SCIENCE

Mirror Supernova Provides Surprising Estimation of Cosmic Growth

Published

10 hours ago

May 11, 2023

How fast is the universe expanding? It depends who you ask. Take a look at the relatively nearby stars and galaxies surrounding us in space, and you’ll get a specific number for that value, known as the Hubble constant. But look into a much more distant universe and you get a slightly different number. This discrepancy, known as the Hubble voltage, is small but has serious consequences. The stress may simply be caused by errors in our measurements, or it may indicate fundamental gaps in our understanding of cosmic structure. Admittedly, even without any tension, there are deep mysteries associated with the rate of expansion of the universe, namely the fact that it is accelerated by dark energy, an as-yet unexplained force about which we know almost nothing. Now, a new measurement of the Hubble constant, made by observing the mirror image of a distant exploding star or supernova, complicates matters further.

In the study published today in the magazine The science, Patrick Kelly of the University of Minnesota and colleagues used the time delay from a distant supernova known as Refsdal to measure the Hubble constant. They obtained an expansion rate of 66.6 km/s per million parsecs (km/s/Mpc), or 66.6 km/s over 3.26 million light years, with an error of 1.5%. (The previous supernova study, conducted in 2017, reached similar result but with much greater statistical uncertainty.)

This number – 66.6 km/s/Mpc – is oddly at odds with other supernova measurements in the so-called local universe. They tend to give a higher value for the Hubble constant: about 73 km/s/Mpc. However, the value of 66.6 km/s/Mpc is strikingly similar to measurements of the Hubble constant from much more distant sources in the “early” universe, which give values around 67 km/s/Mpc. “We have to agree with supernova measurements, but we don’t,” Kelly says. “And they can’t both be right.”

The Hubble constant can be measured in several ways. As for the local universe, most of them rely on various standard candles – certain types of supernovae and other astrophysical objects that have a known, barely changing intrinsic brightness, which makes it easier to determine their distances and movements relative to us. Measurements of several types of standard candles can be linked together to allow astronomers to measure the Hubble constant at ever greater distances, with each standard candle being one “rung” on the so-called “cosmic distance ladder”. But the cosmic distance begins to shake the ladder and somersault through truly vast distances. To measure the Hubble constant, which dominated the early universe, researchers mainly use the cosmic microwave background (CMB) — essentially the residual heat from the Big Bang when the universe was barely more than 400,000 years ago a fireball. Sound waves traveling through this cosmic fire imprinted characteristic patterns on the CMB that astronomers can use as standard rulers to chart the subsequent expansion of the universe.

In 1964, Norwegian astrophysicist Sur Refsdal first proposed another way to use supernovae to measure the Hubble constant. If, on its way to Earth, the light of a distant supernova accidentally passes through the gravitational grip of a massive object such as a cluster of galaxies, the light could be “gravitationally lensed” or warped and bent to follow multiple divergent paths to Earth. , some are longer and some are shorter. The end result will be a single supernova appearing several times at slightly shifted positions in the sky, with a delay between each appearance corresponding to the total distance that its light has traveled. Combining such delays with knowing how fast the supernova is moving away from us, obtained by measuring a property called redshift, and the mass of the lensing cluster, would give a value for the Hubble constant.

In November 2014, Kelly, then at UC Berkeley, and colleagues discovered the first known example of such an event, the Refsdal supernova, which occurred about 14 billion light-years from Earth. They correctly predicted the arrival of a lensed image of a supernova that reached our planet after about 360 days, at the end of 2015. Now the team has finally succeeded in using Refsdal to measure the expansion rate of the universe. “It’s different from anything that’s been done before,” Kelly says. To get the value, the team worked in groups that independently evaluated the blind data to come up with an unexpectedly inverted early-universe figure of about 66.6 km/s/Mpc.

The result is a “great addition” to our knowledge of the Hubble constant, says Wendy Friedman, an astronomer at the University of Chicago who specializes in studying the expansion rate of the universe and was not involved in the new paper. “It’s completely independent of any other method.”

Astronomers have used lensing to measure the expansion of the universe before, but with quasars — the extremely bright cores of some galaxies — rather than supernovae. In 2017, a team called H0LiCOW used this method to get the value about 72km/s/mpk. Lenticular quasars are “more numerous” in the sky, which gives this method some advantages, says H0LiCOW leader Sherry Suyu of the Max Planck Institute for Astrophysics in Garching, Germany. But supernovae show more obvious changes in brightness, meaning that the exact time delay of images can be measured more precisely, possibly giving a higher level of accuracy. “You really see this dramatic change,” says Suyu.

