Hobby nest in Leiden, the Netherlands


This video from the Netherlands says about itself:

22 May 2015

Hobby falcons hunting for large insects, picking them out of the sky with their talons and eating them flying in slow-motion.
Falco subbuteo.

Arthur Staal from the Netherlands writes on his blog about hobbies nesting in Leiden city.

There is at least one youngster on the nest, as a photo shows.

Hobbies are rare as breeding birds in the Netherlands. In Leiden, they used to nest in poplar trees along a road. After these trees were cut down, local authorities provided a new nest in another tree, near Naturalis museum. Fortunately, that worked.

See also here.

Most painful plant arrives at botanical garden


This video says about itself:

Most Painful Plant

31 January 2015

The gympie gympie plant has an excruciatingly painful sting. It’s one of the most venomous plants in the world.

Its sting is infamously agonizing. An officer once killed himself in order to escape the pain. It’s from the gympie gympie plant, and here’s what you need to know to survive.

What is it?

The gympie gympie plant, or Dendrocnide moroides, is one of the world’s most venomous plants with large, heart-shaped leaves. It’s known as a stinging because because of its stinging hairs that deliver a potent neurotoxin when its leaf is touched. The pain from a sting has been described as unbearable, driving its victims to the point of madness. Stories have been told of horses jumping off cliffs after being stung just to escape the pain. It was extensive[ly] studied for years by Dr. Marina Hurley.

Where is it located?

Gympie gympies are native to the rainforest areas of northeastern Australia, the Maluku Islands (Moluccas), and Indonesia. They’re large shrubs with bright pink fruits whose seeds germinate and flower in full sunlight after soil disturbances.

How will it kill you?

The entire gympie gympie plant is covered in fine, silicon-like hairs that embed themselves in your body after which they release a painful toxin. Breathing them in can cause severe sneezing fits and nosebleeds. Stings start out as a painful burning sensations that grow more and more intense over the next half hour. It can then lead to aching joints and swelling under your armpits as well as vomiting due to the intensity of the pain. The pain can last from a few days up to several months. Also, it can become so severe that it can eventually lead to shock followed by death.

How to survive:

Gympie gympie stings are felt immediately and its hairs must be removed right away in order for the pain to subside. The recommended treatment is to apply diluted hydrochloric acid onto the affected skin areas then pulling the hairs out with a wax hair removal strip. If you don’t remove all the gympie gympie hairs, they can keep releasing their toxin into your skin for up to a year.

The Leiden botanical garden reports that this week, a gympie gympie plant has been added to their collection; not to the part of the collection open to the public, because of the danger of the sting.

The gympie gympie plant is related to stinging nettles; however, its sting is about a hundred times worse.

Comet Halley, new research


This video says about itself:

Giotto: Halley’s Comet Flyby Animation (1986.03.14)

1 October 2011

On March 13, 1986, ESA’s Giotto probe swept within 600 km of Comet Halley, obtaining the first close-up images of a comet. It revealed the first evidence of organic material in a comet and, still today, much of what we know about comets comes from the pioneering mission.

Launched on July 2, 1985 by Ariane 1, Giotto was ESA’s first deep-space mission, part of an ambitious international effort to solve the mysteries surrounding Comet Halley. It was also the first deep-space mission to change orbit by returning to Earth from an interplanetary trajectory for a gravity-assist.

After a cruise of eight months, Giotto arrived at its destination and revealed the size and shape of Halley’s nucleus, found that its surface is very dark (the blackest object in the Solar System) and that it emitted jets of gas and dust.

Giotto’s camera recorded many images that gave scientists a rare opportunity — the comet will not return to the inner Solar System again until 2061 — to study Halley intensively. It was particularly important to determine its composition through the readings made by Giotto as it passed through Halley’s tail.

After completing its Halley mission, Giotto went into hibernation before being woken up in the summer of 1990, and then hibernating again until early 1992.

Although a few of the instruments had been damaged during the Halley encounter, the spacecraft had survived the battering by cometary dust and was able to conduct a second flyby, this time of Comet 26P/Grigg-Skjellerup, in July 1992.

This video is a new compilation of Giotto’s historic images acquired by the Halley Multicolour Camera (HMC). It shows the comet as seen by the probe as it approached from about 900,000 km, coming to within 596 km.

The images were processed by the HMC team under the leadership of Uwe Keller at the Max Planck Institute for Solar System Research (MPS/Lindau), where this video was newly produced in 2011 together with B. Grieger from the Rosetta team at ESA/ESAC to mark the 25th anniversary of Giotto’s flyby.

credit: Max Planck Institute for Solar System Research

From Leiden University in the Netherlands:

Chaotic orbit of Comet Halley explained

Published on 30 June 2016

A team of Dutch and Scottish researchers led by Simon Portegies Zwart (Leiden University) has found an explanation for the chaotic behavior of the orbit of Halley’s Comet. The findings are accepted for publication in the Monthly Notices of the Royal Astronomical Society.

