Age of first sexual encounter may effect relationship happiness and success in later life

It is widely accepted that modern society runs at a faster pace than it used to, with children and teenagers experiencing many life events at much younger ages than did their parents and grandparents. This 'growing up fast' way-of-life is of great concern to many parents, especially when their children's ventures into sexual relationships are concerned, who are worried that their children are not ready such encounters. Is there really a cause for concern, however, or are parents just fussing and worrying for nothing?

Humans are a very social species and, in resource-abundant environments, usually favour a mating pattern called monogamy, where one person has just one sexual partner for a long period of time. Such relationships are rewarding and healthy when they work, creating stable conditions in which to raise a family.

Recent research from the University of Texas has suggested that, unfortunately, there is. The study, which was carried out by psychologist Paige Harden, has tried to determine whether the timing of an individual's first sexual encounter affects their romantic relationships later in life and whether it can predict factors like relationship satisfaction, the likelihood to marry and the number of sexual partners.

Dr. Harden conducted this research via a meta-analysis, using data from the [US] National Longitudinal Study on Adolescent Health and followed 1659 people from their early teens to young adulthood (<29 years old). As part of this research, Harden classified each participant in one of three categories in regard to their age at their first experience of having sexual intercourse: Early (<15), On-time (15-19) or Late (>19), before comparing the qualities of their romantic relationships/encounters.

As she predicted, the most highly educated participants from greater income families were older at the time of their first experience of sexual intercourse. The study appears to show that first experiencing sex at a later age is beneficial to an individual, as those in the study showed greater levels of marriage (or living with their partner), were less likely to be dissatisfied with their partner, were less likely to persist in an abusive relationship and typically had less sexual partners over the course of their life.

In contrast, those who were younger at their first encounter tended to have many more sexual partners and typically showed a greater level of romantic dissatisfaction. This data also fit with a clear pattern: those in the 'Early' group showed much more exaggerated trends than those in the 'On-Time' category.

Dr. Harden explains these results by suggesting that waiting until later to first have sexual intercourse may be beneficial to an individual as it allows their cognitive and mental development to have finished first. As well as having obvious benefits such as greater confidence, which makes an individual more likely to walk away from abuse and inappropriate pressure, being fully developed [mentally] also appears to enable an individual to learn more 'healthy' relationship skills. Harden suggests that it is these skills in particular that allow an individual to form healthier and happier relationships, which are more likely to endure for longer periods of time.

Although these findings are worrying, and seem to show that being young when having sexual intercourse for the first time can have series and long-term negative side-effects,  more research needs to be carried out into these ideas before any significant statement can be made. Dr. Harden has acknowledged this, saying that "we are just beginning to understand how adolescents' sexual experiences influence their future developments and relationships". For the time being, however, it looks like parents are right after all, and children may indeed, be 'growing up too fast'.

Black mamba venom may be a super painkiller!

French scientists have recently identified that the toxic venom of the black mamba, one of Africa's most dangerous and feared snakes, has a huge potential for its use in medicine. The research, carried out by Dr. Eric Lingueglia from the Institute of Molecular and Cellular Pharmacology near Nice, has identified that the snake's poison contains a unique class of chemicals called mambalgins, which act as painkillers in mice that are as strong as morphine but have none of its associated side effects.

The black mamba, Dendroaspis polylepis, is named after the dark skin inside its mouth rather than after the colour of its scales. As well as being among the most poisonous snakes in the world, the 3 metre long mamba is also the fastest and can even outrun humans. These attributes, along with its highly aggressive nature, have made the snake highly feared among all the African peoples that live alongside it.

These properties of black mamba venom are of huge interest to the healthcare sector because, despite its heavy use, morphine is highly addictive and has many severe side effects for those taking the drug, which include headaches, a reduction in their thinking capacity, nausea and muscle spasms. A new painkiller then, which is effective enough to remove the same agonising pains as morphine but with none of its side effects would be like a 'magic bullet' in pharmacology, being hugely popular among both doctors and their patients.

