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[Music]

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thank you very much for this

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introduction so now you are already

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aware that I'm going to talk about bits

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of paleontology which may sound a bit

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weird for astrobiological science but

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I'm going to show you a bit of how we

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can use some new physical approaches to

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to understand these structures that we

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call micro fossils so micro fossils are

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very interesting for the proposals of

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astrobiology because they are

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morphological signatures of

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microorganisms that were preserved in

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the geological record and they are the

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earliest direct evidence of life that we

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have on earth and this we don't have

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nowadays rocks from the idæan but we do

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have well preserved with rocks from the

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arcane and studies these structures

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preserving these rocks give us also eye

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insight into the pallium governmental

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context bringing us a bit closer to to

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the first organisms and how this these

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artists were able to to to live in this

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ambient that was very different to what

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we know today and it's also interesting

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because we all have an insight of the

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early life the diversity and evolution

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and how life already was able to to to

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be in the Archaean so microprocessors

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are really interesting so we can we know

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that in Mars in the path of Mars we have

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a stable condition so we may have traces

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of life there so let's go look for them

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and this is one of the aims of NASA and

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easie for the next years but if you

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wants to look for life in Mars we need

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also to think so how we identify these

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churches so how these structures that we

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know earth look like and this especially

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if we're talking this about this really

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first micro fossils we have actually not

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a quite answer because every year I have

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new studies coming and quite it's a

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quite big descriptions of which are the

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earliest evidence of life of

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microfossils on earth and we have every

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year new studies claiming that they

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found the earliest micro fossils on

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earth and you feel a big discussions and

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one of the reasons of this is that

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actually micro fossils are quite

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challenging structures to study first

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reason is because they are micro metric

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size structures which means that for for

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analyzing them we require nanometric

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resolution they are organisms that are

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now rocks so they have an homogeneous

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density and this is an important thing

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because most of imaging techniques are

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based in the absorption and absorption

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is directly related to the density of

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the material and we cannot forget that

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this rocks best to billions of years of

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geological processing which means that

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first they are rare we don't have that

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many places on earth that we can find

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the really Archaean well-preserved rocks

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and one important thing is if we are

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going to talk about if these structures

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are really biogenic how we prove that

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what we find in the geological record

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are really remains of life and this is a

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very tricky question because we have a

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lot of structures that look like life

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but they are actually not a biotic

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informant so we have some examples here

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some some silica dialers and we have a

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very famous example of this Allen Hughes

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meteorite that they found the structures

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that look a lot like life bringing this

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idea of how can we prove what what we

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find is really life so the objective of

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my project is to try some new

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high-resolution imaging techniques

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looking for water structure of this

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strip of this of what we find in the

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geological record and looking for

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contributing about this by using the

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secretary to identify them so first

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technique the already introduced also

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called scanning laser confocal laser

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scanning microscopy we took some

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Brazilian micro fossils from 219 million

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years old we put them in this microscope

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we

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Karajan that is the graduated organic

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matter they it has autofluorescence

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property which means that we can image

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the the organic matter and see them in

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3d and we can have images of the the

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preserve of the karagin in microfossils

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we can do this for cyanobacteria we also

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did these to some pollen grains and

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pollens are much more resistant

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structures which which was interesting

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because we saw that actually we had

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different fluorescence wavelengths and

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this means that actually you have more

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than one type of organic matter here and

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this indicates that we may have a

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different level of geochemical

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maturation of this organic matter or

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also that we have different types of

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couraging indicating probably different

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biological compounds that that evoluted

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different during the geological system

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another thing we did we took pieces of

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rocks we we decide to do micro

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tomography we took them to the micro two

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models of the line of the Brazilian

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synchrotron so these are the only pieces

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of rocks we scan them and these are the

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pollen grains I just show you we could

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identify them inside as pieces of rocks

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because they have this Mickey Mouse

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morphology quite easy funded to

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recognize and we was interesting because

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this approach is totally non-destructive

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we just took a piece of rock we put

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there and managed to identify the

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structures but falling Ray's they are

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quite big if we are talking about micro

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posting they have more than 15 nano

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micro meters which is big for all for

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really microorganisms when we look for

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smaller structures we can see some some

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structures with this micro CT but they

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are not so easy to recognize and to

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understand if they are really forces or

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not and the reasons are the same way I

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just said they are we are talking about

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absorption techniques so they are

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homogeneous base and we are talking

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about the micro CT we are not achieving

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nanometric resolution so just a basic

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idea when we are talking about x-ray

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imaging we have an object and when we

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put them under the x-rays they absorb

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x-rays in the absorption of x-ray that

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the set is directly related to density

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so this is the reason that if we put our

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hand in the x-rays we will see the high

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density compounds but we are not really

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be able to distinguish the soft tissues

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the flesh and so on and if we're talking

