A year and a half into the pandemic, we still do not know exactly where the SARS-CoV-2 virus, which causes Covid-19, came from. The prevailing view so far has been that the virus “spilled over” from bats into humans. But there are increasing calls to investigate the possibility that it emerged from a lab in Wuhan, China, where Covid first appeared at the end of 2019. So what do we know for sure, and what do we need still to find out? We know the sequence of the SARS-CoV-2 virus is close to that of bat coronaviruses . Several decades ago its “ancestor” was circulating in bat populations in southern Asia. But there are still many unanswered questions: we don’t know how the virus arrived in Wuhan, how its sequence evolved to allow human infection, and under what conditions it infected the first people who crossed its path. And for each of these stages, we don’t know whether there was a human contribution (direct or indirect). Zoonotic transmission pathways, in other words the pas
Every year in America, women spend at least US$2.8 billion on sanitary pads and tampons that can take hundreds of years to decompose . Is there a more economical and environmentally friendly way? To find out, we asked Susan Powers , a professor of sustainable environmental systems at Clarkson University about her work comparing the environmental impact of tampons, sanitary pads and menstrual cups. What is a menstrual cup? A menstrual cup is a type of reusable feminine hygiene product. It’s a small, flexible bell-shaped cup made of rubber or silicone that a woman inserts into her vagina to catch and collect menstrual fluid. It can be used for up to 12 hours, after which it is removed to dispose of the fluid and cleaned. The cup is rinsed with hot water and soap between each insertion and sterilized in boiling water at least once per period. A cup can last up to 10 years . Although menstrual cups have been around for decades, they historically have been less popular than pads or ta
When microorganisms – such as bacteria or viruses – infect us, our immune system jumps into action. It’s highly trained to sense and eliminate infections and clear up any damage caused by them. It’s typically assumed our immune systems work the exact same way regardless of whether an infection occurs during the day or at night. But research spanning over half a century now shows our bodies actually respond differently at day and night. The reason for this is our body clock, and the fact that each cell in the body, including our immune cells, can tell what time of day it is. Our body clock has evolved over millions of years to help us survive. Every cell in the body has a collection of proteins that indicate the time depending on their levels. Knowing whether it’s day or night means our body can adjust its functions and behaviours (such as when we want to eat) to the correct time. Our body clock does this by generating 24 hour rhythms (also termed circadian rhythms ) in how cells f
Comments
Post a Comment