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75,186,104 | https://en.wikipedia.org/wiki/Cavorite | Cavorite is a fictional material first depicted by H. G. Wells in The First Men in the Moon, a 1901 scientific romance. Developed by Cavor, a reclusive physicist, it has the ability to negate the force of gravity, enabling him and a businessman named Bedford to travel to the Moon using a spherical spacecraft propelled by Cavorite blinds. The material was later referenced in numerous works of science fiction media, and its theoretical implications have been discussed by critics.
Creation
Into Other Worlds posits that Cavorite was based on a combination of lunarium, a fictional metal from A Voyage to the Moon (1827) by George Tucker, and apergy, from Across the Zodiac (1880) by Percy Greg, and that since Wells was unconcerned about the process of traveling to the Moon, he "borrowed freely from his predecessors".
Critical analysis
Beyond Reason states that a material such as Cavorite is impossible in the real world, as it contradicts the laws of conservation of energy. It would allow for the instant invention of a perpetual motion machine, such as a bicycle whose wheel, partly shielded from gravity, would spin at a faster and faster pace until it reached its mechanical limits.
Natural Space in Literature calls Cavorite a "rather fantastic" invention, saying that it was only slightly more scientific than the cannon shot in Jules Verne's From the Earth to the Moon (1865), but noting that the story itself focused more on realism than Verne's did. The book describes Cavorite as a convenient plot device that turned the reader's attention to "human questions" as soon as possible, comparing it to the shield of Achilles. It notes that while critics demanded realism in science fiction, Wells created a self-consistent story within the reality he created. In contrast, Sense of Wonder: A Century of Science Fiction called Cavorite "much more fanciful" than Verne's Columbiad cannon.
The Intellectuals and the Masses hypothesizes that the disaster almost caused by Cavorite destroying the atmosphere was representative of Wells' anxiety due to overpopulation and the ecological damage it caused, due to his childhood experiences.
References
Fictional materials
H. G. Wells | Cavorite | [
"Physics"
] | 454 | [
"Materials",
"Fictional materials",
"Matter"
] |
75,187,598 | https://en.wikipedia.org/wiki/Homosexual%20behavior%20in%20sheep | Homosexual behavior in sheep has been well documented and studied. The domestic sheep (Ovis aries) is the only species of mammal except for humans which exhibits exclusive homosexual behavior. "About 10% of rams (males) refuse to mate with ewes (females) but do readily mate with other rams." Thirty percent of all rams demonstrate at least some homosexual behavior. One report on sheep found that 8% of rams exhibited homosexual preferences—that is, even when given a choice, they chose male over female partners.
This documented homosexual preference has garnered much discussion. Such rams prefer to court and mount other rams only, even in the presence of estrous ewes. Moreover, around 18–22% of rams are bisexual.
Several observations indicate that male–male sexual preference in rams is sexually motivated. Rams routinely perform the same courtship behaviors (including foreleg kicks, nudges, vocalizations, anogenital sniffs and flehmen) prior to mounting other males as observed when other rams court and mount estrous females. Furthermore, pelvic thrusting and ejaculation often accompany same-sex mounts by rams. The Merck Manual of Veterinary Medicine lists homosexuality as a "normal behavior" in up to 30% of all rams in its section on behavioral problems. Additionally, a small number of females that were accompanied by a male fetus in utero (i.e. as fraternal twins) are freemartins (female animals with intersex characteristics like being behaviorally masculine and lacking functioning ovaries).
Biological causes
A number of studies have reported differences in brain structure and function between male-oriented and female-oriented rams, suggesting that sexual partner preferences are neurologically hard-wired. Long-term studies of homosexual behavior in domesticated sheep led by Charles Roselli have found that 6-8% of rams have a homosexual preference through their life. Dissection of ram brains also found a similar smaller (feminized) structure in homosexually oriented rams compared to heterosexually oriented rams in the equivalent brain region to the human sexually dimorphic nucleus (SDN), the ovine sexually dimorphic nucleus (oSDN).
The size of the sheep oSDN has also been demonstrated to be formed in utero, rather than postnatally, underscoring the role of prenatal hormones in masculinization of the brain for sexual attraction. Their 2003 study at Oregon Health and Science University stated that homosexuality in male sheep is associated with a region in the rams' brains which the authors call the "ovine Sexually Dimorphic Nucleus" (oSDN) which is half the size of the corresponding region in heterosexual male sheep. Scientists found that, "The oSDN in rams that preferred females was significantly larger and contained more neurons than in male-oriented rams and ewes. In addition, the oSDN of the female-oriented rams expressed higher levels of aromatase, a substance that converts testosterone to estradiol, a form of estrogen which is believed to facilitate typical male sexual behaviors.
Aromatase expression was no different between male-oriented rams and ewes [...] The dense cluster of neurons that comprise the oSDN express cytochrome P450 aromatase. Aromatase mRNA levels in the oSDN were significantly greater in female-oriented rams than in ewes, whereas male-oriented rams exhibited intermediate levels of expression." These results suggest that "... naturally occurring variations in sexual partner preferences may be related to differences in brain anatomy and its capacity for estrogen synthesis." As noted before, given the potential unaggressiveness of the male population in question, the differing aromatase levels may also have been evidence of aggression levels, not sexuality. It should also be noted that the results of this particular study have not been confirmed by other studies.
Sheep are one of the few animals where the molecular basis of the diversity of male sexual preferences has been examined. However, this research has been controversial, and much publicity has been produced by a study at the Oregon Health and Science University that investigated the mechanisms that produce homosexuality in rams. Organizations such as PETA campaigned against the study, accusing scientists of trying to cure homosexuality in the sheep. OHSU and the involved scientists vehemently denied such accusations.
Research on potential social factors
Studies have failed to identify any compelling social factors that can predict or explain the variations in sexual partner preferences of domestic rams. Homosexual orientation and same-sex mounting in rams is not related to dominance, social rank or competitive ability. Indeed, male-oriented rams are not more or less dominant than female-oriented rams. Homosexual orientation in rams is also not affected by rearing conditions, i.e., rearing males in all-male groups, rearing male and female lambs together, early exposure of adolescent males to females and early social experiences with females do not promote or prevent homosexual orientation in rams. Male-oriented partner preference also does not appear to be an artifact caused by captivity or human management of sheep.
Homosexual behavior in related species
Homosexual courtship and sexual activity routinely occur among rams of wild sheep species, such as bighorn sheep (Ovis canadensis), thinhorn sheep (Ovis dalli), mouflons and urials (Ovis orientalis). Usually a higher ranking older male courts a younger male using a sequence of stylized movements. To initiate homosexual courtship, a courting male approaches the other male with his head and neck lowered and extended far forward in what is called the 'low-stretch' posture. He may combine this with the 'twist,' in which the courting male sharply rotates his head and points his muzzle toward the other male, often while flicking his tongue and making grumbling sounds. The courting male also often performs a 'foreleg kick', in which he snaps his front leg up against the other male's belly or between his hind legs. He also occasionally sniffs and nuzzles the other male's genital area and may perform the flehmen response. Thinhorn rams additionally lick the penis of the male they are courting. In response, the male being courted may rub his cheeks and forehead on the courting male's face, nibble and lick him, rub his horns on the courting male's neck, chest, or shoulders, and develop an erection. Males of another wild sheep species, the Asiatic mouflons, perform similar courtship behaviors towards fellow males.
Sexual activity between wild males typically involves mounting and anal intercourse. In Thinhorn sheep, genital licking also occurs. During mounting, the larger male usually mounts the smaller male by rearing up on his hind legs and placing his front legs on his partner's flanks. The mounting male usually has an erect penis and accomplishes full anal penetration while performing pelvic thrusts that may lead to ejaculation. The mounted male arches his back to facilitate the copulation. Homosexual courtship and sexual activity can also take place in groups composed of three to ten wild rams clustered together in a circle. These non-aggressive groups are called 'huddles' and involve rams rubbing, licking, nuzzling, horning, and mounting each other. Female Mountain sheep also engage in occasional courtship activities with one another and in sexual activities such as licking each other's genitals and mounting.
See also
References
Sexual orientation and science
Ethology
Animal sexuality
Homosexuality
LGBTQ studies | Homosexual behavior in sheep | [
"Biology"
] | 1,518 | [
"Behavior",
"Animals",
"Behavioural sciences",
"Animal sexuality",
"Ethology",
"Sexuality"
] |
75,187,709 | https://en.wikipedia.org/wiki/Cagrilintide | Cagrilintide is a long-acting analogue of amylin. It is being tested to treat obesity and type 2 diabetes by itself and in combination with semaglutide as cagrilintide/semaglutide.
Research
A systematic review and metanalysis of cagrisema, published in 2024, found that cagrisema may provide weight loss benefits.
References
Amylin receptor agonists
Experimental diabetes drugs
Cyclic peptides | Cagrilintide | [
"Chemistry"
] | 96 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
75,187,722 | https://en.wikipedia.org/wiki/Cagrilintide/semaglutide | Cagrilintide/semaglutide, marketed as CagriSema, is a combination of cagrilintide, a dual amylin and calcitonin receptor agonist, and semaglutide, a GLP-1 agonist. It is injected once weekly and is being tested in type 2 diabetes and obesity. Preliminary trial results found a greater weight loss compared to either medication alone. HbA1c was significantly improved compared to cagrilintide alone and non-significantly better than semaglutide alone. In a Phase II trial, weight loss averaged -15.6 percent after 32 weeks, making CagriSema comparable in efficacy to tirzepatide. A future trial sponsored by Novo Nordisk is comparing tirzepatide and CagriSema head-to-head.
CagriSema entered Phase III clinical trials in 2023. In December 2024, Novo Nordisk announced the results of REDEFINE 1, one of their series of Phase III trials, testing weekly cagrilintide 2.4 mg and semaglutide 2.4 mg individually and together versus placebo in obese or overweight subjects with one or more comorbidities. In the intention-to-treat analysis, people treated with CagriSema lost 20.4% of their body weight over 68 weeks, versus 11.5% with cagrilintide 2.4 mg alone, 14.9% with semaglutide 2.4 mg alone, and 3.0% with placebo.
References
GLP-1 receptor agonists
Experimental diabetes drugs
Peptide therapeutics
Amylin receptor agonists
Combination diabetes drugs
Combination anti-obesity drugs | Cagrilintide/semaglutide | [
"Chemistry"
] | 358 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
70,881,880 | https://en.wikipedia.org/wiki/Elizabeth%20A.%20Fulton | Elizabeth A. Fulton (born 1973), also known as Beth Fulton, is an Australian ecosystem modeller, who was elected a Fellow of the Australian Academy of Science in 2022. She is a Research Group Leader at CSIRO Oceans & Atmosphere in Hobart, Tasmania.
Career
Fulton was born in 1973 on a farm near Goulburn, NSW, and expressed a keen interest in maths as well a curiosity about the natural environment. Fulton was awarded her BSc in Mathematics and Marine Biology from James Cook University (1997), and her PhD from the University of Tasmania in 2000. Her thesis was titled ‘The effects of the structure and formulation of ecosystem models on model performance’.
Fulton started working at CSIRO in 2001, investigating indicators of the ecological effects of fishing. She developed the model Atlantis, and was appointed a research scientist in 2004. The Atlantis model was evaluated to be the 'world's best for evaluation of marine fisheries by the United Nations Food and Agriculture Organisation, and was utilised to provide advice on fisheries within the United States, Europe and Australia. She also worked on the model InVitro, which explores the impacts and managements of different pressures on coastal and marine environments. The models give equal weighting to both human and biophysical components within marine ecosystems. Fulton has described the process of building complex models as follows: "We need to talk to the people who’ve spent their lives studying the different bits of the system – currents, climate, plankton, fish, sharks, whales, fisherman, local shop keepers, managers, the whole kit and kaboodle. We spend months getting the thing going and making sure it works like the real thing, we try to make it as accurate as possible."
Media
Fulton has published her marine biology work in The Conversation, on extreme weather impacts due to climate change, on exploring the future with models, on how Australia could be self-sufficient, warming oceans changing the fishing industry, as well as damage to Australia's coasts, from extreme weather.
Publications
Lessons in modelling and management of marine ecosystems: the Atlantis experience (2011). EA Fulton, JS Link, IC Kaplan, M Savina‐Rolland, P Johnson, et al. Fish and fisheries 12 (2), 171–188. doi.org/10.1111/j.1467-2979.2011.00412.x
Next-generation ensemble projections reveal higher climate risks for marine ecosystems (2021) DP Tittensor, C Novaglio, CS Harrison, RF Heneghan, N Barrier, et al. Nature climate change 11 (11), 973–981.doi.org/10.1038/s41558-021-01173-9
Rebuilding global fisheries (2009) B Worm, R Hilborn, JK Baum, TA Branch, JS Collie, C Costello, ...Science 325 (5940), 578–585. DOI: 10.1126/science.1173146.
Awards
2022 - Fellow of the Australian Academy of Science
2022 - Fellow of the Australian Academy of Technological Sciences and Engineering
2020 - Beverton Medal distinguished scientist for a lifelong contribution to fisheries science - Fisheries Society of the British Isles
2019 - K. Radway Allen Award for outstanding contribution in fish or fisheries science - Australian Society for Fish Biology
2017-2020 - Highly Cited Researcher in Plant & Animal Science - Clarivate Analytics
2017 - Biennial medallist - Modelling and Simulation Society of Australia and New Zealand* 2016 - Hall of Fame Australian Society For Fish Biology
2011 - Sustainability Science Award - ESA
2010 - Pew Marine Science Fellowship - Pew
2007 - Science Minister's Prize for Life Scientist of the Year, Australian Prime Minister's Science Prizes
2004 - Award for outstanding PhD, Royal Society of Tasmania
References
External links
CSIRO homepage
AFSB awards
Thesis at University of Tasmania
Ecologists
Australian women scientists
Women marine biologists
Australian women academics
Australian marine biologists
CSIRO people
Living people
1973 births
Fellows of the Australian Academy of Science
Fellows of the Australian Academy of Technological Sciences and Engineering | Elizabeth A. Fulton | [
"Environmental_science"
] | 831 | [
"Ecologists",
"Environmental scientists"
] |
70,883,326 | https://en.wikipedia.org/wiki/Opegrapha%20verseghyklarae | Opegrapha verseghyklarae is a little-known species of lichenicolous (lichen-eating) fungus in the family Opegraphaceae. It is found in the Russian Far East, where it grows on the thalli and apothecia of the crustose lichen Ochrolechia pallescens.
Taxonomy
Opegrapha verseghyklarae was formally described as a new species in 2015 by lichenologists Sergey Kondratyuk, Laszlo Lőkös, and Jae-Seoun Hur. The type specimen was collected from the Land of the Leopard National Park in the Primorsky Krai region of the Russian Far East. There, in a deciduous forest in the Kedrovaya Pad Nature Reserve, the fungus was found growing on the thallus and apothecia of Ochrolechia pallescens, which itself was growing in close association with Ivanpisutia oxneri and species of Catillaria. The species epithet verseghyklarae honours Hungarian lichenologist Klára Verseghy, who, according to the authors, "made important contributions to our knowledge on species diversity of the genus Ochrolechia".
Description
Opegrapha verseghyklarae produces black, rounded ascomata that are up to 0.25 mm in diameter. The ascomata are often empty, or lacking a hymenium. The asci are somewhat club-shaped (subclavate), contain eight spores. These ascospores are hyaline, have three transverse septa and are shaped like an elongated ellipsoid, with dimensions of 13–15 by 5–6 μm. Older spores become brownish from a pigment on the spore wall, and become covered with wart-like growths (verrucae).
Opegrapha anomea is morphologically similar to O. verseghyklarae, but that species has lirellate (not rounded) ascomata, has larger ascospores (17–26 by 6.5–9 μm), and its hosts are both species of Ochrolechia and of Pertusaria.
Habitat and distribution
The fungus is known only from a couple of locations in the Primorsky Krai region of the Russian Far East. Ochrolechia pallescens is the only known host lichen.
Opegrapha verseghyklarae is one of three Opegrapha species known to parasitise members of the genus Ochrolechia; the others are Opegrapha blakii and Opegrapha anomea.
References
Opegraphaceae
Lichenicolous fungi
Fungi described in 2015
Fungi of Asia
Taxa named by Sergey Kondratyuk
Taxa named by Jae-Seoun Hur
Taxa named by László Sándor Lőkös
Fungus species | Opegrapha verseghyklarae | [
"Biology"
] | 588 | [
"Fungi",
"Fungus species"
] |
70,884,169 | https://en.wikipedia.org/wiki/StatMuse | StatMuse Inc. is an American artificial intelligence company founded in 2014. The company maintains its own eponymous website where it hosts a database of sports statistics.
History
Friends Adam Elmore and Eli Dawson founded the company in 2014. In email correspondence to the Springfield News-Leader, Elmore detailed that he and Dawson, fans of the National Basketball Association (NBA), were compelled to create StatMuse after they realized there was not a place online they could search "lebron james most points" [sic] and quickly get a result "showing his highest scoring games." As a startup, the company's goal was to utilize a type of artificial intelligence called natural language processing (NLP) for sports.
In 2015, the company was part of the second group of startups accepted into the Disney Accelerator program. The company ultimately received the backing of The Walt Disney Company, Techstars, Allen & Company, the NFL Players Association, Greycroft and NBA Commissioner David Stern. As part of their partnership with Disney, StatMuse signed a content deal with ESPN (owned by Disney) to provide stats content on social media and television during the 2015–16 NBA season.
Initially, the company only had stats available for the NBA, but eventually expanded to provide stats for the other major North American sports leagues. The company's initial demographic was players of fantasy sports, but eventually expanded to target general sports fans as well. StatMuse offers responses to user queries in the voices of sports-related public figures. Dawson shared with VentureBeat that StatMuse brings people in and record them saying different words and phrases. These celebrity voices were made accessible through Google's Google Assistant service, Microsoft's Cortana virtual assistant, and Amazon's Echo devices.
The company launched its phone app in September 2017. Through the app, users can query StatMuse's sports statistics database using their own natural language. Upon the launch of the phone app, Fitz Tepper of TechCrunch wrote that: "The technology isn't perfect – some of the pauses between words are a bit awkward – making it clear that some phrases is being stitched together on the fly. But this is the exception, and on the whole most responses sound pretty good." StatMuse plug-ins for Slack and Facebook Messenger were also made, providing text-based sports stats. In 2019, StatMuse received investment from the Google Assistant Investment program.
The service launched a premium option dubbed StatMuse+ in May 2023, offering options that had previously been included for free, such as unlimited searches and full results in data tables. The premium version also included early access to new features and a personalized searched history, as well as not having ads. It was met with mixed feedback.
In January 2024, the service launched a Premier League version of the website dubbed StatMuse FC. It is planned to introduce more leagues in the website.
References
2014 establishments in California
American companies established in 2014
American sport websites
Analytics companies
Chatbots
Companies based in San Francisco
Data companies
Internet properties established in 2014
Natural language processing
Online companies of the United States
Sports records and statistics | StatMuse | [
"Technology"
] | 638 | [
"Natural language processing",
"Natural language and computing"
] |
70,884,973 | https://en.wikipedia.org/wiki/FatFs | FatFs is a lightweight software library for microcontrollers and embedded systems that implements FAT/exFAT file system support. Written on pure ANSI C, FatFs is platform-independent and easy to port on many hardware platforms such as 8051, PIC, AVR, ARM, Z80. FatFs is designed as thread-safe and is built into ChibiOS, RT-Thread, ErlendOS, and Zephyr real-time operating systems.
Most often, FatFs is used in low-power Embedded systems where memory is limited, since the library takes up little space in RAM and program code. In the minimum version, the working code takes from 2 to 10 kB of RAM.
Overview
FatFs is designed to be a Filesystem Layer that is agnostic to the platform and storage media it is used with. This is achieved by providing a media access interface that is used to communicate with the storage device control module which is provided by the implementer. This means that FatFs can work with any physical device such as an SD card or a hard disk on any platform that can run plain C code if the implementer provides a control module interface.
Architecture
FatFs library architecture logically separates the abstractions of the user app and the platform-dependent code. The user application and the low level disk I/O layer (driver) must be added by the implementer. Also, the architecture of the library implies that the system can have several storage devices with different drivers and the library can work in a multi-threaded operating system. At the application level it is hidden which physical media is used.
In the minimum implementation, the driver layer must support at least these 3 interfaces:
disk_status — return block device status (not initialized, missing, protected, ready)
disk_initialize — initialize the physical disk
disk_read — read block from physical disk
This level of abstraction allows implementers to write an application once, and then port it on different platforms, changing only the implementation of the driver.
License
FatFs has its own minimalistic license similar to the BSD license. It allows usage in commercial products without disclosing the source code. The only condition is to keep the copyright notice in case of redistribution of the source code. The conditions of FatFs license do not cover any redistributions in binary form, such as embedded code and hex files.
Projects using FatFs
Arduino (STM32Duino) — port of Arduino platform for STM32 MCU's
ChibiOS/RT — open-source real-time operating system (RTOS) for microcontrollers
Flipper Zero — open source portable multi-tool device
Marlin (firmware) — open source firmware for 3D printers and CNC machines
ESP-IDF — official IoT Development Framework for the ESP32 series SoC's
Prusa Mini — open-source firmware for low cost 3D printer
RT-Thread — open-source real-time operating system for embedded systems
Zephyr — real-time operating system for embedded systems supporting multiple architectures
ErlendOS — an open source minimal UNIX-like operating system for embedded systems
EZ-Flash Omega - Family of flashcarts for the Nintendo Game Boy Advance.
References
Computer libraries
Microcontroller software | FatFs | [
"Technology"
] | 674 | [
"IT infrastructure",
"Computer libraries"
] |
70,885,165 | https://en.wikipedia.org/wiki/NGC%204731 | NGC 4731 is a barred spiral galaxy located near the Virgo Supercluster. To its celestial south lies NGC 4731A, a small irregular galaxy. Both galaxies feature high concentrations of neutral HI gas. It is theorized that its elongated arm structure could be related to gravitational interactions with a nearby galaxy, NGC 4967. It is a member of the NGC 4697 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.
Gallery
See also
New General Catalogue
References
4731
Virgo (constellation)
Barred spiral galaxies
Virgo Supercluster | NGC 4731 | [
"Astronomy"
] | 140 | [
"Virgo (constellation)",
"Constellations"
] |
70,885,459 | https://en.wikipedia.org/wiki/PhyCV | PhyCV is the first computer vision library which utilizes algorithms directly derived from the equations of physics governing physical phenomena. The algorithms appearing in the first release emulate the propagation of light through a physical medium with natural and engineered diffractive properties followed by coherent detection. Unlike traditional algorithms that are a sequence of hand-crafted empirical rules, physics-inspired algorithms leverage physical laws of nature as blueprints. In addition, these algorithms can, in principle, be implemented in real physical devices for fast and efficient computation in the form of analog computing. Currently PhyCV has three algorithms, Phase-Stretch Transform (PST) and Phase-Stretch Adaptive Gradient-Field Extractor (PAGE), and Vision Enhancement via Virtual diffraction and coherent Detection (VEViD). All algorithms have CPU and GPU versions. PhyCV is now available on GitHub and can be installed from pip.
History
Algorithms in PhyCV are inspired by the physics of the photonic time stretch (a hardware technique for ultrafast and single-shot data acquisition). PST is an edge detection algorithm that was open-sourced in 2016 and has 800+ stars and 200+ forks on GitHub. PAGE is a directional edge detection algorithm that was open-sourced in February, 2022. PhyCV was originally developed and open-sourced by Jalali-Lab @ UCLA in May 2022. In the initial release of PhyCV, the original open-sourced code of PST and PAGE is significantly refactored and improved to be modular, more efficient, GPU-accelerated and object-oriented. VEViD is a low-light and color enhancement algorithm that was added to PhyCV in November 2022.
Background
Phase-Stretch Transform (PST)
Phase-Stretch Transform (PST) is a computationally efficient edge and texture detection algorithm with exceptional performance in visually impaired images. The algorithm transforms the image by emulating propagation of light through a device with engineered diffractive property followed by coherent detection. It has been applied in improving the resolution of MRI image, extracting blood vessels in retina images, dolphin identification, and waste water treatment, single molecule biological imaging, and classification of UAV using micro Doppler imaging.
Phase-Stretch Adaptive Gradient-Field Extractor (PAGE)
Phase-Stretch Adaptive Gradient-Field Extractor (PAGE) is a physics-inspired algorithm for detecting edges and their orientations in digital images at various scales. The algorithm is based on the diffraction equations of optics. Metaphorically speaking, PAGE emulates the physics of birefringent (orientation-dependent) diffractive propagation through a physical device with a specific diffractive structure. The propagation converts a real-valued image into a complex function. Related information is contained in the real and imaginary components of the output. The output represents the phase of the complex function.
Vision Enhancement via Virtual diffraction and coherent Detection (VEViD)
Vision Enhancement via Virtual diffraction and coherent Detection (VEViD) a efficient and interpretable low-light and color enhancement algorithm that reimagines a digital image as a spatially varying metaphoric light field and then subjects the field to the physical processes akin to diffraction and coherent detection. The term “Virtual” captures the deviation from the physical world. The light field is pixelated and the propagation imparts a phase with an arbitrary dependence on frequency which can be different from the quadratic behavior of physical diffraction. VEViD can be further accelerated through mathematical approximations that reduce the computation time without appreciable sacrifice in image quality. A closed-form approximation for VEViD which we call VEViD-lite can achieve up to 200 FPS for 4K video enhancement.
PhyCV on the Edge
Featuring low-dimensionality and high-efficiency, PhyCV is ideal for edge computing applications. In this section, we demonstrate running PhyCV on NVIDIA Jetson Nano in real-time.
NVIDIA Jetson Nano Developer Kit
NVIDIA Jetson Nano Developer Kit is a small- sized and power-efficient platform for edge computing applications. It is equipped with an NVIDIA Maxwell architecture GPU with 128 CUDA cores, a quad-core ARM Cortex-A57 CPU, 4GB 64-bit LPDDR4 RAM, and supports video encoding and decoding up to 4K resolution. Jetson Nano also offers a variety of interfaces for connectivity and expansion, making it ideal for a wide range of AI and IoT applications. In our setup, we connect a USB camera to the Jetson Nano to acquire videos and demonstrate using PhyCV to process the videos in real-time.
Real-time PhyCV on Jetson Nano
We use the Jetson Nano (4GB) with NVIDIA JetPack SDK version 4.6.1, which comes with pre- installed Python 3.6, CUDA 10.2, and OpenCV 4.1.1. We further install PyTorch 1.10 to enable the GPU accelerated PhyCV. We demonstrate the results and metrics of running PhyCV on Jetson Nano in real-time for edge detection and low-light enhancement tasks. For 480p videos, both operations achieve beyond 38 FPS, which is sufficient for most cameras that capture videos at 30 FPS. For 720p videos, PhyCV low-light enhancement can operate at 24 FPS and PhyCV edge detection can operate at 17 FPS.
Highlights
Modular Code Architecture
The code in PhyCV has a modular design which faithfully follows the physical process from which the algorithm was originated. Both PST and PAGE modules in the PhyCV library emulate the propagation of the input signal (original digital image) through a device with engineered diffractive property followed by coherent (phase) detection. The dispersive propagation applies a phase kernel to the frequency domain of the original image. This process has three steps in general, loading the image, initializing the kernel and applying the kernel. In the implementation of PhyCV, each algorithm is represented as a class in Python and each class has methods that simulate the steps described above. The modular code architecture follows the physics behind the algorithm. Please refer to the source code on GitHub for more details.
GPU Acceleration
PhyCV supports GPU acceleration. The GPU versions of PST and PAGE are built on PyTorch accelerated by the CUDA toolkit. The acceleration is beneficial for applying the algorithms in real-time image video processing and other deep learning tasks. The running time per frame of PhyCV algorithms on CPU (Intel i9-9900K) and GPU (NVIDIA TITAN RTX) for videos at different resolutions are shown below. Note that the PhyCV low-light enhancement operates in the HSV color space, so the running time also includes RGB to HSV conversion. However, for all running times using GPUs, we ignore the time of moving data from CPUs to GPUs and count the algorithm operation time only.
Installation and Examples
Please refer to the GitHub README file for a detailed technical documentation.
Current Limitations
I/O (Input/Output) Bottleneck for Real-time Video Processing
When dealing with real-time video streams from cameras, the frames are captured and buffered in CPU and have to be moved to GPU to run the GPU-accelerated PhyCV algorithms. This process is time-consuming and it is a common bottleneck for real-time video-processing algorithms.
Lack of Parameter Adaptivity for Different Images
Currently, the parameters of PhyCV algorithms have to be manually tuned for different images. Although a set of pre-selected parameters work relatively well for a wide range of images, the lack of parameter adaptivity for different images remains a limitation for now.
See also
Edge detection
Feature detection (computer vision)
Time stretch analog-to-digital converter
Time stretch dispersive Fourier transform
Phase stretch transform
References
Computer vision software
Computer vision | PhyCV | [
"Engineering"
] | 1,663 | [
"Artificial intelligence engineering",
"Packaging machinery",
"Computer vision"
] |
70,885,623 | https://en.wikipedia.org/wiki/Flipper%20Zero | The Flipper Zero is a portable multi-functional device developed for interaction with access control systems. The device is able to read, copy, and emulate RFID and NFC tags, radio remotes, iButtons, and digital access keys. It also has a GPIO interface. It was first announced in August 2020 through the Kickstarter crowdfunding campaign, which raised $4.8 million. The first devices were delivered to backers 18 months after completion of the crowdfunding campaign. The device's user interface embodies a pixel-art dolphin virtual pet. The interaction with the virtual pet is the device's core game mechanic. The usage of the device's functions defines the appearance and emotions of the pet.
In the built-in game, the main mechanism to "upgrade" the dolphin is to use the various hacking tools. While harmless uses (like as a remote control for a television, or carbon dioxide sensor) exist, some of the built-in tools have potential criminal uses, including RFID skimming, Bluetooth spamming (spamming a Bluetooth connection, crashing a person's phone), and emulation of RFID chips such as those found in identification badges, using the built-in radio cloner to open garage doors, unlocking cars, and functioning as a wireless BadUSB.
Origin
The device was developed by Alex Kulagin and Pavel Zhovner in 2019. They started raising funds on Kickstarter.
Overview
Flipper Zero is designed for interaction with various types of access control systems, radio protocols, RFID, near-field communication (NFC), and infrared signals. To operate the device, a computer or a smartphone is not required; it can be controlled via a 5-position D-pad and a separate back button. Flipper Zero has a monochrome orange backlight LCD screen with a resolution of 128× 64 pixels. For connection with external modules, the device has general-purpose input/output (GPIO) pinholes on the top side. User data and firmware updates are stored on a microSD card. Some actions, such as firmware or user data update, require a connection to a computer or a smartphone with the developer's software installed.
In July 2023, an app store was opened for the device.
Technical specification
The electronic schematics and firmware of the Flipper Zero project are open sourced under the GNU General Public License. At the same time, the device does not fit into the open-source hardware category because the printed circuit boards are not open-sourced, which does not allow enthusiasts to make their own copies of the device without knowledge of electrical engineering.
Hardware
Flipper Zero's hardware consists of four PCB modules connected by flexible cables. The battery is positioned in the center of the device between three of the PCBs.
Main PCB (motherboard)contains core components, including the main processor (STM32WB55), GPIO breakout pins, LCD display, Sub-GHz chip and its antenna, Bluetooth antenna, microSD card slot, battery controller, USB Type-C port, and membrane switches for the D-pad. All additional PCBs connect to the main PCB via flexible cables.
Infrared and iButton PCBa small board equipped with an infrared receiver (TSOP-75338) and three infrared LEDs for transmitting infrared signals. Includes three pogo pins for iButton (1-Wire) tags and a piezo buzzer (BCE-MX8530A) for audio feedback.
NFC PCBcontains the NFC chip (STM ST25R3916) along with analog circuitry for 125 kHz RFID.
Dual-Band RFID Antenna PCBfeatures two passive coil antennas: one for 13.56 MHz NFC communication and another for 125 kHz RFID systems.
Microcontroller (MCU)
Flipper Zero is based on a dual-core ARM architecture STM32WB55 microcontroller, which has 256 KB of RAM and 1 MB of Flash storage. The first core is a 64 MHz Cortex-M4 which runs the main firmware. The second core is a 32 MHz Cortex-M0 which runs STMicroelectronics proprietary firmware that implements the Bluetooth Low Energy protocol. Secret keys stored in the Secure Enclave of STM32WB55 are used to decrypt cryptographic keys on the fly, which are then applied to decode Sub-GHz protocols. This mechanism allows the device to handle encrypted communication for Sub-GHz protocols. However, the encryption used is not entirely secure and primarily serves as a form of obfuscation rather than robust protection. Its purpose is to make reverse engineering more challenging, but it does not provide absolute security.
Sub-GHz radio
For radio transmitting and receiving in the 300–900 MHz radio frequency range, a Texas Instruments CC1101 chip is used, which supports amplitude-shift keying (ASK) and frequency-shift keying (FSK) modulations. Unlike software-defined radio, the CC1101 chip cannot capture raw radio signals. This limitation requires the user to pre-configure the modulation parameters before receiving a radio signal, otherwise the signal will be received incorrectly.
Infrared
The infrared transceiver in Flipper Zero consists of a digital receiver and an LED circuit. The receiver, based on the TSOP-75338 module, decodes incoming infrared signals. Infrared transmission is managed by three LEDs directly connected to the MCU, which controls the signal output.
NFC and 125 kHz RFID
The NFC subsystem is based on the STM ST25R3916 chip, which is responsible for reading and emulating high-frequency cards. The 125 kHz low-frequency RFID functionality in Flipper Zero is implemented primarily through software running on the MCU, without a dedicated RFID chip. It also supports reading RFID tags in the 110–140 kHz range, albeit with a reduced reading distance.
Hardware expansion
In February 2024, a video game module was released for the Flipper Zero by its makers. The device allows the Flipper to be used as a game controller or connected to a TV and is based around the Raspberry Pi Pico.
Firmware
The Flipper Zero firmware is based on the FreeRTOS operating system, with its own software abstraction over the hardware layer. The firmware is mostly written in the C programming language, with occasional use of C++ in third-party modules. The system uses multitasking in combination with an event-driven architecture to organize the interaction of applications and services executed in a single address space and communicating through a system of queues and events. The system can be executed from both random-access memory (RAM) and read-only memory (ROM). Execution from RAM is used to deliver over-the-air (OTA) firmware updates.
The firmware consists of the following components:
FuriCore – provides an API for interaction with the scheduler and multithreading. FuriCore abstracts and extends the functionality of the FreeRTOS scheduler and adds additional system primitives.
FuriHal – provides an API for interaction with hardware.
Services and applications – the main functionality of the device. Sub-GHz, Infrared, RFID, NFC, etc are applications for user interaction. Graphical user interface (GUI), command-line interface (CLI), Notification, Storage, etc are additional APIs for applications development.
A set of libraries and drivers – covers various communication protocols, device drivers, file system drivers, and developer tools.
User and system data is stored in built-in flash memory, which is based on the LittleFS library. Interaction with the file system on the SD card is implemented using the FatFs library.
The build system is based on the SCons tool with additional tooling written in Python. For compilation, the system uses its own open toolchain based on GNU Compiler Collection.
Applications
Sub-GHz
Flipper Zero has a built-in module that can read, store, and emulate remote controls, allowing it to receive and send radio frequencies between 300 and 928 MHz. These switches, radio locks, wireless doorbells, remote controls, barriers, gates, smart lighting, and other devices can all be operated with these controls. Using Sub-GHz Flipper Zero can also receive and decode the data from many weather stations.
