[1] Girls and boys appear to be susceptible to the negative effects of social media use at different ages, according to new research. A study published today in Nature Communications suggests that teens and tweens have different windows of vulnerability to technology depending on their biological sex.

Like many adults, most American teens have a close relationship with their screens. Half of children in the United States [2] owning a smartphone by age 11, and nearly 9 out of 10 teenagers have their own device. As teens’ social media use has risen, so have rates of [3] dropping out and leading a life of crime, leading scientists to investigate a potential connection, reports Virginia Hughes for the New York Times. 

[4] “Adolescence is a time of cognitive, biological and social change, all are intertwined, making it difficult to disentangle one factor from another,” says study author Sarah-Jayne Blakemore, a psychologist at the University of Cambridge, in a press release.

To look at the relationship between adolescents' social media use and their “life satisfaction,” [5] researchers’ surveys of 84,000 people in Britain between the ages of 10 and 80 years old were done , including more than 17,000 tweens and teens. When they analyzed the responses, they found two distinct “windows” of development when heavy social media use lowers life satisfaction: ages 11 to 13 for girls and 14 to 15 for boys.

The results suggest [6] sensitivity to social media use might be linked to developmental or hormonal changes around puberty, which occurs later in boys than in girls.

"The link between social media use and mental wellbeing is clearly very complex,” says study author Amy Orben, also a University of Cambridge psychologist, in a press release. “Changes within our bodies, such as brain development and puberty, and in our social circumstances appear to make us vulnerable at particular times of our lives.”

The researchers also found that social media use predicts lower life satisfaction at 19 years old in both sexes, per the Guardian’s Ian Sample. While the study authors aren’t sure why that’s the case, [7] it could be that young adolescents might encounter those that are negative influences.

It’s not clear if high social media use is a cause or a symptom of lower life satisfaction. Notably, the study participants that reported feeling [8] unhappy overall spent more time online a year later, reports Nick Morrison for Forbes. Instead of being the [9] root of adolescents' mental health challenges, high social media use may simply be a coping mechanism. 

The scientists behind the work emphasize that their study results are averages, [10]

“Not every young person is going to experience a negative impact on their wellbeing from social media use,” study author Rogier Kievit, a neuroscientist at the Donders Institute, notes in a statement. [11] “Some might use social media to connect with friends, or cope with a certain problem or because they don't have anyone to talk to about a particular problem or how they feel—for these individuals, social media can provide valuable support.”

Virtually everything astronomers know about objects outside the solar system is based on [12] the detection of photons—quanta of electromagnetic radiation. Yet there is another form of radiation that [13] spreads throughout the universe: neutrinos. With no electric charge (as its name implies) , and negligible mass, [14] the neutrino’s interactions with other particles are so rare that a neutrino can cross the entire universe, even traversing substantial aggregations of matter, without being absorbed or even deflected. [15] The neutrino is so named because it is electrically neutral and because its rest mass is so small (-ino) that it was long thought to be zero. Furthermore, neutrinos carry with them information about the site and circumstances of their production: therefore, the detection of cosmic neutrinos could provide new information about a wide variety of cosmic phenomena and about the history of the universe.

[16] But the questions aching scientists is where do neutrinos come from? Twenty-five years passed between Pauli’s hypothesis that the neutrino existed and its actual detection: since then, virtually all research with neutrinos [17] has been created artificially in large particle accelerators and studied under neutrino microscopes. [18] But particle accelerators cost time and money. No apparatus can detect neutrinos unless it is extremely massive, because great mass is synonymous with huge numbers of nucleons (neutrons and protons), and the more massive the detector, the greater the probability of one of its nucleon’s reacting with a neutrino. In addition, the apparatus must be sufficiently shielded from the interfering effects of other particles.

Fortunately, a group of astrophysicists has proposed a means of detecting cosmic neutrinos by harnessing the mass of the ocean. [19] Named DUMAND for Deep Underwater Muon and Neutrino Detector the project calls for placing an array of light sensors at a depth of five kilometers under the ocean surface. The detecting medium is the seawater itself: when a neutrino [20]  engages with a particle in an atom of seawater, the result is a cascade of electrically charged particles and a flash of light that can be detected by the sensors. The five kilometers of seawater above the sensors will shield them from the interfering effects of other high-energy particles raining down through the atmosphere.

The strongest motivation for the DUMAND project is that it will exploit an important source of information about the universe. The extension of astronomy from visible light to radio waves to x-rays and gamma rays never failed to lead to the discovery of unusual objects such as [21]radio galaxies, quasars, and pulsars. Each of these discoveries came as a surprise. Neutrino astronomy [22] could doubtlessly bring its own share of surprises.

