Format currency in Indian System in Excel

Problem: The Indian system uses a comma separation convention which is different from the typical Western convention

e.g. Rupees 10 million (10,000,000) is conventionally written as Rs. 1,00,00,000

Why? Because it is read as Rs. One crore.

Excel formatting options:

Right click, choose custom formatting, enter the following in the formula

For Rupees with Paise--

[>9999999]"Rs. "##\,##\,##\,##0.00;[>99999]"Rs. "##\,##\,##0.00;"Rs. "##,##0.00

For Rupees without Paise ---

[>9999999]"Rs. "##\,##\,##\,##0;[>99999]"Rs."##\,##\,##0;"Rs. "##,##0

Source: http://www.tech-archive.net/Archive/Excel/microsoft.public.excel.misc/2006-01/msg02617.html

Neurons

Useful Links

1. http://neurocomputing.org/

2. Illustration of neural activity ( Source:http://www.bioedonline.org/resources/files/4_BLCh_MessageInNeuron.pdf )

3. Neurons and smell

Text copied directly from:

http://www.sciencedaily.com/releases/2006/11/ 061108112001.htm

Odor Discrimination Linked To Timing At Which Neurons Fire

ScienceDaily (Nov. 8, 2006) — Timing is everything. For a mouse trying to discriminate between the scent of a tasty treat and the scent of the neighborhood cat, timing could mean life or death. In a striking discovery, Carnegie Mellon University scientists have linked the timing of inhibitory neuron activity to the generation of odor-specific patterns in the brain's olfactory bulb, the area of the brain responsible for distinguishing odors.

Their work, appearing in the Nov. 8 issue of the Journal of Neuroscience, describes for the first time a cellular mechanism linking a specific stimulus to the timing at which inhibitory neurons fire. This breakthrough lays a cellular foundation for the "temporal coding hypothesis," which proposes that odor identity is encoded by the timing of neuronal firing and not the rate at which neurons fire.

Past research has shown that specific odors trigger unique patterns of electrical activity in the brain. Generating these patterns requires reliably timed inhibition, but relatively little was known about the timing of the activity of inhibitory neurons -- until now.

"There is a clear link between which odor is being presented and the time at which inhibitory neurons fire. This timing controls which excitatory neurons are active and at which time. This modulation contributes to the generation of reliable temporal patterns of neuronal activity," said Nathan Urban, an assistant professor of biological sciences at the Mellon College of Science at Carnegie Mellon.

Populations of mitral cells, a type of excitatory neuron in the olfactory bulb, receive input from neurons in the nose that respond to a single odorant. After receiving this input, the mitral cells convey messages about odor identity to other parts of the brain. But they don't simply relay information. Their activity, and therefore which message they send, is modulated by the inhibitory activity of granule cells. In a first, Urban has shown that the timing of granule cell firing encodes odor information.

Urban's work is especially provocative given that the traditional view holds that the rate of neuronal firing is what really matters, not the time that it takes for a stimulated neuron to fire. Recognition of a stimulus like an odor relies on the orchestrated firing of neurons, both ones that excite other neurons to relay a message as well as ones that inhibit or alter how a message is relayed.

"Our results indicate that the latency period before a single granule cell fires is associated with a specific odor, thus linking the timing of inhibitory modulation of mitral cell activity to odor identity. In other words, the timing of granule cell firing conveys different messages. In this case, the messages relay which odor is present," explained Urban.

Urban monitored the subtle-yet-coordinated activity of populations of granule cells in living brain slices using calcium imaging, an optical imaging technique that has never been applied to studies of the olfactory system. Urban loaded the neurons with a fluorescent dye that emits a yellow glow. This glow decreases when the dye binds to calcium. Because the flow of calcium ions into and out of cells corresponds to their firing, Urban was able to actually watch which neurons were firing and when.

Urban stimulated mitral cells, which in turn stimulated granule cells. He found that granule cells respond by firing over a range of times, from a fraction of a millisecond to hundreds of milliseconds. But, according to Urban, the most striking observation was that specific granule cells reliably fired with the same latency when they receive input from certain populations of mitral cells. Input from one group of mitral cells (hence, one set of odor receptors) caused certain granule cells to fire with a 500-millisecond delay, for example. Input from another set of mitral cells (a different set of odor receptors) caused the same granule cells to fire with a 50-millisecond delay. Thus, he found that the timing of granule cell firing is directly related to the input the mitral cells receive -- the original odorant.