125 kHz RFID
Flipper Zero is compatible with low-frequency (LF) radio frequency identification (RFID), which is used in supply chain tracking systems, animal chips, and access control systems. LF RFID cards typically don't offer high levels of security, in contrast to NFC cards. Numerous form factors of this technology are available, including plastic cards, key fobs, tags, wristbands, and animal microchips. A low-frequency RFID module in the Flipper Zero can read, save, simulate, and write LF RFID cards.
NFC
NFC technology, which is used in smart cards for access control and cards, and digital business cards, is compatible with Flipper Zero. The 13.56 MHz NFC module has the ability to imitate, read, and store these cards. An NFC card is a transponder with a unique identification (UID), and rewritable memory for data storage. When placed close to a reader, NFC cards transmit the needed data.
Infrared
Flipper Zero can read and transmit signals that use infrared light (IR) such as TVs, air conditioners, or audio devices. It can learn and save infrared remote controls or use its own Universal remotes.
GPIO and modules
Flipper Zero explores hardware, flash firmware, debugging, and fuzz. It is able to function as a USB converter for UART, SPI, or I2C. The built-in GPIO pins connect to hardware, operate by buttons, send out code, and display messages on the LCD screen.
iButton
The Flipper Zero has an iButton connector to allow it to read and emulate iButton contact keys.
BadUSB
BadUSB devices have the ability to alter system settings, unlock backdoors, recover data, launch reverse shells, and do any other physical access-based actions. Flipper Zero can function as a BadUSB and, when connected to an insecure computing device, acts as a keyboard-like Human interface device (HID). Commands (the payload) are injected and executed using DuckyScript (the macro scripting language developed as part of the 'USB Rubber Ducky' BadUSB project).
U2F (Universal 2nd Factor)
Use the flipper as a second authentication factor for your Google account and others
HID controllers
Flipper Zero can replace certain HID (human interface device) controllers. This allows it to interact with your phone or computer. It can remotely control media players, computer keyboards or mouse, presentations, and more.
Keynote: Presentations remote
Keyboard: Double as a keyboard for a computer
Media: Controls media on a computer, camera remote control for a phone
Mouse: Double as a mouse for a computer
TikTok Controller: Control TikTok app on a phone
Mouse Jiggler: Duplicate mouse movements on a computer to keep computer showing as active at all times
PTT : use the flipper as a PTT (push to talk) controller / wireless PTT remote
Bans, seizure, police bulletin and other incidents
U.S. Customs seizure and release
In late 2022, U.S. Customs and Border Protection seized a shipment of 15,000 devices, but they were eventually released.
Amazon ban
On 7 April 2023, Amazon banned sales of the Flipper Zero via their site for being a "card skimming device". Only WiFi development boards, screen protectors and cases are still available from the site after the ban. Since 20th of September 2022 the Flipper Zero is available again on amazon.com.
Brazil seizures
In 2023 people in Brazil who ordered Flipper Zeros reported that their orders had been seized by Anatel. According to the Electronic Frontier Foundation, Anatel has flagged the devices as being a tool for criminal purposes, making the certification process complicated. Users have tried getting their devices certified, but to no avail. The EFF has said that the seizures would limit the ability of Brazilian cybersecurity researchers to conduct research, as they have legitimate uses for the device.
Police bulletin on Flipper Zero
In August 2023, The Daily Dot published an article on a bulletin for police officers published by the South Dakota Fusion Centre. The document suggested that extremists might use the device to bypass access control systems controls, particularly on power stations. The bulletin admitted there was no concrete evidence of plans by said extremists to use the device, though interest had been expressed on online forums.
Flipper CEO Pavel Zhovner was shown a copy of the bulletin and said that the Flipper Zero had been deliberately designed to not affect modern access control systems. He also pointed out that the bulletin itself said that gates at power stations were not inherently vulnerable to the device but that older gates might be.
Gatwick seizure
On 27 September 2023 a security staff member at Gatwick Airport confiscated a Flipper Zero from Vitor Domingos due to security concerns. The device was then handed over to Sussex Police.
Midwest FurFest Bluetooth Low Energy attack
In September 2023 the ability to launch Bluetooth Low Energy spam attacks with a Flipper Zero was demonstrated by a security researcher known as 'Techryptic'. A custom Flipper Zero firmware was developed shortly afterward that could launch spam attacks against Android devices and Microsoft Windows computers. An Android app to launch BLE attacks was developed shortly afterwards.
At the 2023 Midwest FurFest attendees reported severe disruption of Square payment readers and an insulin pump controller crashed due to the BLE spam. A researcher known as Remy said to Bleeping Computer :"For BTLE enabled medical equipment, at minimum a disruption results in a degraded quality of life for those affected," adding "Some conditions may not be life threatening to have disruptions. Others may not be so lucky."
As a result, a Python script was developed by the Wall of Flippers project for Linux and Windows to detect BLE spam attacks coming from Flipper and Android devices.
Potential Canadian ban
In February 2024, Innovation, Science, and Economic Development Canada announced that they had the intention of banning the Flipper Zero and other devices that could be used to clone wireless signals for remote entry in response to a significant increase in auto thefts.
On 20 March 2024, ISED announced that it would ban the use of the Flipper for illegal acts, but not ban it outright.
References
Radio-frequency identification
Kickstarter-funded products
ARM-based computers
Mobile computers
Products introduced in 2020
Handheld virtual pets | Flipper Zero | [
"Engineering"
] | 3,055 | [
"Radio-frequency identification",
"Radio electronics"
] |
70,885,850 | https://en.wikipedia.org/wiki/Scope%20soldering%20iron | The "Scope" soldering iron is a tool for soldering with lead-tin alloys, made in Australia since 1950, and intended for occasional or intermittent use. It has the virtue of quickly coming up to soldering temperature (~300C) and delivering considerable heat to a small area, but requires care to avoid overheating. It operates on low voltage (3–6V) and high current (tens of amps) from a battery or suitable transformer, so is by design electrically safe, and as it cools down rapidly when it leaves the operator's hand, should not constitute a fire risk.
Principle of operation
The soldering iron's "element" is a small carbon tip at the end of a pushrod connected to one terminal of the power supply, inside the stainless-steel barrel of the tool, but insulated from it. The barrel and its copper tip (the "bit"), is connected to the other terminal. When the user operates the pushrod, the carbon element bears against the back of the "bit", resulting in electric heating of the resistive carbon. The user modulates the temperature of the "bit" by the pressure they exert on the pushrod, through a lever or sliding ring, depending on the model.
The carbon element and copper "bit" are replaceable.
History
The original manufacturer, Scope Laboratories, of Melbourne, Australia, was a company founded in 1949 by two recent Czech immigrants, Richard Seligman and Egon Jelinek. With their families, they met on the journey to Australia in 1948. Seligman, an electrical engineer, had already been manufacturing oscilloscopes (colloquially "scopes") in Prague and had the intention to do the same in Australia. However after arrival, he found that there were no suitable soldering irons available for electronics manufacture. At the suggestion of his wife, Lise, who also became a partner in the business, he and Jelinek, who was a mechanical engineer, designed and built the novel soldering iron which heated up in a matter of seconds rather than minutes. It was much lighter than a conventional 100 watt iron (eg "Birko") and safer because it only remained hot whilst in use. This soldering iron became popular for electronic, mechanical and hobbyist work in Australia.
Production of Scope soldering irons started in January 1949 in the residence of the Seligman family in Duffy Street North Essendon, but quickly moved to 417 Keilor Road, Essendon, Victoria and (later) 3 Walton Street, Airport West, Victoria.
The "Scope" soldering iron when marketed in Australia in 1950, retailed at 43/6 (43 shillings and six pence, which converts to $4.35 before inflation), twice the price of a conventional iron. A suitable transformer was marketed (which doubled as a stand for the iron), also a metal etching pen "Vibroscope", which used the same transformer
and the same basic handle. In the 1970s the company also manufactured a cordless pistol-grip soldering iron, which contained two nickel-cadmium rechargeable batteries, and worked on the same principle. When Seligman and Jelinek retired in 1973, Scope Laboratories was sold to Peninsula Bus Lines. Later, Scope Laboratories was a wholly-owned subsidiary of Constructors, Developers and Fabricators Ltd., of which Bruce Small was a director and major shareholder.
The iron is still made and sold in Australia in its original (black handle) form, as well as an orange-handled version, dating from the 1970s, whose "sliding ring" also serves as a finger guard.
There is also a "Mini-Scope", introduced in 1965, of smaller dimensions, which has a lever to operate the pushrod. The manufacturer (Warren and Brown) markets a suitable encapsulated 3volt transformer, which also serves as a soldering-iron stand.
Gallery
References
Hand tools
Electronics work tools
Soldering
Australian inventions | Scope soldering iron | [
"Engineering"
] | 822 | [
"Human–machine interaction",
"Hand tools"
] |
70,887,148 | https://en.wikipedia.org/wiki/Sunit%20Kumar%20Singh | Indian Molecular Virologist
Sunit Kumar Singh is an Indian molecular virologist and professor of Molecular Immunology & Virology at the Institute of Medical Sciences, Banaras Hindu University. Currently, he is the director of the Dr. B R Ambedkar Center for Biomedical Research (ACBR), New Delhi.
Education and career
Sunit Kumar Singh earned his PhD in 2005 from University of Wuerzburg in Germany. Prof. Singh has been a scientist at CSIR-Centre for Cellular and Molecular Biology (CCMB), Hyderabad from 2006 to 2014. Dr. Singh led a research group in the area of neurovirology and inflammation biology as a scientist at CSIR-Centre for Cellular and Molecular Biology (CCMB), Hyderabad. In 2014, he joined the Banaras Hindu University (BHU), Varanasi, India. Prof. Singh has been Head of the Molecular Biology Unit, Institute of Medical Science, BHU, Varanasi for more than eight years. In addition, he has been the Professor Incharge of Center of Experimental Medicine & Surgery at the Institute of Medical Sciences, BHU, Varanasi for about five years Prior to these, Prof. Singh has worked in research roles at University of California, and School of Medicine, Yale University. In March 2023, Prof. Singh has been appointed as the Director of the Dr B R Ambedkar Center for Biomedical Research (ACBR), New Delhi in year 2023. In addition, Prof. Singh is also the Director of the Delhi Scool of Public Health (DSPH), Institution of Eminence, University of Delhi.
Awards
Sunit K. Singh, received many awards and fellowships for his contribution in the area of virology. Prof. Singh has been quite active in disseminating the right information to the society during various virus outbreaks such as: SARS-CoV2 and Monkeypox outbreaks as a part of his public outreach activity.
Elected Fellow of the National Academy of Medical Sciences (FAMS)
Elected Fellow of the National Academy of Sciences India (FNASc)
Elected Fellow of the Royal Society of Biology (FRSB)
Elected Fellow of Indian Academy of Neuroscience (FIANS)
Professor Sohail Ahmad Award' of Indian Academy of Biomedical Sciences
ICMR- Prof. B. K. Aikat Oration Award for Tropical Diseases
NAVBD-Molecular Biology Award
ICMR-Chaturvedi Ghanshyam Das Jaigopal Memorial Award for Immunology
ICMR-Dr. J. B Srivastav Memorial Oration Award for Virology
Publications
Sunit K. Singh contributed to the area of neurovirology and inflammation biology. Prof. Singh has published his research findings in various international peer reviewed journals in the area of Molecular Virology. In addition to his original research publications in high impact factor peer reviewed journals, Prof. Singh has published many books in the area of Infectious Diseases such as: Neuroviral Infections- Vol-I and Vol-II, Viral Hemorrhagic Fevers, Human Respiratory Viral Infections by CRC Press/ Taylor & Francis group, USA, Neglected Tropical Diseases-South Asia, Defense Against Biological Attacks- Vol-I and Vol-II by Springer, USA;Viral Infections and Global Change, Human Emerging and Re-emerging Infectious Diseases- Vol-I and Vol-II by Wiley Blackwell Publications, USA. Prof. Singh has been associated with many reputed peer reviewed International journals as Deputy Editor, Section Editor and Editorial Board Member. Prof. Singh contributed immensely in understanding the molecular pathogenesis of different neurotropic viruses.
References
External links
Sunit K. Singh - Google Scholar
Academic staff of Banaras Hindu University
Living people
Scientists from Uttar Pradesh
Molecular biologists
Indian virologists
Indian biologists
Year of birth missing (living people) | Sunit Kumar Singh | [
"Chemistry"
] | 791 | [
"Biochemists",
"Molecular biology",
"Molecular biologists"
] |
70,887,546 | https://en.wikipedia.org/wiki/Arsenite%20bromides | The arsenite bromides are mixed anion compounds containing both arsenite and bromide ions. Similar compounds include arsenate bromides, arsenite chlorides, antimonite bromides, antimonite chlorides, and ...
They are in the category of halide oxidoarsenates(III)
List
References
Arsenites
Bromides
Mixed anion compounds | Arsenite bromides | [
"Physics",
"Chemistry"
] | 85 | [
"Matter",
"Mixed anion compounds",
"Salts",
"Bromides",
"Ions"
] |
70,888,472 | https://en.wikipedia.org/wiki/Antimonide%20iodide | Antimonide iodides or iodide antimonides are compounds containing anions composed of iodide (I−) and antimonide (Sb3−). They can be considered as mixed anion compounds. They are in the category of pnictide halides. Related compounds include the antimonide chlorides, antimonide bromides, phosphide iodides, and arsenide iodides.
List
References
Antimonides
Iodides
Mixed anion compounds | Antimonide iodide | [
"Physics",
"Chemistry"
] | 107 | [
"Ions",
"Matter",
"Mixed anion compounds"
] |
70,889,053 | https://en.wikipedia.org/wiki/Syair%20Bidasari | The Syair Bidasari is a Malay poem popular across Southeast Asia. Surviving manuscripts date to the early 19th century, and the story may be older. Following a beautiful maiden who falls into a deathlike sleep during the day, it has been compared to the European fairy tales of Snow White and Sleeping Beauty.
Plot
A king and his pregnant wife flee an attack by a garuda. The queen gives birth along the way. Due to the danger, they place their newborn daughter in a boat on a riverbank and leave her there. A merchant finds the infant and raises her as his own, naming her Bidasari. He and his wife place her soul into a small fish, which they hide within a casket in a pond in their garden. Bidasari grows into a beautiful girl.
Djouhan Mengindra, Sultan of Indrapura, is married to the beautiful but vain Lila Sari. Lila Sari becomes consumed with worry that she'll be replaced as his favorite wife. She sends four servants to seek out any girl more beautiful than her, leading to the discovery of Bidasari. She commands that Bidasari be brought to her, claiming that she will treat her like an adopted daughter. Her parents reluctantly allow her to go. When Bidasari arrives, the Queen locks her up and beats her. The Queen wants to kill her but is thwarted until the despondent Bidasari – who believes her parents have abandoned her – tells her about the fish containing her soul. If she removes the fish from the water during the day, Bidasari will die. The Queen obtains the fish and wears it on a ribbon around her neck, and Bidasari swoons. Triumphant, the Queen has her body sent home. Her father hopes to revive her using the fish, only to discover that it’s been stolen. At midnight, Bidasari returns to life and tells her parents what happened, but she “dies” again at dawn. Her parents, terrified of the queen, build a refuge in the wilderness which they name Pengtipourlara. There they leave Bidasari alone for her safety, visiting regularly with supplies.
King Djouhan dreams about the Moon falling to Earth. When told that the dream means he will find a beautiful and deserving wife, he denies that anyone could ever equal Lila Sari. He goes on a hunting trip, only for his servants to discover Bidasari's refuge. The King orders them to break open the gates, enters alone and finds the dead Bidasari. He is struck by her beauty, and tries unsuccessfully to wake her. He returns again the next day, and stays until night when she awakes.
Bidasari is alarmed, but the King declares his love, explains who he is and states his wish to marry her. Bidasari tells him about the Queen, before swooning again as dawn approaches. He returns home, where he notices the fish on the Queen’s necklace and realizes that Bidasari was telling the truth. He takes the fish and at that moment, Bidasari is fully revived. The King returns and marries her in a magnificent wedding, building her a new palace. He invites Lila Sari to make amends with Bidasari, but she insults them both until he leaves in anger.
Meanwhile, Bidasari’s biological parents are once again reigning in their kingdom. Her brother learns of her story and decides to search for her. He successfully tracks her down and meets her foster family and husband. Bidasari is initially conflicted, wondering why her parents abandoned her, but the prince explains their story, and they arrange for a family reunion on the isle of Nousa Antara. There, the prince goes on a hunting trip which leads him to a palace. He fights an Ifrid and rescues a maiden named Princess Mendoudari, whom he brings back as his bride. The royal families are overjoyed when he returns, having thought him lost. With the celebrations coming to an end, they return to their kingdoms to live in peace and prosperity, with Bidasari’s story spread far and wide. Lila Sari is left alone in solitude to repent.
History
Syair Bidasari is a romantic syair, part of a genre popular in the 18th and 19th centuries. It was translated into other languages such as English, French, German and Russian. Julian Millie found that it was known across Southeast Asia from the Minangkabau region of Indonesia to the island of Mindanao.
The exact location of origin is unknown, and the date is uncertain, except that it was in circulation before the early 1800s, with the earliest mention of the title from 1807 and the earliest extant manuscript dated 1814. A similar work, the Syair Ken Tambuhan, is dated 1791 and was theorized to have been composed no earlier than 1650. The story may have also existed in a prose form known as hikayat, with Dr. J. Leyden mentioning the "Hikaiat Bida Sari" in 1807.
Analysis
Malaysian literary scholar Siti Hawa Salleh identified this as one of the hikayat in syair form with both Indian and Middle Eastern elements, alongside Syair Siti Zubaidah and Syair Dandan Setia. The poem's intricate language has made it difficult to translate into English with full accuracy.
Adaptations
Bidasari (1965 film)
Bidasari (play)
See also
Princess Aubergine
References
English translations
Poems in Malay
19th-century poems
Anonymous works
Syairs
Works of unknown authorship
Sleep in mythology and folklore | Syair Bidasari | [
"Biology"
] | 1,140 | [
"Behavior",
"Sleep",
"Sleep in mythology and folklore"
] |
70,889,655 | https://en.wikipedia.org/wiki/Magic%20Kombat | Magic Kombat is a 1995 Philippine sci-fi fantasy comedy film written and directed by Junn Cabreira. The film stars Smokey Manaloto and Eric Fructuoso, and centers around Mario (Manaloto) and Luigi (Fructuoso) as they are accidentally transported into a video game world and are forced to fight their way out of it. Many of the film's scenarios, sound effects and characters–including that of Mario and Luigi–were unauthorized parodies of Super Mario Bros., Street Fighter II and other video games popular in the Philippines during the 80s and 90s.
It was one of the entries in the 1995 Metro Manila Film Festival.
Plot
Working students Mario (Manaloto) and Luigi (Fructuoso), become recently-unemployed after an incident at a mall and struggle to make ends meet until they find employment as janitors and technicians at a school, where they get a chance to study.
When a video game character named Rio suddenly gets materialized into the real world during a gaming session by Mario on a stormy night, the Mario brothers along with their friend Diana set out to get Rio back to her home world, but things get complicated when Mario and Luigi are sucked into the video game realm instead of Rio. The two brothers are then forced to fight their way through each of the game's levels and are later aided by Rio who made her way back to her home realm. After a final encounter with supernatural creatures in a cave, Mario and Luigi use the gems they retrieved from their previous encounters, unlocking the door which leads them back to the real world.
Back in their old job as janitors, Mario and Luigi chance upon a student who bears a striking resemblance to Rio.
Cast
Smokey Manaloto as Mario
Eric Fructuoso as Luigi
Dandin Ranillo as Janitor
Beth Tamayo as Diana
Joanne Pascual as Rio
Sharmaine Suarez as Blanka
Ernie Ortega as Samurai Man
Aga Fazon as Gorilla
Jan Cassie Espolong as Goko
Cita Astals as School Dean
Jaime Fabregas as Asst. Dean
Francis Enriquez as Student
Nonong de Andres as Albularyo
Solita Carreon as Recruiter
Cris Daluz as Uncle Teong
Awards
Notes
References
External links
1995 films
1995 fantasy films
1990s parody films
1990s science fiction adventure films
Filipino-language films
Philippine fantasy comedy films
Philippine parody films
Philippine science fiction comedy films
Films about artificial intelligence
Films about computing
Films about video games
Metafictional works
Moviestars Production films
Parodies of video games
Unofficial works based on Mario
Works about janitors
Works based on Street Fighter
Works about Nintendo
1995 science fiction films | Magic Kombat | [
"Technology"
] | 537 | [
"Works about computing",
"Films about computing"
] |
70,890,547 | https://en.wikipedia.org/wiki/HD%20193472 | HD 193472 (HR 7774) is a solitary star in the equatorial constellation Delphinus. It has an apparent magnitude of 5.94, making it visible with the naked eye if viewed under ideal conditions. Parallax measurements put it at a distance of 282 light years and has a radial velocity of , indicating that the object drifting towards the Solar System.
HD 193472 has a stellar classification of kA4 hF0 mF2, indicating that its an Am star with the calcium K-line of an A4 star, the hydrogen lines and effective temperature of a F0 star, and the metallic lines of a F2 star. Due to a radius over three times that of the Sun and a relatively low surface gravity, it appears to be slightly evolved. HD 193472 has 161% the mass of the Sun and shines at 24 times the luminosity of the Sun from its photosphere at an effective temperature of , giving it a yellowish white glow. HD 193472 has a projected rotational velocity of .
References
Delphinus
Am stars
193472
100256
7774
BD+13 4360 | HD 193472 | [
"Astronomy"
] | 235 | [
"Delphinus",
"Constellations"
] |
70,891,828 | https://en.wikipedia.org/wiki/Tammann%20and%20H%C3%BCttig%20temperatures | The Tammann temperature (also spelled Tamman temperature) and the Hüttig temperature of a given solid material are approximations to the absolute temperatures at which atoms in a bulk crystal lattice (Tammann) or on the surface (Hüttig) of the solid material become sufficiently mobile to diffuse readily, and are consequently more chemically reactive and susceptible to recrystallization, agglomeration or sintering. These temperatures are equal to one-half (Tammann) or one-third (Hüttig) of the absolute temperature of the compound's melting point. The absolute temperatures are usually measured in Kelvin.
Tammann and Hüttig temperatures are important for considerations in catalytic activity, segregation and sintering of solid materials. The Tammann temperature is important for reactive compounds like explosives and fuel oxiders, such as potassium chlorate (, TTammann = 42 °C), potassium nitrate (, TTammann = 31 °C), and sodium nitrate (NaNO3, TTammann = 17 °C), which may unexpectedly react at much lower temperatures than their melting or decomposition temperatures.
The bulk compounds should be contrasted with nanoparticles which exhibit melting-point depression, meaning that they have significantly lower melting points than the bulk material, and correspondingly lower Tammann and Hüttig temperatures. For instance, 2 nm gold nanoparticles melt at only about 327 °C, in contrast to 1065 °C for a bulk gold.
History
Tammann temperature was pioneered by German astronomer, solid-state chemistry, and physics professor Gustav Tammann in the first half of the 20th century. He had considered a lattice motion very important for the reactivity of matter and quantified his theory by calculating a ratio of the given material temperatures at solid-liquid phases at absolute temperatures. The division of a solid's temperature by a melting point would yield a Tammann temperature. The value is usually measured in Kelvins (K):
where is a constant dimensionless number.
The threshold temperature for activation and diffusion of atoms at surfaces was studied by :de:Gustav Franz Hüttig, physical chemist on the faculty of Graz University of Technology, who wrote in 1948 (translated from German):
Description
The Hüttig temperature for a given material is
where is the absolute temperature of the material's bulk melting point (usually specified in Kelvin units) and is a unitless constant that is independent of the material, having the value according to some sources, or according to other sources. It is an approximation to the temperature necessary for a metal or metal oxide surfaces to show significant atomic diffusion along the surface, sintering, and surface recrystallization. Desorption of adsorbed gasses and chemical reactivity of the surface often increase markedly as the temperature is increases above the Hüttig temperature.
The Tammann temperature for a given material is
where is a unitless constant usually taken to be , regardless of the material. It is an approximation to the temperature necessary for mobility and diffusion of atoms, ions, and defects within a bulk crystal. Bulk chemical reactivity often increase markedly as the temperature is increased above the Tammann temperature.
Examples
The following table gives an example Tammann and Hüttig temperatures calculated from each compound's melting point Tmp according to:
TTammann = 0.5 × Tmp
THüttig = 0.3 × Tmp
See also
Notes
References
Heat_transfer
Thermodynamic properties | Tammann and Hüttig temperatures | [
"Physics",
"Chemistry",
"Mathematics"
] | 698 | [
"Transport phenomena",
"Physical phenomena",
"Heat transfer",
"Thermodynamic properties",
"Physical quantities",
"Quantity",
"Thermodynamics"
] |
70,892,927 | https://en.wikipedia.org/wiki/Arne%20Magn%C3%A9li | Arne Magnéli (6 December 1914 – 22 July 1996) was a Swedish chemist and crystallographer known for his work on the structure determination of transition metal oxides and alloys, including the study into their homologous series and nonstoichiometric phenomenon.
Education and career
Magnéli studied at Stockholm University and graduated with a Licentiate in 1941. He moved to Uppsala University to conduct his graduate research under Gunnar Hägg, obtaining his PhD in 1950 for the study on tungsten bronzes. He took up a teaching position at Stockholm University in 1953, and later became the Chair of Inorganic Chemistry at the university until his retirement in 1980.
From his research into the structures of transition metal oxides, Magnéli developed the concept of recurrent dislocations, which nowadays is known as crystallographic shear. The Magnéli phases of transition metal oxides, such as nonstoichiometric tungsten oxide, molybdenum oxide, titanium oxide, and vanadium oxide are named after him.
Honors and awards
Magnéli was awarded the Gregori Aminoff Prize of the Royal Swedish Academy of Sciences in 1989. He served as the secretary of the Nobel Committee for Physics from 1966 to 1973 and the Nobel Committee for Chemistry from 1966 to 1986.
External links
Publications of Arne Magnéli in Acta Chemica Scandinavica
References
1914 births
1996 deaths
Swedish chemists
Stockholm University alumni
Academic staff of Stockholm University
Crystallographers
Uppsala University alumni
People from Stockholm
Members of the Royal Swedish Academy of Sciences
Solid state chemists
Presidents of the International Union of Crystallography | Arne Magnéli | [
"Chemistry",
"Materials_science"
] | 328 | [
"Solid state chemists",
"Crystallography",
"Crystallographers"
] |
70,893,492 | https://en.wikipedia.org/wiki/1986%20Iquique%20arms%20factory%20explosion | On January 25, 1986, a large explosion occurred at the Cardoen Armaments Factory in the Alto Hospicio industrial suburb of the coastal Chilean city Iquique, killing 29 workers and seriously injuring 11. Only four bodies were recovered, with the others vaporised by the blast, according to Irene Rojas, a reporter for the Iquique newspaper La Estrella. The plant, one of five arms factories owned by industrialist Carlos Cardoen, was the largest in Chile at the time. The explosion occurred in the cluster bomb arming section of the plant, which had been exporting the 500 pound bombs to Iraq for use during the Iran–Iraq War since 1983. According to Luis Narváez, a reporter investigating Chile's arms dealing and Pinochet's offshore bank accounts for La Nación, there was a persistent rumor among Chileans that the explosion was the result of sabotage, possibly committed by Chilean soldiers. The given motive for this alleged attack was to punish Cardoen for not cooperating fully with a "mafia like" syndicate of Chilean arms manufacturers, and for providing too much competition for other manufacturers such as FAMAE.
See also
Río Tercero explosion
References
Industrial fires and explosions
1986 disasters in Chile
History of Tarapacá Region
Military dictatorship of Chile (1973–1990)
Explosions in 1986
Explosions in Chile
1986 industrial disasters
Military history of Chile
January 1986 events in South America | 1986 Iquique arms factory explosion | [
"Chemistry"
] | 286 | [
"Industrial fires and explosions",
"Explosions"
] |
67,994,869 | https://en.wikipedia.org/wiki/C/2014%20UN271%20%28Bernardinelli%E2%80%93Bernstein%29 | (Bernardinelli–Bernstein), simply known as or Comet Bernardinelli–Bernstein (nicknamed BB), is a large Oort cloud comet discovered by astronomers Pedro Bernardinelli and Gary Bernstein in archival images from the Dark Energy Survey. When first imaged in October 2014, the object was from the Sun, almost as far as Neptune's orbit and the greatest distance at which a comet has been discovered. With a nucleus diameter of at least , it is the largest Oort cloud comet known. It is approaching the Sun and will reach its perihelion of 10.9 AU (just outside of Saturn's orbit) in January 2031. It will not be visible to the naked eye because it will not enter the inner Solar System.
Observational history
Discovery
was discovered by astronomers Pedro Bernardinelli and Gary Bernstein in an algorithm-assisted search for slowly-moving trans-Neptunian objects, in archival images from the Dark Energy Survey (DES) at Cerro Tololo Inter-American Observatory. It was detected at the 22nd apparent magnitude in 42 DES images spanning 10 October 2014 to 26 November 2018. The long observation arc by the DES images revealed that the object was on a near-parabolic trajectory inbound towards the Solar System, implying a cometary origin from the Oort cloud, despite the object's apparently asteroidal (point-like) appearance in the images. When first imaged by the DES, the object was located in the southern constellation Sculptor, inside the orbit of Neptune at a distance of from the Sun. The object's relatively high brightness from its distance indicated that its diameter must be on the order of —an exceptionally large size for an object of cometary origin.
The discovery was announced by the Minor Planet Center on 19 June 2021, and the object was given the minor planet provisional designation . The object attracted significant attention from astronomers worldwide: astronomers made follow-up observations and found several precoveries within days of the announcement. The earliest precovery observations of were obtained from Paranal Observatory's VISTA survey images taken on 15 November 2010, when the object was from the Sun.
Cometary activity
Cometary activity in was first reported on 22 June 2021, by Tim Lister at Las Cumbres Observatory's telescope in Sutherland, South Africa and by Luca Buzzi at the SkyGems Remote Telescope in Namibia. The comet was found to be one magnitude brighter than predicted in their observations, with a slightly asymmetric coma up to 15 arcseconds in width. At that time, the comet's distance from the Sun was . The detection of cometary activity was confirmed by the Minor Planet Center and the comet was formally named (Bernardinelli–Bernstein) on 24 June 2021.
Analysis of archival images from NASA's Transiting Exoplanet Survey Satellite (TESS) show that had an extensive, diffuse coma at least 43 arcseconds wide in observations as early as September 2018, when it was from the Sun. Between the 2018 and 2020 TESS observation epochs, the comet's brightness had significantly increased by 1.5 magnitudes, likely as a result of continuous activity rather than a spontaneous outburst.
Reexamination of other telescope datasets have also identified a diffuse and distinctly asymmetric coma in DES images beginning from 2017 (at 25.1 AU) and Pan-STARRS 1 images beginning from 2019 (at 22.6 AU). 's coma brightness has been growing exponentially since 2017, while the comet's overall brightness had remained steady in 2014–2018, hinting that activity may have well begun prior to the comet's discovery at 29.0 AU. The observation of cometary activity from such large heliocentric distances is rare: only three other comets, Comet Hale–Bopp (27.2 AU outbound), C/2010 U3 (Boattini) (25.8 AU inbound), and C/2017 K2 (PanSTARRS) (24.0 AU inbound), have been observed to exhibit activity at heliocentric distances greater than 20 AU. , holds the record for the greatest distance at which a comet has been discovered in the Solar System.
was observed by the Hubble Space Telescope in January, March, July, August, and October 2022.
2021 outburst
On 9 September 2021, an apparent outburst of was detected at Las Cumbres Observatory, as reported on 14 September. It brightened by 0.65 magnitudes compared to images taken earlier that day, and reached an apparent magnitude of 18.9. Calculations based on this brightening indicate that of dust was ejected during the outburst. At the time, the comet was from the Sun. The comet's brightness has since faded back down to the 19th magnitude by December 2021.
Occultations
Rigorous computations of 's orbit and ephemeris have identified few potential occultation events by the comet from 2021–2025, during which the comet would pass in front of a bright star and briefly block out the star's light. Observing these occultation events would allow for opportunities to make precise measurements of the comet's size and position, as well as search for surrounding dust and possible satellites. The first attempt at observing one of those occultations was made from Australia and New Zealand on 19 September 2021, but was unsuccessful due to poor weather conditions.
Visibility
With a current declination of below the celestial equator, is best seen from the Southern hemisphere. The evolution of its cometary activity will soon be monitored by the upcoming Vera C. Rubin Observatory starting 2023. Once at perihelion, the comet is not expected to get brighter than Pluto (mag 13–16) and is more likely to reach the brightness of Pluto's moon Charon (mag 16.8) as the comet does not enter the inner Solar System where comets become notably more active. Even if it reaches the magnitude of Pluto, it will require about a telescope to be visually seen.
Nucleus properties
Size and mass
Radio thermal emission measurements by the Atacama Large Millimeter Array (ALMA) in 2021 estimate a maximum diameter of for 's nucleus, assuming negligible contamination of the nucleus's thermal emission by an unseen dust coma. The ALMA measurements have not ruled out the possibility of a dust coma contaminating up to 24% of the nucleus's thermal emission, so the actual diameter may well be smaller. Hubble Space Telescope observations confirmed 's large size in 2022, placing a lower limit diameter of for the maximum possible dust coma contamination.
Even at its minimum estimated diameter, is the largest Oort cloud comet discovered, being more than 50 times larger than a typical comet which is less than in diameter. The previous largest known long-period comet was (LINEAR) with a diameter of , followed by Comet Hale–Bopp at . The only known comet larger than is the active centaur 95P/Chiron, which has a diameter of approximately .
While the mass and density have not yet been measured, a rough estimate by NASA places its mass at , about 100,000 times greater than that of a typical comet.
Albedo and color
Without its coma, the nucleus of has a visual (V-band) absolute magnitude of , which is calculated from its distance and apparent magnitude. Given the minimum estimated diameter (119 km) and absolute magnitude, the nucleus is calculated to have a very low visual geometric albedo up to , meaning that it reflects only of visible light—making its surface darker than coal. For the maximum estimated diameter (137 km), the minimum albedo of the nucleus would be . 's low albedo is characteristic of small comet nuclei from both short- and long-period populations, suggesting a lack of correlation between albedo, nucleus size, and orbit type in Solar System comets. The low albedos of cometary nuclei are generally attributed to the deposition of carbon, organic compounds, and sulfides produced by cosmic rays dissociating molecules on the nucleus's surface.
Optical observations of during its inbound passage show that its nucleus appears more reflective at longer wavelengths, indicating a moderately red color similar to (albeit slightly less red than) most long-period comets. The albedo and color of 's nucleus are expected to change over time due to cometary activity, especially after perihelion passage when temperatures decrease; its nucleus is massive enough to gravitationally recapture deposited icy ejecta back onto its surface, similar to what has been observed on Comet Hale–Bopp after its perihelion.
Rotation
The rotation period of 's nucleus is disputed, as some studies found no significant rotational periodicity in its light curve. Continuous observations by TESS in 2018 and 2020 did not detect any periodicity, placing an upper limit of 0.3 magnitudes for the nucleus's amplitude of variability. In 2021, Bernardinelli and collaborators from the DES analyzed various ground-based telescope datasets from 2018 and earlier, finding an apparent nucleus variability of 0.2 magnitudes, but no periodicity due to sparse data. Bernardinelli et al. do not rule out other factors such as small dust outbursts that may contribute to this apparent variability, leaving room for the possibility that the nucleus's true rotational variability may be even less than 0.2 magnitudes. In April 2022, astronomers Ignacio Ferrin and A. Ferrero reported a nucleus rotation period of days, based on an analysis of 's long-term light curve behavior in observations from the Minor Planet Center's database. Ferrin and Ferrero found a nucleus light curve amplitude of magnitudes, incongruous with findings by TESS and Bernardinelli et al.
