Glory to Our Martyrs&;#63; Really&;#63;&;#33;

Biden's Get Around Parole Program for Inadmissible Migrants Flies Them Into 50 Cities

Issue 22 (May 2024) of CURIOUS is out now‚ bringing you science highlights for the month plus deep dives into intriguing topics‚ interviews‚ exclusives‚ diary dates‚ and explanations for some of Earth’s most perplexing natural phenomena and landscapes.In This Issue…OUR COVER STORY: What Happens In A Nuclear Blast&;#63;The nuclear weapons of today are much more powerful than those of WW2 – what would it look like if they went off&;#63;DEEP DIVE: &;quot;Brain Food&;quot; – Is There Anything To It&;#63;Can we use our diet to give the brain a boost&;#63; And if so‚ how&;#63;WE HAVE QUESTIONS: The Biggest Wild Goose Is… Poisonous&;#63;Revelations of a comedy-nature podcast.WHERE ON EARTH: Raja Ampat: &;quot;The Last Paradise On Earth&;quot;The Indonesian archipelago of Raja Ampat is home to all sorts of natural wonders: from walking sharks and “goth” rays to rare colorful orchids.Exclusive: Meet Author Professor Chris French and read an excerpt from his new book The Science of Weird Shit.Plus: News‚ diary dates‚ what to see‚ watch‚ and read this month‚ and much more.

There’s something about the immense beauty and mystery of nature that just can’t help but make you think: math. Take‚ for example‚ a new study in which an international team of researchers have figured out the previously unknown formulas behind flocking – or at least‚ some small part of the phenomenon – allowing us to at long last harness the ingenuity of nature for our own mechanical purposes.“This area of research is important since animals are known to take advantage of the flows‚ such as of air or water‚ left by other members of a group to save on the energy needed to move or to reduce drag or resistance‚” explained Leif Ristroph‚ an associate professor at New York University’s Courant Institute of Mathematical Sciences and the senior author of the paper‚ in a statement.The team restricted their study to birds moving in a column – those formations in which groups of flyers will line up directly behind each other – rather than attempting some of the more adventurous murmurations achieved by some species of bird. That shouldn’t be seen as a shortcoming‚ by the way – those movements can be so complex as to resemble the quantum dynamics of superfluid helium‚ and even collecting sufficient data to model equations from can be prohibitively difficult.In fact‚ previous work on the math behind flocking has considered even fewer birds: only two‚ in a paper from the same team some five years ago. But the new paper has shown just how important expanding the study was to understanding the movements of these groups of animals – because as it turns out‚ the effects of the dynamics involved actually depend on the size of the group.“The aerodynamic interactions in small bird flocks help each member to hold a certain special position relative to their leading neighbor‚” explained Sophie Ramananarivo‚ an assistant professor at &;Eacute;cole Polytechnique Paris and one of the paper’s authors. “But larger groups are disrupted by an effect that dislodges members from these positions and may cause collisions.” This observation was confirmed with a “mock flock” – mechanical replica wings‚ created by the team and driven through water to model the air flow around real birds in flight. The cut-off point‚ they discovered‚ was about four: fewer flyers than that‚ and the aerodynamic interactions are a help to each individual relative to the others‚ Ristroph explained. “If a flyer is displaced from its position‚ the vortices or swirls of flow left by the leading neighbor help to push the follower back into place and hold it there‚” he said. “This means the flyers can assemble into an orderly queue of regular spacing automatically and with no extra effort‚ since the physics does all the work.”More than that‚ however‚ and staying in formation gets difficult. “[The] flow interactions cause later members to be jostled around and thrown out of position‚ typically causing a breakdown of the flock due to collisions among members‚” Ristroph said. “This means that the very long groups seen in some types of birds are not at all easy to form.”Essentially‚ the team discovered‚ each bird is affected by the bird in front – but is unable to exert any reciprocal effect back to its predecessor. These waves‚ dubbed “flonons” by the researchers‚ add up through the column‚ so by the time we get to the back of the queue‚ birds can be oscillating wildly: they “likely have to constantly work to hold their positions and avoid crashing into their neighbors‚” Ristroph explained.But while that’s all very interesting‚ is it particularly helpful for those of us without feathers&;#63; Well‚ in fact‚ yes. “Our findings […] raise some interesting connections to material physics‚” pointed out Joel Newbolt‚ an NYU graduate student in physics at the time of research. “[The] birds in an orderly flock are analogous to atoms in a regular crystal.”And the study might have some more immediate real-world implications‚ too‚ Ristroph added. “Our work may also have applications in transportation – like efficient propulsion through air or water‚” he suggested‚ “and energy‚ such as more effectively harvesting power from wind‚ water currents‚ or waves.”The study is published in the journal Nature Communications.

