, and will have to either be homeschooled or enter a private school.

There are a few exceptions: kids who can’t be vaccinated for medical reasons are exempt from the ruling, and only 10 specific vaccines are required, including the vaccine for measles, mumps, and rubella. Children who have special education needs will also still be guaranteed access to resources they need if they are booted from public school for being unvaccinated.

Last week, California’s State Assembly considered the bill, which had already been green-lit by the state senate, ultimately voting to approve it 46-30. This week, the senate approved the amendments that were added to the bill before passing it to the desk of Democratic Governor Jerry Brown, who signed the bill this morning.

“The science is clear that vaccines dramatically protect children against a number of infectious and dangerous diseases,” the governor wrote in a memo about his decision. “While it’s true that no medical intervention is without risk, the evidence shows that immunization powerfully benefits and protects the community.” . . .

Continue reading.

Written by LeisureGuy

30 June 2015 at 10:39 am

Addiction: Not a disease, but an example of the brain’s plasticity in learning

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Very interesting article in Salon by Laura Miller. The whole thing’s worth reading, but note this:

. . .  This conception of addiction as a biological phenomenon seemed to be endorsed over the past 20 years as new technologies have allowed neuroscientists to measure the human brain and its activities in ever more telling detail. Sure enough, the brains of addicts are physically different — sometimes strikingly so — from the brains of average people. But neuroscience giveth and now neuroscience taketh away. The recovery movement and rehab industry (two separate things, although the latter often employs the techniques of the former) have always had their critics, but lately some of the most vocal have been the neuroscientists whose findings once lent them credibility.

One of those neuroscientists is Marc Lewis, a psychologist and former addict himself, also the author of a new book “The Biology of Desire: Why Addiction is Not a Disease.” Lewis’s argument is actually fairly simple: The disease theory, and the science sometimes used to support it, fail to take into account the plasticity of the human brain. Of course, “the brain changes with addiction,” he writes. “But the way it changes has to do with learning and development — not disease.” All significant and repeated experiences change the brain; adaptability and habit are the brain’s secret weapons. The changes wrought by addiction are not, however, permanent, and while they are dangerous, they’re not abnormal. Through a combination of a difficult emotional history, bad luck and the ordinary operations of the brain itself, an addict is someone whose brain has been transformed, but also someone who can be pushed further along the road toward healthy development. (Lewis doesn’t like the term “recovery” because it implies a return to the addict’s state before the addiction took hold.)

“The Biology of Desire” is grouped around several case studies, each one illustrating a unique path to dependency. A striving Australian entrepreneur becomes caught up in the “clarity, power and potential” he feels after smoking meth, along with his ability to work long hours while on the drug. A social worker who behaves selflessly in her job and marriage constructs a defiant, selfish, secret life around stealing and swallowing prescription opiates. A shy Irishman who started drinking as a way to relax in social situations slowly comes to see social situations as an occasion to drink and then drinking as a reason to hole up in his apartment for days on end.

Each of these people, Lewis argues, had a particular “emotional wound” the substance helped them handle, but once they started using it, the habit itself eventually became self-perpetuating and in most cases ultimately served to deepen the wound. Each case study focuses on a different part of the brain involved in addiction and illustrates how the function of each part — desire, emotion, impulse, automatic behavior — becomes shackled to a single goal: consuming the addictive substance. The brain is built to learn and change, Lewis points out, but it’s also built to form pathways for repetitive behavior, everything from brushing your teeth to stomping on the brake pedal, so that you don’t have to think about everything you do consciously. The brain is self-organizing. Those are all good properties, but addiction shanghais them for a bad cause.

As Lewis sees it, addiction really is habit; we just don’t appreciate how deeply habit can be engraved on the brain itself. “Repeated (motivating) experience” — i.e., the sensation of having one’s worries wafted away by the bliss of heroin — “produce brain changes that define future experiences… So getting drunk a lot will sculpt the synapses that determine future drinking patterns.” More and more experiences and activities get looped into the addiction experience and trigger cravings and expectations like the bells that made Pavlov’s dogs salivate, from the walk home past a favorite bar to the rituals of shooting up. The world becomes a host of signs all pointing you in the same direction and activating powerful unconscious urges to follow them. At a certain point, the addictive behavior becomes compulsive, seemingly as irresistibly automatic as a reflex. You may not even want the drug anymore, but you’ve forgotten how to do anything else besides seek it out and take it. . .