But while quasars can shine for millions of years—essentially forever for us—supernovae are short-lived, shining brightly for only a few weeks or months. “You have to be able to find them early on,” Suyu says. “If you miss it, they’re gone.” To date, only a few time-delayed supernovae are known. most recently named H0pe, was discovered by the James Webb Space Telescope (JWST) earlier this year. So while Refsdal is the first such event used to measure the expansion of the universe, it certainly won’t be the last.

If the value of Kelly and his team is confirmed, it would mean that we may need to adjust our best guesses about the nature of dark matter — the mysterious, invisible stuff that seems to give galaxies and clusters of galaxies most of their mass and thus modulates gravitational lensing. . If this is true, Kelly says, their result “implies that there must be an error in our models of dark matter in galaxy clusters.” Updating these models may, in turn, require changes to the so-called standard cosmological model, which suggests that a certain, rather inert, “cold” form of dark matter and a certain type of dark energy work together to drive growth and evolution. galaxies and clusters in space time.

“We don’t yet understand what dark matter and dark energy are,” says Friedman. “Local measurement of the Hubble constant is a way to test this model directly. If it shows that some fundamental piece of physics is missing from the Standard Model, that will be very interesting.”

However, not everyone is convinced that such cosmological cardinal changes are coming. Daniel Skolnick of Duke University says the result’s seemingly small margin of error of 1.5 percent is still big enough in the margins to put it within the range of other local results. “If they got much smaller uncertainties, then everyone would have to stare at themselves in the mirror right now,” says Skolnick, who was not involved in the study. “That would be really confusing because all the local measurements seem to agree with the higher values.”

Finding this out for sure would require studying more time-lag supernovae and establishing their values for the Hubble constant. Such results may come sooner rather than later: JWST is expected to measure H0pe in the coming months, and the upcoming Vera Rubin Observatory in Chile, due to launch next year, should greatly increase the population of known time-delayed supernovae. “We will find many more of these,” Kelly says. “If they are all in favor of a lower value for the Hubble constant, this will increase the controversy. Hopefully we can figure out what the problem is.”

Related Topics:Cosmic Estimation galaxies gravity growth Milky Way Mirror Supernova surprising universe

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SCIENCE

‘No Mow May’ encourages homeowners to help bees by letting their lawns grow

Published

4 hours ago

May 12, 2023

Jan Topete

let it grow

More than 70 cities in the US signed an agreement to ease maintenance rules for property owners in May, as part of a move to feed local bee populations for the upcoming growing season.

called “No mow may”, the initiative began in the United Kingdom and was later adopted by Appleton, Wisconsin, which became the first US city to implement it in 2020. let bee-friendly plants grow in their yards.

“Annoying weeds like clover and dandelions are like bee cheeseburgers,” said Israel Del Toro, an assistant professor of biology at Lawrence University and a city council member in Appleton.

According to Del Toro, Appleton saw the benefits of the bees. Since the start of the project, Appleton’s “No Mow May” lawns have shown a fivefold increase in bee numbers and a threefold increase in bee diversity compared to nearby parklands that were regularly mowed.

Bees are essential pollinators. Bees pollinate every year $15 billion harvest in the US and help farmers produce about third of all the food Americans eat.

But global bee populations are at risk — factors such as habitat loss, overuse of chemical pesticides and herbicides, disease and climate change could negatively impact bees, Del Toro said. globally, 35% invertebrate pollinatorsmainly bees and butterflies, are on the verge of extinction.

“If we can help the bees even a little, and not mow the lawns or give them extra food, that could make a big difference,” Del Toro said.

Without regular lawn mowing, homeowners also reduce the risk of soil damage from ground-nesting bees such as miner bees or leaf cutter bees, according to Relena Ribbons, an assistant professor of geosciences at Lawrence University.

An additional benefit of less mowing is the reduction of local air pollution. Because most lawnmowers run on gasoline, they can emit significant levels of air pollutants such as nitrogen oxides, carbon monoxide, particulate matter and carbon dioxide.

Angela Vanden Elzen, a librarian and lifelong resident of Appleton, said she rarely saw the bees in the city when they were growing.

“No Mow May gives us the opportunity to help our ecosystem effortlessly,” said Vanden Elzen. “I love sharing the project with my kids. It all started with honey bees, and now they have become more tolerant of all creatures, even spiders.”

Vanden Elsen’s seven-year-old daughter, Elora, said she enjoys participating in May Without Braids with her community.

“I’m excited about No Mow May because we feed the bees,” Elora said. “And I love seeing all the bright colors in my front yard and seeing the bees buzzing on the flowers.”