We're going to put it out there: ostriches are weird‚ but they are also very cool. Not only are they the largest bird on the planet‚ growing up to 2.8 meters (9.2 feet) tall but they are also the fastest flightless birds out there. But did you also know that they also have the largest eyes of any land animal&;#63; In fact‚ their eyes are so large that they dwarf their own brains by comparison.Ostrich eyes are really big. They are about 2 inches (5 cm) across‚ which makes them about five times larger than a human eye. The optical design of their eyes is set up in a way that the lens and cornea contribute equally to the total optical power.Interestingly‚ analysis of ostrich eyes has revealed them to effectively be scaled-up versions of the eyes of other birds‚ like the common starling and even the tawny owl. This similarity may be quite striking at first‚ considering that the eyes of these two bird species appear to have different shapes. This‚ it has been hypothesized‚ may be a result of the birds' differing weights.For instance‚ the overall shape of an owl eye may result from the evolution of a large eye – both in terms of its aperture and axial length (the measure from the front to the back) – which needs to fit into a small skull and still be light enough for powerful flight.However‚ because they are flightless birds‚ ostriches are not constrained by the same weight issues‚ so they have developed the characteristic global shape to their massive peepers. This may offer a range of advantages‚ especially in relation to the size of the visual field it would offer the bird.Ostriches have a monocular field – the vision in each eye individually – that extends to about 155°‚ which helps them scan the horizon for potential dangers. However‚ ostriches have a substantial blind spot above and behind their heads which is caused by the way their eyes sit in their skulls to protect them from the tropic sun.This type of natural shielding may be needed to prevent retinal damage‚ but it does make them look like angry sock puppets.Ostriches also have binocular vision in front of their bills which is invaluable for searching for food. This visual field extends vertically through 80° and up to a width of around 20°.It’s quite a small range‚ but it helps them to forage for food on the ground. As they are principally herbivores‚ this means ostriches need to be able to focus on small objects like leaves‚ seeds‚ and flowers. They also sometimes eat small insects and vertebrates when the feeling takes them (we’ve all been there) so this visual field also helps them target potentially moving prey.Yet while their eyes are colossal and bulging‚ they are ridiculous compared to the bird’s modestly sized brain. Ostriches have brains that are about 59.26 mm (2.3 inches) long and about 42.30 mm (1.6 inches) wide. Visually‚ this would look like a golf ball wired up to two billiard balls.Still‚ the birds have clearly evolved in a way that does not need them to have a large brain. If hiding doesn’t work‚ the bird can usually just outrun any problems that come its way.

On the boundary of the Caribbean Sea and the Atlantic Ocean is the Puerto Rico Trench‚ the deepest in the Atlantic Ocean. Kilometers above it‚ the ocean's surface is dipped slightly‚ pulled by an anomaly of Earth's gravity. If you drop an object there‚ it will fall slightly faster than elsewhere on the planet or in the surrounding area. Meanwhile navigation equipment can be thrown off by the anomaly‚ causing false readings for sailors in the area.So what is causing the gravity anomaly‚ and are there any others like it&;#63;How did we first discover gravity anomalies&;#63;In 1671‚ astronomer Jean Richter traveled from Paris‚ France‚ to Cayenne‚ French Guiana in South America. With him‚ he took a pendulum clock. While the clock had been accurate in Paris‚ he noticed that in Cayenne it ran slowly‚ losing a full two and a half minutes every day. No biggie‚ the pendulum was shortened to make the clock accurate. However‚ when he returned to Paris he found that the clock was running too quickly‚ by two and a half minutes each day.Though it may feel the same when you jump up and down in Brazil or Canada‚ the rate at which you fall is not uniform. What mathematician Christiaan Huygens realized after hearing of Richter's clock was that it was experimental evidence that the Earth was rotating. Later‚ Newton showed using data from a similar pendulum clock and Jupiter's equatorial bulge‚ that the Earth bulged at the equator due to the centrifugal force of its rotation‚ and estimated by how much. Near the equator gravity acts upon you less than it does near the poles‚ as you are further away from the bulk of the Earth's mass.However‚ the gravity at the Puerto Rico Trench differs from the area surrounding it. It‚ along with several others like it around the planet‚ are what are now referred to as gravity anomalies.What is a gravity anomaly&;#63; Gravity anomalies are where an object observed in free fall accelerates at a rate different to the rate models of gravity for that location would predict. At the Puerto Rico Trench‚ gravity has been found to be -380 milliGal‚ making it the biggest negative gravity anomaly on Earth. Another in the Indian Ocean is where gravity has been found to be lowest‚ compared to what was expected.What is causing the Puerto Rico Trench gravity anomaly&;#63; In 1977‚ geophysicist Peter Molnar attempted to find out what was causing this unexpected downwards force. Just as slightly higher gravity at the poles is due to being closer to the bulk of Earth's mass‚ he knew a likely source: something huge and dense must be under the surface.In a paper published in Geophysical Journal International‚ he explained that previous models of gravity had assumed that the thickness of the Earth's crust (the lithosphere) was pretty uniform. Looking at the area‚ he realized that wasn't the case‚ and that the anomaly was likely caused by a large &;quot;hanging flap&;quot; of the Atlantic lithosphere.