Why always clockwise? We all know what's clockwise. Which way the hands of clock swept over its face might not seem to matter. Because no matter it is clockwise or anti-clockwise the time will be told faithfully. In history it is quite an accident decision made arbitrarily. But without doubt it is convenient and efficient. Similarly, this happens to turbine blade manufacturing industry. It is conventional to make wind turbine turn around clock-wisely. But a recent Germany discovery showed that it may not be that simple. The researchers build a computer system to stimulate the air flow get through the wind turbine. They found that in north hemisphere, the turbine blade will generated same power during the day time but at night the power output can be up to 20% higher if the upwind turbine switched anti clockwise.

Why wind turbine turns clockwise is not the most efficient The reason is little bit complicated. By day, the sun heats the earth as well as the air close to the ground. It helps the turbine blade rotor at the same speed and direction at all altitudes when the blade goes up and down. While at night, Coriolis force sheared wind at different altitudes and begets wind veer. In north hemisphere the wind veer turns into a turbulent wake when pass the wind turbine and hampering the wake’s ability to generate more vim on the downwind turbine. And in the southern, it all works the other way around. Thus we don’t need to change anything there. Even the new discovery sounds inspiring, we have to do more investigation to balance the cost of retooling the blade and extra output power squeezed out by doing so. At least, we acknowledged that a lot of apparently natural and conventional decisions made just by tossing a coin.But they still works economically.

Writing on italki platform It's my first time to try to post my writings on italk platform. Fortunately, I found some really good teachers and native speakers coming to correct me. I really appreciate it. I also did the same job for several Chinese learners. It's really intersting and tantalizing. What I learned from the whole process is that maybe we should divide the long writing into small pieces to make it easier to read and correct next time. How do you think of that?

Evolution and gene Feral dog adopt to understand human gestures inate, during the long cohabitated history with man-kinds. The scientists tested free-ranging dogs In experiment, compared with their closed relatives semi-captive wolves(dogs diverged from wolves millions of years ago) feral canines performed pretty better on following the pointing to find food. The data surpassed the random rate. It is convencing that the stray dogs have the innate talent to understand the cue from people. And I believe It's reasonable to suppose that the revelation process coded some ability in our genes to help the whole species to adapt the world better.

Animal intelligence It's well known that a lot of animals can identify the individuals of their species by facial features. On top of that, they can differentiate faces by pictures alone. Well it's easy to perceive that it is a basic ability. Because they need to adjust their behavior to encounter different companions. Ethologist want to advance the research further. They test the horse's ability to recognise the human faces by pictures. The experiment is something like this:they trained the horse to use nose to choose pictures side by side on computer screens then they put the photographs of its current owner alongside someone else the horse never encounter before. The tester found that the horses can choose correctly at a rate much better than chance, saying 70%. What's more, the horse can recognize their former owner as accurately as current one. The Ethologist thought the result shows that the hose have a robust long term memory about human faces compared with our longest co-existed domestic companions-dogs. And the horse know that the photographs are 2-D representations of real life without any other help like odor or sound. All in all from these tests we can easily come to the conclusion that the animals have the same cognitive ability just as we humans do at the primary level. Next time be kind and gentle to our intelligent companions.