To stay up to date you can also follow on Mastodon.

🔗 Technology 🔗 Physics 🔗 Telecommunications 🔗 Radio 🔗 Electronics 🔗 Engineering

In antenna theory, a phased array usually means an electronically scanned array, a computer-controlled array of antennas which creates a beam of radio waves that can be electronically steered to point in different directions without moving the antennas. The general theory of an electromagnetic phased array also finds applications in ultrasonic and medical imaging application (phased array ultrasonics) and in optics optical phased array.

In a simple array antenna, the radio frequency current from the transmitter is fed to multiple individual antenna elements with the proper phase relationship so that the radio waves from the separate elements combine (superpose) to form beams, to increase power radiated in desired directions and suppress radiation in undesired directions. In a phased array, the power from the transmitter is fed to the radiating elements through devices called phase shifters, controlled by a computer system, which can alter the phase or signal delay electronically, thus steering the beam of radio waves to a different direction. Since the size of an antenna array must extend many wavelengths to achieve the high gain needed for narrow beamwidth, phased arrays are mainly practical at the high frequency end of the radio spectrum, in the UHF and microwave bands, in which the operating wavelengths are conveniently small.

Phased arrays were originally conceived for use in military radar systems, to steer a beam of radio waves quickly across the sky to detect planes and missiles. These systems are now widely used and have spread to civilian applications such as 5G MIMO for cell phones. The phased array principle is also used in acoustics, and phased arrays of acoustic transducers are used in medical ultrasound imaging scanners (phased array ultrasonics), oil and gas prospecting (reflection seismology), and military sonar systems.

The term "phased array" is also used to a lesser extent for unsteered array antennas in which the phase of the feed power and thus the radiation pattern of the antenna array is fixed. For example, AM broadcast radio antennas consisting of multiple mast radiators fed so as to create a specific radiation pattern are also called "phased arrays".

🔗 Plants 🔗 Forestry 🔗 Ecology

Pioneer species are resilient species that are the first to colonize barren environments, or to repopulate disrupted biodiverse steady-state ecosystems as part of ecological succession. A number of kinds of events can create good conditions for pioneers, including disruption by natural disasters, such as wildfire, flood, mudslide, lava flow or a climate-related extinction event or by anthropogenic habitat destruction, such as through land clearance for agriculture or construction or industrial damage. Pioneer species play an important role in creating soil in primary succession, and stabilizing soil and nutrients in secondary succession.

For humans, because pioneer species quickly occupy disrupted spaces they are sometimes treated as weeds or nuisance wildlife, such as the common dandelion or stinging nettle. Even though humans have mixed relationships with these plants, these species tend to help improve the ecosystem because they can break up compacted soils and accumulate nutrients that help with a transition back to a more mature ecosystem. In human managed ecological restoration or agroforestry, trees and herbaceous pioneers can be used to restore soil qualities and provide shelter for slower growing or more demanding plants. Some systems use introduced species to restore the ecosystem, or for environmental remediation. The durability of pioneer species can also make them potential invasive species.

🔗 Gastropods

Micromelo undatus, common name the miniature melo, is an uncommon species of small sea snail or bubble snail, a marine opisthobranch gastropod mollusk in the family Aplustridae.

🔗 Mammals

Tuffi (born 1946, India – died 1989, Paris, France) was a female Asian elephant that became famous in West Germany during 1950 when she accidentally fell from the Wuppertal Schwebebahn into the River Wupper underneath.

On 21 July 1950, the circus director Franz Althoff (de) had Tuffi, then four years old, traveled on the suspended monorail in Wuppertal, as a publicity stunt. The elephant trumpeted wildly and ran through the carriage, broke through a window and fell 12 metres (39 ft) down into the River Wupper, suffering only minor injuries. A panic had broken out in the carriage and some passengers were injured. Althoff helped the elephant out of the water. Both the circus director and the official who had allowed the ride were fined. Tuffi was sold to Cirque Alexis Gruss (fr) in 1968; she died there in 1989.

No photograph of the incident is known; a widely circulated postcard picture is a montage. A building near the location of the incident, between the stations Alter Markt and Adlerbrücke, features a painting of Tuffi. A local milk-factory has chosen the name as a brand.

The Wuppertal tourist information keeps an assortment of Tuffi-related souvenirs, local websites show original pictures.

In 1970 Marguerita Eckel and Ernst-Andreas Ziegler published a children's picture book about the incident titled Tuffi und die Schwebebahn (“Tuffi and the suspension railway”).

🔗 Birds

Wrens are a family, Troglodytidae, of small brown passerine birds. The family includes 96 species and is divided into 19 genera. All species are restricted to the New World except for the Eurasian wren that is widely distributed in the Old World. In Anglophone regions, the Eurasian wren is commonly known simply as the "wren", as it is the originator of the name. The name wren has been applied to other, unrelated birds, particularly the New Zealand wrens (Acanthisittidae) and the Australian wrens (Maluridae).

Most wrens are visually inconspicuous though they have loud and often complex songs. Exceptions include the relatively large members of the genus Campylorhynchus, which can be quite bold in their behaviour. Wrens have short wings that are barred in most species, and they often hold their tails upright. Wrens are primarily insectivorous, eating insects, spiders and other small invertebrates, but many species also eat vegetable matter and some eat small frogs and lizards.

🔗 Philosophy 🔗 Politics 🔗 Psychology 🔗 Philosophy/Social and political philosophy 🔗 Sociology

A purity spiral is a theory which argues for the existence of a form of groupthink in which it becomes more beneficial to hold certain views than to not hold them, and more extreme views are rewarded while expressing doubt, nuance, or moderation is punished (a process sometimes called "moral outbidding"). It is argued that this feedback loop leads to members competing to demonstrate the zealotry or purity of their views.

A purity spiral is argued to occur when a community's primary focus becomes implementing a single value that has no upper limit, and where that value does not have an agreed interpretation.

🔗 LGBTQ+ studies

“Ur-Fascism” or “Eternal Fascism: Fourteen Ways of Looking at a Blackshirt” (in Italian: Il fascismo eterno, or Ur-Fascismo) is a renowned essay authored by the Italian philosopher, novelist, and semiotician Umberto Eco. First published in 1995, this influential essay provides an analysis of fascism, a definition of fascism, and discusses the fundamental characteristics and traits of fascism. Drawing on Eco's personal experiences growing up in Mussolini's Italy and his extensive research on fascist movements, the essay offers his insights into the nature of fascism and its manifestations.

🔗 Chemicals

Solanine is a glycoalkaloid poison found in species of the nightshade family within the genus Solanum, such as the potato (Solanum tuberosum), the tomato (Solanum lycopersicum), and the eggplant (Solanum melongena). It can occur naturally in any part of the plant, including the leaves, fruit, and tubers. Solanine has pesticidal properties, and it is one of the plant's natural defenses. Solanine was first isolated in 1820 from the berries of the European black nightshade (Solanum nigrum), after which it was named. It belongs to the chemical family of saponins.

🔗 Mathematics

In recreational mathematics, an almost integer (or near-integer) is any number that is not an integer but is very close to one. Almost integers may be considered interesting when they arise in some context in which they are unexpected.

🔗 Norway 🔗 Paranormal

The Hessdalen lights are unidentified lights which have been observed in a 12-kilometre-long (7.5 mi) stretch of the Hessdalen valley in rural central Norway periodically since at least the 1930s.