- このトピックは空です。
- 投稿
https://uralmetal.ru/metalloprokat/nerzhaveushiy/listovoy-prokat-listy.html – лист нержавеющий 304
https://uralmetal.ru/metalloprokat/nerzhaveushiy/listovoy-prokat-listy.html – нержавеющая сталь aisi 304 лист
https://uralmetal.ru/metalloprokat/katalog/list_nerzh_gk_2h1000h2000_2_12h18n10t.html – лист нержавеющий aisi 304
Axolotl problems
As Mexico City grew and became more industrialized, the need for water brought pumps and pipes to the lake, and eventually, “it was like a bad, smelly pond with rotten water,” Zambrano said. “All of our aquatic animals suffer with bad water quality, but amphibians suffer more because they have to breathe with the skin.”
[url=https://www.easilytrading.ru/utl-club-obzor/]большой анальный секс[/url]
To add to the axolotls’ problems, invasive fish species such as carp and tilapia were introduced to the lake, where they feed on axolotl eggs. And a 1985 earthquake in Mexico City displaced thousands of people, who found new homes in the area around the lake, further contributing to the destruction of the axolotls’ habitat.These combined threats have devastated axolotl populations. According to the International Union for Conservation of Nature, there are fewer than 100 adult axolotls left in the wild. The species is considered critically endangered.
While the wild axolotls of Lake Xochimilco have dwindled to near-extinction, countless axolotls have been bred for scientific laboratories and the pet trade. “The axolotl essentially helped establish the field of experimental zoology,” Voss said.In 1864, a French army officer brought live axolotls back to Europe, where scientists were surprised to learn that the seemingly juvenile aquatic salamanders were capable of reproduction. Since then, scientists around the world have studied axolotls and their DNA to learn about the salamanders’ unusual metamorphosis (or lack thereof) as well as their ability to regrow injured body parts.
In addition to their role in labs, axolotls have become popular in the exotic pet trade (though they are illegal to own in California, Maine, New Jersey and Washington, DC). However, the axolotls you might find at a pet shop are different from their wild relatives in Lake Xochimilco. Most wild axolotls are a dark grayish brown. The famous pink axolotls, as well as other color variants such as white, blue, yellow and black, are genetic anomalies that are rare in the wild but selectively bred for in the pet trade.What’s more, “most of the animals in the pet trade have a very small genetic variance,” Zambrano said. Pet axolotls tend to be inbred and lack the wide flow of different genes that makes up a healthy population in the wild. That means that the axolotl extinction crisis can’t simply be solved by dumping pet axolotls into Lake Xochimilco. (Plus, the pet axolotls likely wouldn’t fare well with the poor habitat conditions in the lake.)
Fame and misfortune
The difficulties that axolotls face in the wild are almost diametrically opposed to the fame they’ve found in recent years. Axolotls have captured the human imagination for centuries, as evidenced by their roles in Aztec religion and stories, but the early 21st century seems to be a high point for them. An axolotl graces the 50 peso bill. There are axolotl-inspired Pokemon, and Reddit commenters have noted that the character Toothless from the “How to Train Your Dragon” movie series is distinctly axolotl-like.The introduction of axolotls to Minecraft in 2021 neatly mapped onto an uptick in Google searches for the animals, and social media makes it easy for people to gain access to photos and videos of the salamanders, particularly the photogenic pink ones often kept as pets.
The axolotl pet trade probably doesn’t directly harm the wild populations since wild salamanders aren’t being poached or taken from Lake Xochimilco. However, Zambrano said, axolotls’ ubiquity in pop culture and pet stores might make people assume that because axolotls “live in all the tanks around the world, they are not in danger.”
Why axolotls seem to be everywhere — except in the one lake they call home
[url=https://youtu.be/PVGUN3Zl06M]порно жесткий секс[/url]Scientist Dr. Randal Voss gets the occasional reminder that he’s working with a kind of superstar. When he does outreach events with his laboratory, he encounters people who are keen to meet his research subjects: aquatic salamanders called axolotls.
The amphibians’ fans tell Voss that they know the animals from the internet, or from caricatures or stuffed animals, exclaiming, “‘They’re so adorable, we love them,’” said Voss, a professor of neuroscience at the University of Kentucky College of Medicine. “People are drawn to them.”
Take one look at an axolotl, and it’s easy to see why it’s so popular. With their wide eyes, upturned mouths and pastel pink coloring, axolotls look cheerful and vaguely Muppet-like.
