Intelligenta djur
Läste en artikel som handlade om hur katter tänker och upplever världen annorlunda. T.ex. arbetar katter mer med absoluta koordinater där de är i centrum, t.ex. om man gömmer en leksak under den vänstra av två likadana lådor medan katten ser på och sedan flyttar dem bägge (inklusive leksaken) lika mycket åt vänster ( när katten inte ser på ) så letar katten när den får komma tillbaka till rummet bakom den högra skärmen eftersom det var där i rummet i förhållande till katten som leksaken gömdes. Vi människor hade mer naturligt lagt på minnet att föremålet gömdes i den vänstra lådan. Man har tydligen också kommit fram till att katter kan räkna ungefär till 7. Något annat som kan vara intressant att veta är att katter ju ser väldigt bra i mörker men de ser inte färger lika bra som människor, de ser ungefär som en människa som har röd-grön färgblindhet.
I övrigt när det gäller djurs intelligens så finns det ett test som ofta nämns som kallas spegeltestet där man fäster ett märke någonstans på djuret (när det inte märker det) och sedan ser om det upptäcker det när det ser sig själv i en spegel (dvs att de förstår att de ser sig själva). Detta är det bara ett fåtal djur som klarar av och testet sägs bevisa att djuret har ett slags självmedvetande. En människa klarar detta ungefär vid 18 månaders ålder, medan inget av våra vanliga husdjur klarar det. Bland djuren så är det hominiderna (människor, schimpanser, gorillor och orangutanger), flasknosdelfiner, späckhuggare, elefanter. Men det är ett djur till som lite oväntat klarar detta och det är skator, vilket också är det enda icke-däggdjuret som klarar detta. Så känn dig inte alltför överlägsen nästa gång du ser en skata :-)
Vart tog alla bin vägen ?
Läste i Scientific American om det man kallar CCD (Colony Collapse Disorder) och den senaste forskningen om detta. CCD handlar om att extremt många bin plötsligt dör utan att man först hade en aning om varför, framför allt sker detta i USA men också i Europa. Det handlar om allt från 25% till 90% av alla bin beroende på vilken region man ser på. Detta är naturligtvis väldigt allvarligt eftersom bina används för att pollinera en mängd grödor som används som mänsklig föda.
Tydligen har man nu kommit fram till vad som kan vara orsaken eller i alla fall en del av orsaken. Det har visat sig att i de flesta kolonier som genomgår CCD har man påvisat ett virus IAVP (Israeli Acute Paralysis Virus). Det som jag tycker var intressant var att man i artikeln pekade ut att USA har haft förbud på import av bin från andra länder ända sedan 1922 och fram till 2005 då påtryckningar från bi-industrin om att man behövde mer bin gjorde att man hävde detta importförbud och började importera bin från Australien till USA.
Image by: Antonio Machado (CC - by-nc-sa 2.0)
Man tror att dessa importerade bin kan vara vad som introducerade IAPV till USA. Tål att tänka på att man inte ska leka med naturen hur som helst; den kan slå tillbaka värre än man kunde tänka sig. Ett annat problem nu när viruset är introducerat är att bin inte kan vaccineras eftersom deras immunsystem inte fungerar som hos oss däggdjur. Men man forskar på om man kan odla fram bin som är resistenta mot viruset. Biodlarna har också börjat använda sig av tekniker för att förhindra spridningen av viruset så mycket som möjligt t.ex. genom att desinficera kupor innan man låter nya kolonier flytta in, och man har börjat ge bina extra tillsatser eftersom de ofta får pollinera enorma fält av den samma grödan vilket gör deras kost extremt enahanda jämfört med vad vilda bin får.
Som exempel på vad bin betyder är värdet på odlingen som till fullo är beroende av pollinering från bin i USA mer än 15 miljarder dollar (~120 miljarder SEK / ~100 miljarder NOK).
Ferrofluid disaster
Just for fun I bought some ferrofluid to play with. It's quite cool to see those spikes when moving a magnet around. Unfortunately even though I decided to try to be careful (because this liquid can stain things it get in touch with) I managed to screw up this experiment badly :-) I had poured the liquid into a different container (a glass) to experiment with it but when I was done and was going to pour it back into the original glass bottle I forgot that I had put the magnet a bit too close to the bottle (yes that was obviously stupid, I know) Suddenly they smashed together like a magnet do when it's close enough to something it likes to stick to, and SPLAT !! I got ferrofluid all over my face and around in the room... I fortunately managed to avoid my eyes, and I managed to get most of the stains out of my face.... Well so now I only got to play with it once :-( , but well it was quite an exciting single experiment !.
I read on the bottle that it's relatively safe, whatever they mean by "relatively". Too bad I had to wait for weeks to get this small bottle just to splash it all over my face...
But well, I also bought several other magnet toys so I have things to play with.
I might put up a small video of the ferrofluid experiment later. Unfortunately I had turned the camera off when the incident happened so you can't see that :-)
Update: Video (2:05 30MB mpg).
