2 . School Activities for Kids and Teens

July is a month of fun-filled activities for kids and teens as long as you know where to find them. When you want some fun activities for July, consider these ideas happening this month.

3 . The Last Greatest Magician in the World

In this book, we can learn about the wonderworker Howard Thurston. During his life, Thurston successfully made changes in entertainment. His magic show is regarded as the one that inspires our memories.

Author: Jim Stein Meyer Length: 384 pages Publication Date: Feb. 3, 2011

Beholders: A World Without Heroes

Jason Walker lives a peaceful life until one day he falls through a hole and ends up in a new foreign world. In Lydian, the people dress and behave differently, living in fear of their Emperor Surratt. But during Jason’s search for a way home, he learns of a magical word that could kill Surratt and becomes the hero he has never imagined.

Author: Brandon Mull Length: 464 pages Publication Date: Feb. 15, 2011

Life

With his honesty, Keith Richards brings us the story of a life we all have longed to know more of. Its hard to imagine a famous persons biography is as easy to drink in as Keith Richards life. The books content agrees with the rhythm of his voice so much that reading his tale is like sharing a cup of beer with an old friend.

Author: Keith Richards Length: 576 pages Publication Date: Oct. 26, 2010

The Monkey and the Monk

The famous translation of The Journey to the West is popular with English-speaking audiences. The book shows the novels most exciting and meaningful parts without taking anything away from their true spirit. Moreover, with a new form, this translation is sure to attract more fans.

Author: Anthony C. Yu Length: 528 pages Publication Date: Nov. 15, 2006

4 . The world’s craziest festivals

Crazy festivals all over the world are out there just waiting to be celebrated. Join Cornelia Kumfert on a trip to the most unusual events taking place around the globe.

Burning Man Festival

Every year in Nevada (US) there is artwork and cunosities galore to marvel at when the Black Rock Desert changes into a mammoth art exhibition.

In August and September, some 70,00 people come here to celetrate the Burning Man Festival.

San Diego Comic Con

Surely superheroes don’t queue? Well, at San Diego’s Comic Convention they do. Each July hey open their dos to fans of Superman and other comic figures. More than 100,000 annual visitors have paid homage to their mythical heroes.

Crying Baby Festival, Tokyo

At the Crying Baby Festival in Tokyo (Japan), sumo wrestlers do what they can to bring babies to tears.

Sadists run riot? Certainly not! It’s a 400-year-old tradition based on a Japanese proverb, which says that crying babies grow fastest and parents believe the event brings good health to their children.

Palio Contest, Siena

Fame and honour await the winner of the Palio contest in Siena (Italy).

In July and August, ten inhabitants of different districts of the city jockey for first place in a spectacular horse race.

The trophy goes to the contestant whose horse crosses the finishing line first—whether he’s still in the saddle or not.

5 . An augmented-reality (增强现实的) helmet that gives cyclists a 360-degree view of the road could help prevent accidents.

Unlike cars, bicycles don't come with rear view mirrors (后视镜), which is why British product design firm DCA created the Optic helmet. The helmet has front and rear cameras and a drop-down visor (面罩) that can display road conditions in real-time from the rear camera onto a rider's field of view. The visor can show warnings. If a vehicle is overtaking (超过) the rider, it can warn the rider by combining data from the cameras on the front and back of the helmet. In addition, the Optic helmet can provide GPS navigation information for riders who want to track their performance. The design is now just a concept, but it won the “Best of the Best” Red Dot Design Award recently.

Richard Price, a designer at DCA and the brains behind the project, said the helmet is aimed at reducing cycling accidents. Because the helmet is just a concept design, some of the details have yet to be decided, such as the exact method for projecting video onto the visor. However, Price said Google Glass has already shown that this is practical. The Optic helmet will be able to connect to a smartphone via Bluetooth to allow maps and routing information to be updated, but actual navigation will be carried out by the helmet using its onboard (自身携带的) GPS unit. It can be controlled either by a touchpad next to the visor or by using gestures picked up by the front camera.

“Users can order what is shown in the visor to suit their needs and to make sure the display doesn't distract them.” Price said. Since the designs were made public, Price said the design firm has received plenty of positive feedback from cyclists and cycling companies. But actually, putting the device into production will require lots of money, so it is unclear when or if the helmet will be available to consumers.

