When a leafy plant is under attack, it doesn’t sit quietly. Back in 1983, two scientists, Jack Schultz and Ian Baldwin, reported that young maple trees getting bitten by insects send out a particular smell that neighboring plants can get. These chemicals come from the injured parts of the plant and seem to be an alarm. What the plants pump through the air is a mixture of chemicals known as volatile organic compounds, VOCs for short.

Scientists have found that all kinds of plants give out VOCs when being attacked. It’s a plant’s way of crying out. But is anyone listening? Apparently. Because we can watch the neighbours react.

Some plants pump out smelly chemicals to keep insects away. But others do double duty. They pump out perfumes designed to attract different insects who are natural enemies to the attackers. Once they arrive, the tables are turned. The attacker who was lunching now becomes lunch.

In study after study, it appears that these chemical conversations help the neighbors .The damage is usually more serious on the first plant, but the neighbors, relatively speaking, stay safer because they heard the alarm and knew what to do.

Does this mean that plants talk to each other? Scientists don’t know. Maybe the first plant just made a cry of pain or was sending a message to its own branches, and so, in effect, was talking to itself. Perhaps the neighbors just happened to “overhear” the cry. So information was exchanged, but it wasn’t a true, intentional back and forth. Charles Darwin, over 150 years ago, imagined a world far busier, noisier and more intimate (亲密的) than the world we can see and hear. Our senses are weak. There’s a whole lot going on.

Imagine that your friend is cutting the cake to share with all the guests at the birthday party. The first three guests are handed large pieces of cake, while you are handed a teeny-tiny one. How would you feel? Is this fair? Most of us have a clear sense of what is fair and what is not, but where does this come from? Scientists try to study fairness in primate species (灵长类物种) to understand how fairness came about.

Fairness often involves equal outcomes (平等的结果)

Do monkeys behave in ways that lead to equal outcomes? To find out, scientists give monkeys choices about how to share food. Scientists ask a monkey to choose between two options—to provide a piece of food just for themselves, or to provide food for another monkey nearby, as well as for themselves (Figure 1). If monkeys are trying to achieve equal outcomes, they would give food to both themselves and another. Do they? Sometimes.

The left monkey has just chosen the board to give food to himself and the neighboring monkey.	The left monkey has just chosen the board that provides food for himself only.

Whether monkeys favor equal outcomes seems to depend on the species. The species which live in groups will prefer equal outcomes, but not all the time.

What else might be influencing whether monkeys create equal outcomes? If the two monkeys are friends, one is more likely to share food with the other. It also seems that monkeys would make the equal choice when they cannot see the actual food—some scientists use pictures of food.

But wait, does effort matter?

Scientists have developed a way to test whether monkeys prefer everyone to be paid equally for doing the same work. In this study, monkeys are trained to work for food by exchanging small coins with a scientist. To determine if and how monkeys respond to unfairness, scientists have two monkeys take turns exchanging coins and give them different food—their favorite food or a less-preferred food (Figure2). If the monkey getting the less-preferred food refuses to keep exchanging coins, scientists conclude the monkeys respond to unfairness.

The monkey on the left exchanges the coin for a piece of banana. Next, the neighbor monkey will also exchange a coin, but receive a less-preferred piece of food.

The results of the study have suggested differences across monkey species. Generally, monkeys living in groups do not respond to unfairness, while other monkeys do respond to it. However, monkeys do not appear to mind if they get a better food than others.

All in all, monkeys’ sense of fairness does not seem to be as well-developed as our own. By studying their preferences for fairness and responses to unfair situations, we can learn more about how these values developed in humans. And this also helps us to better understand the natural world and how to care for animals as well.

The attendance of accident and emergency department(A&E) is variable. We used to joke that Monday was the busiest day of the week. But some people argued that Sunday, and even Tuesday, were also very busy.

In the business sector, it is well known that Monday has an effect on trading volume: Monday has a lower volume than other weekdays. In the medical field, Watson mentioned that more people had heart attacks on Monday morning — the so-called “Black Monday Syndrome”. In fact, “Monday Syndrome” is variably defined in the literature to mean different things to different people: from occupational disease to increase in injury, etc. When these effects are grouped together and viewed from the macroscopic (宏观的) perspective, it could translate into an increase in demand of the healthcare service on Monday. If it can be shown that this pattern of service demand is reproducible in our local setting, then measures can be taken to redistribute resources to appeal to the uneven demand during the week.

The present study employed existing data obtained from the computer system of the A&E department of a regional hospital with a daily attendance of about 300 per day. The daily attendance from April to June 2010 was grouped in days of the week, in order to find out whether the attendance on Monday was different from the rest of the week. Main measuring variables were the mean (平均的) attendance data of different days of the week. Standard deviation (偏差) and 95% confidence interval (CI) of the means were calculated and compared. Lastly, mean attendance of Monday was compared to that of non-Mondays. Careful inspection of the data showed that Monday was the busiest day of the week (Figure 1) — it had significantly higher attendance than Wednesday, Thursday, Friday, Saturday and Sunday (p<0.05). Monday was also busier than Tuesday, although this is statistically unconvincing.

For Q2 2010, Monday has 12% more attendance than other weekdays. Administrative measures to limit the “predictable” service demand should be taken to avoid overcrowding and long waiting-time on Monday.