Pollution
During the Olympics in Beijing there have been quite a lot of discussion about the bad air in Beijing. And as I have myself visited Beijing several times I can say that the pollution is something that you definitely notice and can be quite bad at times. It's quite boring when you do not see the blue sky for many days in a row. But it's also shifting a lot, suddenly the air is very clear.
By the way here is an image of me in front of the olympic stadium which was under construction about one year ago:
There are official measuremnts of the air quality in Beijing that can be seen at MEP, while both BBC and Associated Press are making their own measurements.
The figures differs a bit and of course there can be big local variations, but until now AP has measured an average value of 326 micrograms per cubic meter of PM10 which is the most common measurement for air pollution. You can read more about PM10 at Wikipedia but one reason for importance of this measurement is that it measures particles with a size smaller than 10 micrometers, which is small enough to settle in the lungs and cause health problems. BBC's values are a little lower with maximum values around 300, also according to BBC the yearly average is around 89. The official government data is around 160 under the olympics so far. Nevertheless it can be interesting to compare these values with other cities and your own local area.
BBC also mentions that the yearly average for London is 21. The most polluted city in the world, Cairo has a yearly average of 169, thats almost double the average of Beijing.
I found an article with numbers from Linköping in Sweden which is not far from where I grew up, there the numbers for the yearly average ranges from 18-26 depending on location in the city. Perhaps the numbers can't be compared, but just looking at them it seems that London and Linköping is equally polluted, I find that hard to believe but anyway they are far from Beijing. In Sweden the yearly average can not be above 40 without actions being taken.
Looking at the city where I live (Oslo, Norway) one can see that the yearly average is around 25, and the report I looked at actually had data back to the 1970's and it's interesting to note that the PM10 values for Oslo are now only a third of what it was then, the average for 1971 for example was 74. In the 1980's it was around 40-50, in the early 1990's around 30. The same report also looks at SO2 where the measurements go back to the 1950's with values around 300-400 micrograms per cubic meter, and in the early 2000's the values were down at only 4-5 micrograms per cubic meter. NO2 was also down by the way. I was not aware that the air is so much better now (at least when looking at those three pollutants) then a few decades ago, interesting... But I am just looking at some numbers, how much of an improvement this really means I can't say. Anyway all reports about Oslo and daily measurements can be found at luftkvalitet.info.
Well enough numbers and measurements, I am going to watch some Olympics instead :-)
The barometer problem
I found this story on another blog:
Some time ago I received a call from a colleague. He was about to give a student a zero for his answer to a physics question, while the student claimed a perfect score. The instructor and the student agreed to an impartial arbiter, and I was selected.
I read the examination question: “SHOW HOW IT IS POSSIBLE TO DETERMINE THE HEIGHT OF A TALL BUILDING WITH THE AID OF A BAROMETER.”
The student had answered, “Take the barometer to the top of the building, attach a long rope to it, lower it to the street, and then bring it up, measuring the length of the rope. The length of the rope is the height of the building.” The student really had a strong case for full credit since he had really answered the question completely and correctly! On the other hand, if full credit were given, it could well contribute to a high grade in his physics course and to certify competence in physics, but the answer did not confirm this.
I suggested that the student have another try. I gave the student six minutes to answer the question with the warning that the answer should show some knowledge of physics. At the end of five minutes, he had not written anything. I asked if he wished to give up, but he said he had many answers to this problem; he was just thinking of the best one. I excused myself for interrupting him and asked him to please go on.
In the next minute, he dashed off his answer which read: “Take the barometer to the top of the building and lean over the edge of the roof. Drop the barometer, timing its fall with a stopwatch. Then, using the formula x=0.5*a*t^^2, calculate the height of the building.” At this point, I asked my colleague if he would give up. He conceded,and gave the student almost full credit.
While leaving my colleague’s office, I recalled that the student had said that he had other answers to the problem, so I asked him what they were.
“Well,” said the student, “there are many ways of getting the height of a tall building with the aid of a barometer. For example, you could take the barometer out on a sunny day and measure the height of the barometer, the length of its shadow, and the length of the shadow of the building,and by the use of simple proportion, determine the height of the building.”
“Fine,” I said, “and others?”
“Yes,” said the student, “there is a very basic measurement method you will like. In this method, you take the barometer and begin to walk up the stairs. As you climb the stairs, you mark off the length of the barometer along the wall. You then count the number of marks, and this will give you the height of the building in barometer units.”
“A very direct method.”
“Of course. If you want a more sophisticated method, you can tie the barometer to the end of a string, swing it as a pendulum, and determine the value of g at the street level and at the top of the building. From the difference between the two values of g, the height of the building,in principle, can be calculated.”
“On this same tact, you could take the barometer to the top of the building, attach a long rope to it, lower it to just above the street, and then swing it as a pendulum. You could then calculate the height of the building by the period of the precession.”
“Finally,” he concluded, “there are many other ways of solving the problem. Probably the best,” he said, “is to take the barometer to the basement and knock on the superintendent’s door. When the superintendent answers, you speak to him as follows: ‘Mr. Superintendent, here is a fine barometer. If you will tell me the height of the building, I will give you this barometer.”
At this point, I asked the student if he really did not know the conventional answer to this question. He admitted that he did, but said that he was fed up with high school and college instructors trying to teach him how to think.
