Posted in social, technology

Digital doctor: the computer will see you now

Just as people display their emotions through body language and behaviour, your emotional state can now be detected using your Instagram account.

Researchers at the University of Vermont and Harvard University have shown that machine learning algorithms can successfully detect depression from Instagram photos. Currently, the computerised method has a success rate of 70%, a vast improvement on the 42% achieved by general practice doctors diagnosing in-person.

The computerised method has a success rate of 70%

In order to collect the data, the scientists recruited 166 volunteers from Amazon’s Mechanical Turk, half of whom had reported having clinical depression in the last three years. Using well-established psychology research, their Instagram feeds were analysed for signs of depression, including brightness, colour and shading preferences. Pixel analysis of the dataset showed that depressed individuals tended to post bluer, darker and greyer photos than their healthier colleagues. From Instagram’s pre-set filters, it was found that the black-and-white ‘Inkwell’ was the most popular among depressed people. On the other hand, healthy individuals seemed to favour warmer filters such as ‘Valencia’.

Along with colours, the amount of faces shown in photos could also be used to indicate depression. Although depressed people were more likely to post a photo including a face, their photos had, on average, fewer people within the shot. “Fewer faces may be an oblique indicator that depressed users interact in smaller settings,” says Chris Danforth, a professor at the University of Vermont. This is corroborated by previous research linking depression to less social interaction. Or, it indicate that depressed people take more ‘selfies’. However, according to Danforth, this ‘sad-selfie’ hypothesis remains untested.

“So much is encoded in our digital footprint,”

“So much is encoded in our digital footprint,” Danforth explains. “Clever artificial intelligence will be able to find signals, especially for mental illnesses.” It is certainly true that this new technique has potential, especially in terms of early onset diagnoses, avoiding false diagnoses and reducing the cost of mental health screening. However, it is still in its early stages. “This study is not yet a diagnostic test, not by a long shot,” says Danforth. “But it is a proof of concept of a new way to help people.”

Tabitha Watson

Image Credit: [http://www.sonypark360.net/wp-content/uploads/2016/11/2016-11-11-image-8.jpg]

Posted in biology, physics, technology

Humans vs Neanderthals – the mammoth competition that ended in extinction

After thousands of years, the reason for the Neanderthal’s extinction has finally come to light. Using isotopic analysis, it was found that both ancient humans and the Neanderthals were in direct competition for their main food source – woolly mammoths.

The first anatomically modern humans are thought to have colonised Europe around 43,000 years ago, forcing the Neanderthals into extinction approximately 3,000 years later. So, why did Homo sapiens succeed where the Neanderthals could not? There are many hypotheses, but by far the most common is that the diet of anatomically modern humans was more varied and flexible, allowing them to consume fish. However, a new study by the Senckenberg Research Institute and the Natural History Museum has blown this out of the water.

The hypothesis that early humans had a more varied diet has been fuelled by the observation that they had a higher abundance of 15N in their bone collagen when compared with Neanderthals. This difference was chalked up to the addition of freshwater fish to the diet, a conclusion that has been refuted by  Prof. Dr. Hervé Bocherens and his colleagues at the University of Tübingen.

There are two main explanations for the presence of 15N in ancient human remains – a high concentration of 15N in the natural environment, especially concentrated in the meat of large herbivores whose meat makes up the majority of the diet, or a significant dietary contribution from a single prey with higher 15N abundance than prey usually found at archaeological sites (e.g. fish or mammoth meat).

Until recently, it has not been possible to distinguish between the dietary impact of freshwater fish and mammoth as both are known to have high 15N abundance and comparable levels of the 13C isotope. Due to the overlapping isotope abundances, accurate estimation from collagen alone was not possible. However, due to recent advances in stable nitrogen isotope analysis on individual amino acids, it is possible to identify the exact origin of the proteins consumed by the ancient humans.

In the study, the remains of three anatomically modern humans were examined. Found in the Belogorsk region of south Crimea, the remains were examined for phenylalanine (as a baseline) and glutamic acid (as an indicator of trophic position). Alongside the humans, the fossils of variety of prey animals found during the excavation were also investigated. Using the percentage ratio of the 13C to 15N isotopes present in the proteins of both the ancient humans and their prey, the scientists could establish the main components of their diet. Using this data, it was found that mammoth meat made up around 40-50% of the Homo sapiens’ diet. Isotopic studies of western European Neanderthals have also pointed to a significant consumption of mammoth meat, placing them in direct competition with the ancient humans.

