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An Ohio scientist claims to have found photographic proof of "insect and reptile-like" life on Mars. But, as always, it's not aliens, other researchers say.

William Romoser, a professor emeritus who specializes in arbovirology (the study of viruses transmitted by arthropods) and entomology at Ohio University, has compiled photographs from NASA Mars rovers that he says are evidence of life on Mars. "There has been and still is life on Mars," Romoser said in a statement.

But Romoser's evidence for this alleged Martian life comes only from his interpretation of these photographs. As he asserts in the findings he presented on Nov. 19 at the national meeting of the Entomological Society of America, the images show the shapes of life-forms that look similar to reptiles and bee-like insects. According to the statement, these observations are of both fossilized and living creatures on the surface of Mars.
Insects on Mars? Professor Suggests It After Studying Rover Pics 5 Bold Claims of Alien Life

(Image credit: William Romoser)

"There is apparent diversity among the Martian insect-like fauna which display many features similar to Terran insects that are interpreted as advanced groups - for example, the presence of wings, wing flexion, agile gliding/flight, and variously structured leg elements," Romoser said about the supposed life-forms.

(Image credit: Analysis by William Romoser)

Seeing things on Mars
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Now, if you really squint at these images and have already read that someone else thinks that they look like insects and reptiles, you might think they look like insects and reptiles, too. But, according to David Maddison, a professor in the integrative biology department at Oregon State University, this "proof" is likely just an example of pareidolia, a phenomenon in which people see patterns in random data.

"I, personally, have pareidolia with respect to insects, beetles in particular," Maddison told Space.com in an email. "I've worked on beetles for decades; I have collected many thousands of beetles around the world. Through the years I have built into my brain a pattern-recognition system for picking out beetles."
Related:

(Image credit: William Romoser)

Mars Illusions: The 'Face on Mars' and Other Optic Tricks
"However," Maddison added, "there is a rate of false positives - my 'seeing' beetles where there are none, which I realize when I investigate further. The false positives are usually fairly low toward the end of a field trip, as I retrain my brain, but in some circumstances - i.e., a lack of beetles in the environment - that rate of false positives is higher, as my eyes don't naturally get drawn to the real beetles, instead latching on to whatever beetle-like blob is out in the landscape.

"I do not think there are insects on Mars. The photographs that are in that press release you sent are entirely unconvincing, as they fall within the range expected in zillions of non-insect objects photographed in lowish resolution on a Marscape," Maddison said. "It is vastly more parsimonious to presume the blobs are simply rocks. As has been said, 'extraordinary claims require extraordinary evidence'; those pictures are far, far less than extraordinary."

And simply pointing out suggestive shapes in NASA photos may not be the best way to draw conclusions in the search for life beyond Earth.
Related: Discovering Extraterrestrial Life Would Be Slow and Uncertain
"I think it's really easy to find patterns in images, especially when they're out of context," Nina Lanza, a planetary scientist at Los Alamos National Laboratory, told Space.com. "They're little clips of larger images and there's no scale bar on them ... you could imagine a lot of different shapes in there. That's not a good way to do this kind of assessment."

Putting things in perspective

Researchers continue to extensively study the Martian landscape, soil, history and atmosphere. And, while scientists actively search for signs of life, compiling data that might one day serve as evidence for past or present life on Mars or beyond, there exists no concrete proof of any life-forms on Mars (or elsewhere beyond Earth).

"That's just the way it is. We haven't yet been able to make that statement, but we are looking," Lanza said. "We are just as excited, we want to do this too! We are going to tell you as soon as we find life."

Regarding Romoser's work and assertion that there is proof of life on Mars, NASA officials responded to Space.com with the following statement:

"The collective general opinion of the large majority of the scientific community is that current conditions on the surface of Mars are not suitable for liquid water or complex life. As part of its astrobiology objectives, one of NASA's key goals is the search for life in the universe and the Mars 2020 rover, launching next summer, is our next stage in exploring the potential of past life on the Red Planet.

"Although we have yet to find signs of extraterrestrial life, NASA is exploring the solar system and beyond to help us answer fundamental questions, including whether we are alone in the universe. From studying water on Mars, probing promising "oceans worlds," such as Enceladus, Europa, and Titan to looking for biosignatures in the atmospheres of planets outside our solar system, NASA's science missions are working together with a goal to find unmistakable signs of life beyond Earth."

The harm that dubious claims can cause

To scientists like Lanza and Maddison, the fact that this claim is not truly "proof" of life on Mars is obvious. But to the untrained eye, to the person who might only have time to skim the headline on his or her commute home, overblown claims like this can be damaging.

"When we have this kind of sensationalist headline, it's really hard for the public to know whether or not this is true," Lanza said. "It seems legitimate, it's coming from Ohio University, these are real institutions and so ... when we actually find something on Mars and beyond, if we do that, it will be less of an impact ... people keep hearing 'we've already found life on Mars.'"

"It takes away the excitement from our real discoveries," she added.

Editor's Note: Following the publication of Romoser's work, the press release for the study was taken down.

"I wanted to let you know that the faculty member no longer wishes to engage with media regarding this research, so we have opted to remove the story from our website and EurekAlert," Jim Sabin, theMedia Relations Manager at Ohio University, told Space.com in an email.

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It's Still Not Aliens: 'Mars Bug' Claim Could Damage the Search for Life

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An Ohio scientist claims to have found photographic proof of "insect and reptile-like" life on Mars. But, as always, it's not aliens, other researchers say. William Romoser, a professor emeritus who specializes in arbovirology (the study of viruses transmitted by arthropods) and entomology at Ohio University, has compiled photographs from NASA Mars rovers that he says are evidence of life on Mars.

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Un científico asegura que encontró insectos en Marte a través de fotos tomadas por Curiosity

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El doctor Romoser afirmó que sus hallazgos son justificación suficiente para realizar estudios a profundidad y plantear nuevas preguntas en torno al planeta rojo

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INTRODUCTION

It has long been known that a wide array of microbes colonize the human body and that the interaction between these organisms and their host may be critical in health and disease. However it is only recently, with the advent of new molecular techniques, that the full diversity of this "microbiome" has been appreciated. The human intestinal microbiome is among the most complex of the body sites: it includes 500-1000 species and several million genes. New research shows that there is a complicated bi-directional relationship between the intestinal microbiome and the host which is likely critical for human health as well as implicated in disease pathogenesis. The gut microbiome appears to be important in digestion of food and extraction of nutrients, in modifying the host immune response, in protecting against infection, in the metabolism of drugs, and in participation in and regulation of host metabolism. At the same time the microbiome is itself modifiable by diet, host and environmental factors. In this review we seek to outline the current state of knowledge on what characterizes a "healthy" or "normal" intestinal microbiome, what factors modify the intestinal microbiome in the healthy state and how the intestinal microbiome affects normal host physiology. We also provide a snapshot of disease implication.

WHAT CHARACTERIZES A "HEALTHY" OR "NORMAL" INTESTINAL MICROBIOME?