It's just a story but I think it's quite nice :-). It exists in many different variants, and snopes.com has dated the first known version of it to 1958.
When the sun dies... when will it get dark ?
Sometimes you hear that if the sun goes out it takes about 8 minutes until we notice it here on Earth as that is the time it takes for the light to reach us.
However this is not exactly true, it would be if the sun suddenly vanished or if the view was entirely blocked for some reason. But if you talk about the sun dying like a fire dies when there is nothing more to burn or like a light bulb dies out after you cut the power it will take much longer than 8 minutes for us to notice. So if suddenly the fusion process inside the sun stopped, how long would it take until there was no light ? Actually approximately a million years, and to a human that is quite a difference, so if the fusion stops I don't think you should be very worried :-). However this was something that was mentioned in a radio program, it would be nice if could find a source on the net that mentioned this.
Cold and pipes
Yesterday I was home from work due to a cold. I have been drinking hot tea all day, at least it feels better...
For some time I have thought about gravity feeding my skimmer (that is let the backflow from the main tank flow into the skimmer instead of having a pump doing that work). So I tried it, this is the before image:
But what I was a bit worried about turned out to be true; the gravity pressure was far from enough to feed that big skimmer, it could work if I dropped a secondary safety outlet, but I do not want to risk flooding the tank so I went back to my old setup again. Or almost because I do not have a straight connecting piece so I ended up with a blocked t-piece, looks a bit stupid but I'll fix it later :-). They are not glued and may thus leak slightly, but that's no problem as it's above the sump.
Earth Climate
Considering the debate about the global warming there are some curiosities that is interesting to know.
Did you know that if you compare to the historic climate of the earth that we have an unusual amount of ice at the moment? We have permanent ice at both the poles, 10 % of the area of our earth is covered by ice and 75 % of all fresh water is ice. Actually the most common state of our planet has been to have no permanent ice at all. Technically we are currently still in an ice age.
Regarding the discussions about the global warming it not really about the current state of the temperature it's about the change.
Just like Michael E. Mann comments in this article:
Its not the absolute state as much as the rate of change, which presents the real challenges and threats.
By the way if you have a good idea about how to remove anthropogenic, atmospheric greenhouse gases you can win a price of 25 million dollars at the Virgin Earth Challange. :-)
Skimmer broken
When I got home from work today I noticed that only one of the pumps on my new skimmer produced any bubbles, so I was a bit worried that it had already broken. That would be a surprise because these pumps are of very good quality and my previous skimmers ran for years without a single problem ( that means 24 hours a day for several years ) before I sold them when I got this new skimmer. And it turned out to not be such a big problem with the pump, when I reattached it from the skimmer body and opened it I saw that it was just clogged by a big chunk of algae with a jelly like consistence. The whole side pipe of the pump was totally filled with it, the other pump had nothing in it ( I of course had to check that one also to make sure it was not building up in there too ). Usually the algae is just whipped to tiny pieces that follow the skimmage up into the collection cup, but apparently this chunk was a bit larger and more dense than usual. Anyway if I get rid of all the algae I should not need to see this problem again.
It's hard to say yet if the algae is decreasing, but it's for certain that the new skimmer pulls out a lot more waste from the water so it should have less nutrients to use. Once a week I will also try to manually extract some of it.
The Deltec 902 has arrived
Today my new skimmer for my aquarium arrived. I have battled for a long time with algae and even though the meaning of what is the best way to get rid of algae is different I have a feeling that the situation is going to improve with this new skimmer. I have tried so many different ways that this is one of my last resorts. It is not entirely true as I have a few more ideas that can be tried if this is not helping either such as a macro algae refugium or an algal turf scrubber, or replacing the liverock if there perhaps is some problem with it. Nevertheless the previous skimmer I had was definitely too small for the volume of water I had. Actually I had two smaller ones but one was so much better than the other that that the second one hardly did any big difference. I have now replaced both of the smaller ones with the new.
I bought a Deltec 902 skimmer which is a huge skimmer for my aquarium, it's actually rated for aquariums of over 2000 liters in size while my total water volume is closer to 800 liters, but I feel that it's better to have one that is too big than too small, now I can tweak this to not run at full capacity if needed. I started it just an hour ago so I am not sure how to set it yet, I have a feeling that I have to adjust it down later when it starts to skim as it's currently running at 100% air intake. It usually takes some time for it to start pulling out waste.
It was a bit pricey, but on the other hand Deltec equipment can usually be sold at good prices second hand due to it's good quality.
Here it is:
It think it look bigger in reality than on this image though. And on the next image I have connected it and started it.
One downside with the new skimmer is that it is so big that I can't have my wooden table hiding the entire sump anymore, that is irritating but not much I can do about it now. Maybe I can figure out a better solution later, one option is of course to run it outside the sump and I know many do this but I am a bit scared of doing so because if it starts to leak I might ruin the wooden floor of the entire apartment, 800 liters of salt water on a wooden floor is definitely something I do not want, as it is now in the sump a leak is no problem at all as it just flows back into the system and I can adjust it when I notice it without any damage done.