Cometary properties
The exponential brightening of 's coma at 20–25 AU is consistent with it being generated by sublimating carbon dioxide (CO2) or ammonia (NH3) ices from the nucleus's surface. Less abundant supervolatile substances such as carbon monoxide (CO) are likely present in and may additionally contribute to its distant activity, but their emissions remain yet to be detected. Infrared NEOWISE observations from November 2020 did not detect any CO gas emission from at 20.9 AU, placing an upper limit CO outgassing rate at about ten times that of Comet Hale–Bopp at the same heliocentric distance.
Analysis of 's coma shape in TESS images from 2018–2020 suggests that the coma is composed of submillimeter-sized dust grains ejected at low speeds around , indicating that the comet had become active 2 to 10 years prior to 2018. Based on the coma's brightness in Hubble observations from January 2022, is losing mass at a rate of roughly at 20 AU, similar to Comet Hale–Bopp at this distance.
Orbit and origin
came from the Oort cloud and has been inside of the orbit of Neptune (29.9 AU) since March 2014 and passed inside the orbit of Uranus (18.3 AU) in September 2022. The time of perihelion has been well-known since June 2021. The current 3-sigma uncertainty in the comet's distance from the Sun is ±35,000 km.
The inbound and outbound orbital period of an Oort cloud comet are never exactly the same as the orbit changes as a result of planetary perturbations. For an Oort cloud comet an orbit defined while inside of the planetary region can produce results that are misleading. Therefore, the inbound and outbound orbits should be computed before entering the planetary region and after leaving the planetary region. With an observation arc of several years using dozens of observations, the orbit of is securely known. Its incoming orbit in 1600, as calculated by JPL Horizons, has a semimajor axis of . This indicates that was at its furthest distance, or aphelion, of in the Oort cloud around 1.4 million years ago. It will come to perihelion (closest approach to the Sun) around 23 January 2031 at a distance of , just outside the aphelion of Saturn's orbit (10.1 AU). It will make its closest approach to Earth around 5 April 2031 at a distance of . It will cross the ecliptic plane on 8 August 2033 when it is outbound from the Sun. Its outbound orbital period will be approximately 4.6 million years with an aphelion distance of about . The object is only very loosely bound to the Sun and subject to perturbations by the galactic tide while in the Oort cloud.
Large, long-period comets such as are rarely found due to a phenomenon known as fading: comets on bound orbits around the Sun periodically lose mass and volatile content to activity in each perihelion passage, resulting in a gradual diminishing in size, brightness, and activity as they age. This adds further evidence to being a dynamically new comet.
Exploration
there are no mission proposals to , nor are there any upcoming missions that can be retargeted to the comet. The European Space Agency's upcoming Comet Interceptor mission, which will launch in 2029 and make a flyby of a long-period comet within Earth's orbit, will not be able to reach due to its large perihelion distance.
According to a 2021 study by the Initiative for Interstellar Studies, a future flyby mission with a direct, low-energy trajectory to can have yearly optimal launch windows between September and October throughout 2022–2029, for a maximum delta-v of 12 km/s at Earth. In all scenarios, the spacecraft would optimally arrive to at a relative velocity of 12–14 km/s by August 2033, when the comet crosses the ecliptic plane at 11.9 AU from the Sun. For instance a mission similar to New Horizons (with the same launch vehicle but no Jupiter encounter) could reach by August 2033 if launched in October 2029. Alternatively, a flyby trajectory to using a combined gravity assist and Oberth maneuver at Jupiter can have feasible launch dates from 2020–2027 and 2034–2037. A launch within the latter window could utilize an Earth flyby to Jupiter after completing a 1:1 Earth resonant orbit, which would significantly reduce the characteristic energy at Earth launch and allow for target arrival above the ecliptic. A flyby trajectory using consecutive gravity assists and orbital resonances from the inner planets is also possible, but the most optimal encounter combinations provide launch dates up to 2028, for a late 2033 arrival time.
A rendezvous trajectory to has been considered, although the comet's nearly-perpendicular orbit renders any direct rendezvous trajectory from the ecliptic unfeasible. Nonetheless, a rendezvous with can be performed with a Jupiter gravity assist after the comet has crossed the ecliptic, with optimal launch dates in 2030–2034 and flight durations around 14–15 years.
See also
List of Solar System objects by greatest aphelion
Notes
References
External links
C/2014 UN271 (Bernardinelli–Bernstein) – comet catalog page by Seiichi Yoshida, updated 5 February 2022
Giant Comet Found in Outer Solar System by Dark Energy Survey – NOIRLab press release, 25 June 2021
Non-periodic comets
Discoveries by Gary M. Bernstein
20141020
Oort cloud | C/2014 UN271 (Bernardinelli–Bernstein) | [
"Astronomy"
] | 3,121 | [
"Astronomical hypotheses",
"Oort cloud"
] |
67,994,965 | https://en.wikipedia.org/wiki/Nobe%20GT100 | The Nobe GT100 (pronounced no bay) is a zero emissions concept vehicle with two forward wheels and a single trailing wheel, each electrically powered. Originally designed as an enclosed two-door coupe, and subsequently rendered also as a two-door convertible, the GT100 (variously called the Nobe or Nobe 100) debuted at the 2019 Geneva Auto Show as the Nobe 01.
The Nobe was styled and promoted in Estonia by company founder Roman Muljar in 2017, with the idea production might happen in that country. After original development and two unsuccessful crowd-sourcing attempts, Nobe's Estonia workshop caught fire, destroying its two prototypes and underlying documentation, all uninsured. Developers turned to North America, where a non-running prototype was subsequently marketed by Nobe Cars USA, Inc.. The company at one time had worked with Sandy Munro and Munro & Associates to engineer the vehicle for production.
By late 2021, the companies surrounding the concept were mired in shareholder disputes and controversy. By 2022, development had stalled and the vehicle had not neared production.
Design
The Nobe 100 was projected to weigh 1,100 lbs and use rechargeable, portable 120v/240v batteries — for a projected driving range of 180 miles and projected top speed of 80 miles per hour.
The concept accommodated seating for two with a rear luggage area (or optional rear jump seat); front trunk; stability control; air-conditioning; fully integrated espresso machine Other illustrated features included seat-belts with integral airbags and a system marketed as Gekko, facilitated by the car's light weight, that would allow the car to be cable-winched up aluminum rails mounted to the side of a building, enabling "zero-footprint" parking.
Styling was described as "cute as hell. Like, Audrey Hepburn in white gloves cute. It's the car Edna Mode would drive." Still another said it is "classically beautiful in its treatment of lines and motion - the Nobe looks downright breathtaking."
Classification
The three-wheeler was marketed as off-road capable and would be classified in the United States as an autocycle, a regulatory class of three-wheeled vehicles requiring only a regular driver's license and exempt from federal automotive safety provisions when equipped with a steering wheel rather than handlebars, two side by side seats and seat belts (but not airbags). As of 2020, the classification existed in 48 states.
Controversy
Nobe Cars has had two failed crowdsourcing campaigns on Indiegogo and FundedByMe, both of which were only able to achieve about 15% of their goal. As of 2022, Nobe Cars USA, Inc. markets the company via their website, www.nobecars.com.
Controversy surfaced regarding the automaker when an investigative report on the Estonian news program Pealtnägija on the ERR network investigated and found criminal charges and past bankruptcies associated with the CEO, Roman Muljar, in addition to complaints by shareholders about his ability to run a business and misappropriation of funds. Video from the report was later released with English subtitles.
Allegations of assault against Nobe CEO Roman Muljar, along with accusations of poaching and investment theft, were made by an EV investor, who also reported to police being threatened with a glass bottle by Muljar at the Fully Charged EV show in Farnborough, UK in May 2022.
A group referring to itself only as nobecarsinvestors.com pointed to many problems with the company, offering comparisons to the Dale and Elio cars and to Nikola Motors. The group raises serious questions about "the nature and timing of the fire that destroyed" Nobe's factory in October 2019, and questioned how "a move to another facility was in the works before the fire even started." In multiple articles, the Estonian media note that the company was in severe financial distress at the time of the fire, while the investor group questions how a company that could not even pay a €1,700 tax bill, and claims to have neglected to get insurance, somehow had the finances to have a new factory completed just two months after the fire.
See also
Microlino
Polaris Slingshot
Elio Motors
Three-wheeler
Twentieth Century Motor Car Corporation
References
Electric vehicles
Sustainable transport
Concept cars
Three-wheeled motor vehicles
Electric three-wheel vehicles
All-wheel-drive vehicles
Electric concept cars
Retro-style automobiles | Nobe GT100 | [
"Physics"
] | 905 | [
"Physical systems",
"Transport",
"Sustainable transport"
] |
67,995,063 | https://en.wikipedia.org/wiki/Poelaert%20Elevators | The Poelaert Elevators (; ), in popular language Elevators of the Marolles (, ) is a public elevator in the Marolles/Marollen district of Brussels, Belgium. It connects the lower and upper town at the / with the /, in the vicinity of the Palace of Justice. The elevator consists of two independent elevators, hence the plural elevators (, ) sometimes used for its name.
Construction
The idea of building a means of transport connecting the Marolles/Marollen neighbourhood and the / is much older; in the 19th century, it was proposed to build a funicular for this purpose. In the early 1990s, the architect Patrice Neirinck of AVA Architects promoted the concept of building a vertical elevator. The proposal sought to "open up the Marolles district" and "revitalise the /", located at the bottom, making it a crossing point.
CFE was appointed as the general contractor, and the supply of the two elevators and the electromechanical systems were provided by Schindler Group. The architectural project was executed by the AVA Architects office, under the coordination of the architect Patrice Neirinck, while the Verdeyen & Moenaert took care of the stability study.
The construction cost about 78 million Belgian francs (equivalent to about €2 million), of which 51 million francs (about €1.25 million) for the bulk of the investment, and 27 million francs (about €676,000) for the elevators. Funding was provided by the Brussels-Capital Region and the Belgian Federal Government under a cooperation agreement. The Ministry of Communications and Infrastructure was in charge of the project management, receiving technical assistance from the Directorate of Electromechanical Constructions.
After the construction of the tower, the future metal walkway was installed between the upper part and the Place Poelaert. The walkway was made at Geel, Antwerp, and transported to Brussels by a special convoy, arriving on the esplanade at the Palace of Justice around 10:00 on 13 October 2001. The entire lift was inaugurated in June 2002 and became one of the area's most popular tourist attractions. Its administration and operation was entrusted by the municipality to the Brussels Intercommunal Transport Company (STIB/MIVB).
Operation
The operation of the new elevator was marked by numerous technical problems, the first being reported only one month after the inauguration, on 21 July 2002. In 2019, for example, STIB/MIVB had to intervene a total of 131 times to remedy the faults that occurred at the two elevators: 43 wedges in one of them, 88 wedges in the other. The main reasons that led to the shutdown of the elevators were the unfavorable weather conditions and vandalism.
In April 2018, 1,300 colored T-shirts were hung from the structure of the elevator, as part of the work entitled If I Had Wings, a cultural experiment by Finnish artist Kaarina Kaikkonen.
In July 2020, the Minister for Mobility and Public Works of the Brussels-Capital Region, Elke Van den Brandt, confirmed that the lift would be rehabilitated in the first quarter of 2021.
About a million people use the elevator every year.
Specifications
The Poelaert Elevators have the following specifications:
References
Notes
Buildings and structures in Brussels
Transport in Brussels
Transport infrastructure completed in 2002
Elevators | Poelaert Elevators | [
"Engineering"
] | 686 | [
"Building engineering",
"Elevators"
] |
67,995,256 | https://en.wikipedia.org/wiki/Identical-machines%20scheduling | Identical-machines scheduling is an optimization problem in computer science and operations research. We are given n jobs J1, J2, ..., Jn of varying processing times, which need to be scheduled on m identical machines, such that a certain objective function is optimized, for example, the makespan is minimized.
Identical machine scheduling is a special case of uniform machine scheduling, which is itself a special case of optimal job scheduling. In the general case, the processing time of each job may be different on different machines; in the case of identical machine scheduling, the processing time of each job is the same on each machine. Therefore, identical machine scheduling is equivalent to multiway number partitioning. A special case of identical machine scheduling is single-machine scheduling.
In the standard three-field notation for optimal job scheduling problems, the identical-machines variant is denoted by P in the first field. For example, " P||" is an identical machine scheduling problem with no constraints, where the goal is to minimize the maximum completion time.
In some variants of the problem, instead of minimizing the maximum completion time, it is desired to minimize the average completion time (averaged over all n jobs); it is denoted by P||. More generally, when some jobs are more important than others, it may be desired to minimize a weighted average of the completion time, where each job has a different weight. This is denoted by P||.
Algorithms
Minimizing average and weighted-average completion time
Minimizing the average completion time (P||) can be done in polynomial time. The SPT algorithm (Shortest Processing Time First), sorts the jobs by their length, shortest first, and then assigns them to the processor with the earliest end time so far. It runs in time O(n log n), and minimizes the average completion time on identical machines, P||.
There can be many SPT schedules; finding the SPT schedule with the smallest finish time (also called OMFT – optimal mean finish time) is NP-hard.
Minimizing the weighted average completion time is NP-hard even on identical machines, by reduction from the knapsack problem. It is NP-hard even if the number of machines is fixed and at least 2, by reduction from the partition problem.
Sahni presents an exponential-time algorithm and a polynomial-time approximation scheme for solving both these NP-hard problems on identical machines:
Optimal average-completion-time;
Weighted-average-completion-time.
Minimizing the maximum completion time (makespan)
Minimizing the maximum completion time (P||) is NP-hard even for identical machines, by reduction from the partition problem. Many exact and approximation algorithms are known.
Graham proved that:
Any list scheduling algorithm (an algorithm that processes the jobs in an arbitrary fixed order, and schedules each job to the first available machine) is a approximation for identical machines. The bound is tight for any m. This algorithm runs in time O(n).
The specific list-scheduling algorithm called Longest Processing Time First (LPT), which sorts the jobs by descending length, is a approximation for identical machines. It is also called greedy number partitioning.
Coffman, Garey and Johnson presented a different algorithm called multifit algorithm, using techniques from bin packing, which has an approximation factor of 13/11≈1.182.
Huang and Lu presented a simple polynomial-time algorithm that attains an 11/9≈1.222 approximation in time O(m log m + n), through the more general problem of maximin-share allocation of chores.
Sahni presented a PTAS that attains (1+ε)OPT in time . It is an FPTAS if m is fixed. For m=2, the run-time improves to . The algorithm uses a technique called interval partitioning.
Hochbaum and Shmoys presented several approximation algorithms for any number of identical machines (even when the number of machines is not fixed):
For any r >0, an algorithm with approximation ratio at most (6/5+2−r ) in time .
For any r >0, an algorithm with approximation ratio at most (7/6+2−r ) in time .
For any ε>0, an algorithm with approximation ratio at most (1+ε) in time . This is a PTAS. Note that, when the number of machines is a part of the input, the problem is strongly NP-hard, so no FPTAS is possible.
Leung improved the run-time of this algorithm to .
Maximizing the minimum completion time
Maximizing the minimum completion time (P||) is applicable when the "jobs" are actually spare parts that are required to keep the machines running, and they have different life-times. The goal is to keep machines running for as long as possible. The LPT algorithm attains at least of the optimum.
Woeginger presented a PTAS that attains an approximation factor of in time , where a huge constant that is exponential in the required approximation factor ε. The algorithm uses Lenstra's algorithm for integer linear programming.
General objective functions
Alon, Azar, Woeginger and Yadid consider a more general objective function. Given a positive real function f, which depends only on the completion times Ci, they consider the objectives of minimizing , minimizing , maximizing , and maximizing . They prove that, if f is non-negative, convex, and satisfies a strong continuity assumption that they call "F*", then both minimization problems have a PTAS. Similarly, if f is non-negative, concave, and satisfies F*, then both maximization problems have a PTAS. In both cases, the run-time of the PTAS is O(n), but with constants that are exponential in 1/ε.
See also
Fernandez's method
References
External links
Summary of parallel machine problems without preemtion
Optimal scheduling
Number partitioning | Identical-machines scheduling | [
"Engineering"
] | 1,243 | [
"Optimal scheduling",
"Industrial engineering"
] |
67,997,045 | https://en.wikipedia.org/wiki/HD%20212771 | HD 212771, also named Lionrock, is a solitary star in the southern zodiac constellation Aquarius. It has an apparent magnitude of 7.60, making it readily visible with binoculars but not the naked eye. Parallax measurements place the object at a distance of 364 light years, and is currently receding with a radial velocity of .
HD 212771 has a stellar classification of G8 IV, indicating that it is a subgiant evolving towards the red giant branch after being an F-type main-sequence star for 1.7 billion years. It has 142% the mass of the Sun and 4.4 times its radius. It radiates at from its slightly enlarged photosphere at an effective temperature of 5,065 K, giving it a yellow-hue. Unlike most planetary hosts, HD 212771 is slightly metal deficient, and spins with a projected rotational velocity of about .
Planetary system
In 2010, a group of astronomers at the Keck Observatory surveyed several subgiant stars for extrasolar planets via Doppler spectroscopy They happened to find a massive Jupiter-like planet orbiting HD 212771.
HD 212771 is named Lionrock. The name was selected in the NameExoWorlds campaign by Hong Kong, during the 100th anniversary of the IAU. It is named after the Lion Rock. The planet is named Victoriapeak, after the Victoria Peak.
References
G-type subgiants
110813
Aquarius (constellation)
212771
Durchmusterung objects
Planetary systems with one confirmed planet | HD 212771 | [
"Astronomy"
] | 326 | [
"Constellations",
"Aquarius (constellation)"
] |
68,003,141 | https://en.wikipedia.org/wiki/Paired%20receptors | Paired receptors are pairs or clusters of receptor proteins that bind to extracellular ligands but have opposing activating and inhibitory signaling effects. Traditionally, paired receptors are defined as homologous pairs with similar extracellular domains and different cytoplasmic regions, whose genes are located together in the genome as part of the same gene cluster and which evolved through gene duplication. Homologous paired receptors often, but not always, have a shared ligand in common. More broadly, pairs of receptors have been identified that exhibit paired functional behavior - responding to a shared ligand with opposing intracellular signals - but are not closely homologous or co-located in the genome. Paired receptors are highly expressed in the cells of the immune system, especially natural killer (NK) and myeloid cells, and are involved in immune regulation.
Structure
Paired receptors are membrane proteins with extracellular domains that interact with extracellular ligands. The extracellular region may contain multiple repeating protein domains and may be members of either the immunoglobulin or C-type lectin families. The extracellular domains of homologous paired receptors are typically very similar in sequence but have different binding affinity for their shared ligands, with the inhibitory member of the pair binding more tightly.
Homologous paired receptors have characteristic differences in their transmembrane and cytoplasmic regions that distinguish the activating and inhibiting members of the pair. Inhibitory receptors have a cytoplasmic sequence typically containing at least one immunoreceptor tyrosine-based inhibitory motif (ITIM). Activating receptors have a truncated cytoplasmic sequence compared to their corresponding inhibitory receptor and feature a positively charged amino acid residue in their transmembrane domain, enabling protein-protein interaction with an adaptor protein that possesses a immunoreceptor tyrosine-based activation motif (ITAM).
Genetics and evolution
Homologous paired receptors are located in the same gene cluster and are thought to have evolved through gene duplication. Sequence features such as the presence of an ITIM-like sequence in the 3' untranslated region of some activating receptors imply that the activating members of the pair likely evolved from the inhibitory members. A number of pathogens interact with the inhibitory member of a pair as a means of immune evasion or viral entry, suggesting that activating members with similar binding competencies may be an evolutionary response to this mechanism. This hypothesis is known as the "counterbalance theory" and these evolutionary dynamics represent an evolutionary arms race between pathogens and the host immune system. The evolutionary pressures on some paired-receptor families have been described as examples of the "Red Queen" effect.
Including non-paired examples, over 300 potential immune inhibitory receptors have been identified in the human genome. There are strong indications that paired receptors are rapidly and recently evolving. These genetic regions have high levels of gene polymorphism, and the gene repertoires found in the genomes of closely related lineages vary significantly. The selective pressure experienced by the host from pathogens is thought to underlie this rapid evolution.
Although paired receptors are best characterized as part of the human and mouse immune systems, they have also been studied in other organisms. The chicken (Gallus gallus domesticus) genome contains a number of examples including a very large family, the chicken Ig-like receptors (CHIR) with over 100 members. Paired receptor evolution has also been studied in Xenopus (clawed frog) species. The adaptive immune system is unique to jawed vertebrates, but an example of a paired receptor family has been identified in a jawless vertebrate, termed agnathan paired receptors resembling Ag receptors (APAR) in the hagfish.
Expression
Expression of paired receptors is common in many types of leukocytes, especially myeloid cells and natural killer (NK) cells. Activation of NK cells is a complex regulatory process modulated by a number of different paired receptor families coexpressed in this cell type. In some cases, only one member of the pair is expressed in a cell type. Expression of the paired members in a single cell type may vary with time, or the proteins may differ in subcellular localization, resulting in variations in signaling. Expression in NK cells can be stochastic, resulting in unique variations in receptor repertoire.
Some paired receptors are expressed outside the immune system, for example in neurons, endothelium, and epithelium but in many examples, wide tissue distribution can be observed.
Function
Paired receptors transduce extracellular signals through opposing intracellular signaling pathways. Canonically, inhibitory receptors recruit phosphatases through their ITIM motifs, inhibiting the function of cells in which they are expressed. By contrast, activating receptors interact with adaptor proteins such as DAP-12 bearing an ITAM motif, which in turn recruit kinases such as Syk and ZAP70.
Ligands for paired receptors can be very diverse. They are often proteins; the best-characterized are the MHC class I molecules, but a number of other endogenous molecules have been described as ligands for at least one family of paired receptors, and in a few cases in the LILR family, even intact bacteria or viruses can serve as ligands. Lipids such as phosphatidylethanolamine and phosphatidylserine, sugars and sialylated glycans, and nucleic acids can all serve as ligands for some paired receptors.
The binding affinity of paired receptors' extracellular domains for their ligands is generally fairly weak, with dissociation constants (Kd) in the micromolar (μM) range. However, the inhibitory member of a pair usually binds with higher affinity than the activating member. This can produce a competitive inhibition effect, in which the inhibitory member of the pair out-competes its activating counterpart for ligand binding; other mechanisms of interference with activation, such as disrupting dimerization, have also been described. Thus the net baseline signal from the pair is usually inhibitory, but may be modulated through differences in expression, surface density, subcellular localization, or other factors.
In NK cells, ligands for inhibitory receptors are often MHC class I (MHC-I) molecules, while those for activating receptors may include signals of abnormality or infection such as proteins from pathogens or tumors, or molecules associated with cell stress. Endogenous ligands for inhibitory receptors are better characterized than those for activating receptors. Paired receptor signaling may represent maintenance of homeostasis such that immune responses to normal host cells are inhibited, while responses to abnormal or pathogenic molecules in the environment are activating. NK activation in the absence of inhibitory receptor signals from endogenous ligands is a molecular mechanism for the missing-self hypothesis of NK activation.
Interaction with pathogens
A number of examples of molecular mimicry by pathogens, emulating natural endogenous ligands of paired receptors for immune evasion, have been described in the literature. Such interactions are particularly common with the inhibitory members of receptor pairs, bolstering the hypothesis that activating partners are a later evolutionary response to this immune escape strategy.
The first described interaction between a paired receptor and a viral protein identified ILT-2 and ILR-4 (LILRB1 and LILRB2) as targets for herpes simplex virus UL18 protein, which resembles an MHC-I molecule. Variations in susceptibility to mouse cytomegalovirus infection due to differences in Ly49-family paired receptors among mouse strains are well-characterized, and are attributed to the structural resemblance between the viral protein m157 and MHC-I molecules. The pathogenic bacterium Escherichia coli K1 exposes surface polysialic acid molecules that serve as a molecular mimic for the native ligand of the inhibitory receptor Siglec-11, but induces an opposing response through interactions with the paired activating receptor Siglec-16, exemplifying the benefit of activating receptors as defense mechanisms against molecular mimicry by pathogens.
Paired receptors are also used as viral entry receptors by a number of viruses and occasionally as entry mechanisms for other pathogens. Sialylation is common among mammalian cell-surface proteins and a number of pathogens use sialic acid - either self-synthesized or obtained from the host cell - to evade host immunity, including by interacting with inhibitory siglec receptors.
Families
There are two main groups of paired receptors, distinguished by extracellular regions containing immunoglobulin or C-type lectin domains. Nomenclature within these families is complex and has changed over time as new members were identified. In general, the example of the LILR family applies; genes designated A represent the inhibitory receptor and genes designated B represent the activating receptor.
Immunoglobulin-like receptors
Immunoglobulin-like receptors are members of the immunoglobulin superfamily and have one or more 70-110 residue immunoglobulin domains (Ig) in their extracellular region, typically multiple such domains in tandem. Many of the genes encoding these proteins occur in the leukocyte receptor complex (LRC), a large gene cluster on human chromosome 19. Members of this group found in the human genome include:
The killer-cell immunoglobulin-like receptor (KIR) family contains proteins with 2-3 extracellular Ig domains and long (inhibitory) or short (activating) cytoplasmic regions. Typically expressed in NK and some T cells, they interact with MHC class I. This gene family located in the LRC is highly polymorphic and there is individual variation in both alleles and copy number, as well as in alternative splicing. This family has undergone significant diversification in primate lineages.
The leukocyte immunoglobulin-like receptors (LILR) family contains 13 genes, including two pseudogenes. They have 2-4 Ig domains. One member, LILRA3, lacks a transmembrane region and is a soluble protein; others may be expressed in soluble form through alternative splicing. Like the similar KIR family, LILR genes are found in the LRC and are polymorphic, though less so than KIR. LILR proteins are broadly expressed in immune cells and have very diverse ligands.
The paired type 2 immunoglobulin like receptor (PILR) family contains two genes, PILRA (inhibiting) and PILRB (activating). They have a single extracellular Ig domain with a siglec-like structure.
The signal regulatory protein (SIRP) family contains three genes, SIRPA (inhibiting), SIRPB1 (activating), and SIRPG (non-signaling), with the more distantly related SIRPD and SIRPB2 not yet well characterized. SIRPA interacts with CD47, a regulator of phagocytosis. This family also interacts with surfactant protein D.
The carcinoembryonic antigen-related cell adhesion (CEACAM) family contains 12 genes with one or more Ig domains. They are expressed broadly, especially in endothelium and epithelium and have roles in cell-cell recognition. They have been extensively studied for their role in cancer and have been used as cancer biomarkers.
The siglec family contains 15 genes divided into two evolutionarily related groups. This family has three members with activating motifs, Siglec-14, Siglec-15, and Siglec-16. These proteins bind sialic acids, and are often targeted by pathogens.
TIGIT (T cell immunoreceptor with Ig and ITIM domains) is an inhibitory receptor that forms a nonhomologous but functional pair with DNAM1 (CD226).
C-type lectin-like receptors
C-type lectin-like receptors (CLRs) contain one or more C-type lectin (Ca2+ dependent carbohydrate-binding lectin) domains. Example pairs include:
CD94/NKG2, expressed in NK and some T cells and interacts with the ligand HLA-E.
Dendritic cell immunoreceptor (DCIR)/dendritic cell immunoactivating receptor (DCAR), characterized as a pair in mice, though no human DCAR has been identified.
NKR-P1 (CD161) is a member of a paired receptor group in rodents, but the human genome contains only one, inhibitory receptor, NKRP1A (KLRB1).
The Ly49 family in mice has been extensively studied for its role in NK activation using laboratory mice as a model organism, but has no homologous gene cluster in the human genome. The KIR family is the functional equivalent.
References
Immune receptors
Signal transduction | Paired receptors | [
"Chemistry",
"Biology"
] | 2,691 | [
"Biochemistry",
"Neurochemistry",
"Signal transduction"
] |
68,003,371 | https://en.wikipedia.org/wiki/C/2010%20U3%20%28Boattini%29 | C/2010 U3 (Boattini) is the hyperbolic comet with the longest observation arc and took around a million years to complete half an orbit from its furthest distance in the Oort cloud. It was discovered on 31 October 2010 by Andrea Boattini in images taken with the Mount Lemmon Survey's 1.5-m reflector. The perihelion point is outside of the inner Solar System.
The comet has an observation arc of 15 years allowing a very good estimate of the inbound (original) and outbound (future) orbits. The orbit of a long-period comet is properly obtained when the osculating orbit is computed at an epoch after leaving the planetary region and is calculated with respect to the center of mass of the Solar System. Inbound JPL Horizons shows an epoch 1950 barycentric orbital period of 2.2 millions years with aphelion of from the Sun. Hui et al 2019 has a similar inbound orbital period of 2 million years. Outbound with an epoch of 2050 JPL Horizons shows a period of approximately 350,000 years and an aphelion distance of .
The generic JPL Small-Body Database browser uses a near-perihelion epoch of 2017-Jun-01 which is before the comet left the planetary region and makes the highly eccentric aphelion point inaccurate since it does not account for any planetary perturbations after that epoch. The heliocentric JPL Small-Body Database solution also does not account for the combined mass of the Sun+Jupiter.
Precovery images from November 2005 when the comet was active from the Sun are known. The comet was seen to outburst in 2009 and 2017. The coma and tail consist of dust grains about 20 μm in diameter ejected at less than . Supervolatiles such as CO and CO2 can generate activity when a comet is this far from the Sun.
References
Non-periodic comets
20101031
Oort cloud | C/2010 U3 (Boattini) | [
"Astronomy"
] | 401 | [
"Astronomical hypotheses",
"Oort cloud"
] |
68,004,323 | https://en.wikipedia.org/wiki/Calcium%20polonide | Calcium polonide is an intermetallic compound with the chemical formula . It is made up of calcium and polonium. Rather than being found in nature, the compound is entirely synthetic, and difficult to study, due to polonium's high vapor pressure, radioactivity, and easy oxidation in air.
Structure
At atmospheric pressure, it crystalizes in the cubic rock salt crystal structure. At a high pressure of around 16.7 GPa, the structure is predicted to transform to the caesium chloride-type crystal structure.
Electronic properties
Based on theoretical calculations, calcium polonide is predicted to be a semiconductor.
See also
Magnesium polonide
Potassium polonide
References
Polonides
Calcium compounds
Rock salt crystal structure | Calcium polonide | [
"Chemistry"
] | 149 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
68,004,457 | https://en.wikipedia.org/wiki/Merafloxacin | Merafloxacin is a fluoroquinolone antibacterial that inhibits the pseudoknot formation which is necessary for the frameshift in the SARS-CoV-2 genome. It is a promising drug candidate for SARS-CoV-2.
References
Beta-Amino acids
Fluoroquinolone antibiotics
COVID-19 drug development
Secondary amino acids
Pyrrolidines | Merafloxacin | [
"Chemistry"
] | 85 | [
"COVID-19 drug development",
"Drug discovery"
] |
68,005,013 | https://en.wikipedia.org/wiki/Quwivirus | Quwivirus is a genus of viruses in the subfamily Betaherpesvirinae, in the family Herpesviridae, in the order Herpesvirales.
Species
The genus consists of the following three species:
Caviid betaherpesvirus 2
Miniopterid betaherpesvirus 1
Tupaiid betaherpesvirus 1
References
Betaherpesvirinae
Virus genera | Quwivirus | [
"Biology"
] | 79 | [
"Virus stubs",
"Viruses"
] |
68,005,799 | https://en.wikipedia.org/wiki/HR%203750 | HR 3750 is a binary star system in the equatorial constellation of Hydra at a distance of 101 light years. This object is visible to the naked eye as a dim, white star with an apparent visual magnitude of 5.4. It is receding from the Earth with a heliocentric radial velocity of 57.9 km/s. This binary is unusual because its eruptions do not seem to conform to the Waldmeier effect—i.e. the strongest eruptions of HR 3750 are not the ones characterized by the fast eruption onset. Kinematically, the binary belongs to the thick disk of the Milky Way galaxy - a population of ancient, metal-poor stars.
The star system is a spectroscopic binary with a 32 year, nearly edge-on orbit. The primary, HD 81809 A's visual magnitude is 5.610 while the secondary, HD 81809 B's visual magnitude is 7.115 The larger star, HD 81809 A, is unusually inflated for its age and composition, possibly due to engulfment of a 0.36 red dwarf star 1-3 billion years ago.
HD 81809 A has a well defined chromospheric activity cycle with a period of 7.3 years.
References
G-type main-sequence stars
G-type subgiants
Binary stars
Hydra (constellation)
BD-05 2802
0344
81809
046404
3750
J09274680-0604164 | HR 3750 | [
"Astronomy"
] | 305 | [
"Hydra (constellation)",
"Constellations"
] |
68,005,861 | https://en.wikipedia.org/wiki/Laguna%20Negra%20virus | Laguna Negra virus (LANV) is a virus in the genus Orthohantavirus.
References
Hantaviridae | Laguna Negra virus | [
"Biology"
] | 27 | [
"Virus stubs",
"Viruses"
] |
68,006,061 | https://en.wikipedia.org/wiki/Cybersecurity%20Capacity%20Maturity%20Model%20for%20Nations | Cybersecurity Capacity Maturity Model for Nations (CMM) is a framework developed to review the cybersecurity capacity maturity of a country across five dimensions. The five dimensions covers the capacity area required by a country to improve its cybersecurity posture. It was designed by Global Cyber Security Capacity Centre (GCSCC) of University of Oxford and first of its kind framework for countries to review their cybersecurity capacity, benchmark it and receive recommendation for improvement. Each dimension is divided into factors and the factors broken down into aspects. The review process includes rating each factor or aspect along five stages that represents the how well a country is doing in respect to that factor or aspect. The recommendations includes guidance on areas of cybersecurity that needs improvement and thus will require more focus and investment. As at June, 2021, the framework has been adopted and implemented in over 80 countries worldwide. Its deployment has been catalyzed by the involvement of international organizations such as the Organization of American States (OAS), the World Bank (WB), the International Telecommunication Union (ITU) and the Commonwealth Telecommunications Union (CTO) and Global Forum on Cyber Expertise (GFCE).
Overview
The World Summit on Information Society identified capacity building in the realm of cybersecurity as one of the pillars necessary to reap the benefits of processes and services digitalization, especially in developing nations. The International Telecommunication Union reported that developing nations lack the necessary cybersecurity capacity to manage ICT risk and respond to cyberthreats. Because cyberattacks and vulnerabilities in one nation can affect other parts of the world, some maturity models were developed to assess the cybersecurity capacity of nations and benchmark the capacity level. One of such models is the CMM.
The CMM was developed in 2014, through collaborative effort between the GCSCC and over 200 experts from academia, international and regional organizations and the private sector. CMM assesses the capacity of a country from five identified area called dimensions with the objective of improving the coverage, measurement and effectiveness of cyber security capacity building within five levels of progression. Benchmarking of a country's cybersecurity capacity involves reviewing its initiatives and activities against the entire CMM and across all Dimensions. According to the report of a regional CMM assessment of Latin America and the Caribbean, CMM assessment aims to identify cybersecurity gaps and discover actions that works.
