An absolute description of the threat hanging over the world's mammals,reptiles,amphibians and other life forms has been published by the well-known scientific journal,Nature.A special analysis carried out by the journal indicates that an astonishing 41% of all amphibians on the planet now face extinction while 26% of mammal species and 13% of birds are similarly threatened.

    Many species are already critically endangered and close to extinction,including the Sumatran elephant,Amur leopard and mountain gorilla.But also in danger of vanishing（消失）for the wild,it now appears,are animals that are currently rated as merely being endangered.

    In each case,the finger of blame points directly at human activities.The continuing spread of agriculture is destroying millions of hectares of wild habitats every year,leaving animals without homes,while the introduction of newly-come species,often helped by humans,is also damaging native populations.At the same time,pollution and overfishing are destroying ocean ecosystems.

    "Habitat destruction,pollution or overfishing either kill off wild creatures and plants or leaves them badly weakened," said Derek Tittensor,an ocean ecologist at the World Conservation Monitoring Centre in Cambridge. "The trouble is that in coming decades,the additional threat of worsening climate change will become more and more common and could then kill off these survivors."

    The problem,according to Nature,is worsened because of the huge gaps in scientists knowledge about the planet's biodiversity.Evaluations of the total number of species of animals and plants alive vary from 2 million to 50 million.In addition,evaluations of current rates of species' disappearances vary from 500 to 36,000 a year. "That is the real problem we face," added Tittensor. "The scale of uncertainty is huge."

    In the end,however,the data indicate that the world is heading cruelly towards a mass extinction-which is defined as one involving a loss of 75% of species or more.This could arrive in less than a hundred years or could take a thousand,depending on extinction rates.

    The best bikes for the beginners

    When it comes to purchasing your first bike, the choice is endless, making it tough to know what to go for. Here are the best buys on the market right now.

    Boardman CX Comp

    This is a cross-country bike, and it's so versatile(多用途的)that you can handle any terrain(地势)on it, making it a great choice for those wanting to try various cycling subjects. If you leave on the thick tires it comes with, it can ride on various paths and can even handle some less demanding mountain bike routes. Alternatively, put on thin, slick tires and treat it as a road bike. It has basket and comes with Shimano Sora gears(齿轮), which are outstanding for its price.

    $650, Halfords

    Planet X RT-58 v2

    Planet X is based in Yorkshire, which means you'd probably have to buy this bike without seeing it. But it's worth it, because this is an excellent machine at a lower price. Planet X is a highly rated manufacture and this model comes with Shimano Sora gears.

    $439, Planet X

    Specialized Allez ES

    Specialized is one of the biggest and most popular brands in cycling, and this is its hugely popular primary road bike. It comes with solid components from front to back and you'll look great out on the road.

    $575, Evans Cycles

    Boardman Road Team Carbon

    If you can push budget further still, this bike is worth the extra investment. The frame is made entirely from carbon, which is lighter, faster and more comfortable than the composition metal models above and gives you an all-round more enjoyable ride. It also means that if you get really serious about cycling, you don't have to upgrade as quickly as you would with a cheaper bike.

    $800, Halfords

    Ray Tokuda, a 54-year-old Japanese American, is proud of the title his school has given him. He is a Shifu, a Chinese word literally meaning a master, mentor or senior practioner of martial arts.

    Tokuda has reason to be proud. He has been involved with Chinese martial arts for almost four decades. After learning them at the martial arts school in New Mexico State, today he is among the most experienced kung fu teachers of the school.

    Practicing martial arts two to three hours and helping students improve their skills have become Tokuda's daily routine. He expects to practice and teach martial arts for the rest of his life. "I'm still learning. It's worth more than a lifetime to learn Chinese martial arts," he said. "Once I started, I just couldn't stop. I think it's also the magic of Chinese culture."

    Tokuda was sent to the martial arts school when he was 10. He still remembers how unwilling he was when starting out. "My father had always wanted to learn Chinese martial arts but never got the chance, so he put his kid in," he said. "I was so afraid at that time because I thought kung fu was all about fighting."

    But things changed after he learned that martial arts were more than punching and kicking.

    "One of the things martial arts teach me is overcoming adversity," Tokuda said. "As a little kid, my first lesson was like, oh, look, this is a thing that I can get through by diligence, perseverance（毅力）and dedication, and that was priceless for my life."

    Learning Chinese martial arts opened a gateway for him to better understand Chinese culture because he could hear a lot of ancient Chinese kung fu-related stories. "It is like in America, where we hear stories about knights in shining armor and King Arthur and noble deeds done," he said. "I feel martial arts preserve something of ancient China that can't be found in books. They are sort of an oral history."

    Tokuda has also been invited to various events in his home state to showcase traditional Chinese culture, including the dragon dance and lion dance, which he also learnt at the martial arts school. Because of this, he is now considered a cultural envoy (使者) in the eyes of the public.

    Any foreigner who has tried to learn Chinese can tell how hard it is to master the tones required to speak and understand. And anyone who has tried to learn to play the violin or other instruments can report similar challenges.

    Now researchers have found that people with musical training have an easier time learning Chinese. Writing in the online edition of Nature Neuroscience，researchers from Northwestern University say that both skills draw on the same parts of the brain that help people discover changes in pitch(音调).

    One of the study's authors，Nina Kraus，said the findings suggested that studying music "actually tunes our sensory system" .This means that schools that want children to do well in languages should hesitate before cutting music programs，Dr. Kraus said. She said music training might also help children with language problems.

    Mandarin(普通话)speakers have been shown to have a more complex encoding(编码) of pitch patterns in their brains than English speakers do. This is because in Mandarin and other Asian languages，pitch plays a central role. A single­syllable word can have several meanings depending on how it is intoned.

    For this study，the researchers looked at 20 non­Chinese speaking volunteers，half with no musical background and half who have studied an instrument for at least six years.

    As they were shown a movie，the volunteers also heard an audio tape of the Mandarin word “mi” in three of its meanings: squint，bewilder and rice. The researchers recorded activities in their brain stems to see how well they were processing the sounds. Those with a music background showed much more brain activities in response to the Chinese sounds.

    The lead author of the study，Patrick C.M. Wong，said it might work both ways. It appears that native speakers of tonal languages may do better at learning instruments.

    We work with Cambridge County Council's Participation Team to create opportunities for young people to visit the University and learn more about it. The following events are scheduled for the 2019/2020 academic year.

    SuperStar workshops

    12 workshops are planned for young people aged 7 to 11. These half-day visits will be held throughout the year, at times when young people are not at school. If participants complete 8 of the 12 workshops, they will be awarded the nationally recognized SuperStar Crest Award.

    Please note, workshops will only run if we have a sufficient number of attendees (usually around 3+ participants).

    Explore University Days

    Explore University Days are for young people aged 12-15. Participants visit the University for two days and take part in a variety of university-related workshops, and other fun activities.

    Previous participants have joined in the following:

    • Visited the Sports Centre

    • Took part in a Neuroscience workshop

    • Enjoyed a two-course meal at a University College

    Dates will be confirmed in early December 2019, and a schedule for event will follow in the New Year.

    Events for post-16 students

    If you are studying for your post-16 qualifications and are considering applying for Cambridge or would like to find out more about a specific subject, the following events might be for you:

    • University and College Open Days

    • Subject Masterclasses

    • Cambridge Science Festival