Why are some humans cruel to people who don’t even pose a threat to them – sometimes even their own children? Where does this behaviour come from and what purpose does it serve? Ruth, 45, London.

Humans are the glory and the scum of the universe, concluded the French philosopher, Blaise Pascal, in 1658. Little has changed. We love and we loathe; we help and we harm; we reach out a hand and we stick in the knife.

We understand if someone lashes out in retaliation or self-defence. But when someone harms the harmless, we ask: “How could you?”

Humans each have 23 pairs of chromosomes, the 23rd of which determines sex. Females carry two X sex chromosomes, males carry one X and one Y chromosome. Yet this male chromosome carries genes that females lack and those male genes are expressed in all cells of the body, but their only confirmed role has been limited determining male or female.
More than 18 percent of U.S. adults claim they do not have access to adequate food from day to day, according to a new paper, which more than doubled between 1999 and 2016. The result: Higher obesity.

People got fat from not enough food?

There are obvious confounders, namely recall bias - and it's hard to reconcile an obese person stating on surveys they don't get enough to eat with biological reality. Scientists know that the only diet that really works is fewer calories. In 100 percent of studies people who consume fewer calories than they burn lose weight. They don't gain it eating less food. 

Dr Tommi Markkanen, an expert on the False Vacuum has kindly answered these questions in an email interview:

1. Does a false vacuum decay due to quantum tunneling have a realistic chance happening in my lifetime or already be on its way?

The answer is a resounding ‘no’. I’m assuming the question is referring specifically to the Standard Model of particle physics for which the likelihood of such an event can be reliably estimated as all input parameters are known to high accuracy. The probability of vacuum decay as predicted by the Standard Model is so mindbogglingly small that in every practical sense there is no chance of this happening.

With unemployment at its highest rate in three decades, almost a million Australians are experiencing the anxiety of being out of work. Even more are underemployed, and more still holding on to jobs for now, not knowing if that will last.

If you feel secure in your job, you are lucky. Because the psychological fallout of job insecurity can last a lifetime.

W bosons, what are they? To answer this question, let me first tell you that our world is made of matter held together by forces. If you look deep within, you will realize that matter is essentially constituted by "fermions": quarks and leptons, particles that possess a half-integer unit of spin, in a certain meaningful system of measurement units. Forces, on the other hand, are the result of fermions exchanging different particles called "bosons", particles that possess integer units of spin.
Do you believe that COVID-19 was created by Bill Gates so he and his Big Pharma pals could get rich selling a cure? Do you believe career government employees are exaggerating COVID-19 to sway the election to their side?
Yaws is a childhood disease causing highly infectious skin lesions. It is spread by touch and, in advanced cases, can leave sufferers with severe bone disfigurement.

While it is easily curable in its early stages today, and is almost eradicated, the bone disfigurements are irreversible. Yet 4,000 years ago there was no treatment and a new study looked at skeletal remains from the Man Bac archaeological site,  excavated in 2005 and 2007, in the Ninh Bình Province of Vietnam. After seeing what might be yaws on a photograph of Man Bac remains, a team of experts confirmed it - and University of Otago graduate student Melandri Vlok found a second example of the disease. 
A new study shows there is even more reason to worry about the Zika and chikungunya viruses and the pests that spread them; increased risk of neurological diseases like stroke.
A new mathematical model seeks to predict economic performance of crops, which will allow breeders to obtain the plants with the highest possible quality. 

Using even the most advanced legacy tools, it is very difficult to create a new variety of plants and it usually takes 10-12 years. Using genomic selection models, this process can be accelerated several times, finds the new study, using a new mathematical model for predicting crop phenotypic traits as a function genotype.