Welcome to Altmetric’s “High Five” for October, a discussion of the top five scientific papers with the highest Altmetric scores this month. On a monthly basis, my High Five posts examine a selection of the most popular research outputs Altmetric has seen attention for that month.
Appropriate for the month of Halloween, this month’s top scientific papers often border on “outlandishly” curious findings!
Region that the Kepler Space Telescope can see.
Paper #1. Planet hunters find… Impact debris or an alien mega-structure?
Our top paper this month is titled “Planet Hunters X. KIC 8462852 – Where’s the Flux?” The paper, published in the Monthly Notices of the Royal Astronomical Society, is freely available via arxiv.org.
The paper uses insights gleaned by the Zooniverse citizen science network to investigate strange dips in flux, or light, from the star KIC 8462852. The star is invisible to the naked eye, but researchers have been observing it through the Kepler Space Telescope.
This paper presents the discovery of a mysterious dipping source, KIC 8462852, from the Planet Hunters project. In just the first quarter of Kepler data, Planet Hunter volunteers identified KIC 8462852’s light curve as a “bizarre”, “interesting”, “giant transit.” – Boyajian et al. 2015
The study attracted a great deal of attention from both traditional news and social media sources. And that is likely because one of the more outlandish (excuse the pun) scientific explanations for the sharp dips in flux observed coming from the star is that aliens have built a mega-structure around the star to harness its energy!
In a study first released online in September, a team of scientists has shown that KIC 8462852 has a mysterious flicker—for its age and type, the star should be much brighter than telescopes show it to be. While the research has not yet been reviewed for publication, it is already stirring up excitement in the scientific community and beyond; after eliminating other theories, some suggest that the only explanation for the flicker is the presence of light-blocking megastructures, built by aliens. – Akshat Rathi, qz.com
There are, of course, other less outlandish explanations for the flickering of this star. Science Friday has an informative and entertaining episode out on the study, which features study author Debra Fischer, a professor of astronomy at Yale University. Fischer describes two other explanations: a swarm of comets circling the star, or the debris of a recent planetary collision. Both of these explanations have their issues however, leading scientists to still consider the distant possibility of an alien mega-structure in follow-up research. Some of this follow-up research will most likely “point a massive radio dish at the unusual star, to see if it emits radio waves at frequencies associated with technological activity.”
Jason Wright, an astronomer from Penn State University, is set to publish an alternative interpretation of the light pattern. SETI researchers have long suggested that we might be able to detect distant extraterrestrial civilizations, by looking for enormous technological artifacts orbiting other stars. Wright and his co-authors say the unusual star’s light pattern is consistent with a “swarm of megastructures,” perhaps stellar-light collectors, technology designed to catch energy from the star. – Ross Andersen, The Atlantic
Only additional research and in-depth observation of this star will reveal the true cause the the strange flickering of KIC 8462852.
My money is on comet collisions. But part of me hopes I’m wrong. – Stuart Clark, The Guardian
But whatever is causing the flickering of KIC 8462852, Phil Plait writes on his blog Bad Astronomy, it’s big.
KIC 8462852 is a star somewhat more massive, hotter, and brighter than the Sun. It’s about 1,500 light-years away, a decent distance, so it’s too faint to see with the naked eye. The Kepler data for the star are pretty bizarre: There are dips in the light, but they aren’t periodic. They can be very deep; one dropped the amount of starlight by 15 percent, and another by a whopping 22 percent! Straight away, we know we’re not dealing with a planet here. Even a Jupiter-sized planet only blocks roughly 1 percent of this kind of star’s light, and that’s about as big as a planet gets. It can’t be due to a star, either; we’d see it if it were. And the lack of a regular, repeating signal belies both of these as well. Whatever is blocking the star is big, though, up to half the width of the star itself! – Phil Plait, Slate
Elephants on the move in Amboseli National Park, Kenya, East Africa. Image by Diana Robinson, Flickr.com
Paper #2. Long live the elephant, or how elephants crush cancer
Our second High Five paper was published in JAMA this month, titled “Potential Mechanisms for Cancer Resistance in Elephants and Comparative Cellular Response to DNA Damage in Humans.” The authors of this paper set out to identify why elephants have lower-than-expected rates of cancer given their size and life span.