Research has identified that these useful mambalgins may work in such a beneficial way because they operate via a previously unseen neural pathway that is not targeted by any other studied venom or by the palliative drugs currently in production. Dr. Nicholas Casewell, a world-leading expert in snake venom from the Liverpool School of Tropical Medicine, is avid over the potential implications of black mamba toxins to medicine and has said that mambalgins are "a really great example of drugs from venom, we're talking about an entirely new class of analgesics".

Dr. Lingueglia believes that this rather surprising property of black mamba venom may be as an intentional effect of the poison, which helps to incapacitate the snake's prey so that it is less likely to escape; or may be due to a chance, but useful, fluke in mice, resulting from the differences in brain chemistry between the rodents and the snake's usual prey.

Whatever the reason for the venom's remarkable analgesic properties in mice however, scientists are excited about the discovery and are hopeful that the toxins will have the same effects in humans as our brain chemistry is very similar to that of the rodents (which is why mice are often used in scientific studies). It is likely that there will be extensive research into mambalgins in the near future, which will hopefully lead to a new drug that acts as a safer alternative to morphine.

From black to white: is calcium really that important?

The majority of us are at ease with Darwin's concept of evolution and understand how the 'survival of the fittest' has led to the vast abundance of life on Earth. Obviously, humans are no exception to this rule and evolution has moulded us into what we are today. Evolution, for example, selected for the first of us who began to move on two legs as this freed up our hands for better tool use; and selected for those who chose to live in social groups, which provided much more protection and help than did living alone. Without evolution it is doubtful that any life would exist on Earth at all, especially not in the form of hugely sophisticated organisms like humans.

Life on Earth began sometime around 4 billion years ago. It is believed that single-celled organisms first evolved on the shores of primordial oceans, which were abundant in the resources needed for life. Over time, these cells eventually evolved into the countless forms of life that we see on Earth today.

Most of you won't be surprised by any of this; it makes sense, after all. Something you might find surprising however, is why scientists believe that the early humans settling Europe evolved from being black to white. Obviously the sun's rays are less intense in Europe than they are in Africa, meaning that European settlers wouldn't have needed to produce as much of the pigment melanin in their skin, which absorbs ultraviolet (UV) radiation. Producing less melanin then would have provided such individuals with an advantage as they wouldn't have been wasting energy producing proteins their body didn't really need. This saved energy could then have been dedicated to more important processes (like keeping warm in the colder climate, for one thing).

Although this theory makes sense logically and saving energy by producing less melanin could quite plausibly have been the difference between life and death in the harsh European winters, is it really enough to have driven the evolution of one of our most noticeable racial polymorphisms?

Many scientists believe not, at least not by itself anyway, and research into this question has provided a rather odd alternative. Simply put, many scientists now believe that Europeans evolved from having black skin to white skin due to calcium!

Calcium is an fundamental resource for our bodies, with its ions having essential roles in muscle contraction; in propagating nerve impulses; and, arguably most importantly, in forming our skeletons (via binding with phosphorous to form a very stable salt called calcium phosphate). Despite its importance, calcium is rare in nature and is extremely difficult to acquire naturally as part of our diets. As always however, Nature provided early man with an ingenious way around this and all humans are able to make vitamin D in their skin when it is exposed to sunlight (in much the same way as plants photosynthesise sugars from sunlight to use as energy). Vitamin D greatly increases the affinity of calcium absorption in the gut, allowing the body to absorb much more of any calcium that it consumed than it would otherwise be able to.

Due to this ability, most people are able to acquire enough calcium (especially during the summer) to lead normal and healthy lives, and indeed, our African ancestors would have had strong bones and efficient muscles. The problems arose however, when early explorers entered Europe where the sun's rays are much less intense. This meant that the melanin pigments in their black skin were able to absorb much more sunlight than they could while in Africa and, as a result, vitamin D could no longer be produced.

