World Elephant Day is the perfect time to find out more about these amazing animals and what we can do to preserve them so they do not go the way of the mammoth（猛犸象）.

    World Elephant Day was created in 2011 by two Canadian filmmakers Patricia Sims and Thailand's Elephant Reintroduction Foundation and was first celebrated on August 12, 2012. They made the documentary Return to the Forest, a fascinating 30 minute film about the reintroduction of caught Asian elephants to the wild.

    Currently, the demand for ivory（象牙）is becoming bigger and bigger, whose price is higher than that of gold, making elephants bigger targets than ever. Habitation loss is also a danger to the world's elephant population as it robs elephants of the hundreds of pounds of food they need every day, making it more difficult for them to breed and making it easier for hunters to track them down. Circuses and tourism are also serious threats to the animals' well-being.

    The best way to celebrate this day is to take the opportunity to educate yourself about these magnificent（巨大的）mammals and share your knowledge with others. As ever, simply spreading the word about the dangers these magnificent mammals face via social media can actually make a real change. Expose that “training” elephants often involves tying and beating them daily for months on end. If you want to get a bit more involved, you could choose to make a donation to a foundation dedicated to protecting elephants from hunters or relocating them to locations better suited to their needs.

    Whichever way suits you best, make sure that you spend this day in a way that helps elephants all over the world, so we, in turn, can continue to wonder at them and their uniquely fascinating way of life.

Hot Air Balloons

    The basis of how the balloon works is that warmer air rises in cooler air. This is because hot air is lighter than cool air as it has less mass per unit of volume. Mass can be defined by the measure of how much matter something contains. The actual balloon has to be large as it takes a large amount of heated air to lift it off the ground.

    The burner uses propane gas to heat up the air in the envelope to move the balloon off the ground and into the air. The pilot must keep firing the burner at regular intervals throughout the flight to ensure that the balloon continues to the stable. Naturally, the hot air will not escape from the hot at the very bottom of the envelop as firstly, hot air rises and secondly, the floating power keeps it moving up.

    To move the balloon upwards, the pilot opens up the propane value which lets the propane flow to the burner which in turn frees the flame up into the envelope. It works in much the same way as a gas grill: the more you open the valve, the bigger the flame to beat the air and the faster the balloon rises.

    The “Parachute Valve” at the very top of the balloon is what is used to bring the balloon down towards the ground. It is a circle of fabric cut out of the top of the envelop which is controlled by a rope which runs down through the middle of the envelope to the basket. If the pilot wants to bring the balloon down, he or she simply pulls on the rope which will open the valve, letting hot air escape, decreasing the inner air temperature. This cooling of air causes the balloon to slow its rise.

    The pilot can operate horizontally by changing the vertical position of the balloon because the wind blows in different directions at different altitudes. If the pilot wants to move in a particular direction, he or she simply arises and falls to the appropriate level and rides with the wind.

    The ocean bottom, a region nearly 2.5 times greater than the total land area of the earth, is even today largely unexplored. Until about a century ago, the deep ocean floor was completely inaccessible and hidden beneath waters averaging over 3,600 meters deep. Totally without light and in the case of intense pressures hundreds of times greater than at the earth's surface, the deep-ocean bottom is a strange environment to humans, in some way, as fighting and remote as the outer space.

Although researchers have taken samples of deep-ocean rocks for over a century, the first detailed global study of the ocean bottom did not actually start until 1969, with the beginning of the National Science Foundation's Deep Sea Drilling Project(DSDP). Using techniques first developed for the offshore oil and gas industry, the DSDP's drill ship, the Glomar Challenger, was able to maintain a steady position on the ocean's surface and drill very deep waters, taking samples of rocks from the ocean floor.

    The Glomar Challenger completed 96 voyages in a 15-year research program that ended in November 1983. During this time, it sailed 600,000 kilometers and took almost 20,000 samples of rocks around the world. Those samples have allowed geologists to reconstruct what the planet looked like hundreds of millions of years ago and to make out what it will probably look like millions of years in the future. Today, largely on the strength of evidence gathered during the Glomar Challenger's voyages, nearly all earth scientists agree on the theories of plate tectonics (构造学) and continental drift that explain many of the geological processes.

    The sample of rocks drilled by the Glomar Challenger has also provided a climatic record stretching back hundreds of millions of years. The information of past climatic change can be used to predict the future climate.

