Bifurcation

A natural connective overlapping of two adjacent watershed areas is called bifurcation, and a bifurcation lake is one that unites two such watersheds in a natural way.

Such overlapping connection occurs, where the water parting divide is not markedly determinative and therefore waters may run off in both shed directions. Bifurcation lakes are, among others, the Lumenne and the water divide at Padasjoki, which both belong to the watershed area of Kokemäenjoki on the one hand, and to that of another river, Kokemäenjoki, on the other.

Such a lake may even divide the water of a river descending from a certain watershed system into two, in other terms, there is one river which descends to the lake, and there are two rivers starting from it, running in different directions. The most well-known bifurcation lakes of Finland are Inhottujärvi and Isojärvi within the water drainage basin of the river Karvianjoki in Northern Satakunta.

The watershed areas of Karvianjoki include three rivers which run to the sea: of the two draining riverbeds which start from Inhottujärvi the first one runs to the sea. The other river flows into Isojärvi, from where two different rivers run on to the sea.

The lake was dammed to serve the Lesja Iron Works in the 1660s and now has two outlets. It flows both East into the Gudbrandsdalslågen and west into the Rauma river in the magnificent Romsdalen valley.

Further 'research' on my behalf has led me to having a close look at maps of Norway. If I'm reading the maps correctly then there are numerous 'splitting rivers' as well as a few lakes with at least two outlets. I'm having a bit of trouble confirming some of the names with Google Maps and finding the right lake, but apparently one exists that has two rivers exiting it. One leads to the atlantic and the other to the sea near Sweden. Basically splits the country. I think the main thing required is lots of glacial action throughout the region/world's history.

Perhaps you found Lesjaskogsvatnet (http://en.wikipedia.org/wiki/Lesjaskogsvatnet) - quoting Wikipedia: "The lake was dammed to serve the Lesja Iron Works in the 1660s and now has two outlets." This is an artificial situation.

You can get multiple outlets if its a temporary measure like damming or if there is a sudden rainfall causing temporary flooding. You can get it to some extent with glacial action but it would have to be pretty active or perhaps seasonal whereby, for example, one river is dammed through being iced up for only parts of the year. Otherwise, in general and in the longer term, one river will always win since its an obvious note that you had two rivers with good carrying capacity and it was steady flow then the water in the lake would fall to the lowest. Where they are equal, one would silt up before the other and then the winner takes both flows thus increasing the erosion on that flow and causing sediment build up on the other. So a man made or changing environment I could believe but I don't think it can happen in a steady state long term deal.

it is the largest lake in the world that drains naturally in two directions.[4] The Fond du Lac River flows out of the lake to the northwest, where it drains into Lake Athabasca, which ultimately drains into the Arctic Ocean via the Mackenzie River system. The Cochrane River flows out of the northeastern side of the lake and into Reindeer Lake, which drains via the Churchill River system into Hudson Bay.

In the mid 18th century, the outflow of Lake Walen was where two rivers, the Linth and the Maag, connected. Spring snow melts caused flooding at the juncture of the two rivers, raising water levels on Lake Walen and creating swampland along the shoreline.

Lake Baikal: The Soul of Siberia

Join Wellesley College's Russian and Biology departments for Lake Baikal: The Soul of Siberia, a Spring-semester course designed to acquaint students with both the scientific and cultural issues surrounding Lake Baikal and the Baikal region. Students will study the ecology of Lake Baikal and Siberia, the Russian environmental movement, and the singular cultural values of a lake that is not only the most biotically rich in the world but is also the "soul of Siberia." Coursework at Wellesley in the spring will be supplemented by travel to eastern Siberia in August 2011. This is the first Wellesley course to unite a Science department and a Humanities department.

Marianne Moore

Mathematical Physics I

Announcements:

Notes on the Hamiltonian & particle interpretation of the 2d scalar field theory are up.
This is a class on quantum field theory, emphasizing Euclidean path integrals and the relation to statistical physics.

Syllabus

TuTh 11:20am-12:40pm in Chemistry 124

Instructor: A.J. Tolland

A (personal) blog of data sketches from the New York Times Graphics Department. Maintained by @KevinQ.