Fossil evidence suggests that it was not long before the health of these explorers deteriorated, and many adult skeletons from the period show symptoms of osteomalacia (a disease where bones soften due to lack of calcium and deform under the weight of walking), and many may have suffered from a range of muscle weakness and epileptic disorders as their reserves of calcium were depleted and less and less could be replaced from bone stripping. Obviously such ill effects greatly reduced an individual's chances of survival and those with slightly lighter skin would have been more likely to live longer. Being healthier and living longer meant that they would have been more likely to survive to reproduce and slowly, the 'lighter' genes (which produced less melanin), would have spread through the population. In each generation the palest individuals would have been most successful at surviving and breeding so, over time, European humans would have got paler and paler until their skin was as white as it is in their descendants now.

As if this selection pressure wasn't enough to drive for whiter skin, having low levels of calcium and brittle bones had another major problem for women in particular - it hindered childbirth. Many women had such brittle pelvises that they broke under the strain of labour, virtually guaranteeing that both the infant and the mother would die. Furthermore, many children suffered from severe rickets due to a lack of calcium during childhood and puberty. This meant that such individuals were physically smaller than they should have been and many women suffered from underdeveloped hips that were too narrow for a baby to pass through. As a result, such a mother and her baby would have died during labour. Thus, many of the darker individuals would have been unable to give birth so that the darker genes disappeared from the European populations very quickly - being strongly selected against by Nature!

The degree of deformity that rickets can lead to can be very extreme, almost completely debilitating a child suffering with the condition throughout their entire life.

Scientists also believe that this explains why the vast majority of Europeans (and those in their descendent colonies such as Australia and the USA) can eat dairy as a stable component of their diet. This is actually quite abnormal, both in the animal kingdom and among other ethnicities of humans, as rennin (the enzyme required to digest milk) usually stops being produced by the body in infancy after the individual has been fully weaned. Thus, most humans are lactose intolerant and experience unpleasant symptoms if they drink milk or eat too much dairy-based produce. Humans evolving in Europe however, needed as much calcium as possible and would have been under strong selection pressure to continue producing rennin throughout their lives as milk is an unrivalled source of calcium.

Thus, the importance of calcium to the human body has made it an invaluable component that we need to survive. Too little calcium leads to severe health conditions that are so extreme that they can even drive evolution into turning black humans, who have very active melanocytes (melanin-producing skin cells), into white humans who have very little sun-protective pigments in their skin (allowing them to produce more vitamin D).

Mountain gorillas seen disarming poachers traps!

Everyday, animal trackers set out from the Karisoke Research Center into an isolated area of Rwandan rainforest aiming to find and disarm as many of the dangerous and illegal traps set by poachers as they can find. The trackers efforts are crucial in helping to protect the extremely rare mountain gorillas (Gorilla beringei beringei) that inhabit the region, which are classified as being 'Critically Endangered' by the IUCN and are predicted to become extinct within 10 years if we fail to conserve them.

When tracker John Ndayambaje set out one morning he was fully expecting to see poachers traps. Sure enough, he located a clan of gorillas and spotted a snare trap nearby. Although many poachers don't set snare traps to catch gorillas, as adults of the species are easily strong enough to break free, they are capable of killing juveniles so he knew that he must disarm it.

When John moved to approach the trap however, a silverback called Vubu grunted at him, presumably warning him to stay away. As John watched, two younger gorillas named Rwema and Dukore made their way over to it and carefully broke it, working confidently and quickly, which suggests that they've had extensive experience with the traps in the past. Rwema and Dukore then searched the surrounding foliage, joined by a third member of the Kuryama Clan called Tetero, and disarmed several more traps that John hadn't yet seen.

Rwema and Dukore work together to disarm a snare trap set by poachers.

This remarkable ingenuity has undoubtedly arisen in response to the very real dangers that the traps pose and is a superb example of mountain gorilla intelligence and their ability to learn. Researchers at the Karisoke Research Center believe that the gorillas watched human trackers tackling the traps and copied how they disarmed them. Although fascinating to watch, Veronica Vecellio (the Centre's gorilla program coordinator) was not surprised by the events and said that she is "always amazed and very proud when we [the Centre's researchers] can confirm that they are smart".

Mirrors can cure phantom pains? Who knew...

