Menu

Blog

Page 7281

Jul 21, 2020

Temporal aiming with temporal metamaterials

Posted by in categories: mathematics, physics, space travel

Tailoring and manipulating electromagnetic wave propagation has been of great interest within the scientific community for many decades. In this context, wave propagation has been engineered by properly introducing spatial inhomogeneities along the path where the wave is traveling. Antennas and communications systems in general have greatly benefited from this wave-matter control. For instance, if one needs to re-direct the radiated field (information) from an antenna (transmitter) to a desired direction and reach a receiving antenna placed at a different location, one can simply place the former in a translation stage and mechanically steer the propagation of the emitted electromagnetic wave.

Such beam steering techniques have greatly contributed to the spatial aiming of targets in applications such as radars and point-to-point communication systems. Beam steering can also be achieved using metamaterials and metasurfaces by means of spatially controlling the effective electromagnetic parameters of a designed meta-lens antenna system and/or using reconfigurable meta-surfaces. The next question to ask: Could we push the limits of current beam steering applications by controlling electromagnetic properties of media not only in space but also in time (i.e., 4D metamaterials x, y,z, t)? In order words, would it be possible to achieve temporal aiming of electromagnetic waves?

In a new paper published in Light Science & Applications, Victor Pacheco-Peña from the School of Mathematics, Statistics and Physics of Newcastle University in UK and Nader Engheta from and Department of Electrical and Systems Engineering of the University of Pennsylvania, USA have answered this question by proposing the idea of temporal metamaterials that change from an isotropic to an anisotropic permittivity tensor. In this concept, the authors consider a rapid change of the permittivity of the whole medium where the wave is traveling and demonstrated both numerically and analytically the effects of such a temporal boundary caused by the rapid temporal change of permittivity. In so doing, forward and backward waves are produced with wave vector k preserved through the whole process while frequency is changed, depending on the values of the permittivity tensor before and after the temporal change of permittivity.

Jul 21, 2020

Quantum Computing: Looking Ahead To Endless Possibilities

Posted by in categories: quantum physics, robotics/AI, space

However, to dismiss the subject as fantastical or unnecessary would be akin to telling scientists 100 years ago that landing on the moon was also irrelevant.

This is because, for pioneers and champions of artificial intelligence, quantum computing is the holy grail. It’s not a make-believe fantasy; rather, it’s a tangible area of science that will take our probability-driven world into a whole new dimension.

Jul 21, 2020

New cosmic magnetic field structures discovered in galaxy NGC 4217

Posted by in category: cosmology

Spiral galaxies such as our Milky Way can have sprawling magnetic fields. There are various theories about their formation, but so far the process is not well understood. An international research team has now analyzed the magnetic field of the Milky Way-like galaxy NGC 4217 in detail on the basis of radio astronomical observations and has discovered as yet unknown magnetic field structures. The data suggest that star formation and star explosions, so-called supernovae, are responsible for the visible structures.

The team led by Dr. Yelena Stein from Ruhr-Universität Bochum, the Centre de Données astronomiques de Strasbourg and the Max Planck Institute for Radio Astronomy in Bonn together with US-American and Canadian colleagues, published their report in the journal Astronomy and Astrophysics, released online on 21 July 2020.

The analyzed data had been compiled in the project “Continuum Halos in Nearby Galaxies”, where were utilized to measure 35 galaxies. “Galaxy NGC 4217 is of particular interest to us,” explains Yelena Stein, who began the study at the Chair of Astronomy at Ruhr-Universität Bochum under Professor Ralf-Jürgen Dettmar and who currently works at the Centre de Données astronomiques de Strasbourg. NGC 4217 is similar to the Milky Way and is only about 67 million light years away, which means relatively close to it, in the Ursa Major constellation. The researchers therefore hope to successfully transfer some of their findings to our home galaxy.

Jul 21, 2020

New Blood Test Detects 5 Types of Cancer Years Before Standard Diagnosis

Posted by in categories: bioengineering, biotech/medical

A blood test has been shown to detect five types of cancer years before the diseases could be spotted using conventional diagnostic methods, according to a study published Tuesday.

Developed by a Sino-US startup, the test found cancers in 91 percent of people who showed no symptoms when the blood sample was collected but were diagnosed one-to-four years later with stomach, esophageal, colon, lung or liver cancer, researchers reported in Nature Communications.