&;quot;The residual gravity anomalies are then consistent with the existence of a subcrustal dense mass‚ that could be the hanging slab of lithosphere‚&;quot; Molnar wrote in the study.&;quot;The value of this excess mass depends upon more arbitrary assumptions for the crustal mass in the Puerto Rico Trench and its landward wall‚ but if the other assumptions above are realistic‚ the dense mass is required and is adequate to bend the surface down at the trench.&;quot;Though not the first to propose the slab of crust as an explanation‚ Molnar was able to provide estimates of the mass and size of the object causing the gravity anomaly above.An earlier version of this article was published in March 2023.

This week‚ bioluminescence in animals has been found to have existed for at least 540 million years‚ bacteria on the ISS is mutating into new strains not seen before on Earth‚ and an engraving on a prehistoric bear bone is the oldest example of Neanderthal culture. Finally‚ we explore the myth behind the “deadly” pharaoh’s curse.Subscribe to the IFLScience newsletter for all the biggest science news delivered straight to your inbox every Wednesday and Saturday. Uranus May Be Filled With A Lot More Methane Than We ThoughtUranus and Neptune are often referred to as ice giants‚ with scientists believing that they are mostly made up of &;quot;icy&;quot; materials such as water‚ methane‚ and ammonia‚ surrounding a hot‚ rocky core. Astrophysicists believe this is the case because the region they formed in would likely have been abundant in the necessary components‚ hence the expectation of a lot of water and ice. But now‚ astronomers taking a closer look at Uranus believe it could be filled with a lot more methane than previously thought. Read the full story hereBioluminescent Animals Have Been Glowing For At Least 540 Million YearsEvidence has been found for bioluminescence having existed among animals 540 million years ago‚ more than doubling the previous record. Besides altering how we picture the oceans of the world in the Ediacaran era and thereafter‚ the finding could shed light (sorry) on the reasons bioluminescence evolved and is so widely used by creatures today. Read the full story hereBacteria On The ISS Have Mutated Into Something Not Seen On Earth BeforeMovies and TV shows give the impression of space stations as aseptic and squeaky-clean environments. But wherever there are humans‚ there are all the bacteria that we bring with us. Bacteria have found niches in the International Space Station (ISS) and since they can evolve pretty quickly‚ a species has been seen becoming distinct from its earthly counterparts. Read the full story hereMeet A Megaraptor: New Dinosaur Footprints Reveal Raptors Grew Scarily BigA remarkable coincidence has seen a late Cretaceous mudflat preserve the footprints of two different types of raptors. More astonishingly still‚ one of these prints comes from a previously unknown species larger than any raptor we have previously found. Fujianipus yingliangi is estimated to have been 1.8 meters (5 foot 11 inches) high at the hip‚ and a terrifying 5 meters (16 feet) long‚ much larger than Jurassic Park's already supersized Velociraptors. Stand by for future big-screen appearances. Read the full story hereEngraved Bone Of Prehistoric Bear Is The Oldest Example Of Neanderthal CultureSometime between 115‚000 and 130‚000 years ago‚ a Neanderthal living in a cave in Poland etched a series of markings into a bear bone. Despite consisting of just 17 lines‚ the engravings converted the bone into one of the oldest known symbolic items in Europe and one of the earliest to be associated with Neanderthals. Read the full story hereTWIS is published weekly on our Linkedin page‚ join us there for even more content.Feature of the week: The Pharaoh’s Curse: Does Opening A Tomb Really Lead To An Untimely Death&;#63;In addition to being one of the most significant archaeological finds of the 20th century‚ the tomb of Tutankhamun also turned out to be a glorified can of worms‚ the opening of which has inspired countless myths‚ movies‚ and pseudo-archaeological theories. In particular‚ the so-called &;quot;Pharaoh’s Curse&;quot; became a globally recognized phenomenon – but where did this myth come from&;#63; Read the full story here More content:Have you seen our e-magazine‚ CURIOUS&;#63; Issue 21 April 2024 is out now. Check it out for exclusive interviews‚ book excerpts‚ long reads‚ and more.PLUS‚ the entire season 3 of IFLScience's The Big Questions Podcast is available now.