In other cities, residents have expressed concern that their lawns are not mowed. Jo Ann Lytvyn Clinton, Mayor of Orchard Park, New York raised a question attraction of ticks and rodents by neglected lawns. Orchard Park residents are currently debating whether mowing 2-foot by 2-foot areas is enough to stimulate bee populations.

At the University of Minnesota, a bee research group called the Bee Squad recommends practicing “Slow Mow Summer,” a method in which homeowners mow their lawns infrequently in the summer, keeping the grass at a moderately high height. Elaine Evans, a professor at the University of Minnesota and a researcher with the Bee Squad, said this strategy could help provide bees with food throughout the season, not just in May.

Matthew Normansel, an Appleton resident who runs Eden Wild Food, a wild food foraging and education business, said “No Mow May” is an important part of the solution.

“This is the first step towards realizing that our land and property are connected to the environment,” he said. “I don’t think it’s an answer, but it’s the start of an important conversation.”

SCIENCE

Pancreatic cancer vaccine shows promise in small initial trial

Published

5 hours ago

May 11, 2023

Jan Topete

Pancreatic cancer is one of the deadliest forms of cancer for which there are very few effective treatments. But messenger RNA (mRNA) vaccines, known for their ability to prevent COVID, are beginning to show some promise in the fight against deadly cancer. In a recent study, it helped early stage patients with pancreatic cancer who received personalized mRNA cancer vaccine after the operation there was no recurrence of the tumor in a year and a half. The trial, which was described in a study published Wednesday at Naturewhich was small—only 16 patients—and will need to be replicated in larger studies.

“I fully support the results,” says Drew Weissman, director of vaccine research and director of the RNA Innovation Institute at the University of Pennsylvania, a mRNA vaccine pioneer but not involved in the new paper. He adds that “this is not a definitive usability study. Larger studies are needed to determine effectiveness.”

Pancreatic ductal adenocarcinoma, the most common type of pancreatic cancer, has a mortality rate of 88 percent. It is the third leading cause of cancer death in the US and is becoming more common. Surgery is the main form of treatment, but cancer has a 90 percent recurrence rate within seven to nine months. Chemotherapy is only partially effective in delaying relapse. Other treatments, such as immunotherapy, are largely ineffective.

Pancreatic cancer often goes unnoticed until advanced stages, when it is more difficult to treat. One reason for its secretiveness is that it generates relatively few surface proteins called neoantigens that mark it as foreign and elicit an immune response. The scientists noticed that people who survived pancreatic cancer had a stronger response to these T cell neoantigens, a type of immune cell.

In a new study, Vinod Balachandran, an assistant surgeon at Memorial Sloan-Kettering Cancer Center in New York, and colleagues targeted the self-tumor neoantigens of pancreatic cancer patients using mRNA technology, the same technology that was used to create the hugely successful vaccines against COVID. The experimental vaccines used by Balachandran and his colleagues were produced by BioNTech, which developed one of the COVID vaccines with Pfizer. The researchers vaccinated a total of 16 patients. After surgical removal of tumors, they treated patients with mRNA vaccines tailored to each person’s specific cancer, as well as an adjuvant, a substance that enhances the effects of vaccines. Fifteen participants also completed chemotherapy.

Eight of 16 patients developed a strong T-cell response to the vaccines. With a mean follow-up of 18 months after treatment, these people had longer cancer-free survival.

The study was small and included only white patients. And therapy, which is expensive, doesn’t work for all pancreatic cancer patients. Still, experts say it’s a promising development for a disease with such limited treatment options.

SCIENCE

5 best psychological theories of Sigmund Freud

Published

6 hours ago

May 11, 2023

Jan Topete

This article was originally published on May 6, 2022.

When we tell our friends about a crazy dream we had with them, or when we use terms like ego and free association, we are referring to Sigmund Freud.

More than 80 years after his death, Freud’s theories about the human unconscious and how it affects our behavior continue to permeate Western culture. Freud’s pioneering psychological theories, presented to the world at the turn of the 20th century, changed our understanding of the human mind. His theories have influenced not only psychological theory, but also the way we behave in everyday life, in the family and at work. life.

Freud’s psychoanalytic theory

Terms like sleep analysis, free association, Oedipus complexthe Freudian slip and the ubiquitous ego, and id and superegowoven into much of what we do, think and say.

1. Sleep analysis

In modern society, we often talk about our dreams. If you google “dream quotes” there seems to be an endless supply of them. From bestselling author Erma Bombeck’s joke, “It takes a lot of guts to show your dreams to someone else,” to the American rapper and actor, Tupac Shakur lyrics, “Reality is wrong. Dreams are real.” But it is Freud who reveals what a dream is – an alternative reality that we experience when we sleep.