The authors performed a survey of autopsy data collected by the San Diego Zoo across 36 mammalian species including African and Asian elephants. When they looked at cancer mortality and cancer-related genes in elephants, they found something remarkable. Elephants, despite their huge bodies and long life spans, have a cancer mortality rate of less than 5%. We humans, on the other hand, have between an 11% and 25% cancer mortality rate.
What is the elephant’s secret to cancer resistance? Elephants have 20 copies of the gene p53, a tumor suppressor famous for being involved in apoptosis or “assisted suicide” for cells with damaged DNA, for example.
The study authors were able to show that compared to humans, elephants have an increased apoptotic or “cell suicide” response following DNA damage that might otherwise lead to mutations and cancers.
The surprisingly low cancer rates in elephants and other hefty, long-lived animals such as whales—known as Peto’s paradox after one of the scientists who first described it—have nettled scientists since the mid-1970s. – Mitch Leslie, Science News
This paper was covered by over 35 news outlets and mentioned over 800 times on Twitter.
Nature has already figured out how to prevent cancer. It’s up to us to learn how different animals tackle the problem so we can adapt those strategies to prevent cancer in people. – Joshua Schiffman, quoted in NIH article
Several scientists and science writers, however, have pointed out that more research is needed to clarify exactly how elephants’ extra copies of p53 reduce these animals’ cancer risks.
The Road to Chernobyl. Image by Timm Suess, Flickr.com
Paper #3. Wildlife thriving in areas abandoned after the Chernobyl accident
Our next High Five paper is an open access paper published in Current Biology, “Long-term census data reveal abundant wildlife populations at Chernobyl.” The paper attracted the attention of news media and blogs in multiple languages.
According to NPR, “[w]hen you think of a nuclear meltdown, a lifeless wasteland likely comes to mind — a barren environment of strewn ashes and desolation.” But the area around Chernobyl appears to be teeming with wildlife today. Even if animals in the area are being affected by radiation in the area, the effects of this contamination are overshadowed by the fact that this area is now essentially a wildlife reserve relatively free of human disturbances.
It’s well-established that when you create large reserves and protect wildlife from everyday human activities, wildlife generally tend to thrive. – Jim Beasley, researcher at the Warnell School of Forestry at the University of Georgia, as quoted by NPR
The findings of this new study don’t necessarily imply that the area around Chernobyl is now safe for humans, or that the animals in the area are now safe for humans to hunt or eat. Radiation contamination in the area, and in the wildlife, persists. But it does appear that Chernobyl has become an unlikely wildlife haven, especially for larger animals normally under the pressures of hunting and habitat loss.
The researchers walked 35 routes totaling 315 kilometers, covering 14 routes all three years of the study and the remaining 21 routes in two out of three years. They spied tracks made by species including wild boar, elk, roe deer, red deer, wolf, fox, weasel, lynx, pine marten, raccoon dog, mink, ermine, stone marten, polecat, European hare, white hare, and red squirrel. […] Startlingly, the density of wolves is seven times higher near Chernobyl than elsewhere in the region. “We believe the high density of wolves within PSRER is due to a combination of abundant prey populations, greatly limited human activity, and lack of hunting pressure,” says Jim Beasley, a study co-author at the University of Georgia. – Conservation Magazine
Science News headlined, “Humans are worse than radiation for Chernobyl animals, study finds.” The authors of the Current Biology study reported no correlation between radiation contamination levels and animal track counts found in the region.
We’re not saying radiation is good for animals, but we’re saying human habitation is worse. – Jim Smith, environmental scientist at the University of Portsmouthin the United Kingdom, in press briefing
Ancestor Teeth. Image credit: Credit: S. Xing and X-J. Wu
Paper #4. Unexpected fossil teeth
Our forth High Five paper published in Nature in September 2015, “The earliest unequivocally modern humans in southern China,” reveals something unexpected about how early humans trekked around the globe. Based on the age of well-preserved fossil teeth found in the newly excavated Fuyan Cave in Daoxian (southern China), modern humans were in southern China 30,000–70,000 years earlier than in the Levant and Europe. This finding significantly changes our understanding of how early Homo Sapiens migrated out of Africa.
