Fish swimming in schools, new research


This August 2017 video says about itself:

Shimmering schools of fish have dazzled scientists for centuries with their synchronized maneuvers. Now, high-speed video is revealing how—and why—they do it.

From New York University in the USA:

Best ‘classroom’ shapes for fish swimming in schools

November 4, 2019

A team of researchers has identified the best arrangements for fish swimming in schools — formations that are superior in terms of saving energy while also optimizing speed. Its findings, which appear in the journal Physical Review X, point to potential new ways to enhance energy-producing technologies.

The work, conducted by researchers at New York University’s Courant Institute of Mathematical Sciences, also confirms a long-held belief: fish swimming in orderly groups or formations spend less energy and move faster than when swimming alone.

“Animals have figured out some interesting tricks that can save energy and move faster, and these behaviors could translate into new energy-harvesting and propulsion devices,” says Leif Ristroph, an associate professor at the Courant Institute and one of the paper’s co-authors. “Our model could inform how to optimize such technologies.”

Using a new type of mathematical model, the team, which also included Michael Shelley, a professor at the Courant Institute, and Anand Oza, an assistant professor at the New Jersey Institute of Technology, focused on several arrangements of swimmers to see which were the best in terms of saving the energy required to swim and enhancing the speed of swimming for the group. In particular, using computer simulations, they examined how multiple flapping swimmers emit vortices, or swirling flows, and also interact with the vortex flows produced by others in the school.

In every school formation tested, the group of swimmers used less energy and moved faster than did solitary swimmers, with some notable differences among these arrangements:

  • Phalanx arrangements, in which fish are lined up side-by-side, showed modest improvements over a solitary swimmer;
  • Tandem formations, in which fish are lined up single file one after another, showed even more improvement over a solitary swimmer;
  • Rectangular lattice formations — which combine the phalanx and tandem formations so that each fish has neighbors directly upstream, downstream and to either side — were superior to both the tandem and phalanx schools;
  • Diamond-shaped lattices, in which each fish has one direct upstream neighbor as well as two neighbors upstream and somewhat displaced to each side, yielded the greatest speeds and largest energy savings — i.e., the best formation tested.

The researchers note that both the phalanx and diamond-lattice formations have been observed in fish schools, with smaller schools tending to adopt a phalanx formation and larger schools choosing a diamond lattice.

“By formulating a mathematical model capable of handling many swimmers interacting through their collectively generated flows, we think we have offered some concrete support for the idea that schooling fish may benefit from flow interactions,” observes Ristroph. “We also hope to apply these same methods to other related problems — for example, flying formations of birds.”

Spot-crowned barbets in Panama, video


This video says about itself:

Spot-crowned Barbets Return To The Feeder – Nov 2, 2019

We haven’t seen Spot-crowned Barbets at the feeder since Spring. They breed during the wet season in Panama which occurs from May through December and are absent from the feeder for much of that time. Females have a mostly black head, neck and throat and males have yellow and white patterned throats and underparts.

Prehistoric Floridans ate sea turtles, new research


This March 2019 video from the USA says about itself:

Florida beaches are some of the highest density nesting sites for loggerhead turtles in the world. As such, they’re a major focus for conservationists looking out for this endangered species.

From the Florida Museum of Natural History in the USA:

Ancient bone protein reveals which turtles were on the menu in Florida, Caribbean

November 4, 2019

Thousands of years ago, the inhabitants of modern-day Florida and the Caribbean feasted on sea turtles, leaving behind bones that tell tales of ancient diets and the ocean’s past.

An international team of scientists used cutting-edge technology to analyze proteins from these bones to help identify which turtle species people fished from the ocean millennia ago. This can aid modern conservation efforts by helping construct historical baselines for turtle populations, many of which are now endangered, and illuminate long-term trends of human impacts.

The technique, known as collagen fingerprinting, allows scientists to visualize distinct chemical signatures in collagen, the main structural protein in bone, that are often species-specific. This provides a complementary alternative to comparing specimens’ physical characteristics and analyzing ancient DNA, two methods that can be unsuccessful for species identification in fragmented archaeological bones found in the tropics.

Applying collagen fingerprinting to more than 100 turtle samples from archaeological sites up to 2,500 years old, the researchers found that 63% of the collagen-containing bones belonged to green turtles, Chelonia mydas, with smaller numbers of hawksbill turtles, Eretmochelys imbricata, and ridley turtles, Lepidochelys species. Some specimens previously identified as sea turtles from their skeletal features were in fact bones from snapping turtles, terrapins and tortoises.

“This is the first time anyone has obtained species-level information using proteins preserved in archaeological sea turtle bone,” said Virginia Harvey, the study’s lead author and a doctoral researcher in marine biology and zooarchaeology at the University of Manchester. “Our method has allowed us to unlock ancient data otherwise lost in time to see which species of turtle humans were targeting thousands of years ago in the Caribbean and Florida regions.”