The majority of research on the intestinal microbiome, including the pioneering work done by the Human Microbiome Project to characterize the microbiome in healthy individuals has focused on the large intestine (colon) and feces, and the diverse microflora of this distal gut region as characterized by stool studies will be the focus of our review as well. [ 1] However, the gastrointestinal system is certainly not limited to the distal gut, and it is important to note that the bacterial composition of the esophagus, stomach and small intestine appears to be significantly different from that of the colon both in diversity and in which microbes predominate. In the esophagus, for example, limited diversity and the presence of a few genera, such as streptococcus, appear to be associated with health, while the low pH of the gastric lumen creates an environment that selects for a limited number of acid-tolerant bacterial populations. [ 2*] In addition, in the colon, there appear to be differences between the microbial populations found in the lumen (stool) and those found in mucosal tissue samples.[ 3]

The healthy human distal gut microbiota is very diverse, likely encompassing over 1000 species. There may be a certain shared "core microbiome," which in healthy individuals appears to be dominated by the phyla Firmicutes and Bacteriodetes, followed by Actinobacteria and Verrucomicrobia. [ 2*] However, the relative proportions and species present within individual microbial communities may vary dramatically. Further studies characterizing microbial gene profiles suggest that there are shared common functional pathways across individuals (a "functional core microbiome") but these pathways may be fulfilled by different types or communities of bacteria in different people.[ 4]

The gut microbiota has been further described by Arumugam et al to form three distinct enterotypes dominated by a relatively high representation of Bacteroides, Prevotella or Ruminococcus. [ 5] This characterization has been somewhat controversial, with some finding that patients' microbiota cluster into only two Prevotella or Bacteroides dominated "enterotypes." [ 6] Others have proposed that rather than fitting into discrete "enterotypes," individual patient's intestinal microbiota relative to others can be conceptualized as existing along "enterogradients," i.e. along a continuum of microbial community structures. [ 7]

Attempts to describe what features represent a "healthy" or "good" microbiome have characterized the intestinal microflora in terms of certain core genera which appear to be associated with health, microbial diversity, the relative abundance of certain microbes, microbial gene richness, and/or resilience of microbial populations. Greater diversity of the intestinal microbiota appeared to be associated with better health (and better diet) in an elderly cohort, while decreased diversity was observed, for example, in patients with recurrent Clostridium difficile infection. [ 8, 9] Another study suggested that greater bacterial richness may also be beneficial, as individuals categorized as having a low stool bacterial gene count (<480,000 genes) had more overall adiposity, insulin resistance, and dyslipidemia as well as a more pronounced inflammatory phenotype as compared with high gene count individuals. Furthermore the relative proportions of certain kinds of bacteria or the metabolic profile generated by certain microbial communities may be important to health. [ 10, 11] In the absence of marked diet changes, studies show that a normal individual's gut microbiota may be quite stable over the long term. [ 12] Given this, a key feature of a healthy microbiome may be both its ability to resist change in the setting of stress (resistance) as well as its ability to return to an equilibrium state following stress (resilience) [ 7]. A recent study found that human gut microbes from all dominant phyla are resistant to high levels of inflammation-associated antimicrobial peptides. In Bacteroidetes, one mechanism for this resistance appeared to be related to lipopolysaccharide (LPS) modification. Bacteroides thetaiotaomicron mutants which lacked this mechanism were displaced from the microbiome of mice during inflammation triggered by Citrobacter rodentium infection. This may represent at least one mechanism which helps to determine the stability of important members of the healthy microbiota during perturbation. [ 13**]

WHAT FACTORS MODIFY THE INTESTINAL MICROBIOME IN THE NORMAL STATE?

Age, the host immune system, host genetics, diet and antibiotic use all appear to modify the intestinal microbiome.

Age

The microbiome evolves quickly in early life, and is initially characterized by relatively low diversity and instability. Most colonization of the infant gut begins at delivery, although bacteria can be found in meconium. Infants born vaginally are initially colonized with vaginal microbiota, such as Lactobacillus and Prevotella, whereas those born by caesarian section are initially colonized by skin microbes. In the first year of life, breastfed infants have an increased proportion of Bifidobacteria and a decreased proportion of anaerobic organisms relative to formula fed infants. Some Bifidobacteria have specialized enzymes that allow them to metabolize human milk oligosaccharides, furthermore they have been linked to a variety of potentially beneficial effects such as increasing the production of immunoglobulin A and fortifying the gut mucosal barrier. The infant microbiome interestingly appears to be enriched in certain genes that facilitate the acquisition of nutrients-for example those that encode the de novo synthesis of folate. Adults in contrast possess a greater number of genes for dietary folate use. The microbiome shifts again with the introduction of solid foods and, by around age 3, children have a relatively stable, adult-like intestinal microbiome. [ 2*, 14*]

If the infant microbiome is significantly different from that of the healthy adult, so too there have been some changes, albeit more subtle, observed with advancing age. It appears that with age, the proportions of many members of the Firmicutes family, bifidobacteria and Faecalibacterium prausnitzii decrease, whereas proportions of E. coli, other Proteobacteria and staphylococci increase. It has also been suggested that elderly individuals have more variation in the evenness (or relative proportion of different bacterial species) in their microbiota, and further that their microbiomes may tend to represent a proinflammatory phenotype, based on decreased potential for B12 synthesis, increased potential for DNA damage, stress response and immune system compromise. [ 2*, 15]

The Host Immune System

In the gut, a very dense community of microbes is in constant close proximity to the epithelial cell surface, a situation which has the potential to lead to significant immune stimulation and deleterious inflammation. However, the healthy intestinal immune system has multiple mechanisms of tolerance that prevent excessive inflammation. First, there are two mucus layers in the colon. The first is a loosely adherent layer that is colonized by bacteria, but the second is a dense, strongly adherent mucus layer which is devoid of bacteria. This dense inner mucus layer covers the epithelial surface and provides a physical barrier that prevents direct contact between the microbes and the immune system. [ 16] Secondly, in the small intestine, antimicrobial peptides secreted by the host help to maintain distance of bacteria from the epithelium. Finally, T cell responses to microbes in the intestine are suppressed, further helping to prevent inappropriate inflammation. The healthy immune system serves to modify the microbiome. Insights into its actions come principally from mouse studies in which mice with certain immune deficiencies (such as mutations in IgA or the function of innate lymphoid cells) appear to lead to alterations in the composition of gut microbiota, and the accumulation of potentially pathogenic organisms such has Klebsiella, Proteus and Helicobacter. [ 17*]

Host genetics

Family members have been observed to have more similar microbiota than unrelated individuals, raising the possibility that genetics may shape the microbiome. A recent study examining fecal samples from 977 individuals including from both monozygotic and dizygotic twin pairs showed that microbiomes were more similar for twins than for unrelated individuals and more similar for monozygotic than dizygotic twins. They also found that the family Christensenellaceae appeared to be the most highly heritable taxon and was associated with low body mass index. [ 18*]

Diet

One of most important modifiers of the intestinal microbiome appears to be diet, both shaping its composition and functional metabolism. [ 14*] De Filippo et al showed that the intestinal microbiota of children living in rural Burkina Faso differed significantly from children living in Florence, Italy. The microbiota of the children in Burkina Faso, who ate a high fiber diet rich in carbohydrates and non-animal protein, had greater microbial richness, greater abundance of Prevotella with lower abundance of Bacteroides, and seemed to produce more short chain fatty acids - likely reflective of an enhanced ability to break down fiber, starch, oligosaccharides and carbohydrates from a diet of whole grains that escape digestion in the small intestine. The European children in contrast ate a diet high in sugar, starch, animal protein, fat and low in fiber. [ 19] Another study comparing the fecal microbiota of children in Bangladesh versus the United States showed similar results. [ 20] Wu et al showed in a study in the US that long term consumption of a diet high in protein and animal fat was associated with a predominance of Bacteroides, whereas a low fat, high carbohydrate diet was associated with a microbiota dominated by Prevotella. [ 6]

