【推荐3】Today, some 815 million people suffer chronically（长期地） from hunger. And although this is significantly fewer people than the numbers we saw a decade ago, hunger still kills more people than AIDS, Tuberculosis（肺结核） and Malaria（疟疾） combined.

On May 28th, we observe World Hunger Day. It is an effort to focus attention on the fact that despite an adequate availability of food nearly everywhere, globally, some 21,000 people die every day from hunger or malnutrition（营养不良）.

People do not go hungry because the world does not produce enough food for everyone. According to the world Hunger Education Service, over the past three decades, significant growth in food production, along with improved access to food, helped reduce the percentage of chronically undernourished（营养不良的） people in developing countries from 34 percent to 15 percent. The principal problem is that many people in the world still do not have resources to purchase or grow enough food.

Indeed, hunger is a consequence of poverty, and also one of its causes. Hunger exists because many countries lack social safety nets; because in many countries women, although they do most of the farming, do not have as much access as men to training, credit or land.

Conflict, governance systems that do not encourage investment in agriculture, poor management of land and natural resources, lack of educational opportunity, displacement of small farmers by natural disasters, and financial and economic difficulties that remove jobs at the lowest levels, all contribute toward creating conditions that push the poorest into hunger.

Over the past decade, a global push to reduce hunger and extreme poverty has marked some significant successes, thanks in part to the efforts of numerous international and transnational institutions, foundations, NGOs and governments, including the United States.

But on world Hunger Day, let us not forget that with over 815,000 people still living in daily food insecurity, we still have a long way to go before we can safely say that no child goes to bed hungry most nights and that no parent skimps on（节省） their own dinner so the children can eat.

【推荐2】The demand for digital audio (音频的) books is growing very rapidly. Let’s first look at why this has happened. The busy lifestyle leaves us little time to sit down and read a paper book. Besides, we all have time in the day when we are not really busy mentally. Therefore, we listen and “read” when doing other things.

An audio book, read by a professional narrator who is telling you the story, is an ideal way to “read” books that you wanted to read for long but that lack of time did not permit you to read. Storytelling has a very long tradition and with the new technology, it is gaining popularity again.

“For many people, listening to an audio book is an opportunity to hear an author firsthand,” says Mary Beth Roche, president of the Audio Publishers Association. “It’s like having the very best lecture series, not just in your own town, but in your own car or home — and at your command, they’ll read when YOU are ready to listen.”

Audio books used to be thought of as limited special products for only the blind and sight-impaired (视力受损的) or for kids and lazy people who either can not or do not want to read themselves. This has greatly changed over the last few years. A study found that the average listener of audio books is about 45 years of age and has an average yearly income of over $50,000, and at least a college education and often more advanced degrees. And these people have practical knowledge or understanding of the Internet.

Moreover, audio books are especially good for children who hate to read because of problems in school. That way they are familiar with the adventure of using their own imagination to paint their mental pictures of what they hear, rather than just staring at the TV screen. Also, if they have the book and the audio, reading along can help them overcome reading problems.

【推荐3】A recent study in Frontiers in Sustainable Food Systems shows that tomato fruits are able to transmit alerts to their mother plant when attacked by caterpillars.

Plants have a large number of chemical and hormonal signaling pathways, which are generally transmitted through the sap (树液). Given the facts that fruits just hang from the main plant before ultimately falling off and sap typically only runs from the plant no the fruit—not back and forth between the two—it has long been unclear whether or not fruits can transmit information to the plant.

To address that question, scientists at Brazil’s Federal University of Pelotas placed tomato plants in a Faraday cage. Electrodes (电极) were attached to the ends of the plants’ branches, at the points where they connected to the fruits. Then they measured electrical responses within the branches before, during and after a 24-hour period in which the frits were attacked by caterpillars. Machine-learning-based algorithms were used to identify patterns in the signals.

It was found that there was a “clear difference” between the signals before and after caterpillar attacks. Additionally, defensive biochemical responses were observed throughout the plants’ bodies, suggesting that they had been triggered by signals sent by the fruits. The researchers gave the following explanation. The tomato fruit, sensing a nearby insect, emitted electrical signals to reach the rest of the plant. These warming impulses were received by the main plant and as a result, the rest of the plant got prepared to fight off the unwanted invaders. The tomato fruit made sure that the plant produced chemicals that were unpleasant to taste, so that hungry caterpillars stayed of the fruit.

The scientists now plan on investigating whether other fruiting plants behave in the same manner as tomatoes, and whether their fruits respond to threats other than insects. “It will be possible to detect early signs of pest presence, allowing for less aggressive control measures and more accurate insect management,” explains Niemeyer Reissig, first author of a paper on the study. “Understanding how the plant interacts with its fruits, and the fruits among themselves, may bring insights into bow to ‘manipulate’ this communication for enhancing fruit quality, resistance to pests and shelf life after harvest.”