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer‚ send it to curiouskidsus@theconversation.com.How do crystals form&;#63; – Alyssa Marie‚ age 5‚ New MexicoScientifically speaking‚ the term “crystal” refers to any solid that has an ordered chemical structure. This means that its parts are arranged in a precisely ordered pattern‚ like bricks in a wall. The “bricks” can be cubes or more complex shapes.I’m an Earth scientist and a teacher‚ so I spend a lot of time thinking about minerals. These are solid substances that are found naturally in the ground and can’t be broken down further into different materials other than their constituent atoms. Rocks are mixtures of different minerals. All minerals are crystals‚ but not all crystals are minerals.Most rock shops sell mineral crystals that occur in nature. One is pyrite‚ which is known as fool’s gold because it looks like real gold. Some shops also feature showy‚ human-made crystals such as bismuth‚ a natural element that forms crystals when it is melted and cooled.Pyrite in black shale rock from a quarry in Indianapolis‚ Ind. James St. John/Flickr‚ CC BYWhy and how crystals formCrystals grow when molecules that are alike get close to each other and stick together‚ forming chemical bonds that act like Velcro between atoms. Mineral crystals cannot just start forming spontaneously – they need special conditions and a nucleation site to grow on. A nucleation site can be a rough edge of rock or a speck of dust that a molecule bumps into and sticks to‚ starting the crystallization chain reaction.At or near the Earth’s surface‚ many molecules are dissolved in water that flows through or over the ground. If there are enough molecules in the water that are alike‚ they will separate from the water as solids – a process called precipitation. If they have a nucleation site‚ they will stick to it and start to form crystals.Rock salt‚ which is actually a mineral called halite‚ grows this way. So does another mineral called travertine‚ which sometimes forms flat ledges in caves and around hot springs‚ where water causes chemical reactions between the rock and the air.You can make “salt stalactites” at home by growing salt crystals on a string. In this experiment‚ the string is the nucleation site. When you dissolve Epsom salts in water and lower a string into it‚ then leave it for several days‚ the water will slowly evaporate and leave the Epsom salts behind. As that happens‚ salt crystals precipitate out of the water and grow crystals on the string.Many places in the Earth’s crust are hot enough for rocks to melt into magma. As that magma cools down‚ mineral crystals grow from it‚ just like water freezing into ice cubes. These mineral crystals form at much higher temperatures than salt or travertine precipitating out of water.What crystals can tell scientistsEarth scientists can learn a lot from different types of crystals. For example‚ the presence of certain mineral crystals in rocks can reveal the rocks’ age. This dating method is called geochronology – literally‚ measuring the age of materials from the Earth.One of the most valued mineral crystals for geochronologists is zircon‚ which is so durable that it quite literally stands the test of time. The oldest zircons ever found come from Australia and are about 4.3 billion years old – almost as old as our planet itself. Scientists use the chemical changes recorded within zircons as they grew as a reliable “clock” to figure out how old the rocks containing them are.Some crystals‚ including zircons‚ have growth rings‚ like the rings of a tree‚ that form when layers of molecules accumulate as the mineral grows. These rings can tell scientists all kinds of things about the environment in which they grew. For example‚ changes in pressure‚ temperature and magma composition can all result in growth rings.Feldspar crystals with growth rings in granodiorite rock near Squamish‚ British Columbia. Natalie Bursztyn‚ CC BY-NDSometimes mineral crystals grow as high pressure and temperatures within the Earth’s crust change rocks from one type to another in a process called metamorphism. This process causes the elements and chemical bonds in the rock to rearrange themselves into new crystal structures. Lots of spectacular crystals grow in this way‚ including garnet‚ kyanite and staurolite.Amazing formsWhen a mineral precipitates from water or crystallizes from magma‚ the more space it has to grow‚ the bigger it can become. There is a cave in Mexico full of giant gypsum crystals‚ some of which are 40 feet (12 meters) long – the size of telephone poles.Especially showy mineral crystals are also valuable as gemstones for jewelry once they are cut into new shapes and polished. The highest price ever paid for a gemstone was $71.2 million for the CTF Pink Star diamond‚ which went up for auction in 2017 and sold in less than five minutes.Hello‚ curious kids&;#33; Do you have a question you’d like an expert to answer&;#63; Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name‚ age and the city where you live.And since curiosity has no age limit – adults‚ let us know what you’re wondering‚ too. We won’t be able to answer every question‚ but we will do our best.Natalie Bursztyn‚ Lecturer in Geosciences‚ University of MontanaThis article is republished from The Conversation under a Creative Commons license. Read the original article.

