2009 is coming to its end... and it is time to review the most important scientific contributions of the year.
For this reason the magazine Science has published a special issue with the top 10 breakthroughs of the year (according to Science). And the winners are...
1.- Ardipithecus ramidus. Ardi was an Ethiopian woman, 1.20 m tall... and who lived 4,4 million years ago! It is the most ancient hominid fossil ever found.
2.- Pulsars. Gamma rays Fermi NASA telescope has allowed to detect pulsars. The telescope was put in orbit in 2008, and providing a measurement that was a proof of the relativity theory has been its most important success so far.
3.- ABA receptors. Major advances in the knowledge of the structure of the drought hormone have been achieved during 2009.
4.- Monopoles. Two research group have achieved magnetic pertubations of monopoles from spin ices.
5.- Rapamycin. Rapamycin (a medicine used to prevent transplant rejection) can prolong mammal's life. The experiment was carried out in rats, that prolong their lives between 9% and 14%.
6.- Water in the moon. NASA announced on the 13th November that the Lcross spacecraft sensors had detected water vapour and ice in the moon.
7.- Genetic therapy. Advances in genetic therapy to treat blindness.
8.- Graphene. Latest research about the graphene properties has revealed that this material could replace silicon in chips.
9.- Hubble repair. Hubble repair mission prolonged its life and improved some features.
10.- X-ray laser. Since we reported in a post some months ago, SLAC laboratory started running the first X-ray laser.
And what is the most important discovery for you? Fill in the survey you can find on your right!
Also, you can also find a really interesting and comprehensive podcast about the 10 most popular stories of Science in 2009 (the transcript can be downloaded here).
Friday, December 25, 2009
Wednesday, December 23, 2009
PHD Comics: Laser in Use!
Dont worry. There are real lasers in our optic labs ;).
(click on the picture to enlarge it)
If you want to know how graduate students are living or how life in the lab really is then visit:
"Piled Higher and Deeper - Life (or the lack thereof) in Academia".
PHD Comics
A comic strip by Jorge Cham. In general every 2. or 3. day there is a new phd comic strip online and he hits absolutly the situation :)! Click here if you want to go directly to his most popular 200 comic strips! Enjoy!
p.s. have a visit in our optic labs!
If you want to know how graduate students are living or how life in the lab really is then visit:
"Piled Higher and Deeper - Life (or the lack thereof) in Academia".
PHD Comics
A comic strip by Jorge Cham. In general every 2. or 3. day there is a new phd comic strip online and he hits absolutly the situation :)! Click here if you want to go directly to his most popular 200 comic strips! Enjoy!
p.s. have a visit in our optic labs!
Wednesday, December 9, 2009
Refractive Index Database
Who dont know this problem: you need something urgent but you have to spend two hours until you have found it. In optics, knowing the refractive index of a material at a certain wavelength could be such a problem. The long solution is to search a book or a paper which helps you to calculate the refractive index, the short solution...
...is going to RefractiveIndex.INFO
created and maintained by Mikhail Polyanskiy. The Database is very extensive and includes:
Crystals/ Metals/ Liquids/ Gases/ Glasses/ Optical Glasses/ Plastics/ Liquid Crystals and even Metamaterials.
Simple choose the material and enter the desired wavelength. But you can do more as only calculating the refractive index. You can choose too from the optical property caculator things like:
reflection coefficient/ Abbe number/ Brewster´s angle/ critical angle or chromatic dispersion.
Simple things, but it save a lot of time. Enjoy!
...is going to RefractiveIndex.INFO
created and maintained by Mikhail Polyanskiy. The Database is very extensive and includes:
Crystals/ Metals/ Liquids/ Gases/ Glasses/ Optical Glasses/ Plastics/ Liquid Crystals and even Metamaterials.
Simple choose the material and enter the desired wavelength. But you can do more as only calculating the refractive index. You can choose too from the optical property caculator things like:
reflection coefficient/ Abbe number/ Brewster´s angle/ critical angle or chromatic dispersion.
Simple things, but it save a lot of time. Enjoy!
Tuesday, December 8, 2009
Modelling an artificial eye with a CCD camera: see how they see!
In September I attended the "IX Reunión Nacional de Óptica" (Spanish National Optics Meeting); one of the posters presented there by the Optics Group from Zaragoza (J. Ares, V. Collados, J. Arines and A. Sánchez-Cano) was "Adiestramiento de la refracción subjetiva con ojos simulados mediante cámaras web". In this communication, the authors reported a system based on a CCD camera to simulate an artificial eye that is used to teach optics and optometry.
Let's start by explaining how the eye works.
Figure 1: Scheme of the eye
In the image an schematic view of an eye is represented; in a very simple model, we can consider the eye as a system formed by a refractive surface, the cornea, and the lens. In a normal eye, the light is focused at the fovea and the image is well-defined. When a person suffers from myopia, light is focused before the fovea; when a person suffers from long-sight, image is formed after the fovea.