Read the whole thing.

Written by LeisureGuy

28 June 2015 at 12:24 pm

Foods that work together

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An interesting article from Eliza Barclay at NPR. Note that an oil-based dressing does as well as an egg in a green salad, but certainly a poached egg atop a salad—or, less ambitiously, a boiled egg or two sliced into the salad—is more interesting.

I like that she explains the why—e.g., red bell pepper with beans because the vitamin C the pepper adds helps. That lets one decide to use, say, orange sections instead in a bean salad.

What are the makings of a great salad? You need fresh greens, of course, and then a layer of colorful vegetables like tomatoes and carrots.

That’s a good start. But to help the body absorb more of the nutrients packed into this medley, you may want to add something else: a cooked egg.

A small study published in May in The American Journal of Clinical Nutritionconcludes that adding eggs to salads makes it easier to absorb the carotenoids in the raw vegetables. Carotenoids are the yellowish-red pigments that give carrots and tomatoes — and lots of other fruits and vegetables — their color. Two famous ones are beta carotene and lycopene. In addition to giving us those pretty colors, they’re also beneficial phytonutrients that help fight inflammation.

For the study, the researchers gave 16 participants raw mixed-vegetable salad with no eggs, a salad with one and a half eggs and a salad with three eggs. They found that the absorption of carotenoids was 3.8-fold higher when the salad included three eggs compared to no eggs.

Now, we should point out that the study was funded by a grant from the American Egg Board’s Egg Nutrition Center, which may raise eyebrows. But the scientists at Purdue University who carried out the study say they worked independently. And the findings hold up, since the scientific mechanism behind this phenomenon is well-documented in other studies.

It’s the fat in the egg yolk that is responsible for upping the nutrient intake. And, as we’ve reported, oil-based salad dressing helps accomplish the same goal.

The dynamic duo of eggs and carrots (or any other vegetable or fruit high in carotenoids) got us wondering about other food power couples. Turns out, they’re not so hard to find.

“The impact of consuming one food with another on the absorption of nutrients is well known in nutrition science,” Wayne Campbell, professor of nutrition science at Purdue University and lead author of the egg and salad study, tells The Salt. “Sometimes the impact may be positive and at other times negative.”

A classic example: After corn is soaked in lime and water, then ground up, all kinds of nutrients in the corn are released and made available for absorption — calcium, iron, niacin and minerals. This is why corn tortillas have been one of the bedrocks of Mesoamerican cuisine for millennia.

So, what about some other foods that you might as well throw together if you’ve got them on hand?

Campbell tells us that eating something high in vitamin C, like a red pepper, helps convert the nonheme iron in plant foods and iron-fortified foods into a chemical form that promotes absorption. (The other form of iron is heme iron, which is only found in meat and seafood.) Sounds like a good excuse to go Tex-Mex and stir some peppers into your black beans. . .

Continue reading. The article discusses other good combinations.

I am right now altering the Breakfast Bites recipe to include lots of freshly ground black pepper to aid with the turmeric.

Written by LeisureGuy

26 June 2015 at 8:51 am

Posted in Daily life, Food, Health, Science

California’s Drought Is Part of a Much Bigger Water Crisis. Here’s What You Need to Know

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Abrahm Lutgarten, Lauren Kirchner, and Amanda Zamora report at ProPublica:

Why do I keep hearing about the California drought, if it’s the Colorado River that we’re “killing”?

Pretty much every state west of the Rockies has been facing a water shortage of one kind or another in recent years.  California’s is a severe, but relatively short-term, drought. But the Colorado River basin — which provides critical water supplies for seven states including California — is the victim of a slower-burning catastrophe entering its 16th year. Wyoming, Colorado, New Mexico, Utah, Nevada, Arizona and California all share water from the Colorado River, a hugely important water resource that sustains 40 million people in those states, supports 15 percent of the nation’s food supply, and fills two of largest water reserves in the country.

The severe shortages of rain and snowfall have hurt California’s $46 billion agricultural industry and helped raise national awareness of the longer-term shortages that are affecting the entire Colorado River basin. But while the two problems have commonalities and have some effect on one another, they’re not exactly the same thing.

Just how bad is the drought in California right now?

Most of California is experiencing “extreme to exceptional drought,” and the crisis has now entered its fourth year. This month, signaling how serious the current situation is, state officials announced the first cutback to farmers’ water rights since 1977, andordered cities and towns to cut water use by as much as 36 percent. Those who don’t comply with the cuts will face fines, but some farmers are already ignoring the new rules, or challenging them in court.