Most metal elements melt at temperatures of hundreds of degrees‚ but for mercury that is -38.9° C (-38.0° F). So why is this metal different from all others&;#63; It’s all about the outer electrons and a combination of factors that make them bond unusually poorly.The first thing to note is that the title question may not be entirely accurate. There may be two transuranic elements‚ which don’t appear in nature because they decay far too quickly to have survived from their creation in supernovae or kilonovae that are liquid at room temperature. The same short half-lives that mean they have to be produced artificially means we don’t get much time to study them. Copernicium and Flerovium are suspected of being liquid at room temperature‚ but since one lasts seconds before decaying‚ and the other even less‚ there’s a fair degree of uncertainty about this. We certainly haven’t been making a lot of either to study.Leaving these curiosities aside‚ mercury stands out among stable elements. At the simplest level‚ the reason is that mercury’s outermost electrons don’t bond to very strongly‚ weakening the pull between one mercury atom and another. That weakness means that as soon as mercury picks up even quite a modest amount of energy the organization of a solid breaks down and the atoms start moving around more freely.Another way to look at this is that when atoms bond together some of their kinetic energy is converted to the energy of the bond. There’s so little energy in mercury’s bonds with itself that it doesn’t take a lot of movement to break them apart. Since at the atomic level the random kinetic energy amounts to heat‚ mercury doesn’t need to be warm‚ let alone hot‚ to become liquid‚ but other metals‚ with more energy stored in their bonds‚ do. Mercury’s liquid status was known more than three thousand years ago‚ but it’s not something we would have predicted had the element only been discovered as the periodic table was being filled in. Most familiar liquids have quite low density‚ so encountering a liquid so far down the periodic table goes quite against our expectations. Its neighbors on the periodic table‚ gold‚ and thallium‚ melt at more than 1000 and 300 degrees centigrade respectively. It is useful though: mercury’s combination of density and being liquid is why it is so well suited to thermometers‚ barometers‚ and measuring blood pressure. So what is it about mercury’s outer electrons that lead to bonding so much weaker than its fellow metals&;#63; It turns out mercury is in a sweet spot on the table where three effects combine. The first is that its outer electron shell is full. It’s much easier for electrons in a partially filled shell to escape‚ becoming part of a fog of valence electrons that hold atoms together. Metals with more easily shared electrons to share around usually have higher melting points‚ certainly far higher than room temperature.Mercury isn’t the only metal with a full shell‚ however‚ so that can’t be the only reason. Both the other two factors cause the outer electrons of affected atoms to stay closer to their nucleus‚ interfering with their capacity to bond with other atoms.Members of the lanthanide series of elements‚ which share mercury’s sixth period on the periodic table‚ experience what is known as “lanthanide contraction”. The electrons of the 4f subshell shell don’t shield electrons further out from the positive charge of the nucleus as much as others‚ causing the outer electrons to be pulled inwards. Consequently‚ most of the elements in period 6 have atomic radii of similar size to those on the period above them‚ leading to much greater density.Moreover‚ mercury’s outer electrons experience a relativistic contraction‚ moving so fast that the effects of approaching the speed of light come into play. This is something that only really matters with heavier elements‚ since the greater mass accelerates the electrons more. Just as the planet mercury moves around the Sun faster than objects further out‚ electrons drawn close to the nucleus travel faster‚ in cases such as mercury fast enough for relativistic effects to matter.The combination of these two effects interferes with the bonding between mercury atoms. Besides keeping it liquid at room temperature‚ they ensure that when heated to the point that it forms a gas mercury atoms don’t pair up‚ like most elemental gases (think H2‚ O2 or N2). Instead‚ mercury atoms keep to themselves like the noble gases.

