Q: On Facebook, my friends are a mix of real-life pals, former classmates, professional  colleagues, extended-family members, and...my mom. Mom is the first to like and comment on  everything I post, which is annoying. I tried talking to her about it, but her feelings quickly got  hurt, so I backed off. I know I can’t block her, but now I don’t want to post anything. How do I  handle this? 

A: This is about Facebook, not your mom. The often-shrugged-off truth about social media  is that nothing is private. It’s easy to forget this, so in a way, you’re lucky that your mom is  reminding you. Everything you post—comments, likes, photos—is freely available to future  friends, employers, lovers etc. unless blocked. That said, you can ask Mom again nicely to tone  it down. You can also customize your controls so she can’t see everything you post. 

Q: In which situations am I required to make a phone call versus send a text message? 

A: A text is for information—time, date, news. It’s for the stuff you can keep short and  sweet. A phone call is for analysis, discussion, opinion, and, if you must, gossip. 

Q: I’m always on Facebook, so I just send messages to friends through the site. But when  should I log off and send an e-mail? 

A: When you’re serious about anything. Think of it as chatting with someone on a bus  versus asking her to meet you for coffee. The former is good for casual conversation; the latter  is personal and requires attention. 

Q: For which occasions should I mail paper invitations versus send e-mail ones? (E-cards  are free and easy—what’s not to love?!) 

A: Anything important needs a paper invitation. That’s your baseline. So ask yourself:  “Do I want people to dress up for this event?” If the answer is yes, dress up your invitation by  making it printed instead of virtual. For more casual events and gatherings, e-card away. 

Q: Is using emoticons ever inappropriate to express a feeling or make a point in texts or  e-mails? 

A: Emoticons are for fun. Is the message you’re writing fun? Use an emoticon. Are you  asking for a big favor? Skip it. Is the message to your boss or a colleague? Skip it. Avoid them if you want to be taken seriously about anything. 

Q: I have a big, happy announcement to share with a lot of people. Is it appropriate to share  it on my blog? 

A: Yes, so you don’t have to go cc-ing everyone in an e-mail. Post away. But send a private  message to those who should know first. 

Q: I have a big, sad announcement. What should I do? 

A: Respect your privacy—and yourself. Pick up the phone and call a trusted friend or  family member to let her know, and then ask her to help spread the news offline.

How do you design a pay plan that motivates people to do their best work? A new study  by three Harvard researchers suggests a novel answer: Shortly after you hire new workers, give  them a raise. 

“Previous research has shown that paying people more than they expect may elicit reciprocity（相互作用）in the form of greater productivity,” notes Deepak Malhotra, a Harvard  business-administration professor who worked on the study. What he and his colleagues found,  however, was that the connection between more pay and extra effort depends on presenting the  increase as a “gift”—that is, as something you’ve chosen to do purely as a nice gesture, with no  strings attached. 

Malhotra and his team studied 267 people hired by ODesk, a global online network of  freelancers, to do a one-time data-entry project for four hours. All of the new hires were people  in developing countries, for whom hourly wages of $3 and $4 were higher than what they had  been making in previous jobs. 

The researchers split the group up into three equal parts. One group was told they would  earn $3 an hour. A second group was initially hired at $3 an hour but, before they started  working, they got a surprise: The budget for the project had expanded unexpectedly, they were  told, and they would now be paid $4 an hour. The third group was offered $4 an hour from the  start and given no increase. 

Even though the second and third groups were eventually paid the same amount, the  second group worked harder and produced more—about 20% more—than either of the other  two. People in the second group also showed the most stamina, maintaining their focus all the  way through the assigned task and performing especially well toward the end of the four hours.  Interestingly, the more experienced employees in the high-performing group were the most  productive of all, apparently because their previous work experience led them to appreciate the  rarity of an unexpected raise. 

Contrary to conventional wisdom, Malhotra points out that higher pay, in and of itself,  didn’t promote productivity: People who made $4 an hour from the beginning worked no harder  than those who were hired at $3 and were then paid $3. 

To get the most impact from their pay plans, he adds, companies might consider not only  what to pay new hires, but when to pay it. 

“The key thing is how you present,” he says. Doling out extra money could promote  productivity most. “If you make it clear that the pay raise is something you’re choosing to  do just because you can. Our theory is that people will reciprocate. If you do something nice,  they’ll do something nice back.”  

For decades, public health officials have puzzled over a surprising fact about HIV: Only about 10-20 percent of infants who are breastfed by infected mothers catch the virus. Tests show, though, that HIV is indeed present in breast milk, so these children are exposed to the virus multiple times daily for the first several months of their lives.

Now, a group of scientists and doctors from Duke University has figured out why these babies don’t get infected. Human breast milk naturally contains a protein called Tenascin C that neutralizes HIV and, in most cases, prevents it from being passed from mother to child. Eventually, they say, the protein could potentially be valuable as an HIV-fighting tool for both infants and adults that are either HIV-positive or at risk of contracting the infection.

