Hydroxychloroquine is an effective drug for the treatment of diseases like lupus and malaria and because it is used off-label for maladies that act in a biologically similar way to how COVID-19, caused by the SARS-CoV-2 virus, acts in the body, there has been discussion that clinical trials might show it having a positive therapeutic impact.

Could it prevent COVID-19, though? A clinical trial of health care workers finds that it does not, though the good news is that because the trial was health care workers they had low rates of infection anyway, likely due to other prevention measures. Masks, hand-washing, and social distancing work.

At a time when sue-and-settle activist groups like Center for Food Safety continue to claim scientists - across the private sector, non-profits, and government agencies - are colluding to poison us by allowing safe pesticide use, their messaging is being ignored by more consumers than in decades.

To estimate infection rates of viruses like SARS-CoV-2, immunologists use a basic reproduction number, known as R0 (pronounced “R naught”) - an expression of the number of people likely to catch a disease from one contagious person - and a Susceptible-Infected-Removed (SIR) model.

Yet as we have seen, those are only telling part of the science story. Coronavirus is in the same family as the common cold and for many COVID-19 will be just like the cold, and can spread like the cold. But when it comes to successful transmission, viruses only win they can optimize their aptitude to survive and reproduce in given conditions - which means they lose if we can optimize disease control measures.

Particle Physics deals with the study of the elementary constituents of matter, and the interactions that they withstand. When non-insiders hear of elementary particles and the experiments that study them, probably their mind goes to experiments at the Large Hadron Collider, CERN's giant accelerator of protons and heavy ions that produced the collisions used by the ATLAS and CMS experiments in 2012 to discover the Higgs boson. The association with LHC and the Higgs particle is very likely because that discovery took the media by storm when it was announced, and rightly so.

In large systems of interacting particles in quantum mechanics, groups of particles can begin to behave like single particles.

Physicists refer to such groups of particles as quasiparticles and while they live, they are useful in helping us understand superconductivity and superfluidity. But many quasiparticles die after less than one second. 

What kills them? How do quasiparticles die?

A new paper goes beyond the usual suspect - quasiparticle decay into lower energy states - and identifies a new culprit: many-body dephasing.

In April, the editors of the Oxford English Dictionary did something unusual. For the previous 20 years, they had issued quarterly updates to announce new words and meanings selected for inclusion. These updates have typically been made available in March, June, September and December.

In the late spring, however, and again in July, the dictionary’s editors released special updates, citing a need to document the impact of the COVID-19 pandemic on the English language.

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.