Microsoft has sued Motorola on patent infringement in their Android mobile phone. Patents involved cover the usual, obvious "inventions", like sync'ing emails from a computer to a mobile phone, the long-filename extension their old FAT file system and others. Microsoft's Corporate Vice President writes in his blogpost:
"Synchronization Technology on Mobile Phones is a patented invention"
Emails and basically all sorts of files have been sync'ed between all computers of the internet for 30 years now ("mirrors" exist as long as computer networks). The idea to synchronize emails and contacts from a computer to a mobile phone must be so totally obvious to anyone with only a very superfluous knowledge of computers that Microsoft should never be able to win this in court.
Unfortunately, judges and lawyers hardly know how to use Microsoft Word and are therefore ready to buy this "we’ve spent over 30 years developing cutting-edge computer software"-nonsense.They really believe that Microsoft has been developing "cutting-edge" computer software. If you have never used a mainframe, never programmed a home computer in the 80s, have no idea of how DOS stole from everyone else, or how Windows 2.11 was just a copy of various parts copied from Apple's Lisa, Xerox Alto, GEM, and others, then you might even believe that syncing emails is a non-obvious "invention". I doubt that this patent has ever been seriously challenged in court (and the same goes for the other eight patents).
All developers of mobile phones infringe many of Microsoft patents. I think it is clear what Motorola should do: first put all of their own trivial software patents into the public domain, then contact other software companies and collect money to get these Microsoft patents invalidated in court, then make a case and lobby members of congress to build more checks and balances into the US patent system. The current way to deal with these patents is just an enormous waste of time and money. It's Microsoft who is currently exploiting it, but very soon it will be another company again. (see also: http://www.guardian.co.uk/technology/2010/oct/04/microsoft-motorola-android-patent-lawsuit)
mercredi 6 octobre 2010
vendredi 18 juin 2010
Determining S-phase length from cell counts (Brdu/Idu)
After a request from a friend, I was recently grappling with the question of how to determine the length of the S-phase of a number of cells. You might know that dyes exist that label cells that are currently in S-phase (Brdu, Idu, radioactive, etc) , but since cells divide all the time and the cells in a dish are usually not syncronized, one can not simply add the label and then wait for the label to go on and off, as the cells have to be killed to make the label visible. You could syncronize all cells to start their cell cycle at the same time and kill some every second to find out when the label comes on, but this is a huge amount of work.
And unnecesary: As it turns out, only two observations are required. Imagine all traffic lights of a town going red and green at different times. There is a technique that allows you to obtain the duration of the green phase from just two aerial images of the whole town, taken at a fixed interval. It took us some time to understand how you can deduce the duration of an event based on just two observations of the whole population.
We came across this in a paper by Martynoga et al and by following the literature, found out that the idea goes back to at least Wimber and Quastler, from the early 60s. It is requires that two different labels are available, let's call them green and red, as they actually are in Martynoga et al (and no, you cannot really do this with traffic lights, as their colors don't stick). The first injection of the dye into the cell population will mark all cells that are currently in S-phase green, the second injection will mark all cells that are in S-phase at the end of the experiment red. Then the cells are killed and the staining is performed.
The first injection is marking cells "green only", the second one red, but the second ones will actually be "red and green": There should be no cells "red only", as the time between the two injections is set short enough that no cell can go into a new cell cycle between the two injections. So we only have "green only" and "red and green" cells and can count them.
What is marked "red/green" is the number of cells that are currently, at the timepoint of the 2nd injection, in the S-phase.
(Although, in Martynoga et al, the labelling agent is present 30 min, they also explain that the dye needs 30 minutes to get into the cells. So the effect of killing the cells after 30 min means that we are pulse-labelling at one single timepoint and only the cells that are in S-phase exactly 30min before killing them will be marked.)
What is marked "green only" is the number of cells that have left the S-phase between the two injection.
(This is marking all cells that exit their S phase during this time, as all cells that exit the cell cycle before it will not be marked at all and all cells that exit the cycle afterwards will be red/green.)
