1

COVID-19 / Re: How do the Imperial modeling vs Oxford papers compare?

« on: 30/03/2020 17:00:39 »

The modelling paper from the Oxford group makes a large number of assumptions about the homogeneity of the population and the way the agent incubates and spreads. The result of their modelling is a prediction that as many as 50% of the population have already been infected.

This seems extremely unlikely. If the assumptions it makes were true, it's a mystery why America, extremely well connected as it is, is only just now joining the party; the virus would have spread there and delivered big numbers much sooner than it actually has. It's also a mystery how so many people (half the population) could be infected yet there be no corresponding spike in deaths like that which we are now seeing and what has been witnessed in Italy.

On the other hand, the Imperial College paper by Neil Ferguson and his colleagues models how a new agent, to which the population is not immune, is likely to spread. They make various predictions of case numbers over time, and they model 2 control scenarios: mitigation vs suppression (what we are doing now) and ask how they compare in terms of case load.

It's the Imperial study that has informed the government's present approach. Today, the same group have now released a new paper that uses rates of death to back-extrapolate to predict the likely number of cases in 11 countries across Europe. This suggests that 43 million infections have occurred across Europe, 1.7M of them in the UK. This means that the attack rate of infection (the number of people infected as a proportion of the whole) is about 3% in the UK, but much higher in Italy at close to 10%.

They then forward extrapolate to predict how many deaths have been averted by the present control manoeuvres. The answer is an estimated 59,000 people across Europe, 400 in the UK.

They acknowledge that serological assays (antibody tests) are urgently needed to clarify this situation and test the validity of these predictions.

2

COVID-19 / Re: Is there coronavirus hysteria?

« on: 27/03/2020 18:23:54 »

I though they were bats (to eat them that is)

Ozzy Osbourne must be crapping himself...

3

Just Chat! / Re: Latest Forum Updates and Upgrades

« on: 24/03/2020 11:22:16 »

MARCH 2020 - CORONAVIRUS SPECIAL UPDATE!

Hello everyone. I hope that you are all keeping well and we thank you for your contributions to this forum, especially the moderators who do a wonderful job and all deserve our wholehearted gratitude.

Regulars may have noticed that we have taken the unusual step of creating a special new board to accommodate the enquiries we have been receiving about COVID-19.

We felt this was justified because this is a specialist topic that is generating a high volume of traffic and will be easier for us all to curate and browse with all of the posts gathered together in that venue.

Could I ask, therefore, that if you decide to start a new topic relevant to COVID-19, please use the above-linked board to post it.

Many thanks, and stay well!

4

COVID-19 / Re: Why is the coronavirus fatality rate in Germany so low?

« on: 21/03/2020 12:26:49 »

This is most likely to be a statistical artefact of the testing.

The Germans have tested a lot of healthier people, including a lot of people from ski resorts.

Fitter, younger people tend to go skiing; older people in poor health do not (they board the Diamond Princess). So although the detection rate is high, the risk of severe disease is low, giving the impression that Germany is somehow special.

5

COVID-19 / Re: Will pneumonia vaccination help to protect people who catch Coronavirus?

« on: 13/03/2020 12:43:24 »

Yes and no.

Pneumovax (or equivalent) triggers an immune response again the bacterium Streptococcus pneumoniae, which causes pneumonia as well as sepsis and meningitis. As such, it will not drive an immune response against coronavirus, so a pneumonia vaccine recipient remains susceptible, and you could catch coronavirus.

BUT - frequently, people who suffer viral pneumonia - classically caused by the flu, although other viruses are also available (!) - the damage to the airway defences caused by the virus renders a person more susceptible to subsequent so-called bacterial superinfection. This means a bacterial infection on top of the initial viral infection. Staph aureus is a common cause of this, and the pneumonia vaccine won't help against that, but some people may develop a Strep pneumo infection. If they have received the Strep pneumonia vaccination, this risk might be mitigated.

6

The Environment / Re: How does science contribute to the circular economy?

« on: 08/03/2020 12:09:21 »

The point of a circular economy is that you design materials from the get-go with their end-of-life in mind.

Hitherto, we have given precious little thought to what to do with things when they break or are no longer useful. As a result, we end up trying to retrofit a recycling plan to products once they have already accumulated into a problem.

7

COVID-19 / Re: Is viral pneumonia result of immune reaction or viral damage?

