There is no denying the importance of sleep. Everyone feels better after a good night of sleep, and lack of sleep can have profoundly negative effects on both the body and the brain. So what can be done to substitute for a lack of sleep? Put another way, how can you get less sleep and still perform at your peak? As a psychologist who studies the ways in which sleep benefits memory, I’m also interested in how sleep deprivation harms memory and cognition. After some initial research on sleep deprivation and false confessions, my students at Michigan State University’s Sleep and Learning Lab and ...
A recent neuroimaging study has found that adolescents displaying heightened brain activity in response to emotionally charged tasks in the right inferior occipital gyrus, a brain region responsible for processing visual stimuli, tended to exhibit lower distress tolerance and increased levels of depressive symptoms two years later. The study was published in Psychiatry Research: Neuroimaging. Distress tolerance, denoting the capacity to endure and effectively manage emotional distress, discomfort, or pain without resorting to harmful behaviors or becoming overwhelmed, is a pivotal psychologica...
When people notice new things in their environment, it tends to help them remember things better afterward. However, new research published in the Journal of Psychopathology and Clinical Science indicates that this “novelty boost” in memory performance is reduced among those with paranoid tendencies. The new study was motivated by the desire to better understand the relationship between memory impairment and psychotic-like symptoms, particularly focusing on paranoia, in individuals across the psychosis spectrum. Memory impairment is a well-documented feature of psychosis disorders, including s...
Fire devastates communities and families, and it makes identification of victims challenging. In the aftermath of the wildfire that swept through Lahaina, Hawaii, officials are collecting DNA samples from relatives of missing persons in the hope that this can aid in identifying those who died in the fire.
But how well does DNA hold up under such extreme conditions, and what is the best way to recover DNA from fire victims?
I am an anthropological geneticist who studies degraded DNA in archaeological and forensic contexts. My research group applies ancient DNA and forensic analysis methods to optimize DNA recovery from burned bones. Retrieving DNA from severely burned remains in order to identify victims is a particular challenge.
Forensic DNA analysis
In a typical forensic investigation, DNA is extracted from a sample – whether some blood, pieces of tissue or bone – collected from the scene of the disaster or crime. This process chemically separates the DNA from other components of cells within the sample, such as proteins, and purifies it.
This DNA is used as a template for polymerase chain reaction, or PCR, analysis, a method that is essentially the Xerox copier of molecular biology. Even if there are only a few cells present in the sample, PCR can amplify those DNA molecules into thousands or millions of copies. This creates a sufficient amount of DNA for subsequent tests.
DNA analysis can help identify victims by comparing genetic similarities between people.
In forensics, the specific DNA targeted in PCR is usually a set of highly repetitive markers called microsatellites, or short tandem repeats. Law enforcement agencies around the world use specific sets of these markers for identification purposes. In the U.S., forensic analysts target 20 of these DNA repeats. Each person has two unique alleles, or genetic variants, at each of these markers, and these alleles are uploaded to the FBI’s Combined DNA Index System database to identify matches.
DNA taken from the relatives of missing people will likely be analyzed for short tandem repeat markers and their allele profiles uploaded to the Relatives of Missing Persons index within the database. The expectation is that victims and their biological relatives share a percentage of alleles for these markers. For example, parents and children share 50% of their alleles, since a child inherits half of their DNA from each parent.
Challenge of degraded DNA
In forensic contexts, the time between death and DNA sampling is usually short enough that the DNA is often still in fairly good shape, both in terms of quantity and quality. However, DNA is often not found in ideal conditions after a disaster.
Time and the elements take their toll. After death, the process of decomposition releases enzymes that can cleave or damage DNA, and additional damage occurs over time depending on the environment in which the body is found. DNA also degrades faster in warm, wet, acidic environments and slower in colder, drier environments that are more pH neutral or slightly basic.
In addition, DNA preservation may vary considerably among the tissues, bones and teeth recovered. For example, researchers found that DNA identification of victims of the World Trade Center attacks in 2001 was most successful when using bones of the feet and legs, compared with bones from the head and torso.
DNA damage can take different forms. Nicks and breaks in the DNA make it difficult to analyze. Chemical modification of the DNA can result in changes to the original sequence or make it unreadable. This includes changes to the building blocks of DNA called nucleotides that make up an identifiable sequence. For example, exposure to water can cause a chemical reaction called deamination that changes the nucleotide cytosine such that it appears to be the nucleotide thymine upon analysis. Exposures to other chemicals or UV light can cause cross-linking, which essentially ties the DNA into knots. As a result, the PCR enzymes used to copy or read the DNA sequence can’t move linearly along the DNA strand.
