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Saturday, January 14, 2017

The Ellipsis--Hot, Hot, Hot, Dot, Dot, Dots. . . And the Solar Eclipse of August 21, 2017

      This week's Partial Ellipsis of the Sun will focus on the ellipsis in our blog title as well as the upcoming solar eclipse, visible in the U.S. on August 21, 2017. 

     I discovered this week that three dots on clothing labels signifies hot, hot, hot (ok, truly just "hot," but you get the idea)

.  .  .and look at our logo!

      Ellipsis, from the Ancient Greek: ἔλλειψις, élleipsis, "omission" or "falling short") is a series of three dots that usually indicates an intentional omission of a word, sentence, or whole section from a text without altering its original meaning (Look! A typewriter!)

      Depending on their context and placement in a sentence, ellipses can indicate an unfinished thought, a slight pause, an echoing voice, a leading statement, or a nervous or awkward silence. 

     Aposiopesis is the use of an ellipsis to trail off into silence, for example: "I wonder about where to go to view the August 2017 eclipse. . ." When placed at the beginning or end of a sentence, the ellipsis can also inspire a feeling of wonder, sadness, or imagining.

     The most common form of an ellipsis is a row of three periods or full stops (. . .)

or a precomposed triple-dot glyph (…). The triple-dot punctuation mark is also called a suspension point, points of ellipsis, periods of ellipsis, or colloquially, framed as "dot-dot-dot".

     In Anne Toner's book on the ellipsis, Ellipsis in English Literature: Signs of Omission  she suggests that the first use of the punctuation in the English language dates to a 1588 translation of Terence's Andria, by Maurice Kyffin. In that case, however, the ellipsis consists not of dots but of short dashes.

     There are numerous widely acknowledged types of ellipsis. Nine of them are: 1) gapping, 2) stripping, 3) VP-ellipsis, 4) pseudogapping, 5) answer fragments, 6) sluicing, 7) N-ellipsis, 8) comparative deletion, and 9) null complement anaphora. However, rather than getting into further discussion of these nine types of ellipses. . .

let's move on to the solar eclipse of August 21, 2017. 

     The eclipse has its own website. Maizie and I are already planning a camping trip with friends to Wyoming to view the eclipse. How about you? Will your path cross with the solar eclipse. . .?

Only 219 days to go!

Wow! { { { Photograph by Walker Berg, Oregon: CROWS ON SNOW} } }

Tuesday, January 3, 2017

Clutch Problem: Dinosaur Hatchlings Took Too Long to Incubate

     The mystery of why the dinosaurs became extinct after a Cretaceous meteor strike, while birds and mammals thrived, may have been solved.

     Paleontologists have discovered that dinosaur young took so long to hatch and mature into adulthood that populations failed to recover quickly enough after the devastating impact 65 million years ago.

     In contrast, birds and small mammals took only a few weeks for their offspring to emerge giving them a distinct advantage.

     The discovery was made by researchers at Florida State University and the University of Calgary, who realized it was possible to calculate how long it took for dinosaurs to hatch based on marks on the teeth of embryos and babies.

     Similar to tree rings growing a new layer each year, teeth grow a new layer each day, which is seen in microscopic lines in the dentine. By counting the daily lines of Von Ebner, scientists found it took dinosaurs between three and six months to hatch.

     The lengthy incubation period in the clutches of dinosaur eggs, in comparison to small mammals, made the hatchlings, and their parents, vulnerable to predators and left them struggling to re-establish their species.

     “Some of the greatest enigmas about dinosaurs pertain to their embryology; virtually nothing is known,” Dr. Gregory Erickson of FSU said. “We suspect our findings have implications for understanding why dinosaurs went extinct at the end of the Cretaceous period, whereas amphibians, birds, mammals and other reptiles made it through and prospered.” 

     Because birds are in the same clade with dinosaurs, scientists have long assumed that the duration of dinosaur incubation was similar to birds, whose eggs hatch within 11 to 85 days.

     However, similar-sized reptilian eggs typically take twice as long to hatch, ranging from several weeks to many months. To find out where dinosaurs fit in, the team studied the fossils of dinosaur embryos.

