As most people know, muscles can only pull and relax, they can't push. When called upon, the cells in a muscle contract, which shortens the muscle and makes a body part move. So when you bend your arm, your biceps contract and shorten, pulling the underarm at the elbow and bending it. At the same time, the triceps relaxes. By next contracting this muscle, the arm stretches again.
Muscles can only pull, they can't push.
But think about this.

Recently the news hit the headlines that Neanderthals had some DNA of Homo sapiens in their genome. Before that, the reverse had already been demonstrated, namely that modern people can have Neanderthal genes. And because not all individuals have the same Neanderthal genes, if you add all those genes up, the complete human population has a considerable amount of genes that once made a Neanderthal tick.

Being a scientist myself, I deeply respect scientific arguments to support a theory. But sometimes, scientific knowledge gets in the way of progress.
Take Lord Kelvin, who, being a physicist, estimated the age of our planet Earth based on the rate of its past cooling. This only supported an age of 100 million years. His calculations were based on accurate physical knowledge as was available at that time, and he vehemently rejected the much higher age proposed by geologists, amongst them Charles Darwin. Kelvin had such a high esteem that few dared to oppose his view. But in fact, Darwin was closer to the truth than Kelvin was, because the latter didn’t know about radioactive decay generating vast amounts of heat.

The debate whether we have a free will is an old one.
Classical experiments produced serious doubt about this, although our minds tell us differently. Take the desire to move a finger to scratch at an itch. Before we actually do so, the brain has already sent signals to set this finger in motion. Those signals are even detectable before the person is aware of the desire to move that finger. The conclusion could be, that the finger was not moved at free will, rather, the brain took that decision independently. Moving a finger to start a scratch is not a big deal, but life-saving (or life-ending) decisions are. And even for these, brain signals precede the actual and conscious thought.
So do we have free will or not?

It finally becomes established that sleep is even more important for health and happiness than once believed. Here are some facts:

• The average number of hours of sleep that a person needs at night is in part regulated by their genes.
• When school starts an hour later in the morning, grades of the pupils go up. An exam taken at 11 AM will give better results than at 8 AM. people aged over 65 are generally less tired than people aged between 15 and 24.
• Depression more often results from chronic lack of sleep, than the other way round. Treatment of sleep disorders can both avoid and treat depression conditions.

And yet...

The saying 'is the glass half-full or half-empty?' has always riddled me.
Let me explain.
It is supposed to describe a person with an optimistic or a pessimistic view. But what is what?
Suppose a person sitting at a bar with a half-full glass in front of her. She can contemplate on life in general, and on the fact that her glass is filled with half of its original content.

Recently, a neurobiological study hit the scientific headlines. Its authors had set out to determine, once and for all, if the brains of men and women were different. They measured ten key factors that had previously been described to differ between the two genders. This time, over 1400 brains were compared. The results showed that, instead of a clear distinction, the ten key factors of brains of men and women mostly overlapped, though there were indeed more 'female-like' charateristics in women's brains, and more 'male'like' in those of men.