Since 2014, the CMM has undergone revisions and it is intended to be a living model that remain relevant to every aspect of cybersecurity needs at the national level.
Structure
The framework consists of dimensions, factors, aspects, indicators and stages.
Dimension.
The dimensions represent the scope of a country's cybersecurity capacity that will be assessed by CMM and it is broken down into factors. The dimensions are not stand alone, rather they are related to one another because a nation's performance in one dimension of capacity may require input from another dimension.
The five dimensions from the 2021 version are:
Developing cybersecurity policy and strategy - This dimension examines how a nation fares in terms of availability and implementation of Cybersecurity policies and strategy.
Encouraging responsible cybersecurity culture within society - This dimension views how well citizens of a nation are familiar with digital risk and the provision of a viable channel for reporting cybercriminal activities.
Building cybersecurity knowledge and capabilities - This dimension explores structures in place for cybersecurity awareness and education within the nation.
Creating effective legal and regulatory frameworks - Examine the ability of a country to develop, ratify and enforce cybersecurity and privacy related legislation.
Controlling risks through standards and technologies - This dimension examines the common use of cybersecurity standard and presence of structures for development of such technologies.
Factors:
The factors are the important component of a country's capacity whose maturity level is measured and there are 23 factors in the latest version with each having one or more aspects.
Aspects:
These are smaller subdivision of factors which helps with understanding each factor and help in evidence gathering and measurement.
Indicators:
Each Indicator define the actions that suggest that a nation has maintain a specific stage of maturity. The level of maturity assigned to an aspect depend on the ability of a nation to fulfill the steps and actions listed as its indicator. Evidence will be required to be provided before a particular stage can be attained. It is either an
evidence is available or not and to move to a higher stage, all of the Indicators within a particular stage will need to have been fulfilled.
Stage:
This represent how matured a nations is on each factor or aspect. There are 5 stages of maturity; start-up, formative, established, strategic and dynamic. For a nation to met a particular maturity stage, it has to fulfill some indicators.
Start-up - At this stage, a nation has no presentable evidence to show existence of cybersecurity initiatives.
Formative - Evidence is available to proof initiatives on some of the aspects, however these efforts may be at the initiation state or be ad hoc.
Established - The is evidence to show that the aspect is defined, functional and working but adequate resource allocation is lacking.
Strategic - Aspect has been prioritized based on national need.
Dynamic - A working adaptable cybersecurity strategy is available, which is evidenced by global leadership on cybersecurity issues, agility of decision-making, and resources allocation.
Development
The first version of the framework was released in 2014. Based on pilot assessments conducted in six countries, improvements were made on the model and an updated version was published in 2017. Based on lessons learnt over the years from CMM deployments and consultations from GCSCC Expert Advisory Panel, strategic, regional and implementation partners of the GCSCC, and other experts from academia, international and regional organisations, governments, the private sector, and civil society, an updated version was released in 2021.
The dimensions, factors and aspects have changed overtime between CMM versions.
The 2014 has 5 dimensions and 21 factors. The 2017 version has 5 dimensions with 24 factors. The 2021 version has 5 dimensions and 23 factors.
Table 1 lists the dimensions across the three versions.
Table 2 list the factors for each version.
The Review Process
CMM review process has 3 stages.
Stage 1: Desk research and country-partner identification.
The first step is selection of a country. A CMM review can be requested by a country or a country can be selected for assessment by an international or regional organization.
Once a nation is selected for assessment, a relationship is established with the host country and necessary stakeholders identified from academia, civil societies, government ministries/department, international organizations and the private sector.
Stage 2: The Review
The actual review with the stakeholders is a three-day consultation process and based on the five dimensions, multiple teams are created across stakeholders.
Open discussions or focus groups method is applied to ask and answers questions. Questions and answer can also be collected using online tool. Inability to provide evidence for all indicators under each aspect will result in a lower maturity level for that aspect.
Remote follow-up sessions or email communication may be used for further data collection.
Stage 3: Review Report
A report is presented to the country's government and it is at the discretion of that country to make it publicly available or not.
The recommendation
The output of the CMM assessment is a report which details the gaps identified from each aspect and the present maturity level of each indicator. The assessment report is the property of the assessed nation and they choose whether to make it public or not. Depending on a nation's need, it recommend areas that should be given priority in terms of resource allocation.
The report include a sunburst representation of the cybersecurity capacity of the nation, reason for placing each factor or aspect in a particular stage and recommendation of what can be done to move up along the maturity stage.
Sample results from some of the reviews are available on GCSCC's website.
Nations with CMM Assessment
The GCSCC website has the list of nations that has been assessed, which have been listed below.
Albania
Antigua and Barbuda
Argentina
Armenia
Bahamas
Bangladesh
Barbados
Belize
Benin
Bhutan
Bolivia
Bosnia and Herzegovina
Botswana
Brazil
Burkina Faso
Cabo Verde
Cameroon
Chile
Colombia
Cook Islands
Costa Rica
Cyprus
Dominica
Dominican Republic
Ecuador
El Salvador
Eswatini
Fiji
Gambia
Georgia
Ghana
Grenada
Guatemala
Guyana
Haiti
Honduras
Iceland
Indonesia
Ivory Coast
Jamaica
Kiribati
Kosovo
Kyrgyzstan
Lesotho
Liberia
Lithuania
Madagascar
Malawi
Mauritius
Mexico
Micronesia
Montenegro
Morocco
Mozambique
Myanmar
Namibia
Nicaragua
Niger
Nigeria
North Macedonia
Panama
Papua New Guinea
Paraguay
Peru
Rwanda
Saint Kitts and Nevis
Saint Lucia
Saint Vincent and the Grenadines
Samoa
Senegal
Serbia
Sierra Leone
Somalia
Sri Lanka
Suriname
Switzerland
Tanzania
Thailand
Tonga
Trinidad and Tobago
Tunisia
Tuvalu
Uganda
United Kingdom
Uruguay
Vanuatu
Venezuela
Zambia
References
Cyberspace
Computer security exploits | Cybersecurity Capacity Maturity Model for Nations | [
"Technology"
] | 1,790 | [
"Information technology",
"Computer security exploits",
"Cyberspace"
] |
63,684,924 | https://en.wikipedia.org/wiki/Pneumonia%20of%20unknown%20etiology%20%28PUE%29%20surveillance%20system | The pneumonia of unknown etiology (PUE) surveillance system is a Chinese monitoring system, established in response to the 2002–2004 SARS outbreak to track emerging respiratory infections, including avian flu and SARS. On 29 December 2019, local hospitals in Wuhan, Hubei Province, China, identified four closely related people, linked to a local wet market, as having a “pneumonia of unknown etiology” using the national system. Their illness was later confirmed as COVID-19 due to SARS-CoV-2.
References
Health informatics
COVID-19 pandemic in China | Pneumonia of unknown etiology (PUE) surveillance system | [
"Biology"
] | 123 | [
"Health informatics",
"Medical technology"
] |
63,685,328 | https://en.wikipedia.org/wiki/Yanliao%20Biota | The Yanliao Biota is the name given to an assembly of fossils preserved in northeastern China from the Middle to Late Jurassic. It includes fossils from the Tiaojishan Formation and Haifanggou Formation. This spans approximately 165 to 150 million years ago.
Like the Jehol Biota, these deposits are composed of alternating layers of volcanic tuff and sediment, and are considered Lagerstätte. These are some of the best preserved Jurassic fossils in the world, and include many important dinosaur, mammal, salamander, insect and lizard specimens, as well as plants.
History
The first fossils of the Yanliao Biota were found around 1998 near the village of Daohugou in Inner Mongolia. The following year, the first two important specimens were discovered, and published in 2000. Since that time many more have been found from the same area, and in neighbouring provinces.
The Yanliao Biota is made up of fossils from more than one locality, and the geology has been difficult to interpret (see below). It includes what was previously referred to as the Daohugou Biota, and some of it was thought to belong to the Jehol Biota.
Location
The Yanliao Biota comes from outcrops north of the Han Mountains, in the northeast of the People's Republic of China. The most important site is near Daohugou Village in Inner Mongolia, but fossils and outcrops are also found in neighbouring Liaoning Province and Heibei Province.
Geology
The Dauhugou locality lies in the Ningchen Basin in the SE corner of Inner Mongolia. Dauhugou village has fossil-bearing lacustrine (laid down in lakes) strata overlying precambrian basement.
Fossil preservation
The formations that yield the fossils of the Yanliao Biota are known as Lagerstätte, meaning that they have exceptionally good conditions for fossil preservation. The fossils are not only numerous, but also very well preserved. For vertebrates, there are often whole skeletons with soft tissues like skin and fur, colour patterns, and stomach contents. Insects are intact with wings and patterns preserved, and plants have their leaves and flowers still attached. The volcanic ash layers quickly buried the organisms, and created an anoxic environment around them, preventing scavenging and helping preserve them.
Fossils
Dinosaurs
Anchiornis huxleyi
Epidendrosaurus ningchengensis
Epidexipteryx hui
Pedopenna daohugouensis
Xiaotingia zhengi
Aurornis xui
Eosinopteryx brevipenna
Caihong juji
Tianyulong confuciusi
Scansoriopteryx heilmanni
Yi qi
Serikornis sungei
Pterosaurs
Jeholopterus ningchengensis
Archaeoistiodactylus linglongtaensis (possibly Darwinopterus; Martill and Etches, 2012)
Changchengopterus
Darwinopterus modularis
Darwinopterus linglongtaensis
Darwinopterus robustodens
Jianchangnathus robustus
Jianchangopterus zhaoianus
Fenghuangopterus lii
Kunpengopterus sinensis
Wukongopterus lii
Changchengopterus pani
Dendrorhynchoides mutoudengensis
Qinglongopterus guoi
Pterorhynchus wellnhoferi
Cascocauda rong
Sinomacrops bondei
Mammaliaforms
Castorocauda lutrasimilis
Volaticotherium antiquum
Arboroharamiya jenkinsi
Juramaia sinensis
Maiopatagium furculiferum
Vilevolodon diplomylos
Agilodocodon gracilis
Megaconus mammaliaformis
Docofossor brachydactylus
Microdocodon gracilis
Rugosodon eurasiaticus
Mirusodens caii
Caudates
Beiyanerpeton jianpingensis
Chunerpeton tianyiensis
Jeholotriton paradoxus
Neimengtriton daohugouensis
Pangerpeton sinensis
See also
Daohugou Biota
References
Geology of China
Natural history of China
Geography of Liaoning
Geography of Hebei
Geography of Inner Mongolia
Geography of Northeast Asia
Geologic formations of China
Paleontology in Liaoning
Paleontology in Hebei
Mesozoic paleobiotas | Yanliao Biota | [
"Biology"
] | 890 | [
"Mesozoic paleobiotas",
"Prehistoric biotas"
] |
63,686,596 | https://en.wikipedia.org/wiki/Pipe%20plug | A pipe plug is a tool or material for the temporary sealing of pipelines in sewerage and other liquid and gas transportation systems; typically for maintenance or non-pressurized line testing. A pipe plug is also known as an inflatable plug, mechanical pipe plug, pipe test plug, pipeline isolation plug, expandable plug, pipe bung, pipe stopper, pipe packer, pneumatic pipe plug or pipe balloon depending on the region where it is used.
History
The origin is debated, but the earliest patents related with plugging the pipes date back to the 1890s. The first patent for a pipe plug as we know today is by Oscar F. Anderson, published in 1952., and the first patent for inflatable plugs was published in 1965
Usage
Pipe plugs are often confused with relatively smaller plumbing accessories. However, as an industrial tool, pipe plugs are used in larger infrastructure pipelines. Pipe plugs provide a trench-less method for the maintenance of drains and sewers, and construction and testing of non-pressurized gravity pipelines.
There are three main purposes of pipe plugs. These are temporary sealing or stopping the fluid flow in a pipeline, leak testing and by-passing the flow. They are also used for blocking the ends of pipes to prevent the entry of dirt and other contaminants during construction, maintenance or repair of pipelines.
The leak tests of gravity pipelines using the pipe plug are performed with respecting the requirements of the European Standard EN1610 for both water and air tests.
The inflatable pipe plugs have a wide variety of types each for different purpose:
Pipe plug
Pipe test plug
Conical plug
Pipe packer
High pressure pipe plug
Oil and gas pipe plug
Steam process plug
Pipe joint tester
Back pressure
Back pressure is a major issue for the users of pipe plugs on site. It refers to the force that a pipe plug holds during the process. Pipe plugs are usually subject to huge amount of back pressure that occurs in the pipeline, so the back pressure must be calculated accurately in order to prevent the pipe plug to slip inside the pipe. Slipping of the pipe plug may cause in hazardous results. Though Mechanical and Inflatable Pipe Plugs can rely upon the seals for restraint, typically, secondary mechanical restraint is required to prevent slippage – in the form of friction screw dogs that engage to the pipe, by utilizing strong back supports, anchors, or other user added blocking methods.
Formula of back pressure calculation
Accessories
Pipe plugs are used with supplementary accessories such as air and water hoses, air and pressure control devices, gauges, adapters and chains depending on the type of the pipe plug and the process.
Auxiliary equipment like compressors for inflating the pipe plugs, water tanks for filling the pipeline and pumps for some cases must be used.
Maintenance
For a longer life cycle, pipe plugs should be cleaned with soap and water before and after each use. Chemical solvents, hydrocarbons, petroleum fluids or other aggressive substances shouldn't be used while cleaning, since they may damage or destroy the rubber of the pipe plug. After cleaning, pipe plugs should be flushed with clean water and left to dry at room temperature before using in the pipelines.
Storing conditions are determined by the ISO 2230 standard. Pipe plugs are to be stored in a dry space at 15-25 °C away from direct sun light and circulating air. Long term contact with liquids, metals and other rubber materials should be avoided.
References
External links
BS EN 1610:2015 Construction and testing of drains and sewers
Oscar F Anderson
Pneumatic
Plumbing | Pipe plug | [
"Engineering"
] | 730 | [
"Construction",
"Plumbing"
] |
63,687,701 | https://en.wikipedia.org/wiki/C/2020%20F5%20%28MASTER%29 | C/2020 F5 (MASTER) is a non-periodic comet discovered on 28 March 2020, by the MASTER auto-detection system near San Juan, Argentina.
When first discovered there were dubious claims that it might be an interstellar object, but now it is known to have a common weakly hyperbolic eccentricity of just 1.0007. Before planetary perturbations the comet had an orbital period of about 36000 years.
References
External links
Non-periodic comets
Astronomical objects discovered in 2020
Comets in 2020 | C/2020 F5 (MASTER) | [
"Astronomy"
] | 105 | [
"Astronomy stubs",
"Comet stubs"
] |
63,687,736 | https://en.wikipedia.org/wiki/Embelin | Embelin (2,5-dihydroxy-3-undecyl-1,4-benzoquinone) is a naturally occurring para-benzoquinone isolated from dried berries of Embelia ribes plants. Several studies have reported antidiabetic activity of embelin.
References
Antioxidants
Anti-aging substances
1,4-Benzoquinones
Hydroquinones | Embelin | [
"Chemistry",
"Biology"
] | 86 | [
"Senescence",
"Anti-aging substances"
] |
63,687,773 | https://en.wikipedia.org/wiki/Age%20management%20medicine | Longevity medicine is a set of preventive healthcare practices that rely on biomarkers of aging, such as aging clocks, to keep the patient's biological and psychological age as near to peak performance as feasible throughout life. Biogerontology and precision medicine are some of the related fields. As of early 2020s it is a "fast developing field", according to an article in a Lancet specialty journal.
In the first decade of the 21st century, what was called "age management medicine" was considered a field of alternative medicine, and, as of 2007, was not recognized by the American Medical Association. Other names at this time included "antiaging medicine" and "regenerative medicine". Age management medicine is controversial. The field is underregulated and supported by insufficient scientific evidence. People who practice it open themselves up to legal liability on grounds of negligence–malpractice, warranty issues, and product liability. The use of growth hormone has been frequently recommended; however, such use is associated with cancer.
Age management medicine is often promoted by anti-aging practitioners specializing in nutritional supplements and hormone-replacement, a practice that may lead to harmful side-effects.
See also
Life extension
Anti-aging movement
References
Life extension
Medical treatments
Medical controversies
Ageing
Population
Anti-aging substances
Transhumanism | Age management medicine | [
"Chemistry",
"Technology",
"Engineering",
"Biology"
] | 268 | [
"Anti-aging substances",
"Genetic engineering",
"Transhumanism",
"Senescence",
"Ethics of science and technology"
] |
63,687,776 | https://en.wikipedia.org/wiki/NGC%203008 | NGC 3008 is a lenticular galaxy with an active galactic nucleus in the constellation of Ursa Major, discovered by William Parsons and his assistants. It is about 40 thousand light years across, and with a recessional velocity of about 4,785 kilometers per second, is at a distance of 240 million light-years from the Sun.
It is a member of the NGC 2998 group, which also includes NGC 2998, NGC 3002, NGC 3005, NGC 3006, and a few others. Among these galaxies, it has the lowest star formation rate, at per year.
References
External links
Lenticular galaxies
3008
Ursa Major
028252 | NGC 3008 | [
"Astronomy"
] | 136 | [
"Ursa Major",
"Constellations"
] |
63,687,901 | https://en.wikipedia.org/wiki/Thermogravitational%20cycle | A thermogravitational cycle is a reversible thermodynamic cycle using the gravitational works of weight and buoyancy to respectively compress and expand a working fluid.
Theoretical framework
Consider a column filled with a transporting medium and a balloon filled with a working fluid. Due to the hydrostatic pressure of the transporting medium, the pressure inside the column increases along the z axis (see figure). Initially, the balloon is inflated by the working fluid at temperature TC and pressure P0 and located on top of the column. A thermogravitational cycle is decomposed into four ideal steps:
1→2: Descent of the balloon towards the bottom of the column. The working fluid undergoes adiabatic compression with its temperature increasing and its pressure reaching value Ph at the bottom (Ph>P0).
2→3: While the ballon lays at the bottom, the working fluid receives heat from the hot source at temperature TH and undergoes isobaric expansion at pressure Ph.
3→4: The balloon rises towards the column top. The working fluid undergoes adiabatic expansion with a drop in temperature and reaches pressure P0 after expansion when the balloon is on top.
4→1: Once arrived on top, the working fluid supplies heat to the cold source at temperature TC while undergoing isobaric compression at pressure P0.
For a thermogravitational cycle to occur, the balloon has to be denser than the transporting medium during 1→2 step and less dense during 3→4 step. If these conditions are not naturally satisfied by the working fluid, a weight can be attached to the balloon to increase its effective mass density.
Applications and examples
An experimental device working according to thermogravitational cycle principle was developed in a laboratory of the University of Bordeaux and patented in France. Such thermogravitational electric generator is based on inflation and deflation cycles of an elastic bag made of nitrile elastomer cut from a glove finger. The bag is filled with a volatile working fluid that has low chemical affinity for the elastomer such as perfluorohexane (C6F14). It is attached to a strong NdFeB spherical magnet that acts both as a weight and for transducing the mechanical energy into voltage. The glass cylinder is filled with water acting as transporting fluid. It is heated at the bottom by a hot circulating water-jacket, and cooled down at the top by a cold water bath. Due to its low boiling point temperature (56 °C), the perfluorohexane drop contained in the bag vaporizes and inflates the balloon. Once its density is lower than the water density, the balloon raises according to Archimedes’ principle. Cooled down at the column top, the balloon deflates partially until its gets effectively denser than water and starts to fall down. As seen from the videos, the cyclic motion has a period of several seconds. These oscillations can last for several hours and their duration is limited only by leaks of the working fluid through the rubbery membrane. Each time the magnet goes through the coil produces a variation in the magnetic flux. An electromotive force is created and detected through an oscilloscope. It has been estimated that the average power of this machine is 7 μW and its efficiency is 4.8 x 10−6. Although these values are very small, this experiment brings a proof of principle of renewable energy device for harvesting electricity from a weak waste heat source without need of other external energy supply, e.g. for a compressor in a regular heat engine. The experiment was successfully reproduced by undergraduate students in preparatory classes of the Lycée Hoche in Versailles.
Several other applications based on the thermogravitational cycles could be found in the literature. For example:
In solar balloons, heat from the sun is absorbed which causes a balloon filled with air to rise and convert its movement in an electric signal.
In a gravity driven organic Rankine cycle, gravity is used instead of a pump to pressurize a working fluid. In literature, different authors have studied the working fluid characteristics best suited to optimize their efficiency for gravity-driven ORC devices.
In a version of a magnetic fluid generator, a refrigerant fluid is vaporized at the bottom of a column by an external heat source, and its bubbles move across a magnetized ferrofluid, thereby producing electric voltage via a linear generator.
In a conceptual hybrid of several patents, solar or geothermal energy is harnessed by means of a modified organic Rankine cycle with high columns of water below ground
Cycle efficiency
The efficiency η of a thermogravitational cycle depends on the thermodynamic processes the working fluid goes through during each step of the cycle. Below some examples:
If the heat exchanges at the bottom and top of the column with a hot source and cold source respectively, occur at constant pressure and temperature, the efficiency would be equal to the efficiency of a Carnot cycle:
If the working fluid stays at the liquid stage during the compression stage 1→2, the efficiency would be equal to the Rankine cycle efficiency. By noting h1, h2, h3 and h4 the specific enthalpies of the working fluid at stages 1,2,3 and 4 respectively:
If the working fluid remains a gas during all the steps of a thermogravitational cycle, the efficiency would be equal to the Brayton cycle efficiency. By noting γ the heat capacity ratio:
References
Thermodynamic cycles
Equilibrium chemistry
Thermodynamic processes
Thermodynamic systems | Thermogravitational cycle | [
"Physics",
"Chemistry",
"Mathematics"
] | 1,163 | [
"Thermodynamic systems",
"Thermodynamic processes",
"Physical systems",
"Equilibrium chemistry",
"Thermodynamics",
"Dynamical systems"
] |
63,688,300 | https://en.wikipedia.org/wiki/NGC%203009 | NGC 3009 is a lenticular galaxy in the constellation of Ursa Major. It is about 35 thousand light years across, and with a recessional velocity of 4,445 kilometers per second, is at a distance of 205 million light years from the sun. NGC 3009 is also known by the catalog name of PGC 28330, and is often mistaken for the dimmer PGC 28303. This is because these objects are very close to each other in the sky, and the astronomer Dreyer misinterpreted John Herschel's original March 17, 1828 record of the galaxy, mistaking it for one a few arcminutes to the west (which is now known as PGC 28303). Herschel would have been unable to see PGC 28303 as anything but a background star, due to his less advanced telescope at the time.
References
Lenticular galaxies
Ursa Major
3009
028303 | NGC 3009 | [
"Astronomy"
] | 195 | [
"Ursa Major",
"Constellations"
] |
63,688,717 | https://en.wikipedia.org/wiki/Ptak%20space | A locally convex topological vector space (TVS) is B-complete or a Ptak space if every subspace is closed in the weak-* topology on (i.e. or ) whenever is closed in (when is given the subspace topology from ) for each equicontinuous subset .
B-completeness is related to -completeness, where a locally convex TVS is -complete if every subspace is closed in whenever is closed in (when is given the subspace topology from ) for each equicontinuous subset .
Characterizations
Throughout this section, will be a locally convex topological vector space (TVS).
The following are equivalent:
is a Ptak space.
Every continuous nearly open linear map of into any locally convex space is a topological homomorphism.
A linear map is called nearly open if for each neighborhood of the origin in , is dense in some neighborhood of the origin in
The following are equivalent:
is -complete.
Every continuous biunivocal, nearly open linear map of into any locally convex space is a TVS-isomorphism.
Properties
Every Ptak space is complete. However, there exist complete Hausdorff locally convex space that are not Ptak spaces.
Let be a nearly open linear map whose domain is dense in a -complete space and whose range is a locally convex space . Suppose that the graph of is closed in . If is injective or if is a Ptak space then is an open map.
Examples and sufficient conditions
There exist Br-complete spaces that are not B-complete.
Every Fréchet space is a Ptak space. The strong dual of a reflexive Fréchet space is a Ptak space.
Every closed vector subspace of a Ptak space (resp. a Br-complete space) is a Ptak space (resp. a -complete space). and every Hausdorff quotient of a Ptak space is a Ptak space.
If every Hausdorff quotient of a TVS is a Br-complete space then is a B-complete space.
If is a locally convex space such that there exists a continuous nearly open surjection from a Ptak space, then is a Ptak space.
If a TVS has a closed hyperplane that is B-complete (resp. Br-complete) then is B-complete (resp. Br-complete).
See also
Notes
References
Bibliography
External links
Nuclear space at ncatlab
Topological vector spaces | Ptak space | [
"Mathematics"
] | 506 | [
"Topological vector spaces",
"Vector spaces",
"Space (mathematics)"
] |
63,688,957 | https://en.wikipedia.org/wiki/Integral%20linear%20operator | In mathematical analysis, an integral linear operator is a linear operator T given by integration; i.e.,
where is called an integration kernel.
More generally, an integral bilinear form is a bilinear functional that belongs to the continuous dual space of , the injective tensor product of the locally convex topological vector spaces (TVSs) X and Y. An integral linear operator is a continuous linear operator that arises in a canonical way from an integral bilinear form.
These maps play an important role in the theory of nuclear spaces and nuclear maps.
Definition - Integral forms as the dual of the injective tensor product
Let X and Y be locally convex TVSs, let denote the projective tensor product, denote its completion, let denote the injective tensor product, and denote its completion.
Suppose that denotes the TVS-embedding of into its completion and let be its transpose, which is a vector space-isomorphism. This identifies the continuous dual space of as being identical to the continuous dual space of .
Let denote the identity map and denote its transpose, which is a continuous injection. Recall that is canonically identified with , the space of continuous bilinear maps on . In this way, the continuous dual space of can be canonically identified as a vector subspace of , denoted by . The elements of are called integral (bilinear) forms on . The following theorem justifies the word integral.
There is also a closely related formulation of the theorem above that can also be used to explain the terminology integral bilinear form: a continuous bilinear form on the product of locally convex spaces is integral if and only if there is a compact topological space equipped with a (necessarily bounded) positive Radon measure and continuous linear maps and from and to the Banach space such that
,
i.e., the form can be realised by integrating (essentially bounded) functions on a compact space.
Integral linear maps
A continuous linear map is called integral if its associated bilinear form is an integral bilinear form, where this form is defined by . It follows that an integral map is of the form:
for suitable weakly closed and equicontinuous subsets S and T of and , respectively, and some positive Radon measure of total mass ≤ 1.
The above integral is the weak integral, so the equality holds if and only if for every , .
Given a linear map , one can define a canonical bilinear form , called the associated bilinear form on , by .
A continuous map is called integral if its associated bilinear form is an integral bilinear form. An integral map is of the form, for every and :
for suitable weakly closed and equicontinuous aubsets and of and , respectively, and some positive Radon measure of total mass .
Relation to Hilbert spaces
The following result shows that integral maps "factor through" Hilbert spaces.
Proposition: Suppose that is an integral map between locally convex TVS with Y Hausdorff and complete. There exists a Hilbert space H and two continuous linear mappings and such that .
Furthermore, every integral operator between two Hilbert spaces is nuclear. Thus a continuous linear operator between two Hilbert spaces is nuclear if and only if it is integral.
Sufficient conditions
Every nuclear map is integral. An important partial converse is that every integral operator between two Hilbert spaces is nuclear.
Suppose that A, B, C, and D are Hausdorff locally convex TVSs and that , , and are all continuous linear operators. If is an integral operator then so is the composition .
If is a continuous linear operator between two normed space then is integral if and only if is integral.
Suppose that is a continuous linear map between locally convex TVSs.
If is integral then so is its transpose . Now suppose that the transpose of the continuous linear map is integral. Then is integral if the canonical injections (defined by value at ) and are TVS-embeddings (which happens if, for instance, and are barreled or metrizable).
Properties
Suppose that A, B, C, and D are Hausdorff locally convex TVSs with B and D complete. If , , and are all integral linear maps then their composition is nuclear.
Thus, in particular, if is an infinite-dimensional Fréchet space then a continuous linear surjection cannot be an integral operator.
See also
Auxiliary normed spaces
Final topology
Injective tensor product
Nuclear operators
Nuclear spaces
Projective tensor product
Topological tensor product
References
Bibliography
External links
Nuclear space at ncatlab
Topological vector spaces
Topological tensor products
Linear operators | Integral linear operator | [
"Mathematics",
"Engineering"
] | 933 | [
"Functions and mappings",
"Tensors",
"Vector spaces",
"Mathematical objects",
"Linear operators",
"Space (mathematics)",
"Topological vector spaces",
"Mathematical relations",
"Topological tensor products"
] |
63,689,434 | https://en.wikipedia.org/wiki/Nakamichi%20Dragon | The Nakamichi Dragon is an audio cassette deck that was introduced by Nakamichi in 1982 and marketed until 1994. The Dragon was the first Nakamichi model with bidirectional replay capability and the world's first production tape recorder with an automatic azimuth correction system; this feature, which was invented by Philips engineers and improved by Niro Nakamichi, continuously adjusts the azimuth of the replay head to minimize apparent head skew and correctly reproduce the treble signal present on the tape. The system allows the correct reproduction of mechanically skewed cassettes and recordings made on misaligned decks. Apart from the Dragon, similar systems have only been used in the Nakamichi TD-1200 car cassette player and the Marantz SD-930 cassette deck.
At the time of its introduction, the Dragon had the lowest-ever wow and flutter and the highest-ever dynamic range, losing marginally to the former Nakamichi flagship the 1000ZXL in frequency response. Competing models by Sony, Studer, Tandberg and TEAC that were introduced later in the 1980s sometimes surpassed the Dragon in mechanical quality and feature set but none could deliver the same mix of sound quality, flexibility and technological advancement. The Dragon, despite inherent issues with long-term reliability, remained the highest point of compact cassette technology.
Development and production
Background
Philips introduced the Compact Cassette in 1963. The new format was intended primarily for dictation and had inherent flaws – a low tape speed and narrow track width – that precluded direct competition with vinyl records and reel-to-reel tapes. The cassette shell was designed to accommodate only two heads, ruling out the use of dedicated recording and replay heads and off-tape monitoring that were the norm in reel-to-reel recorders. In 1972, however, Nakamichi introduced a cassette deck that outperformed most domestic and semi-professional reel-to-reel recorders. Ordinary cassette decks of that period struggled to reproduce 12 kHz on ferric tape and 14 kHz on chromium dioxide tape; the Nakamichi 1000 could record and reproduce signals up to 20 kHz on tapes of either type. It was the first three-head cassette deck, the first with discrete (mechanically, magnetically and electrically separate) record and replay heads, closed-loop double capstan drive, off-tape monitoring, calibration of recording levels and bias, and a convenient manual adjustment of replay head azimuth.
While its competitors struggled to approach the performance of the 1000, Nakamichi continued research and in 1981 presented their next flagship, the 1000ZXL. The new deck has a slightly narrower dynamic range and slightly higher wow and flutter than some competitors, but exceeded them in frequency response and low recording distortion, and was praised for subjective musicality. Its price of was too high for the consumer market; the uprated "gold" version, which was priced at $6,000, became the most expensive cassette deck in history. This was a halo model, a vehicle for selling the company's numerous less expensive decks. Although Nakamichi released several models with experimental functionality, overall the company's approach to design was conservative. All models below the 1000 and 700 series followed the same general design and used the same dual-capstan transport that was introduced in 1978. Nakamichi consistently refrained from copying its competitors' latest solutions and features, refused to employ adaptive biasing and Dolby S, and did not make autoreversing decks until introduction of the Dragon. Autoreversing was desirable but bidirectional autoreversing tape transports of the 1970s suffered from inherent head azimuth instability, which caused irrecoverable treble roll-off. This issue had to be resolved before attempting to build a true high fidelity autoreversing deck.
Azimuth problem
In magnetic recording, "azimuth" denotes the orientation of the magnetic head gap – a narrow, vertical slit that spans the height of the track – with respect to the direction of tape travel. "Absolute azimuth", the angle between the gap and the direction of tape travel, must be set at precisely ninety degrees for correct replay of treble signals. In practice, the main goal is perfecting the "relative azimuth" – the angle between the recording and replay magnetic gaps, which must be as low as possible. A two-head deck, in theory, has zero relative azimuth at a given point in time but in the long term its absolute azimuth drifts away from ninety degrees. The advantage disappears when a two-head deck replays tapes recorded on equipment with an unknown absolute azimuth error.
Azimuth errors, or tape skew, affect cassette decks much more than reel-to-reel tape recorders running at higher speeds. A cassette deck claiming a frequency response up to 20 kHz must have an azimuth error less than 6' (arc minutes). Above this threshold, losses in high-frequency response steeply rise; at 20' the head is practically unable to reproduce any treble. These losses cannot be recovered with conventional analog filters. Another inherent drawback of cassettes is the instability of tape positioning relative to the mechanism. The direction of tape travel often deviates from the deck's plane of reference. Sometimes a cassette will play acceptably in one direction but not the other; sometimes azimuth error will audibly vary as the tape plays. Mechanical improvements in tape transport cannot remedy this problem because it stems from minor defects and wear of the cassette shell.
Bidirectional autoreversing cassette tape transports are particularly prone to azimuth errors. Simple transports that use fixed four-track replay heads – the industry standard for car and personal stereos – can be properly aligned in one direction only, leaving the other direction vulnerable to unpredictable random errors. Transports that use rotating two-head assemblies were usually equipped with independent alignment screws for forward and reverse directions. Rotation, however, subjects heads to mechanical stresses that quickly cause audible azimuth errors. Rotating assemblies cannot physically fit separate recording and replay heads; this drawback limits fidelity and rules out tape-source monitoring and tape calibration functionality. The third, more flexible alternative is unidirectional transports that reverse tapes by physically flipping the cassette. Philips and Akai tested this approach in the early 1970s and it was abandoned until the introduction of Nakamichi UDAR (Unidirectional Auto Reverse) decks in 1984.
Search for solution
In 1976, John Jenkins of International Tapetronics invented a novel azimuth correction system for multitrack studio recorders. Two outermost tracks of the Jenkins recorder were reserved for the reference sine wave signal. With properly aligned heads, two sine waves recorded in phase should also replay in phase. If the replay head is skewed, the output sine waves will differ in phase. A DC motor governed by a servo regulator continuously adjusts the azimuth of the replay head to minimize the difference between two signals. Thus, claimed Jenkins, his recorder was able to compensate for replay azimuth skew of any nature.
In 1978, Albert Rijckaert and Edmond deNiet of Philips patented an azimuth correction method that did not require dedicated reference tracks and could be retrofitted to any existing recording format. Its inventors proposed splitting each channel of the replay head into two half-width sub-channels; one magnetic subsystem would read the upper half of the track and the other would read the lower half, and the difference between their outputs would comprise the error signal. The system would work if and when the recorded signal has enough treble content; it would not work reliably with recordings with very little treble content and would not work at all with blank tapes. One year later, Rijckaert and de Niet patented a complete azimuth control system. Their servomechanism used a piezoelectric transducer and functioned in a manner similar to the device described in Jenkins' patent.
A practical, production-ready design of the RijckaertdeNiet head for cassette recorders was patented by Niro Nakamichi in November 1981. Fitting two replay sub-channels into 0,6 mm of a cassette track was a challenging task; according to the patent, each of two cores had to be made up of and thick lamination stacks; the windings had to be hidden in narrow grooves cut into the sides of the thickest stacks. The patented servo system, which was soon commercialized as the Nakamichi Auto Azimuth Correction (NAAC), analyzed only treble signals in the 2–8 kHz range; the deadband of the control loop was set with a simple diode limiter. The servomechanism was driven by an electric motor and used a complex gear train terminating in a wedge that pushed the pivoting replay head.
