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ID	6
Conference Title	4Th Annual International Conference On Language, Literature &Amp; Linguistics (L3 2015)
Field	Language
Country	Singapore
Organizer	Global Science and Technology Forum
URL	http://www.l3-conference.org/index.html
Date	2015/06/08

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close up of cells lining the human gut, showing multicolored bacterial cells floating just above the gut cells — Scientists are looking to the gut microbiome for clues about why colorectal cancer is on the rise in young people. (Image credit: SEBASTIAN KAULITZKI/SCIENCE PHOTO LIBRARY via Getty Images)

"Most of the research has really focused on the gut microbiome," the community of bacteria and other microbes that live in the gut, said Dr. Christopher Lieu, a professor of medical oncology at the University of Colorado Anschutz and a medical adviser to the nonprofit Colorectal Cancer Alliance.

Microbiome disruptions may spur inflammation, which, in turn, may trigger DNA mutations that cause cancer. But these mechanisms are complicated, Lieu told Live Science, and there likely isn't one simple reason young people's microbiomes may be getting disturbed.

"It's going to be extraordinarily more complex than that," he said.

Aggressive disease in young people

What researchers are starting to learn is that colorectal cancer in people in their early 20s or younger tends to be a more aggressive disease than that often seen in older people.

"We do feel like it is a bit of a distinct disease than what we're seeing in older adults," said Dr. Erica Arnold, a pediatric surgery research fellow at Nationwide Children's Hospital in Columbus, Ohio. In October, Arnold presented new research on colorectal cancer in people ages 21 or younger at the annual meeting of the American Academy of Pediatrics.

Arnold and her colleagues analyzed the cases of 84 patients diagnosed between 2012 and 2023. They found that the median age of diagnosis was 16 years old and the median duration of symptoms before diagnosis was only 12 weeks long.

Only about 20% of the patients had a close relative with colorectal cancer, suggesting that for many of these young people, the disease did not necessarily emerge due to hereditary factors.

If you want my honest opinion, it does suggest that these cancers are developing differently.
Dr. Christopher Lieu, a professor of medical oncology at the University of Colorado Anschutz

Eighty percent of the study participants were diagnosed with Stage III or Stage IV disease, meaning the cancer had already spread locally and to lymph nodes or to other, distant organs when the patients were diagnosed. For comparison, in colorectal cancer patients of all ages, 60% are diagnosed in Stage III or IV, according to the Centers for Disease Control and Prevention (CDC).

In addition, Arnold said, one-third of the patients in their study had cellular markers of particularly aggressive cancer.

"Some of that might be related to delays in diagnosis," Lieu said, "but if you want my honest opinion, it does suggest that these cancers are developing differently."

The study's data was not nationally representative, but a recent analysis of CDC data has also found that colorectal cancer rates in youth are on the rise. In 1999, the diagnosis rate in kids ages 10 to 14 was 1 in a million. By 2020, it had risen to 6 in a million. For teens between 15 and 19, the rate of diagnosis went from 3 in a million to 13 in a million in that same time frame.

Unclear causes

There is no definitive reason for this rise, Lieu said. Research on the microbiome has suggested that processed food, antibiotic exposure in childhood, stress, reduced exercise and other lifestyle factors may contribute to this increased risk of colorectal cancer.

Some microbes may play a particularly strong role, at least in some cases of colorectal cancer. For instance, a specific variant of the common gut bacterium Escherichia coli is strongly associated with colorectal cancer; the variant carries a genetic segment and produces compounds that are toxic to genes. But this variant alone cannot explain all colorectal cancer cases in young people. Nor is it clear why the gut microbiome might be undergoing a shift in the first place.

"It may be a combination of food, antibiotic use and environmental exposures," Lieu suggested.

Regardless of the exact causes behind the cases, Arnold's new research pointed to the symptoms that deserve closer scrutiny in young people. Among the 84 patients in the study, 75% reported experiencing back and abdominal pain before their diagnosis, 45% had changes in their bowel movements, 43% experienced unexplained weight loss and 38% had rectal bleeding.

Exclusive to Live Science Pro

These are classic colorectal cancer symptoms, Arnold said, but they might be overlooked in this young age group because these same symptoms can have more common causes.

Parents should know that in most cases, stomach pain and gastrointestinal disruptions in kids are not caused by colorectal cancer, Lieu said, calling the cancer an "extraordinarily rare event." Nevertheless, pain or gastrointestinal upset that doesn't ease or that worsens over time needs a checkup, and symptoms like weight loss and blood in the stool are very unusual in kids and deserve extra attention.

"It's just important to investigate it to make sure we're catching colorectal cancer earlier rather than later in these patients," Arnold said.

This article is for informational purposes only and is not meant to offer medical advice.

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'> Colorectal cancer cases in kids have risen sixfold over past 2 decades ‪—‬ researchers are racing to understand why

The child was buried alongside two ceramic objects depicting defeated warriors about to be sacrificed. (Image credit: Huacas de Moche Archaeological Project - UNT)

Archaeologists in Peru have found an elaborate 1,500-year-old tomb that may hold the remains of a high-status toddler from a pre-Inca civilization.

The burial, which is from the Moche culture, also contained vessels depicting prisoners with rope around each of their necks and a sculpture of a human-bird deity.

Moche (also known as Mochica) culture developed along the northern coast of what is now Peru from the third to the ninth century. They created agricultural lands in the region's desert landscape, and their archaeological record includes monumental temples, water canals, pottery, metallurgy, textiles and a distinctive form of art. The Moche didn't have a written language, but they left behind thousands of realistic portrait vessels, which are somewhat similar to the prisoner sculptors found in the toddler's burial.