Wu et al also conducted a controlled feeding experiment in which 10 individuals who were originally in the Bacteroides "enterotype" were fed either a high fat/low fiber or a low fat/high fiber diet. Interestingly, there were changes seen in the microbiota within 24 hours, but these were relatively modest and did not result in the patients switching from one enterotype to another. [ 6] In a study by David et al, 10 individuals were fed either an almost entirely animal-based diet or an entirely plant-based diet. Within 24 hours, a relative increase in several types of bacteria resistant to bile acids was noted with consumption of the animal-based diet. The animal-based diet was also associated with increased expression of key genes for vitamin biosynthesis, the degradation of polycyclic aromatic hydrocarbons (carcinogenic compounds produced during the charring of meat) and the increased expression of β-lactamase genes. This diet decreased the levels of Firmicutes that metabolize dietary plant polysaccharides. Foodborne microbes from both diets including bacteria, fungi and viruses were noted to transiently colonize the gut. Interestingly, the microbial structures of each individual microbiome returned to baseline within 3 days of stopping the diet. [ 21**]

An intriguing paper by Suez et al using data both from mice and limited data from humans suggested that consuming non-caloric artificial sweeteners led to an increase in glucose intolerance, possibly mediated by changes to the intestinal microbiota. Mice (and humans) fed large amounts of non-caloric sweeteners had a microbiome enriched in Bacteroides, and enriched in glycan degradation pathways previously linked to enhanced energy harvest in obese patients. Furthermore, differences in glucose intolerance between non-caloric sweetener drinking mice and controls were abolished after antibiotic treatment. [ 22*]

Finally, studies in populations in Japan suggest that genes encoding enzymes that metabolize marine red algae have been transferred from marine bacteria to specific bacteria in the human intestine, and that these bacteria and the genes they contain have then been widely disseminated in the population. [ 23]

Antibiotics

While antibiotics may not necessarily be considered part of the "normal" human state, the ubiquitous nature of their use means that many (perhaps most) healthy adults will have taken at least one course in their lifetimes. Antibiotics have a significant short term impact on the gut microbiota, with decreases in richness and diversity seen within 3-4 days after antibiotic administration. Changes in community membership and composition are also seen. [ 24] The extent of these changes, particularly on individual community members, differs by type of antibiotic administered. However, the impact of even short courses of antibiotics may have long term effects on the intestinal microbiota. In one study, after short term clindamycin administration, Bacteroides species composition was still significantly altered 18 months later. [ 25] In another study 3 patients were given two 5 day courses of ciprofloxacin, 6 months apart. After the first administration, in 2 subjects the intestinal microbiota largely returned to the pre-antibiotic state. However, after two doses of ciprofloxacin, all three patients had intestinal microbiota that was altered from the pre-antibiotic state, and these alterations persisted 2 months after the last dose of antibiotics. [ 24] Finally, patients with recurrent Clostridium difficile, which is an antibiotic-associated infection, have been shown to have intestinal microbiota characterized by decreased diversity.[ 9]

HOW DOES THE MICROBIOME AFFECT NORMAL HOST PHYSIOLOGY?

The microbiome appears to significantly impact both the immune system and host metabolism.

Immune system

The impact of the microbiome on the host immune system is an active area of research. Data principally from animal models implies that the microbiome has important effects on the structural development and function of gut-associated lymphoid tissues, T cells and B cells, although the details of these interactions remain under study. Interestingly, studies comparing germ free mice to conventionally housed mice show that the germ free mice seem to have impaired development of gut associated lymphoid tissues, such as Peyer's patches and isolated lymphoid follicles. Early stages of B cell development occur in the intestinal mucosa (as well as in the fetal liver and bone marrow), and it appears that editing of receptors on developing intestinal B cells are regulated by extracellular signals induced by gut microbiota. Further, IgA-producing B cells mature in Peyer's patches under stimulation from commensal organisms. Similarly, germ free mice appear to have decreased numbers of T helper Th1 and Th17 cells. GF mice also have reduced numbers of T regulatory (Foxp3+) cells in the colonic lamina propria; this reduction can be reversed by colonizing the mice with intestinal microbiota. Additionally, specific types of Clostridia and possibly Bacteroides seem to have the ability to induce T regulatory cells. Induction of T regulatory cells by the microbiota appears to protect mice form colitis, infection with enteric pathogens and allergic diarrhea, suggesting that this interaction is important in gut homeostasis in the healthy individual. Whether innate lymphoid cells are affected by gut microbiota is, as yet, controversial, though some studies suggest that microbiota may be important for the differentiation of group 3 innate lymphoid cells and may play a role in their regulation as well. Finally, the secretion of both pro and anti-inflammatory cytokines by macrophages, dendritic cells and neutrophils appears to be regulated, at least in part, by intestinal flora. [ 17*]

The observation that there are decreased responses to certain oral vaccinations in children living in a number of developing countries as compared with children living in Westernized countries further suggests that the intestinal microbiota may have important effects on the immune system, though these interactions are complex and likely affected by a number of factors, including malnutrition. For example, oral rotavirus vaccine elicits immune responses in only 49% of children living in Malawi as opposed to over 95% of children living in Westernized countries. Populations with greater enteric disease burden experience lower efficacy of the cholera vaccine, and studies in children from Chile show that those with small bowel bacterial overgrowth respond less well to the oral cholera vaccine. [ 26] A recent study looking at IgG response to influenza vaccine in mice showed that both germ free and antibiotic-treated mice had decreased short term IgG responses to trivalent inactivated influenza vaccine as compared with conventionally housed mice. If germ free mice were conventionalized by transfer to standard housing conditions, influenza-specific IgG concentrations recovered to levels comparable to the control mice. The mechanism of this observed effect was hypothesized to be related to sensing of the microbiota by toll like receptor 5, a cell-surface receptor specific for flagellin. Interestingly, the same reduction in immune response in germ free and antibiotic-treated mice was not seen with live attenuated vaccines (such as the yellow fever vaccine). [ 27*]

Further evidence of the critical role that the intestinal microbiota play in immunity comes from the oncology literature where, in mouse models, it has been shown that antibiotic-treated or germ free mice have a poorer response to chemotherapy drugs. Cyclophosphamide, for example, works in part by stimulating antitumor immune responses. Viaud et al found that cyclophosphamide alters the composition of the gut microbiome and induces translocation of some gram positive bacteria into lymphoid organs, where the bacteria then stimulate a certain subset of 'pathogenic' T helper 17 cells and memory T helper 1 immune responses. Germ free or antibiotic-treated mice exhibited a reduced T helper 17 response, and their tumors were resistant to cyclophosphamide. [ 28]

Metabolism

The intestinal microbiota both dramatically expand the host's range of metabolic capabilities and help to regulate host metabolism in a range of ways that we are only beginning to understand. [ 29*] Colonic microorganisms play an important role in the synthesis of micronutrients such as vitamin K, B12, biotin, folic acid and pantothenate, as well as absorption of calcium, magnesium and iron. [ 30] Microbiota in the colon encode a vast array of carbohydrate active enzymes which allow them to break down indigestible dietary residues, releasing short chain fatty acids which are important for health and immunity. Butyrate, for example, appears to be important in the differentiation of T regulatory cells. [ 2*] Patients with inflammatory bowel disease have fewer butyrate-producing bacteria in their intestine, which may be an important factor driving intestinal inflammation. [ 29] Colonic organisms also break down proteins into amino acids, which can then be converted, also by intestinal bacteria, into a variety of signaling molecules and antimicrobial peptides that promote both resilience and resistance to infection. [ 2*]