The research, published in Proceedings of the National Academy of Sciences, was inspired by previous work by other researchers showing that, both in tissue cultures ( 组织培养 ) and live mice, breast milk from HIV-negative mothers was naturally endowed with HIV-fighting properties. Scientists suggested that a few different proteins in the milk could potentially be responsible, but no one knew which one.

As part of the study, the researchers divided breast milk into smaller fractions made up of specific proteins via a number of filters—separating the proteins by size, electrical charge and other characteristics—and tested which of these fractions, when added to a tissue culture, prevented the cells from being infected by HIV. Eventually, they found that one particular protein was present in all the HIV-resistant fractions but in none of the others: Tenascin C.

Tenascin C works by blocking a key protein on HIV’s envelope that normally ties up to a receptor on a T cell’s membrane called CCR5. In doing so, Tenascin C prevents HIV from mixing with the T cell and injecting its RNA inside. Still, the researchers say that other natural elements in milk might play a role in fighting HIV as well. “It’s clearly not the whole story, because we do have samples that have low amounts of this protein but still have HIV- neutralizing activity,” the study’s lead author Permar says. “So it may be acting in concert with other antiviral and antimicrobial factors in the milk.”

Whatever those other factors are, though, the finding vindicates recent changes to UN guidelines that recommend even HIV-positive mothers in resource-poor countries should breastfeed, if they’re taking anti-retroviral drugs to combat their own infection.

The next steps, Permar says, are determining which area of Tenascin C is active and whether it can effectively prevent transmission in a live animal. If it works, it could potentially be incorporated into an HIV drug with broader applications. It’s even possible that it could someday be adapted to reduce the risk of HIV transmission in adults as well as infants.

The lights go out—another power failure. “Get the candles,” Mom says, and I do. My younger brother and I search every room to collect the tall candles and votives ( 烛台 ) spaced around the house. I hurry from shelf to shelf gathering  wax ( 蜡 ) sticks in my arms and place them in the living room, a few candles in each corner except for a small red votive. That one I keep. It is the one I will take to the coffee table to use to read. I slide my book, Things Fall Apart, beside the candle holder, determined to finish the last three chapters, but lacking determination. So the book remains closed. A sigh escapes my brother’s lips.

“This is boring,” he says. A drop of wax falls on my book. “I know,” I say, but really, I am enjoying the stillness. I like to watch the candle burn and feel that life is simple. I like to look out of the window into an immediate darkness unspoiled by unpleasant light. I love these silent moments when I feel as if I can live the way they lived, the people of the past—the Egyptians, the Pilgrims （朝圣者）, the Greeks—anyone who ever lived to see the black color I’m seeing, anyone who lived to see a yellow flame and depended on it. I feel at once with a secret, ancient age. I’m convinced that night, in this disturbed state, is the closest a person can get to experiencing the past.

So, what was night really like for them? Night, as we know it now, is a pleasant, loving thing compared to the incomprehensible darkness that covered Earth’s first people. Even its beauty seemed unmatched.

What did a farmer’s family do at night? Of course, the darkness must have brought them together, forced them into each other’s company as it has done to us tonight—developed a close relationship in a time of fear and uncertainty. A fire probably burnt brightly in a central room where the family gathered to talk and relax. Night was a time when men and women were liberated from work and socialized. They had no computers or TVs, and had to make do with books, religion, and conversation. At their bedside, they prayed to God, and felt a sense of security that they were out of the darkness and harm’s reach.

Nevertheless, to run a risk of going outside was sometimes necessary, and the threat of robbers, wolves, even the ethereal ( 太空精灵 ), was present. What emotions did these people feel? Did they witness a deep bright blue cloud across heaven? What would it have been like to feel the night, heavy and damp against my back? Would it have taken me, choked me with its powerful hands, separated me from other people? Or would those have been awful dreams, and dreams only?

I imagine a young girl, stepping outside her home and into a desert for some air. A cool, earthy smell would greet her. There’ s a sky with millions of stars—far more than a person could see today—and there’s the moon. It’s the largest object in the sky, the midnight sun that shines in the world, the traveler’s torch. It inspires stories of uncertainty, stories of power. I imagine this girl amazed at the moon and stars. If she wanders too far, she needn’t worry, for the stars will lead her back home.

Bzz! The lights return. Everyone cheers and abandons the room, happy that their period of being lonely is over, everyone except me. I pull my candle closer, and stare into the night. The glory is gone; it has been made less bright by street lamps, electric signs, TVs, and all other manners of artificial light. But in those moments, when every light in every house was off， people may have had a taste of the old world. They may finally have touched upon the slight fear, the admiration, and the respect that our ancestors felt for the night.