Exposure to intense and extended fires can make victim identification through DNA analysis difficult. AP Photo/Jae C. Hong
Applying methods from archaeology
Researchers encounter similar issues in handling degraded genetic material when analyzing the DNA of ancient remains that are thousands of years old. To address these challenges, forensic geneticists and ancient DNA researchers like me employ a number of tricks to optimize DNA retrieval.
First, we tend to target dense bone or teeth for sampling, since they are more impervious to the environment. We also use DNA extraction methods that enhance the recovery of short fragments of DNA.
Second, we use PCR to amplify even shorter genetic markers, including mini-short tandem repeats, or sections of the mitochondrial genome. Mitochondria are structures within each cell that produce energy, and each one has its own DNA. Mitochondrial DNA is passed down from mother to child and can be found in hundreds of copies within each mitochondrion, which make it easier to recover and analyze. However, mitochondrial DNA may not provide sufficient information for identification, since people who are maternally related, even very distantly, will share the same sequence.
Researchers are also testing newer methods of DNA analysis common in the ancient DNA field for forensic purposes. For example, special enzymes can remove chemically modified nucleotides, such as deaminated cytosines, to prevent misreading of the DNA sequence. Researchers can also use DNA baits to “fish” for specific sequences. This method of targeted enrichment can recover very small fragments that can be used to piece together the full genetic sequence.
DNA analysis of burned remains
For fire victims, particularly those caught in intense, extended fires, the DNA may be highly fragmented, making analysis difficult. High temperatures cause bonds between molecules, including nucleotides, to break. This results in fragmentation and ultimately destruction of the DNA.
Because hard tissue – bones and teeth – are often all that remains after a fire, forensic researchers have studied how bone characteristics such as color and composition change with temperature. My research team used this information to classify the level of burning that human bone samples have been subjected to.
In investigating DNA preservation in those samples, we found that there is a significant point of DNA degradation when bones reached temperatures between 662 degrees Fahrenheit (350 degrees Celsius) and 1,022 F (550 C). For comparison, commercial cremation is 1,400 to 1,600 F (760 to 871 C) for 30 to 120 minutes, and vehicle fires typically reach 1,652 degrees F (900 C) but can last a shorter period of time.
Survivors of the Lahaina wildfires, which began on Aug. 8, 2023, walk through the aftermath. AP Photo/Rick Bowmer
Our team also found that the likelihood of generating high-quality short tandem repeat data or mitochondrial DNA sequence data, whether using forensic or ancient DNA methods, decreases significantly at temperatures greater than 1,022 F (550 C).
In sum, as temperature and exposure time increase, the amount of remaining DNA decreases. This leads to only partial DNA profiles, which can limit analysts’ ability to match a victim to a relative with high statistical certainty or prevent results altogether.
DNA evidence is not the only method used for identification. Investigators combine DNA with other evidence – such as dental, skeletal and contextual information – to identify a victim conclusively. Together, this information hopefully will help bring closure for families and friends.
French novelist Jules Verne delighted 19th-century readers with the tantalizing notion that a journey to the center of the Earth was actually plausible.
Since then, scientists have long acknowledged that Verne’s literary journey was only science fiction. The extreme temperatures of the Earth’s interior – around 10,000 degrees Fahrenheit (5,537 Celsius) at the core – and the accompanying crushing pressure, which is millions of times more than at the surface, prevent people from venturing down very far.
Still, there are a few things known about the Earth’s interior. For example, geophysicists discovered that the core consists of a solid sphere of iron and nickel that comprises 20% of the Earth’s radius, surrounded by a shell of molten iron and nickel that spans an additional 15% of Earth’s radius.
That, and the rest of our knowledge about our world’s interior, was learned indirectly – either by studying Earth’s magnetic field or the way earthquake waves bounce off different layers below the Earth’s surface.
But indirect discovery has its limitations. How can scientists find out more about our planet’s deep interior?
Planetary scientists like me think the best way to learn about inner Earth is in outer space. NASA’s robotic mission to a metal world is scheduled for liftoff on Oct. 5, 2023. That mission, the spacecraft traveling there, and the world it will explore all have the same name – Psyche. And for six years now, I’ve been part of NASA’s Psyche team.
It’s a mission of ‘firsts.’