« on: 07/03/2020 22:36:19 »

Both.

Viruses are obligatory intracellular parasites, meaning that they rely on invading and hijacking our cells in order to replicate. When they do so, they usually compromise the cell, leading to its ultimate destruction. As such, viral infection leads directly to tissue damage; if this is in the lung, that's a pneumonia.

At the same time, viral replication in cells leads to the production of various cellular alarm signals called cytokines. These attract the immune system, which then sets about destroying virally-infected cells; but in the process it usually also causes bystander damage to adjacent healthy tissue. This is a pneumonitis.

Both phenomena will occur at the same time; usually the degree of damage is low, but in some cases it can be severe. The evidence we have is that the 1918 Spanish flu pandemic strain (H1N1) provoked just this sort of immune overdrive, leading to catastrophic lung damage, especially in people with healthy immune systems. This is, we believe, the main cause of death in these people.

8

Physiology & Medicine / Re: Could we induce savantism?

« on: 25/02/2020 10:48:46 »

Well, researchers have invented a "thinking cap" - electrical stimulation of the brain enabled subjects to solve a problem that the majority previously found impossible: https://www.thenakedscientists.com/articles/science-news/electrical-brain-stimulation-boosts-lateral-thought

9

Technology / Re: Could regenerative braking help with air pollution from car brakes?

« on: 02/02/2020 22:52:46 »

Brake dust apparently makes up 20% of pm2.5 pollution:

Also relevant is our recent interview with Liza Selley showing the pro-inflammatory effects of brake dust exposure.

10

General Science / Re: Re: General points about essay writing

« on: 21/01/2020 14:03:19 »

I didn't know Pidgin was used by many exam boards and universities.

11

Physics, Astronomy & Cosmology / Re: Are metals good heat conductors because they are good electrical conductors?

« on: 13/01/2020 21:39:16 »

He's right: https://www.thenakedscientists.com/articles/science-features/thermoelectric-generators-tegs

The electrons in a metal exist as a delocalised "sea" surrounding the pool of positive protons that are the atomic nuclei. Thus the electrons can move about freely, which gives the material its electrical-conducting properties.

But since these particles are mobile, when they are given thermal energy they will vibrate and transfer their momentum to other adjacent particles; the hotter they are the greater the amplitude of their oscillation and hence the greater the distance over which they transfer kinetic (heat) energy within the material.

Consequently, with some rare exceptions, materials that are good electrical conductors are also good thermal conductors. The electrons, being numerous and mobile, tend to be a major means by which heat is transferred.

12

General Science / Re: Can I turn Pixie into a diamond?

« on: 17/12/2019 15:12:57 »

Could use a vapour deposition process by boiling off the cat and piping the carbon-rich gaseous products into a reactor... Not tried this, so have no idea of real feasibility. 

13

General Science / Re: Can fire cast a shadow?

« on: 16/12/2019 22:47:22 »

Hi Neil

We did this kitchen science experiment on dark flames on the radio show; it deals with some aspects of your query.

We also did this experiment to show CO2 casting a shadow owing to the effects of refraction. This is also relevant to the question you are asking.

14

Physics, Astronomy & Cosmology / Re: What will the Event Horizon Telescope reveal?

« on: 15/04/2019 19:27:14 »

Here's the special podcast featuring Cambridge University's Carolin Crawford, from the Institute of Astronomy, updating the details of the EHT findings and answering some of the questions raised here on the forum

https://www.thenakedscientists.com/podcasts/short/eht-sheds-light-m87-black-hole

15

Chemistry / Re: If i dry-distil sodium acetate, will i get acetone?

« on: 23/02/2019 09:43:29 »

No, that won't work.

You're right that reacting baking soda (sodium biocarbonate - NaHCO₃) with acetic (ethanoic) acid - (CH₃CHOOH) will produce sodium acetate NaCH₃COO, which is the stuff used to flavour salt and vinegar crisps.

But acetate is in oxidised form and you would need to reduce it to produce the ketone (acetone).

I did see one claim that if you hear acetate salts to a reasonably high temperature (over 400C) and condense the vapour you'll get acetone. I cannot corroborate this though, and I've not fact-checked the claim.

Calling all chemists! Is this right, and what's the mechanism?

16

Physics, Astronomy & Cosmology / Re: What is the difference between astronomy and cosmology?

