Rafting the GRAND CANYON Welcomes You!

    For an exciting，fun and challenging white water tours，Rafting the GRAND CANYON is here to help you plan the right tour for you. Whether you want to travel for two days or ten，hike in or not，go on an oar raft or motorized trip，we will help you find the trip that meets your needs.

    For those who will be vacationing on the off­season a trip on the Native American Red River rafting is available year around or a one ­day trip is available on the Colorado River from Diamond Creek to Pierce Ferry (about three hours from Las Vegas)．

    Most of the trips depart from Lees Ferry，Arizona (approximately 21/2 hours from the south rim of the Grand Canyon)．We offer partial trips which allow you to get on or off at Phantom Ranch located at the bottom of the Grand Canyon National Park South Rim. Requiring a hike in or out，with proper planning the horse ride up or down is also an option. Most trips occur between April and October.

    Since all rafting on the Colorado requires a permit，planning and reserving your trip requires reservations well in advance. Please let us know when you would like to go and we will contact all the river concessionaires (特许权获得者)to help you find the best trip for you.

    For planning your trip，questions，concerns or to make your reservations，please email or call the toll free number below. Since these trips are limited we highly recommend you make your reservations months in advance.

    To talk to a live person call us toll free：1­800­222­6966 or 702­655­6060

    If you have any questions regarding a trip，please CLICK_HERE to fill out our form. This will speed up the process of getting you accurate information regarding your trip.

    If you would like to send us an email other than about an up­coming trip you can contact us at info@raftingthegrandcanyon.com.

    We look forward to helping you plan your trip! (Please NO Travel Agents)

    City College

    ADMISSION REQUIREMENTS

    All high school graduates and anyone 18 years of age or older, with or without a high school diploma, are suitable for admission. Individuals under the age of 18 who possess a high school diploma are also suitable for admission.

    HOW TO ENROLL IN CREDIT COURSES

    New and readmitted students must complete and hand in a credit admissions application form available online at www.ccsf.edu.

    BEFORE YOU REGISTER:

    Learn about your skill level in English and Math through our assessment service;

    Attend an orientation (新生报到会) to hear about support services

    Meet with a counselor (adviser) to select your courses;

    Find out if you are required for attending the entrance examinations.

    HOW TO ENROLL IN NONCREDIT COURSES

    Courses in Noncredit Programs are free of charge (no enrollment fee). For information on how to enroll in noncredit courses, click here.

    PARKING

    Students, faculty and staff are encouraged to use public transit. Click here for Parking Regulations.

    SERVICES

    City College services include a bookstore, cafeteria, health center, tutoring center, career and transfer center, counseling, financial aid, library, learning resource center, student government offices, campus police, disabled students programs and more.

    Antarctica(南极洲)'s melting ice, which has caused global sea levels to rise by at least 13.8 millimeters over the past 40 years, was thought to primarily come from the unstable West Antarctic Ice Sheet(WAIS). Now, scientists have found that the East Antarctic Ice Sheet (EAIS)—considered largely unaffected by climate change—may also be melting at an unexpectedly rapid speed.

    The WAIS, whose base is below sea level, has long been considered the most likely to break down. Besides gravity, a deep current of warm water slips beneath the sheet, melting it from below until it becomes a floating shelf at risk of breaking away. In contrast, extreme cold and a base mostly above sea level are thought to keep the EAIS relatively safe from warm waters.

    But as greenhouse gases warm much of the planet, driving stronger polar winds, some scientists think warm water carried by a circular current will start to invade East Antarctica's once unassailable ice. A cooperation of more than 60 scientists last year, published in Nature, estimated that the EAIS actually added about 5 billion tons of ice each year from 1992 to 2017.

    Eric Rignot of the University of California, Irvine, and colleagues combined 40 years of satellite imagery and climate modeling and found that overall Antarctica now sends six times more ice into the sea each year than it did in 1979, with the majority coming from West Antarctica. But East Antarctica was responsible for more than 30% of Antarctica's contribution to the 13.8-millimeter sea level rise over the past 40 years. “The more we look at this system the more we realize this is fragile,” Rignot says. “Once these glaciers become unstable there is no red button to press to stop it.”

    Rignot hopes the study brings greater attention to a part of Antarctica that has traditionally been understudied. Helen Fricker, a glaciologist (冰川学家) in California, agrees. “We need to monitor the entire Antarctica and we just can't do that without international cooperation.”