Unlike the RijckaertdeNiet system, the NAAC analyzed only the innermost (right) channel of a stereo tape. The outermost (left) channel should have been reproduced with a conventional full-track magnetic system. According to Nakamichi, the left channel of a cassette tape is more prone to dropouts and wear, and should not be used for extracting azimuth information; as a side benefit, a simplified control loop has to deal with only one error signal. A unidirectional, azimuth-sensing head would employ three magnetic subsystems – one full-track and two half-track – a bidirectional NAAC replay head would employ six. Bidirectional recording was not an option because a fixed, pivoting replay head would require two erase heads and two recording heads – too many for the limited space of the cassette tape guide. Niro Nakamichi and Kozo Kobayashi, lead designer of the Dragon, settled for a conventional three-head configuration with unidirectional recording only.
Introduction
The Nakamichi Dragon, the first production cassette deck built around Rijckaertde Niet and Niro Nakamichis's inventions, was introduced in North America in November 1982. At a price of , it replaced the far more expensive and already discontinued Nakamichi 1000ZXL as the company's flagship model. The name Dragon broke Nakamichi's tradition of using plain numeric model codes and was coined by company founder Etsuro Nakamichi, who died in the same month.
The deck was well-received by the press, scoring far above the competition. It became the new reference against which all competition was judged and remained so until the end of production. Competing products dubbed "Dragon slayers" of the late 1980s like Revox B215 or Tandberg 3014 or the flagship TEACs surpassed the Dragon in mechanical quality or functionality, but no one could beat it altogether. The combination of sound quality, function set and technology attained by Nakamichi in 1982 remained the apex of the cassette deck industry.
The only other auto-azimuth deck was released in 1983 by Marantz, which was then a Japanese subsidiary of Philips. The Marantz SD-930 had a unidirectional, three-head tape transport, a stereo azimuth-sensing replay head with four magnetic subsystems, and the proprietary Marantz Auto Azimuth Correction (MAAC) servomechanism with a piezoelectric actuator. It was manufactured for a short time in small numbers and remained almost unknown to the audiophile community and the press. In 1985, it was examined and tested by the German magazine Audio, which ranked it the worst of eight competing products.
Later years
In 1985, Nakamichi attempted to develop the Dragon marque into a premium sub-brand and released the Nakamichi Dragon-CT turntable, but no cassette decks named Dragon ever followed the original model. Manufacturing and aftermarket servicing of azimuth-sensing heads and transports was too expensive and too difficult, even for the company that invented them. After the Dragon, Nakamichi released only one NAAC-equipped model, the TD-1200 car stereo. The 'junior' line of Nakamichi autoreversing decks that was released from 1983 to 1985 used unidirectional transports that physically flipped the cassette but lacked azimuth correction. The 1986 Nakamichi CR-7, a new flagship deck that was manufactured alongside the Dragon, had a unidirectional transport with manual azimuth controls.
By 1988, development of high-end cassette decks had ended. These models were a concession to a small number of enthusiasts; too few to make any profits. Their value as halo drivers for selling low-cost consumer decks quickly eroded with the spread of digital technologies. Any further improvements in analog tape equipment, if possible at all, required substantial research expense but by that time, corporate resources were already committed to digital. In 1990, Nakamichi outsourced transport manufacturing to Sankyo and discontinued all models built around Nakamichi's own unidirectional tape transports.
Despite all setbacks, the original Dragon remained in production until 1993 and sales in Japan continued at least into 1994. The number of manufactured Dragons remains undisclosed but considering the eleven-year production run and worldwide sales network, it was very large for a halo product. By 1996, rising costs of Japanese labor and a declining market forced Nakamichi to shut down cassette deck production. The company made a mistake by focusing all efforts on Digital Audio Tape (DAT), which failed to gain a substantial market presence, and in 1997 the Nakamichi family sold the dying business to Grande Holdings.
Design features
Appearance and ergonomics
The Dragon faceplate, which descending from models ZX-7 and ZX-9, differs from them in the arrangement of secondary controls and recording level meter. The Dragon's oversized transport and calibration control buttons are arranged in rows like Dragon scales, and acquired a three-dimensional profile. The Dragon has a well-developed calibration panel and automated fader but otherwise its function set is minimal, assuming fully manual operation. Tape selection is manual with independent settings for bias and equalization (EQ); this allows the deck to record on Type II and Type IV tapes with 120μs time constant. Reviewers rated the Dragon ergonomics positively but noted many minor quirks and inconveniences. They said the deep window of the cassette well is too small; the right-side buttons – including the noise reduction and EQ switches – are too small and hard to read but easy to press accidentally. The resolution of the LED meter, like that of all segmented displays, is too coarse for precise adjustment. Nakamichi continued its tradition of giving cryptic names to standard tape types (EX, SX and ZX for Types I, II and IV respectively).
Recording channel calibration is performed separately for left and right channels in a sequence similar to that of the ZX-7 and ZX-9, except on the Dragon, the optimal relative azimuth is set automatically by the NAAC. Once the NAAC reaches equilibrium, which takes up to 15 seconds, the user aligns recording channel gain ("level") to match the tape's sensitivity using a 400 Hz test tone. Then, the user aligns the bias using 15 kHz test tone. Reviewers noted the manual calibration on the Dragon was as good as the automatic systems of its competitors. Manual process takes more time but allows control over frequency response to suit the user's taste. Calibration, however, cannot remedy faults of low-grade ferric tape, which according to Robertson, "would be bad choices for the Dragon anyway".
Tape transport
Nakamichi designers always followed the philosophy: "performance first, convenience second". This approach led them to adopt a discrete, three-head layout with independently adjustable recording and replay heads while the rest of the industry adopted tightly joined head assemblies. Next, they created a robust, double-capstan, "diffused resonance" tape transport and Nakamichi's pressure pad lifter – a tiny improvement that substantially reduced scrape flutter and modulation noise. Another innovation in the Dragon was direct drive of both capstans using low-cogging, brushless DC motors. Capstans traditionally had unequal diameters and different flywheel masses. The speeds of the quartz-controlled capstans were spread apart to ensure the trailing (braking) capstan always lagged behind the leading capstan by 0.2%, in either forward or reverse mode, to properly tension the tape and isolate it from the cassette shell. The third motor spun both tape spools, the fourth motor drove the NAAC servo, and the fifth one smoothly raised and lowered the head assembly in place of the usual solenoid). Both pinch rollers were enclosed in wraparound tape-guide blocks; ordinary unidirectional decks with double-capstan transports had only one such block. A side benefit of the Dragon's complex, five-motor arrangement was that the transport, except for the tape counter, did not use belts or springs.
The Dragon's discrete – mechanically, electrically and magnetically independent – heads were rated for 10,000 hours of replay or recording. To prevent early formation of a wear groove, which usually destroys the left channel audio, the heads were pre-slotted at the tape edges. This standard feature of reel-to-reel studio recorders had never been used in cassette decks before. The cores of the recording and replay heads were made of Nakamichi's "crystalloy", and the double-gapped erase head used a ferrite and sendust core. The two-track recording head has a gap of 3.5 μm and the four-track, six-channel replay head has a gap of 0.6 μm; theoretically, the latter allows reproduction of frequencies up to 40 kHz.
Nakamichi auto azimuth correction (NAAC) operates continuously in either replay or recording mode and is able to correct azimuth errors of up to 12 arc minutes. The NAAC has no memory: each tape eject and each change of replay direction erases the current setting and returns the replay head to its default position. The systems is reactivated immediately upon pressing the play button. The head remains stationary if the detected azimuth error lies within the deadband limits; higher error values engage servomechanism action. When the recorded signal has sufficient content, head alignment to 1 arc-minute precision takes from 1
to 5 seconds and usually remains unnoticed by the listener. If the recorded signal contains very little high-frequency energy, the system detects uncertainty and slows down or does not engage at all. NAAC is not completely foolproof; it can be confused and disturbed by unusually strong ultrasonic signals and very fast audio-frequency sweeps. Such unnatural, non-musical signals cause "some hunting" as the NAAC tries to seek a nonexistent or quickly changing target.
Audio signal path
The Dragon's replay audio path has six identical head amplifiers; two for forward direction, two for reverse, and two for the NAAC control channel – one each for forward and reverse. Each head amplifier is an active filter using a discrete JFET front stage that is AC-coupled to an operational amplifier (op amp) in inverting configuration. This was the first time Nakamichi used op amps rather than discrete transistors in head amplifiers. Their feedback networks shape low and middle-frequency parts of the IEC equalization curve, and crudely approximate its treble part. The signal then passes through CMOS switches that select either forward or reverse channels and is then routed to noise reduction integrated circuits (IC), where the treble equalization at either 120 μs or 70 μs is completed. The Dolby B/C compander is a true "double Dolby" compander with two NE652 ICs in the replay path and two more in the recording path. A similar arrangement, excluding bidirectional replay features, was later used in Nakamichi CR-7. The Dragon's recording path, traditionally for upper-range Nakamichi decks, has individual analog bias adjustment and no Dolby HX Pro or any other kind of dynamic biasing.
Reception and reviews
Independent measurements
The Dragon's wow and flutter announced by Nakamichi – 0.019% weighted RMS and 0.04% weighted peak – were twice as low as those of Nakamichi 1000ZXL and, for a while, the lowest on the market. Independent tests confirmed the manufacturer's figures; according to Stereo Review, test results revealed the performance of the equipment that recorded the test tape rather than that of the Dragon. In the late 1980s ASC, Onkyo, Studer and TEAC reached a similar level of wow and flutter but the Dragon's achievement was still the best in industry. Long-term speed stability of the Dragon was exemplary but that was typical for quartz-controlled transports. The Dragon's absolute speed error (+0.2+0.5%) was typical for the industry and presented no audible distraction.
According to Stereo Review measurements, the Dragon's dynamic range for Type I, II and IV tapes equaled 54, 56.5 and 59 decibels (dB) respectively. These were record-high figures for cassette machines, beating the Tandberg 3014 and the Revox B215 in comparative tests by 4-5 dB. The Dragon's replay audio path generated far less treble noise; tape hiss reproduced with the Dragon appeared subjectively quieter and euphonic. Maximum output levels (MOL) of the Dragon were also the best in class, marginally better than those of the Tandberg but almost 4 dB better than those of the Revox.
The lower boundary of the Dragon's frequency response, measured to within ±3 dB, extends to 1112 Hz. Nakamichi said the special shape of their heads substantially reduced the contour effect, effectively suppressing low-frequency headbump (poletip resonance). This is only true for the replay head. The combined recording and replay frequency response, according to independent testers, exhibits a comb-like resonant pattern. The lowest and most prominent peak or headbump, which lies at around 15 Hz, can be suppressed with a user-defeatable subsonic filter.
The upper boundary for low-level (-20 dB) signals extends to 2224 kHz depending on tape type. This is much lower than the record set by the Nakamichi 1000ZXL (2628 kHz), and is typical for all flagship models of the 1980s. The significance of this parameter was often overstated by hi-fi enthusiasts; professionals did not rate it as important because any professional deck easily exceeded the 20 kHz mark. More important was the high-level frequency response, which is largely limited by the tape and tape-head interaction. Here, the Dragon demonstrated very good performance, marginally better than Tandberg and significantly better than the Revox with Type I and Type IV (but not Type II) tapes.
Controversy about equalization
Reviewers who examined the Dragon's frequency response noted its abnormal behavior in the upper treble. The Dragon played back test tapes with a prominent treble boost, reaching +4 dB at 18 kHz. This would audibly brighten up music recorded on standard equipment. Noel Keywood wrote that Dragon's brightness would benefit most tapes recorded on inferior decks but might be annoying or unpleasant at times.
The treble boost of Nakamichi's cassette decks was well known to the press before the advent of the Dragon; it had been discussed in American journals in 1981 and 1982. The root of the problem was hidden in the language of the IEC standard enacted in 1978 and based on the original, outdated 1963 Philips specification. The standard was written in terms of remanent magnetic flux recorded on tape. Flux, the principal metric of recorded signals, cannot be directly measured; it can only be picked up with a magnetic head, which converts the faint magnetic field into electric current, losing some energy in the process of conversion. Replay head losses rise with frequency and cannot usually be reliably calculated due to the complexity of underlying phenomena.
To make things easier for the industry, the IEC tacitly allowed manufacturers to use the output of the IEC reference replay head as the definitive measure of the recorded signal. Losses in the reference head had to be compensated for with a reciprocal treble boost during recording. This arrangement became a norm in the industry but was never properly formalized. By 1981, improvements in tape head technology made the IEC reference head obsolete; new, top-of-the-line replay heads had far lower treble losses and did not need as much pre-emphasis. Test tapes, however, were routinely made to suit the old reference head. Overall, test-tape production was in disarray, which worsened compatibility issues. Classic Philips calibration tapes were technologically obsolete and samples were inconsistent. New TDK tapes were even less consistent and differed from Philips tapes while TEAC tapes were different from those from both Philips and TDK. All test tapes were recorded with undocumented pre-emphasis and with a slightly different azimuth.
Nakamichi never subscribed to the informal industry convention but followed the Philips and IEC standards literally, and insisted losses in the replay head must be compensated for in the replay chain. Pre-emphasis in the recording chain should only compensate for recording losses; according to Nakamichi, anything else was unacceptable. The company insisted estimation of treble losses in well-engineered heads presents no problems. As a result, Nakamichi's recording chains and calibration tapes were consistently duller than those of the competition and Nakamichi's replay chains were consistently brighter. This difference was gradually fading as the company's competitors gradually improved their own replay heads and tacitly adopted Nakamichi's approach. BASF, a principal player in the IEC and manufacturer of the IEC Type I and Type II reference tapes, backed Nakamichi with a statement saying that, as of December 1981, Nakamichi decks were fully compatible with BASF-made reference tapes.
Overall ratings
Throughout the 1980s, high fidelity magazines called the Nakamichi Dragon the best cassette deck they had ever tested. In comparative tests by Audio (West Germany, 1985) and Stereo Review (United States, 1988), only the Revox B215 equaled the Dragon in sound quality. The Revox surpassed the Dragon in mechanical aspects and probably in long-term durability but lacked auto-reverse, automatic azimuth adjustment and the versatility of manual calibration. Flagship decks by ASC, Harman Kardon, Onkyo, Tandberg and TEAC, and the auto-azimuth Marantz SD-930, were distinctly inferior to the Dragon. The Dragon's status as Nakamichi's best deck is debatable. According to Paul Wilkins of Bowers & Wilkins – long-term Nakamichi distributor and service provider – the 1000ZXL is the most complicated and rarest model, the less expensive CR-7 is equivalent to the Dragon in terms of sound quality but lacks auto-reverse and auto-azimuth functions.
These functions, particularly auto-azimuth, changed the market in favor of the Dragon. It was not just another precision recording machine; it was a player that could adapt to almost any cassette recorded on almost any other deck. This attracted affluent yuppie buyers and sealed the Dragon's reputation as a desirable status symbol. In the late 1990s, after Nakamichi failed, the company's products acquired cult status. Barry Wilson of Stereophile compared Nakamichi to the status of Harley-Davidson among motorcyclists and the Gibson Les Paul among guitarists. McIntosh amplifiers and Linn turntables were just as desirable but Nakamichi's number of loyal owners exceeded both. Worldwide sales figures for the Dragon are unknown but around 130,000 Nakamichi decks were sold in the United Kingdom alone By 1998, Nakamichi fans had already formed vibrant internet communities; their online activity disseminated and reinforced the belief in the "legendary Nakamichi warmth". The Dragon was revered as "the Holy Grail of what could be accomplished at 1" – the tape speed of the cassette.
In the 21st century, the reputation of the Dragon has been reinforced by collectors, internet traders and a few repair technicians. Critics say the legend of the Dragon did not pass the test of time. The complex, five-motor transport, which was once hailed as "a masterpiece of engineering" and an "engineering tour de force", was not as robust as simpler, unidirectional transports. The Dragons that are sold at internet auctions need extensive repairs; the small number of Nakamichi service technicians is shrinking and parts must be scavenged from non-functional Dragons. The cost of a complete overhaul in 2014 was comparable with the price of a new deck in the 1990s.
Notes
References
Sources
Reviews and comparative tests
Nakamichi publications
A collection of reprints from the press and original statements by Nakamichi and BASF staff:
Products introduced in 1982
Audiovisual introductions in 1982
Tape recording
Dutch inventions
Japanese inventions | Nakamichi Dragon | [
"Technology"
] | 6,039 | [
"Recording devices",
"Tape recording"
] |
63,690,330 | https://en.wikipedia.org/wiki/32K%20resolution | 32K resolution refers to a display resolution of approximately 32,000 pixels horizontally. A resolution of 30720 × 17280 for an aspect ratio of 16:9 is speculated to be standardized. This doubles the pixel count of 16K in each dimension, for a total of 530.8 megapixels (530,841,600 pixels), 4 times as many pixels as the 16K resolution. It has 16 times as many pixels as 8K resolution, 64 times as many pixels as 4K resolution, 256 times the pixels as Full HD or 1080p resolution, and 576 times the pixels as HD or 720p resolution.
There are plans from different groups to start implementing 32K technology. While there are a few cameras that can shoot in 32K resolution, even 8K still does not have as widespread usage as 1080p and 4K do. There are less than 3% of televisions supporting 8K (with only some 9th generation gaming consoles supporting it), and none using 16K.
Two primary limiting factors in 32K are display resolution and CPU/GPU capability.
History
Development
In 2018, Sony installed a 16K screen into the front of a cosmetics store in Yokohama, south of Tokyo. The widescreen display is believed to be the largest 16K screen yet. Sony has plans to make the product available, in custom sizes, for wealthy consumers. They are also currently working on developing a 32K display.
Currently, it is possible to run 32K resolutions using multi-monitor setups with AMD Eyefinity or Nvidia Surround using 16 8K TVs or monitors. However, this type of setup is costly and difficult to implement. No displays or monitors singly capable of displaying a 32K resolution are available to the consumer market yet.
Technology
No handheld devices yet.
Cameras in development
The Linea HS 32K
Cameras
Teledyne DALSA 32K Super Resolution CLHS Camera
Gaming
Gaming at 32K is very unlikely to be possible in the near future. To achieve the resolution, sixteen 8K televisions or monitors in a multi-monitor setups with AMD Eyefinity or Nvidia Surround would be required.
Editing
Currently, only Blackmagic Design's DaVinci Resolve 17 supports editing at 32K resolution.
See also
4K resolution digital video formats with a horizontal resolution of around 4,000 pixels
5K resolution digital video formats with a horizontal resolution of around 5,000 pixels, aimed at non-television computer monitor usage
8K resolution digital video formats with a horizontal resolution of around 8,000 pixels
10K resolution digital video formats with a horizontal resolution of around 10,000 pixels, aimed at non-television computer monitor usage
16K resolution digital video formats with a horizontal resolution of around 16,000 pixels
Ultra-high-definition television (UHDTV) digital video formats with resolutions of 4K () and 8K ()
Rec. 2020 ITU-R Recommendation for UHDTV
Digital movie camera
Digital cinematography makes extensive use of UHD video
List of large sensor interchangeable-lens video cameras
References
Digital imaging
Display technology
Film and video technology | 32K resolution | [
"Engineering"
] | 633 | [
"Electronic engineering",
"Display technology"
] |
63,690,875 | https://en.wikipedia.org/wiki/Transposed%20Patern%C3%B2%E2%88%92B%C3%BCchi%20reaction | The transposed Paternò−Büchi reaction involves a ππ* excited state of alkene reacting with a ground state carbonyl functionality. This is reversal of the traditional Paternò−Büchi reaction where an excited carbonyl group reacts with a ground state alkene. This strategy was first reported by Sivaguru and co-workers with reaction of enamides.
References
Organic reactions | Transposed Paternò−Büchi reaction | [
"Chemistry"
] | 84 | [
"Organic reactions"
] |
63,690,941 | https://en.wikipedia.org/wiki/Aza%20Patern%C3%B2%E2%88%92B%C3%BCchi%20reaction | Aza Paternò−Büchi reaction involves an ππ* excited state of alkene reacting with a ground state imine. This strategy was developed by the laboratory Sivaguru and co-workers to overcome the shortcomings involving direct excitation of imines. Traditionally addition of excited imines to carbon-carbon double bonds involves making the imines as part of a carbocycle.
References
Organic reactions | Aza Paternò−Büchi reaction | [
"Chemistry"
] | 88 | [
"Organic reactions"
] |
63,691,064 | https://en.wikipedia.org/wiki/Phenylephrine/ketorolac | Phenylephrine/ketorolac, sold under the brand name Omidria, is a combination drug used during cataract surgery or intraocular lens replacement to prevent intraoperative miosis and to reduce postoperative pain. It contains phenylephrine and ketorolac.
Phenylephrine/ketorolac was approved for medical use in the United States in May 2014, and in the European Union in July 2015.
References
External links
Alpha-1 adrenergic receptor agonists
Combination drugs
Nonsteroidal anti-inflammatory drugs
Ophthalmology drugs
Vasoconstrictors | Phenylephrine/ketorolac | [
"Chemistry"
] | 133 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
63,694,205 | https://en.wikipedia.org/wiki/Inductive%20tensor%20product | The finest locally convex topological vector space (TVS) topology on the tensor product of two locally convex TVSs, making the canonical map (defined by sending to ) continuous is called the inductive topology or the -topology. When is endowed with this topology then it is denoted by and called the inductive tensor product of and
Preliminaries
Throughout let and be locally convex topological vector spaces and be a linear map.
is a topological homomorphism or homomorphism, if it is linear, continuous, and is an open map, where the image of has the subspace topology induced by
If is a subspace of then both the quotient map and the canonical injection are homomorphisms. In particular, any linear map can be canonically decomposed as follows: where defines a bijection.
The set of continuous linear maps (resp. continuous bilinear maps ) will be denoted by (resp. ) where if is the scalar field then we may instead write (resp. ).
We will denote the continuous dual space of by and the algebraic dual space (which is the vector space of all linear functionals on whether continuous or not) by
To increase the clarity of the exposition, we use the common convention of writing elements of with a prime following the symbol (e.g. denotes an element of and not, say, a derivative and the variables and need not be related in any way).
A linear map from a Hilbert space into itself is called positive if for every In this case, there is a unique positive map called the square-root of such that
If is any continuous linear map between Hilbert spaces, then is always positive. Now let denote its positive square-root, which is called the absolute value of Define first on by setting for and extending continuously to and then define on by setting for and extend this map linearly to all of The map is a surjective isometry and
A linear map is called compact or completely continuous if there is a neighborhood of the origin in such that is precompact in
In a Hilbert space, positive compact linear operators, say have a simple spectral decomposition discovered at the beginning of the 20th century by Fredholm and F. Riesz:
There is a sequence of positive numbers, decreasing and either finite or else converging to 0, and a sequence of nonzero finite dimensional subspaces of () with the following properties: (1) the subspaces are pairwise orthogonal; (2) for every and every ; and (3) the orthogonal of the subspace spanned by is equal to the kernel of
Notation for topologies
denotes the coarsest topology on making every map in continuous and or denotes endowed with this topology.
denotes weak-* topology on and or denotes endowed with this topology.
Every induces a map defined by is the coarsest topology on making all such maps continuous.
denotes the topology of bounded convergence on and or denotes endowed with this topology.
denotes the topology of bounded convergence on or the strong dual topology on and or denotes endowed with this topology.
As usual, if is considered as a topological vector space but it has not been made clear what topology it is endowed with, then the topology will be assumed to be
Universal property
Suppose that is a locally convex space and that is the canonical map from the space of all bilinear mappings of the form going into the space of all linear mappings of
Then when the domain of is restricted to (the space of separately continuous bilinear maps) then the range of this restriction is the space of continuous linear operators
In particular, the continuous dual space of is canonically isomorphic to the space the space of separately continuous bilinear forms on
If is a locally convex TVS topology on ( with this topology will be denoted by ), then is equal to the inductive tensor product topology if and only if it has the following property:
For every locally convex TVS if is the canonical map from the space of all bilinear mappings of the form going into the space of all linear mappings of then when the domain of is restricted to (space of separately continuous bilinear maps) then the range of this restriction is the space of continuous linear operators
See also
References
Bibliography
External links
Nuclear space at ncatlab
Functional analysis
Topological vector spaces
Topology
Topological tensor products | Inductive tensor product | [
"Physics",
"Mathematics",
"Engineering"
] | 878 | [
"Functions and mappings",
"Tensors",
"Functional analysis",
"Vector spaces",
"Mathematical objects",
"Space (mathematics)",
"Topological vector spaces",
"Topology",
"Space",
"Mathematical relations",
"Geometry",
"Spacetime",
"Topological tensor products"
] |
63,694,441 | https://en.wikipedia.org/wiki/TCN%20Protocol | The Temporary Contact Numbers Protocol, or TCN Protocol, is an open source, decentralized, anonymous exposure alert protocol developed by Covid Watch in response to the COVID-19 pandemic. The Covid Watch team, started as an independent research collaboration between Stanford University and the University of Waterloo was the first in the world to publish a white paper, develop, and open source fully anonymous Bluetooth exposure alert technology in collaboration with CoEpi after writing a blog post on the topic in early March.
Covid Watch's TCN Protocol received significant news coverage and was followed by similar decentralized protocols in early April 2020 like DP-3T, PACT, and Google/Apple Exposure Notification framework. Covid Watch then helped other groups like the TCN Coalition and MIT SafePaths implement the TCN Protocol within their open source projects to further the development of decentralized technology and foster global interoperability of contact tracing and exposure alerting apps, a key aspect of achieving widespread adoption. Covid Watch volunteers and nonprofit staff also built a fully open source mobile app for sending anonymous exposure alerts first using the TCN Protocol and later using the very similar Google/Apple Exposure Notification Framework (ENF).
The protocol, like BlueTrace and the Google / Apple contact tracing project, use Bluetooth Low Energy to track and log encounters with other users. The major distinction between TCN and protocols like BlueTrace is the fact the central reporting server never has access to contact logs nor is it responsible for processing and informing clients of contact. Because contact logs are never transmitted to third parties, it has major privacy benefits over approaches like the one used in BlueTrace. This approach however, by its very nature, does not allow for human-in-the-loop reporting, potentially leading to false positives if the reports are not verified by public health agencies.
The TCN protocol received notoriety as one of the first widely released digital contact tracing protocols alongside BlueTrace, the Exposure Notification framework, and the Pan-European Privacy-Preserving Proximity Tracing (PEPP-PT) project. It also stood out for its incorporation of blockchain technology, and its influence over the Google/Apple project.
Overview
The TCN protocol works off the basis of Temporary Contact Numbers (TCN), semi-random identifiers derived from a seed. When two clients encounter each other, a unique TCN is generated, exchanged, and then locally stored in a contact log. Then, once a user tests positive for infection, a report is sent to a central server. Each client on the network then collects the reports from the server and independently checks their local contact logs for a TCN contained in the report. If a matching TCN is found, then the user has come in close contact with an infected patient, and is warned by the client. Since each device locally verifies contact logs, and thus contact logs are never transmitted to third parties, the central reporting server cannot by itself ascertain the identity or contact log of any client in the network. This is in contrast to competing protocols like BlueTrace, where the central reporting server receives and processes client contact logs.
Temporary contact numbers
The entire protocol is based on the principle of temporary contact numbers (TCN), a unique and anonymous 128-bit identifier generated deterministically from a seed value on a client device. TCNs are used to identify people with which a user has come in contact, and the seed is used to compactly report infection to a central reporting server. TCN reports are authenticated to be genuine by a secret held only by the client.
Generation
To generate a TCN, first a report authorization key (RAK) and report verification key (RVK) are created as the signing and verification keys of a signature scheme (RAK-RVK pair). In the reference implementation this pair is created using the Ed25519 signature scheme. Then, using the RAK an initial temporary contact key (TCK) is generated using the algorithm , where is the SHA-256 hash function as . This TCK is not used to generate any TCNs, but is used in the next TCK; where all future TCKs are calculated using the algorithm . A 128 bit TCN is then generated from a given TCK using the algorithm , where formats a supplied number as a little endian unsigned 2 byte integer, and is the SHA-256 hash function as . The following diagram demonstrates the key derivation process:TCNs are unique to each device encounter, and RAK-RVK pairs are cycled at regular intervals to allow a client to report only specific periods of contact.
Reporting
When a client wishes to submit a report for the TCN indices to , it structures the report as . A signature is then calculated using the RAK, and it is transmitted to the server as .
Because any given TCK can only be used to derive an equal or higher indexed TCNs, by submitting no encounters prior to can be calculated. However, there is no upper limit to encounters calculated using the same RAK-RVK pair, which is why they are cycled often. To prevent clients calculating unused TCNs, indicates the last TCN index generated with the given RVK. Additionally, since the RVK is used to calculate a TCK, and is provided, no valid TCNs in the reporting period can be derived from an illegitimate report. The only correct TCN calculable from a mismatched RVK and is , the TCN before the start of the reporting period.
Once a report is received, clients individually recalculate TCKs and TCNs for a given period using the original algorithms:This is used by client devices to check their local contact logs for potential encounters with the infected patient, but has the dual benefit of verifying reports since false reports will never produce matching TCNs.
Memo
In the report structure, the memo is a space for freeform messages that differ between TCN implementations. The section is between 2 and 257 bytes, and made up of a tag identifying the specific implementation, as well as a data and data length pair. It is formatted as . The data is standardized for different tags, and can be as follows:
Technical specification
The protocol can be divided into two responsibilities: an encounter between two devices running TCN apps, and the notification of potential infection to users that came in contact with a patient. For the purposes of this specification, these areas are named the encounter handshake, and infection reporting. The encounter handshake runs on Bluetooth LE and defines how two devices acknowledge each other's presence. The infection reporting is built on HTTPS and defines how infection notices are distributed among clients.
Encounter handshake
When two devices come within range of each other, they exchange a handshake containing TCNs. In order to achieve this the encounter handshake operates in two modes (both with two sub-modes), broadcast oriented and connection oriented. Broadcast oriented operates using the modes broadcaster and observer, while connection oriented operates using peripheral and central. The two modes are used to circumvent certain device limitations, particularly in regard to iOS restrictions in place before version 13.4. In both modes the protocol is identified with the 16 bit UUID .
In broadcast mode, a broadcaster advertises a 16-byte TCN using the service data field of the advertisement data. The observer reads the TCN from this field. In connection-oriented mode, the peripheral advertises using the UUID. The service exposes a read and writeable packet for sharing TCNs. After sharing a TCN, the central disconnects from the peripheral.
Infection reporting
When a user tests positive for infection, they upload a signed report, allowing the past 14 days of encounters to be calculated, to a central server. On a regular basis, client devices download reports from the server and check their local contact logs using the verification algorithm. If there is a matching record, the app notifies the user to potential infection.
TCN Coalition
On 5 April 2020, the global TCN Coalition was founded by Covid Watch and other groups that had coalesced around what was essentially the same approach and largely overlapping protocols, with the goal to reduce fragmentation, and enable global interoperability of tracing and alerting apps, a key aspect of achieving widespread adoption. The TCN Coalition also helped establish the Data Rights for Digital Contact Tracing and Alerting framework, which functions as a bill of rights for users of such apps.
Currently the protocol is used by TCN Coalition members CoEpi and Covid Watch, and was likely a source of inspiration for the similar Google / Apple contact tracing project.
See also
BlueTrace
Google / Apple contact tracing project
Pan-European Privacy-Preserving Proximity Tracing
References
External links
Covid Watch
TCN Coalition
Specification and reference implementation
Application layer protocols
Software associated with the COVID-19 pandemic
Bluetooth software
Medical software
Android (operating system) software
IOS software
2020 software
Software using the MIT license
Digital contact tracing protocols
Digital contact tracing protocols with decentralized reporting | TCN Protocol | [
"Biology"
] | 1,847 | [
"Medical software",
"Medical technology"
] |
63,694,803 | https://en.wikipedia.org/wiki/Master%20mix%20%28PCR%29 | A master mix is a mixture containing precursors and enzymes used as an ingredient in polymerase chain reaction techniques in molecular biology. Such mixtures contain a mixture dNTPs (required as a substrate for the building of new DNA strands), MgCl2, Taq polymerase (an enzyme required to building new DNA strands), a pH buffer and come mixed in nuclease-free water.
Master mixes for real-time PCR include a fluorescent compound (frequently SYBR green), and the choice of mix also influence test sensitivity and consistency.
Differences in the choice of master mixes can sometimes explain difference in experimental results, a particular case being the measurement of telomere length.
References
DNA sequencing | Master mix (PCR) | [
"Chemistry",
"Biology"
] | 144 | [
"Molecular biology stubs",
"Molecular biology techniques",
"DNA sequencing",
"Molecular biology"
] |
63,694,831 | https://en.wikipedia.org/wiki/Methyltriphenylphosphonium%20bromide | Methyltriphenylphosphonium bromide is the organophosphorus compound with the formula [(C6H5)3PCH3]Br. It is the bromide salt of a phosphonium cation. It is a white salt that is soluble in polar organic solvents.
Synthesis and reactions
Methyltriphenylphosphonium bromide is produced by treating triphenylphosphine with methyl bromide:
Ph3P + CH3Br → Ph3PCH3Br
Methyltriphenylphosphonium bromide is the principal precursor to methylenetriphenylphosphorane, a useful methylenating reagent. This conversion is achieved by treating methyltriphenylphosphonium bromide with strong base.
Ph3PCH3Br + BuLi → Ph3PCH2 + LiBr + BuH
References
Quaternary phosphonium compounds
Bromides
Organophosphorus compounds | Methyltriphenylphosphonium bromide | [
"Chemistry"
] | 202 | [
"Functional groups",
"Salts",
"Organic compounds",
"Bromides",
"Organophosphorus compounds"
] |
63,695,543 | https://en.wikipedia.org/wiki/Mudboil | Mudboils are muddy springs composed of water, fine sand and silt, and dissolved salt chiefly found in the Tully Valley in Onondaga County, in central New York State, although they have also been observed for shorter periods of time following earthquakes in Alaska and California. They range from several inches to more than 30 feet in diameter, and ebb and flow dynamically: some will discharge large amounts of sediment over several days and then stop flowing, while others will flow continuously for multiple years. The phenomenon has been observed since the late 1890s.
The Tully Valley mudboils are associated with a history of brine extraction in the area, which began in the late 1880s. The halite beds in the Tully Valley lie under a 400-foot layer of glacial sediments and a 1000-foot layer of shale and limestone that separated them from the aquifer until salt extraction began. Brining has also caused ground subsidence in the areas above the salt beds.
Tons of sediment, as well as dissolved salt, are deposited by the mudboils into Onondaga Creek on a daily basis. Members of the Onondaga Nation report that as recently as the 1940s, the now-turbid water was clear and that tribe members used to swim and fish in the river.
See also
Mudpot
Frost boils, also sometimes known as mud boils
References
Hydrology | Mudboil | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 278 | [
"Hydrology",
"Hydrology stubs",
"Environmental engineering"
] |
58,492,716 | https://en.wikipedia.org/wiki/Post-work%20society | In futurology, political science, and science fiction, a post-work society is a society in which the nature of work has been radically transformed and traditional employment has become obsolete due to technological progress.
Some post-work theorists imagine the complete automation of all jobs, or at least the takeover of all monotonous, rule-based, predictable and repetitive (and thus unworthy of humans) tasks in the future by ultimately cheaper, faster, more efficient, more reliable and more accurate intelligent machines. Additionally, these machines can work in harsher conditions and for longer periods of time without stopping than humans, which is expected to lead to a transition period of rapid economic growth, despite high rates of ever-increasing human unemployment. Overall, this development is expected to lead to an enormous increase in prosperity, provided that the wealth is redistributed.