The importance of the gut microbiota to metabolism may extend beyond regularly consumed dietary compounds to drug metabolism. One of the best known examples of this is digoxin. For decades, it has been clear that in a subset of individuals digoxin is inactivated and the inactive metabolite secreted. Broad spectrum antimicrobial therapy was shown to block digoxin inactivation and simultaneously resulted in increased serum levels of the drug. Finally, it was discovered that Eggerthella lenta was the gut bacteria capable of catalyzing the inactivation of digoxin. In mouse models, inactivation of digoxin was blocked by increasing protein intake, (likely an inhibitory effect of arginine). [ 29*]

It appears that the microbiome is critical in regulating host metabolism and may be an important factor in preventing (or promoting) obesity and insulin resistance. As mentioned above, there are notable differences in the microbiota of obese versus lean individuals. Some studies have found differing ratios of Firmicutes to Bacteroidetes [ 10], while others have noted differences in bacterial richness and diversity. Other studies have noted that the gut microbiota of obese individuals have an increased capacity for energy harvest. [ 31*, 32] In mice, transfer of fecal material from obese and lean littermates also appeared to transfer each phenotype: recipients of feces from obese donors gained 15-17% more adiposity that those from lean donors. [ 33*] Feces transferred to mice from obese and lean human twins also demonstrated a similar transfer of phenotype. Moreover, when the mice were fed a 'good diet' (low fat, high fruit and vegetable), the lean flora appeared dominant; i.e. when mice who had received feces from an obese human were cohoused with mice who received feces from a lean human, both exhibited a lean phenotype. [ 34] Intriguingly, a recent small study in which intestinal microbiota were transferred from lean donors to patients with metabolic syndrome led to increased insulin sensitivity in the recipients. [ 35]

A SNAPSHOT OF THE DISEASE IMPLICATIONS OF THE MICROBIOTA

As summarized in this piece, recent work has set the framework for understanding if and how the microbiota contributes to disease pathogenesis. This critical area holds promise for insights into new disease diagnostics and therapeutics. Because of its luminal association with the most dense microbiota on the human body, colon diseases are a particular target of initial investigations into the microbiota contributions to disease. Our foray into this area grew from a recognition that the toxin secreted by a bacterium associated with diarrheal disease, enterotoxigenic Bacteroides fragilis, activated carcinogenic mechanisms in colonic epithelial cells. [ 36*] Remarkably, upon the addition of this single bacterium to the complex colon microbiota in a susceptible mouse model, marked induction of distal colon adenomas was observed [ 36*]. Initial translation of these laboratory findings to the bedside revealed that nearly all patients with colon cancer are colonized with enterotoxigenic Bacteroides fragilis and, in many cases, with more than one strain of enterotoxigenic Bacteroides fragilis whereas individuals undergoing screening colonoscopy are significantly less frequently colonized. [ 37*] Nonetheless, ~50% of those undergoing screening colonoscopy were colonized with enterotoxigenic Bacteroides fragilis suggesting that exposure to enterotoxigenic Bacteroides fragilis is common. Importantly, additional studies suggest that right colon cancer displays a striking difference in microbiota organization compared to left colon cancer. Namely, the mucosa of right colon tumors (cancers and adenomas) as well as their normal tissues distant from the tumors are covered in a mucosally adherent polymicrobial and invasive biofilm that is further associated with activation of pro-carcinogenic colon tissue mechanisms. In this work, microbiome sequencing did not reveal these differential findings between right and left colon making it clear that to understand the contribution of the microbiome to disease requires use of diverse approaches (e.g., microbiologic, biologic and genomic). [ 38*]

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It has long been known that a wide array of microbes colonize the human body and that the interaction between these organisms and their host may be critical in health and disease. However it is only recently, with the advent of new molecular techniques, that the full diversity of this "microbiome" has been appreciated.

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Hace unos 5.300 años, en la región de los Alpes que ahora ocupan Italia y Austria, murió un hombre de algo más de cuarenta años. El análisis de sus restos, encontrados bajo el hielo por dos alpinistas en 1991, sugiere que no tuvo una muerte plácida. En el hombro se halló una flecha de piedra, tenía un corte profundo en la mano y había recibido un fuerte golpe en el cráneo. Antes del probable enfrentamiento que acabó por matarlo ya lo estaba pasando mal. Los análisis de aquel hombre de hielo, bautizado como Ötzi, mostraban que tenía artritis y le dolerían las rodillas mientras ascendía hasta los más de 3.000 metros de altitud donde fue encontrado. El análisis de su genoma indicaba que sufría la enfermedad de Lyme, una infección bacteriana transmitida por garrapatas, y en su estómago se encontraron plantas medicinales empleadas para tratar dolor de estómago.

Ahora, un análisis de los microbios de su intestino muestra que, efectivamente, algo andaba mal. En un artículo que se publica hoy en la revista Science, un equipo de científicos liderado por Albert Zink, director del Instituto de Momias y del Hombre de Hielo de Bolzano (Italia), ha detectado una cepa de la bacteria Helicobacter pylori y moléculas que indican que ya podía estar fastidiando a Ötzi. No obstante, no se puede "decir cómo de severa era la infección", explica Frank Maixner, coordinador del instituto y primer autor del trabajo.

Dos investigadores toman muestras del cuerpo de Ötzi EURAC/Marion Lafogler

Este microorganismo, culpable de úlceras y gastritis, lleva acompañando a los humanos durante al menos 100.000 años. Esa circunstancia convierte al patógeno en un buen aliado para conocer los movimientos migratorios humanos a través de las diferentes versiones de la bacteria desarrolladas en las distintas poblaciones humanas. El equipo que hoy publica sus resultados en Science descubrió que la cepa que sufría el desdichado hombre de hielo, además de un alto grado de cercanía a las cepas de los europeos modernos, era muy próxima a las cepas prehistóricas encontradas en la región de la India. Sin embargo, a diferencia de los humanos actuales de la región, solo contenía una leve presencia de cepas del Norte de África.

La información sugiere según Zink y sus colegas que las versiones norteafricanas de H. pylori llegaron a los estómagos de los europeos en migraciones recientes, posteriores a la época en que vivió y murió el hombre de los hielos.

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Ötzi, el hombre de los hielos, tenía problemas de estómago

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Hace unos 5.300 años, en la región de los Alpes que ahora ocupan Italia y Austria, murió un hombre de algo más de cuarenta años. El análisis de sus restos, encontrados bajo el hielo por dos alpinistas en 1991, sugiere que no tuvo una muerte plácida.

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The NCA Guide to Brewing Essentials

Coffee is personal - the right way to make it is how you like it best.

That being said, mastering a few fundamentals will help you perfect your technique. From here, we encourage you to experiment with different roasts, origins, or preparation methods.

Here are our tips to brew a classic cup of coffee.

The Equipment

Make sure that your tools - from bean grinders and filters to coffee makers- are thoroughly cleaned after each use.

Rinse with clear, hot water (or wipe down thoroughly), and dry with an absorbent towel. It's important to check that no grounds have been left to collect and that there's no build-up of coffee oil ( caffeol), which can make future cups of coffee taste bitter and rancid.

If you're using a single-serve coffee maker, check our guide for keeping your machine in top shape.

The Beans

Great coffee starts with great beans. The quality and flavor of your coffee is not only determined by your favorite brewing process, but also by the type of coffee you select. There can be a world of difference between roasts, so check out our roasting types guide.

Some of the flavor factors include:

While there are a lot of choices, remember that there's no right or wrong - for instance, you can choose a dark, flavorful espresso roast coffee and still have it ground to be brewed in a drip system. Have fun trying and enjoying different combinations.

