Integration leads to leap in tech for forest inventory and management

Credit: Purdue University

Through integration of aerial and ground-based mobile mapping sensors and systems, a team of Purdue digital forestry researchers has used advanced technology to locate, count and measure over a thousand trees in a matter of hours.

“The machines are counting and measuring each tree – it is not an estimation using modeling, it is a true forest inventory,” said Songlin Fei, the Dean's Remote Sensing Chair and professor of forestry and natural resources and leader of Purdue University’s Digital Forestry initiative. “This is a groundbreaking development on our path to using technology for a quick, accurate inventory of the global forest ecosystem, which will improve our ability to prevent forest fires, detect disease, perform accurate carbon counting and make informed forest management decisions.”

The technology uses manned aircraft, unmanned drones and backpack-mounted systems. The systems integrate cameras with light detection and ranging units, or LiDAR, together with navigation sensors, including integrated global navigation satellite systems (GNSS) and inertial navigation systems (INS). A Purdue team led by Ayman Habib, Thomas A. Page Professor of Civil Engineering and head of Purdue's Digital Photogrammetry Research Group, who co-led the project with Fei, designed and created the systems.

Exotic tree plantations can disturb local wildlife, researchers find

Canthon fulgidus, a roller-dung beetle species in the study region
Credit: Dr Filipe França

Initiatives using non-native tree species can impact tropical insects in neighboring forests, according to an international study.

Scientists at the University of Bristol and Federal University of Western Pará, in Brazil have found that Eucalyptus plantation edge effects radiates up to 800 meters into the interior of nearby Amazonian forests, when applied to ecologically important dung beetles.

As the world seeks to mitigate human-induced climate change, planted forests have become widespread restoration strategies across the globe. However, the findings, published today in Forest Ecology and Management, suggest that while well-intentioned, exotic tree plantations can have a wider influence on the native biodiversity of hyperdiverse tropical forests.

In ecology, edge effect research investigates how biological populations or communities change at the boundary of two or more habitats.

Yolk-Shell Nanocrystals with Movable Gold Yolk: Next Generation of Photocatalysts

The synthesis of yolk-shell nanostructures involves sulfidation on an Au@Cu2O core-shell nanocrystal template to convert the shell composition to various metal sulphides.
Credit: Tokyo Institute of Technology

Owing to their unique permeable, hollow shell structures with inner, movable cores, yolk-shell nanocrystals are suitable for a wide variety of applications. Yolk-shell nanocrystals consisting of a gold core with various semiconductor shells have been developed by Tokyo Tech researchers, using a novel sequential ion-exchange process. These metal-semiconductor yolk-shell nanocrystals can serve as highly effective photocatalysts for many applications.

Yolk-shell nanocrystals are unique materials with fascinating structural properties, such as a permeable shell, interior void space, and movable yolk. These nanocrystals are suitable for a variety of applications, depending on the choice of materials used for their fabrication.

For example, if the inner surface of their shells are reflective, yolk-shell nanocrystals can make for a reliable photovoltaic device. A mobile core can can act as a stirrer, capable of mixing solutions held within the shell. The inner and outer surfaces of the shell provide plenty of active sites for reactions, and the yolk-shell structure's fascinating properties (a result of electronic interactions and charge-transfer between the surfaces of the structure) make these nanocrystals ideal for photocatalysis applications. Understandably, yolk-shell nanocrystals have earned the attention of researchers worldwide.

New Study Deepens Understanding of How Animals See, and What Colors

 Researchers determined that animals adapted to land see more colors than animals adapted to water. Animals adapted to open terrestrial habitats see a wider range of colors than animals adapted to forests.
 Credit: Artwork by Matt Murphy

Gathering vision data for hundreds of vertebrates and invertebrates, U of A biologists have deepened scientists’ understanding of animal vision, including the colors they see.

Researchers have determined that animals adapted to land are able to see more colors than animals adapted to water. Animals adapted to open terrestrial habitats see a wider range of colors than animals adapted to forests.

However, evolutionary history — primarily the difference between vertebrates and invertebrates — significantly influences which colors a species sees. Invertebrates see shorter wavelengths of light, compared to vertebrates.

Biological sciences doctoral student Matt Murphy and assistant professor Erica Westerman recently published these findings in Proceedings of the Royal Society B, a top British scientific journal. Their article, “Evolutionary history limits species’ ability to match color sensitivity to available habitat light,” explains how environment, evolution and, to some extent, genetic composition influence how and what colors animals see.

Copper makes seed pods explode

A stiff polymer called lignin (stained red) is deposited in a precise pattern in the cell walls of exploding seed pods. Researchers identified three laccase enzymes required to form this lignin. No lignin forms in the cell wall (stained blue) when all three genes are knocked out by CRISPR/Cas9 gene editing. 
Credit: Miguel Pérez Antón

Plants have evolved numerous strategies to spread their seeds widely. Some scatter their seeds to the wind, while others tempt animals and birds to eat their seed-filled fruits. And a few rare plants – such as the popping cress Cardamine hirsuta – have evolved exploding seed pods that propel their seeds in all directions. In their new study published in PNAS, Angela Hay and colleagues – from the Max Planck Institute for Plant Breeding Research in Cologne, Germany – investigate what genes control the mechanical structure of these exploding seed pods. Their findings show that a key micronutrient – copper – is essential for laying down a precise pattern of lignin in the seed pods. Lignin is an abundant plant polymer found in lignocellulose, the main structural material in plants. It is present in plant cells walls and is responsible for making wood stiff.