Future directions
Future directions include the reshaping of the human role in the workplace, stressing the relative strengths of humans capable of adapting and integrating technology into their work and interaction. In addition to these capabilities, scholars emphasize the importance of humans taking advantage of these relative strengths, offering several areas which humans can remain competent in a rapidly developing workplace. These include emotional intelligence, service orientation, resource management skills, communication skills, and entrepreneurship skills.
Scholarly literature defines such areas where machines may surpass humans as "task encroachment". "Task encroachment" presents an issue of growing encroachment of AI and automation into human work, especially in manual and cognitive tasks. It is estimated that approximately 40% of all working hours will be affected by AI models. It has been proposed for humanity to pivot towards roles that require emotional intelligence and interpersonal skills, assumed to be more uniquely humans. However, studies show that in some contexts, modern chatbots generate answers that are rated as more empathetic and qualitative than human ones.
Some theories of a post-work society focus on challenging the priority of the work ethic, and on the celebration of nonwork activities. These theories also underscore the importance of developing community-based activities and self-improvement programs to fill the void left by traditional labor structures.
Near-term practical proposals closely associated with post-work theory include the implementation of a universal basic income, as well as the reduction of the length of a working day and the number of days of a working week. Increased focus on what post-work society would look like has been driven by reports such as one in 2018 that states 47% of jobs in the United States could be automated. Because of increasing automation and the low price of maintaining an automated workforce compared to one dependent on human labor, it has been suggested that post-work societies would also be ones of post-scarcity.
According to Nick Bostrom, advanced artificial intelligence has the potential to not only automate jobs and create abundance, but also undermine the purpose of many leisure activities, such as shopping, gardening, or even parenting.
See also
Critique of work
Four-day workweek
In Praise of Idleness
Humans Need Not Apply
Imagination age
Post-capitalism
Refusal of work
Tang ping ("lying flat")
Technological utopianism
Inventing the Future: Postcapitalism and a World Without Work
The End of Work
The Future of Work and Death
Workism
References
Further reading
Impact of automation
Futures studies | Post-work society | [
"Engineering"
] | 677 | [
"Impact of automation",
"Automation"
] |
58,494,813 | https://en.wikipedia.org/wiki/Pacific%20Northwest%20water%20resource%20region | The Pacific Northwest water resource region is one of 21 major geographic areas, or regions, in the first level of classification used by the United States Geological Survey to divide and sub-divide the United States into successively smaller hydrologic units. These geographic areas contain either the drainage area of a major river, or the combined drainage areas of a series of rivers.
The Pacific Northwest region, which is listed with a 2-digit hydrologic unit code (HUC) of 17, has an approximate size of , and consists of 12 subregions, which are listed with the 4-digit HUCs 1701 through 1706.
This region includes the drainage within the United States that ultimately discharges into: (a) the Strait of Georgia and of Strait of Juan de Fuca, and (b) the Pacific Ocean within the states of Oregon and Washington; and that part of the Great Basin whose discharge is into the state of Oregon. Includes all of Washington and parts of California, Idaho, Montana, Nevada, Oregon, Utah, and Wyoming.
List of water resource subregions
See also
List of rivers in the United States
Water resource region
References
Lists of drainage basins
Drainage basins
Watersheds of the United States
Regions of the United States
Resource
Water resource regions | Pacific Northwest water resource region | [
"Environmental_science"
] | 250 | [
"Hydrology",
"Drainage basins"
] |
58,495,269 | https://en.wikipedia.org/wiki/Self-similar%20solution | In the study of partial differential equations, particularly in fluid dynamics, a self-similar solution is a form of solution which is similar to itself if the independent and dependent variables are appropriately scaled. Self-similar solutions appear whenever the problem lacks a characteristic length or time scale (for example, the Blasius boundary layer of an infinite plate, but not of a finite-length plate). These include, for example, the Blasius boundary layer or the Sedov–Taylor shell.
Concept
A powerful tool in physics is the concept of dimensional analysis and scaling laws. By examining the physical effects present in a system, we may estimate their size and hence which, for example, might be neglected. In some cases, the system may not have a fixed natural length or time scale, while the solution depends on space or time. It is then necessary to construct a scale using space or time and the other dimensional quantities present—such as the viscosity . These constructs are not 'guessed' but are derived immediately from the scaling of the governing equations.
Classification
The normal self-similar solution is also referred to as a self-similar solution of the first kind, since another type of self-similar exists for finite-sized problems, which cannot be derived from dimensional analysis, known as a self-similar solution of the second kind.
Self-similar solution of the second kind
The early identification of self-similar solutions of the second kind can be found in problems of imploding shock waves (Guderley–Landau–Stanyukovich problem), analyzed by G. Guderley (1942) and Lev Landau and K. P. Stanyukovich (1944), and propagation of shock waves by a short impulse, analysed by Carl Friedrich von Weizsäcker and Yakov Borisovich Zel'dovich (1956), who also classified it as the second kind for the first time. An independent study about the same field was published by Leonid Ivanovich Sedov in 1959. A complete description was made in 1972 by Grigory Barenblatt and Yakov Borisovich Zel'dovich. The self-similar solution of the second kind also appears in different contexts such as in boundary-layer problems subjected to small perturbations, as was identified by Keith Stewartson, Paul A. Libby and Herbert Fox. Moffatt eddies are also a self-similar solution of the second kind. The geneal mathematical properties of asymptotic behavior of solutions and self-similar solutions can be found in.
Examples
Rayleigh problem
A simple example is a semi-infinite domain bounded by a rigid wall and filled with viscous fluid. At time the wall is made to move with constant speed in a fixed direction (for definiteness, say the direction and consider only the plane), one can see that there is no distinguished length scale given in the problem. This is known as the Rayleigh problem. The boundary conditions of no-slip is
Also, the condition that the plate has no effect on the fluid at infinity is enforced as
Now, from the Navier-Stokes equations
one can observe that this flow will be rectilinear, with gradients in the direction and flow in the direction, and that the pressure term will have no tangential component so that
. The component of the Navier-Stokes equations then becomes
and the scaling arguments can be applied to show that
which gives the scaling of the co-ordinate as
.
This allows one to pose a self-similar ansatz such that, with and dimensionless,
The above contains all the relevant physics and the next step is to solve the equations, which for many cases will include numerical methods. This equation is
with solution satisfying the boundary conditions that
which is a self-similar solution of the first kind.
Semi-infinite solid approximation
In transient heat transfer applications, such as impingement heating on a ship deck during missile launches and the sizing of thermal protection systems, self-similar solutions can be found for semi-infinite solids. The governing equation when heat conduction is the primary heat transfer mechanism is the one-dimensional energy equation:where is the material's density, is the material's specific heat capacity, is the material's thermal conductivity. In the case when the material is assumed to be homogeneous and its properties constant, the energy equation is reduced to the heat equation:with being the thermal diffusivity. By introducing the similarity variable and assuming that , the PDE can be transformed into the ODE:If a simple model of thermal protection system sizing is assumed, where decomposition, pyrolysis gas flow, and surface recession are ignored, with the initial temperature and a constant surface temperature , then the ODE can be solved for the temperature at a depth and time :where is the error function.
References
Fluid dynamics
Partial differential equations | Self-similar solution | [
"Chemistry",
"Engineering"
] | 985 | [
"Piping",
"Chemical engineering",
"Fluid dynamics"
] |
58,495,828 | https://en.wikipedia.org/wiki/Estradiol%20dibutyrate | Estradiol dibutyrate (EDBu), or estradiol dibutanoate, is an estrogen medication and an estrogen ester – specifically, a diester of estradiol – which is no longer used. It was a component of Triormon Depositum, a combination formulation of estradiol dibutyrate, testosterone caproate, and hydroxyprogesterone heptanoate which was developed in the 1950s.
See also
List of estrogen esters § Estradiol esters
Estradiol dibutyrate/hydroxyprogesterone heptanoate/testosterone caproate
References
Abandoned drugs
Butyrate esters
Estradiol esters
Synthetic estrogens | Estradiol dibutyrate | [
"Chemistry"
] | 152 | [
"Drug safety",
"Abandoned drugs"
] |
58,496,647 | https://en.wikipedia.org/wiki/Nicolosi%20globular%20projection | The Nicolosi globular projection is a polyconic map projection invented about the year 1000 by the Iranian polymath al-Biruni. As a circular representation of a hemisphere, it is called globular because it evokes a globe. It can only display one hemisphere at a time and so normally appears as a "double hemispheric" presentation in world maps. The projection came into use in the Western world starting in 1660, reaching its most common use in the 19th century. As a "compromise" projection, it preserves no particular properties, instead giving a balance of distortions.
History
Abū Rayḥān Muḥammad ibn Aḥmad Al-Bīrūnī, who was the foremost Muslim scholar of the Islamic Golden Age, invented the first recorded globular projection for use in celestial maps about the year 1000. Centuries later, as Europe entered its Age of Discovery, the demand for world maps increased rapidly, sparking a vast experimentation with diverse map projections. Globular projections were one category that received early attention, with inventions by Roger Bacon in the 13th century, Petrus Apianus in the 16th century, and also in the 16th century by French Jesuit priest Georges Fournier. In 1660, Giovanni Battista Nicolosi, a Sicilian chaplain in Rome, reinvented Al-Biruni's projection as a modification of Fournier's first projection. It is unlikely Nicolosi knew of al-Biruni's work, and Nicolosi's name is the one usually associated with the projection.
Nicolosi published a set of maps on the projection, one of the world in two hemispheres, and one each for the five known continents. Maps using the same projection appeared occasionally over the ensuing centuries, becoming relatively common in the 19th century as the stereographic projection fell out of common use for this purpose. Use of the Nicolosi projection continued into the early 20th century. It is rarely seen today.
Description
The construction of the Nicolosi globular projection is fairly simple with compasses and straightedge.
Given a bounding circle to fit the map into, the poles are placed at the top and bottom of the circle, and the central meridian of the desired hemisphere is drawn as a straight vertical diameter between them.
The equator is drawn as a straight horizontal diameter.
Each remaining meridian is drawn as a circular arc going through both poles and the equator,
such that meridians are equally spaced along the equator.
Each remaining parallel is also drawn as a circular arc from the left edge through the central meridian to the right edge of the circle,
such that the parallels are equally spaced around the perimeter of the circle and also equally spaced along the central meridian.
A hemisphere shown with the Nicolosi globular projection closely resembles a hemisphere shown with the azimuthal equidistant projection centered on the same point.
In both projections of that hemisphere, the meridians are equally spaced along the equator, and the parallels are equally spaced along the central meridian and also equally spaced along the perimeter of the circle.
Nicolosi developed the projection as a drafting technique. Translating that into mathematical formulae yields:
Here, is the latitude, is the longitude, is the central longitude for the hemisphere, and is the radius of the globe to be projected.
In the formula for , the sign takes the sign of , i.e. take the positive root if is positive, or the negative root if is negative.
In the formula for , the sign takes the opposite sign of , i.e. take the positive root if is negative, or the negative root if is positive.
Under certain circumstances, the full formulae fail. Use the following formulae instead:
When ,
When ,
When ,
When ,
See also
List of map projections
References
External links
Image of Nicolosi's world map at the David Rumsey collection.
Map projections | Nicolosi globular projection | [
"Mathematics"
] | 785 | [
"Map projections",
"Coordinate systems"
] |
58,499,837 | https://en.wikipedia.org/wiki/Methenmadinone%20acetate | Methenmadinone acetate (MMA), also known as methylenedehydroacetoxyprogesterone (MDAP) and sold under the brand names Superlutin and Antigest, is a progestin medication which was developed in Czechoslovakia in the 1960s. It is the C17α acetate ester of methenmadinone.
MMA given orally shows about 13-fold the progestogenic activity of parenteral progesterone in animal bioassays.
Analogues of methenmadinone acetate include methenmadinone caproate (MMC), which was studied in combination with estradiol valerate as a combined injectable contraceptive (tentative brand name Lutofollin); chlormethenmadinone acetate (chlorsuperlutin; SCH-12600; 6-chloro-MMA), which has been used in combination with mestranol in birth control pills (brand names Biogest, Sterolibrin, Antigest B) and in veterinary medicine (brand name Agelin); bromethenmadinone acetate (bromsuperlutin; 6-bromo-MMA), which was assessed but was never marketed; and melengestrol acetate (methylsuperlutin; 6-methyl-MMA), which is used in veterinary medicine.
See also
List of progestogen esters § Esters of 17α-hydroxyprogesterone derivatives
16-Methylene-17α-hydroxyprogesterone acetate
References
Abandoned drugs
Acetate esters
Diketones
Pregnanes
Progestogen esters
Progestogens
Vinylidene compounds | Methenmadinone acetate | [
"Chemistry"
] | 361 | [
"Drug safety",
"Abandoned drugs"
] |
58,500,310 | https://en.wikipedia.org/wiki/Caroline%20A.%20Masiello | Caroline Masiello is a biogeochemist who develops tools to better understand the cycling and fate of globally relevant elemental cycles. She is a professor at Rice University in the Department of Earth, Environmental and Planetary Sciences and holds joint appointments in the Chemistry and Biochemistry Departments. Masiello was elected as a Fellow of the Geological Society of America in 2017. She currently leads an interdisciplinary team of scientists who are developing microbial sensors for earth system science.
Early life and education
Masiello moved several times as a child, attending high school in Indiana, Pennsylvania. Here she attended the Pennsylvania's Governor's School for Sciences. She majored in Physics and Math at Earlham College, and graduated with honors in 1991. She went onto earn a Master of Science in Environmental Sciences from the University of North Carolina at Chapel Hill in 1993 and a Master of Science in Physical Chemistry from the University of California, Irvine in 1996. While at UC-Irvine Masiello worked with Ellen R.M. Druffel, developing biogeochemical tools to examine carbon pools. Her thesis, Radiocarbon measurements of black carbon in sediments of a small river, examined the temporal shifts of the particulate and dissolved carbon exported from the Santa Clara River, CA. using Δ14C, earning her a Ph.D. in Earth System Science from UC-Irvine in 1999.
Career and research
After her graduate studies, Masiello worked as a Postdoctoral Scholar at the Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory (1999-2002) and with the Geography Department at the University of California, Santa Barbara (2002-2004). She was appointed to the faculty at Rice University in 2004 where she serves as a member of the Department of Earth, Environmental and Planetary Sciences.
Masiello's research focuses on developing tools that allow her to understand how elements are cycling around the planet, this includes tools that track how cells communicate to one another (e.g.) to others that allow us to follow organic carbon pools from the atmosphere to mountain slopes to the ocean (eg.). In particular, her group focuses on how carbon is stored, transformed, and transported in and through soils, rivers, and oceans; thus it has contributed to basic and applied research in the fields of organic geochemistry and biogeochemistry. In particular her work has advanced our knowledge of black carbon (and biochar) within both aquatic and terrestrial environments (e.g.). For her “outstanding contributions into understanding the role of organic carbon in soils across Earth’s surface, which impacts a wide range of geoscience and other fields, such as agriculture and climate change” she was recognized as a Fellow by the Geological Society of America in 2017.
Masiello currently leads a team of scientists, including biochemist Jonathan Silberg and microbiologist Matthew Bennett, working to develop microbial biosensors that will help us improve our ability to manage our landscape to preserve and promote ecosystem services such as carbon sequestration and nitrate removal by alerting us to key biogeochemical processes.
Masiello's work has garnered support from a number of funding sources, including the National Science Foundation, U.S. Department of Energy, W.M. Keck Foundation, and more (e.g.).
Awards
2022 UCI Physical Sciences Alumni Hall of Fame
2017 Fellow Geological Society of America
2002-2003 American Fellow, American Association of University Women
Outreach
Masiello merges her research with teaching and outreach. Her lab hosts K-12 teachers from local Houston schools, working collaboratively with them, to develop earth science curricular materials.
References
Living people
Place of birth missing (living people)
Year of birth missing (living people)
Earlham College alumni
University of North Carolina at Chapel Hill alumni
University of California, Irvine alumni
Biogeochemists
Fellows of the Geological Society of America
American geologists
American women geologists
Fellows of the American Association of University Women
21st-century American women | Caroline A. Masiello | [
"Chemistry"
] | 815 | [
"Geochemists",
"Biogeochemistry",
"Biogeochemists"
] |
58,500,469 | https://en.wikipedia.org/wiki/Bacterial%20secretion%20system | Bacterial secretion systems are protein complexes present on the cell membranes of bacteria for secretion of substances. Specifically, they are the cellular devices used by pathogenic bacteria to secrete their virulence factors (mainly of proteins) to invade the host cells. They can be classified into different types based on their specific structure, composition and activity. Generally, proteins can be secreted through two different processes. One process is a one-step mechanism in which proteins from the cytoplasm of bacteria are transported and delivered directly through the cell membrane into the host cell. Another involves a two-step activity in which the proteins are first transported out of the inner cell membrane, then deposited in the periplasm, and finally through the outer cell membrane into the host cell.
These major differences can be distinguished between Gram-negative diderm bacteria and Gram-positive monoderm bacteria. But the classification is by no means clear and complete. There are at least eight types specific to Gram-negative bacteria, four to Gram-positive bacteria, while two are common to both. In addition, there is appreciable difference between diderm bacteria with lipopolysaccharide on the outer membrane (diderm-LPS) and those with mycolic acid (diderm-mycolate).
Export pathways
The export pathway is responsible for crossing the inner cell membrane in diderms, and the only cell membrane in monoderms.
Sec system
The general secretion (Sec) involves secretion of unfolded proteins that first remain inside the cells. In Gram-negative bacteria, the secreted protein is sent to either the inner membrane or the periplasm. But in Gram-positive bacteria, the protein can stay in the cell or is mostly transported out of the bacteria using other secretion systems. Among Gram-negative bacteria, Escherichia coli, Vibrio cholerae, Klebsiella pneumoniae, and Yersinia enterocolitica use the Sec system. Staphylococcus aureus and Listeria monocytogenes are Gram-positive bacteria that use the Sec system.
The Sec system utilises two different pathways for secretion: the SecA and signal recognition particle (SRP) pathways. SecA is an ATPase motor protein and has many related proteins including SecD, SecE, SecF, SegG, SecM, and SecY. SRP is a ribonucleoprotein (protein-RNA complex) that recognizes and targets specific proteins to the endoplasmic reticulum in eukaryotes and to the cell membrane in prokaryotes. The two pathways require different molecular chaperones and ultimately use a protein-transporting channel SecYEG for transporting the proteins across the inner cell membrane. In the SecA pathway, SecB acts as a chaperone, helping protein transport to the periplasm after complete synthesis of the peptide chains. Whereas in the SRP pathway, YidC is the chaperone, and transport proteins to the cell membrane while they are still undergoing peptide synthesis. In Escherichia coli, inner membrane proteins are mainly targeted by the SRP pathway and outer membrane or periplasmic proteins are targeted by the SecA pathway. However, a recent selective ribosome profiling study suggest that inner membrane proteins with large periplasmic loops are targeted by the SecA pathway.
SecA or post-translational pathway
Proteins are synthesised in ribosomes by a process of serially adding amino acids, called translation. In SecA pathway, a chaperone trigger factor (TF) first bind to the exposed N-terminal signal sequence of the peptide chain. As elongation of peptide chain continues, TF is replaced by SecB. SecB specifically maintains the peptide in an unfolded state, and aids in the binding of SecA. The complex can then bind to SecYEG, by which SecA is activated by binding with ATP. Driven by ATP energy, SecA pushes the protein through the secYEG channel. SecD/F complex also helps in the pulling of the protein from the other side of the cell membrane.
In recent years, the SecA pathway has also been suggested to have a co-translational mechanism, meaning that the polypeptide would be targeted directly by SecA during its synthesis.
SRP pathway
In this pathway, SRP competes with TF and binds to the N-terminal signal sequence. Proteins from inner membrane stops the process of chain elongation. The SRP then binds to a membrane receptor, FtsY. The peptide chain-SRP-FtsY complex is then transported to SecY, where peptide elongation resumes.
Tat system
The twin-arginine translocation pathway (Tat pathway) is similar to Sec in the process of protein secretion, however, it sends proteins only in their folded (tertiary) state. It is used by all types of bacteria, as well as archaea, and chloroplasts and mitochondria of plants. In bacteria, the Tat system exports proteins from the cytoplasm across the inner cell membrane; whereas in chloroplasts, it is present in the thylakoid membrane where it aids the import of proteins from the stroma. Tat proteins are highly variable in different bacteria and are classified into three major types, namely TatA, TatB, and TatC. For example, while there are only two functional Tat proteins in Bacillus subtilis, there can be over a hundred in Streptomyces coelicolor. Signal peptides that can recognise the Tat proteins are characterised by a consensus motif Ser/Thr-Arg-Arg-X-Phe-Leu-Lys (where X can be any polar amino acid). It is the two successive arginines from which the name twin arginine translocation came from. Replacement of any of the arginine leads to slow down or failure of secretion.
Wss/Esx pathway
The Wss/Esx (ESAT-6 system) pathway is sometimes called a type VII secretion system (T7SS) despite being an export pathway. It is present in Gram-positive bacteria (as WSS) and Mycobacteria (as Esx in all diderm-mycolates) such as M. tuberculosis, M. bovis, Streptomyces coelicolor and S. aureus. It is also called T7b system in Bacillus subtilis and S. aureus. It is composed of two basic components: a membrane-bound hexameric ATPase that is member of the FtsK/SpoIIIE protein family, and any one of the EsxA/EsxB-related protein such as EsaA, EsaD, EsxB, EsxD, as well as Ess system (EssA, EssB, and EsxC found in S. aureus). EsxA and EsxB belong to a superfamily of WXG100 proteins that form dimeric helical hairpins.
In S. aureus, T7SS secretes a large toxin called EsaD, which is a member of nuclease enzymes. EsaD is made harmless (detoxified) during its biosynthesis with the help of its counterpart antitoxin EsaG. The EsaD-EsaG complex then binds with EsaE. The EsaE portion binds to EssC, which is an enzyme ATPase of the T7SS complex. During secretion, EsaG is left in the cytoplasm, and only EsaD and EsaE are secreted together. But in some strains of S. aureus, EsaD is not produced, but two copies of EsaG-like proteins are formed instead. This might explain the occurrence of T7SS in non-pathogenic species such as B. subtilis and S. coelicolor.
Secretion systems
The secretion systems are responsible for crossing the outer cell membrane or both membranes in diderms. The current nomenclature applies to diderm-LPS only, as nothing is known about what diderm-mycolate bacteria use to cross their outer membrane.
Type I
Type I secretion system (T1SS or TOSS) is found in Gram-negative bacteria. It depends on chaperone activity using Hly and Tol proteins. The system activates as a signal sequence HlyA binds HlyB on the cell membrane. This signal sequence is an ABC transporter. The HlyAB complex activates HlyD which uncoils and moves to the outer cell membrane. The terminal signal is recognised by TolC in the inner membrane. The HlyA is secreted out of the outer membrane through a tunnel-like protein channel.
T1SS transports various molecules including ions, carbohydrates, drugs, proteins. The secreted molecules vary in size from the small Escherichia coli peptide colicin V, which is 10 kDa, to the Pseudomonas fluorescens cell adhesion protein LapA, which is 520 kDa. Among the most well known molecules are RTX toxins and lipase enzymes.
Type II
Type II (T2SS) secretion system depends on the Sec or Tat system for initial secretion inside the bacterial cell. From the periplasm, proteins are secreted out of the outer membrane secretins. Secretins are multimeric (12–14 subunits) complex of pore-forming proteins. Secretin is supported by 10–15 other inner and outer membrane proteins to constitute the complete secretion apparatus.
Type III
Type III secretion system (T3SS or TTSS) is structurally similar and related to the basal body of bacterial flagella. Seen in some of the most virulent Gram-negative bacteria such as Salmonella, Shigella, Yersinia, Vibrio, it is used to inject toxic proteins into eukaryotic cells. The structure of T3SS is often described as an injectisome or needle/syringe-like apparatus. Discovered in Yersinia pestis, it was found that T3SS can inject toxins directly from the bacterial cytoplasm into the cytoplasm of its host's cells.
Type IV
Type IV secretion system (T4SS or TFSS) is related to bacterial conjugation system, by which different bacteria can exchange their DNAs. The participating bacteria can be of the same or different Gram-negative bacterial species. It can transport single proteins, as well as protein-protein and DNA-protein complexes. Secretion is transferred directly from the recipient cell through the cell membranes. Agrobacterium tumefaciens, from which it was originally discovered, uses this system to send the T-DNA portion of the Ti plasmid into plant cells, in which a crown gall (tumor) is produced as a result. Helicobacter pylori uses it for delivering CagA into gastric epithelial cells, to induce gastric cancer. Bordetella pertussis, the causative bacterium of whooping cough, secretes its pertussis toxin partly through T4SS. Legionella pneumophila that causes legionellosis (Legionnaires' disease) has a T4SS called icm/dot (intracellular multiplication/defect in organelle trafficking genes) that transport many bacterial proteins into its eukaryotic host. More recently, it has been shown that the phytopathogen Xanthomonas citri utilizes its T4SS to secrete effectors that are lethal to other bacterial species, thus placing this system as a major fitness determinant of interspecies bacterial competition. The prototypic Type IVA secretion system is the VirB complex of Agrobacterium tumefaciens.
Type V
Type V secretion systems (T5SS) are different from other secretion systems in that they secrete themselves and only involves the outer cell membrane. For secreted protein to pass through the inner cell membrane, T5SS depends on Sec system. They have a β-barrel domain, which inserts into the outer cell membrane and forms a channel that can transport secreted protein along with it. For this activity, they are also called the autotransporter systems. When the secreted proteins are exposed outside, the autotransporters are cut off (cleaved), releasing the protein from the β-barrel domain. An example of autotransporter is the Trimeric Autotransporter Adhesins.
Type VI
Type VI secretion systems (T6SS) were discovered by the team of John Mekalanos at the Harvard Medical School in 2006 from Vibrio cholerae and Pseudomonas aeruginosa. They were recognised when mutations in the Vibrio Cholerae Hcp and VrgG genes caused diminished virulence and pathogenicity. In addition to their classic role as the pathogenicity factor, T6SS are also involved in defense against simple eukaryotic predators and in inter-bacteria interactions. The gene for T6SS form a gene cluster that consists of more than 15 genes. Hcp and VgrG genes are the most universal genes. Structural similarity of T6SS with the tail spike of the T4 phage suggest that the process of infection is similar to that of the phage.
Type VII
The T7SS of diderm-LPS bacteria is the chaperone-usher pathway.
In diderm-mycolate bacteria this secretion system is the ESAT-6.
Type VIII
The T8SS of diderm-LPS bacteria is the extracellular nucleation-precipitation pathway.
Type IX
Type IX secretion systems (T9SS) are found regularly in the Fibrobacteres-Chlorobi-Bacteroidetes lineage of bacteria, where member species include an outer membrane. The system is involved variably in one type of gliding motility, in the proper targeting of certain virulence factors to the cell surface, and the degradation of complex of biopolymers. T9SS has also been known as Por (porphyrin accumulation on the cell surface) secretion, after the oral pathogen Porphyromonas gingivalis. At least sixteen structural components of the system have been described, including PorU, a protein-sorting transpeptidase that removes the C-terminal sorting signal from cargo proteins and mediates their attachment instead to lipopolysaccharide.
References
Cellular processes
Membrane biology
Prokaryotic cell anatomy
Secretion | Bacterial secretion system | [
"Chemistry",
"Biology"
] | 3,058 | [
"Membrane biology",
"Cellular processes",
"Molecular biology"
] |
58,500,983 | https://en.wikipedia.org/wiki/Methenmadinone | Methenmadinone, also known as deacetylsuperlutin or as 16-methylene-6-dehydro-17α-hydroxyprogesterone, is a pregnane steroid which was never marketed. It is a parent compound of methenmadinone acetate (the C17α acetate ester), melengestrol (the C6 methyl derivative), and chlormethenmadinone (the C6 chloro derivative).
References
Abandoned drugs
Tertiary alcohols
Diketones
Pregnanes
Progestogens
Vinylidene compounds | Methenmadinone | [
"Chemistry"
] | 128 | [
"Drug safety",
"Abandoned drugs"
] |
58,501,072 | https://en.wikipedia.org/wiki/Chlormethenmadinone%20acetate | Chlormethenmadinone acetate (CMMA), also known as chlorsuperlutin, is a progestin medication which was developed in Czechoslovakia in the 1960s. It has been used in combination with mestranol in birth control pills under the brand names Biogest, Sterolibrin, and Antigest B, and in veterinary medicine under the brand name Agelin. Analogues of CMMA include bromethenmadinone acetate (bromsuperlutin), which was assessed but was never marketed, and melengestrol acetate (methylsuperlutin), which is used in veterinary medicine.
See also
List of progestogen esters § Esters of 17α-hydroxyprogesterone derivatives
16-Methylene-17α-hydroxyprogesterone acetate
References
Abandoned drugs
Acetate esters
Organochlorides
Diketones
Pregnanes
Progestogen esters
Progestogens
Veterinary drugs
Vinylidene compounds | Chlormethenmadinone acetate | [
"Chemistry"
] | 212 | [
"Drug safety",
"Abandoned drugs"
] |
58,503,126 | https://en.wikipedia.org/wiki/Methenmadinone%20caproate | Methenmadinone caproate (MMC, also known as superlutin caproate) is a progestin medication which was developed in Czechoslovakia in the 1960s and was studied for potential use in combined injectable contraceptives in the 1970s but was never marketed. It was studied as a combined injectable contraceptive in combination with estradiol valerate at doses of 60 mg and 10 mg, respectively, once a month by intramuscular injection (tentative brand name Lutofollin). MMC is the C17α caproate (hexanoate) ester of methenmadinone and an analogue of methenmadinone acetate (MMA; superlutin). In addition to MMA, analogues of MMC include chlormadinone caproate, gestonorone caproate, hydroxyprogesterone caproate, medroxyprogesterone caproate, and megestrol caproate.
See also
Estradiol valerate/methenmadinone caproate
List of progestogen esters § Esters of 17α-hydroxyprogesterone derivatives
References
Abandoned drugs
Caproate esters
Diketones
Pregnanes
Progestogen esters
Progestogens | Methenmadinone caproate | [
"Chemistry"
] | 270 | [
"Drug safety",
"Abandoned drugs"
] |
58,503,642 | https://en.wikipedia.org/wiki/16-Methylene-17%CE%B1-hydroxyprogesterone%20acetate | 16-Methylene-17α-hydroxyprogesterone acetate is a progestin of the 17α-hydroxyprogesterone group which was never marketed. Given orally, it shows about 2.5-fold the progestogenic activity of parenteral progesterone in animal bioassays. It is a parent compound of the following clinically used progestins:
Chlormethenmadinone acetate (6-chloro-16-methylene-17α-hydroxy-Δ6-progesterone acetate)
Melengestrol acetate (6-methyl-16-methylene-17α-hydroxy-Δ6-progesterone acetate)
Methenmadinone acetate (16-methylene-17α-hydroxy-Δ6-progesterone acetate)
Segesterone acetate (16-methylene-17α-hydroxy-19-norprogesterone acetate)
References
Abandoned drugs
Acetate esters
Diketones
Pregnanes
Progestogens
Vinylidene compounds | 16-Methylene-17α-hydroxyprogesterone acetate | [
"Chemistry"
] | 234 | [
"Drug safety",
"Abandoned drugs"
] |
73,833,765 | https://en.wikipedia.org/wiki/Mycena%20subcyanocephala | Mycena subcyanocephala is a species of fungi, which has its habitat in the tropical parts of Taiwan. It has been spotted twelve times. Mycena subcyanocephala is noted for its small size, with buttons about 1 mm tall. The species belongs to the Mycenaceae family, with Mycena interrupta being its closest known relative.
Mycena subcyanocephala should not be regarded as edible. Neither substantial nor psychedelic, it could also embody the toxic chemical muscarine.
Mycena subcyanocephala is a species of fungus that grows on wood in the tropical parts of Taiwan. It's currently the smallest know mushroom in the world, with caps about 1 mm tall and a white color with a pale blue tone. It belongs to the Mycenaceae family and the section Spinosae. It has 2-spored basidia, smooth round-headed cheilocystidia, and thin-walled pileiocystidia and caulocystidia.
Description
Mycena subcyanocephala is a lignicolous species of section Spinosae, having tomentulose fruitbodies, a white cap with pale blue tone, a thin-walled pileiocystidia and caulocystidia, smooth round-headed cheilocystidia, inamyloid basidiospores, and 2-spored basidia.
References
subcyanocephala
Fungi described in 2019
Fungus species | Mycena subcyanocephala | [
"Biology"
] | 312 | [
"Fungus stubs",
"Fungi",
"Fungus species"
] |
73,834,772 | https://en.wikipedia.org/wiki/Dioxygen%20monofluoride | Dioxygen monofluoride is a binary inorganic compound radical of fluorine and oxygen with the chemical formula . The compound is stable only at low temperature. This is one of many known oxygen fluorides.
Synthesis
Thermal decomposition of dioxygen difluoride:
Photolysis of and dilute in argon:
Physical properties
Dioxygen monofluoride is a strong oxidizing agent, can be prepared in the coaxial reactor.
References
Oxygen fluorides
Free radicals
Nonmetal halides
Oxidizing agents | Dioxygen monofluoride | [
"Chemistry",
"Biology"
] | 114 | [
"Oxygen fluorides",
"Redox",
"Free radicals",
"Oxidizing agents",
"Senescence",
"Biomolecules"
] |
73,835,845 | https://en.wikipedia.org/wiki/Ana%20P%C3%A9rez-Neira | Ana Isabel Pérez-Neira (born 1967) is a Spanish telecommunications engineer, a professor in the Signal Theory and Communication Department of the Polytechnic University of Catalonia, the former vice rector for research of the university, the director of the Centre Tecnológic de Telecomunicacions de Catalunya, and the coordinator of the European Space Agency Networks of Excellence on Satellite Communications. Her research concerns multibeam satellite communications, beamforming, and the signal processing needed in that application.
Education and career
Pérez-Neira was born in 1967 in Zaragoza. She studied electrical engineering, earning a bachelor's degree in 1989, and then a master's degree in 1991 at University Ramon Llull. She completed a Ph.D. in 1995 at the Polytechnic University of Catalonia, working there with .
She was appointed as a full professor at the Polytechnic University of Catalonia in 2006, and served as vice rector for research from 2010 to 2014. She was appointed as director of the Centre Tecnológic de Telecomunicacions de Catalunya in 2021.
Recognition
Pérez-Neira was named an IEEE Fellow, in the 2020 class of fellows, "for contributions to signal processing for satellite communications and systems". She became a full member of the in 2021. In 2022 she was named a EURASIP Fellow by the European Association for Signal Processing, "for her contributions to signal processing for satellite and wireless communication systems".
References
External links
1967 births
Living people
Spanish electrical engineers
Spanish women engineers
Telecommunications engineers
Women electrical engineers
University Ramon Llull alumni
Academic staff of the Polytechnic University of Catalonia
Fellows of the IEEE | Ana Pérez-Neira | [
"Engineering"
] | 328 | [
"Telecommunications engineering",
"Telecommunications engineers"
] |
73,836,434 | https://en.wikipedia.org/wiki/Calvert%20and%20Porter%20Woods | The Calvert and Porter Woods Nature Preserve is a 40-acre old-growth forest located in Montgomery County, Indiana, near Crawfordsville. Identified as a surviving fragment of virgin Central Hardwood forest, a woodland type that largely vanished in the 1800s, it was designated as a National Natural Landmark in 1974.