Now, how can it be modelled with a web camera? Well, basically the webcam is a CCD sensor with a lens. If we replace this lens by a 35mm focal length lens (typical value for a human eye) and a diaphragm (which will act as a pupil), we can build an artificial eye.
Once, the webcam is ready you can try how people see. Ask for example for a pair of glasses and place them immediately before the webcam. If the person who has lent you the glasses suffers from myopia, you will see a blurred image: this is how this person sees without glasses (or better said, the opposite to the way this person sees: it corresponds to the vision of a long-sighted person with the same gradation):
Figure 2: Pictures from the first row represent a near-sighted eye without (left) and with (right) glasses to correct the myopia. The second row corresponds to a normal eye (ie., the webcam) without (left) and with (right) the same lenses as used in the previous case.
Tuesday, November 17, 2009
Literature Search II: Keep you up in Research – the Virtual Journals and RSS Feeds!
We know how to search relevant papers but science is a very fast developing field, especially the optic communities. To keep up we have to know what is published but we can´t do every week an extensive literature search. The solution is very easy but still satisfying: virtual journals and RSS feeds!
A virtual journal presents an online collection of relevant papers from different journals published during the last week or month. In physics the virtual journals by the American Institute of Physics (AIP) and the American Physical Society (APS) are very good, covering 5 topical areas:
virtual journals
For optics it is called:
virtual journal of ultrafast science
But also the ones for quantum information and nanoscale science contain a lot of optic papers:
virtual journal of quantum information
virtual journal of nanoscale science & technology
The first two mentioned are updated every month, the nanoscale science even every week! But although virtual journals present a good overview about relevant and interesting papers for the community, papers relevant to our work are perhaps (or mostly) not published there. Hence, we have to find an additional way to search relevant papers for us… and RSS feeds will help us a lot.
RSS feeds stands for “Really Simple Syndication” and are placed on many web-pages today. They provide you with the newest articles, information and news on the web-page. You only have to click on the RSS logo and then you can create a folder in the favorite of your browser. Today, more convenient is to connect them directly to your email client or reader. All advanced clients or readers support them (if you don’t have one, search for thunderbird or google reader). Really powerful are RSS feeds if you combine them with word-filters of your email client/reader program! Using the keywords of your research, your email/ reader program collects directly all relevant papers out of hundreds of papers. You don’t have to check them all personally.
Enjoy the lecture ;)!
A virtual journal presents an online collection of relevant papers from different journals published during the last week or month. In physics the virtual journals by the American Institute of Physics (AIP) and the American Physical Society (APS) are very good, covering 5 topical areas:
virtual journals
For optics it is called:
virtual journal of ultrafast science
But also the ones for quantum information and nanoscale science contain a lot of optic papers:
virtual journal of quantum information
virtual journal of nanoscale science & technology
The first two mentioned are updated every month, the nanoscale science even every week! But although virtual journals present a good overview about relevant and interesting papers for the community, papers relevant to our work are perhaps (or mostly) not published there. Hence, we have to find an additional way to search relevant papers for us… and RSS feeds will help us a lot.
RSS feeds stands for “Really Simple Syndication” and are placed on many web-pages today. They provide you with the newest articles, information and news on the web-page. You only have to click on the RSS logo and then you can create a folder in the favorite of your browser. Today, more convenient is to connect them directly to your email client or reader. All advanced clients or readers support them (if you don’t have one, search for thunderbird or google reader). Really powerful are RSS feeds if you combine them with word-filters of your email client/reader program! Using the keywords of your research, your email/ reader program collects directly all relevant papers out of hundreds of papers. You don’t have to check them all personally.
Enjoy the lecture ;)!
Wednesday, November 11, 2009
Very Short Pulses – from Attoseconds to Yoctoseconds!
Coincidentally I noticed a headline:
“Yoctosecond Photon Pulses from Quark-Gluon Plasmas ” [1]
Like many optic scientists I am working with femtosecond laser pulses (1fs=10^-15). Many comrades in my group are dealing with attoseconds (10^-18s). They generate them in high harmonic generation processes and can push them down to around 80as [2,3]! Near to the frontier of the zeptoseconds (10^-21s) scale. In 1as light can travel a distance of 3*10^-10m, which corresponds roughly to the length of three hydrogen atoms. Today, 80as are the limit because of physical reasons in the high harmonic generation process. But new methods are in progress to reach the zeptoseconds scale. Now, a group has proposed a method how to generated yoctoseconds; 1ys is 10^-24 seconds! They describe how high-energetic photon pulses down to the yoctosecond time scale can be produced in heavy-ion collisions, particularly during the formation of a quark-gluon plasma.
How to measure (and to produce them in reality!) and to characterize these yoctosecond pulses… future will know it. However, my comrades have enough to struggle with 80as ;).