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about a fossil we I we did this pretty

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in previous work we put a photo finish

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in inner-city scan of hospital and we

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could see some structures but not that

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many information so this is why I'm

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talking about absorption city but it's

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the same city that we do when we go to a

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hospital to do an exam but absorption is

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not the only thing happening when you

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have the x-rays interacting with with

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your object a lot of different things

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happen and the object has actually index

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of refraction that is complex in their

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index of refraction so this part is here

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is related to the absorption as I said

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but we also have this other part here

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that is actually related to another

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physical phenomena that is reflection

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refraction is also going on here so we

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may be able to explore this thing for

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seeing more information so if you have

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choo-choo x-ray waves coming they are in

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phase which means they have the both

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highs and lows together one will pass

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through your object it will be slowed

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down when passing to the object and when

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it's exit exit the object we they will

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not be any more in phase will have this

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phase change now and we can explore this

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to see if it as a contrast for the

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imaging in this take this type of

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approach is called phase contrast so

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coming back again to our fish we had

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this image with absorption city we took

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the same fish we did face contrast CT

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and now I have this image now we can see

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much more in from more more structures

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we can see a lot of different things and

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if you look to the stomach of this fish

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we can find this kind of last meal and

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if you cannot identify what it is I'll

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give you a clue and we did see this kind

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this is to show you how much more

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sensitive these phase countries are for

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forces so

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is really good for our micro sources

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right so let's try to expert

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phase-contrast in microphones so we did

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this and this technique we applied is

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called take over see we joined a

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congress abuse tomography so we did a

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phase contrast nano democracy using

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typography we put some micro process

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from Precambrian so we have this iron

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oxide preserved filaments of microbes we

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took them to the synchrotron source we

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use the six facts big line of the street

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light source and I will show you what we

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get with this technique so first thing

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that is very good we achieve the 52

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nanometer resolution which is great much

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higher than we could get with any other

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x-ray imaging so far we also have now

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the pixel intensity that is related to

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electron density because if the electron

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density of the compounds that gives the

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phase changes so we can extract the

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electron density which give us the best

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thing so we have also our information

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about what are these materials inside

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the fossils so we could identify clearly

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four different compounds in these micro

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fossils we have seen here the Sinica

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matrix we have these more wide

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structures that are more advanced they

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are the iron oxides that we already

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could see in red in the optical

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microscope and we have now the silica

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mixtures with the organic matter and you

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have also some really really low density

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structures that may have may be the

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degradation components the degradation

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cell membranes and septa that we had in

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the filament so just a little video to

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show you how it looks so we have here

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the the pillar of rock we have the

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filaments inside passing through it so

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we can see the the low density

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structures that I will mark here in blue

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we can see the body of the of the

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phosphor determine Green and I'm outside

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in orange and now we can have a 3d

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imaging knowing not only the

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morphological but also the the chemical

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information of this puzzle so we had

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before this image using visible light

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microscope and now we have this image

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much more information is the same

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structure and now we can see some

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features that we couldn't see

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for and we can even find a compound

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which can also help us to understand the

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cessation processes so conclusions using

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this different physical phenomena are

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allowing is allowing us to retrieve

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novel chemical and morphological

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information of microfossils the electron

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density contrasts with we can achieve

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this I cover fee associated with the

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nanometric resolution that we can also

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have with technique is able to give us

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some new insights into the most a lot

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more logical aspects and now we are able

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to start revisiting the biogenic

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secretaire that we design with the lower

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resolution imaging another very

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important thing is that we are talking

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about techniques that have little or no

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simple laws which is very important if

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we think now about bringing sample for

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Mars and we are proposing new approaches

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now for studying the the samples that

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will bring it in the near future for

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months so that's what we're doing

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thank you very much living with a little

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video of the new synchrotron that we are

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building in Brazil so will be open for

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your users soon so I hope some of you

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can go and use and Singleton's are open

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for the community so hope to see some of

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you so that's it thank you thank you

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very much large we have any questions

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I thought your talk was incredible great

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so I a question regarding the

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fossilization process have you maybe

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move this step further to build models

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for diagenesis we didn't but it's a

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possibility we don't have some studies

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that do in situ fossilization and one

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interesting thing would be really

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simulating this and you can measure in

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different times and seeing what happened

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because actually the preservation of

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this microarray music is is not to be

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quite fast doing silica criminalization

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so we still did

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but it's it's it's sure that it's

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possible so it's an interesting idea

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maybe for the future any further

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now this is a limitation of certain

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techniques because we cannot have

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portable synchrotrons so it's true we

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can we have other techniques aiming to

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find this stroke your signatures outside

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but they are limited compared to this

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one so we can have some clues but to

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have a really deep study we will really

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need to be simple so this is the biggest

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limitation for for looking for life any

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further questions okay thank you so much