Einstein's Demands

First Digital Message Sent Using Neutrinos
Physicists commandeer a beam of neutrinos to send a message through solid rock but at a painfully slow data rate

A group of scientists led by researchers from the University of Rochester and North Carolina State University have for the first time sent a message using a beam of neutrinos – nearly massless particles that travel at almost the speed of light. The message was sent through 240 meters of stone and said simply, "Neutrino."

M. Wang says:
May 2, 2012 at 3:54 am
Two years ago, when a new firm raised $300m to dig a STRAIGHT-line trench for a new fibre optics line between Chicago and New York, I had joked with a colleague that the next step would be neutrino beams, which was the only thing capable of avoiding the earth’s curvature. I guess someone else has now come up with the same idea, but not as a joke.
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The reason why these investment makes sense (to varying degrees) is the physical separation of trading activities in two sets of financial assets: stocks and the stock-index-based futures. The former trades in New York, but the latter trades in Chicago. Usually, the big pension funds or mutual funds find it cheaper to enter/exit a big position by buying/selling futures than the corresponding stocks. Therefore, the futures price would move first. The competition to use this information to make money on the slower stock markets is intense. The aforementioned new fibre line saves 2ms in communication time, for which the firm charges $1m per month. Only the leading arbitrageurs in the country, typically with $500m or more in annual revenue can justify the expense.
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It is important to stop this senseless race of shaving off another nano-second; there is no increased productivity once the refresh lag drops below human reaction time, roughly 200ms, a milestone that was passed in 2004. On the contrary, there is actually tremendous downside in this crazy speed race, as witnessed two years ago in the “flash crash”. Actually, there are plenty of simple and natural remedies, such as charging for rapid cancellations of orders on the book for less time than human can react to, but the US equity market is “self-regulated”, i.e. the SEC does not set the detailed rules; the exchanges do. The root cause to all this silliness can therefore be traced to the fragmentation of the equity (i.e. stocks) markets in the US. As each of the four major exchanges compete for order flows, they become beholden to the largest traders, and nobody can do more volumes than high-frequency firms.
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Finally, just two weeks, the NASDAQ (in my opinion, the most professional and sensible exchange in the US) decided to take a small step in the right direction. A small fee will be charged on frivolous order placements/cancellations. So, maybe speed will lose its allure and no one will be funding the neutrino idea…

Two years ago a hotshot trader approached James Barksdale looking for money for a rather quixotic venture: to dig, from scratch, a superfast fiber-cable route for sending trades between Chicago and New York. It would be nearly as straight as the crow flies and create a new critical link for speed-obsessed traders. Barksdale, now 67, was familiar with high-concept ideas from his days as chief executive of Internet browser Netscape and at&t Wireless. But this was a bit much.

Wittgenstein and ant-watching
Deborah M. Gordon

REAR WINDOW loop (2011)

a visual installation by Jeff Desom

based on footage from Alfred Hitchcock's "Rear Window" (1954)

I dissected all of Hitchcock's Rear Window and stiched it back together in After Effects. I stabilized all the shots with camera movement in them. Since everything was filmed from pretty much the same angle I was able to match them into a single panoramic view of the entire backyard without any greater distortions. The order of events stays true to the movie's plot.

Tiling

An application of the Theorema Egregium is seen in a common pizza-eating strategy: A slice of pizza can be seen as a surface with constant Gaussian curvature 0. Gently bending a slice must then roughly maintain this curvature (assuming the bend is roughly a local isometry). If one bends a slice horizontally along a radius, non-zero principal curvatures are created along the bend, dictating that the other principal curvature at these points must be zero. This creates rigidity in the direction perpendicular to the fold, an attribute desirable when eating pizza, as it holds its shape long enough to be consumed without a mess.

MTR509 - Spectral Theory of PDE's

Prof. Ari Laptev

 

Course information

The goal of this course is to give an introduction to a number of new results in Spectral Theory obtained during the last decade

On the geometry of tangent bundles

Readings from quant-ph

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Matthew J. Donald

The Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, Great Britain.

e-mail: mjd1014@cam.ac.uk