In the newfound tomb, the team unearthed a small skeleton, which is likely the remains of a toddler who was, at most, 2 years old, Carlos Rengifo-Chunga, director of the University of Trujillo's Huacas de Moche Archaeological Project, told Live Science. The child's sex is unknown.

A series of ceramic bowls and vases are half unearthed in a cave. — The child was buried alongside 32 ceramic objects associated with Moche culture. (Image credit: Huacas de Moche Archaeological Project - UNT)

Rengifo-Chunga and his colleagues also found two copper objects in the burial: a mask-like disk covering the child's face, and a half-moon object on their feet. In addition, the burial contained 32 ceramic objects associated with Moche culture, including those depicting the prisoners and the deity.

The tomb was large compared to the child's small size, and could have easily held an adult, Rengifo-Chunga said. It dates to the sixth or seventh century, he added.

The team unearthed the tomb inside the Uhle Platform at the Huacas de Moche archaeological site in northern Peru. The Uhle Platform is a mausoleum, attached to the Huaca de la Luna temple, with a patio archaeologists call the Patio of the Serpents. Of the more than 80 burials previously uncovered there, the tomb represents the only known child to receive this sort of lavish burial.

The elaborate funerary treatment, including the use of copper, and the location of the tomb all suggest that the child belonged to an elite class of Moche society, Rengifo-Chunga said.

The two prisoner sculptures are associated with the "ritual of combat," a common theme in Moche art. In this sort of imagery, two warriors fight each other, and the loser is stripped of his clothes and weapons, tied around the neck with a rope and offered as a human sacrifice, Rengifo-Chunga said. The prisoners depicted on these two vessels were the losing warriors, and their presence in the burial of a child is rare.

"One would normally presume that these kinds of vessels represent something related to the deceased's life," Rengifo-Chunga said. For example, a vessel like this might signify that the individual took part in combat.

Scenes showing an excavation inside a cave — Huacas de Moche Archaeological Project - UNT

But a toddler couldn't have taken part in such an activity. In general, archaeologists wouldn't expect to see elements of an adult ritual in the burial of a child. "This expands our knowledge on Moche funerary practices," he added.

The sculpture of the presumed deity depicts a human body with bird wings and a bird tail, although for some scholars it might be interpreted as a god in transformation, Rengifo-Chunga said. The deity holds a square shield in one hand and a goblet in the other, and is flanked by two bird "assistants" wearing ceremonial garments.

Inuit Figurine

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Can you put together last week's Astonishing Artifact?

'> Mold gold cape: A 3,900-year-old accessory that's one of the finest examples of prehistoric goldwork ever found Grace Liu, a doctoral student in machine learning at Carnegie Mellon University, told Live Science in an email. "If AI routinely removes that struggle, people may get the right answer in the moment but develop less robust independent capability."

Liu and her colleagues recruited 1,222 participants for the study, which was released as a preprint earlier this year and has now undergone peer review. The researchers designed three randomized controlled experiments, including two sets of mathematical fraction problems and a series of reading comprehension questions. The participants were split into three groups, so there was no overlap between the experiments. Each experiment took 13 to 15 minutes to complete.

In the first experiment, the team randomly assigned 354 participants to two groups: one that had access to an AI chatbot and one that didn't. The researchers gave both groups the same 12 fraction problems, which the AI group could get the answer to immediately or obtain clues about by prompting the chatbot. Then, the researchers removed the AI assistant without warning for a final set of three fractions, which all of the participants were given, regardless of their group.

Both groups had the option to skip problems. The researchers explicitly told the participants that there was no penalty for wrong answers, so skipping a problem was a deliberate decision to not engage with it, they wrote in the study. The participants in both groups were also given the correct answer to each problem if they got it wrong, so they could learn from their mistakes.

This first experiment showed that the participants in the AI group were more likely to solve fractions and less likely to give up when they had access to the chatbot compared with the other group. But when the AI was removed, their performance dropped and they skipped or failed more problems, suggesting that using AI impaired unassisted task performance, persistence and motivation.

The second experiment was a copy of the first experiment, but it had 667 participants and small tweaks in the trial design, including the addition of a pretest phase that helped the researchers eliminate participants who were unable to solve the most basic problems. The findings were similar to those of the first experiment, hinting that the use of AI for simple tasks harms perseverance and drive to complete those same tasks without AI, especially when AI is used to get direct solutions.

Liu acknowledged that calculators also allow people to offload computations, which could cause similar declines in independent performance. But "the reason we study AI specifically is that it allows people to offload reasoning across tasks across many domains," she said.

A person using a calculator to solve a math problem. — Calculators allow people to offload math problems, but their effects on reasoning aren't as far-reaching as the effects of AI. (Image credit: Kiyoshi Ota/Bloomberg via Getty Images)

In a third experiment, the team explored the impacts of AI assistance on reading comprehension, which draws on meaning-making skills and mental-model construction — the cognitive process of building internal representations of external reality. The trial included 201 participants, who were divided into a group with access to AI and a control group. The researchers gave both groups five comprehension questions before disabling the AI chatbot and handing each participant another three questions.

The results mirrored those of the first two experiments, suggesting that reduced persistence, in particular, was not an artifact of the math problems but a general outcome of cognitive offloading onto AI.

"The most significant finding is that people who offload more have higher declines in persistence (increased skip rate), which is an important skill that cuts across domains," Liu said.

One possible reason people stop trying once they have experienced help from AI is that they get used to the immediacy of answers and perceive any method that takes longer as inefficient, the researchers wrote in the study. But studies show that persistence through difficulty is essential for skill acquisition and learning, raising concerns about the long-term impacts of using AI for simple tasks.