1

Geek Speak / Re: Windows 7 full version or original?

« on: 10/09/2020 19:09:13 »

Get the proper - trustworthy - impression from MS - use the create install media system:

https://www.microsoft.com/en-us/software-download/windows7

You can input your key; it will release the software if the key's valid.

2

COVID-19 / Re: Could the infection rate be significantly underestimated?

« on: 17/04/2020 16:19:00 »

It's highly likely that infection rates are higher than we thought or think. Partick Vallance (UK chief scientific officer) suggested at one point that the ratio of deaths to actual infections might be close to 1:1000; so with 10,000 plus deaths there may well have been 10 million cases in the UK already.

What will solve this is widescale serological testing. Once we can test the UK at scale for antibody to infection and discover how many people have really had it, we can refine and reinforce our models and control measures accordingly. Personally, I suspect that there has been considerable widescale spread in the community already.

3

COVID-19 / Re: Is there modelling of the consequences of wards cleared for Covid-19?

« on: 17/04/2020 16:15:58 »

This is Chris Whitty's "secondary deaths" which are health consequences not directly caused by Covid-19 but instead indirectly linked to it. For instance, people having a heart attack who cannot get to hospital because all the ambulances are tied up being decontaminated after ferrying Covid patients to A&E. Also, people with planned treatments judged too risky under the circumstances may find their therapy deferred and they are forced to accept less than gold-standard treatments.

Is this happening? Yes. Do we have evidence? Not yet, but I suspect it will be accruing. For instance, a cardiologist friend reported that his presentations and case load for heart failure and stroke had plummeted. But this does not mean people have suddenly stopped having heart failure, they are instead deteriorating in the community, too fearful to come to hospital. The result may be people who go beyond the point of no return and cannot be rescued back because they present too late when they eventually are seen.

4

COVID-19 / Re: Why ventilate covid patients in a prone position?

« on: 13/04/2020 22:20:03 »

I'm very grateful to my friend and colleague Dr Ari Ercole, from Cambridge University / Addenbrooke's Hospital, who provided this extremely clear explanation:

As far as proning is concerned this has gone back years with nobody finding a survival benefit (although it improves oxygenation) until the attached study¹ which changed things suggesting it was a good idea if you do it early in ARDS and combine it with modern ventilation strategies which try to protect the lungs from mechanical trauma.

The way it works is through improving V/Q [Ventilation / perfusion] mismatch. Under normal circumstances, gravity means that the lowest (or back if you’re lying down) bits of the lungs tend to get a little more blood flow because the blood pressure decreases with height above the heart. At the same time, the low bits tend to be mechanically collapsed (think holding a damp sponge by a corner- the top is stretched and the bottom squashed). This means we tend to see collapse, pulmonary oedema and consolidation mostly on the lower (/back) bits of the lung. So we have an unfortunate situation where the blood is preferentially going to bits of lung that aren’t aerated very well (although hypoxic vasoconstriction may partially offset this).

Proning reverses that and sends blood to the aerated bits / re-expands collapsed lung. Unfortunately it’s not easy- very hard and dangerous to flip someone critically ill on a ventilator over (risk of accidentally pulling out the endotracheal tube, lines etc). Also there’s a risk of pressure sores and the facial oedema you see is marked. So we usually prone for 16 hours out of 24 or so. A lot of hospitals are putting together ‘proning teams’ because it needs a lot of skilled manpower.

1. Prone Positioning in Severe Acute Respiratory Distress Syndrome, Claude Guérin et al., NEJM 368 p.2159

5

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.

6

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...

7

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!

8

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.

9

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.

10

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.

11

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.

12

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

13

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.

14

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.

15

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.

16

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. 

17

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.

18

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

19

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?

20

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.