Halley’s Comet is one of the most famous comets. Halley can be seen from the Earth every 75 years. The last time was in 1986, the next time will be in 2061. Despite his regular return, the comet’s orbit cannot be predicted exactly. This is partly due to processes inside the comet and partly because the orbit of Halley is disturbed by the chaotic interaction with the planets and minor bodies in the solar system.

Stable

The prevailing view among astronomers is that the orbit of Halley’s comet cannot be calculated exactly because the orbit would be chaotic on a time scale of only seventy years. The team of astronomers has now shown that the comet’s orbit is stable for more than three hundred years. That’s much longer than expected.

Venus

‘We did the most accurate calculations of Halley and the planets ever,’ said researcher Tjarda Boekholt (Leiden University). ‘To our surprise Halley’s orbit was most strongly influenced by the planet Venus and not by Jupiter, the planet that was always pointed to as the biggest spoiler.’

Jupiter

In about three thousand years the comet will approach the planet Jupiter relatively close, so Halley will get a big push. From then on Venus will no longer be the main perturber and Jupiter will take over this role. ‘After that predictions of the orbit become less accurate, because the precise effect of Jupiter’s gravity introduces a relatively large error in our calculations,’ says fellow researcher Inti Pelupessy (Leiden University).

Tyrannosaur in Dutch museum’s name is Trix


This 2015 Dutch video is about the Tyrannosaurus rex which is now in Naturalis museum in Leiden in the Netherlands.

The Tyrannosaurus rex, excavated in Montana in the USA in 2013, will be exhibited in Naturalis from 10 September 2016 on.

This dinosaur is said to be ‘an old lady’.

Today, Dutch NOS TV reports that her name will be Trix. An abbreviation of Beatrix, the name of Princess Beatrix, ex-queen of the Netherlands.

See also here.

Zebra finches and sounds, new research


This video says about itself:

26 November 2015

Researchers said zebra finch pairs appear to ‘discuss’ their parental duties. If one of them is late they ‘negotiate’ how long the other should spend away from the nest when they go foraging.

From Leiden University in the Netherlands:

Male birds may sing, but females are faster at discriminating sounds

Published on 12 May 2016

It may well be that only male zebra finches can sing, but the females are faster at learning to discriminate sounds. Leiden researchers publish their findings in the scientific journal Animal Behaviour.

The scientists reached this conclusion after a meta-analysis of different experiments with the songbirds. Combining the results of 14 separate studies gave them a population of 87 birds to work from. The aim of the research was to find out why some birds could recognise sounds faster than others.

Go and no-go

The zebra finches heard one of two sound types after pecking at an LED sensor. If – after hearing the right sound (the ‘go sound’) – they pecked on the sensor again, they received a reward. Pecking on the sensor after hearing the so-called no-go sound gave them no reward, and even ‘punished’ the birds by leaving them in the dark for a short while.

Dr Pralle Kriengwatana: ‘Our meta-analysis shows that female zebra finches learn to discriminate sounds faster, which is surprising considering that females don’t sing. On the basis that male songbirds usually sing more than female songbirds, scientists have long assumed that the males must also be better at recognising and learning song (and perhaps also other sounds). It now seems that sex differences in producing complex sounds do not necessarily correlate exactly with the ability to perceive and discriminate these complex sounds.’

Cause unknown

The scientists are still in the dark about the reasons why females learn better than males, although the female hormone oestrogen may play a role. According to Kriengwatana, further research is needed to determine the precise cause of the sex differences.

The researchers also discovered that the zebra finches try out different theories in their efforts to understand the test. In the first instance some birds stop pecking as soon as they hear new sounds, and then start pecking after each sound (both ‘go’ and ‘no-go’). Once they realise that pecking after the ‘no-go’ sound does not bring them any reward, they peck much less after this sound. The other group of birds also initially stop pecking, and then slowly but surely start pecking on the LED sensor again after both sounds. As soon as they understand that the ‘go’ sound gives them food, they peck more after hearing this sound.

Family size and body mass

Surprisingly enough, family size and body mass also seem to play a role. The finches from larger nests learned to distinguish sounds faster than birds with fewer siblings. The same applied for finches that weighed more at the age when they learned to eat by themselves and stop relying on parents for food. One explanation could be that more contact with other birds and better health may promote the faster recognition of sounds.

Zebra finch moms sing songs of rising temps to warn developing chicks to slow their growth: here.

Mammoth fur, excrement in Dutch museum


This is a 29 April 2016 video from Naturalis museum in Leiden, the Netherlands. It shows pieces of woolly mammoth fur and excrement arriving in the collection, all the way from the permafrost in Siberia.

Museum biologists at work, video


This 7 April 2016 video from Leiden in the Netherlands is called At the laboratories of Naturalis Biodiversity Center.