There two basic ideas that just have to be combined to determine the length of S-phase now:
a) At any time, the same number of cells is in S phase. If I have 100 cells, an S-phase of 4 hours and a cell cycle time of 10 hours, there will be always 40 cells in S-phase or more generally, 40% of all cells.
Therefore: Proportion of cells in S-phase = Time of S Phase / Time of cell cycle
PS = Ts / Tc
b) During any duration of time, cells will constantly leave S-phase, the same every hour. If I have 100 cells and a total cell cycle time of 10 hours, 10 cells will leave the S-phase each hour. After four hours, 40 cells will have left S-phase.
Proportion of cells leaving S-phase = Time between injections / Time of cell cycle
PL = Ti / Tc
Dividing one formula by the other gives PS / PL = Ts / Ti. You can resolve this to Ts = PS / PL * Ti
And unnecesary: As it turns out, only two observations are required. Imagine all traffic lights of a town going red and green at different times. There is a technique that allows you to obtain the duration of the green phase from just two aerial images of the whole town, taken at a fixed interval. It took us some time to understand how you can deduce the duration of an event based on just two observations of the whole population.
We came across this in a paper by Martynoga et al and by following the literature, found out that the idea goes back to at least Wimber and Quastler, from the early 60s. It is requires that two different labels are available, let's call them green and red, as they actually are in Martynoga et al (and no, you cannot really do this with traffic lights, as their colors don't stick). The first injection of the dye into the cell population will mark all cells that are currently in S-phase green, the second injection will mark all cells that are in S-phase at the end of the experiment red. Then the cells are killed and the staining is performed.
The first injection is marking cells "green only", the second one red, but the second ones will actually be "red and green": There should be no cells "red only", as the time between the two injections is set short enough that no cell can go into a new cell cycle between the two injections. So we only have "green only" and "red and green" cells and can count them.
What is marked "red/green" is the number of cells that are currently, at the timepoint of the 2nd injection, in the S-phase.
(Although, in Martynoga et al, the labelling agent is present 30 min, they also explain that the dye needs 30 minutes to get into the cells. So the effect of killing the cells after 30 min means that we are pulse-labelling at one single timepoint and only the cells that are in S-phase exactly 30min before killing them will be marked.)
What is marked "green only" is the number of cells that have left the S-phase between the two injection.
(This is marking all cells that exit their S phase during this time, as all cells that exit the cell cycle before it will not be marked at all and all cells that exit the cycle afterwards will be red/green.)
There two basic ideas that just have to be combined to determine the length of S-phase now:
a) At any time, the same number of cells is in S phase. If I have 100 cells, an S-phase of 4 hours and a cell cycle time of 10 hours, there will be always 40 cells in S-phase or more generally, 40% of all cells.
Therefore: Proportion of cells in S-phase = Time of S Phase / Time of cell cycle
PS = Ts / Tc
b) During any duration of time, cells will constantly leave S-phase, the same every hour. If I have 100 cells and a total cell cycle time of 10 hours, 10 cells will leave the S-phase each hour. After four hours, 40 cells will have left S-phase.
Proportion of cells leaving S-phase = Time between injections / Time of cell cycle
PL = Ti / Tc
Dividing one formula by the other gives PS / PL = Ts / Ti. You can resolve this to Ts = PS / PL * Ti
Perhaps this will be helpful for someone one day who stumbles over this with Google.
mardi 6 avril 2010
Medion MD98300 ueberhitzt?
Anleitung zum Öffnen des Laptops und Reparatur von Georg und Max
(this laptop has been only sold in Germany, as far as we know.) Dieser Medion Laptop überhitzt leicht und wird sehr heiss oder zu heiss. Das dürfte oft am Staub innen drin liegen. Wer das Ding gebaut hat, lebt offenbar in einem Land ohne Staub und Aldi war es offenbar egal, dass der Lüfter nach 1-2 Jahren völlig verstopft ist. Im folgenden erklaeren wir, wie man dieses Problem loesen kann, indem man den Laptop zerlegt und den Staub entfernt.
