巢湖足解剖模型来宾人体浅层运动肌肉解剖模型,全功能新生儿高级模拟人购买,西藏人体解剖挂图-泌尿生殖系统,西安女性泌尿生殖系统解剖模型,江苏无线PAD版全自动多种穿刺模拟教学系统,新疆颈深层肌肉解剖模型,沈阳牙护理保健模型（28颗牙，放大5倍）

After almost two years circling an ancient asteroid hundreds of millions of miles away, a NASA spacecraft this week will attempt to descend to the treacherous, boulder-packed surface and snatch a handful of rubble.The drama unfolds Tuesday as the U.S. takes its first crack at collecting asteroid samples for return to Earth, a feat accomplished so far only by Japan.Brimming with names inspired by Egyptian mythology, the Osiris-Rex mission is looking to bring back at least 2 ounces (60 grams) worth of asteroid Bennu, the biggest otherworldly haul from beyond the moon.The van-sized spacecraft is aiming for the relatively flat middle of a tennis court-sized crater named Nightingale — a spot comparable to a few parking places here on Earth. Boulders as big as buildings loom over the targeted touchdown zone.“So for some perspective, the next time you park your car in front of your house or in front of a coffee shop and walk inside, think about the challenge of navigating Osiris-Rex into one of these spots from 200 million miles away,” said NASA’s deputy project manager Mike Moreau.Once it drops out of its half-mile-high (0.75 kilometer-high) orbit around Bennu, the spacecraft will take a deliberate four hours to make it all the way down, to just above the surface.Then the action cranks up when Osiris-Rex’s 11-foot (3.4-meter) arm reaches out and touches Bennu. Contact should last five to 10 seconds, just long enough to shoot out pressurized nitrogen gas and suck up the churned dirt and gravel. Programmed in advance, the spacecraft will operate autonomously during the unprecedented touch-and-go maneuver. With an 18-minute lag in radio communication each way, ground controllers for spacecraft builder Lockheed Martin near Denver can’t intervene.If the first attempt doesn’t work, Osiris-Rex can try again. Any collected samples won’t reach Earth until 2023.While NASA has brought back comet dust and solar wind particles, it’s never attempted to sample one of the nearly 1 million known asteroids lurking in our solar system until now. Japan, meanwhile, expects to get samples from asteroid Ryugu in December — in the milligrams at most — 10 years after bringing back specks from asteroid Itokawa.Bennu is an asteroid picker’s paradise.The big, black, roundish, carbon-rich space rock — taller than New York’s Empire State Building — was around when our solar system was forming 4.5 billion years ago. Scientists consider it a time capsule full of pristine building blocks that could help explain how life formed on Earth and possibly elsewhere.“This is all about understanding our origins,” said the mission’s principal scientist, Dante Lauretta of the University of Arizona.There also are selfish reasons for getting to know Bennu better.The solar-orbiting asteroid, which swings by Earth every six years, could take aim at us late in the next century. NASA puts the odds of an impact at 1-in-2,700. The more scientists know about potentially menacing asteroids like Bennu, the safer Earth will be.When Osiris-Rex blasted off in 2016 on the more than 0 million mission, scientists envisioned sandy stretches at Bennu. So the spacecraft was designed to ingest small pebbles less than an inch (2 centimeters) across.Scientists were stunned to find massive rocks and chunky gravel all over the place when the spacecraft arrived in 2018. And pebbles were occasionally seen shooting off the asteroid, falling back and sometimes ricocheting off again in a cosmic game of ping-pong.With so much rough terrain, engineers scrambled to aim for a tighter spot than originally anticipated. Nightingale Crater, the prime target, appears to have the biggest abundance of fine grains, but boulders still abound, including one dubbed Mount Doom.Then COVID-19 struck.The team fell behind and bumped the second and final touch-and-go dress rehearsal for the spacecraft to August. That pushed the sample grab to October.“Returning a sample is hard,” said NASA’s science mission chief, Thomas Zurbuchen. “The COVID made it even harder.”Osiris-Rex has three bottles of nitrogen gas, which means it can touch down three times — no more.The spacecraft automatically will back away if it encounters unexpected hazards like big rocks that could cause it to tip over. And there’s a chance it will touch down safely, but fail to collect enough rubble.In either case, the spacecraft would return to orbit around Bennu and try again in January at another location.With the first try finally here, Lauretta is worried, nervous, excited “and confident we have done everything possible to ensure a safe sampling.”___The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content. 4807