6 . Database maintenance (数据库维护) is an activity designed to keep a database running smoothly. A number of different systems can be used to build and maintain databases. Databases are used to maintain a library of information in a well-organized, accessible format (格 式).They usually are not static (静态的),because changes are constantly being made as material is added, removed, and moved around. Over time, this can cause the database to start to go wrong. Database maintenance is used to keep the database clean and well-organized so that it will not lose functionality.

One important aspect of maintaining a database is simply backing up the data so that, if anything happens, there will be another copy available. Some database systems actually do this automatically and then send the backup to another location every day, every week, or within any other set period of time. Backups are usually not enough, however.

Database maintenance includes checking for signs of corruption in the database, looking for problem areas, and checking for any detail in the database that might signal a problem. The goal is to keep the database operating smoothly for users, so that ideally they never need to think about maintenance issues. A database that is not maintained can become slow, and people may start to experience problems when trying to access records.

The maintenance of databases is generally performed by people who are comfortable and familiar with the database system and the details of the particular database, although some maintenance tasks can be performed by people who do not have experience. Numerous textbooks are available with information about database management, including how to maintain databases properly. It is also possible to take courses to learn about different database systems and how to care for databases. People can also earn certifications in specific systems which indicate a high level of competence.

7 . The best science fiction books of 2021

We take a look at the most exciting new science-fiction books of 2021. No matter what kind of science fiction fan you are, we're sure you'll find something to add to your reading list.

The Saints of Salvation

By Peter F. Hamilton

The Olyix have laid siege（围攻）to Earth, harvesting people for their god. Cities are ru¬ined by their weapons and millions have either fled to seek refuge in space or are fighting a war that seems unwinnable. As Earth's defeat draws ever closer, a team are sent to enter the Olyix's air-ship secretly. Their plan? This is the final science fiction in Peter F. Hamilton's extremely surprising series The Salvation Sequence.

A Desolation Called Peace

By Arkady Martine

This impressive sequel（续集）to Arkady Martinets Hugo Award-winning science fiction book sees the Teixcalaanli Empire facing an alien threat which could bring about its complete destruction. Fleet captain Nine Hibiscus sends a person to negotiate with the mysterious invaders...

Jack Four

By Neal Asher

Jack Four-one of twenty human clones-has been created to be sold. His purchasers are the aliens and they only want him for their experimentation program. But there is something different about Jack. No clone should possess the knowledge that's been loaded into his mind.

Rabbits

By Terry Miles

Rabbits is a secret, dangerous and sometimes deadly underground game. The rewards for winning are unclear, but there are rumors of money or it might unlock the universe's greatest secrets. Everyone knows that the deeper you get, the more deadly the game becomes-and the body count is rising. Since the game first started, ten rounds have taken place. The eleventh round is about to begin, and what happens in the game, stays in the game...

10 . As of 2020, the world's biggest lithium-ion (锂离子) battery is hooked up to the Southern California power grid and can provide 250 million watts of power, or enough to power about 250,000 homes. But it's actually not the biggest battery in the world: these lakes are.

Wait - how can a pair of lakes be a battery? To answer that question, it helps to define a battery: it's simply something that stores energy and releases it on demand. The lithium-ion batteries that power our phones, laptops, and cars are just one type. They store energy in lithium ions.

How do the two lakes store and release energy? First, one is 300 meters higher than the other. Electricity power pumps that move billions of liters of water from the lower lake to the higher one. This stores the energy by giving the water extra gravitational potential energy. Then, when there's high demand for electricity, valves (阀门) open, releasing the stored energy by letting water flow downhill to power 6 giant turbines that can generate 3 billion watts of power for 10 hours.

Unfortunately, neither of the giant batteries we've talked about so far is big enough to power multiple cities. The two lakes setup requires specific geography, takes up a lot of land, and has high upfront costs to build. The giant lithium-ion battery in California can power about 250,000 homes, yes, but only for an hour. Lithium-ion batteries also require certain heavy metals to make. These resources are limited, and mining them causes environmental damage. Inventors all over the world are rising to the challenge of making batteries that can meet our needs - many of them even weirder than the two lakes.