Medion Laptops sind zwar billig (50-100 Euro weniger? Dafür halt null Service, seufz...) aber schwer zu öffnen: Langsam und vorsichtig vorgehen. Eine saubere Unterlage verwenden, nicht hungrig anfangen, genug Licht suchen, stressige Frauen vorher verscheuchen. :-) Ca. 2-3 Stunden Zeit einplanen.
Unbedingt alle Schrauben zusammen aufheben und auf einem Blatt Papier aufschreiben, welche Schraube wo war, sonst kann man gleich eine halbe Stunde mehr einplanen.
Medion Laptops sind zwar billig (50-100 Euro weniger? Dafür halt null Service, seufz...) aber schwer zu öffnen: Langsam und vorsichtig vorgehen. Eine saubere Unterlage verwenden, nicht hungrig anfangen, genug Licht suchen, stressige Frauen vorher verscheuchen. :-) Ca. 2-3 Stunden Zeit einplanen.
Unbedingt alle Schrauben zusammen aufheben und auf einem Blatt Papier aufschreiben, welche Schraube wo war, sonst kann man gleich eine halbe Stunde mehr einplanen.
- Alle Schrauben auf der Unterseite entfernen, Deckel entfernen, Festplatte und Akku, RAM und WLAN karte entfernen
- Das CDROM öffnen mit einer Büroklammer und die beiden Schrauben zwischen Schubladenöffnung und Laptopoberseite entfernen (etwas muehsam).
- Im Batteriefach sind am Ende so graue Plastik-Haken, die kann man öffnen/lösen.
- Die Umhuellung der Scharniere mit einem Schraubenzieher anheben, das schwarze Plastikstück oberhalb der Tastatur mit etwas Kraft Stück für Stück abziehen (Die Tastatur erst einmal an Ort und Stelle belassen, auch wenn sie auf dem Photo bereits entfernt ist)
- Jetzt die Schrauben der Scharniere loesen. Danach kann man das Display flach nach hinten ablegen
- Die Tastatur ist verklebt von unten! Vorsichtig abziehen, darunter sind noch mehr Schrauben.
- Jetzt müsste das Oberteil abzunehmen sein (rechts und links oben sind kleine Haken, die man langsam mit etwas Kraft lösen kann). Alle Kabel die im Weg stehen, mit Hilfe eines kleinen Schraubenziehers in ihren Steckern lösen (sind oft so kleine Arretierungen drumherum, die man erst leicht rausziehen muss) und dann abnehmen. Die beiden Displaykabel kann man nicht abnehmen, die sind aber lang genug sofern man das Display hinten liegen lässt.
- Jetzt das CDROM Laufwerk komplett entfernen (rausziehen) und auf der linken Seite die verschiedenen Anschlüsse (USB, firewire, SVideo) aus dem Plastikgehäuse rauswürgen (Kraft notwendig und ein Schraubenzieher, das Gehäuse muss dafür ordentlich verbogen werden)
- Jetzt kann man die Platine rausnehmen, Plastikkabel nach Gusto dabei aus den Steckern ziehen, ausser dem Bildschirm, dessen Stecker ist geklebt, stoert aber nicht.
- Auf der Unterseite der Platine links oben ist der Kühler jetzt zugänglich. Alle Schrauben um den Prozessor vorsichtig lösen (das knakst etwas wegen der Federn um den Prozessor herum), den Kühler abnehmen und die Schrauben um den Lüfter herum entfernen.
- So sieht ein Aldi Lüfter aus nach zwei Jahren in einem Wohnzimmer:
- Staub entfernen, alles wieder zusammenbauen und drauf hoffen, dass der Computer noch geht.
- Viel Glueck! Und wenn es geklappt hat, freuen wir uns über einen kleinen Kommentar unten (es blieben 7 Schrauben übrig, wer weniger schafft: herzlichen Glückwunsch. Funktionieren tut er aber trotzdem.)
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