1

COVID-19 / Re: Can covid tests also detect common colds?

« on: 13/05/2022 00:20:04 »

There are around 150-200 viruses that we classify as "the common cold". Only 4 of them are coronaviruses, so it's not really accurate to say "a cold is a Coronavirus".

You could produce a RAT test that detected one or a couple of the common cold viruses (eg adenoviruses), but it is unlikely that a single RAT test could detect all of them.

I am sure that one of the criteria for a successful COVID-19 RAT is that it did not react to the 4 "Common Cold" coronaviruses.

There are hints that people who have recently suffered from a "Common Cold" coronavirus are slightly protected from COVID-19, as their immune system responds to the family resemblance.
- This may be why children under 2 years old show some benefit from a COVID vaccine, while those 3-5 do not
- Children under 2 have lived during some form of lockdown, and may have had less exposure to the 4 "Common Cold" coronaviruses, and so may have less protection against COVID-19 than slightly older children.

https://en.wikipedia.org/wiki/Common_cold

2

Just Chat! / Re: What is your main area of interest or expertise?

« on: 03/05/2022 23:22:08 »

Philosophy should be the basis of our biggest and most influential decisions.

It has been noted that if you recursively trace the first significant word in a Wikipedia article back to its Wikipedia article, you get back to the Wikipedia entry on Philosophy (in about 95% of cases).

So perhaps Philosophy is the basis of our biggest and most influential Wikipedia articles? (in a roundabout sort of way...)
See: https://en.wikipedia.org/wiki/Wikipedia:Getting_to_Philosophy

3

General Science / Re: spherical implosions

« on: 03/05/2022 22:37:56 »

The Trinity test didn't need a perfectly spherical implosion - just good enough.
- And it worked - but they needed a much more compact arrangement if they were to fit it into a plane.
https://en.wikipedia.org/wiki/Trinity_(nuclear_test)

Another area trying to do spherical implosions today is the US National Ignition Facility, which is trying to initiate nuclear fusion with a spherically symmetrical arrangement of 192 lasers.
See: https://en.wikipedia.org/wiki/National_Ignition_Facility#Tests_and_construction_completion

4

General Science / Re: Is 2 really prime? If so, why isn't 1?

« on: 01/05/2022 04:11:50 »

There are also prime polynomials (if you ignore imaginary zeroes).
- These are important in telecommunications and encryption schemes

5

Just Chat! / Re: Free lectures

« on: 01/05/2022 04:04:08 »

There is certainly a social aspect to university (often centered more on the pub than the lecture hall).
- Some distance education programs actually have weekend or 1-week "in-person" sessions to cover some of the social/physical access components of the course.
- Australia earns a lot of income by training students from other countries at a "Western" university - and this revenue almost dried up during COVID, putting a lot of universities under severe financial pressure, leading some to shed staff.
- There is a fair bit of snobbishness about which university you attended - how could you be so snobbish if everyone had access to the best lectures by the best lecturers?

It is already hard for students to move into tenured professorships - if only the best lecturers were filmed & distributed, there would be no way to practice these skills, and develop the next generation of lecturers
- The current generation of poor lecturers would be out of a job, and their students (and the country) would probably benefit
- The ability to get individual or small-group attention for academic work is of great value, because applying the knowledge is just as hard (and probably more important) than just hearing the knowledge.
- There would need to be an ongoing commitment to tutorials and marking/commenting on student work - tasks that could perhaps be done by phD candidates to earn a bit more income?
- We have a lot of investment in physical capital of universities distributed in different places around the country - physical access to a laboratory will still be important for the physical sciences. Perhaps less so for the Arts.
- Universities would need to focus more on research and supervising research than on lecturing. But funding of research comes from a different bucket of money than tuition; so making this transition would be painful.

I am sure that things could be done better - and it will take the impact of major events like a pandemic to kick us along the path towards something better. Call me an old fuddy-duddy, but I still struggle with a comment I heard about someone learning their science from Tik-Tok...

6

General Science / Re: How to reduce cast iron melting point

« on: 01/05/2022 03:06:41 »

you get diamond powder

Carbon is very soluble in iron.
- Of the different allotropes (forms) of carbon, diamond is stable at high pressures (like > 150km beneath the surface of the Earth). At sea level pressures, graphite is more stable, so diamond is thermodynamically encouraged to slowly turn into graphite (although you can reduce the rate by cleaning it in hydrofluoric acid, with ties up a lot of the loose ends with fluorine atoms)
- One other allotrope is carbon nanotubes, and these have been formed by having tiny iron "seeds", which grow carbon nanotubes.
https://phys.org/news/2012-11-optimize-growth-individual-carbon-nanotubes.html

[Spoiler:]

7

General Science / Re: Is 2 really prime? If so, why isn't 1?

« on: 29/04/2022 10:24:37 »

Spoiler: show

Spoiler Test
Thanks!