About the asteroid Psyche
Asteroids are small worlds, with some the size of small cities and others as large as small countries. They are the leftover building blocks from our solar system’s early and violent period, a time of planetary formation.
Although most are rocky, icy or a combination of both, perhaps 20% of asteroids are worlds made of metal, and similar in composition to the Earth’s core. So it’s tempting to imagine that these metallic asteroids are pieces of the cores of once-existing planets, ripped apart by ancient cosmic collisions with each other. Maybe, by studying these pieces, scientists could find out directly what a planetary core is like.
Psyche is the largest-known of the metallic asteroids. Discovered in 1852, Psyche has the width of Massachusetts, a squashed spherical shape reminiscent of a pincushion, and an orbit between Mars and Jupiter in the main asteroid belt. An amateur astronomer can see Psyche with a backyard telescope, but it appears only as a pinpoint of light.
An artist’s rendition of Psyche, a spectacular metallic world.
About the Psyche mission
In early 2017, NASA approved the US$1 billion mission to Psyche. To do its work, there’s no need for the uncrewed spacecraft to land – instead, it will orbit the asteroid repeatedly and methodically, starting from 435 miles (700 kilometers) out and then going down to 46 miles (75 km) from the surface, and perhaps even lower.
Once it arrives in August 2029, the probe will spend 26 months mapping the asteroid’s geology, topography and gravity; it will search for evidence of a magnetic field; and it will compare the asteroid’s composition with what scientists know, or think we know, about Earth’s core.
The central questions are these: Is Psyche really an exposed planetary core? Is the asteroid one big bedrock boulder, a rubble pile of smaller boulders, or something else entirely? Are there clues that the previous outer layers of this small world – the crust and mantle – were violently stripped away long ago? And maybe the most critical question: Can what we learn about Psyche be extrapolated to solve some of the mysteries about the Earth’s core?
NASA’s Psyche spacecraft, undergoing final tests in a clean room at a facility near Florida’s Kennedy Space Center. NASA/Frank Michaux
About the spacecraft Psyche
The probe’s body is about the same size and mass as a large SUV. Solar panels, stretching a bit wider than a tennis court, power the cameras, spectrometers and other systems.
A SpaceX Falcon Heavy rocket will take Psyche off the Earth. The rest of the way, Psyche will rely on ion propulsion – the gentle pressure of ionized xenon gas jetting out of a nozzle provides a continuous, reliable and low-cost way to propel spacecraft out into the solar system.
The journey, a slow spiral of 2.5 billion miles (4 billion km) that includes a gravity-assist flyby past Mars, will take nearly six years. Throughout the cruise, the Psyche team at NASA’s Jet Propulsion Laboratory in Pasadena, California, and here at Arizona State University in Tempe, will stay in regular contact with the spacecraft. Our team will send and receive data using NASA’s Deep Space Network of giant radio antennas.
Even if we learn that Psyche is not an ancient planetary core, we’re bound to significantly add to our body of knowledge about the solar system and the way planets form. After all, Psyche is still unlike any world humans have ever visited. Maybe we can’t yet journey to the center of the Earth, but robotic avatars to places like Psyche can help unlock the mysteries hidden deep inside the planets – including our own.
One particularly ingenious image showcases an orca posed as a sickle crossed with a hammer. The cheeky caption reads, “Eat the rich,” a nod to the orcas’ penchant for sinking lavish yachts.
Memes conjure her in a beret like the one donned by socialist revolutionary Ché Guevara. In one caption, she proclaims, “Accept our existence or expect resistance … an otter world is possible.”
My scholarship centers on animal-human relations through the prism of social justice. As I see it, public glee about wrecked surfboards and yachts hints at a certain flavor of schadenfreude. At a time marked by drastic socioeconomic disparities, white supremacy and environmental degradation, casting these marine mammals as revolutionaries seems like a projection of desires for social justice and habitable ecosystems.
A glimpse into the work of some political scientists, philosophers and animal behavior researchers injects weightiness into this jocular public dialogue. The field of critical animal studies analyzes structures of oppression and power and considers pathways to dismantling them. These scholars’ insights challenge the prevailing view of nonhuman animals as passive victims. They also oppose the widespread assumption that nonhuman animals can’t be political actors.
So while meme lovers project emotions and perspectives onto these particular wild animals, scholars of critical animal studies suggest that nonhuman animals do in fact engage in resistance.