This fierce interspecies competition for resources placed the Neanderthals under extreme stress. Without unrivalled access to their main food source – woolly mammoths – they were unable to forage enough food to survive. Whether due to superior hunting ability, increased brain size or other factors, Homo sapiens emerged on top. Without competition, humans thrived and have persisted until today. However, this is not the case for the poor woolly mammoths.

Tabitha Watson

Image Credit: [http://www.nhm.ac.uk/content/dam/nhmwww/our-science/news/2014/mammoth-model-753.jpg]

Posted in social

Mind the gap: will it ruin your marriage?

According to researchers at the University of Colorado Boulder, similarly-aged spouses tend to have happier marriages.

Since 2001, data from 7,682 Australian households has been collected using the Household, Income and Labour Dynamics in Australia (HILDA) survey. Due to the length of the study and the sheer number of participants, data analysis has unearthed several distinct trends in marriage satisfaction over time.

As is somewhat expected, one of the initial findings was that men who are married to younger wives are generally the most satisfied – at least initially – and those married to older women are usually the least satisfied. Women are also particularly dissatisfied when married to an older husband and satisfied when married to a younger spouse. Indeed, the dice seem weighted in the favour of the elder spouse – no matter the gender.

However, according to the data, the initial satisfaction of having a younger spouse tends to wane after ambling along for six to ten years of marriage. “Over time, the people who are married to a much older or younger spouse tend to have larger declines in marital satisfaction over time compared to those who are married to spouses who are similar in age,” says Terra McKinnish, a professor of economics at the University of Colorado Boulder.

When the data was analysed, special attention was paid to when couples experienced financial shocks. “We found that when couples have a large age difference, they tend to have a much larger decline in marital satisfaction when faced with an economic shock than couples that have a very small age difference,” noted McKinnish.

One of the proposed reasons for this decline in contentment is the fact that similarly-aged couples are more likely to be more ‘in-sync’ in terms of life decisions that affect both partners, such as having children or purchasing a house. Converse to this, it could be that any differences in opinion within a relationship with a large age gap could potentially be exposed in the event of a financial shake-up, resulting in a conflict of opinion.

Obviously, there are exceptions. Indeed, many couples have successfully bucked the trend. Brigitte, the wife of Emmanuel Macron the current President of France, is twenty-five years his senior, and the age gap between Donald Trump, US President, and his wife Melania is also twenty-five years.

Tabitha Watson

Image Credit: [http://s.newsweek.com/sites/www.newsweek.com/files/2017/07/13/brigitte-emmanuel-macron-donald-melania-trump.jpg]

Posted in biology

Could yoga be used to treat depression?

A series of studies into the antidepressant effects of yoga have returned positive results.

Since its rise to western popularity in the 1980s, people have enthused about the health benefits of yoga. One of the most frequently touted claims is that practicing yoga can aid your mental health. However, empirical evidence to back up these claims has often been difficult to find.

Lindsey Hopkins, a researcher at the San Francisco Veterans Affairs Medical Centre, has set out to plug the gap. Her study focusses on the antidepressant effects of hatha yoga, a branch of the discipline that emphasises physical exercise, meditation and breathing exercises in order to enhance wellbeing. Twenty-three male veterans participated in the study, attending twice-weekly classes for eight weeks. The result? All the participants with elevated depression scores before the program experienced a significant decrease in symptoms after their involvement.

Nina Vollbehr, who works at the Centre for Integrative Psychiatry in the Netherlands, has also investigated yoga’s antidepressant potential. Her first study involved tracking twelve patients, each of whom had experienced depression for an average of eleven years, as they participated in nine weekly yoga sessions. The participants’ levels of depression, anxiety, stress, rumination and worry were measured before they took part, immediately after the program and then again four months after the program ended. The data collected showed a decline in the symptoms of anxiety, stress and depression throughout the program, the benefit of which persisted for the four months afterwards. On the other hand, rumination and worry did not decrease during the program. However, a slight reduction in rumination and worry symptoms was found in the four month follow up.

