sciencetriffic

SAD (seasonal affective disorder) and 'winter blues'

Animals react to the changing seasons with changes in mood, metabolism and behaviour and human beings are just the same. Many people find they eat and sleep slightly more in winter and dislike the dark mornings and short days and this is commonly referred to as 'winter blues'. For some, however, symptoms are severe enough to disrupt their lives and to cause considerable distress. These people are suffering from SAD.

How does SAD affect people?

Symptoms tend to start from around September each year lasting until April, but are at their worst in the darkest months. Symptoms include:

• Sleep problems - oversleeping but not refreshed, cannot get out of bed, needing a nap in the afternoon
• Overeating - carbohydrate craving leading to weight gain
• Depression, despair, misery, guilt, anxiety - normal tasks become frustratingly difficult
• Family / social problems - avoiding company, irritability, loss of libido, loss of feeling
• Lethargy - too tired to cope, everything an effort
• Physical symptoms - often joint pain or stomach problems, lowered resistance to infection
• Behavioural problems - especially in young people

Who does it affect?

The standard figure says that around 2% of people in Northern Europe suffer badly, with many more (10%) putting up with milder symptoms (sub-syndromal SAD or winter blues). Across the world the incidence increases with distance from the equator, except where there is snow on the ground, when it becomes less common. More women than men are diagnosed as having SAD. Children and adolescents are also vulnerable.

What causes it?

The problem stems from the lack of bright light in winter. Researchers have proved that bright light makes a difference to the brain chemistry but why some people suffer and others don't is not clear.

Nerve centres in our brain controlling our daily rhythms and moods are stimulated by the amount of light entering the eyes. As night falls, the pineal gland starts to produce a substance called melatonin that tells our body clock it's night time; bright light at daybreak is the signal for the gland to stop producing this melatonin. But on dull winter days, especially indoors, not enough light is received to trigger this waking up process.Light is also linked to serotonin (also known as or 5HT), a neurotransmitter in the brain. This makes sense because low serotonin levels can cause depression and if you're depressed it can be difficult to concentrate and complete what would normally be simple tasks. Evidence has shown that serotonin levels increase with exposure to bright light - SSRI drugs such as Prozac have the same effect.

What treatment is there?

As the cause is lack of bright light, the treatment is to be in bright light every day. Going to a brightly-lit climate, whether that's skiing or somewhere hot, will relieve symptoms but if that's not possible you can use a bright light. The preferred level of light is about as bright as a spring morning on a clear day and for most people sitting in front of a light like this for around 30 minutes a day will be sufficient to alleviate the symptoms. You don't have to stare at the light, so you can watch TV or read or similar, just make sure that light reaches your eyes.

The light must be suitably bright. You need at least 2500lux (lux is the technical measure of brightness) which is roughly five times brighter than a well-lit office. Brighter 10,000lux lights take less time to use and allow you to sit further away. Simply using 'daylight' or 'full spectrum' lights at home will not work as they're not bright enough.

See all products for SAD including lightboxes, LED lights, desklamps and Bodyclock dawn simulators >

We encourage SAD sufferers to seek the support of their doctor. We can also supply comprehensive information packs for medical practitioners.

Please see your doctor if you believe you may be suffering from a depressive illness.

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Women's tears contain chemicals that dampen amorous feelings in men, suggests an Israeli study.

The sniff tests of tears, released Thursday by the journal Science, opens a new avenue for study of the role of "chemosignals" sent by sense of smell.

"Women may influence men by chemosignals, in addition to and not in place of spoken language, facial expressions or body language," says study co-author Sagit Shushan of the Weizmann Institute of Science in Rehovot. "It's not a manipulation, but rather a physiological reaction."

The study team led by Weizmann's Shani Gelstein collected tears from women watching an excerpt of the tearjerker movie, The Champ. Conducted over three years, the team tested tears from 12 women on more than 100 men in 114 sniff test experiments, where the men uniformly reported no discernible scent to the tears.

Nevertheless, compared to plain old salt water, tests with the tears induced a statistically significant drop in testosterone and other measures of sexual interest, such as pulse, in men looking at pictures of attractive women, and watching variously, sad, erotic or "neutral" (nature documentaries) film excerpts. Brain scans also show decreased activity in regions of the brain linked to arousal in men sniffing tears, as opposed to salt water dribbled over women's cheeks.

The researchers didn't try to draw any conclusions about why nature would create chemicals with this kind of effect. But, "this is a very well-controlled experiment that opens the floodgates to all sorts of scientific questions," says behavioral neuroscientist Charles Wysocki of the Monell Chemical Senses Center in Philadelphia, who was not part of the study.