Globally, sea turtles have been exploited for millennia for their meat, eggs, shells and other products. Today, they face threats from habitat loss and disturbance, poaching, pollution, climate change and fisheries. Only seven species of sea turtle remain, six of which are classified as vulnerable, endangered or critically endangered. Gaining a historical perspective on how turtle populations have changed through time is a crucial component of conserving them, Harvey said.

One of the research team’s initial goals was to discern whether any collagen still survived in ancient turtle bone remains. In an analysis of 130 archaeological turtle samples, the team was able to detect collagen in 88%.

“We were very impressed with the levels of protein preservation in the turtle bones, some of which are thought to be up to 2,500 years old,” said study co-author Michelle LeFebvre, assistant curator of South Florida archaeology and ethnography at the Florida Museum of Natural History. “The fact we were then able to use the protein signatures for species identification to better understand these archaeological sites was very exciting.” …

Using collagen fingerprinting to correct misidentifications based on physical characteristics was “a nice additional outcome of the study,” said Michael Buckley, senior author of the study and senior research fellow at the University of Manchester.

Susan deFrance, study co-author and professor in the University of Florida department of anthropology, said juvenile sea turtles are often misidentified because they are small and may lack the characteristics used to distinguish adult sea turtle bones.

“This is the first time we have been able to look so specifically into the preferred food choices of the site occupants,” she said. “At the Florida Gulf Coast site, they captured a lot of juvenile turtles. The positive species-level identifications of these samples could not have been accomplished without this collagen fingerprinting technology.”

At the same site, researchers found green turtle remains in both refuse heaps and mounds, but ridley turtle specimens were only found in mounds, suggesting they may have been reserved for feasting rituals, LeFebvre said.

“We knew these ancient people were eating sea turtles, but now we can begin to hone in on which turtles they were eating at particular times,” she said. “It’s no different than today — we associate certain foods with certain events. It’s how humans roll.”

The researchers are also eager to continue to apply collagen fingerprinting to other archaeological museum specimens, many of which have yet to be positively identified to the species level.

Harvey said she hopes the study inspires further research on sea turtles and other vulnerable and endangered animals.

“Now that this method is available, we hope that biologists, archaeologists and conservationists globally will continue this important work.”

Casper Toftgaard of the University of Copenhagen and Andrew Kitchener of National Museums Scotland, Edinburgh also co-authored the study.

Neo-nazi synagogue bombing plot, Colorado, USA


This 4 November 2019 video from Colorado, USA says about itself:

Richard Holzer Arrested In Plot To Blow Up Pueblo’s Temple Emanuel [synagogue]

Translated from Dutch NOS TV today:

In the United States a man was arrested who wanted to commit an attack on a synagogue. The 27-year-old man from the state of Colorado is said to have planned a bomb attack on the Temple Emanuel Synagogue in Pueblo city, south of Denver. Court documents show that he wanted to unleash a “racial holy war”.

Richard Holzer was arrested last weekend after he accepted 14 dynamite sticks and two pipe bombs from some men and women about whom he thought they supported him. That turned out to be undercover FBI agents and the explosives turned out to be fake. He is said to have intended to commit the attack that day.

According to the FBI, Holzer told the agents that he is a skinhead and that he used to be a member of the Ku Klux Klan. He is said to have glorified violence on Facebook and spread messages in which he recommended white supremacy.

Mein Kampf

He is also said to have been very anti-Semitic on several occasions in his contact with the undercover agents. When he met one of them, he was “wearing a Nazi armband” according to the FBI. He is also said to have had the book Mein Kampf [by Adolf Hitler] with him.

See also here.

White Supremacist Arrested For Plot To Blow Up Colorado Synagogue … Holzer also used racial slurs to refer to Latino people: here.

A group of men wearing large white kippas and tallesim handed out fliers promoting Holocaust denial and hung up cards bearing anti-Semitic canards on a pedestrian mall in Boulder, Colorado. The fliers handed out at Boulder’s Pearl Street Mall by the men who appeared to be posing as Jews claimed the Holocaust was “impossible”. The men also hung notes on index cards around the mall that claimed “Academia is dominated by Marxist Jews”, Jews run the porn industry,” and “Jews ran the Atlantic slave trade,” the Daily Camera newspaper reported: here.

In addition to Holzer, at least 12 other people have been arrested for participating in plots to attack Jews since the Tree of Life shooting, according to the Anti-Defamation League. The ADL reports that incidents targeting Jews surged 57 percent in 2017. In the first half of this year, the ADL recorded 780 anti-Semitic episodes across the US: here.

Richard Holzer (Facebook)

This Week Proves It: Anti-Semitism On The Right Is The Only Real Threat To Jews: here.