Vollbehr’s second study compared yoga to another relaxation technique. In it, seventy-four mildly depressed university students were given thirty minutes of instruction on either yoga or relaxation. They were then asked to perform the same exercises at home for eight days, with the aid of a video. Immediately after the study, it appeared that both yoga and relaxation both had the same positive effect, but the two month follow up indicated that the yoga group had significantly lower scores for depression, anxiety and stress than those who had followed the alternative relaxation program.

Now, it is clear that the sample sizes in the studies are small and that the research into yoga as a treatment for depression is still very much in its preliminary stages. However, according to Jacob Hyde, a military psychologist at the University of Denver, the concept of yoga as a complementary or alternative mental health treatment certainly seems promising.

Tabitha Watson

Image Credit: [http://hhpblog.s3.amazonaws.com/blog/wordpress/wp-content/uploads/2015/12/rolled-up-yoga-mats-exercise.jpg]

Posted in chemistry

Another layer of onion chemistry has been peeled away

After 150 years, the structure of the enzyme responsible onion’s eye irritation has been found.

It’s common knowledge that cutting onions can make you cry. Upon damage to the plant tissue, onions release a compound called lachrymatory factor (LF) as a chemical defence mechanism, irritating the eyes and causing them to water. What is less well known is the mechanism the onions use in order to generate the chemical. In fact, scientists have been stumped for over 150 years.

Despite the knowledge that LF is produced by a reaction catalysed by the enzyme lachrymatory factor synthase (LFS), analysing the conversion of the initial substrate – usually a sulfenic acid – to LF has been difficult to achieve. Unfortunately, the rapid reactivity of the substrate and the instability of the LF makes them very challenging to observe.

In order to surmount this problem, a team of US researchers determined the crystal structure of LFS. By analysing the crystal structure, they were able to observe the structure of the enzyme both as a whole and as its active site bound to another compound. Using this data in conjunction with known information about similar proteins, they were able to deduce the chemical mechanism used in the enzyme catalysed reaction – a sequential proton transfer accompanied by the formation of a carbocation intermediate (as illustrated in Figure 1).

mechanism

Figure 1

Tabitha Watson

 

The paper, entitled ‘Enzyme that makes you cry – crystal structure of lachrymatory factor synthase from Allium cepa‘ can be found in the journal ACS Chemical Biology [DOI: 10.1021/acschembio.7b00336]

Posted in science

Is pet food costing the Earth?

Have you ever wondered about your cat’s carbon footprint?

According to researchers at UCLA, meat eaten by cats and dogs in the US creates the equivalent of 64 million tons of carbon dioxide per year – the same climate impact as a year’s worth of driving from 13.6 million cars.

Livestock production required to meet overall US demand produces, on average, the equivalent of 260 million tons of carbon dioxide per year. Of this, between 25 to 30% can be chalked up to the meaty diet of cats and dogs. Currently, our fluffy friends consume around 25% of the animal-derived calories in the US. Incredibly, if the 163 million cats and dogs currently residing in America were to create their own furry country, they would rank fifth in global meat consumption.

Despite having the most pets per capita, this is not just an American issue. As of 2014, it was estimated that 24% of the UK’s population owned a dog and 18% owned a cat – percentages that are echoed by the majority of developed countries. Along with this, as emerging countries such as Brazil and China become more affluent, more people are purchasing pets.

Now, this isn’t to say that we should put our pets on a vegetarian diet. Indeed, doing this would be harmful and unhealthy for them. Getting rid of pets isn’t really an option either. Growing numbers of people consider their pets to be more like family members than animals, and it’s indisputable that pets provide both friendship and a wide variety of other social, health and emotional benefits.

So, how do we solve the problem?

Although the pet food industry is beginning to take steps towards greater sustainability, it will take a while to get there. In the meantime, you could consider getting a vegetarian pet such as a bird, hamster or rabbit in order to cut your carbon footprint.

Of course, if small animals aren’t really your cup of tea, you could always take Professor Gregory Okin’s advice and purchase a tiny horse. As he points out, ‘we’d all get more exercise taking them for walks, and they would also mow the lawn.’

Tabitha Watson

Posted in general, science, technology

Not feeling your selfie?