“The immediate focus is to test people at higher risk, based on family history, age or other known risk factors,” said co-author Kun Zhang, head of the bioengineering department at the University of California San Diego and an equity holder in Singlera Genomics, which developed the test.

Jul 21, 2020

Artificial Intelligence Is the Hope 2020 Needs

Posted by in categories: biotech/medical, internet, robotics/AI

The core of GPT-3, which is a creation of OpenAI, an artificial intelligence company based in San Francisco, is a general language model designed to perform autofill. It is trained on uncategorized internet writings, and basically guesses what text ought to come next from any starting point. That may sound unglamorous, but a language model built for guessing with 175 billion parameters — 10 times more than previous competitors — is surprisingly powerful.


With attention focused on a pandemic and an election, AI has taken a major leap forward.

Jul 21, 2020

How Harvard’s Star Computer-Science Professor Built a Distance-Learning Empire

Posted by in categories: biotech/medical, computing, education, science

David Malan, of the hit class CS50, was working to perfect online teaching long before the pandemic. Is his method a model for the future of higher education?

Jul 21, 2020

Scientists prove DNA can be reprogrammed by Words and Frequencies

Posted by in categories: biotech/medical, computing, genetics, internet

Amazing.


The human DNA is a biological internet and superior in many aspects to the artificial one. Russian scientific research directly or indirectly explains phenomena such as clairvoyance, intuition, spontaneous and remote acts of healing, self healing, affirmation techniques, unusual light/auras around people (namely spiritual masters), mind’s influence on weather patterns and much more. In addition, there is evidence for a whole new type of medicine in which DNA can be influenced and reprogrammed by words and frequencies WITHOUT cutting out and replacing single genes.

Only 10% of our DNA is being used for building proteins. It is this subset of DNA that is of interest to western researchers and is being examined and categorized. The other 90% are considered “junk DNA.” The Russian researchers, however, convinced that nature was not dumb, joined linguists and geneticists in a venture to explore those 90% of “junk DNA.” Their results, findings and conclusions are simply revolutionary!

Continue reading “Scientists prove DNA can be reprogrammed by Words and Frequencies” »

Jul 21, 2020

Tesla and SpaceX are partnering up to create new materials to use on Earth and in space

Posted by in categories: cyborgs, Elon Musk, space travel, sustainability

Elon Musk confirmed that Tesla plans to use a different alloy for the upcoming Cybertruck electric pickup.

When Tesla unveiled the Cybertruck last year, one of the most interesting features was the fact the vehicle isn’t going to be built using a traditional automotive body system but with an exoskeleton.

The automaker wrote about the exoskeleton:

Jul 21, 2020

Brain meta-state transitions demarcate thoughts across task contexts exposing the mental noise of trait neuroticism

Posted by in categories: entertainment, neuroscience

Explicit self-reflection is unreliable for measuring thoughts. Here, the authors use brain data to implicitly pinpoint transitions between thoughts and find thought turnover to be reliably predicted by narrative events during movie-viewing, as well as by greater trait neuroticism at rest.

Jul 21, 2020

Generative Feedback Explains Distinct Brain Activity Codes for Seen and Mental Images

Posted by in category: space

The relationship between mental imagery and vision is a long-standing problem in neuroscience. Currently, it is not known whether differences between the activity evoked during vision and reinstated during imagery reflect different codes for seen and mental images. To address this problem, we modeled mental imagery in the human brain as feedback in a hierarchical generative network. Such networks synthesize images by feeding abstract representations from higher to lower levels of the network hierarchy. When higher processing levels are less sensitive to stimulus variation than lower processing levels, as in the human brain, activity in low-level visual areas should encode variation in mental images with less precision than seen images. To test this prediction, we conducted an fMRI experiment in which subjects imagined and then viewed hundreds of spatially varying naturalistic stimuli. To analyze these data, we developed imagery-encoding models. These models accurately predicted brain responses to imagined stimuli and enabled accurate decoding of their position and content. They also allowed us to compare, for every voxel, tuning to seen and imagined spatial frequencies, as well as the location and size of receptive fields in visual and imagined space. We confirmed our prediction, showing that, in low-level visual areas, imagined spatial frequencies in individual voxels are reduced relative to seen spatial frequencies and that receptive fields in imagined space are larger than in visual space. These findings reveal distinct codes for seen and mental images and link mental imagery to the computational abilities of generative networks.

Keywords: encoding models; fMRI; generative network; mental imagery; receptive fields; vision.

Copyright © 2020 Elsevier Inc. All rights reserved.