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Tuesday, May 30, 2017

Track Lighting: Dinosaur "Dance Floor" in Bolivia -- Over 5,500 Footprints

       These late Cretaceous dinosaur footprint fossils on a near-vertical outcrop in Bolivia represent at least 294 different dinosaurs (and, at least 8 species) with over 5,500 footprints.

       The paleontological site, known as Cal Orck'o, is located a few kilometers south of Bolivia's Sucre city center.

       Although, I imagine there was more chasing than dancing on this "Dinosaur Dance Floor," it is an exquisite find, uncovered in 1994, in a cement quarry. Both carnivores and herbivores are represented. This longest set of tracks is over 350 footprints! Parco Cretacio is now open to the public; 68 million years in the making!

     The tracks were likely created by a juvenile Tyrannosaurus rex, nicknamed Johnny Walker ;-).

     And these footprints were likely made by an Iguanodon.

      The extent of dinosaur footprints on over 25,000 square meters is being studied by Christian Myer and Martin Lockley (of Colorado Morrison Dinosaur Ridge footprint fame). The largest prints are 3 feet long.

     Tectonic uplift moved these fossil footprints to a 70 degree plus angle. Pretty wild dance party ;-).

Have you been to see the Bolivian dinosaur footprints? Have you seen dino tracks in the Connecticut River Valley or elsewhere?


{The Colorado Dinosaur Ridge footprints are quite spectacular, but are not nearly as extensive as the Bolivian tracks.}

Saturday, May 20, 2017

Angling Mathematics: Fishing For Complementary Angles

      Our late-spring trip along the North Platte River from Waterton Canyon to Deckers, Colorado, and on to Wellington Lake, was filled with angles and anglers. According to the link cited above, 

  "There are physical properties associated with the bending (refraction of light) which have significant effects on what a trout could possibly see.  The trout’s world consists of a window, the diameter of which is determined by a thing called the Snell’s equation."

    "In simple terms the window is 2.26 times as wide as the trout is deep. So it can clearly see things on the surface over a wider area the deeper the fish is. At one meter the fish can clearly see things on the film in a 2.26 meter wide circle above its head."

      "Many angling writers have made much of this, because a relatively small increase in depth radically changes the size of the window. At 0.5 meters the window has a diameter of 1.13 meters, but at a depth of a meter that window grows enormously to 2.26 meters across. If you take the area of the window the results are all the more dramatic. At 0.5 meters depth the area of the window is 1 square meter, at one meter in depth that window jumps to 4 square meters. Double the depth and you effectively quadruple the size of the window."

      Ah, look at this sky window near Wellington Lake.

       The term angler derives from one who uses an "angle, or, originally "angel," i.e., fishhook for fishing with a line.

     A bit of both angles and angels might be involved in angling mathematics.

       Much better angling earlier in the week than on May 18 during the intense Colorado snowstorm. . .

      Big flakes abound in Colorado this month ;-).

      Are you an angler?

Fishing for complementary angles,

Monday, May 8, 2017

Birdsong and Creativity: Songbirds Name Their Offspring!

      The vocal learning of songbirds is the subject of much ornithological research. Did you know songbirds name their offspring, who are called by that specific sound all their lives? (I wonder if they have middle names, for when they're in trouble. . .)

      Nearly half of bird species are songbirds. They learn songs from a mentor, like humans, and then practice the melodies.

      The baby songbirds learn "grammar and syntax" from these mentors, who are often, but not always, their parents. The songbirds' use of different tweets (the original, non-140-character kind) is more complex than the signals (or typings) of monkeys. 

       According to this bird-brained article, "New neurons grow in breeding and singing season and then die back to save energy. A signal of the dying cells stimulates the new cells."

       "Songbirds prefer singing in harmonic series similar to humans even though anatomically they could sing many other ways. They choose to sing in a particular key and with consonant intervals, octaves, fifths, and fourths like humans. Songs are used for mating and defending territory."

       The study of birdsong is a delicate balancing act. And the study of bird brains (especially songbirds vs. birds like chickens) compared to humans and monkeys is even more complicated.

       Songbirds have more interconnectedness and feedback loops comparable to the parts of the human brain, especially the striatum. Study of songbird chromosomes adds both to the complexity and understanding.

       Zebra finches are useful in understanding how birdsong phrases are learned and how they can be changed and analyzed.

        Of course, you can just listen and enjoy Birdsong, too. This recording was made at daybreak along the Mississippi River near Birdsong, Arkansas, population 41. Temporarily 42. . .

      Be glad and sing out if someone calls you a Songbird Brain! Tweet about it ;-). 

     And this goes right here. . .

"Ah" would be better. . .but close enough.