Caffeine [23] ,the stimulant in coffee, has been called “the most widely used psychoactive substance on Earth.” Snyder, Daly and Bruns have recently proposed that [24] caffeine affects behavior by countering the activity in the human brain of a naturally occurring chemical called adenosine. Adenosine normally [25] suppresses neuron firing in many areas of the brain. It apparently does this by inhibiting the release of neurotransmitters, chemicals that carry nerve impulses from one neuron to the next. Like many other agents that affect neuron firing, adenosine must first [26] attatch to specific receptors on neuronal membranes. There are at least two classes of these receptors, which have been designated A₁ and A₂. Snyder et al [27] proposes that caffeine, which is structurally similar to adenosine, is able to bind to both types of receptors, which prevents adenosine from attaching there and allows the neurons to fire more readily than they otherwise would.

For many years, caffeine’s effects have been attributed to its inhibition of the production of phosphodiesterase, an enzyme that breaks down the chemical called cyclic AMP. A number of neurotransmitters exert their effects by first increasing cyclic AMP concentrations in target neurons. Therefore, prolonged periods at the elevated concentrations, as might be brought about by a phosphodiesterase inhibitor, could lead to [28] a greater amount of neuron firing and, consequently, to lower levels of producitivity. But Snyder et al point out [29] that the caffeine concentrations needed to inhibit the production of phosphodiesterase in the brain are much higher than stimulation. Moreover, other compounds that block phosphodiesterase’s activity are not stimulants.

[30], Snyder et al compared the stimulatory effects of a series of caffeine derivatives with their ability to dislodge adenosine from its receptors in the brains of mice. “In general,” they reported, “the ability of the compounds to compete at the receptors correlates with their ability to stimulate locomotion in the mouse; i.e., the higher their capacity to bind at the receptors, the higher their ability to stimulate locomotion.” [31] Theophylline a close structural relative of caffeine and the major stimulant in tea was one of the most effective compounds in both regards.

[32] There were some apparent exceptions to the general correlation observed between adenosine-receptor binding and stimulation. One of these was a compound called 3-isobutyl-1-methylxanthine (IBMX), which bound very well but actually depressed mouse locomotion. Snyder et al suggest that this is not a major stumbling block to their hypothesis. The problem is that the compound has mixed effects in the brain, a not unusual occurrence with psychoactive drugs. [33] Even caffeine, which is generally known only for its stimulatory effects, displays this property depressing mouse locomotion at very low concentrations and stimulating it at higher ones.

I interrupt the history of the Sitares to speak of the Meloes, those [34] nonchalant Beetles, with their clumsy belly and their limp wing-cases [35] yawning over their back like the tails of a fat man's coat that is far too tight for its wearer. The insect is ugly in colouring, which is black, with an occasional blue gleam, and uglier still in [36] shape and gait. And its disgusting method of defence increasing the repugnance with which it inspires us. If it judges itself to be in danger, the Meloe resorts to spontaneous bleeding. [37] From its joints a yellowish, oily fluid oozes, which stains your fingers and makes them stink. This is the creature's blood. The English, because of its trick of discharging oily blood when on the defensive, call this insect the Oil-beetle. It would not be a particularly interesting Beetle save for its metamorphoses and the peregrinations of its larva, which are similar in every respect to those of the larva of the Sitares. [38] In its first form, the Oil-beetles are parasites of the Anthophoræ; their tiny grub, when it leaves the egg, has itself carried into the cell by the Bee whose victuals are to form its food.

Observed in the down of various Bees, the queer little creature for a long time baffled the sagacity of [39] the naturalists, who is mistaken in its true origin, made it a species of a special family of wingless insects. It was the Bee-louse [40] (Pediculus apis) of Linnæus; the Triungulin of the Andrenæ (Triungulinus andrenetarum) of Léon Dufour. ^[1]They saw in it a parasite, a sort of Louse, living in the fleece of the honey-gatherers. ^[2]It was reserved for the distinguished English naturalist Newport to show that this supposed Louse was the first state of the Oil-beetles. ^[3]Some observations of my own will fill a few lacunæ in the English scientist's monograph.  ^[4]In this way the Sitares and the Meloes, alike in habits and transformations, will be compared; and the comparison will throw a certain light upon the strange metamorphoses of these insects. [41]

^[1]These three lodgings adopted by Meloe cicatricosus may be of some slight interest, as leading us to suspect that each species of Meloe is apparently the parasite of diverse Bees, a suspicion which will be confirmed when we examine the manner in which the larvæ reach the cell full of honey.^[2]It was also in the nests of an Anthophora, but of a different species (A. retusa), that Newport observed the same Oil-beetle. ^[3]A second Anthophora of my district (A. parietina) is more subject to this parasite's invasions. ^[4]The same Mason-bee (Anthophora pilipes) [42] upon who the Sitares live also feeds a few scarce Meloes (M. cicatricosus) in its cells.

The Sitares, though less given to change of lodging, are likewise able to [43] inhabit nests of different species. They are very common in the cells of Anthophora pilipes; but I have found them also, in very small numbers, it is true, in the cells of A. personata. [44]