Freshness

Purchase coffee as soon as possible after it's roasted. Fresh-roasted coffee is essential to a quality cup, so buy your coffee in small amounts (ideally every one to two weeks). Check out our helpful tips on how to store coffee to keep it as fresh and flavorful as possible.

And please, never reuse your coffee grounds to make coffee. Once brewed, the desirable coffee flavors have been extracted and only the bitter ones are left. Instead, check out these six ways to recycle your old grounds.

The Grind

If you buy whole bean coffee, always grind your beans as close to the brew time as possible for maximum freshness. A burr or mill grinder is best because the coffee is ground to a consistent size.

A blade grinder is less preferable because some coffee will be ground more finely than the rest. If you normally grind your coffee at home with a blade grinder, try having it ground at the store with a burr grinder - you'll be surprised at the difference! (Whichever option you use, always follow manufacturers' recommendations when using your grinder, and be mindful of any necessary safety considerations.)

The size of the grind is hugely important to the taste of your coffee. If your coffee tastes bitter, it may be over-extracted, or ground too fine. On the other hand, if your coffee tastes flat, it may be under-extracted, meaning your grind is too coarse.

(Check out this simple infographic to help you determine the the best texture for your preferred brewing method.)

If you're having the coffee ground to order, tell the professionals where you purchase your coffee exactly how you will be brewing it. Will you be using a French Press? A flat or cone drip filter? A gold mesh filter? They will grind it specifically for your preparation method.

The Water

The water you use is very important to the quality of your coffee. Use filtered or bottled water if your tap water is not good or has a strong odor or taste, such as chlorine.

If you're using tap water, let it run a few seconds before filling your coffee pot, and be sure to use cold water. Avoid distilled or softened water.

Coffee-to-Water Ratio

A general guideline is called the "Golden Ratio" - one to two tablespoons of ground coffee for every six ounces of water. This can be adjusted to suit individual taste preferences.

Check the cup lines or indicators on your specific brewer to see how they actually measure. And remember that some water is lost to evaporation in certain brewing methods.

Water Temperature

Safety first! Of course, any time you are working with heat and hot beverages, take all necessary precautions for everyone from those preparing coffee, to those being served, and drinking coffee.

Your brewer should maintain a water temperature between 195 to 205 degrees Fahrenheit for optimal extraction. Colder water will result in flat, under-extracted coffee, while water that is too hot will also cause a loss of quality in the taste of the coffee. (However, cold brew does not need any heat.)

If you are brewing the coffee manually, let the water come to a full boil, but do not over boil. Turn off the heat source and allow the water to rest a minute before pouring it over the grounds.

Coffee usually cools rapidly after being served, depending upon the container from which it is being served. And, many coffee drinkers may add cream or milk which also has a cooling effect. Ultimately, the temperature at which any individual coffee drinker will prefer their coffee is a personal preference, like so many other things that make coffee special. These are some of the reasons why it is best to serve coffee right after brewing, when it is fresh and hot - typically at a temperature of 180-185F, according to research.

Of course, with respect to drinking coffee, vs. serving, you should always allow your coffee - or any hot beverage - to reach a comfortable temperature before drinking. One study has shown that coffee drinkers typically drink their coffee at 140 degrees Fahrenheit or below.

And again, those preparing and serving coffee need to be mindful of safety, which could include factors such as the location where coffee is being served, and the coffee drinkers themselves, which can only be assessed by those preparing and serving coffee.

Brewing Time

The amount of time that the water is in contact with the coffee grounds is another important flavor factor.

In a drip system, the contact time should be approximately 5 minutes. If you are making your coffee using a French Press, the contact time should be 2-4 minutes. Espresso has an especially brief brew time - the coffee is in contact with the water for only 20-30 seconds. Cold brew, on the other hand, should steep overnight (about 12 hours).

If you're not happy with the taste of the final product, you're likely either:

Over-extracting - the brew time is too long

Under-extracting - the brew time is too short

Experiment with the contact time until you get the right balance for your taste.

Enjoy your coffee!

Prepared coffee begins to lose its optimal taste moments after brewing, so only make as much coffee as you'll drink. Otherwise, coffee can be poured into a warmed, insulated thermos to be consumed within an hour.

(Don't worry - old coffee probably isn't dangerous, just not very appealing. Always use your best judgement before ingesting anything, no matter what you read on the Internet.)

Try to enjoy your coffee as thoughtfully as it was prepared - take in the aroma, and notice the flavors in each sip. Many people have been instrumental in bringing it to your cup.

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The NCA Guide to Brewing Essentials Coffee is personal - the right way to make it is how you like it best. That being said, mastering a few fundamentals will help you perfect your technique. From here, we encourage you to experiment with different roasts, origins, or preparation methods.

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Vikings made their bloody but brief mark on history hundreds of years ago through their nomadic lifestyle and wild practices of raping, pillaging and conquering anything or anyone who crossed their path. These nomads were often seen as savages as they traveled throughout Europe, but the Vikings held a high regard for the life (and death) of their fellow Norsemen.

So how did they honor their dead? Nailing down the exact rituals of Viking funerals is difficult, as they kept few written accounts of their lives and deaths, but thanks to a few remaining accounts, and archaeological remains that have been found throughout much of Europe, it's possible to resurrect some of their funeral traditions.

Most Vikings were sent to the afterlife in one of two ways-cremation or burial.

Cremation (often upon a funeral pyre) was particularly common among the earliest Vikings, who were fiercely pagan and believed the fire's smoke would help carry the deceased to their afterlife. Once cremated, the remains also might be buried, usually in an urn.

For both cremated remains and bodies, burial locations ranged widely, from shallowly-dug graves (often used for women and children) to burial mound s that could hold multiple bodies and groupings of mounds or "grave fields" that served much the same role as cemeteries.

In Norse mythology, boats symbolized safe passage into the afterlife on the same vessel that aided their travels in life, so they played a key role in funeral rites. Some grave mounds were built to resemble ships, with stones used to outline the vessel's shape. For other high-ranked Norsemen, the honors went a step further, and they were buried with their actual boats.

But these types of elaborate boat funerals weren't reserved for just men. One of the most extravagant boat burials honored two women, who likely died around 834 A.D. Known as the "Oseberg ship," it's one of the most well persevered Viking artifacts. While the Vikings were known for the craftsmanship that went into their vessels in general, the size and detail of the Oseberg was exceptional. Seventy feet long and nearly 17 feet wide, the ship had 15 oars on each side, a pine mast more than 30 feet high, and was spacious enough to fit 30 people.

But contrary to popular belief, funeral boats were rarely sent out to sea, likely because the cost of building these legendary longboats was prohibitive. So it's unlikely that there were many ships that were set sail and then set ablaze by fiery arrows shot from the shores.

Regardless of how the body was disposed of, a few rituals remained almost constant. The body was draped in new clothes prepared specifically for the funeral, and a ceremony was held featuring songs, chants, food and alcohol. Tributes and gifts, known as "grave goods" and usually of equal value to the deceased's status, were buried or burned along with the recipient. These goods ran the gamut, from weapons to jewelry to slaves. One Viking site in Flakstad, Norway, contained multiple bodies (some decapitated) in a single grave. Based on analysis of their diets and DNA, it was determined that they were likely slaves, who had been sacrificed to spend eternity with their former masters. Women were often taken in as sex slaves as part of Viking culture, so the idea that they would be sacrificed with their master is feasible.