Antidepressant drugs have unfairly been the target of suspicion and stigma over the years‚ and there’s no doubt that for some people they can have life-changing effects. There are many different types‚ and they’re not only used to treat depression‚ so let’s break down what the latest science says about these medications.What conditions are antidepressants used for&;#63;Antidepressants are some of the most widely prescribed drugs‚ used by millions of people every day – but not all of these people will have a diagnosis of depression.Although depression is the most common condition these drugs are used for‚ they’re also often part of treatment for other mental health conditions like anxiety‚ post-traumatic stress disorder‚ and obsessive-compulsive disorder.Certain antidepressants – we’ll come on to the different classes in a minute – are also prescribed to treat chronic pain. People with conditions such as complex regional pain syndrome‚ trapped nerves‚ and neuropathic pain due to multiple sclerosis‚ can benefit from the use of specific antidepressants where traditional painkillers have not worked.Doctors may also try antidepressants for patients with non-neuropathic chronic pain‚ such as fibromyalgia‚ but some are moving away from this in light of evidence – such as a 2023 Cochrane review – that they may be no better than a placebo.And there’s another less obvious use for antidepressants. According to the UK’s National Health Service‚ some kids may be treated with antidepressants to help deal with bedwetting‚ as they can relax the muscles of the bladder and decrease the urge to urinate.What classes of antidepressants are there&;#63;SSRIs and SSNIsIf you’re diagnosed with depression and are offered the option of medication‚ the first drug your doctor will suggest will likely be an SSRI – a selective serotonin reuptake inhibitor. You may have heard some of the brand names of these drugs before‚ like Lexapro (escitalopram)‚ Prozac (fluoxetine)‚ and Zoloft (sertraline).Aside from having peculiar effects on fish‚ SSRIs work by stopping the transport of serotonin out of synapses‚ the spaces between neurons where messages pass‚ thereby increasing the amount of serotonin hanging around in the brain. A longstanding hypothesis in psychiatry states that low serotonin levels are partly to blame for depression.Although more recent research indicates that low serotonin alone may not be enough to cause depression in the first place‚ it does seem to play a role in relapses for those with the condition‚ so SSRIs will most likely remain a key part of the psychiatrist’s toolkit for some time to come.That doesn’t mean we can’t update them‚ though. There’s a newer class of drugs that work similarly to SSRIs‚ called serotonin-norepinephrine reuptake inhibitors (SNRIs). As well as helping boost serotonin levels‚ SNRIs also increase the levels of another neurochemical‚ norepinephrine (also called noradrenaline). Some examples of these drugs include venlafaxine and duloxetine – incidentally‚ one of the few that the 2023 Cochrane review found does seem to have some efficacy for non-neuropathic pain.While SSRIs and SNRIs are similar‚ patients may find the side effects of one class more difficult to tolerate than the other. And even within each class‚ the drugs vary in terms of the nuances of how they work in the body and how often you need to take them. Finding the best drug for each person is often a matter of trial and error.TCAsTricyclic antidepressants (TCAs) first came to market in the US in 1959‚ but since the advent of SSRIs‚ they’ve been considered a second-line treatment for depression. Drugs in this class include amitriptyline and imipramine‚ the first to be developed.The “tricyclic” refers to the three rings of atoms these drugs have in their chemical structures. Like SNRIs‚ they also work by blocking the uptake of serotonin and norepinephrine. TCAs have a low therapeutic index‚ meaning that even a small overdose could lead to dangerous symptoms. There’s also some evidence that TCAs tend to cause more side effects than SSRIs and are less well tolerated by patients overall.TCAs are the class of antidepressants that are usually prescribed for neuropathic pain‚ but the evidence on their efficacy is mixed. A 2015 Cochrane review looking specifically at amitriptyline found that it “probably does give really good pain relief” to a minority of people‚ so again it's likely to be a process of trial and error when searching for the best medications for a particular patient.Other classesThere are other antidepressants that doctors may turn to in specific cases‚ such as when other treatments have not worked.Monoamine oxidase