Nonhuman animal protest is everywhere
Are nonhuman animals in a constant state of defiance? I’d answer, undoubtedly, that the answer is yes.
The entire architecture of animal agriculture attests to animals’ unyielding resistance against confinement and death. Cages, corrals, pens and tanks would not exist were it not for animals’ tireless revolt.
Even when hung upside down on conveyor hangars, chickens furiously flap their wings and bite, scratch, peck and defecate on line workers at every stage of the process leading to their deaths.
If they didn’t mind having their infants permanently taken from their sides, dairy cows wouldn’t need to be blinded with hoods so they don’t bite and kick as the calves are removed; they wouldn’t bellow for weeks after each instance. I contend that failure to recognize their bellowing as protest reflects “anthropodenial” – what ethologist Frans de Waal calls the rejection of obvious continuities between human and nonhuman animal behavior, cognition and emotion.
The prevalent view of nonhuman animals remains that of René Descartes, the 17th-century philosopher who viewed animals’ actions as purely mechanical, like those of a machine. From this viewpoint, one might dismiss these nonhuman animals’ will to prevail as unintentional or merely instinctual. But political scientist Dinesh Wadiwel argues that “even if their defiance is futile, the will to prefer life over death is a primary act of resistance, perhaps the only act of dissent available to animals who are subject to extreme forms of control.”
Philosopher Fahim Amir suggests that depression among captive animals is likewise a form of emotional rebellion against unbearable conditions, a revolt of the nerves. Dolphins engage in self-harm like thrashing against the tank’s walls or cease to eat and retain their breath until death. Sows whose body-sized cages impede them from turning around to make contact with their piglets repeatedly ram themselves into the metal struts, sometimes succumbing to their injuries.
Critical animal studies scholars contend that all these actions arguably demonstrate nonhuman animals’ yearning for freedom and their aversionto inequity.
Sharing memes that cheer on wild animals is one thing. But there are more substantive ways to demonstrate solidarity with animals.
Legal scholars support nonhuman animals’ resistance by proposing that their current classification as property should be replaced with that of personhood or beingness.
Nonhuman animals including songbirds, dolphins, elephants, horses, chimpanzees and bears increasingly appear as plaintiffs alleging their subjection to extinction, abuse and other injustices.
Citizenship for nonhuman animals is another pathway to social and political inclusion. It would guarantee the right to appeal arbitrary restrictions of domesticated nonhuman animals’ autonomy. It would also mandate legal duties to protect them from harm.
Everyday deeds can likewise convey solidarity.
Boycotting industries that oppress nonhuman animals by becoming vegan is a powerful action. It is a form of political “counter-conduct,” a term philosopher Michel Foucault uses to describe practices that oppose dominant norms of power and control.
Otter 841 is the wild sea otter off Santa Cruz, California, who some observers suspect has had it with surfers in her turf.
Might an ‘otter world’ be possible?
I believe quips about the marine mammal rebellion reflect awareness that our human interests are entwined with those of nonhuman animals. The desire to achieve sustainable relationships with other species and the natural world feels palpable to me within the memes and media coverage. And it’s happening as human-caused activity makes our shared habitats increasingly unlivable.
Solidarity with nonhuman animals is consistent with democratic principles – for instance, defending the right to well-being and opposing the use of force against innocent subjects. Philosopher Amir recommends extending the idea that there can be no freedom as long as there is still unfreedom beyond the species divide: “While we may not yet fully be able to picture what this may mean, there is no reason we should not begin to imagine it”.
The findings of a new study call into question the widely held belief that facial masculinity is a reliable indicator of a man’s potential for paternal involvement. The authors of the study did not find a significant relationship between facial masculinity and actual self-reported paternal involvement or perceived paternal involvement. This implies that facial masculinity may not consistently signal higher or lower levels of paternal investment in a reliable manner. The research, published in Adaptive Human Behavior and Physiology, provides insights into the complex interplay between facial ma...
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The idea of space-based solar power (SBSP) – using satellites to collect energy from the sun and “beam” it to collection points on Earth – has been around since at least the late 1960s. Despite its huge potential, the concept has not gained sufficient traction due to cost and technological hurdles.
Can some of these problems now be solved? If so, SBSP could become a vital part of the world’s transition away from fossil fuels to green energy.
We already harvest energy from the sun. It’s collected directly through what we generally call solar power. This comprises different technologies such as photovoltaics (PV) and solar-thermal energy. The sun’s energy is also gathered indirectly: wind energy is an example of this, because breezes are generated by uneven heating of the atmosphere by the sun.
