Grambank shows the diversity of the world's languages

Linguists have long been interested in language variation. What are common or universal patterns across languages? What limits the possible variation between them? Grambank, the world's largest and most comprehensive database of language structure, enables researchers to answer some of these questions.

Grambank was constructed in an international collaboration between the Max Planck institutes in Leipzig and Nijmegen, the Australian National University, the University of Auckland, Harvard University, Yale University, the University of Turku, Kiel University, Uppsala University, SOAS, the Endangered Languages Documentation Programme, and over a hundred scholars from around the world. Grambank's coverage spans 215 different language families and 101 isolates from all inhabited continents. "The design of the feature questionnaire initially required numerous revisions in order to encompass many of the diverse solutions that languages have evolved to code grammatical properties," says Hedvig Skirgård, who coordinated much of the coding and is the lead author of the study.

Limits on variation

The team settled on 195 grammatical properties, ranging from word order to whether or not a language has gendered pronouns. For instance, many languages have separate pronouns for 'he' and 'she', but some also have male and female versions of 'I' or 'you'. The possible 'design space' would be enormous if grammatical properties were to vary freely. Limits on variation could be related to cognitive principles rooted in memory or learning, rendering some grammatical structures more likely than others. Limits could also be related to historical 'accidents', such as descent from a common language or contact with other languages.

The researchers discovered much greater flexibility in the combination of grammatical features than many theorists have assumed. "Languages are free to vary considerably in quantifiable ways, but not without limits," explains Stephen Levinson, Director emeritus of the Max Planck Institute for Psycholinguistics in Nijmegen and one of the founders of the Grambank project. "A sign of the extraordinary diversity of the 2400 languages in our sample is that only five of them occupy the same location in design space (share the same grammatical properties)."

Languages show much greater similarity to those with a common ancestor than those they are in contact with. "Genealogy generally trumps geography," says Russell Gray, Director of the Department of Linguistic and Cultural Evolution and senior author of the study. "Nevertheless, if processes of linguistic evolution and diversification were run again from the beginning, there would still be some resemblance to what we now have. The constraints of human cognition mean that, while there is a great deal of historical contingency in the organisation of grammatical structures, there are regular patterns as well."

Diversity under threat

"The extraordinary diversity of languages is one of humanity's greatest cultural endowments," concludes Levinson. "This endowment is under threat, especially in some areas such as Northern Australia, and parts of South and Northern America. Without sustained efforts to document and revitalise endangered languages, our linguistic window into human history, cognition and culture will be seriously fragmented."

Read more at Science Daily

Evolution of wheat spikes since the Neolithic revolution

Around 12,000 years ago, the Neolithic revolution radically changed the economy, diet and structure of the first human societies in the Fertile Crescent of the Near East. With the beginning of the cultivation of cereals -- such as wheat and barley -- and the domestication of animals, the first cities emerged in a new social context marked by a productive economy. Now, a study published in the journal Trends in Plant Science and co-led by the University of Barcelona, the Agrotecnio centre and the University of Lleida, analyses the evolution of wheat spikes since its cultivation began by the inhabitants of ancient Mesopotamia -- the cradle of agriculture in the world -- between the Tigris and the Euphrates.

The authors of the study are Rut Sánchez-Bragado and Josep Lluís Araus-Ortega, from the UB Faculty of Biology and Agrotecnio-UdL; Gustavo A. Slafer, ICREA researcher at the UdL School of Agrifood and Forestry Science and Engineering, and Gemma Molero, from the International Maize and Wheat Improvement Center in Mexico, currently a researcher at KWS Seeds Inc.

A cereal that changed human history

The cultivation of wheat -- a grass that became basic food -- represented a turning point in the progress of human civilisation. Today it is the world's most important crop in terms of food security, but EU data warn that the impact of climate change could significantly increase its price and modify its production process in certain areas of the world.

Throughout the domestication process of wheat, the plant phenotype has undergone both rapid (within a few hundred years) and slow (thousands of years) changes, such as the weakening of the rachis, the increase in seed size, and the reduction or disappearance of the awns. In particular, awned and awnless wheat varieties are found all over the world, although the latter tend to be abundant in regions with arid climates, especially during the final stages of cultivation in late spring, a condition typical of Mediterranean environments.

"It is important to conduct studies that show which wheat varieties are best adapted to different environmental growing conditions, especially in a context of climate change. Studying the past retrospectively can give us an idea of the evolution of wheat cultivation over the millennia since agriculture appeared in ancient Mesopotamia," says Rut Sánchez-Bragado, first author of the study, who got a PhD at the UB.

"Awns are organs of the spike that have traditionally been associated with the plant's adaptations to drought conditions," says Josep Lluís Araus, professor at the Department of Evolutionary Biology, Ecology and Environmental Sciences of the Faculty of Biology.

"However, archaeological and historical records show that the wheat spike has existed predominantly with awns for more than ten millennia after the domestication of wheat. It is not until the last millennium that evidence shows in many cases the absence of awns, indicating a selection by farmers -- probably in an undirected way -- against this organ," stresses Araus, one of the most cited authors in the world according to Clarivate Analytics' Highly Cited Researchers (2022).