Listen to the Nature Podcast in which study author María Martinón-Torres explains how the ancient teeth challenge ideas of early human migration here.
The study authors dated the teeth to be around 80,000 to 120,000 years old.
Those ages buck the conventional wisdom that H. sapiens from Africa began colonizing the world only around 50,000–60,000 years ago, says Martinón-Torres. Older traces of modern humans have been seen outside Africa, such as the roughly 100,000-year-old remains from the Skhul and Qafzeh Caves in Israel. But many researchers had argued that those remains were only evidence of unsuccessful efforts at wider migration. – Ewen Callaway, Nature News
This is a rock-solid case for having early humans — definitely Homo sapiens — at an early date in eastern Asia. – Michael Petraglia, an archaeologist at the University of Oxford, as quoted in Nature News
The finding also begs the question, why did H. Sapiens only enter Europe around ~45,000 years ago according to known records, some 35-75,000 years after they were established in southern China according to the fossil teeth find? According to the Nature study authors:
Our results are relevant to exploring the reasons for the relatively late entry of H. sapiens into Europe. Some studies have investigated how the competition with H. sapiens may have caused Neanderthals’ extinction. Notably, although fully modern humans were already present in southern China at least as early as ~80,000 years ago, there is no evidence that they entered Europe before ~45,000 years ago. This could indicate that H. neanderthalensis was indeed an additional ecological barrier for modern humans, who could only enter Europe when the demise of Neanderthals had already started. – Liu et al. 2015
In other words, H. sapiens left Africa much earlier than we thought, but they may have had competition from Neanderthals in Europe.
Two of the study authors wrote about their findings for The Conversation: “Our fossil find suggests humans spread to Asia way before they got to Europe.”
Image: Jeremy Brooks, Flickr.com
Paper #5. Step away from that bacon
Our fifth and final High Five paper this month has been shocking, angering and entertaining (with photos of large piles of hotdogs and bacon) the internet this week. Not that the findings haven’t been a long time coming. This week, the World Health Organization (WHO) delivered a summary report published in The Lancet Oncology classifying high consumption of various processed red meats (such as hotdogs, smoked sausages, etc.) as a Group 1 carcinogen, along with smoking. The meat-cancer link is dose dependent however – it depends on how much processed red meat you eat.
After sifting through decades’ worth of scientific literature, an IARC working group of 22 experts from 10 countries classified the consumption of processed meat as a Group 1 carcinogen to humans (processed meats are defined as meats that have been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavour or improve preservation). This conclusion was reached on “sufficient evidence” that the consumption of processed meat causes bowel, or colorectal, cancer. – George Dvorsky, Gizmodo
Understanding the findings requires understanding the context of the risk. The increase in cancer risk for any single individual eating processed red meats is relatively small. However, the effect is significant if we consider the number of people who eat these products around the globe.
We know that, out of every 1000 people in the UK, about 61 will develop bowel cancer at some point in their lives. Those who eat the lowest amount of processed meat are likely to have a lower lifetime risk than the rest of the population (about 56 cases per 1000 low meat-eaters). If this is correct, the WCRF’s analysis suggests that, among 1000 people who eat the most processed meat, you’d expect 66 to develop bowel cancer at some point in their lives – 10 more than the group who eat the least processed meat. – Casey Dunlop, Cancer Research UK Blog
To be clear, this doesn’t mean that processed meat is as bad for you as smoking. (As Vox’s Brad Plumer explains, that’s not the case at all.) What it means is that according to the agency’s assessment, the links between processed meat and certain types of cancer are clear and well-established based on high-quality research. – Julia Belluz, Vox
You can read the summary report for yourself by registering with the publisher for free here. In the meantime don’t panic, but it might be worth reconsidering the balance of meats in your diet.