In a rather Black Mirror turn of events, researchers at the University of Waterloo have developed an app that will tell you how to take ‘the perfect selfie’.

To help you capture your best angle, the app uses an algorithm to direct the way you position the camera.

In order to decide on the ‘best’ angle, the researchers used 3D digital scans of a collection of computer generated people. Then, after taking hundreds of virtual selfies – each with different composition and lighting, an online crowdsourcing service was used to get thousands of people to rate the selfies as either ‘good’ or ‘bad’. These voting patterns were then mathematically modelled in order to develop the algorithm.

To check that the app worked as it should, the researchers had real people take selfies with and without the computerised aid. Based on the subsequent online ratings, a 26% improvement was seen in selfies taken with the app compared to a normal phone camera.

‘We can expand the potential to include variable aspects such as hairstyle, types of smile or even the outfit you wear,’ says Dan Vogel, one of the scientists involved in the development of the app.

Tabitha Watson

To see the app in action, click here.

Image credit: [http://images.shape.mdpcdn.com/sites/shape.com/files/styles/story_detail/public/selfie-study-promo.jpg]

Posted in chemistry, science

The perfume conundrum – why it smells different on different people

I’m sure you’ve noticed that perfume never smells the same on any two people, a fact that can be jolly frustrating when you’re out shopping for a new scent. Something that smells divine in the bottle or when worn by a friend can easily seem cloying and repugnant once applied to your skin. So, why do these variations occur?

Well. As you would expect, it all begins in the nose. Our sense of smell is dependent on a small patch of specialised olfactory sensory neurons located high up in the nasal cavity. This patch is called the olfactory epithelium, and it is covered by a carpet of olfactory receptors. On average, humans tend to have around 450 different types of olfactory receptor, each capable of binding to a wide array of odour molecules. Unlike conventional receptors which only bind to one type of thing, olfactory receptors can be activated by many different molecules (and each molecule can activate many different receptors). Each molecule/receptor combination binds in a slightly different way, and these differences provide us with our nuanced sense of smell. In fact, your sense of smell is probably better than you think – researchers at Rockefeller University have found that humans are capable of detecting over one trillion individual scents.

Due to natural variation, different people have a different number and combination of olfactory receptors. This leads to different experiences of smell. Someone could find the aroma of patchouli in a perfume overpowering, whilst another may not be able to detect the scent at all. Whilst this difference in interpretation is certainly a part of the puzzle, it doesn’t explain why the same perfume smells different on different people. Don’t worry – I’m getting to that bit.

As you may know, each individual has a unique ‘skin chemistry’. This is influenced by a great deal of factors ranging from temperature, humidity and sweat composition to the types of medication you’re taking and the range of aromatic herbs in your diet. In some circumstances, your skin chemistry can alter by the hour. When you apply perfume, the naturally occurring chemicals on your skin mingle with those present in the perfume, creating a subtly different scent. The environment you’re in can also influence your perception of a smell – sampling a perfume in someone’s bedroom will often be an entirely different experience to testing a new brand at your local shop.

Along with the influence of your skin chemistry, the time after application can also have an impact on your perception of a perfume or cologne. Each concoction tends to be made up of three different ‘notes’ – top, middle and base. The top notes are the ones you smell immediately after application (their small and volatile structures evaporate easily and float straight towards the nose). The middle notes are next, emerging after around two hours due to their larger molecular weight. The base notes are the last to appear, a good five hours after initial application. They are the largest molecules, so require prolonged exposure to body heat in order to evaporate.

So, here we are. After a bit of discussion, it seems like the differences in perfume experience are due to a wide range of factors. Not only does your individual nose play a part, but so does the garlic bread you had for lunch and the weather that day. Pretty pot-luck, eh?

Tabitha Watson

Image Credit: [http://mac.h-cdn.co/assets/15/51/980×490/landscape-1450470504-best-perfume.jpg]

 

Posted in physics, science

How do headphones work?

With a market value set to reach $15.8 billion by 2025, chances are you own a pair of headphones. However, the odds of the average person knowing how they work are significantly worse.

At the most basic level, all speakers are made up of three main constituents: a cone (sometimes referred to as a diaphragm), a coil of wire and a permanent magnet. As shown in the main image, the cone is attached to the coil. The permanent magnet is situated within the coil.