In the last decade, T-shirt-sniffing studies have shown women more attracted to smells of men with different immune system chemistry, he notes, but the tears finding opens a new avenue for chemical signaling between the sexes, he says. Other T-shirt studies have shown women prefer the smell of their boyfriend's sweat.

"We are a visual species, humans are visual beings, the visual impact of seeing someone crying is going to wipe over whatever chemical effects are found in tears," says neuroscientist Thomas Mast of Florida State University in Tallahassee. "But I do think this is very cool, a good first step that needs to be repeated, and investigated."

The "most surprising outcome" was finding tears had an effect on sexual arousal, but not measures of empathy or mood, Shushan says. Inspiration for the study came from a finding of chemosignals in the tears of mice. The study team speculates that men's tears, and perhaps children's, tears, may also contain chemosignals, and hopes to conduct similar studies on them. Shushan says the team has still not concluded which chemical in tears produces the dampening effect.

"These intriguing findings hint at just how much we still have to learn about how the social world influences us, how it becomes quite literally incorporated" into the chemistry of our makeup, says psychologist Cordelia Fine, author of Delusions of Gender: How our Minds, Society, and Neurosexism Create Difference. "We tend to think of hormones as driving us to think, feel and act in particular ways, and this study is a nice reminder that the relationship between hormones, brain, and behavior isn't a one-way street."

By Dan Vergano

One man's plan for free Internet for the world, via satellite

Kosta Grammatis, CEO and founder of ahumanright.org, sees having an Internet connection as a basic human right. Grammatis is raising $150,000 to buy an orbiting satellite from a bankrupt company. He's looking for donors and partners.

By Jeremy Hsu, Senior writer, Space.com / December 22, 2010

One man's bankrupt satellite company is another man's opportunity to spread free Internet across the world. That's the hope of Kosta Grammatis, CEO and founder of ahumanright.org, who sees having an Internet connection as a basic necessity — in fact, a human right — for every global citizen.

TerreStar-1 is a high-power commercial satellite shown here in the Space Systems/Loral manufacturing facility in Palo Alto, Calif., before being launched into orbit. The satellite is for sale now.

Grammatis is raising $150,000 to create a business plan for buying a communications satellite and moving it to a new orbital slot to provide free Internet service to developing countries. He has his sights set on the TerreStar-1 satellite: a spacecraft the size of a school bus that launched in 2009 and is owned by a company that filed for Chapter 11 bankruptcy protection in October.

The idea of making free Internet available to all may sound like a pipe dream, but Grammatis has the right combination of technical background and ambition for the job. His resume includes working as an engineer for private spaceflight company SpaceX, as well as creating a bionic eye camera to transform a one-eyed filmmaker into "Eyeborg."

Top 10 Countries that say Internet access is a basic right

Grammatis and his team plan to pay the bills by allowing telecommunications companies to buy and resell high-speed bandwidth, even as they provide a slower connection speed for free to everyone. They have also begun to develop an open-source, low-cost modem that could provide developing countries with their link to the satellite and the rest of the world.

To achieve this dream, ahumanright.org launched a "Buy This Satellite" initiative on a new website.

Q: SPACE.com: What are the basic goals of ahumanright.org?

Grammatis: ahumanright is charged with promoting Internet access as a human right. The organization also promotes endeavors that can ensure everyone has a chance to get online. We try to do this in three different ways:

• Connect with businesses and governments and discuss the creation of a "free" segment to their networks
• We have been envisioning our own free network with our friends at NASA and other industry experts
• We attempt to buy and re-purpose underutilized infrastructure to bring free Internet to the people

SPACE.com: How much geographical coverage can TerreStar-1 provide in terms of Internet? Could it provide service to all of Africa?

Grammatis: Currently it can cover all of America, southern Canada and northern Mexico. Not entirely Africa.

SPACE.com: What considerations are going into the choice of where to park the satellite? How will you weigh public or donor opinions?

Grammatis: That is a very complicated question that has no simple answer.

SPACE.com: How much do you envision the open-source, low-cost modem might cost?

Grammatis: We're aiming for less than $100, but that's dependent on a lot of factors.

SPACE.com: Do you have any business partners or larger-scale funders in mind?

Grammatis: Plenty. Google comes to mind first, Richard Branson second. People and organizations who like taking big risks and doing things that have a lot of positive impact.

SPACE.com: Are there any possible plans to repeat this process for other satellites, if this ultimately proves successful?

Grammatis: Already in the works! We've got another collaboration coming together that should be announced soon if things go as planned.