What are the effects of yoga and meditation on the brain?

Question: What are the effects of yoga and meditation on the brain?

Answer: Yoga and meditation have effects on physiology, brain chemistry, and cognitive processes; these vary depending on the exact type of practise being performed and how long a person has practised it for. Studies of brain activity confirm that meditation can achieve a state of calm, thoughtless awareness, by suppressing brain regions involved in external attention and irrelevant information, and activating brain regions involved in internalised attention and positive emotions. Meditation is thought to activate the parasympathetic-limbic pathways, reducing heart rate, lowering blood pressure and slowing breathing. Meditation practises can fundamentally change the shape, structure and function of the brain – reinforcing neural networks, developing particular brain regions and influencing the production of key neurotransmitters and hormones in the brain related to attention, self-awareness and emotional control. Yoga has far-reaching effects on the body, reducing inflammation, boosting mood and making long-term practitioners feel more awake. It may even speed up learning in childhood and slow the natural cognitive declines that come with ageing. However, our understanding of the effects of meditative practises on the brain and body is still in its infancy – much more work remains (especially large-scale, carefully controlled trials).

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Can bees only sting me once?

Question: Can bees only sting me once?

Answer: Honeybees are generally killed by stinging you, but most other stinging insects can survive to sting you again.

It’s a common urban myth that bees can only sting once, but it’s partially based in truth. Honeybees have a barbed stinger, and if they sting a thick-skinned mammal like a human, the barbed hook gets stuck as they try to pull away, ripping their insides out and killing the bee within a few minutes. But if they were to sting another insect, or a vertebrate with thinner skin, they’d probably live to tell the tale.

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How much land on Earth is inhabited?

Question: How much of the land on Earth is covered by humans?

Answer: Approximately 10%.

This question is an interesting one because, when my friend asked me the other day, I could tell her confidently that not only did science know the answer, science had multiple different ways to quantify that answer, but that I had absolutely no idea what it was.

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What is a Nut?

Question: What is a Nut?

Answer: In Botanical terms, a nut is a hard-shelled fruit, which does not open to release its seed. There are relatively few true nuts because dehiscent fruit (where the shell does split open) is far more common; true nuts include chestnuts, pecans and hazelnuts. Not all nuts are closely related to each other on the family tree of plants though – indehiscence has evolved multiple times as a strategy for seed dispersal.

However, the word nut is used to refer to a huge range of hard fruits and seeds, from legumes (e.g. peanuts) to drupes (e.g. coconuts and cashews).

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Why Does Sour Food Make us Cringe?

Question: Why Does Sour Food Make Us Cringe?

Answer: Turns out, not many people have directly looked at this – the scientific literature has relatively little to say on the topic of cringing at sour food. However, what it does say is this: the cringing facial expressions are part of a general ‘disgust’ response that we make towards unpleasant smells and tastes. Some aspects of the face we pull when we eat sour sweets or a particularly tart tangerine are also produced when we smell off milk or bite into a rotten apple. The disgust response is designed to stop us from eating poisonous or rotten food, and to communicate with others around us that the food is bad. It probably formed a key part of social foraging, enabling early humans to avoid bad food and share information within their social group.

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How Much Would a Mole of Moles Weigh?

Question: How much would a mole of moles weigh?

Answer: There are two ways to interpret this question, both of which are equally silly. Maybe you mean a mole (unit of measurement) of moles (the subterranean mammal), or perhaps you mean, how much would a mole of mole molecules weigh? I’ll deal with each possibility in turn.

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Which is slimier?

Q: Is a Slug Slimier than a Snail?

A: Land snails and slugs like the ones you get in your garden are members of the class Gastropoda, along with sea snails, sea slugs and limpets. However, they do not represent distinct branches of the evolutionary tree – slugs are just species of snail that have lost their shell. There are even some snails that have a reduced shell – halfway between slug and snail. So this makes it difficult to answer the question.

However, there are some good reasons why slugs (shell-less snails) might seem to be slimier than their shelled counterparts.

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Can Chickens Change Sex?

Not the most pervasive of suburban legends, granted, but it seems to keep popping up. It goes something like this…

Confused Farmer finds Hen is now Cock
The mature hen, Gertie, who had laid eggs the previous year, suddenly stopped, grew chin wattles and started to crow.

So, can chickens really change sex? – Short answer: NO

The Long Answer

There are a few different explanations for stories such as these, but the important point of all of them is that these apparent sex changes are merely superficial – the hen might be visually and behaviourally male, but she is still unable to fertilise another hen’s eggs. So why does the hen suddenly start crowing? Continue reading