Electricity is fundamental to the function of headphones – when it flows through the coil, it becomes an electromagnet. If the flow of the electricity is altered, the electromagnet either attracts or repels the permanent magnet. This combination of both attraction and repulsion induces motion in the coil, causing the cone to move. These movements generate vibrations (a.k.a. soundwaves) in the air – much like those produced by banging on the skin of a drum. As discussed in my previous post ‘How do we hear?’, the ear detects these vibrations and converts them into signals that can be processed by the brain.

Once the soundwaves are being produced, factors such as volume and pitch are controlled by the strength and frequency of vibration. In order to generate a louder sound, larger and more powerful vibrations are required. Pitches are determined by the frequency of the soundwave. The frequency is defined as the rate of the wave, illustrated by Figure 1. Whilst pitch is altered simply by increasing the power of vibration, frequency is governed more by the size of the speaker. Hence, huge subwoofers produce much better bass than a tiny in-ear headphone.
frequency1

Figure 1

Although humans are capable of hearing many different types of sound, headphones and other sound-systems can typically only produce two: monoaural and stereo. Monoaural is when the sound only comes from one source, such as someone speaking. This is the type of sound encountered during a phone conversation or from an old radio. Stereo sound is encountered when two speakers generate slightly different vibrations in order to emulate a 2D soundscape. Have you ever had a song begin in one headphone and move across to the other? That’s an example of stereo. Whilst it is possible to generate 3D sound artificially, it is a lot more time consuming. To be effective, speakers must be placed around the audience and each must play subtly different things. Currently, the only place that this is practical is for ‘surround-sound’ in cinemas. Though, given the passage of time, it may well become a future household staple.

Tabitha Watson

Image Creds: [http://www-cdn.sciencebuddies.org/Files/7472/6/speaker-diagram.png

images.tutorvista.com/cms/images/83/frequency1.PNG]

Posted in biology, science

How do we hear?

In order to hear the world around us, humans and other mammals rely on vibrations travelling in the air. To interpret these vibrations, the ear has evolved a complex system of canals and tiny hair-like protrusions, all working in harmony to generate sound as we know it.

The ear is a complex structure composed of three distinct parts, each with separate functions. The outer ear (or pinna) is the external section that protrudes from the side of the head. Responsible for the placement of sounds in relation to our bodies, the complex arches and valleys funnel vibrations into the ear canal and create a three dimensional soundscape.

Once the vibrations begin to move down the ear canal, they enter the middle ear. This section is composed of the auditory canal, which terminates at the eardrum (also known as the tympanic membrane). The eardrum is then attached to three tiny bones called ossicles, surrounded by a small pocket of air. Individually, these bones are the malleus, incus and stapes (or alternatively, the hammer, anvil and stirrup). The ossicles are then attached to a fluid-filled structure called the cochlea. It is here that the inner ear begins.

The primary function of the cochlea is to convert vibrations into electrical impulses to be sent down the auditory nerve and interpreted by the brain. In order to change the vibrations to impulses, a rather ingenious method is employed. Once the vibration reaches the cochlea from the ossicles, it travels down the basilar membrane whereupon it is detected by approximately 16,000 to 20,000 hair-like cells called cilia. These cilia are attached to a specialised part of the ear canal called the Organ of Corti, and it is here that the raw vibrations are converted to nerve impulses and passed along the auditory nerve to the brain. This is achieved by the deformation of the cilia – as they are moved by the vibrations, specialised ion channels are pulled open and the resultant influx of potassium and calcium ions depolarises the cells and produces an action potential.

So how are humans able to hear such a spectrum of different sounds and pitches? Well, it’s all down to the tapered shape of the cochlea. Due to their individual amplitudes, different frequencies of sound wave peak at different times as they travel down the ear canal. As higher frequency waves have larger amplitudes, they are not able to travel as far as lower frequency waves. Due to this, each section of cilia is sensitive to a particular frequency of wave – this is what enables the detection of such a vast spectrum of sound.

Tabitha Watson

Image Credit:

[http://dt7v1i9vyp3mf.cloudfront.net/styles/news_large/s3/imagelibra/E/Ear_01.jpg?W0hbNd_Wzq4sD071RFwOhUnzgBMQHi22=&itok=VJ-3sBGY]