After initially being deadlocked on a vote to certify election results, The Wayne County Board of Canvassers voted unanimously to certify election results Tuesday evening. The motion to hold another vote came following hours of public comments condemning Republican canvassers' decisions to vote against the certification.The board of canvassers vote initially tied 2 to 2 along party lines. But just before 9:30 p.m. Tuesday, the board filed a motion and voted to certify the results under the stipulation that Secretary of State Jocelyn Benson does a comprehensive audit of the election in the county.President Trump also tweeting praise to canvassers who initially blocked the certification, saying "Wow! Michigan just refused to certify the election results! Having courage is a beautiful thing. The USA stands proud!"There has been a whirlwind of unproven allegations of fraud and a string of lawsuits since the election two weeks ago. The canvassers' initial vote came after many Detroit precincts were found to be out of balance.That means the number of votes are not in line with the number of voters. However, the variance is said to be small with no evidence of fraud or systemic failure. 1206

After two and a half weeks of historic destruction, the Camp Fire in Northern California is 100% contained, but the search for remains threatens to push the death toll over 85, where it stood early Sunday.It's already the state's deadliest fire.Officials found two bodies in Paradise and another in Magalia, both of which sit just west of the Plumas National Forest, roughly 100 miles north of Sacramento.Since it began November 8, the fire has destroyed almost 14,000 homes, 514 businesses and 4,265 other buildings. It has covered more than 153,000 acres, roughly the size of Chicago.Cal Fire, the state's forestry and fire protection agency, announced the fire was completely contained early Sunday. As of Saturday evening, the uncontained portion of the fire was along steep terrain unsafe for firefighters due to recent heavy rains, the agency said.More than 2,500 people are now accounted for, according to the Butte County Sheriff's Office. While 251 people remain missing, the sheriff's office says, that number is down from more than 1,000 just a few days ago.The sheriff's office is maintaining a public list of missing people and offering to swab the cheeks of immediate relatives in hopes of identifying those lost in the fire. 1247

After 3,750+ Professional and Olympic hockey games, 100 different verbs used to describe a pass or shot, and 22 Stanley Cup Finals, the legendary Mike "Doc" Emrick has announced his retirement from broadcasting.From hockey fans around the world, we say #ThankYouDoc! pic.twitter.com/Pt27Dp63TW— #ThankYouDoc (@NHLonNBCSports) October 19, 2020 350

After years of struggling, one Kansas mother finally has peace of mind. She can now walk through the park with her daughters free of fear. However, living without fear doesn’t mean living without worry.“It feels unsafe to be who you are sometimes,” said J, a mother of two living in Lawrence, Kansas. The mother wishes to be called J in order to protect her identity, because even in a community where legally she should be safe, J is still concerned.“We know what it's like to be living in fear…to have that uncertainty,” said J, referring to her years growing up undocumented in the United States. Now, even though she is a citizen, she worries the current administration will find ways to strip her of her rights.Growing up undocumented taught J about a different side of the American dream. It meant asking neighbors to use their name for utilities and not accessing community resources.“Calling the police on someone…definitely we stopped ourselves because we don't want those questions,” said J.She saw the same fear in her own daughter’s eyes as her family worked for over four years for her husband to become documented.“Our daughter has asked what would happen to her dad if he was pulled over. Would he be taken away? It’s just a constant fear of are your parents going to come home that day?”Now that her family is documented, J wants to use her voice to help others in her community stop feeling that same worry. It’s a feeling she’s still confronting herself, especially after Immigration and Customs Enforcement raids last year ended in the wrong man getting arrested and federally detained in her own community, a typically quiet college town.“You can't even walk without looking the way that we look and someone saying, ‘I bet that person is undocumented, and they're probably a criminal, so let's get them,’” said J.So, she joined a group called Sanctuary Alliance, a grass-roots movement fighting to designate the city of Lawrence as a sanctuary city.It took a year of meetings and discussions, but just weeks ago, the city commission voted.The sanctuary ordinance was approved.So, what does it mean to be a sanctuary city? The Lawrence, Kansas ordinance says: no city department can ask about immigration status, including the police and the court system; Anytime an ID is required, a resident can present identification valid in their home country; all city services, including transit, parks and utilities are available to all residents, regardless of immigration status; and if anyone asks about their status, there are ways people can safely report violations to the city.“It’s a big step toward creating safety for the community,” said J. “People think that becoming a sanctuary city will bring criminals in because obviously undocumented people are criminals. They're not. Statistically, a sanctuary city will become safer because the citizens who are undocumented will now not be afraid to call the police."Safety in this community is just the start of the conversation. Sanctuary Alliance is now pushing for a county-wide sanctuary to help more families live life outside the shadows.But while that fight continues, J takes comfort in hey city’s ordinance bringing a new era of unity this community has never seen before.“There's still some work that needs to be done, but it will make it better,” said J. 3340