But these green forms of power generation have limitations. They take up lots of space on land and are limited by the availability of light and wind. For example, solar farms don’t collect energy at night and gather less of it in winter and on cloudy days.
PV in orbit won’t be limited by the onset of night. A satellite in geostationary orbit (GEO) – a circular orbit around 36,000 km above the Earth – is exposed to the Sun for more than 99% of the time during a whole year. This allows it to produce green energy 24/7.
GEO is ideal for when energy needs to be sent from the spacecraft to an energy collector, or ground station, because satellites here are stationary with respect to the Earth. It’s thought that there’s 100 times more solar power available from GEO, than the estimated global power demands of humanity by 2050.
Transferring energy collected in space to the ground requires wireless power transmission. Using microwaves for this minimizes the energy lost in the atmosphere, even through cloudy skies. The microwave beam sent by the satellite will be focused towards the ground station, where antennas convert the electromagnetic waves back into electricity. The ground station will need to have a diameter of 5 km, or more at high latitudes. However, this is still smaller than the areas of land needed to produce the same amount of power using solar or wind.
Evolving concepts
Numerous designs have been proposed since the first concept by Peter Glaser in 1968.
Drawing depicting Peter Glaser’s satellite-based method for converting solar radiation to electrical power. U.S. Patent Office
In SBSP, the energy is converted several times (light to electricity to microwaves to electricity), and some of it is lost as heat. In order to inject 2 gigawatts (GW) of power into the grid, about 10 GW of power will need to be collected by the satellite.
A recent concept called CASSIOPeiA consists of two 2km-wide steerable reflectors. These reflect the sunlight into an array of solar panels. These power transmitters, approximately 1,700 meters in diameter, can be pointed at the ground station. It is estimated that the satellite could have a mass of 2,000 tonnes.
Another architecture, SPS-ALPHA, differs from CASSIOPeiA in that the solar collector is a large structure formed by a huge number of small, modular reflectors called heliostats, each of which can be independently moved. They are mass-produced to reduce cost.
Artistic impression of the SPS-ALPHA concept. NASA/John Mankins
In 2023, scientists at Caltech launched MAPLE, a small-scale satellite experiment which beamed a tiny amount of power back to Caltech. MAPLE proved the technology could be used to deliver power to Earth.
National and international interest
SBSP could play a crucial role to meet the UK’s net-zero target by 2050 – but the government’s current strategy does not include it. An independent study found that SBSP could generate up to 10GW of electricity by 2050, one-quarter of the UK’s current demand. SBSP provides a secure and stable energy supply.
It will also create a multi billion-pound industry, with 143,000 jobs across the country. The European Space Agency is currently evaluating the viability of SBSP with its SOLARIS initiative. This could be followed by a full development plan for the technology by 2025.
Othercountries have recently announced the intention to beam power to Earth by 2025, moving to larger systems within the next two decades.
A massive satellite
If the technology is ready, why is SBSP not being used? The main limit is the enormous amount of mass that needs to be launched into space, and its cost per kilogram. Companies such as SpaceX and Blue Origin are developing heavy-lift launch vehicles, with a focus on reusing parts of those vehicles after they have flown. This can bring the cost of the venture down by 90%.
Even using SpaceX’s Starship vehicle, which can launch 150 tonnes of cargo into low Earth orbit, the SBSP satellite will require hundreds of launches. Some components, such as long structural trusses – structural elements designed to span long distances – could be 3D-printedin space.
Challenges and risks
An SBSP mission will be challenging – and risks still need to be fully assessed. While the electricity produced is fully green, the impact of the pollution from hundreds of heavy-lift launches is difficult to predict.
Additionally, controlling such a large structure in space will require substantial amounts of fuel, which involves engineers working with sometimes very toxic chemicals. The photovoltaic solar panels will be affected by degradation, reducing efficiency over time from 1% to 10% per year. However, servicing and refuelingcould be used to extend the satellite’s lifetime almost indefinitely.
A beam of microwaves powerful enough to reach the ground could also harm anything that got in the way. For safety, then, the power density of the beam will have to be restricted.
The challenge of building platforms like this in space may seem daunting, but space-based solar power is technologically feasible. To be economically viable, it requires large-scale engineering, and therefore long-term and decisive commitment from governments and space agencies.
But with all that in place, SBSP could make a fundamental contribution to delivering net zero by 2050 with sustainable, clean energy from space.