“The interpretation of dreams is the royal road to knowledge of the unconscious activities of the mind,” writes Freud.

Freud’s theory of dreams and his book The Interpretation of Dreams., were revolutionary. Before its publication in 1899, scientists considered dreams to be “meaningless”. Freud believed that dreams were “the disguised fulfillment of repressed childhood desires”.

While popular culture has taken Freud’s theories and applied their meaning – for example, dreams about flying mean that you are subconsciously thinking about ambition – Freud never wrote a dream dictionary. In fact, he shied away from such specifics. He insisted that although dreams are symbolic, they are specific to the individual and cannot be defined in general for the entire society.

2. Free association

Freud’s dream theories directly influenced his free association theory. Based on the theory that dreams and their meanings are individual, Freud allowed his patients to interpret their dreams for themselves, instead of giving them their own opinion. He called his process free association. With each new feature of a dream during a psychoanalytic session, Freud suggested that his patients relax and—to use a modern term—spit out what they thought it meant. Patients threw out ideas as they came, no matter how trivial they might be.

3. Reports on Freud

One of the most popular phrases from Freud’s theories: Freudian slip. He believed that a “slip of the tongue” – when we say something that we are not going to say – shows what we are thinking, subconsciously. Freud presented his theory of the Freudian slip in his 1901 book. Psychopathology of everyday life, and suggested that these verbal (and sometimes written) errors were rooted in “unconscious urges” and “unexpressed desires”. In addition, Freud believed that the inability to remember something – for example, someone’s address or name – is due to our need or desire to suppress it. Modern science has yet to explain why Freudian slips happen.

4. Oedipus complex, penis envy and womb envy

Experts believe Oedipus complex, psychosexual theory, as Freud’s most controversial theory. According to Freud, this is an unconscious desire that begins at the phallic stage of development, between the ages of three and six. The child is sexually attracted to its parent of the opposite sex and is jealous of its parent of the same sex.

Popular culture uses the Oedipus complex as a general term for the phase for both boys and girls. But Freud postulated that boys experience an Oedipus complex and girls an Electra complex. This is when a girl unconsciously becomes sexually attached to her father and is hostile to her mother.

Freud believed that the Oedipus complex was “the central phenomenon of the sexual period of early childhood”, but there is no scientific evidence to support his theory.

“Penis envy” grew out of Freud’s theory of the Oedipus complex, and Freud published it in 1908. Freud believed that a woman’s realization that she does not have a penis leads to intense envy, which underlies female behavior.

“Freud claimed that the only way to overcome this penis envy was to have a child of his own, and even went so far as to suggest that he wanted a male child in his efforts to gain a penis,” the researcher writes. British Psychological Society. Psychoanalyst Karen Horney, a contemporary of Freud whose theories led to the feminist psychology movement, saw penis envy as purely symbolic.

Horney postulated that envy, not of the phallus itself, but of the envy of the penis, had more to do with a woman’s position in society and “the desire for social prestige and position that men experience.” Thus, women felt inferior because of the freedom and social status they lacked because of their gender, and not because of their literal lack of a phallus,” the author writes. British Psychological Society.

In addition, Horney introduces the term “womb envy” and explains that men are negatively affected by their inability to have children and envy the “biological functions of the female sex”, including breastfeeding and pregnancy.

5. Ego, Id and Superego

Somebody think human psyche as the most enduring psychoanalytic theory in Freud’s career. Freud published his personality theory in 1923, which hypothesizes that the human psyche is divided into three parts – the ego, the id, and the superego. And they all develop at different stages of our lives. It is important to note that Freud believed that these are not physical objects in our brains, but rather “systems”.

While the word “ego” is used much more frequently in popular culture than “id” and “superego”, the three are related. According to Freud, the id is the most primitive part of the human psyche. This is the basis of our sexual and aggressive urges. The superego is our moral compass, and the ego is the judge, if you will, between the pulls of the id and the superego.

Freud’s psychological theories remain in our subconscious and consciousness

The next time you wake up from a strange dream that you can tell your best friend in detail, he will respond: “Oh, snakes? This dream is all about penis envy.” Or your boss yells at you and you mutter under your breath, “Too ego.” Or you are killing time on a long car ride and throwing away words and free associations – you have to thank Freud. And, if you’re looking for a reason to pay tribute to Freud and all of his contributions to our folk, pop culture and therapy, consider raising a toast to the father of psychoanalysis. He was born on May 6, 1856.