Description
The old-growth Calvert and Porter Woods Nature Preserve is located on the Tipton Till Plain, a morphological biome that contains mesic soil types and a significant moisture gradient for the preservation of numerous microecosystems. The U.S. National Park Service characterizes the woodlot as a significant tree-mature location for the great blue heron.
Most old-growth forest has vanished from Indiana. Long usage during the Industrial Revolution has ensured that most large trees have been cut down for timber or firewood. On this woodlot, several surviving trees measure over five feet (60 inches) in diameter. The Indiana Division of Forestry classifies the Calvert and Porter land parcel as “40 acres of one of the highest quality old growth woods in the state.”
The Calvert and Porter Woods Nature Preserve is owned by the Indiana Department of Natural Resources (IDNR). As of 2023 IDNR has not, however, taken active steps to encourage visitation to the woods. There is no direct road access to the property parcel, no trails have been built on the woodlot, and prior permission is required for property access. Periodic opportunities create rare, but recurring, opportunities for those who are interested in signing up for a group hike led by a guide with site-oriented experience.
References
National Natural Landmarks in Indiana
Old-growth forests
Protected areas of Montgomery County, Indiana
Forests of Indiana | Calvert and Porter Woods | [
"Biology"
] | 339 | [
"Old-growth forests",
"Ecosystems"
] |
73,837,085 | https://en.wikipedia.org/wiki/Nzambici | Nzambici (also called Nzambi) is the eternal God of Essence, as well as Moon, Earth and Sky Mother in Bakongo religion. She is also the female counterpart of the Kongo creator god, Nzambi Mpungu.
History
By the 17th century, Nzambici's importance seems to have diminished. Oral tradition from the period states that Nzambi Mpungu was surrounded by lesser spirits, including Nzambici. There is consensus among historians that this reduction of nature spirits to lesser spirits was due to the Portuguese influence of monotheism and their shunning of "idols." Whereas Nzambici and Nzambi Mpungu were once "the marvel of marvels," Nzambi Mpungu began to exist independently of Nzambici, and was seen as a supreme Creator God, similar to the Christian God of Portuguese colonizers.
Kongo cosmology
Oral tradition states that in the beginning, time, place and space did not exist. There was only a circular void, called mbûngi. One day, the "Sovereign Master" Nzambi Mpungu summoned a spark of fire, called kalûnga, which gained energy and burned until its flames filled mbungi. When it became too hot, it hurled pieces of debris outside of the circle. Those pieces traveled far and wide in all directions until they came to stop. When they cooled off, they were stars and planets, which formed the universe. Nzambi Mpungu then became Kalûnga, the god of fire and change.
Nzambici and Nzambi Mpungu
Wanting to expand his creation, some oral traditions say that Nzambi Mpungu crafted his female counterpart named Nzambici, the god of essence. Other oral traditions say Nzambici always existed alongside Nzambi Mpungu as an eternal goddess in her own right.
Nevertheless, they lived as one, watching over all they had made. That was until Nzambici stole some of his fire, or kalûnga, and gained power of her own. To punish her, Nzambi Mpungu is said to have created the earth and sent her there. But unable to stay away from her for too long, he returned to earth and married Nzambici. On earth, they created the waters, the land and the animals. She subsequently became "the god on earth, the great princess, the mother of all the animals, the one who promises her daughter to the animal who shall bring her the fire from heaven."
Nzambici and Nzambi then created the first Kongo person, or muntu. Nzambici also became the great mystery of the earth, "the mother of a beautiful daughter, gives mankind all laws, ordinances, arts, games, and musical instruments." She "settles quarrels between animals, and in the stories giving her decision is embedded an immense amount of Fjort law." To guide man, Nzambici and Nzambi Mpungu created nature spiritssimbi, nkisi, nkita, and kilunduand separated the physical world, called Nseke, from the spiritual world, called Mpémba, with a boundary of water, called the kalûnga line. A mystical forest, mfinda, ran between the worlds, where nature spirits and the ancestors could travel from one world to the other and advise the living. Nzambici and Nzambi Mpungu withdrew from the earth and took their place in the heavens, choosing to no longer interact with man. Man knew Nzambici as the earth and moon and Nzambi Mpungu as the sun. Because of the duality of Nzambici and Nzambi, the Kongo people believed that the right side of the body was male, while the left side was believed to be female.
See also
Bunzi
Kongo cosmogram
Kongo religion
Lunar deity
Simbi
Sky deity
References
African deities
African goddesses
Animal goddesses
Bantu deities
Bantu religion
Creator deities
Creator goddesses
Earth deities
Earth goddesses
Kongo culture
Lunar deities
Lunar goddesses
Sky and weather deities
Sky and weather goddesses
Traditional African religions
Tutelary deities
Tutelary goddesses
Kongo religion | Nzambici | [
"Physics"
] | 884 | [
"Weather",
"Sky and weather deities",
"Physical phenomena"
] |
73,837,093 | https://en.wikipedia.org/wiki/North%20Island%20little%20spotted%20kiwi | The North Island little spotted kiwi or North Island little grey kiwi (Apteryx owenii iredalei) is an extinct subspecies of the little spotted kiwi that was native to the North Island, New Zealand. It was described by Gregory Mathews in 1935. Most subsequent authors do not recognise it or any other subspecies of Apteryx owenii.
The North Island little spotted kiwi went extinct sometime in the late 19th century for unknown reasons; most likely from introduced invasive species such as stoats, feral cats, and other related species, or from human activity in the region. Two specimens were collected in the 1880s, being the only known remnants left.
References
Apteryx
Bird extinctions since 1500
Birds of the North Island
Controversial bird taxa
Extinct birds of New Zealand
Extinct flightless birds
Subspecies | North Island little spotted kiwi | [
"Biology"
] | 163 | [
"Biological hypotheses",
"Controversial bird taxa",
"Controversial taxa"
] |
73,837,678 | https://en.wikipedia.org/wiki/Mono-N-protected%20amino%20acids | Mono-N-protected amino acid (MPAA) is a bifunctional ligand that plays a key role in C–H functionalizations by accelerating the reaction rate and imparting specified chirality into the product. Amino acids are ideal building blocks for chiral ligand synthesis due to the cost, accessibility, large variety, solubility, and inherent chirality. Naturally occurring amino acids are transformed into chiral MPAA ligands that, upon coordination to metal complexes, allow reactions to occur that are otherwise energetically unfavorable. Great strides in the development of MPAA ligands over the past two decades have led to the integral role that enantioselective catalysis now plays in complex organic synthesis.
History and development
In the past century, there has been much research into the development of effective chiral catalysts due to its great potential in organic synthesis. In the 1960s, cyclometalation reactions including C(sp2)–H and C(sp3)–H cleavage were pioneered by Kleiman, Dubeck, Cope, and Siekman. A decade later, Shaw discovered that inorganic acetate salts promoted otherwise difficult cyclopalladations. To build off of this work, Sokolov focused on developing chiral, enantioenriched metallacyles and proposed the concerted metal-deprotonation (CMD) mechanism.
Despite this foundation of discoveries, enantioselective catalysis for C–H functionalization continued to lack in efficiency oand selectivity for desired chiral product formation. In 2008, Jin-Quan Yu reported the first MPAA ligands, showcasing their use in enantioselective activation of C(sp2)–H and C(sp3)–H bonds. Initial synthesis occurred by reacting the nucleophilic amino acid in base with a highly electrophilic acyl chloride resulting in one new amide bond formation. Upon addition of acyl chloride, most resulting groups off of the nitrogen were common protecting groups used in organic synthesis, hence mono-N-protected. Taking advantage of the weak coordination of amides and carboxylates with Pd-complexes, this enantioselective catalysis requires the MPAA ligand to allow the reaction to proceed and determine the product chirality, minimizing side reactions that may occur without the ligand. Since the initial discovery, Yu has continued to pioneer the field by expanding the substrate scope, increasing functional group tolerance, and developing ligand variations.
Mechanism
After iterative computational and experimental studies, the internal amidate mechanism was proposed in collaboration of Wu, Yu, and Houk. In the proposed mechanism, the trimeric Pd-precatalyst converts to the mono-Pd complex with coordination to solvent and the bidentate MPAA ligand. Mass spectrometry results reveal this active catalyst which forms favorably with the stabilizing dianionic MPAA ligand as computations suggest.
The key intermediate step of these cyclometalation reactions involves the metal-mediated cleavage of the C–H bond and simultaneous formation of the metal–C bond of the substrate. Upon addition of substrate, the N-acyl motif acts as an internal proton acceptor in the concerted metal-deprotonation (CMD) of the transition state for this inner-sphere process. According to this model, the rate and selectivity of the C–H functionalization are impacted by the basicity of the MPAA ligand. The resulting experimental data of steric and electronic alteration of the MPAA ligands align with this model. In 2023, the first experimental observations to support the proposed mechanism were reported, which were previously unattainable due to the lack of well-defined isolated palladium-MPAA complexes.
Ligand variations
Since the initial MPAA ligand report, many variations of bifunctional ligands derived from amino acids have been developed. Bidentate MPAQ (mono-protected amino quinoline) ligands were introduced in the application of β-methylene C–H bonds in aliphatic amides. The highly successful MPAO (mono-protected amino oxazoline) ligand allowed for C(sp3)–H functionalization via arylation of α-methyls, borylation of cyclobutyl carboxylic amides, and boronic cross coupling of alkyl amines. MPAAM (mono-protected aminoalkyl amine) ligands were used in enantioselective C(sp3)–H arylations of free aliphatic acids without the need for exogenous directing groups. Variations of the MPAAThio (mono-protected aminoalkyl thioether) ligands have been use in olefination of free carboxylic acids and arylation, carbonylation, and olefination of free aliphatic amines.
Expanding the reaction substrate scope to non-directed C(sp2)–H bonds, pyridone ligands were developed to functionalize arenes and heteroarenes which proved to be particularly useful in late-state derivatization of bioactive compounds such as estrone, caffeine, and camptothecin. Many analogues of the pyridine-pyridone (azine-pyridone) ligands were developed and used in the C(sp2)–H hydroxylation of (hetero)arenes and the dehydrogenation of methylene C(sp3)–H bonds on alkyl free acids.
Applications in total synthesis
The development of MPAA ligands enabled and improved the synthesis of many complex natural products. Examples include Arnottin 1, Aspercylide B, Berkelic Acid, Boletopsin 11, Danshenspiroketallactone, Delavatine A, Herbindole B/cis-Trikentrin A, Hongoquercin A, Incarviatone A, Indoxamycin, Kedarcidin/Neocarzinostatin, Kinamycin
, Lithospermic Acid, M1 PAMs, and VS-548. In the formation of indoxamycin cores, MPAA ligand assisted C–H functionalization introduces high complexity via intramolecular ortho olefination.
The use of C–H functionalization in the synthesis of lithospheric acid exemplifies the site- and stereoselective capabilities of using MPAA ligands in these reactions. As the penultimate step, the intermolecular C–H olefination introduces almost double the complexity into the compound enabling the highly convergent synthesis.
References
Ligands
Amino acids | Mono-N-protected amino acids | [
"Chemistry"
] | 1,391 | [
"Amino acids",
"Biomolecules by chemical classification",
"Ligands",
"Coordination chemistry"
] |
73,838,740 | https://en.wikipedia.org/wiki/Chethika%20Gunasiri | Chethika Gunasiri is a Sri Lankan environmental scientist and researcher. She is well known for her sustainability related efforts especially related to Colombo Wetland Management Strategy. She has often spoken about the importance of wetlands for a sustainable Colombo and she has raised awareness among public about the critical role played by wetlands for the sustainability and to attain sustainable urban future.
Career
She completed her Ph.D. in the field of Sustainability Science at the United Nations University in Japan. She also pursued her Master's degree in Science in the field of Earth Science from the Chinese Culture University in Taiwan. She also completed her MBA from the University of Sri Jayewardenepura and also obtained her Bachelor's degree in Zoology from the University of Colombo.
She also currently serving as an environmental scientist at the Sri Lanka Land Development Corporation. She also prominently works to address concerns related to restoration, management and wise use of urban wetlands to comply with sustainable city development. She has attained over a decade of experience in the field of urban ecosystem management. She was also instrumental by pioneering as an expert in preparing the Colombo Wetland Management Strategy and the application for the Ramsar Wetland City Accreditation for Colombo City.
She also served in various other capacities including South Asia Regional Representative of the Wetland Link International-Asia Steering Committee, member of the Institute of Environmental Professionals Sri Lanka (IEPSL), and as an Assistant Secretary and a council member of the same organisation.
She was invited as a guest speaker in January 2023 to deliver Wildlife and Nature Protection Society (WNPS) lecture under the theme of "Living in the only wetland capital in the world" at the Bandaranaike Memorial International Conference Hall.
References
Living people
Sri Lankan academics
Sinhalese people
Sri Lankan scientists
Sri Lankan women activists
Sri Lankan women environmentalists
Sri Lankan women academics
Sri Lankan women scientists
Chinese Culture University alumni
United Nations University alumni
Alumni of the University of Colombo
Alumni of the University of Sri Jayewardenepura
People from Colombo
Year of birth missing (living people)
21st-century Sri Lankan women
Sri Lankan earth scientists
Women hydrologists
Sustainability scientists | Chethika Gunasiri | [
"Environmental_science"
] | 416 | [
"Sustainability scientists",
"Environmental scientists"
] |
73,839,744 | https://en.wikipedia.org/wiki/LP%20791-18 | LP 791-18 (TOI-736) is a cool M dwarf star in the constellation Crater, located away from Earth.
The star is one of the smallest known to host exoplanets. In 2019 two exoplanets in transit around it were announced by TESS, and a third planet was discovered in Spitzer Space Telescope data in 2023.
Planetary system
The innermost planet, b, is a super-Earth and the outermost planet, c, is a mini-Neptune. They were discovered together in 2019. The middle planet, d, is an Earth-mass world discovered in 2023. It may potentially be tidally heated by interactions with planet c, which would lead to abundant volcanoes similar to Jupiter's moon Io. As the planet d is in the inner edge of the habitable zone, liquid water could condense on the side of the planet that faces away from the host star.
In 2021 planet c was suggested for atmospheric analysis by the James Webb Space Telescope.
References
Crater (constellation)
M-type main-sequence stars
Planetary systems with three confirmed planets
736
J11024596-1624222
181804752 | LP 791-18 | [
"Astronomy"
] | 240 | [
"Crater (constellation)",
"Constellations"
] |
73,842,156 | https://en.wikipedia.org/wiki/Pentaoxygen%20difluoride | Pentaoxygen difluoride is a binary inorganic compound of fluorine and oxygen with the chemical formula . The compound is one of many known oxygen fluorides.
Synthesis
The compound can be prepared by electric discharges through the — mixture of the certain molar ratio at 60 to 77K. The ratio is predicted to be 5:2.
Physical properties
Pentaoxygen difluoride is an oxidizing agent. At 90K, the compound looks like a reddish-brown liquid and as an oil at 77 K.
At 77K, the compound is insoluble in liquid , soluble in liquid and . At 65K, it is soluble in liquid .
References
Oxygen fluorides
Nonmetal halides
Oxidizing agents | Pentaoxygen difluoride | [
"Chemistry"
] | 155 | [
"Oxygen fluorides",
"Redox",
"Inorganic compounds",
"Oxidizing agents",
"Inorganic compound stubs"
] |
73,842,164 | https://en.wikipedia.org/wiki/Alan%20Quayle | Alan Quayle was a British chemist and mass spectrometrist.
Career
During the 1950s, Quayle worked at the research laboratories of the Shell Refining & Marketing Co. Ltd at the Thornton Research Centre. Quayle spent time working at the Shell oil refinery in Deer Park, Texas laboratory with Jack O'Neill in the USA, where he also attended meetings of the ASTM Committee E-14 at the Pittsburgh Analytical Conference. Much of his early work involved the development of "high molecular weight" analysis up to m/z 800 using the MS2 with a heated inlet. He later worked at Aston University in its Department of Molecular Sciences.
Quayle was a founding member of the British Mass Spectrometry Society and its 3rd Chair during 1966–67. He was also a key member of the Hydrocarbon Research Group of the Institute of Petroleum. He was the first editor of the International Journal of Mass Spectrometry.
Personal life
Alan Quayle was born on 28 July 1923 in Middlesbrough, the only child of John Quayle, an elementary teacher, and Mary Elizabeth (née Emery).
He married Thelma Marie Lindop in Chester in 1952. They had two sons: Andrew John and William Duncan (who died aged 18).
Alan Quayle died on 2 January 1994 in Mollington, Cheshire; he was survived by his wife, son and two grandsons. Thelma died on 5 March 2010.
References
British chemists
Mass spectrometrists
People associated with Aston University
Shell plc people | Alan Quayle | [
"Physics",
"Chemistry"
] | 306 | [
"Biochemists",
"Mass spectrometry",
"Spectrum (physical sciences)",
"Mass spectrometrists"
] |
73,842,226 | https://en.wikipedia.org/wiki/Habitability%20of%20F-type%20main-sequence%20star%20systems | The habitability of F-type main-sequence star (or yellow-white dwarf) systems is disputed due to the shorter lifetimes (3–8 Gyrs as opposed to 9–15 Gyrs for G stars) and higher levels of UV radiation. Indeed, F0 stars (7,400 K, 1.6 M☉︎, 1.7 R☉︎, ~7 L☉︎) are considered by many scientists as the hottest and most massive stars capable of supporting habitable planets. A planet orbiting an F-type star at the Earth boundary within the HZ would receive 2.5 (F9 star) to 7.1 (F0 star) times the UV that Earth gets from the sun.
Overview
One study on planets and their moons orbiting stars from F5 to F9.5 concluded that exoplanets/moons around exoplanets orbiting in habitable zones of F-type stars would receive excessive UV damage as compared to the Earth. If half a billion years is assumed as the amount of time it took for life to evolve, then the highest spectral type considerable for life-bearing planets' stars is ~B8 (12,300 K, 3.3 M☉︎, 2.8 R☉︎, ~160 L☉︎), making F-type stars habitable in terms of lifetime. Still, it took 3 billion years to establish complexity, ruling out all stars hotter than A9, and more than so to establish a technological civilization, ruling out all stars hotter than F2. Putting lifetime concerns aside, life on primordial Earth likely started in an underwater (and far underwater) environment anyway, and the water keeps the UV from reaching life-forms. In fact, it is possible that more UV could jumpstart the genesis and evolution of life, fulfilling main-sequence deadlines. In addition, hotter stars would have wider habitable zones (2.0–3.7 AU for an F0 star and 1.1–2.2 AU for an F8 star as opposed to 0.8–1.7 AU for the Solar System), which would be another advantage of looking for habitable planets around F- and A-type stars. If UV does indeed prove to be primarily problematic, then according to, a planet orbiting at the Early Mars limit around an F8 star would actually be better off than Earth, receiving only 95% of the Earth's UV irradiation, and atmospheric attenuation would decrease even a Venus-like (in terms of stellar flux) planet around an F0 star's UV irradiation to less than 1/4 that of Earth. The best case would be an Earth-like planet at the Early Mars limit with attenuation around an F8-type star, where UV irradiance is 3.7% Earth's.
Evolutionary changes
According to, the greatest change in UV irradiance occurs in a planet orbiting an F0 star with >1.5 M☉︎, as opposed to an F8 or F9 star with ≤1.2 M☉︎. The most dangerous phase in a star's life for potentially habitable planets orbiting it would be the earliest, between the star's formation and its 500 Mya-milestone, especially emphasized (again) on the more massive side of the F-star spectrum. The study even concludes that in some cases (i.e. a planet at the outer edge of the habitable zone around an old F5 or F8 star), a planet can receive less, not more, UV than an exact Earth twin would.
Frequency
According to the Kepler data, M-type stars supposedly had more Earth-sized planets than larger, Sunlike (where the term is broad, meaning any FGK star) stars. However, in recent years, the Gaia space telescope has exposed Kepler's flaws, making it apparent that Earth-sized planets around red dwarfs are no more common than around FGK stars. As a result, the habitability of F-type stars is not impaired by the overall frequency of Earth-sized planets around them. However, it does show that Earth-size planets should be extremely uncommon (<0.1%) in the habitable zones of their stars. So, instead of exoplanets, some studies focus mainly on exomoons orbiting Jupiter-like planets that fall within the habitable zone. Alternatively, a study done by NASA with the same telescope gave a result saying that up to 50% of stars with temperatures between 4,300 (K6) and 7,300 (F0) K had habitable planets, and the number increased to 75% when the optimistic habitable zone was used.
The habitability of F-type systems may be impaired, though, by the fact that they make up only 3% of the stars in the Milky way, compared to 6–8% for G-types, 12–13% for K-types, and ~70% for red dwarfs. Further study is required to make decisive conclusions about the frequency of habitable planets around F-type stars.
Examples
, there are no known potentially habitable exoplanets around F-type stars, but some unconfirmed Kepler candidates many be potentially habitable, including KOI-4878.01, KOI-7040.01, KOI-6676.01, KOI-5202.01, and KOI-5236.01. Upsilon Andromedae has a Jupiter-like planet in the habitable zone and could therefore have habitable exomoons. HD 10647 also has such a planet, which has a mass of >0.94 Jupiter masses and orbits at the outer frontier of the habitable zone.
KOI-4878.01
KOI-4878.01 is a potentially habitable exoplanet candidate orbiting an F8-type star. It is Earth-sized, with a period of 449 days and a semi-major axis of 1.137 AU. The equilibrium temperature is , and it gets just 1.04 times the light that Earth gets from the Sun. It could be the most Earth-like planet ever found (ESI = 0.98) if it is confirmed, despite its hotter and more massive star (stellar properties are not taken into account in ESI calculation). With a purely watery composition, the mass would be ~4 Mars masses (0.4 Earths), and with a pure iron composition, the mass would be 3 Earths.
Upsilon Andromedae system
Upsilon Andromedae is another F8-type star, and the primary star in a wide binary system, in the constellation of Andromeda. It has 3 confirmed Jovian planets, and Upsilon Andromedae d orbits in the star's extended habitable zone on a 1267-day year. It orbits near the outer edge, at 2.5 AU, and has a minimum mass of 4.6 Jupiters. The habitability potential is therefore in possible Earth-like exomoons and not in the planet itself. It was the first multiple-planet system to be found around a main-sequence star (as well as, consequently, an F star) and is shown to be dynamically stable in all scenarios.
See also
Habitability of red dwarf systems
Habitability of K-type main-sequence star systems
Habitability of yellow dwarf systems
Earth analog
List of Kepler exoplanet candidates in the habitable zone
List of potentially habitable exoplanets
References
Stars
F-type main-sequence stars
Exoplanets
Planetary habitability
Astrobiology | Habitability of F-type main-sequence star systems | [
"Astronomy",
"Biology"
] | 1,570 | [
"Origin of life",
"Stars",
"Speculative evolution",
"Astrobiology",
"Biological hypotheses",
"Astronomical objects",
"Astronomical sub-disciplines"
] |
73,842,466 | https://en.wikipedia.org/wiki/Dinema%20platysomum | The flagellated alga Dinema platysomum, synonym Anisonema platysomum, is the first eukaryote in which magnetotactic structures have been discovered. Monje & Baran (2004) describe how this euglenoid alga stores magnetite in a similar way that already discovered magnetotactic bacteria do. It has been shown that the cells contain magnetite particles aligned with the longitudinal axis of the alga, and each magnetite chain is a permanent dipole. The observed magnetic momentum of the cell has been estimated to be 1000 times stronger than those of typical magnetotactic bacteria.
The species was first described in 1939 as Anisonema platysomum, and transferred to the genus Dinema in 2000.
References
Euglenozoa | Dinema platysomum | [
"Biology"
] | 165 | [
"Algae stubs",
"Algae"
] |
73,842,544 | https://en.wikipedia.org/wiki/Archibald%20Winterbottom | Archibald Winterbottom (1814–1884) was a British cotton cloth merchant who is best known for becoming the largest producer of bookcloth and tracing cloth in the world. Bookcloth became the dominant bookbinding material in the early 19th century, which was much cheaper and easier to work with than leather, revolutionising the manufacture and distribution of books.
Early life
Winterbottom was born in Linthwaite in the heart of the West Riding of Yorkshire, the son of a third generation wool cloth merchant, William Whitehead Winterbottom (1771–1842) and Isabella (née Dickson, 1784–1849). Not long after, the family moved to the civil parish of Saddleworth, where Winterbottom, at the age of 15, left home in search of his fortune. He reportedly promised his father that, when he obtained a position, he would "do his utmost to succeed".
Early career
In 1829, Winterbottom is said to have walked the 12 miles to Manchester, presumably seeking an apprenticeship, beginning his working life as a clerk with the largest cotton merchants in Manchester (Henry Bannerman & Sons). He remained with Bannerman's for the next twenty-three years, where he learned how to refine cloth to the highest degree and developed different finishes that could be applied to plain cloth. At the age of nineteen, he was appointed to manage their Bradford accounts and to run their Silesia department, patenting a silvery finish lining, which became known as Dacians. Winterbottom was made a partner at Bannerman's aged thirty, which he held for the next nine years.
Social reformer
Manchester was at the heart of the cotton industry in Britain during the 19th century, which was a labour-intensive sector at a time when half of the workforce were children. In 1845, Winterbottom married Helen Woolley, whose family came from a Unitarian tradition. At the same time, he became actively involved in the Lancashire Public School Association (LPSA) founded in 1847, which was dominated by Unitarians. By 1852, Winterbottom formed part of a delegation of the National Public School Association (NPA) to present a draft bill to Lord John Russell at 10 Downing Street "for the establishment of non-denominational free schools in England and Wales". He remained active within the NPA, listed as secretary to the general committee on education in 1857, but by 1862, the NPA had achieved some of what it had set out to achieve and was dissolved. Winterbottom went on to work with the newly formed Manchester Educational Aid Society campaigning for compulsory primary education. He spent the rest of his life actively involved in improving child welfare, creating new schools and changing legislation to protect children.
Entrepreneur
By 1851, Winterbottom had a successful career working at Henry Bannerman & Sons, living in a prosperous neighbourhood in the northwest of Manchester. He had been gaining experience in working the machinery needed to create the highest quality bookcloth featuring innovations of his own and, in the same year, he presented his latest bookcloth samples to the Great Exhibition at The Crystal Palace. The following year, Winterbottom retired from the Bannerman partnership to start his own business, taking with him the Dacian patent. A few months later, he opened an office in the city centre at Mosley Street, as well as a small factory containing two calendering machines in the Ancoats district, later opening offices in Bradford as well as London, growing a business that thrived for over a hundred years. Initially, he experimented with new designs, winning a prize medal at an exhibition in London in 1862. With competition increasing in the bookcloth sector, Winterbottom argued for improved standards in the way that goods are labelled, a cause championed by his previous partners at Bannerman's.
An embargo on cotton exports from America at the outbreak of the American Civil War triggered a crisis in Lancashire, resulting in mass redundancies and social unrest, attributable as much to mis-management as to supply challenges. The embargo created a five-fold increase in cotton prices at a time when the market was already flooded with finished goods, causing it to collapse. Winterbottom had managed to continue trading throughout the crisis, which left him with large debts. By 1869, he was forced to report the failure of his business to his creditors, who met to agree refinancing, accepting an offer of 50% market value on his assets to raise fresh capital.
Supported by his Bradford creditors, Winterbottom sought to increase market share and searched for larger premises. In 1874, he purchased and refurbished Victoria Mills, making him the leading cloth producer of bookcloth and tracing cloth in England (ibid.), opening new storage premises at 43, Fountain Road adjacent to the warehouse occupied by Bannerman & Sons in the city centre. In 1879, Winterbottom created an Imperial Trade Mark for tracing cloth, which became the global benchmark for quality. The Victoria Mills complex was gradually expanded, making him the largest producer of bookcloth and tracing cloth in the world. In the same year, he brought his two surviving sons into the business and in 1881, a new office was established in Newton Street, an address that was to become synonymous with the bookcloth industry. By 1882, he was in a position to pay back all his creditors with full compound interest. Two years later, he died quite suddenly at his house in Pendleton, but not before he had assured his own legacy.
Legacy
Winterbottom created a business that lasted over a hundred years, which found a place on the bookshelves of every middle-class household in Britain, while providing the means for educating those less fortunate. Much of that wealth generation was in creating patents, but as orders increased (4,000 customers) and the volume of different patterns soared (50,000), the staggering number of permutations prompted Winterbottom to create an innovative indexed codification system. The code tracked customer details, orders, stocks, materials, invoicing and delivery. By creating index tables in much the same way as relational tables are structured in databases today, meant that customers only had to register their names and addresses once (unique identifier) and the system took care of the orders. Once staff had been trained in its application, inventories were augmented, suppliers were paid and orders were delivered on time. An attempt was made to replace Winterbottom's system with an expensive computer in the 1950s but the attempt failed and the company was forced to revert to his original code (ibid.).
Arguably Winterbottom's greatest but least remembered legacy was his commitment to child education. He was directly and indirectly involved in the reformation of public education in England and Wales through legislative reform. It was also through his work with children and young men that he came in to contact with luminaries of the time, such as the poet Charles Swain, who dedicated his last book of poetry to him. Schools in Manchester then and today, such as the Manchester Free School and the Manchester District School for Orphan and Necessitous Children of Warehouseman and Clerks, owed their existence in part to the dedication of men like Winterbottom. He was president of the Unitarian Home Missionary College the year before he died.
There were two occasions in Winterbottom's life, however, when his actions did achieve national attention, prompting scores of newspaper articles that had little to do with Winterbottom's own notability. Firstly in 1863, when he challenged the Earl of Derby’s right to deny public access to a well and an ancient footpath that went across Derby's land. The ruling in Winterbottom's favour was so popular in Manchester that he gave lecture tours for entertainment. The second was in 1882, when Winterbottom paid back his creditors, which was repeated a year later when the same creditors presented him with an extravagant 3-foot high silver centre-piece, featuring Sabrina, the Goddess of the River Severn, flanked by a pair of massive candelabra.
Winterbottom was interred in the family vault at the Unitarian Chapel in Stand.
References and notes
Notes
1814 births
1884 deaths
Cloth merchants
Bookbinders
Industrialists
British businesspeople
Cotton industry in England
British social reformers
English Unitarians
Bookbinding
Book arts
Book design
Book publishing
Crafts
Graphic design
Paper art
Print production
People from Manchester
Education in Manchester | Archibald Winterbottom | [
"Engineering"
] | 1,703 | [
"Book design",
"Design"
] |
73,842,570 | https://en.wikipedia.org/wiki/HD%20169853 | HD 169853, also known as HR 6910 or rarely 9 G. Coronae Australis, is a solitary star located in the southern constellation Corona Australis. It is faintly visible to the naked eye as a white-hued point of light with an apparent magnitude of 5.62. Gaia DR3 parallax measurements imply a distance of 391 light years, and it is currently approaching the Solar System with a heliocentric radial velocity of . At its current distance, HD 169853's brightness is diminished by 0.36 magnitudes due to extinction from interstellar dust and it has an absolute magnitude of +0.13.
HD 169853 has a stellar classification of A2mA2-F0, indicating that it is an Am star with the calcium H lines of an A2 star and the metallic lines of an F0 star. Abt and Morell (1995) give a class of A3 III, indicating that the object is instead an evolved A-type giant star with no chemical peculiarities. A paper published in late 1987 found that HD 169853 had an overabundance of silicon, manganese, strontium, and barium.
The object has 2.09 times the mass of the Sun and a slightly enlarged radius of . It radiates 60.7 times the luminosity of the Sun from its photosphere at an effective temperature of . It has a near solar metallicity at (Fe/H) = −0.01 and it is estimated to be 585 million years old, having completed 80% of its main sequence lifetime. Like many chemically peculiar stars, HD 169853 rotates rather slowly, having a projected rotational velocity of .
References
Am stars
Corona Australis
Coronae Australis, 9
CD-39 12626
169853
090541
6910
A-type giants | HD 169853 | [
"Astronomy"
] | 386 | [
"Corona Australis",
"Constellations"
] |
73,842,573 | https://en.wikipedia.org/wiki/Hexaoxygen%20difluoride | Hexaoxygen difluoride is a binary inorganic compound of fluorine and oxygen with the chemical formula . The compound is one of many known oxygen fluorides.
Synthesis
The compound can be prepared by electric discharges through the — mixture of the certain molar ratio at 60 to 77 K. The ratio is predicted to be 6:2.
Physical properties
Hexaoxygen difluoride is an oxidizing agent. At 60 K, the compound looks like a dark-brown crystalline solid. If slowly warmed, it decomposes to lower oxygen fluorides and ozone. If quickly warmed to 90 K, it explodes, creating and .
References
Oxygen fluorides
Nonmetal halides
Oxidizing agents | Hexaoxygen difluoride | [
"Chemistry"
] | 152 | [
"Oxygen fluorides",
"Redox",
"Oxidizing agents"
] |
73,842,665 | https://en.wikipedia.org/wiki/Stewartson%20layer | In fluid dynamics, a Stewartson layer is a thin cylindrical shear layer that connects two differentially rotating regions in the radial direction, namely the inside and outside the cylinder. The Stewartson layer, typically, also connects different Ekman boundary layers in the axial direction. The layer was first identified by Ian Proudman and was first described by Keith Stewartson. This layer should be compared with the Ekman layer which occurs near solid boundaries.
Structure
The Stewartson layer is not elementary but possesses a complex structure and emerges when the relevant Ekman number is ; here is the kinematic viscosity, and are the characteristic scales for the angular speed and length. The fundamental balance that occurs in the Stewartson shear layer is between Coriolis forces and viscous forces.
Spherical geometry
For simplicity, consider the example of two concentric spheres that rotate about a common axis with slightly different angular velocity. The fluid domain corresponds to the annular region. In this problem, the Stewartson layer emerges as a cylinder circumscribing the inner sphere with its generators lying parallel to the rotation axis. Outside , the fluid rotates as a solid body with a speed that of the outer sphere. Inside (in the annular region), again the fluid rotates as a solid body, except near the inner and outer sphere walls, where Ekman boundary layers of thickness are set up that help adjusting the flow to transition from uniform rotation to their respective rotating values on the solid walls. Across , there is a jump in the azimuthal velocity and on , there is an axial flow connecting the two Ekman layers. The structure of is the Stewartson layer.
The Stewartson layer consists of two outer layers, one on the inner side of with a thicknesses and one on the outer side of with a thickness ; these outer layers flank a thin inner layer of thickness . The differential rotation between inside and outside is smoothed out in the outer layers (primarily in the outer layer lying on the outer side of ). The adjustment of azimuthal motion in the outer layers induces secondary axial flow. The inner layer becomes necessary partly to accommodate this induced axial motion and partly to accommodate the transport of flow between one Ekman boundary layer to the other one (from the Ekman layer on the faster-rotating sphere to the slower one). Note that the thickness of the Ekman layer is , which is much smaller than the inner Stewartson layer. In the inner layer, change in the azimuthal velocity is very small, because the outer layers are already smoothed out jump in the azimuthal velocity. In addition, the outer layers (again primarily in the outler layer lying outer side of the cylinder) also transport axially flow from the fast rotating sphere to slower one.
Cylindrical geometry
In cylindrical geometries, the thickness of both the two outer layers is and the thickness of inner layer is .
See also
Ekman layer
References
Flow regimes
Fluid dynamics | Stewartson layer | [
"Chemistry",
"Engineering"
] | 598 | [
"Piping",
"Chemical engineering",
"Flow regimes",
"Fluid dynamics"
] |
73,843,019 | https://en.wikipedia.org/wiki/Tungsten%20hexabromide | Tungsten hexabromide, also known as tungsten(VI) bromide, is a chemical compound of tungsten and bromine with the formula WBr6. It is an air-sensitive dark grey powder that decomposes above 200 °C to tungsten(V) bromide and bromine.