inhibitors (MAOIs) are one example. Although they were the first antidepressants to be discovered‚ they have been used less and less as alternative drugs have been developed. A big reason for this is that they can interact with lots of other medications and certain foods. The symptoms of these interactions can be life-threatening for patients‚ but also tricky to spot for medical professionals.Some examples of MAOIs are selegiline and isocarboxazid. They work by targeting the enzyme monoamine oxidase‚ stopping it from breaking down serotonin‚ norepinephrine‚ and dopamine.There are also various drugs that can be classed as “atypical antidepressants”‚ which work in a variety of ways. But for all of these‚ the goal remains to keep as much serotonin‚ norepinephrine‚ and to a lesser extent dopamine‚ in the brain for as long as possible.    Why do some antidepressants take so long to kick in&;#63;One of the difficulties faced by patients when they start taking antidepressants is that they can take several weeks to start working. It’s a conundrum that has plagued the medical establishment.Some have argued this is evidence that the serotonin hypothesis is flawed‚ and that SSRIs only work in some people because they’re doing something else in the brain that we’ve not fully understood yet.Others have suggested that the lag is due to the brain’s homeostatic systems rebalancing things after an initial spike in serotonin when someone starts to take an SSRI. The brain responds by decreasing the production of the neurotransmitter for a time‚ meaning there’s no net increase in serotonin for several weeks while things settle down.But last year‚ one group of scientists put forward a new idea. Their study looked at the effects of one SSRI‚ escitalopram‚ in 32 people without any history of mental health disorders. After taking the drug or a placebo for three to five weeks‚ positron emission tomography (PET) scans revealed a time-dependent increase in new synapses forming in certain areas of the brain.Commenting on the study‚ cognitive neuroscientist Jonathan Roiser‚ who was not involved in the work‚ told Wired: “It's a different perspective to what's come before. It gives the additional weight to this idea that you need the cumulative changes over time in order to shift the environment to be more positive‚ which can then explain how people are then going to recover from depression.”The study was small and included only healthy people‚ so it’s too soon to draw broad conclusions yet. The authors told Wired that the next phase of their work is already underway‚ including studies on people with depression‚ so hopefully‚ more pieces of this puzzle will soon be falling into place.What’s the latest research into antidepressants&;#63;In the meantime‚ other exciting research is opening up the possibility of alternative antidepressant medications.One of the newest drugs on the block is esketamine – and if you’re thinking that name sounds familiar‚ you’d be right. Esketamine has a similar structure to ketamine‚ and its approval for use in treatment-resistant depression sparked excitement and controversy in equal measure.Esketamine is given in the form of a nasal spray. The drug kicks in quickly‚ orders of magnitude faster than an SSRI‚ so it’s designed to complement traditional medications by filling the gap until they start to work.Some scientists are also working on new compounds that refine our existing treatments even further. In 2022‚ a study reported on a drug called ZZL-7‚ which targets the serotonin system but – crucially – seems to be able to do so more quickly. That study was only on mice‚ however‚ so it’s a long way off use in human patients.Another big‚ exciting frontier in this field is the world of psychedelics. Psilocybin‚ the stuff that puts the magic in magic mushrooms‚ has been showing great potential for the most difficult-to-treat depression cases. How it works is still a matter of some debate‚ but now these drugs are becoming more accessible‚ both for research purposes and limited therapeutic uses‚ our understanding of them can only increase.    Drugs are not the only treatment option for depression; but with so many people around the world taking these medications every day‚ it’s good to be informed about what they are‚ how they work‚ and how this landscape could change in the coming years.All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text‚ images‚ and links may be edited‚ removed‚ or added to at a later date to keep information current. The content of this article is not intended to be a substitute for professional medical advice‚ diagnosis‚ or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.