« on: 20/01/2019 12:44:56 »

Okay, I'll give this a go:

Astronomy is an observation-based discipline that looks at the Universe and uses various tools to make measurements which may, in turn, inform, support or refute predictions made by theoreticians including cosmologists. The latter are physicists who uses models, maths and observations to build an understanding of how the Universe behaves.

17

Just Chat! / Re: Latest Forum Updates and Upgrades

« on: 16/01/2019 23:36:38 »

HAPPY NEW YEAR - First Update of 2019

Hello everyone; I hope you all had a very pleasant Christmas and New Year. This year I managed to avoid breaking the website over the holidays, which turned my holiday last year into a week of hell, which some of you might remember!

This is a brief note about a couple of updates and upgrades that we have made over December and the first part of this month:

1) Cookie consent opt-in

We've always been very clear in our privacy policy page regarding how we operate on this website, but to make this even more transparent we introduced an opt-in pop-up.

You'll see this appear at the bottom of the page as a black bar with a green button. This contains a link to the privacy page so that you can review how we operate, in case you need to refresh your knowledge.

You will only be required to opt-in once. As soon as you do so, the system remembers you (unless you clear your browser data or switch computers or to another browser platform) and will not pester you again.

2) Notifications of new Naked Scientists programmes and articles

We implemented a notification system that you may choose to sign up to; this will pop-up a small window in the bottom right of your screen when the Naked Scientists publish specific types of content including new radio programmes or podcasts and science feature articles.

The first time you visit the site in your browser you will see a small red bell icon at the bottom right of the screen. Clicking on this produces a menu that enables you to elect to sign up to our notifications, or block them.

If you do sign up, we promise that you will not be pestered by this system. We have purposefully set it up to flag up only a small amount of our best content. We anticipate that we will produce only one or two such pieces every day or two.

You may opt out of the system by selecting "block" at the time of sign-up, or by visiting your browser settings and applying a block against our notifications from there.

3) "Tags" has been fixed.

We have fixed a long-term bug in the tagging system. The box inviting you to "add some tags to your post" at the time when you first create a new thread was failing to create the tags that were entered.

This has now been resolved. We tracked down the error and have resolved it, so do please resume using this system.

Adding tags to your posts makes them far more visible on the site and via the tags menu, meaning that they will most likely garner greater visitor engagement.


Lastly, thanks everyone for your energy and contributions to the forum, especially the moderators, and helping us to create what is an amazing place to learn.

Best wishes for 2019!

Chris

18

Technology / Re: How does a fingerprint reader work?

« on: 12/01/2019 21:27:29 »

Put simply, these devices work in three main ways: imaging, electrical/capacitive fingerprinting and sonic fingerprinting. The complexity and recency of introduction occur in that order.

In imaging, which is the oldest but also the weakest (easiest to fool), a light source at an angle to the skin surface emits a beam or light which reflects off the skin surface and reflections are focused by a lens and detected by photosensitive surface. The pattern of reflections is stored as a 2D image and used to authenticate the user. It's easy to fool because anything that produces the correct pattern will activate the detector.

In capacitative detection, the device compares the electrical capacitance profile of the skin surface, which will change across the skin surface owing to the patterns of ridges and folds. As the pattern of ridges and folds will vary so the capacitance function will vary; this capacitance variation pattern can be used to authenticate the user.

The most recent introduction is an ultrasonic approach. This uses an ultrasound source to bounce sound waves off the surface and store the reflection pattern; this is the hardest to fool but works a bit like the imaging system: the sound waves bounce off the topography of the skin surface in different ways according to the ridge pattern.

I hope that explains things for you?

19

Physiology & Medicine / Re: What could cause a too high potassium count?

« on: 08/01/2019 07:55:00 »

You have referred to the most common causes of hyperkalaemia (raised potassium). For clarity, these are:

Renal failure (acute or chronic)
Antihypertensive drugs (beta blockers, ACE inhibitors)
Diabetes
Excessive potassium ingestion

These are also other, rarer causes like adrenal insufficiency (Addison's disease) where the adrenal cortex fails to produce adequate mineralocorticoid (pro-sodium-elevating) steroids; this leads to hyponatraemia and hyperkalaemia.

Have all of these been excluded?

20

Just Chat! / HAPPY NEW YEAR 2019!

« on: 01/01/2019 09:32:48 »

My very best wishes to everyone; welcome to 2019; let's hope it's fun, prosperous and productive for us all!

What's everyone up to today?