     “Time within the egg is a crucial part of development, but this earliest growth stage is poorly known because dinosaur embryos are rare,” said Dr. Darla Zelenitsky of the U of Calgary. “Embryos can potentially tell us how dinosaurs developed and grew very early on in life and if they are more similar to birds or reptiles in these respects.”

     The two types of dinosaur embryos researchers examined were those from a Protoceratops, (seen below) a goat-sized dinosaur found in the Gobi Desert of Mongolia whose eggs were chicken-egg-sized and Hypacrosaurus, a gigantic duck-billed dinosaur found in Alberta, Canada, with eggs weighing 4 kilograms (9 pounds.)

      The researchers ran the embryonic jaws through a CT scanner to visualize the forming dentition. Then, they extracted several of the teeth to examine with a Scanning Electron Microscope (SEM).

     Their results showed nearly three months incubation for the small Protoceratops embryos and six months for the embryos from the giant Hypacrosaurus (below).

       Dental battery (the complex set of six-layered dinosaur teeth including replacement teeth) and von Ebner lines in fossil dinosaur teeth were first observed and illustrated over 150 years ago by Richard Owen (shown below), the scientist who coined the term Dinosauria or "Terrible Lizard."

      I wonder if Dr. Owen would have given his eye teeth to change that moniker to Dinopoulia, Greek for "Terrible Bird."

It's Clutch Time, in more ways than one!

Wednesday, December 28, 2016

Eat, Prey, Swim: Baby Starfish Spin Miniature Whirlpools To Scoop Up Food

      Baby starfish scoop up food by spinning miniature whirlpools. These vortices catch algae and draw them close so the larva can slurp them up, researchers, including Dr. William Gilpin et al from Stanford University report in Nature Physics (12/19/16).

      Before starfish, which are not fish but echinoderms, take on their familiar shape, they freely swim ocean waters as millimeter-sized larvae. 

      To swim around on the hunt for food, the larvae paddle the water with hair-like appendages called cilia. 

     Starfish larvae also adjust the orientation of these cilia to fine-tune their food-grabbing vortices.

      Researchers studied larvae of the bat star (Patiria miniata), a starfish found on the U.S. Pacific coast, 

by observing their activities in seawater suffused with tiny beads that traced the flow of liquid. (Does this remind you a bit of Obi, the parrotlet, and observing the air around him that was suffused with aerosol droplets as he flew?) 

Too many swirls can slow a larva down, the scientists found, so the baby starfish adapts to the task at hand, creating fewer vortices while swimming and whipping up more of them when stopping to feed.

          A video of the  experiment is linked here.

        And I thought we were supposed to wait an hour after eating before swimming. . .

        A post on starfish the week we lost two stars, Carrie Fisher and her mom, Debbie Reynolds? Twin stars/spirits, born of an instant. Rest easy together, ladies.


My artist friend, Judith's, words to Don T. on a clay tablet:


Thursday, December 22, 2016

Western Pacific Biotwang: Whale Noises in Deepest Mariana Trench

     An unusual noise that was recorded near the Mariana Trench could be a never-before-heard whale call.

     Called the "Western Pacific Biotwang," this newly discovered call might be from a minke whale, a type of baleen whale, according to the researchers who documented the vocalization. A baleen whale has plates of whalebone in the mouth for straining plankton from the water. 

      The Mariana Trench stretches 1,500 mi (2500 km) in an arc that is edged by the islands of Guam and Saipan. Its deepest point is known as the Challenger Deep, some 35,756 feet (10,890 m) — or nearly 7 miles (11 km) — beneath the surface of the sea. The trench is deeper than Mount Everest is tall.

     Lasting between 2.5 and 3.5 seconds, the five-part call includes deep moans at frequencies as low as 38 hertz and a metallic finale that pulses as high as 8,000 hertz.

     “It’s very distinct, with all these crazy parts,” said Dr. Sharon Nieukirk, senior faculty research assistant in marine bioacoustics at Oregon State U.“The low-frequency moaning part is typical of baleen whales, and it’s that kind of twangy sound that makes it unique. We don’t find many new baleen whale calls.”

      Recorded via passive acoustic ocean gliders, which are instruments that can travel autonomously for months at a time and dive up to 1,000 meters, the Western Pacific Biotwang most closely resembles the so-called “Star Wars” sound produced by dwarf minke whales on the Great Barrier Reef off the northeast coast of Australia, researchers say.