Many people who have lost limbs in accidents, to amputation and even those born without correctly formed limbs, experience strange sensations in the absent limb or appendage. These feelings are known as phantom sensations and are very common, with around 70% of amputees experiencing phantom limbs.

Although scientists do not know what causes phantom limbs definitively, the common consensus is that the sensations are formed by the reorganisation of somatosensory cortex in the brain. It is believed that once the nerves for the missing limb stop receiving stimuli, they are removed by the brain to give more room to functional neurones. This also explains why a person's hearing gets better if they lose their sight - by replacing the now redundant 'eye processing' neurones with those that deal with hearing, the brain can analyse sounds more efficiently. Phantom limbs are thought to occur when this reorganisation is maladaptive, or is not fully completed, so that the brain still receives phantom signals from neurones for limbs that are no longer present.

The symptoms of phantom limbs offer some support for this theory since the sensations that patients experience are often similar. Usually, patients describe the phantom limb as being shorter than the original was. The difference in size can be very pronounced, being as much as 6 inches shorter in some cases! Many patients also describe feeling itches and tingling sensations in their phantom limb, which are symptoms that can all be explained by the reduction in processing capacity for the limb in the brain.

Whereas this is all very interesting, the phantom sensations don't stop here for many patients and the majority of individuals who experience this phenomenon suffer from varying degrees of discomfort and pain. Phantom Limb Pain (PLP) is very common and, as with phantom limb syndrome, doctors don't really know why it occurs. There are 3 leading theories however, which all have strong support within the medical and scientific communities:

• The first is called maladaptive plasticity and is the same as the theory discussed above, suggesting that PLP is the result of maladaptive changes in the neuronal distribution of the somatosensory cortex following amputation.
• The second suggests that PLP is a result of the conflict between the signals from the missing limb's old neurones, which are telling the brain that the limb is there, with the information from the patient's eyes, which is telling them that the limb is not there. It is believed that the conflict between this information confuses the brain, leading to intense pain in the phantom limb.
• The last generally accepted explanation suggests that vivid memories of limb positions kick in after it has been amputated, and that these memories hold the limb in a certain position that the patient is unable to alter.

Without further understanding of the causes of PLP however, it is unlikely that scientists can develop a 'fix all' cure for patients due to the complexity of the condition. This is a real problem for many patients of PLP since the condition is most likely neurological, meaning that pain killers have no effect as a palliative and attempts to use drugs have repeatedly failed in the past.

A promising treatment for PLP does exist however, which has been successful in many cases. The treatment was developed by Vilayanur S. Ramachandran and his colleagues in the 1990's and involves the use of mirrors to trick a patient's senses into thinking that they are moving their phantom limb. 

This trickery is accomplished using a mirror box, in which the patient places their healthy limb in one hole and their stump in the neighbouring one. The top of the box is covered over their amputated limb, which the patient then appears to see as being whole again by watching the reflection of their healthy limb. When ready, the patient is asked to perform  'mirror symmetric' movements in both limbs simultaneously. Their brain then interprets moving their phantom limb and appears to 'see' it moving so any conflicting signals disappear, allowing the limp to shift from uncomfortable, painful positions.

Ramachandran's mirror box. Patients suffering from PLP put their healthy and phantom limbs into the box and, due to  the reflection of the mirror, appear to have two healthy limbs again.

A good example for mirror box therapy (based on an actual case), would be to imagine that one of your hands has been amputated. Following the operation you experience the sensation that your missing hand is constantly clenched, with the feeling being so strong that you are continuously in pain. In the therapy you are asked to clench and unclench both of your hands at the same time. By appearing to see your phantom hand move, your brain interprets that it is now unclenched and the pain disappears. 

Regular sessions of mirror box treatment have been able to alleviate PLP in many patients until it eventually disappears by itself, which occurs in most cases given enough time. As with the causes of phantom limbs and its associated pain, scientists can only offer theories to how mirror therapy works and it is possible that we may never know definitively due to the complexity of the human brain. Developing our understanding of mirror therapy may help to resolve an exceedingly curious phenomenon that has long baffled scientists and medics alike.