Very little has been published on VivaGel in peer-reviewed literature. Credit: Morgan/Flickr, CC BY

By Bridget Haire

Dark matter is ill-defined and never detected so how can a group of astronomers say current measurements are off by 50 percent?

Most of the matter in the universe is hidden. It's not stars, it's not planets, it's not dust. No one knows what it is. But it must be something or gravity does not work. That something is the mystery. Using inference, if 4 percent of the universe is matter, and around 25 percent is dark matter (what is the rest? Dark energy, an even more fanciful conjecture) then the 'weight' of  dark matter just in our galaxy is 800,000,000,000 times the mass of the Sun, say a group of Australian astronomers who used a method developed almost 100 years ago for their estimate.

Credit: Ed Bierman, CC BY

By Clive Trueman, University of Southampton

Fish are acutely aware of sea temperature; it’s one of the key reasons particular species of fish live where they do.

As the oceans warm however, many tropical species are moving towards cooler climes. So might the traditional cod and chips one day be replaced by Nemo and chips?

Stick 'em up. Credit: Me2, CC BY-NC-SA

By Toby Miller, Cardiff University

People concerned about human-insecticide exposure have stimulated interest in alternative bed bug control materials, including oil-based pesticides and detergent insecticides.

But how well do they work? Researchers from Rutgers University evaluated the efficacy of nine essential oil-based products and two detergents that are labeled and marketed as 'natural' bed bug control. 

The non-synthetic bed bug pesticides contain ingredients such as geraniol, rosemary oil, mint oil, cinnamon oil, peppermint oil, eugenol, clove oil, lemongrass oil, sodium lauryl sulfate, 2-Phenethyl propionate, potassium sorbate, and sodium chloride, included the following products:

Artistic impression of the Milky Way galaxy. The blue halo of material surrounding the galaxy indicates the expected distribution of the mysterious dark matter. ESO/L. Calçada, CC BY

By Geraint Lewis, University of Sydney

Researchers have uncovered a molecular process in the brain known to control eating that transforms white fat into brown fat, and that impacts how much energy we burn and how much weight we can lose.  

Oxytocin, called the "love hormone" because it has been linked to social behaviors like cuddling, maternal care and pair bonding, is also necessary for female social interest during estrus.

A study Cell Press found oxytocin-responsive brain cells that are necessary for female social interest in male mice during estrus, the sexually receptive phase of their cycle. These neurons, found in the prefrontal cortex, may play a role in other oxytocin-related social behaviors such as intimacy, love, and mother-child bonding. 

by Marc Brazeau, Genetic Literacy Project

Next week, the Environmental Protection Agency is set to approve Enlist Duo–a new herbicide formulation that combines two popular herbicides, 2,4-Dichlorophenoxyacetic acid (2,4-D) and glyphosate (the active ingredient in Roundup), which are used to control weeds.

The pale blue dot. Credit: NASA

By Monica Grady, The Open University

World Space Week is one of a series of events co-ordinated by the UN to celebrate the global nature of space exploration. It was established in 1999.