And according to a report based on accounts from the Middle Ages-traveler Ahmad ibn Fadlan, one instance of the funeral of a Viking chieftain included a sacrificial female slave who was forced to drink copious amounts of alcohol, with large amounts of alcohol, then raped by every man in the village as a tribute to the deceased. From there, she was strangled with a rope, stabbed by a matriarch of the village (known as the Angel of Death), then placed in the boat with her master and set on fire.

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Vikings made their bloody but brief mark on history hundreds of years ago through their nomadic lifestyle and wild practices of raping, pillaging and conquering anything or anyone who crossed their path. These nomads were often seen as savages as they traveled throughout Europe, but the Vikings held a high regard for the life (and death) of their fellow Norsemen.

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The largest-ever study of ancient human DNA, along with the first genome of an individual from the ancient Indus Valley Civilization, reveal in unprecedented detail the shifting ancestry of Central and South Asian populations over time.

The research, published online Sept. 5 in a pair of papers in Science and Cell, also answers longstanding questions about the origins of farming and the source of Indo-European languages in South and Central Asia.

Geneticists, archaeologists and anthropologists from North America, Europe, Central Asia and South Asia analyzed the genomes of 524 never before-studied ancient individuals. The work increased the worldwide total of published ancient genomes by about 25 percent.

By comparing these genomes to one another and to previously sequenced genomes, and by putting the information into context alongside archaeological, linguistic and other records, the researchers filled in many of the key details about who lived in various parts of this region from the Mesolithic Era (about 12,000 years ago) to the Iron Age (until around 2,000 years ago) and how they relate to the people who live there today.

"With this many samples, we can detect subtle interactions between populations as well as outliers within populations, something that has only become possible in the last couple of years through technological advances," said David Reich, co-senior author of both papers and professor of genetics in the Blavatnik Institute at Harvard Medical School.

"These studies speak to two of the most profound cultural transformations in ancient Eurasia -- the transition from hunting and gathering to farming and the spread of Indo-European languages, which are spoken today from the British Isles to South Asia -- along with the movement of people," said Vagheesh Narasimhan, co-first author of both papers and a postdoctoral fellow in the Reich lab. "The studies are particularly significant because Central and South Asia are such understudied parts of the world."

"One of the most exciting aspects of this study is the way it integrates genetics with archaeology and linguistics," said Ron Pinhasi of the University of Vienna, co-senior author of the Science paper. "The new results emerged after combining data, methods and perspectives from diverse academic disciplines, an integrative approach that provides much more information about the past than any one of these disciplines could alone."

"In addition, the introduction of new sampling methodologies allowed us to minimize damage to skeletons while maximizing the chance of obtaining genetic data from regions where DNA preservation is often poor," Pinhasi added.
Language key
Indo-European languages -- including Hindi/Urdu, Bengali, Punjabi, Persian, Russian, English, Spanish, Gaelic and more than 400 others -- make up the largest language family on Earth.

For decades, specialists have debated how Indo-European languages made their way to distant parts of the world. Did they spread via herders from the Eurasian Steppe? Or did they travel with farmers moving west and east from Anatolia (present-day Turkey)?

A 2015 paper by Reich and colleagues indicated that Indo-European languages arrived in Europe via the steppe. The Science study now makes a similar case for South Asia by showing that present-day South Asians have little if any ancestry from farmers with Anatolian roots.

"We can rule out a large-scale spread of farmers with Anatolian roots into South Asia, the centerpiece of the 'Anatolian hypothesis' that such movement brought farming and Indo-European languages into the region," said Reich, who is also an investigator of the Howard Hughes Medical Institute and the Broad Institute. "Since no substantial movements of people occurred, this is checkmate for the Anatolian hypothesis."

One new line of evidence in favor of a steppe origin for Indo-European languages is the detection of genetic patterns that connect speakers of the Indo-Iranian and Balto-Slavic branches of Indo-European. The researchers found that present-day speakers of both branches descend from a subgroup of steppe pastoralists who moved west toward Europe almost 5,000 years ago and then spread back eastward into Central and South Asia in the following 1,500 years.

"This provides a simple explanation in terms of ancient movements of people for the otherwise puzzling shared linguistic features of these two branches of Indo-European, which today are separated by vast geographic distances," said Reich.

A second line of evidence in favor of a steppe origin is the researchers' discovery that of the 140 present-day South Asian populations analyzed in the study, a handful show a remarkable spike in ancestry from the steppe. All but one of these steppe-enriched populations are historically priestly groups, including Brahmins -- traditional custodians of texts written in the ancient Indo-European language Sanskrit.

"The finding that Brahmins often have more steppe ancestry than other groups in South Asia, controlling for other factors, provides a fascinating new argument in favor of a steppe origin for Indo-European languages in South Asia," said Reich.

"This study has filled in a large piece of the puzzle of the spread of Indo-European," said co-author Nick Patterson, research fellow in genetics at HMS and a staff scientist at the Broad Institute of MIT and Harvard. "I believe the high-level picture is now understood."

"This problem has been in the air for 200 years or more and it's now rapidly being sorted out," he added. "I'm very excited by that."
Agriculture origins
The studies inform another longstanding debate, this one about whether the change from a hunting and gathering economy to one based on farming was driven more by movements of people, the copying of ideas or local invention.

In Europe, ancient-DNA studies have shown that agriculture arrived along with an influx of people with ancestry from Anatolia.

The new study reveals a similar dynamic in Iran and Turan (southern Central Asia), where the researchers found that Anatolian-related ancestry and farming arrived around the same time.

"This confirms that the spread of agriculture entailed not only a westward route from Anatolia to Europe but also an eastward route from Anatolia into regions of Asia previously only inhabited by hunter-gatherer groups," said Pinhasi.

Then, as farming spread northward through the mountains of Inner Asia thousands of years after taking hold in Iran and Turan, "the links between ancestry and economy get more complex," said archaeologist Michael Frachetti of Washington University in St. Louis, co-senior author who led much of the skeletal sampling for the Science paper.

By around 5,000 years ago, the researchers found, southwestern Asian ancestry flowed north along with farming technology, while Siberian or steppe ancestry flowed south onto the Iranian plateau. The two-way pattern of movement took place along the mountains, a corridor that Frachetti previously showed was a "Bronze Age Silk Road" along which people exchanged crops and ideas between East and West.

In South Asia, however, the story appears quite different. Not only did the researchers find no trace of the Anatolian-related ancestry that is a hallmark of the spread of farming to the west, but the Iranian-related ancestry they detected in South Asians comes from a lineage that separated from ancient Iranian farmers and hunter-gatherers before those groups split from each other.

The researchers concluded that farming in South Asia was not due to the movement of people from the earlier farming cultures of the west; instead, local foragers adopted it.

"Prior to the arrival of steppe pastoralists bringing their Indo-European languages about 4,000 years ago, we find no evidence of large-scale movements of people into South Asia," said Reich.
First glimpse of the ancestry of the Indus Valley Civilization
Running from the Himalayas to the Arabian Sea, the Indus River Valley was the site of one of the first civilizations of the ancient world, flourishing between 4,000 and 5,000 years ago. People built towns with populations in the tens of thousands. They used standardized weights and measures and exchanged goods with places as far-flung as East Africa.

But who were they?

Before now, geneticists were unable to extract viable data from skeletons buried at Indus Valley Civilization archaeological sites because the heat and volatile climate of lowland South Asia have degraded most DNA beyond scientists' ability to analyze it.

The Cell paper changes this.

After screening more than 60 skeletal samples from the largest known town of the Indus Valley Civilization, called Rakhigarhi, the authors found one with a hint of ancient DNA. After more than 100 sequencing attempts, they generated enough data to reach meaningful conclusions.