8

Just Chat! / Re: Are The Naked Scientists Listeners open to interviews?

« on: 20/04/2022 00:33:23 »

I've sent an email to Karin (academic supervisor). I expect at least a 12-24 hour delay before I get a response.

9

Just Chat! / Re: Are The Naked Scientists Listeners open to interviews?

« on: 19/04/2022 10:51:04 »

Many people get scammed on the internet. My sentiments overlap with the concerns that EternalStudent posted in parallel.

It is important to preserve the privacy of readers/listeners, especially when dealing with a request for contact from an unknown person.

Perhaps glesphlep could reduce the "unknown person" barrier by posting details in this thread of his name, university, course, thesis topic and thesis supervisor. Those details are verifiable.

glesphlep could also indicate what type of communication they are interested in for the interview (eg Zoom, mobile phone, etc), and how long they expect the interview to take. Identify the criteria that would be used to select interviewees.

Perhaps people who have verified this identity could then send a personal message to glesphlep, identifying their general location (eg nearest city in the same timezone), and suggesting a suitable time for a discussion. Maybe mention a few details that will help glesphlep decide whether this person is an eligible candidate.

I suggest that interviewees don't give their personal email or phone number to glesphlep. Once a mutually acceptable time is agreed, the interviewee calls glesphlep. On mobile phones, Caller ID should be suppressed.

Post your interview experiences here - does it sound legitimate?

Attempts to scam forum members will be met with a prompt ban - moderator.

10

Just Chat! / Re: What is your main area of interest or expertise?

« on: 11/04/2022 21:42:19 »

I'm still fairly surprised and impressed that you reply to so many questions or discussions in the Biology sections.

One view of biology imagines it to be a fantastically complex program, coded in DNA.
- The cell represents the computer which executes the program (unlike silicon computers, it also has programs for self-repair)
- You can see parts of the program that are no longer executed, or which have been corrupted by viruses
- Each little computer interacts with others around it, at various levels up to whole ecosystems...
- Not entirely different from the telecommunications systems that I work on...

11

Just Chat! / Re: What is your main area of interest or expertise?

« on: 11/04/2022 03:54:01 »

I studied Electrical Engineering at an Australian university, but I have always had a broad interest in the sciences, mathematics and museums.
- As a youngster, fueled, I think, by electronics magazines and Isaac Asimov's fiction & non-fiction
- I studied a lot of software at university (much easier these days than back then...)
- I have spent most of my career working on software-based telecommunications systems
- In my career, I have had the privilege of traveling to many countries, and even to live in Europe for a year (for work)
- My main science-writing experience outside telecommunications has been on the Naked Scientists forum (not as a journalist or for a museum)
- I try to consider the ethical aspects of a subject, beyond the science itself
- I haven't even tried teaching my gym instructors that force, energy, power and strength are not the same thing.
- I have only contributed one short audio segment to the Naked Scientists podcast, and that was on (pseudo)random numbers.
https://www.thenakedscientists.com/podcasts/short/what-random

PS: I only saw this survey today - not all new topics pop up in my in-tray...

12

Science Experiments / Re: Hookah system

« on: 05/04/2022 23:56:55 »

If the smoke passes through the water in large bubbles, almost none of the smoke comes in contact with the water, and  it has no impact on the content of the smoke.
- This makes it about as useful as a lava lamp - visually stimulating, but doing nothing for your health
- I saw one hookah-user who put a small plastic toy in with the water; it danced around on every breath, amusing his small child...

You need to divide the smoke into very small bubbles, so it has maximum contact with the water
- This will dissolve some chemicals from the smoke
- Including many of the very small smoke particles which can reach deep into the lungs (and even into the bloodstream). These are covered with the unstable products of combustion, which can cause cancer.
- But hydrophobic molecules will pass through the water almost unchanged.

If you want to improve the hookah, put an N95 mask over the pipe...

13

Physics, Astronomy & Cosmology / Re: How does a red-shift affect a black body spectrum?

« on: 05/04/2022 10:38:48 »

An object putting out a black body spectrum is measured as such in all inertial frames of reference.
- Different Frames of reference will see the object as having a different effective temperature.

To take it to the next level: Black holes experience extreme gravitational red shift.
- According to Hawking, black holes "glow" with a black body spectrum.
- The effective temperature varies with the mass of the black hole
- A stellar mass black hole has a temperature measured in nanokelvins
- Which is why stellar-mass black holes take a long time to evaporate.

https://en.wikipedia.org/wiki/Hawking_radiation#Overview

14

Cells, Microbes & Viruses / Re: How can I find tardigrades?

« on: 04/04/2022 23:39:37 »

they seem to prefer drying out occasionally so don’t choose moss that’s damp all the time

There are many soft and squishy critters that would thrive in an environment that is damp all the time. But when it dries up, they tend to die.
- Tardigrades enter a form of suspended animation (a "tun" stage) when conditions get too harsh (eg lack of water). They reanimate when water becomes available. They can thrive in an erratic environment that would kill many other animals their size.

