
This blog covers all aspects of technology. Cool gadgets, inventions, discoveries, technical tips, interesting facts etc. are to name a few.
Monday, September 15, 2008
Apple iPhone is not worth it!

Monday, August 11, 2008
Sequence Alignment Techniques
Within the nucleus of our cells, a very fine thread like structure is present known as chromosome. The chief component of chromosome is the DNA( Deoxyribonucleic acid). Without getting into much detail, just know this that the DNA can be represented as a string of letters. Example- ACCTGATCGATCAGTGACGAT, such strings are known as DNA sequences.
Let us align 2 DNA sequences. Seq1- ACTG Seq2- ACTP. Without using any algorithms, we can determine the alignment of these 2 sequence.
Suppose the sequences to be compared are much more complex, saySeq1- ABCNYRQCLCRPM( Query Sequence )
Seq2- AYCYNRCKCRBP( Subject Sequence )
In such cases, we use algorithms; 2 main algorithms used are Needleman-Wunsch algorithm and Smith-Waterman algorithm. The former is used for Global Alignment while the latter is used for Local alignment. In Global Alignment the whole of the query seqence is compared to the subject sequence for alignment. In Local Alignment, the query sequence is partioned and , and the bits are compared to the subject sequence. Let us solve the above problem using Needleman-Wunsch algorithm.
3 steps are involved-
=> Initiation of the matrix
=> Filling up the matrix
=> Tracing back
Before we initiate the matrix we have to assign the match value, mismatch value and gap value. Let us keep, match=5 mismatch=-3 gap=-4
=> Filling up the matrix
Then make another similar matrix. In that fill up the same position, with the type of value you have chosen i.e. - whether the diagonal value is selected, the top value is selected or the left value is selected.
Continue filling both the matrix
Figure2- Filled up matrix
Figure3- Filled up Location matrix=>Tracing back
Figure4- Tracing back of the matrix
Based upon the second matrix, we shall trace back. Our start position is the last cell of the last row, and our stopping position should be the first cell of the first row.
After we have obtained the trace back matrix, we shall do the final alignment.
Final Alignment on the basis of first pathway in matrix is:-
Figure5- First pathway in the matrix
If a cell has diagonal arrow, arising from it, then there will be a match. Example- Just consider the brown labeled cell in the above diagram, since it has a diagonal arrow arising from it, P from the left axis and P from the top axis would be a match.
If the cell has vertical arrow arising from it, then there will be a gap along the query sequence. Example- Just consider the green labeled matrix in the above diagram, since it has a vertical arrow arising from it, there would be a gap along the top axis.
If the cell has a horizontal arrow arising from it, then there will be a gap along the subject sequence. Example- Just consider the pink labeled matrix in the above diagram, since it has a horizontal arrow arising from it, there would be a gap along the left axis.
Figure6- Final Result on the basis of the first pathway
Similarly do Final Alignment on the basis of second pathway in matrix:-
Figure7- Second Result on the basis of the first pathwayFigure8- Final Result on the basis of the second pathway
Both these alignments are correct. I hope you have understood this concept, if not feel free to comment and I shall solve your doubts.
Monday, April 21, 2008
How to completely hide your folders!!!!
The trick is simple:-
Step1
Suppose you have a folder named "Max" and the folder is located in C: , the location of that folder would be C:\Max.
Step2
Go to Command prompt. Simply type "cmd" in run(of course without the quotes).
Step3
Type "attrib +s +h C:\Max" (of course without the quotes) and the folder becomes invisible. To make the folder visible again, simply type "attrib -s -h C:\Max".
My humble suggestion is to try this trick on an empty folder initially, in case something goes wrong. Caution- Do not forget the location of the folder, you have made invisible, I suggest that you save the location of the folders, you intend to make invisible. This trick is applicable, not only to folders, but files(all types of files) also.
Sunday, February 17, 2008
C++
Did you understand the meaning of the underlined worlds? Honestly speaking, I did not! I further read and and came out with the following interpretation of the underlined worlds.
- Multi paradigm- C++ language supports both object oriented paradigm and procedural paradigm, hence it is multi paradigm.
- Free form- Initially the computer languages that were formulated , had the code to be written in specific columns. In C++, the code can be written in white space, hence it is free form.
- Compiled- C++ uses a compiler. A compiler, scans the entire code, line by line, and reports errors and warnings if any. A compiler is different from an interpreter. When an Interpreter is used , the errors(most of them) are reported immediately while the code is being written.
- Statically typed- The C++ compiler accepts letters, numbers, characters in a particular type. In statical typing, the typing is done during design time. In dynamic tying the typing is done during run time.
- Data abstraction- In C++ the object ca have many features.Only particular features of the object is written in the code. The particular features are written in the class of the object, and the class is known as data abstraction type.
- Generic Programming- C++ has generic programming features.
- Object Oriented Programming(OOP)- C++ uses objects, to develop applications. These objects interact with one another via various techniques namely Inheritance, Encapsulation, Polymorphism, Modularity.
- Procedural Programming- A procedure can be function, method, routine, sub-routine. In procedural programming, a procedure can be called from any other procedure, without writing the whole code again.
Tuesday, January 22, 2008
Anti matter
Example:- Positron is an electron which has positive charges, an anti proton is a particle which has negative charge.
Significance of anti-matter is that when matter and anti-matter particles collide a lot of energy is released, in accordance to Einstein's equation, E=mc2
where E is Energy, m is rest mass, c is the speed of light.
In matter antimatter reaction, the entire rest mass is converted into energy, hence the reactions are highly efficient. These reactions are more efficient than nuclear fusion reactions, and much more efficient than reactions used in space fuel. The energy is released at the speed of light from the point of annihilation.
If we could master the technology of conducting matter antimatter reactions, all our energy problems would be solved. About 11-12 picograms of antimatter is produced annually most of which is produced in C.E.R.N( European Organization for Nuclear Research). Antimatter particles are the most expensive components priced at an astounding $300 billion per gram.
Sunday, December 30, 2007
Working of a Photocopier