C. hirsuta seed pods consist of two, long valves. When the seeds are ready for dispersal, these valves rapidly separate and coil back, firing seeds out across a large area. The secret to these pods explosive nature is their unique mechanical design, which features three stiff rods of lignin connected by hinges. These hinges are crucial for the explosive release of potential energy stored in the pod. To create these hinged structures, lignin is deposited in a precise pattern in a single layer of seed pod cells, called endocarpb.

How animals reach their correct size

The development of hundreds of C. elegans individuals growing in micro-chambers was recorded with time-lapse microscopy.
Credit: Towbin Lab

Adults of the same species usually differ very little in their size. A team from the University of Bern and the Friedrich Miescher Institute for Biomedical Research (FMI) in Basel has now discovered a mechanism that ensures such size uniformity. The research using nematodes showed that the speed of growth determines the speed of a genetic clock that times development. Thereby, individuals that grow slowly are given more time to grow and can reach the same adult body size.

By and large, individuals of the same species grow to the same size. This uniformity in size is astounding, since intrinsic randomness in developmental processes and in environmental conditions produce substantial differences in how fast individuals grow. Moreover, because animal growth is often exponential, even small differences in growth can amplify to large differences in size. How do animals nevertheless make sure to reach the correct size?

Lab Earthquakes Show How Grains at Fault Boundaries Lead to Major Quakes

A three-dimensional visualization shows how rock gouge can arrest a rupture (in red) but, with a combination of dynamic stressing and dynamic weakening, will ultimately re-nucleate the rupture shortly thereafter (in blue).
Credit: Vito Rubino / California Institute of Technology

By simulating earthquakes in a lab, Caltech engineers have provided strong experimental support for a form of earthquake propagation now thought responsible for the magnitude-9.0 earthquake that devastated the coast of Japan in 2011.

Along some fault lines, which are the boundaries of tectonic plates, a fine-grained gravel is formed as the plates grind against one another. The influence of this gravel on earthquakes has long been the subject of scientific speculation. In a new paper appearing in the journal Nature the Caltech researchers show that the fine gravel, known as rock gouge, first halts earthquake propagation, but then triggers the rebirth of earthquakes to generate powerful ruptures.

"Our novel experimental approach has enabled us to look into the earthquake process up close, and to uncover key features of rupture propagation and friction evolution in rock gouge," says Vito Rubino, research scientist and lead author of the Nature paper. "One of the main findings of our study is that fault sections previously thought to act as barriers against dynamic rupture may in fact host earthquakes, as a result of the activation of co-seismic friction weakening mechanisms."

Hallucinating to better text translation

Source/Credit: MIT

As babies, we babble and imitate our way to learning languages. We don’t start off reading raw text, which requires fundamental knowledge and understanding about the world, as well as the advanced ability to interpret and infer descriptions and relationships. Rather, humans begin our language journey slowly, by pointing and interacting with our environment, basing our words and perceiving their meaning through the context of the physical and social world. Eventually, we can craft full sentences to communicate complex ideas.

Similarly, when humans begin learning and translating into another language, the incorporation of other sensory information, like multimedia, paired with the new and unfamiliar words, like flashcards with images, improves language acquisition and retention. Then, with enough practice, humans can accurately translate new, unseen sentences in context without the accompanying media; however, imagining a picture based on the original text helps.

This is the basis of a new machine learning model, called VALHALLA, by researchers from MIT, IBM, and the University of California at San Diego, in which a trained neural network sees a source sentence in one language, hallucinates an image of what it looks like, and then uses both to translate into a target language. The team found that their method demonstrates improved accuracy of machine translation over text-only translation. Further, it provided an additional boost for cases with long sentences, under-resourced languages, and instances where part of the source sentence is inaccessible to the machine translator.

Bumps could smooth quantum investigations

Stamping or growing 2D materials onto a patterned surface could create models for 1D systems suitable for the exploration of quantum effects, according to a new theory by Rice University engineers. The “bumps” would manipulate the flow of electrons into bands that mimic 1D semiconductors.
Credit: Yakobson Research Group/Rice University

Atoms do weird things when forced out of their comfort zones. Rice University engineers have thought up a new way to give them a nudge.

Materials theorist Boris Yakobson and his team at Rice’s George R. Brown School of Engineering have a theory that changing the contour of a layer of 2D material, thus changing the relationships between its atoms, might be simpler to do than previously thought.

While others twist 2D bilayers -- two layers stacked together -- of graphene and the like to change their topology, the Rice researchers suggest through computational models that growing or stamping single-layer 2D materials on a carefully designed undulating surface would achieve “an unprecedented level of control” over their magnetic and electronic properties.

They say the discovery opens a path to explore many-body effects, the interactions between multiple microscopic particles, including quantum systems.

The paper by Yakobson and two alumni, co-lead author Sunny Gupta and Henry Yu, of his lab appears in Nature Communications.

Breakthrough paves way for photonic sensing at the ultimate quantum limit

Photonic chip with a microring resonator nanofabricated in a commercial foundry.
Photo credit: Joel Tasker, QET Labs

A Bristol-led team of physicists has found a way to operate mass manufacturable photonic sensors at the quantum limit. This breakthrough paves the way for practical applications such as monitoring greenhouse gases and cancer detection.

Sensors are a constant feature of our everyday lives. Although they often go unperceived, sensors provide critical information essential to modern healthcare, security, and environmental monitoring. Modern cars alone contain over 100 sensors and this number will only increase.

Quantum sensing is poised to revolutionize today's sensors, significantly boosting the performance they can achieve. More precise, faster, and reliable measurements of physical quantities can have a transformative effect on every area of science and technology, including our daily lives.

However, the majority of quantum sensing schemes rely on special entangled or squeezed states of light or matter that are hard to generate and detect. This is a major obstacle to harnessing the full power of quantum-limited sensors and deploying them in real-world scenarios.