    You may not have heard of it before, but solid rain (固体雨)has been helping Mexican farmers fight droughts(干旱) for over ten years. The magic solid rain looks like sugar and it can take in water up to 500 times as its own size and keep it in the ground for up to a year.

    The story of solid rain began in 1970, when American scientists developed a product used to take in water and help keep babies' bottoms dry. However, a Mexican chemical engineer saw this magic product as an opportunity to fight the drought. He developed a different kind of the product, which could be mixed with soil and slowly feed water to crops over a long period of time. His company, Solid Rain, has been quietly selling the product to Mexican farmers for over 10 years.

    Solid rain seems to be working wonders in Mexico. However, it has not come into use around the world. Well, that's mainly because a lot of people still don't know about it. The Mexican company has invested (投资) almost nothing into marketing, relying instead on word of mouth between Mexican farmers. However, recently, they have gotten requests from other dry countries like India and Australia.

    Solid rain has received the Ecology and Environment Award, but it has also received some negative views. Dr. Linda Scott says that the product is hardly new and that there is no scientific evidence that it can hold water for a year or last in the ground for ten years. Besides, solid rain can cause more harm than good in certain conditions.

    However, real-life use seems to show that solid rain is actually of great use to their farms. Frank Torres, a former green bean farmer used to rely on it even though drought wasn't such a big issue. He said that the production had increased by 50%.

An Edinburgh inventor has created a fully biodegradable bottle that is made from paper and a secret combination of plant materials, and it could help save the planet's oceans from plastic pollution and can also be eaten by sea creatures.

The Edinburgh-based Durham University chemistry graduate James Longcroft started a non-profit bottled water company two years ago. He wanted to put all his profits into a charity that provided clean drinking water to countries in Africa.

However, after concerns about the environmental impact of plastic bottles, Mr. Longcroft decided the Edinburgh and London-based company, Choose Water, should go plastic-free. So he came up with a new type of water bottle—a waterproof paper bottle.

"The outside is made from recycled paper, but the inside has to be waterproof, and provides strength so the bottle would keep its structure, and keep the water fresh," Mr. Longcroft said.

When the bottle is thrown in the ocean the degrading process begins within hours leaving the bottle totally degraded (分解)within weeks. The steel cap breaks down within a year.

Mr. Longcroft now believes these novel bottles could revolutionise the industry and says the cost of producing the bottle is around 5 pence more than one made from single-use plastic.

"The main difficulty we face is breaking into a saturated (饱和的)market and competing with an old industry," he said. "Changing an industry will be a big uphill battle, but with the support from the public, we will change the way we look at bottled water."

Researchers warn that eight million tonnes of plastics currently find their way into the ocean every year which will stay in the environment for centuries.

"We really want to get our bottles on shelves and into people's hands as soon as possible—if we can stop even one plastic bottle ending up in the environment it will be worth it," said Mr Longcroft.

Ivan Pavlov was a Russian physiologist (生理学家) best known for his discovery of classical conditioning (经典条件反射). During his studies on the digestive systems of dogs, Pavlov found that the animals salivated (流口水) naturally upon the presentation of food. However, he also noticed that the animals began to salivate whenever they saw the white lab coat of an experimental assistant. By associating the presentation of food with the lab assistant, he finally found that a dog would salivate to the presence of a stimulus (刺激物) other than food. He called this response a conditional reflex.

Ivan Pavlov was born in a small village in Ryazan. Russia, where his father was the village minister. His earliest studies were focused on theology (神学), but reading Charles Darwin's On the Origin of Species had a powerful influence on his future interests. He soon stopped his religious studies and devoted himself to the study of science at the University of Saint Petersburg. Pavlov's interests were the study of physiology and natural sciences. He helped found the Department of Physiology at the Institute of Experimental Medicine and continued to manage the program for the next 45 years.

Pavlov received much praise for his work. He worked in the Russian Academy of Science and won the 1904 Nobel Prize in Physiology. The Soviet government also offered lots of support for Pavlov's work, and the Soviet Union soon became a leading center of research on physiology. While Ivan Pavlov was not a psychologist, and reportedly disliked the field of psychology, his work had a major influence on the field, particularly on the development of behaviorism. His discovery and research on reflexes influenced the growing behaviorist movement. and Pavlov's discovery had a major influence on many thinkers, such as John B. Watson.