    Fire fighting is a serious matter. Knowing what to do during a fire can save people's lives. It is important to know the ways you can use and show them to everyone else in the family, such as stairways and emergency exits, but not elevators.

    From the lower floors of buildings, escape through windows is possible. Learn the best way to get out from a window with the least chance of serious injury.

    The second floor window is usually not very high from the ground. An average person, hanging by the fingertips will have a drop of about 6 feet to the ground. It is about the height of an average man. Of course, it is safer to jump a short way down than to stay in a burning building.

    Windows are also useful when you are waiting for help. Be sure to keep the door closed before opening the window. Otherwise, smoke and fire may be drawn into the room. Keep your head low at the window to be sure you get fresh air rather than smoke that may have leaked(漏)into the room.

    On the second or third floor, the best windows for escape are those which open onto a roof. From the roof a person can drop to the ground more safely. Dropping onto cement might end in injury. Bushes and trees can help you to have a soft landing.

    Can dogs and cats live in perfect harmony in the same home? People who are thinking about adopting a dog as a friend for their cats are worried that they will fight. A recent research has found a new recipe of success. According to the study, if the cat is adopted before the dog, and if they are introduced when still young (less than 6 months for cats, a year for dogs), it is highly probable that the two pets will get along swimmingly. Two-thirds of the homes interviewed reported a positive relationship between their cat and dog.

    However, it wasn't all sweetness and light. There was a reported coldness between the cat and dog in 25% of the homes, while aggression and fighting were observed in 10% of the homes. One reason for this is probably that some of their body signals were just opposite. For example, when a cat turns its head away it signals aggression, while a dog doing the same signals submission.

    In homes with cats and dogs living peacefully, researchers observed a surprising behaviour. They are learning how to talk each other's language. It is a surprise that cats can learn how to talk ‘Dog', and dogs can learn how to talk ‘Cat'.

    What's interesting is that both cats and dogs have appeared to develop their intelligence. They can learn how to read each other's body signals, suggesting that the two may have more in common than we previously suspected. Once familiar with each other's presence and body language, cats and dogs can play together, greet each other nose to nose, and enjoy sleeping together on the sofa. They can easily share the same water bowl and in some cases groom (梳理) each other.

    The significance of the research on cats and dogs may go beyond pets ─ to people who don't get along, including neighbors, colleagues at work, and even world superpowers. If cats and dogs can learn to get along, surely people have a good chance.

Accines (疫苗) may soon make their first film appearance. Led by expert Maria A. Croyle, researchers have developed a thin sheet that preserves vaccines for long periods without refrigeration. This means the carefully cooled small bottles now used to ship vaccines could potentially be replaced by lightweight films that can be mailed in an envelope and stored on a shelf.

Croyle's laboratory began developing the technology in 2007. Inspired by amber's ability to preserve the DNA of insects, the researchers set out to create their own version of the substance by mixing "a lot of sugar and a little bit of salt, much like hard candy," Croyle explains. The vaccine-containing film is administered by mouth—sweet news for many who dislike needles.

The film is tailored to suit each specific vaccine candidate and provide a protective coating. "We've learned over time that the key to really stabilizing whatever the film holds is to have it intermixed with all the components," Croyle says, adding that the process is quick and uses affordable, standard equipment. "We really wanted to come up with something that would be transferable to developing countries."

Immunization(免疫) programs depend heavily on keeping vaccines cold(2℃-8℃) as they are transported, sometimes over thousands of kilometers to far-away locations. Delivery can be difficult and costly, and transport disruptions can cause the vaccines to be ineffective.

But this new product can store live viruses, bacteria and antibodies for several months at 20℃. In a paper published in Science Advances, the scientists show that the live viruses in one vaccine were preserved in the film even after 36 months. They also find that a flu vaccine suspended in their film compares favourably with a traditional flu shot(流感预防针). "The study demonstrates early proof of concept for an exciting platform for vaccine product development," says Lisa Rohan, a pharmacologist, who was not involved in the study. She also notes that each vaccine type would need a custom formulation(配方) for future stages of development.

Finding partners to mass-produce for clinical trials is the researchers' most pressing problem, Croyle says. They are also exploring packaging methods to keep their films stable up to 40℃.

Size is a major advantage—a letter-sized sheet of the film can carry more than 500 doses(剂) of vaccine, about 1⁄900 the weight of the same amount of traditional doses. By making it easier and cheaper to ship and preserve vaccines efficiently, Croyle says, the technology could vastly improve immunization rates the world over, particularly in middle- to low- income countries.