"This is the first time we have seen reliable timing of firing. It turns out that cells are better at clocking their firing than previously thought," Urban said.

"This finding is a springboard to addressing other important questions," Urban added. "For example, what are the molecular mechanisms by which granule cells time their firing? We are now exploring this question, as well as how we can observe this odor-specific timing in living animals."

The research is supported by the National Institute of Deafness and Communication Disorders.

Charlie Munger

1. Someone's notes on Munger's mental models - http://www.focusinvestor.com/FocusSeriesPart3.pdf

Mobile in India

1. Subscribers: 100 million rural, 280 million urban.

2. Upcoming 3G will primarily help voice as the spectrum is clogged. Data will be secondary.

3. Ajit Balakrishnan of rediff thinks

• India has 40 million unique Internet users over a month. In 10 years - he expects the number to be 300 million.
• India has 300+ million mobile phone users; estimates of how many of these access the internet in any given 30 day period vary but 10m looks right
• Lack of credit cards has caused ecommerce to be nascent in India. He thinks debit cards may be a solution.
• India needs angels and VC's. Can't rely on US investors.
• For VAS, Indian operators tend to keep over 80%. Says it should be near 50%. In China, they keep only 25%
• Print has a reach of 200M. TV has a reach of 200M. So Internet is ~20% of those two but gets only 3% of total ad revenues. Three reasons - poor broadband penetration, lack of localization, poor credit card penetration (India has 10M credit card users only because India lacks a credit rating system).
• Interesting analogy - With 3G, India may leapfrog PC's and go straight to mobiles as India bypassed mainframes.

4. Leading cell phone brands in India, Apr 2009. GSM-CDMA = 70:30

Brands	Installed base*
	GSM	CDMA	Total (GSM + CDMA)
LG	4.4%	47.6%	14.4%
Motorola	7.8%	5.4%	7.2%
Nokia	62.6%	24.3%	53.7%
Samsung	9.0%	11.2%	9.5%
Sony-Ericsson	8.9%		6.8%

5. SMS in India - http://www.slideshare.net/cellzapp/mobile-market-report-sms-usage-in-urban-india

• Men use SMS for sports, stocks; Women use it for astrology and spirituality
• 20% of mobile users use SMS
• 30 % SMS services used in 6 largest metros
• 25% participated in some content through SMS
• Topics of interest on SMS - jokes, astrology, news and jobs
• 10% mobile users use SMS for social networking

In progress...

Comic Book Industry in India

1. Introduces the comic book culture in India http://www.accu.or.jp/appreb/09/pdf34-1/34-1P006-007.pdf

2. Character licensing in India

"total character licensing sales in India are estimated at Rs.500 crore."

http://www.webnewswire.com/node/449418

3. Recent NY Times article on Indian comics -

http://www.nytimes.com/2009/07/20/business/global/20comics.html

In progress...

Google Q2 09 Earnings

Excerpts from Google's Q2 2009 earnings

Strategic growth areas - display [?], mobile and apps.

Revenue: ~ 5.5B USD

Domestic vs. International revenue: ~ 50-50 (for last 6 quarters)

For $100 of advertising revenue, Google's approximate acquisition cost ~ $27 ( decreasing slowly, from $29 1 year ago).

GAAP Operating margin: ~ 35%

Free Cash Flow: Fairly consistent over the last 3 quarters Q2,09: 1.4B

(Good article on FCF: http://www.investopedia.com/articles/stocks/07/easycashflow.asp?partner=answers)

Marc Andreessen and Horowitz 300M fund

Today Marc Andreessen and Ben Horowitz announced their $300M Venture fund. Interesting to note that they are focused on IT and Computer Science, unlike some others.

Areas of focus:

1. Consumer Internet
2. Business Internet (SaaS, cloud)
3. Mobile software and services
4. Software powered consumer electronics
5. Infrastructure and applications software
6. Networking, storage, databases, backend systems

http://blog.pmarca.com/2009/07/introducing-our-new-venture-capital-firm-andreessen-horowitz.html

Volume of a cone = 1/3 Cylinder; Proof without calculus

Why is the volume of a cone 1/3 of a cylinder? Here's my way of proving it based on geometry without using calculus.