"The role of wheat awns in their performance remains controversial despite decades of studies," says researcher Gustavo A. Slafer, corresponding author of the study.

Spike awns: beneficial for the plant?

Is the presence of awns on the spike beneficial for the plant and the crops? Although there is no scientific consensus, "everything suggests that in conditions where the plant does not suffer from water stress, the extra photosynthetic capacity of the awns does not compensate for other potential negative effects (reduced susceptibility to fungal diseases, limitation in the total number of large ones that an ear supports, etc.)," says Araus.

"However, in wetter climates the awns accumulate moisture and can promote the spread of diseases," says Rut Sánchez-Bragado. "So, as the world's population is continuously growing, it is necessary to investigate the role of the awned spikes in the changing conditions of our climate in order to meet the world's demand for a primary food commodity such as wheat."

Read more at Science Daily

International team observes innermost structure of quasar jet

An international team of scientists has observed the narrowing of a quasar jet for the first time by using a network of radio telescopes across the world. The results suggest that the narrowing of the jet is independent of the activity level of the galaxy which launched it.

Nearly every galaxy hosts a supermassive black hole in its center. In some cases, enormous amounts of energy are released by gas falling towards the black hole, creating a phenomenon known as a quasar. Quasars emit narrow, collimated jets of material at nearly the speed of light. But how and where quasar jets are collimated has been a long-standing mystery.

An international team led by Hiroki Okino, a graduate student at the University of Tokyo, and including members from the National Astronomical Observatory of Japan (NAOJ), the Massachusetts Institute of Technology, Kogakuin University, Hachinohe National College of Technology, and Niigata University, captured an image with the highest angular resolution to date that shows the deepest part of the jet in a bright quasar known as 3C 273. The team found that the jet flowing from the quasar narrows down over a very long distance. This narrowing part of the jet continues incredibly far, well beyond the area where the black hole's gravity dominates. The results show that the structure of the jet is similar to jets launched from nearby galaxies with a low luminosity active nucleus. This would indicate that the collimation of the jet is independent of the activity level in the host galaxy, providing an important clue to unravelling the inner workings of jets.

Read more at Science Daily

New insights about surface, structure of asteroid Bennu

When NASA's OSIRIS-REx spacecraft collected samples from asteroid Bennu's surface in 2020, forces measured during the interaction provided scientists with a direct test of the poorly understood near-subsurface physical properties of rubble-pile asteroids. Now, a Southwest Research Institute-led study has characterized the layer just below the asteroid's surface as composed of weakly bound rock fragments containing twice the void space as the overall asteroid.

"The low gravity of rubble-pile asteroids such as Bennu weakens its near-subsurface by not compressing the upper layers, minimizing the influence of particle cohesion," said SwRI's Dr. Kevin Walsh, lead author of a paper about this research published in the journal Science Advances. "We conclude that a low density, weakly bound subsurface layer should be a global property of Bennu, not just localized to the contact point."

Fitting its designation as a "rubble-pile asteroid," Bennu is a spheroidal collection of rock fragments and debris 1,700 feet in diameter and held together by gravity. It is thought to have been formed after a collision involving a larger main-asteroid-belt object. Rocks are scattered across its heavily cratered surface, indicating that it has had a rough-and-tumble existence since being liberated from its much larger parent asteroid some millions or billions of years ago.

The goal of OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) mission is to collect and return at least 60 grams of surface material from Bennu and deliver it to Earth in 2023. Sample collection activities provided additional insights.

According to Walsh, researchers involved in the OSIRIS-REx mission have so far measured Bennu's thermal properties and craters to estimate the strength and porosity of discrete particles of rubble-pile asteroids. The ensemble of particles, or regolith, at an asteroid's surface controlling and influencing long-term evolution have not yet been probed directly until now.

Before, during, and after the sampling event, the Sample Acquisition Verification Camera (SamCam) of the OSIRIS-REx Camera Suite captured images looking at the Touch-and-Go Sample Acquisition Mechanism (TAGSAM) robotic arm.

"The SamCam images bracketing the moment of contact show the contact caused considerable disturbance at the sample site," said Dr. Ron Ballouz, a co-author from Johns Hopkins University's Applied Physics Laboratory. "Nearly every visible particle is moved or re-oriented at all points along the circumference of TAGSAM up to a 15-inch radius."

These SamCam images showed the downward force of TAGSAM lifted a nearly 16-inch rock. Though strong enough to withstand breaking, the rock was re-oriented and small debris lofted off its surface. The mobility of these millimeter-scale particles under relatively weak forces suggests minimal cohesive bonding with the surface of the larger rock.

Scientists have theorized that the average regolith particle size increases as asteroid size decreases, because larger bodies retain smaller materials due to a higher surface gravity. The team then compared Bennu to similar rubble-pile asteroids.

"We discovered a dichotomy between the rough, boulder-covered surfaces of Bennu and Ryugu versus Itokawa, which includes ponds of smaller particles across 20% of its surface," Walsh said. "This could have several explanations, including that the latter's near-surface has compressed enough to frustrate these microparticles percolating into the interior or perhaps the granular deposits are subsurface layers revealed by a recent disruptive reorganization of the body."

Read more at Science Daily