- The drum is shown, it comprises of a coating of selenium. Selenium is a photo conductive material; the property of a photo conductive material is that when light falls upon it, it gets charged. The drum gets charged by high voltage wire. The document to be photocopied is illuminated by light, the white part of the document reflects maximum amount of light, when this light falls on the drum, the negative charged gets diminished by earthing; the written material on the document reflects least amount of light, and corresponding areas of the drum have negative charge. Thus a virtual electrical image is formed on the drum.
- The toner are small particles of ink which are positively charged, they get attached to the negatively charged particles on the selenium.
- The paper which is inserted is attributed a negative charge, which is higher in magnitude as compared to the negative charge on the drum. The toner particles get attached to the paper. The toner is melted and fused in the paper, by a combine action of heat and rolling effect.
- The drum continuously roates during the process of photocopy. Before the next cycle of photocopying begins, the drum is discharged.
Tuesday, December 25, 2007
The Big Toe- world's largest bike

The Big Toe is the world's largest bike. This monster is 2.3m(7.5 feet) high and 5m wide, weighing an astonishing 1645kg.
It has custom designed hydraulic suspension and small supporting wheels to keep it upright. The control panel has the start button and a 5000W speaker with CD player is built within the bike.
It has a top speed of 100km/hr(62mph). It is more of a show bike rather than a street bike. It is not designed to travel at high speeds. It is powered by 1975 Vintage Type E Jaguar SOHC 2 valve 60 degree 300HP 5.3L 12cylinder engine. Intake comes from 45mm twin choke Weber carburetors and a custom stainless muffler system handles the exhaust.
The man responsible for this bike is Tom Wiberg of Sweden. This bike is listed in the Guinness Book of World records as the tallest driveable motorcycle in the world.
Sunday, December 16, 2007
did you know?
- did you know, a fly when alighted on top of a steel bar causes the bar to bend under its weight. the magnitude of bend is extremely small(1/1000 of a centimeter).
- did you know, if a set of fine scales is arranged, so that one scale is kept dark and light is allowed to fall on another scale, the lighted scale will sink slowly. Light has "weight"; the pressure of light on earth's surface is calculated as 2 pounds per square mile.
- did you know, there are very few animals on this planet which are not eaten by something else. One of them is the firefly. The adult firefly with its glowing body has no know predator.
- did you know, every word we speak requires the use of 72 muscles in our body.
- did you know, that a flea accelerates from a standstill to 3 feet per second in less than two thousand of a second subjecting it to a force of 150G. This is roughly equivalent to the force that a driver will experience driving a truck in a brick wall at the speed of 200 miles/hour.
Sunday, October 7, 2007
useful tips
By default, certain amount of your hard disk space is utilized by the recycle bin. In general, it is10%( example- if your hard disk space is 200gb, then the space reserved for recycle bin is 20gb). Now, thats a considerable amount, fortunately the settings of the recycle bin can be changed by clicking on "properties", and the recycle bin can be deemed to hold less space.
Take iPod instead of your laptop when traveling
An iPod (and other portable USB storage devices) can hold computer files, Outlook data, Internet Explorer favorites, desktop wallpaper, and in some cases applications. Connect the iPod to a borrowed PC and it is like having access to your own computer. Later, sync the iPod with your PC back home.
Promote your blog for free
Promote your website of blog for free by making a lens on the Squidoo website. Check out http://www.squidoo.com/ for more information. A Squidoo web presence gives you high rankings on the search engines, particularly Goggle.