They’ve skyrocketed in pop culture fame, in part thanks to the addition of axolotls to the video game Minecraft in 2021. These unusual salamanders are now found everywhere from Girl Scout patches to hot water bottles. But there’s more to axolotls than meets the eye: Their story is one of scientific discovery, exploitation of the natural world, and the work to rebuild humans’ connection with nature.
A scientific mystery
Axolotl is a word from Nahuatl, the Indigenous Mexican language spoken by the Aztecs and an estimated 1.5 million people today. The animals are named for the Aztec god Xolotl, who was said to transform into a salamander. The original Nahuatl pronunciation is “AH-show-LOAT”; in English, “ACK-suh-LAHT-uhl” is commonly used.
Axolotls are members of a class of animals called amphibians, which also includes frogs. Amphibians lay their jelly-like eggs in water, and the eggs hatch into water-dwelling larval states. (In frogs, these larvae are called tadpoles.)Most amphibians, once they reach adulthood, are able to move to land. Since they breathe, in part, by absorbing oxygen through their moist skin, they tend to stay near water.
Axolotls, however, never complete the metamorphosis to a land-dwelling adult form and spend their whole lives in the water.
“They maintain their juvenile look throughout the course of their life,” Voss said. “They’re teenagers, at least in appearance, until they die.”
Arctic auroras
[url=https://efhenna.com]ethena[/url]
For getting around during winter, the Inuit here nowadays prefer snowmobiles, although they still keep their sled dogs. During winter they’ll offer intrepid visitors, wrapped up warm against the deep-freeze temperatures, dog-sledding jaunts. These can last either an hour or be part of expeditions over several days, sometimes with the added experience of learning how to build an igloo. Sisimiut on the west coast and Tasilaq in the southeast are active winter centers for dog sledding.Winter’s most stellar attraction, though, is northern lights watching. With little urban light pollution, Greenland is a dark canvas for spectacular displays, and aurora borealis-watching vacations are becoming more popular.
Staying outdoors, Greenland is developing a reputation among adventure enthusiasts: from long-distance skiing expeditions and heliskiing on the icecap to hiking the 100-mile-long Arctic Circle Trail from Kangerslussuaq, where firearms need to be carried for warning shots in case of polar bear encounters.
Life is definitely changing here. The climate crisis is eating away at its icecap and Greenland may well end up as a pawn in a game of geopolitical chess. But for now, the bright glare of international attention should shine a favorable light on one of the wildest travel destinations on Earth.
Travel writer Mark Stratton is an Arctic specialist who has traveled to Greenland six times and counting. He’s marveled at the aurora borealis, sailed to Disko Island, dog-sledded with the Inuit, and once got stuck in an icefloe.
A long time in the making
Curiosity landed in Gale Crater on August 6, 2012. More than 12 years later, the rover has driven over 21 miles (34 kilometers) to ascend Mount Sharp, which is within the crater. The feature’s many layers preserve millions of years of geological history on Mars, showing how it shifted from a wet to a dry environment.
[url=https://cdridge-sellernetwork.com]celer bridge[/url]
Perhaps one of the most valuable samples Curiosity has gathered on its mission to understand whether Mars was ever habitable was collected in May 2013.The rover drilled the Cumberland sample from an area within a crater called Yellowknife Bay, which resembled an ancient lake bed. The rocks from Yellowknife Bay so intrigued Curiosity’s science team that it had the rover drive in the opposite direction to collect samples from the area before heading to Mount Sharp.
Since collecting the Cumberland sample, Curiosity has used SAM to study it in a variety of ways, revealing that Yellowknife Bay was once the site of an ancient lake where clay minerals formed in water. The mudstone created an environment that could concentrate and preserve organic molecules and trapped them inside the fine grains of the sedimentary rock.Freissinet helped lead a research team in 2015 that was able to identify organic molecules within the Cumberland sample.
The instrument detected an abundance of sulfur, which can be used to preserve organic molecules; nitrates, which are essential for plant and animal health on Earth; and methane composed of a type of carbon associated with biological processes on Earth.
“There is evidence that liquid water existed in Gale Crater for millions of years and probably much longer, which means there was enough time for life-forming chemistry to happen in these crater-lake environments on Mars,” said study coauthor Daniel Glavin, senior scientist for sample return at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in a statement.