15

New Theories / Re: Is this why Ivermectin appeared to be the answer to Covid?

« on: 03/04/2022 23:34:31 »

I heard another theory about why Ivermectin could potentially reduce COVID impacts (from a friend working in the pharmaceutical industry):
- Ivermectin is known to kill intestinal worms (that is what won the 2015 Nobel prize)
- Intestinal worms are known to tone down the immune system of their host (so the host immune system doesn't attack the worms so strongly)
- Many people in in 3rd-world countries are suffering from undiagnosed and untreated intestinal worms
- So a standard dose of Ivermectin would kill off the intestinal worms. Maybe then the human immune system recovered, and when subsequently exposed to COVID, these patients were better able to fight off the viral infection?
- This would have little or no affect in "Western" countries (where many of the Ivermectin trials have been run), as rates of intestinal worm infection are low, and any cases of worms are promptly treated.

I see it as a logical chain of events, but it's a long way from proof.

16

Cells, Microbes & Viruses / Re: How can I find tardigrades?

« on: 03/04/2022 08:15:28 »

They are small: Up to 0.5mm, so you need to look for them under a microscope
They are fairly transparent, so they will be hard to see
I suggest getting some damp moss, and break it apart under a microscope.
https://en.wikipedia.org/wiki/Tardigrade

17

General Science / Re: Antarctic science greenhouse emissions

« on: 19/03/2022 22:01:49 »

There was a nuclear reactor operating at one Antarctic base for a decade. But due to maintenance problems, it was replaced by diesel generators.
https://en.wikipedia.org/wiki/McMurdo_Station#Nuclear_power_(1962%E2%80%931972)

On a global scale, the population of Antarctica is so low (under 5,000) that their greenhouse emissions are negligible, even if they do consume somewhat more energy than the average for their home nations.
- Of more concern from the local population is pollution from oil spills, rubbish and the risk of invasive species
- The greenhouse emissions of the rest of the world are also significant, which will continue to break up the ice sheets that are important for algae, krill, and whales

18

Physics, Astronomy & Cosmology / Re: Why does luminosity vary predictably in Cepheid variable stars?

« on: 15/03/2022 08:42:53 »

Changes in Luminosity seem to be explained just by changes in surface temperature, not by the variable opacity of the Helium ionisation layer

The visible light we see is from the surface of the star. Depending on pressure vs temperature vs altitude, I could imagine:
- The Helium "switch" could be beneath this surface layer of (mainly) hydrogen, cutting off the surface layer from the underlying heat source, causing the surface temperature to fluctuate. What we see is mostly the changing temperature of Hydrogen.
- The Helium "switch" could be above this surface layer of (mainly) hydrogen, cutting off our view of the surface layer except when the helium layer is particularly transparent, causing the surface temperature to fluctuate. What we see is mostly the changing temperature of Helium.

19

Physics, Astronomy & Cosmology / Re: Why does luminosity vary predictably in Cepheid variable stars?

« on: 14/03/2022 20:46:46 »

This researcher used open-source MESA software to model the behaviour of stars which enter the Cepheid variable phase. He tabulates temperature, radial velocity, etc for several stars he modeled.
http://www.aoc.nrao.edu/events/nmsymposium/2019/contributions/talks/guzik.pdf

Some of his diagrams suggest that an individual star can start oscillating due to one effect, and stop. Then later in it's lifetime, it can start oscillating due to a different effect and stop, potentially entering and exiting this behaviour several times before the star eventually dies.

20

Physics, Astronomy & Cosmology / Re: Why does luminosity vary predictably in Cepheid variable stars?

« on: 13/03/2022 05:52:59 »

There are several groups of variable stars with slightly different period-brightness relationship:
- Type I Cepheids are 4-20 times more massive than the Sun; since luminosity increases as the 4th power of the mass, these are very bright stars indeed.
- Type II Cepheids are around half the mass of the Sun, and very old stars (judging by the very low levels of elements beyond Helium).

In both cases, the ionisation of Helium is thought to be a driving factor:
- When Helium is fully ionised, it is more opaque; when it is only singly ionised, it is more transparent
- When Helium is transparent, it lets out light from the surface of the star, and the outer atmosphere of the star cools and shrinks.
- As it compressed, the outer atmosphere heats up, and more Helium becomes doubly ionised. This has two effects: (1) from outside the star, the light is attenuated, ie the star appears dimmer, and (2) The atmosphere heats up and starts to expand
- As the atmosphere expands, it cools, and the Helium becomes more transparent (ie the star looks brighter from a distance)
- The cycle then repeats

The variable behavior is just a phase that stars pass through. Massive stars like Type I Cepheids burn their fuel quickly, and are likely to explode in a supernova.

See: https://en.wikipedia.org/wiki/Cepheid_variable#Pulsation_model