The ancient woman's genome matched those of 11 other ancient people reported in the Science paper who lived in what is now Iran and Turkmenistan at sites known to have exchanged objects with the Indus Valley Civilization. All 12 had a distinctive mix of ancestry, including a lineage related to Southeast Asian hunter-gatherers and an Iranian-related lineage specific to South Asia. Because this mix was different from the majority of people living in Iran and Turkmenistan at that time, the authors propose that the 11 individuals reported in the Science paper were migrants, likely from the Indus Valley Civilization.

None of the 12 had evidence of ancestry from steppe pastoralists, consistent with the model that that group hadn't arrived yet in South Asia.

The Science paper further showed that after the decline of the Indus Valley Civilization between 4,000 and 3,500 years ago, a portion of the group to which these 12 individuals belonged mixed with people coming from the north who had steppe pastoralist ancestry, forming the Ancestral North Indians, one of the two primary ancestral populations of present-day people in India. A portion of the original group also mixed with people from peninsular India to form the other primary source population, the Ancestral South Indians.

"Mixtures of the Ancestral North Indians and Ancestral South Indians -- both of whom owe their primary ancestry to people like that of the Indus Valley Civilization individual we sequenced -- form the primary ancestry of South Asians today," said Patterson.

"The study directly ties present-day South Asians to the ancient peoples of South Asia's first civilization," added Narasimhan.

The authors caution that analyzing the genome of only one individual limits the conclusions that can be drawn about the entire population of the Indus Valley Civilization.

"My best guess is that the Indus Valley Civilization itself was genetically extremely diverse," said Patterson. "Additional genomes will surely enrich the picture."

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fossils; origin of life; ancient civilizations; anthropology; ancient dna; early humans; cultures; archaeology

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Largest-ever ancient-DNA study illuminates millennia of South and Central Asian prehistory

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Researchers analyzed the genomes of 524 never before-studied ancient people, including the first genome of an individual from the ancient Indus Valley Civilization. Insights answer longstanding questions about the origins of farming and the source of Indo-European languages in South and Central Asia. The study increases the worldwide total of published ancient genomes by some 25 percent.

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If Wormholes Exist, Could We Really Travel Through Them? - The Crux

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Wormholes make the best shortcuts in the universe. That's true in a literal sense, since the theoretical things can connect distant corners of the cosmos (or even different universes), allowing a traveler to go someplace without having to visit everywhere in between.

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THE spectacular burial seemed to be straight out of the Norse sagas.

It held the remains of a tall Viking warrior. Carefully arrayed alongside the body was a full suite of heavy weaponry. Two expensive horses had been sacrificed as part of the interment ritual.

There was even an elaborate game set, including board and pieces, set carefully on the deceased's lap.

The burial helped set the definition of what a Viking warrior was since it was first discovered near the Swedish town of Birka in the 1880s.

But it turns out there is something out of the ordinary with this hero of the age of plundering long boats.

The American Journal of Physical Anthropology reveals it was a woman in her 30s.

"At Birka, grave Bj 581 was brought forward as an example of an elaborate high-status male warrior grave," the study reads. "This image of the male warrior in a patriarchal society was reinforced by research traditions and contemporary preconceptions. Hence, the biological sex of the individual was taken for granted."

Until now.

"What we have studied was not a Valkyrie from the sagas but a real life military leader, that happens to be a woman," says the leader of the Stockholm and Uppsala Universities study, Charlotte Hedenstierna-Jonson.

The burial was made near the Viking town of Birka in the mid 10th Century. Isotope analysis of her teeth reveals she had been a roamer - moving all about northern Europe in keeping with the legendary Viking wanderlust.

The notion of a Viking warrior woman is not new. Mention is found in Nordic tradition.
Then the highborn lady saw them play the wounding game, she resolved on a hard course and flung off her cloak; she took a naked sword and fought for her kinsmen's lives, she was handy at fighting, wherever she aimed her blows.
- The Greenlandic Poem of Atli

"You can't reach such a high (military) position without having warrior experience, so it's reasonable to believe that she took part in battles," Hedenstierna-Jonson told .

"It was probably quite unusual (for a woman to be a military leader), but in this case, it probably had more to do with her role in society and the family she was from, and that carrying more importance than her gender."

Her DNA tells another, more detailed story.

"The Viking warrior female showed genetic affinity to present-day inhabitants of the British Islands (England and Scotland), the North Atlantic Islands (Iceland and the Orkneys), Scandinavia (Denmark and Norway) and to lesser extent Eastern Baltic Europe (Lithuania and Latvia)," the study reads. "A detailed comparison with modern-day Swedish individuals from across the entire country shows genetic affinities between the female warrior and southern and south-central Swedes."

Study co-author Anna Kjellstrom said the body had attracted questions previously, but tests had proven inconclusive.

"The morphology of some skeletal traits strongly suggests that she was a woman, but this has been the type specimen for a Viking warrior for over a century (which is) why we needed to confirm the sex in any way we could."

The presence of the X chromosome was confirmed in the remains. As was a lack of Y chromosomes.

AN OFFICER AND A GENTLEWOMAN

The weaponry she was buried with denoted her as an accomplished warrior. Her high status was inferred from the burial of two horses.

"The gaming set indicates that she was an officer", says Hedenstierna-Jonson, "someone who worked with tactics and strategy and could lead troops in battle".

So does the simple presence of weapons make her a warrior, the study asks.

"The interpretation of grave goods is not straight forward, but it must be stressed that the interpretation should be made in a similar manner regardless of the biological sex of the interred individual. Furthermore, the exclusive grave goods and two horses are worthy of an individual with responsibilities concerning strategy and battle tactics."
The study points out this grave brings the total of known Viking warrior women to three.

"The female Viking warrior was part of a society that dominated 8th to 10th century northern Europe," the study concludes. "Our results - that the high-status grave Bj 581 on Birka was the burial of a high ranking female Viking warrior - suggest that women, indeed, were able to be full members of male dominated spheres. Questions of biological sex, gender and social roles are complex and were so also in the Viking Age."

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Iconic Viking warrior revealed to have been a woman

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THE spectacular burial seemed to be straight out of the Norse sagas. It held the remains of a tall Viking warrior. Carefully arrayed alongside the body was a full suite of heavy weaponry. Two expensive horses had been sacrificed as part of the interment ritual.

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View Slideshow

Lake Van is the largest lake in Turkey - but that isn't its only claim to fame. Van Yüzüncü Yil University archaeologists and a team of divers recently discovered an underwater fortress there. The ancient nation of Urartu could have built the castle roughly around 3,000 years ago during the Iron Age.

The team explored the lake based on local rumors of ancient ruins, despite other archaeologists familiar with the area telling them they probably wouldn't find much. But the rumors turned out to be correct: diving team head Tahsin Ceylan told Turkey's newswire service Andalou Agency the archaeological site is around one kilometer, or a little over half a mile, large. The fortress walls that they can see are between 10 to 13 feet in size.
Related: Haunting drowned figures send a chilling message in Europe's first undersea sculpture museum
Some of the remains are loose piles of stones, others are smooth walls, according to National Geographic. Visual assessments led the team to estimate the underwater castle is around 3,000 years old. It would have been built when the lake's water level was hundreds of meters lower. According to ScienceAlert, Lake Van's water levels have fluctuated dramatically throughout the years.

Urartu, a kingdom that flourished between the ninth and sixth centuries BCE, was centered around Lake Van, according to the Metropolitan Museum of Art. Other archaeological remains in the area, some higher than the current shoreline, are also the subject of study. And archaeologists and divers plan to return to the lake the learn more about the recently found sunken fortress. They're not yet sure how deep the walls might be buried in lake floor sediment, and they hope to learn more about the people who inhabited the castle.

