Lifeboat Foundation

Nontrivial band topology can combine with magnetic order in a magnetic topological insulator to produce exotic states of matter such as quantum anomalous Hall (QAH) insulators and axion insulators. An aim of condensed matter physics is to find new materials with useful properties and apply quantum mechanics to study them. The field has allowed physicists to better understand the uses of magnets for hard disk data storage, computer displays and other technologies. The recent discovery of topological insulators have attracted broad interest and researchers predict that the interplay between ferromagnetism and the topological insulator state can realize a range of exotic quantum magnetic phenomena of interest in fundamental physics and device applications.

In a new report, Yujun Deng and a research team at the departments of physics and quantum matter physics in China, probed quantum transport in a thin flake MnBi₂Te₄ topological insulator, with intrinsic magnetic order. The ferromagnetic layers coupled anti-parallelly to each other in the atomically thin MnBi₂Te₄ layered van der Waals crystal. However, the sample became ferromagnetic when it contained an odd number of septuple layers. The research team observed the zero-field QAH effect in a five-septuple-layer specimen at 1.4 Kelvin. The results established MnBi₂Te₄ as an ideal platform to explore exotic topological phenomena with spontaneously broken time-reversal symmetry. The work is now published on Science.

Topological materials distinctly contain topologically protected quantum states that are robust against local distresses. For instance, in a topological insulator (TI) such as bismuth telluride (Bi₂Te₃), the bulk band topology can guarantee the existence of two-dimensional (2-D) surface states with gapless Dirac dispersion. By introducing magnetism into the initially time-reversal invariant topological insulators (TIs), scientists can induce profound changes in their electronic structure. For example, to experimentally observe the QAH effect in chromium-doped (Bi, Sb)₂Te₃, physicists had to precisely control the ratio of multiple elements in a non-stoichiometric material. Fine-tuning the material required reconciling conflicting demands and therefore, researchers had to precisely quantize the anomalous Hall effect only at temperatures up to T = 2 K, far below the Curie temperature and exchange gap in the material.

Brain-computer interfaces (BCIs) are tools that can connect the human brain with an electronic device, typically using electroencephalography (EEG). In recent years, advances in machine learning (ML) have enabled the development of more advanced BCI spellers, devices that allow people to communicate with computers using their thoughts.

So far, most studies in this area have focused on developing BCI classifiers that are faster and more reliable, rather than investigating their possible security vulnerabilities. Recent research, however, suggests that machine learning algorithms can sometimes be fooled by attackers, whether they are used in computer vision, speech recognition, or other domains. This is often done using adversarial examples, which are tiny perturbations in data that are indistinguishable by humans.

Researchers at Huazhong University of Science and Technology have recently carried out a study investigating the security of EEG-based BCI spellers, and more specifically, how they are affected by adversarial perturbations. Their paper, pre-published on arXiv, suggests that BCI spellers are fooled by these perturbations and are thus highly vulnerable to adversarial attacks.

3D-printing innovations in recent years have brought a sea change in the fabrication of everything from automobile parts to human bio-tissues.

VICE’s Krishna Andavolu delves into the cutting-edge research behind what’s being called the next industrial revolution, meeting the scientists and entrepreneurs pushing the boundaries of manufacturing, material science, and even space exploration.

Continue reading “3D Printing Is Changing the World | VICE on HBO” »

New observations of Pallas reveal a strange, crater-rich world.

A favorite theme of science fiction is “the portal”—an extraordinary opening in space or time that connects travelers to distant realms. A good portal is a shortcut, a guide, a door into the unknown. If only they actually existed…

It turns out that they do, sort of, and a NASA-funded researcher at the University of Iowa has figured out how to find them.

“We call them X-points or electron diffusion regions,” explains plasma physicist Jack Scudder of the University of Iowa. “They’re places where the magnetic field of Earth connects to the magnetic field of the Sun, creating an uninterrupted path leading from our own planet to the sun’s atmosphere 93 million miles away.”

Crisis Text Line used artificial intelligence to pinpoint the things people text when they’re thinking of suicide.

WASHINGTON — Northrop Grumman was awarded a $253.5 million contract by the U.S. Space Force to develop a cyber-secure communications payload that could be deployed on a military or commercial satellite.

The U.S. Space Force’s Space and Missile Systems Center announced Feb. 12 that Northrop Grumman was the first vendor selected to build a prototype payload under the Protected Tactical Satellite Communications (PTS) program that the U.S. Air Force started in 2018.

As many as four prototype payloads will be funded under the PTS program. Two payloads will be selected to launch in 2024 for on-orbit demonstrations that will last three to five years.

Glioblastomas are relentless, hard-to-treat, and often lethal brain tumors. Yale scientists have enlisted a most unlikely ally in efforts to treat this form of cancer — elements of the Ebola virus.

“The irony is that one of the world’s deadliest viruses may be useful in treating one of the deadliest of brain cancers,” said Yale’s Anthony van den Pol, professor of neurosurgery, who describes the Yale efforts Feb. 12 in the Journal of Virology.

The approach takes advantage of a weakness in most cancer tumors and also of an Ebola defense against the immune system response to pathogens.

Plant pathogens elicit an immune response through effector proteins. In turn, plant genomes encode genes that determine species-specific recognition of these effectors by a process known collectively as effector-triggered immunity (ETI). By examining a range of strains of the pathogen Pseudomonas syringae that infect the model plant Arabidopsis thaliana, Laflamme et al. generated a P. syringae Type III Effector Compendium (PsyTEC) and in turn identified the genes responsible for ETI in Arabidopsis. This pan-genome analysis revealed that relatively few A. thaliana genes are responsible for recognizing the majority of P. syringae effectors. These results provide insight into why most pathogenic microbes only infect specific plant species.

Science, this issue p. 763

Effector-triggered immunity (ETI), induced by host immune receptors in response to microbial effectors, protects plants against virulent pathogens. However, a systematic study of ETI prevalence against species-wide pathogen diversity is lacking. We constructed the Pseudomonas syringae Type III Effector Compendium (PsyTEC) to reduce the pan-genome complexity of 5127 unique effector proteins, distributed among 70 families from 494 strains, to 529 representative alleles. We screened PsyTEC on the model plant Arabidopsis thaliana and identified 59 ETI-eliciting alleles (11.2%) from 19 families (27.1%), with orthologs distributed among 96.8% of P. syringae strains. We also identified two previously undescribed host immune receptors, including CAR1, which recognizes the conserved effectors AvrE and HopAA1, and found that 94.7% of strains harbor alleles predicted to be recognized by either CAR1 or ZAR1.