          This article describes a recording of the new Western Pacific Biotwang. You may hear the 1 minute Biotwang here.

           "We don't really know that much about minke whale distribution at low latitudes," Dr. Nieukirk said. "The species is the smallest of the baleen whales, doesn't spend much time at the surface, has an inconspicuous blow, and often lives in areas where high seas make sighting difficult. But they call frequently, making them good candidates for acoustic studies."

      "The call still needs to be translated. Most baleen whales use specific vocalizations for seasonal breeding and feeding, but this call — since it seems to occur all year — may have a complex function," the researchers said.

Biotwang, Biotwang, Biotwang--what a fun word to say!

Wednesday, December 14, 2016

Thinner Crust: Not Just for Pizza Anymore -- Oceanic Crust has Thinned Since Pangaea Jurassic Time

      Oceanic crust created by the earth today is significantly thinner than crust made 170 million years ago during the time of supercontinent Pangaea, according to U. of Texas, Austin, scientists. The Earth's crust under the oceans is up to 1 mile thinner today than it was during that Pangaean time.

      "The thinning is related to the cooling of earth's interior prompted by the splitting of Pangaea, which broke up into the continents that we have today," said Dr. Harm Van Avendonk, the lead author of the study. The research published in Nature Geosciences on December 12, 2016, illuminates how plate tectonics has influenced the cooling of the Earth's mantle throughout geologic history.

      "What we think is happening is that the supercontinent was like an insulating blanket," Van Avendonk said. "So when these continents started opening up and the deeper mantle was exposed, more or less, to the atmosphere and the ocean it started cooling much faster."

      The mantle is the very hot, but mostly solid, layer of rock between the Earth's crust and core. Magma from the mantle forms oceanic crust when it rises from the mantle to the surface at spreading centers and cools into the rock that forms the very bottom of the seafloor. 

     Since about 2.5 billion years ago, the mantle has been cooling, a phenomenon that does not influence the climate on the surface of the Earth and has nothing to do with the issue of short-term human-made climate change (which is a real phenomenon, DT!). This study suggests that since the breakup of Pangaea, the cooling rate of the mantle has increased from 6 - 11 degrees Celsius per 100 million years to 15 - 20 degrees per 100 million years. Since cooler mantle temperatures generally produce less magma, it is a trend that's making modern day ocean crust thinner. The illustration below of a slice of earth ties in well with the pizza analogy ;-).

      "It's important to note the Earth seems to be cooling a lot faster now than it has been over its lifetime," Dr. Van Avendonk said. "The current state of the Earth, where we have a lot of plate tectonic events, this allows the Earth to cool much more efficiently than it did in the past."

      The research that led to the connection between the splitting of the supercontinent and crust thickness started when Dr. Van Avendock and Ph.D. student Jennifer Harding, a co-author, noticed an unexpected trend when studying existing data from young and old seafloor. They analyzed 234 measurements of crustal thickness from around the world and found that, on a global scale, the oldest ocean crust examined, Jurassic in age, is 1 mile thicker, as noted above. The oldest oceanic crust (or sima, short for silica and magnesium, mainly basalt) is Jurassic in age due to the "recycling" nature of this denser crust versus less dense continental crust (or sial, short for silica and aluminum).

     The link between crust thickness and age prompted two possible explanations, both related to the fact that hotter mantle tends to make more magma. (1) Mantle hot spots, highly volcanic regions, such as the Hawaiian Islands and Iceland, could have thickened the old crust by covering it in layers of lava at a later time. Or, (2) the mantle was hotter in the Jurassic than it is now.

      The analysis ruled out the hot spot theory; thick layers of old crust formed just as easily at distances greater than 600 miles from hotspots, a distance that the researchers judged was outside the influence of the hotspots. In contrast, the analysis supported the hypothesis of mantle cooling after the breakup of the supercontinent.

      The discovery that breaking up Pangaea cooled the mantle is important because it gives a more nuanced view of the mantle temperature that influences tectonics on earth. The researchers also note that the study illustrates the success that can come from spontaneous collaboration and leveraging basic research on a global scale.

Coolly and Warmly,