[1] Phys. Rev. Lett. 103, 152301 (2009)
[2] Science Vol. 320, 1614
[3] Attoworld
“Yoctosecond Photon Pulses from Quark-Gluon Plasmas ” [1]
Like many optic scientists I am working with femtosecond laser pulses (1fs=10^-15). Many comrades in my group are dealing with attoseconds (10^-18s). They generate them in high harmonic generation processes and can push them down to around 80as [2,3]! Near to the frontier of the zeptoseconds (10^-21s) scale. In 1as light can travel a distance of 3*10^-10m, which corresponds roughly to the length of three hydrogen atoms. Today, 80as are the limit because of physical reasons in the high harmonic generation process. But new methods are in progress to reach the zeptoseconds scale. Now, a group has proposed a method how to generated yoctoseconds; 1ys is 10^-24 seconds! They describe how high-energetic photon pulses down to the yoctosecond time scale can be produced in heavy-ion collisions, particularly during the formation of a quark-gluon plasma.
How to measure (and to produce them in reality!) and to characterize these yoctosecond pulses… future will know it. However, my comrades have enough to struggle with 80as ;).
[1] Phys. Rev. Lett. 103, 152301 (2009)
[2] Science Vol. 320, 1614
[3] Attoworld
Literature Search I: How to find Information concerning your Work!
Very essentially, often underestimated, most poorly done, about what am I talking? Of course of the literature search! The literature search is a very important and powerful tool and helps you to save a lot of time and performing good experiments. Three main purposes are behind a literature search:
1. Find information concerning your experiment achieved by other groups (part I).
2. Keep you up of the progress in your research field (part II).
3. Getting new ideas :) …
In this post I write about the first part, presenting some useful webpages for literature search. The second part follows end of the week (introducing the virtual journals).
Today, nearly all scientific information are online available in the internet. But the challenge is to find it! To do so, many search pages exist which are in parallel checking different databases about your request. Probably your university or institute offers such a search machine too. In science, probably the best search page is:
web of knowledge
The page is well done, user friendly and contains a lot of background information.
Another way (which I really like) is to search directly on the journal homepage. Every (good) journal has today a (advanced) search function. In Optics, most of the relevant articles are published in the journals of the “Optical Society of America” briefly OSA. The link to the journal page is:
Opticsinfobase
You can search on all journals or on specified ones. If you have found an interesting paper, have a look at its references and citings. They are often listed with titles and links to their PDFs. I am sure it contains a lot of interesting papers for you. With time you will notice an author who have several publications on the same field. Check their group homepage! Normally, their full publications list (even PDFs) is online.
An – unusual – approach is to search publications by google. Either by google, or its version for science:
scholar.google.com
It is not as good as the other possibilities, but I had already some nice surprises with scholar google.
Another exotic way but it is worth to mention it, is the:
arxiv server
Papers can there be pre-published before they are accepted or rejected by a journal. Some communities, like the quantum information one, are nearly publishing every article on this server too.
To complete the first part, I want to draw your attention to the:
Encyclopedia of Laser Physics and Technology
It is an open-access encyclopedia with around 570 articles, and it explains the physical principles and common techniques in laser technology.
At the end, please remember that every search machine is worthless if you use the wrong keywords. But with some training you will quickly learn the suitable ones ;).
1. Find information concerning your experiment achieved by other groups (part I).
2. Keep you up of the progress in your research field (part II).
3. Getting new ideas :) …
In this post I write about the first part, presenting some useful webpages for literature search. The second part follows end of the week (introducing the virtual journals).
Today, nearly all scientific information are online available in the internet. But the challenge is to find it! To do so, many search pages exist which are in parallel checking different databases about your request. Probably your university or institute offers such a search machine too. In science, probably the best search page is:
web of knowledge
The page is well done, user friendly and contains a lot of background information.
Another way (which I really like) is to search directly on the journal homepage. Every (good) journal has today a (advanced) search function. In Optics, most of the relevant articles are published in the journals of the “Optical Society of America” briefly OSA. The link to the journal page is:
Opticsinfobase
You can search on all journals or on specified ones. If you have found an interesting paper, have a look at its references and citings. They are often listed with titles and links to their PDFs. I am sure it contains a lot of interesting papers for you. With time you will notice an author who have several publications on the same field. Check their group homepage! Normally, their full publications list (even PDFs) is online.
An – unusual – approach is to search publications by google. Either by google, or its version for science:
scholar.google.com
It is not as good as the other possibilities, but I had already some nice surprises with scholar google.
Another exotic way but it is worth to mention it, is the:
arxiv server
Papers can there be pre-published before they are accepted or rejected by a journal. Some communities, like the quantum information one, are nearly publishing every article on this server too.
To complete the first part, I want to draw your attention to the:
Encyclopedia of Laser Physics and Technology
It is an open-access encyclopedia with around 570 articles, and it explains the physical principles and common techniques in laser technology.
At the end, please remember that every search machine is worthless if you use the wrong keywords. But with some training you will quickly learn the suitable ones ;).
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