The drought shows no sign of letting up any time soon, and the state’s agricultural industry is suffering. A recent study by U.C. Davis researchers projected that the drought would cost California’s economy $2.7 billion in 2015 alone.

In addition to the economic cost, the drought has subtle and not-so-subtle effects on flora and fauna throughout the region. This current drought may be contributing to the spread of the West Nile virus, and it’s threatening populations of geese, ducks and Joshua trees. Dry, hot periods can exacerbate wildfires, while water shortages are making firefighters’ jobs even harder.

And a little bit of rain won’t help. NOAA scientists say it could take several years of average or above-average rainfall before California’s water supply can return to anything close to normal.

What about a lot of rain? Couldn’t that end the drought in California and across the West?

Not necessarily. A half-decade of torrential rains might bail California out of its crisis, but the larger West’s problems are more structural and systemic.  “Killing the Colorado” has shown that people are entitled to more water from the Colorado than has flowed through it, on average, over the last 110 years. Meanwhile much of the water is lost, overused or wasted, stressing both the Colorado system, and trickling down to California, which depends on the Colorado for a big chunk of its own supply. Explosive urban growthmatched with the steady planting of water-thirsty crops – which use the majority of the water – don’t help. Arcane laws actually encourage farmers to take even more water from the Colorado River and from California’s rivers than they actually need, and federal subsidies encourage farmers to plant some of the crops that use the most water. And, as ProPublica has reported, it seems that “the engineering that made settling the West possible may have reached the bounds of its potential” — meaning that even the big dams and canals we built to ferry all this water may now be causing more harm than good.

Water use policies—perhaps more than nature—have caused the water crisis in the West. As the former Arizona governor and U.S. Secretary of the Interior Bruce Babbitt told ProPublica: “There is enough water in the West‚ [but] there are all kinds of agriculture efficiencies that have not been put into place.”

While there are mixed views on whether climate change can be blamed for California’s drought, a recent National Oceanic and Atmospheric Administration (NOAA) reportfound climate change was not the cause. Global warming has caused excessive heat that may have worsened the drought’s effects, but it isn’t necessarily to blame for the lack of rain. It’s true that recent years have yielded much less rain and snow than previous times in history, the NOAA report explains, but that’s just a result of “natural variance” and not necessarily because of man-made pollution. But in both California and the larger Colorado River basin, mismanagement of the water supply has left the West more vulnerable to both short and long-term changes in climate.

What do you mean by mismanagement?

When officials divvied up rights to Colorado River water nearly a century ago, it happened to be a wetter period than usual. The result? The states vastly overestimated the river’s annual flow. Today, the river’s reserves are especially low and states are stillclaiming the same amount of water from the Colorado River that they always have — which is 1.4 trillion gallons a year more than the river actually produces. This sort of oversubscription is similar in California, where historic water rights give many farms first rights to California’s streams and rivers, and haven’t been adjusted as the state’s population has increased and its cities have grown.

Wait — don’t we all have equal water rights? . . .

Continue reading.

Written by LeisureGuy

25 June 2015 at 2:40 pm

Worst foods for pesticide residue—and foods with the least pesticide residue

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From EWG, the foods with the worst pesticide residue—so buy these foods from the organic section:

  1. Apples
  2. Peaches
  3. Nectarines
  4. Strawberries
  5. Grapes
  6. Celery
  7. Spinach
  8. Sweet bell peppers
  9. Cucumbers
  10. Cherry tomatoes
  11. Snap peas – imported
  12. Potatoes
  13. Hot Peppers
  14. Kale / Collard greens

And the foods lowest in pesticide residue, so safe to buy from the conventional section:

  1. Asparagus
  2. Avocado
  3. Cabbage
  4. Cantaloupe
  5. Carrots
  6. Cauliflower
  7. Eggplant
  8. Grapefruit
  9. Kiwi
  10. Onion
  11. Mango
  12. Mushroom
  13. Papaya
  14. Pineapple
  15. Sweet corn
  16. Sweet peas
  17. Sweet potatoes (I prefer Jewell)
  18. Watermelon

Broccoli is another safe one. Check the link.

Nice touch: they offer a mobile phone app so you can get food’s score as you shop.

Written by LeisureGuy

24 June 2015 at 3:40 pm

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