Via National Geographic and ScienceAlert
Images via National Geographic on YouTube

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3,000-year-old underwater castle discovered in Turkey's largest lake

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View Slideshow Lake Van is the largest lake in Turkey - but that isn't its only claim to fame. Van Yüzüncü Yil University archaeologists and a team of divers recently discovered an underwater fortress there. The ancient nation of Urartu could have built the castle roughly around 3,000 years ago during the Iron Age.

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A Sample of Specialty Moons

When the media start talking about the "super blood moon," people often get confused. But it's not all sensationalism - these terms tell us something about the moon's current state.

Supermoon: A full moon when it's physically closest to Earth, making it appear 14 percent bigger than when it's at its smallest and farthest. Despite the hype, though, human eyes can't actually tell the difference.

Blue moon: Originally, this was the third full moon in a season that has four full moons. (Three is normal.) Within the past century, it has shifted to mean the second full moon in one calendar month. Both are rare.

Blood moon: The part of a total lunar eclipse when the moon enters Earth's shadow. A partially eclipsed moon simply looks dark, like something has taken a bite out of it. But during totality, all of Earth's sunsets and sunrises trickle through our atmosphere to tinge the moon's shadowed surface.

Solar eclipse: This term doesn't include the word moon, but it's when our satellite aligns between Earth and the sun at just the right angle to cast a shadow on Earth's surface. Like lunar eclipses, this phenomenon is possible only because the sun and moon appear the same size in Earth's sky; if the moon were closer (as it once was) or farther (as it will be), no eclipses could occur.

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Earth's Moon: The Basics of its Origin, Evolution and Exploration

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A Sample of Specialty Moons When the media start talking about the "super blood moon," people often get confused. But it's not all sensationalism - these terms tell us something about the moon's current state. Supermoon: A full moon when it's physically closest to Earth, making it appear 14 percent bigger than when it's at its smallest and farthest.

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Using numbers scrawled by Bronze Age merchants on 4,000-year-old clay tablets, a historian and three economists have developed a novel way to pinpoint the locations of lost cities of the ancient world.

The ancient city of Kanesh, located in the middle of modern-day Turkey, was a hub of trade in the Anatolian region four millennia ago. Modern-day archaeologists have unearthed artifacts from the city, including more than 23,000 cuneiform texts, inscribed in clay by ancient Assyrian merchants.

The texts themselves are mostly "business letters, shipment documents, accounting records, seals and contracts," according to the working paper by Gojko Barjamovic, Thomas Chaney, Kerem A. Cosar and Ali Hortacsu. Barjamovic is an expert in the history of Assyria, the ancient Middle Eastern kingdom founded near the Tigris River in what is present-day Iraq. His co-authors are economists from, respectively, the Paris Institute of Political Studies, the University of Virginia and the University of Chicago.

A typical passage from the clay tablets, translated by the team, reads something like this:

From Durhumit until Kaneš I incurred expenses of 5 minas of refined (copper), I spent 3 minas of copper until Wahšušana, I acquired and spent small wares for a value of 4 shekels of silver

Most tantalizing to archaeologists are the mentions in the tablets of ancient cities and settlements - some of which have been located, others of which remain unknown. In the record above, for instance, while Kaneš (Kanesh) has been located and excavated. Durhumit is, at present, lost to history.

Traditionally, historians and archaeologists have analyzed texts like these for bits of qualitative information that might locate a site - descriptions of landscape features, for instance, or indications of distance or direction from other, known cities.

But Barjamovic and his co-authors had a different idea: What if they analyzed the quantitative data contained in the tablets instead? In the passage above, for instance, you have a record of three separate cargo shipments: Durhumit to Kanesh, Kanesh to Wahshushana, and Durhumit to Wahshushana.

If you analyze thousands of tablets and tally up each record of a cargo shipment contained therein, you end up with a remarkably comprehensive picture of trade among the cities around Kanesh 4,000 years ago. Barjamovic did exactly that, translating and parsing 12,000 clay tablets, extracting information on merchants' trade itineraries.

What they had, in the end, was a record of hundreds of trade interactions among a total of 26 ancient cities: 15 whose locations were known and 11 that remain lost.

Here's where things get really interesting: In the ancient world, trade was strongly dependent on geographic distance. Moving goods from Point A to Point B was a lot more difficult at a time when roads were rough, goods had to be transported on the backs of donkeys and robbers lurked everywhere.

Cities located closer together traded more, while those farther apart traded less. This is the key insight driving the entire paper. Let's say we have an ancient city, such as Kanesh, that we know the location of. We also have two lost cities, Kuburnat and Durhumit. If we know Kanesh traded more with Kuburnat than with Durhumit, we can reasonably assume that Kuburnat is closer to Kanesh than Durhumit is.

The figure above is a conceptual illustration of this idea. Kanesh is in the center, Kuburnat is somewhere in the inner light-blue region, and Duhurmit is somewhere farther out, in the dark-blue area.

If you have decent data on trade volume (from, say, thousands of clay tablets), you can do one better than this: You can actually plug the trade data into an algorithm that uses other pieces of known data, such as commodity prices and population size, to estimate the distance between two given cities, given the volume of trade between them.

Updating our example illustration, you can see that if we know the rough distance between two cities, we can narrow our concentric circles down to concentric rings.

That still leaves a large area to search if we're trying to find these lost cities. But recall: the clay tablet data set includes trade volumes for 14 other known cities in addition to Kanesh. We can run our trade algorithm for any given lost city, such as Durhumit, against any other city we already know the location of. That gives us an estimate of the distance to Durhumit from each of those cities.

If a number of those distance estimates overlap in the same region, that's a pretty strong indicator that Durhumit would have been located in that region.

In the end, the trade data contained on 12,000 ancient clay tablets allowed Barjamovic and his co-authors to estimate the locations of the 11 lost cities mentioned therein. As a sanity check, they mapped their own estimates against some qualitative guesses produced by historians over the years. In some cases, the qualitative and quantitative estimates were in precise agreement. In others, the quantitative model lends credence to one historical assessment vs. another. In others, the model suggests that the historians previously got it completely wrong.

"For a majority of cases, our quantitative estimates are remarkably close to qualitative proposals made by historians," the authors conclude. "In some cases where historians disagree on the likely site of lost cities, our quantitative method supports the suggestions of some historians and rejects that of others."

As a final check, the authors ran the model against the location of known ancient cities to see whether its results matched the actual archaeological record.

One two out of three of the known cities they tested against, the model nailed it. But it whiffed on the third.

The authors suspect their algorithm performs better for cities located near the center of the Assyrian trade network. The "estimation of the location of lost cities is reliable for central cities, but less precise for peripheral cities," they write. Whether you're a Bronze Age merchant of a modern-day economist, long distances remain treacherous.

Still, the authors say their approach for finding lost cities can be used to supplement more traditional methods, helping historians fill in gaps of knowledge in the archaeological record. Beyond that, the paper is a fascinating illustration of how modern knowledge can breathe new life into numbers inscribed on clay tablets 4,000 years ago.

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Analysis | Ancient data, modern math and the hunt for 11 lost cities of the Bronze Age

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Using numbers scrawled by Bronze Age merchants on 4,000-year-old clay tablets, a historian and three economists have developed a novel way to pinpoint the locations of lost cities of the ancient world. The ancient city of Kanesh, located in the middle of modern-day Turkey, was a hub of trade in the Anatolian region four millennia ago.