Production and reactions
Tungsten hexabromide is mainly produced by the reaction of metallic tungsten and bromine at temperatures around 100 °C in a nitrogen atmosphere:
W + 3 Br2 → WBr6
Another method of producing this compound is by the reaction of tungsten hexacarbonyl and bromine at room temperature, releasing carbon monoxide. It can also be produced by the metathesis reaction of boron tribromide and tungsten hexachloride.
WBr6 is reduced with elemental antimony at elevated temperatrues, consecutively producing, WBr5, WBr4, W4Br10, W5Br12, then finally WBr2 at 350 °C. This reaction produces antimony tribromide as a side product. Any of these bromides can be reverted to the hexabromide by oxidation with bromine at 160 °C.
Tungsten hexabromide is hydrolyzed in water, producing tungsten pentoxide and releasing bromine.
Tungsten(VI) oxytetrabromide is produced by the reaction of tungsten hexabromide and tungsten(VI) oxide:
2 WBr6 + WO3 → 3 WOBr4
Structure
The trigonal crystal structure of WBr6 consists of isolated WBr6 octahedra and is isostructural with α-WCl6.
References
Tungsten halides
Bromides | Tungsten hexabromide | [
"Chemistry"
] | 352 | [
"Bromides",
"Salts"
] |
73,843,117 | https://en.wikipedia.org/wiki/G79.29%2B0.46 | G79.29+0.46 is a luminous blue variable star candidate located in the Cygnus X star formation region. In the infrared and at radio wavelengths a prominent circular nebula can be seen. This nebula was formed by past mass-loss episodes of the LBV candidate.
G79.29+0.46 was first reported as a suspected LBV by Higgs, Wendker & Landecker in 1993 with the DRAO Synthesis Telescope, which identified a nebula around a star that was a wind-blown shell. As an LBV candidate, it has a spectrum with many emission lines, H-alpha being the strongest. The spectrum is similar to other LBVs and Be supergiants. The strength of the H-alpha line suggest very dense winds around this star. The star is currently losing mass at a rate of /year and it is surrounded by a dusty envelope with a temperature of 40 to . The star is considered only a candidate LBV because it has not shown variability in the optical or near-infrared over 20 years. It has been suggested that it is a LBV in the quiescent stage.
From radio and infrared images a detached shell can be seen that shows evidence of two mass-loss episodes. This shell has a mass of and a radius of 0.66 parsecs, and it contains carbon monoxide and ammonia.
Gallery
References
Cygnus (constellation)
B-type supergiants
IRAS 20298+4011
Luminous blue variables
J20314228+4021591 | G79.29+0.46 | [
"Astronomy"
] | 316 | [
"Cygnus (constellation)",
"Constellations"
] |
73,843,734 | https://en.wikipedia.org/wiki/Downtown%20Circle | Downtown Circle is a proposed megastructure in Dubai, United Arab Emirates. The project is designed by ZNera Space, an architecture firm based in Dubai. Downtown Circle would be a 550-meter-tall ring that would encircle the Burj Khalifa, the world's tallest skyscraper. The ring would be 3,000 meters in circumference and would house residential, commercial, and public spaces.
The project is designed to be sustainable and self-sufficient. The ring would be powered by renewable energy and would have a green belt that would provide food and oxygen for the residents. The ring would also have a system of canals and waterfalls that would help to cool the air and provide a habitat for wildlife.
References
Proposed buildings and structures in Dubai
Proposed arcologies | Downtown Circle | [
"Technology"
] | 159 | [
"Exploratory engineering",
"Proposed arcologies"
] |
73,844,425 | https://en.wikipedia.org/wiki/Ricing%20stick | A ricing stick ( (singular), (plural)), also known as a flail, knocking stick, or rice knocker, is an agricultural hand tool used for threshing wild rice.
Ricing sticks have been traditionally used by Anishinaabe peoples of the Great Lakes region. The ricing sticks are used to harvest wild-growing rice by knocking the ripened grains off of the stalks of rice. This harvesting is typically performed by canoe—as the plants grow partially submerged in shallow water—and the sticks are used to knock the rice into the canoe or a collection vessel. Any stick can be used, but ricing sticks are normally tapered, blunt sticks, sometimes with a flattened end, with a thicker end, sometimes lined in cloth, meant to be held in the hand. Ricing sticks can be used two at a time, one in each hand, while a companion rows the canoe.
While the tool has ancient roots, it continues to be utilized in modern society, even by non-indigenous people, and use of ricing sticks on public or tribal lands is often regulated. For example, in Minnesota, wild rice on public land can be harvested only using hand-operated ricing sticks which must be "round, smooth wood no longer than 30 inches and weigh no more than one pound." According to the 1854 Treaty Authority Ceded Territory Code, ricing sticks must be “round, smooth cedar, no longer than 32-inch,” while in Wisconsin, they can be up to 38 inches.
References
External links
Roger LaBine, of the Lake Superior Chippewa, demonstrates making ricing sticks at the 2017 Great Lakes Intertribal Summit.
Anishinaabe culture
Mechanical hand tools
Threshing tools
Wands | Ricing stick | [
"Physics"
] | 355 | [
"Mechanics",
"Mechanical hand tools"
] |
73,845,645 | https://en.wikipedia.org/wiki/HD%20170521 | HD 170521, also known as HR 6937 or rarely 12 G. Coronae Australis, is a solitary star located in the southern constellation Corona Australis. It is faintly visible to the naked eye as an orange-hued point of light with an apparent magnitude of 5.69. The object is located relatively far at a distance of approximately 1,500 light years based on Gaia DR3 parallax measurements, and it is receding with a heliocentric radial velocity of . At its current distance, HD 170521's brightness is heavily diminished by 0.46 magnitudes due to extinction from interstellar dust and it has an absolute magnitude of −1.90.
HD 170521 has a stellar classification of K2 III, indicating that it is an evolved red giant. It has 1.55 times the mass of the Sun but it has expanded to 78.6 times the Sun's radius. The object radiates 934 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of . HD 170521 is metal deficient with an iron abundance only 32.4% that of the Sun (Fe/H) = −0.49 and it spins modestly with a projected rotational velocity of .
References
K-type giants
Corona Australis
Coronae Australis, 12
CD-43 12600
170521
090842
6937 | HD 170521 | [
"Astronomy"
] | 288 | [
"Corona Australis",
"Constellations"
] |
73,847,522 | https://en.wikipedia.org/wiki/SN%202023ixf | SN 2023ixf is a type II-L (core collapse) supernova located in the Pinwheel Galaxy. It was first observed on 19 May 2023 by Kōichi Itagaki and immediately classified as a type II supernova. Initial magnitude at discovery was 14.9. After discovery, the Zwicky Transient Facility project found a precovery image of the supernova at magnitude 15.87 two days before discovery. The supernova was about 21 million light-years from Earth and is expected to have left behind either a neutron star or black hole, based on current stellar evolution models.
The supernova is located near a prominent HII region, NGC 5461, in an outer spiral arm of the bright galaxy.
By 22 May 2023, SN 2023ixf had brightened to about magnitude 11. It could be seen in telescopes as small as and remained visible with backyard telescopes for several months. The supernova started to fade around 10 June 2023.
The last supernova that close to Earth occurred 9 years previously: SN 2014J in Messier 82, roughly 12 million light-years from Earth.
Before becoming a supernova, the progenitor star is believed to have been a supergiant with an absolute magnitude in the near-infrared (814nm) of MF814W = –4.66.
Image gallery
References
See also
SN 1987A
External links
Supernova Discovered in Nearby Spiral Galaxy M101, Astronomy Picture of the Day (NASA)
AAVSO: magnitude plot
Supernovae
Astronomical objects discovered in 2023
Discoveries by Koichi Itagaki
Ursa Major
2023 in outer space | SN 2023ixf | [
"Chemistry",
"Astronomy"
] | 339 | [
"Supernovae",
"Ursa Major",
"Astronomical events",
"Constellations",
"Explosions"
] |
73,847,727 | https://en.wikipedia.org/wiki/Kiguma%20Jack%20Murata | Kiguma Jack Murata (December 29, 1909 MarysvilleDecember 27, 2001 Sacramento) was a Japanese American geochemist of the U.S. Geological Survey who served as Scientist-in-Charge of the Hawaiian Volcano Observatory from 1958 to 1960. Murata was a fellow of the Mineralogical Society of America and the Geological Society of America, and served on the Standards Committee of the Geochemical Society in 1957.
In 1980, Murata received a Distinguished Service Award from the U.S. Department of the Interior in 1980, the department's highest honor.
Personal life
Murata married Fumiko Elizabeth Kozono in 1938. She was also known as Elizabeth F. Murata by the time of her death.
Kiguma Murata's son, Stephen K. Murata, won an Air Force Commendation Medal in 1967.
Mineralogy
The mineral murataite-(Y), commonly known as murataite, was named for him in 1974. The tree species Ochroma murata (genus Ochroma) is also named for him. Murata was also involved in naming minerals, such as faheyite, which he, with Marie Louise Lindberg, named for Joseph John Fahey.
Memberships
During the 1940s and 50s, he was a member of the Optical Society of America, as well as a member of both the Hawaiian Academy of Science around 1960 and the Society of Economic Paleontologists and Mineralogists in the 1970s.
Impact
Murata died 2001 in Sacramento, California to pneumonia, following a stroke months earlier.
After his death, he was extended a tribute in the House of Representatives by Robert T. Matsui, who described him as "one of the most distinguished scientists and Government employees among Americans of Japanese ancestry in this country."
References
Further reading
(describes much of Murata's work during this period)
People from Marysville, California
People from Sacramento, California
United States Geological Survey personnel
1909 births
2001 deaths
Fellows of the Geological Society of America
American geochemists
Fellows of the Mineralogical Society of America
American academics of Japanese descent
American scientists of Asian descent | Kiguma Jack Murata | [
"Chemistry"
] | 429 | [
"Geochemists",
"American geochemists"
] |
73,848,606 | https://en.wikipedia.org/wiki/I%20%E2%80%93%20Shih%20Liu | I – Shih Liu (1943) is a Taiwanese civil engineer. He teaches at the Institute of Mathematics of Federal University of Rio de Janeiro.
Education
I – Shih Liu studied at the National Taiwan University and graduated with a diploma in 1972. He continued his studies at the Johns Hopkins University (JHU) where he received his doctorate in applied mechanics in 1972 under the supervision of Ingo Müller.
Academic life
He became assistant professor at the National Taiwan University in 1965, teaching and research assistant at the Johns Hopkins University in 1967, post-doctoral fellow in 1972 and professor at Federal University of Rio de Janeiro (UFRJ) in 1972. He became visiting professor at Carnegie Mellon University in 1976–1977, at University of Bologna in 1982, 1986, at University of Berlin in 1990-1991 and Nagoya Institute of Technology in 2004. He also became visiting professor at Texas A&M University in 2006–2007, at College of Earth Sciences National Central University in 2012 and director pro-tempore at UFRJ in 2000–2002. Since 1972, he has more than 50 mathematical research articles published in peer-reviewed international journals. He is married with one son.
Research areas
His work deals with continuum mechanics, thermodynamics, relativistic mechanics, rigid body mechanics, elastodynamics, mechanics of deformable bodies, constitutive theories, entropy principle, Lagrange multipliers.
Writings
Introduction to Continuum Mechanics, Springer-Verlag, 2002
with Jose Merodio e Giuseppe Saccomandi: Constitutive Theories: Basic Principles Chapter 6 in Continuum Mechanics, in Encyclopedia of Life Support Systems (EOLSS) Developed under the auspices of the UNESCO Publications, 2009
A Continuum Mechanics Primer Lecture Note - On Constitutive Theories of Materials, 2010
Introduction to Continuum Mechanics Lecture Note, 2018
Elementary Tensor Analysis Lecture Note, 2018
Selected publications
Liu, I.-S. (1972): Method of Lagrange Multipliers for Exploitation of the Entropy Principle | Arch. Rat. Mech. Anal. (ARMA); vol. 46, no. 2, pp. 131–148. Doi:10.1007/BF00250688
Liu, I.-S. (1973): (a) A Non-Simple Heat-Conducting Fluid | Arch. Rat. Mech. Anal. (ARMA); vol. 50, no. 1, pp. 26–33. Doi:10.1007/BF00251292
Liu, I.-S. (1973): (b) On the Entropy Supply in a Classical and a Relativistic Fluid | Arch. Rat. Mech. Anal. (ARMA); vol. 50, no. 2, pp. 111–117. Doi:10.1007/BF00249878
Liu, I.-S. (1982): On Representations of Anisotropic Invariants | Int. J. Eng. Sci. (IJES); vol. 20, no. 10, pp. 1099–1109. Doi:10.1016/0020-7225(82)90092-1
Liu, I.-S. (1996): On Entropy Flux-Heat Flux Relation in Thermodynamics with Lagrange Multipliers | Cont. Mech. Thermodyn. (CMT); vol. 8, pp. 247–256. Doi:10.1007/s001610050042
Liu, I.-S. (2001): Constitutive Equations of Extended Thermodynamics from a Hybrid Pair of Generator Functions | Cont. Mech. Thermodyn. (CMT); vol. 13, no. 1, pp. 25–39. Doi:10.1007/s001610100040
Liu, I.-S. (2003): On the Transformation Property of the Deformation Gradient under a Change of Frame | J. Elast. (JELAS); vol. 71, no. 1, pp. 73–80. Doi:10.1023/B:ELAS.0000005548.36767.e7
Liu, I.-S. (2005): Further Remarks on Euclidean Objectivity and the Principle of Material Frame-Indifference | Cont. Mech. Thermodyn. (CMT); vol. 17, no. 2, pp. 125–133. Doi:10.1007/s00161-004-0191-3
Liu, I.-S. (2008): Entropy Flux Relation for Viscoelastic Bodies | J. Elast. (JELAS); vol. 90, no. 3, pp. 259–270. doi:10.1007/s10659-007-9142-0
Liu, I.-S. (2009): (a) Constitutive Theory of Anisotropic Rigid Heat Conductors | J. Math. Phys. (JMP); vol. 50, no. 8, pp. 083506. Doi:10.1063/1.3190487
Liu, I.-S. (2009): (b) On Entropy Flux of Transversely-Isotropic Elastic Bodies | J. Elast. (JELAS); vol. 96, no. 2, pp. 97–104. Doi:10.1007/s10659-009-9200-x
Liu, I.-S. (2011): Successive Linear Approximation for Boundary Value Problems of Nonlinear Elasticity in Relative-Descriptional Formulation | Int. J. Eng. Sci. (IJES); vol. 49, no. 7, pp. 635–645. Doi:10.1016/j.ijengsci.2011.02.006
Liu, I.-S. (2012): A Note on the Mooney–Rivlin Material Model | Continuum Mech. Thermodyn.; vol. 24, no. 4, pp. 583–590. Doi:10.1007/s00161-011-0197-6
Liu, I.-S. (2014): A Solid-Fluid Mixture Theory of Porous Media | Int. J. Eng. Sci. (IJES); vol. 84, pp. 133–146.Doi:10.1016/j.ijengsci.2014.07.002
External links
Home page at DMM
References
1943 births
Living people
National Taiwan University alumni
Taiwanese civil engineers
Johns Hopkins University alumni
Thermodynamicists
Academic staff of the Federal University of Rio de Janeiro | I – Shih Liu | [
"Physics",
"Chemistry"
] | 1,406 | [
"Thermodynamics",
"Thermodynamicists"
] |
73,848,861 | https://en.wikipedia.org/wiki/Aurosilane | Aurosilane is an inorganic compound with a chemical formula of SiAu4. In this compound, gold acts as an electron acceptor with a valence of -1. Aurosilane has been isolated as a type of gold silane. Its unit cell parameters are a=5.658, c=5.605 A. The LUMO and the four Si-Au bonding orbitals of SiAu4 are similar to those of SiH4.
In addition, silicon can also form other compounds with gold such as Si3Au3
References
External reading
Gold(−I) compounds
Inorganic silicon compounds
Silanes
Transition metal silicides | Aurosilane | [
"Chemistry"
] | 135 | [
"Inorganic silicon compounds",
"Inorganic compounds",
"Inorganic compound stubs"
] |
73,850,710 | https://en.wikipedia.org/wiki/Rocks%20at%20Freyr | The Rocks at Freÿr form a large rock mass on the right bank of Meuse, between Waulsort and Anseremme in (Wallonia Belgium). Its walls of varying gradients and roughness make it a privileged climbing place in Belgium. The site is listed in the Wallonia's Major Heritage and the Natura 2000 network
Location and access
The Namur-Dinant road. After crossing Dinant, exit towards Beauraing. At Anseremme, you have two choices: either go up the N95 (direction of Beauraing) for about 4 km to the tableland of Freÿr, or after passing under the railway bridge, take the small street on the right (Av Amand de Mendieta), then go around the port of the Yacht Club of Anseremme and continue for one km to reach a path located between the Meuse and the rocks.
For the general public, along the N95 there are two very impressive free panoramas, the first located to the north of the massif with a view of the castle, the gardens and the head of Mérinos rock, the second located at the South end of the massif next to the CAB hut, where 4 km of the Meuse valley unfold, starting from the meander of Waulsort, centered on that of Freÿr, to end on that of Moniat and overlooking the Al'Lègne rock.
GR 126 (Bruxelles-Semois);
IGN : 53/ 7–8.
The Castle of Freyr is located on the other bank of the Meuse.
Study
The King Baudouin Foundation through the Namur's ancient art Museum supported, in 2013, a major study on the site of Freÿr, both the right bank and the left bank in two volumes, totaling more than 1000 pages. It is called Freÿr sur Meuse, An exceptional heritage in the province of Namur . In particular, there are articles not only on the rocks, but also on the very special fauna and flora that one encounters there.
A nice legend
Freya having lost her husband requested the help of her brother. Freyr gave her a flying wild boar, a purse and a magic sword.
One day, Freya landed at the bottom of the rocks.
The locals having seen the purse tried to steel it, but the magic sword beheaded them. Upon waking up, Freya realized how she had been protected by the sword.
In thanksgiving, she gave the name of her brother to the place.
After WWI, it was not anymore appropriate that the name Freÿr was linked to the Germanic mythology.
Hence it was proposed that Freyr came from the Latin Frigus (cold) .
It does not make sense, since the rocks are irradiated by the son and act as a black body.
References
External links
Freÿr on the Belgian Alpin Club : https://www.clubalpin.be/location/67
Freÿr on the European Climbing sites : https://climb-europe.com/rockclimbingshop/rock-climbing-belgium-and-freyr
Lists of protected heritage sites in Namur (province)
Lists of protected heritage sites in Wallonia | Rocks at Freyr | [
"Physics"
] | 661 | [
"Rocks",
"Physical objects",
"Matter"
] |
73,850,936 | https://en.wikipedia.org/wiki/Hywind%20Tampen | Hywind Tampen is a floating offshore wind farm 140 km off the Norwegian coast in the North Sea owned by the Norwegian state-owned energy company, Equinor. The turbines are mounted on cylindrical concrete spar-buoy foundations.
The wind farm provides electricity for Equinor’s Snorre (platform A and B) and Gullfaks (platforms A, B and C) oil and gas field; Snorre lies just North of the wind farm, and Gullfaks lies just South. Hywind Tampen is the world’s first renewable energy power source for offshore oil and gas, and when commissioned was the world's largest floating offshore wind farm. At full capacity, Hywind Tampen will provide 35% of the electricity demand for Snorre and Gullfaks.
Timeline
Equinor started developing and testing offshore wind installations in 2009, with their first 2.3 MW Hywind Demo project outside of Karmøy, south-west Norway. Equinor also owns the world’s first commercial floating wind park, Hywind Scotland, off the coast of Peterhead, Scotland, commissioned in 2017. After full implementation and operation of the wind farm, Equinor will stand for 47% of global floating wind capacity.
The scheduled power production start was in the 3rd quarter of 2022, but complete installation and operation was not in effect until May 2023. The first power production from Hywind Tampen started in November 2022, and was delivered to Gullfaks A Platform. The windfarm was then connected to the Snorre platforms in May 2023, and officially opened in August 2023. Supply chain issues around steel for the tower sections delayed the final four turbines, meaning they missed the weather window and had to be delayed until spring.
Hywind Tampen has an expected economic lifetime of 19 years, bounded by the respective lifetime of Snorre and Gullfaks operations (Snorre until 2040, Gullfaks A until 2034 and B until 2030, and C until 2032). Hywind Tampen is therefore expected to be abandoned in 2041.
Design
The offshore wind farm consists of 11 Siemens Games SG 8.0-167 DD turbines with a system capacity of 8 MW. Each wind turbine has three 81.5 m blades with 176 m diameter rotors. The turbines are installed on individual floating cylindrical spar buoy concrete structures that are linked together in a shared anchoring system. The anchors are fixed on the ocean floor at a depth of 260–300 meters.
At such water depths, it is not possible to install bottom-fixed solutions, which are the more cost-efficient solution. However, 80% of global offshore wind resources are found in deeper waters (past 60m), and the wind is generally stronger and more consistent. Installation of floating turbines therefore requires a large technical expertise and investments, but the wind farm has greater potential for electricity generation. Equinor intends to expand their offshore wind capacity while reducing cost, and their main strategy for doing so is to invest in technological improvements and large-scale building projects.
The concrete foundations are tall, with the lower being diameter, and the top section reducing in diameter to . They were constructed using a slip forming method by Aker Solutions, who merged with Kværner in 2020. The bottom was constructed in a dry dock in Stord, before being towed to the Vindafjord where the remainder was built and the mechanical outfitting completed.
The turbines are moored to the seabed using anchors and mooring lines and are held afloat both by tension in the mooring system and buoyancy from gravity. The blade movement is regulated through turbine motion controllers, intended to maximize electricity generation, and reduce strain on the tower from corrosion and rough weather.
The turbines are inter-connected in a loop via a string of eleven long dynamic cables, with a cross-section. There are also two export cables that transport the electricity to the Gullfaks-A and Snorre-A Platforms, at and respectively. The cables are rated at 66 kV, and were produced by JDR Cable Systems in Hartlepool, although the cores were manufactured by parent company TFKable in Bydgoszcz, Poland. The cables lack the capacity to export all the electricity produced by Hywind Tampen when running at full capacity.
Hywind Tampen is a largely unmanned wind farm, with an onshore control room in Bergen, on the western coast of Norway.
Contributing parties
Funding
The final investment decision for the project came in October 2019, with contracts worth NOK 3.3 billion. Equinor received NOK 2,329.8 million (approx. $341m USD) in public funding from Enova; a green investment body owned by the Norwegian Ministry of Climate and Environment. Preceding Enova’s investment, the project also received a NOK 566 million investment grant from the Norwegian business sector’s NOx Fund. Further investment was primarily made by the Snorre and Gullfaks partners: Equinor Energy, Petoro AS, OMV (Norge) AS, ExxonMobil Exploration and Production Norway AS, Idemitsu Petroleum Norge AS, DEA Norge AS and Vår Energi AS.
Provisions of parts and installation
Hywind Tampen has awarded a broad series of multinational companies (mostly based in Europe) for the provision of parts and installation of the wind park. DEME Offshore participated in the front-end engineering and design of the windmill structures. Siemens Gamesa was awarded the turbine supply contract and a 5-year maintenance contract for delivering, machine rooms, blades, and towers; seven of which were delivered as planned and in operation in the last quarter of 2022, while the production of the last four lagged behind due to a steel shortage as a result of the war in Ukraine. Their installation was further stalled until the spring of 2023 in anticipation of a manageable weather window. Kværner ASA received the design, construction, and installation contract for the floating substructures. JDR Cable System was awarded the manufacturing contract for the inner array cable network and export cables, with power cores provide by TFKable. Seaway 7 was awarded the contract for their installation. The final array cables were installed by Ocean Installer.
Political support
Support from the Norwegian Government
Based on annual revenues from 2018, Equinor was the world’s seventh largest transnational corporation in the core industries of the ocean economy, which can be attributed to their oil and gas extraction. Although directly benefitting from oil and gas, the Norwegian government has in recent years focused on developing a large-scale growth of green industries, both as a response to climate change and biodiversity loss and to get a first mover advantage within green industries. Their strategy and focal points can be found in the government’s roadmap for green industrial growth. One of its key goals is to make Norway a competitive and leading nation in offshore wind. The oil and gas sector is responsible for approx. ¼ of Norway’s total greenhouse gas emissions (equivalent to 12.2 mill. tons of CO2). The development of the industry and offshore wind technology is therefore the primary initial strategy of the roadmap. Their ambition is to delegate offshore wind areas with the potential of 30 GW production capacity, which is approx. 75% of the current Norwegian energy system capacity. They also highly encourage local supply chain development.
Equinor is a state-owned company, so their practices are obligated to be in line with national strategies and policy. Enova’s financial support should therefore not as come as a surprise. Hywind Tampen is expected to contribute to 200,000 CO2 and 1,000 NOx yearly emission offsets through reductions in first scope emissions from Snorre and Gullfaks. In addition, the project will be used as a testbed to further develop turbines, installation methods, mooring, structures, integration systems etc. This could potentially reduce the cost of future offshore wind projects while creating new industrial opportunities and licences for Norwegian suppliers of offshore wind technologies. Offshore wind is expected to have a 50-fold growth by 2050.
ESA approval
The project has received broad political support, as clearly presented by Enova’s NOK 2.3 billion funding. To approve state funding, the Norwegian Ministry of Trade had to notify the EFTA Surveillance Authority (ESA) to monitor compliance with the European Economic Area. Although Norway is not a member of the EU, they are a member of the EEA and bound by EFTA and ESA rules. The ESA found that Enova funding constituted state aid within art. 61(1) of the EEA Agreement, on the basis that it served to correct market failures.
Support from the EU
The EU Green Deal also lays the foundation for Norway to become a competitive actor in the global offshore wind market. The Norwegian governments expects the Green Deal to lay the foundations for the expansion of Norwegian offshore wind, insofar that EU member states will require a massive increase in their supply of renewable energy to meet their climate targets, and in parallel to increasing an increasing energy security. The EU developed a comprehensive offshore energy implementation strategy in 2021. It sets offshore renewable energy as a top EU priority; aiming to decarbonize electrical generation, hard-to-abate sectors, while simultaneously creating jobs and economic growth, and making the EU a global leader in clean technologies. They aim to create 300 GW of offshore wind installed capacity by 2050, which they suggest would require a massive growth of the industry (about 30x) and an estimated investment of EUR 800 billion. The success of the Norwegian industry can therefore significantly contribute to the EU’s goal. Hywind Tampen involves a wide array of contracts for provisions of parts and installation. Their multinational supply chain, consisting largely of EU member state-based companies, could thereby have a positive effect on the development of offshore wind industries for both parties.
Operational safety considerations
The operation of offshore floating wind farms raises a series of questions related to security and safety. Generally, safety concern factors relating to offshore wind farms are corrosion, fire, lightning strikes, blade failure, personal injury, ship collision and submarine cable damage. The most likely risk relating to the individual safety of Hywind Tampen’s employees comes from are helicopter transportation between the installations and land. Extreme weather conditions could also pose a risk if employees present in, on or around the farm, but the digitalization of operations makes manual labour unnecessary under such circumstances.
Navigation concerns and conflicts
International navigation is in large part protected by the United Nations Convention on the Law of the Seas (UNCLOS), but the traffic around the Hywind Tampen area is in the Norwegian exclusive economic zone and overseen by the Norwegian Coastal administration. Offshore wind farms are known to create navigational conflicts, especially with the shipping industry, fisheries, and navies. Avinor finds no risk of collision with towers for aircraft, nor a need for rerouting. Conflicts mainly arise from an increased risk of collision and economic losses relating to rerouting and loss of fishing areas. The North Sea is an area of high traffic, but Equinor finds in their impact assessment of Hywind Tampen that the likelihood of collision is negligible; largely based on experiences from Snorre and Gullfaks. They find small consequences for the rerouting of navigation, particularly for fishing vessels.
The impact assessment acknowledges potential negative consequences for the commercial fishing and oil and gas industry. Hywind Tampen’s anchoring system prohibits the use of bottom trawling equipment in this area. The system’s chains can resist damage from trawling, but the trawling vessels equipment could suffer damage or loss of equipment. Hywind Tampen is therefore expected to have a certain impact on the trawling practice in the area, but alternative fishing techniques are unlikely to be affected. The anchoring system also limits expansion of the petroleum industry in the area as seismic studies and drilling could destabilize the wind turbines.
Environmental concerns
Hywind Tampen was accepted by Norwegian authorities partly to green the oil and gas sector. The park will have a positive effect on the reduction of greenhouse gasses from Snorre and Gullfaks, primarily CO2 and NOx from natural gas combustion electricity and to run the gas compressors. The reduction of carbon emissions has been a key driver of OFW technologies. However, offshore wind parks are also objects of environmental concern. The production offshore wind turbines require large quantities of raw materials, including rare metals. Their installation also contributes to substantial carbon emissions, and the disruption of marine ecosystems and migratory species movement. Furthermore, the maintenance of the turbines is assessed to emit 40 0000 tons of CO2 over their entire lifespan, and the rerouting of navigation could potentially lead to longer sailing routes which requires more fuel. The decommissioning of wind turbines is perhaps under the most scrutiny. The wind turbines have a life expectancy of 25-years, and their methods of repurposing or disposal is yet to be decided. This hinges on the development of technology, which is currently limited.
Offshore wind parks also attract large scholarly attention regarding their effect on marine life. Interestingly, offshore wind farms can have a positive effect on marine life by acting as an artificial reef concentration nutrients and biodiversity, while also providing shelter from boats, predators, and fishermen. Equinor’s impact assessment finds that the sea floor is uniform and lacks coral structures, and therefore argues that Hywind Tampen’s artificial reef effect can be beneficial for biodiversity. An important contribution to the artificial reef effect is that sufficient light for plant growth only reaches 50m below the water surface in the North Sea, so the Hywind Tampen structures can contribute to the increase of phytoplankton and other key nutrients for marine life.
The North Sea is a rich area of biodiversity and biological production of birds, fish and marine mammals. Equinor was required to present an elaborate assessment on Hywind Tampen’s potential effect on marine life. Their assessment reveals that the most active bird species in the area are Northern Fulmar, Black-Legged Kittiwake, and several species of seagulls and suggest that the wind turbines will have a minimal effect on such seabirds. Hywind Tampen could pose a risk for collision, create interferences, habitat change, and loss, and create a barrier for navigation. The wind farm could affect marine mammals through noise pollution from the wind turbines and anchoring chains, e.g., by interfering with the echolocation of whales. However, Equinor claims that the frequency and range of such noise is unlikely to affect mammals. The North Sea is home to a large diversity of fish species. The most common species in the area around Hywind Tampen are cod, haddock, saithe, and Norwegian pout, and Equinor’s own assessment yet again finds little effect on fish population except for some spawning interferences during implementation.
Security risks
National security considerations
The Norwegian Water Resources and Energy Directorate (NVE) is responsible for coordinating emergency preparedness planning and established the Power Supply Preparedness Organization (KBO) to monitor energy security risks. As a result of an increased global weaponization of energy, particularly emphasized after the attack on the North Stream pipeline, Norway, the EU, and NATO have set an increased focus on the protection, resilience and security surrounding critical infrastructure, and in turn critical marine infrastructure. Whether Hywind Tampen can be considered critical infrastructure is debateable, but it certainly involves in critical processes both directly and indirectly, through connections to submarine cables and pipelines, communication networks and energy provision. Sabotage and disruption could therefore have significant socio-economic effects, especially in terms of financial losses and social trust.
The updated European Union’s Maritime Security Strategy calls for a higher level of cooperation across member states on issues of critical marine infrastructure protection. The EU is also becoming more tightly involved with NATO and the two parties launched a joint military action force to protect critical infrastructure and reinforce common security in January 2023. This task force plays an important and increasing part in the surveillance of Norwegian waters, and NATO presence around platforms and installations in the North Sea is intended to evade attacks on critical infrastructure.
As a result of Russia’s invasion of Ukraine, the EU has rapidly phased out their supply of Russian gas. The importance of renewable energy and the export of Norwegian natural gas has therefore become crucial for the EU and NATO’s energy security, in addition to security and risk management. Norway is now the EU’s largest provider of natural gas, and green industrial growth could make Norway a central supplier of renewable energy. Hywind Tampen’s contribution to the Norwegian oil and gas sector could in fact have a direct positive effect on EU energy security. Norwegian energy access and reliability is extremely high, and 96% of national electricity use (in 2015) is produced in local hydropower plants. Most production of natural gas is therefore exported, and a higher influx of greener supply is beneficial to the EU’s Green strategy. The testbed qualities of Hywind Tampen should therefore seemingly be encouraged by the EU and the Norwegian state.
Sabotage and surveillance
The Norwegian National Security Authority (NSM) asserts that Norway’s national security is less stable than before and will likely become more acute with time. The increasing threat is largely attributed to a broader array of interests and actors, who make use of a wider portfolio of disruptive means for sabotage, espionage, and the mapping of critical infrastructure. On these grounds, the Norwegian Defence as heightened their focus on the resilience and protection of critical marine infrastructure. The Nordic national broadcasting channels have collectively uncovered an increased, prolonged and suspicious activity of Russian ships in the proximity of offshore wind farms and important submarine cable junctures, often ahead of disruptions. The NSM asserts that submarine infrastructure is especially vulnerable to sabotage, and the thousands of kilometres of gas pipeline off the Norwegian coast is impossible to fully monitor. In recent years two submarine cables have been damaged with unknown causes, where in one case 4,2 km of cables disappeared without a trace outside of Vesterålen in 2021. Hywind Tampen may be comforted by their spatial proximity to the largest naval base in the Nordic region, Haakonsvern in Bergen, and a relatively large distance to the Russian boarder.
Cyber security
Cyber attacks could pose a threat to the operations of Hywind Tampen as large parts of operations are controlled from an onshore control room in Bergen. Dependence on computational systems could expose a series of vulnerabilities. Offshore wind farms are generally dependent on digital processing and communication technologies, e.g., long globe-encircling, ICS-specific and hyper local satellite communications and especially the internet. All communication across the Hywind Tampen installations, to the control room and to other vessels will be done through wireless communication. Vulnerabilities in software could therefore lead to accidental or intentional communication interferences between various links. This could for example be tampering with the turbine motion controllers leading to material damage and halts in electricity generation. Hywind Tampen’s breadth of suppliers could also be a potential source of vulnerability in their cyber security. The breadth of external parties involved in the park’s value chain could potentially be a risk factor of leakage of vital information, like vulnerabilities in the cable system or turbines. Most suppliers are however European based companies, which one could assume pursue the same political interests. Suppliers may on the other hand have access to valuable technological insight in Hywind technology which could be in the interest of competitors to get a hold of.
Smuggling
Offshore wind farms, especially unmanned installations, have been an area of interest for anti-smuggling authorities and research. Offshore wind turbines could facilitate smuggling activities by acting as a remote and uncontrolled drop-off point for illegal cargo. Suppliers can simply connect the cargo to the floating structures and leave it there for pick up. International trade routes frequently pass in the vicinity of Hywind Tampen, so smugglers can easily avoid suspicion when being in close range. The wind turbines are intended to mostly be unmanned and therefore serve as a discrete intersection. Hywind Tampen could alternatively serve as a useful base of state and NATO surveillance. Surveillance footage and AIS tracking could uncover illegal actions, such as smuggling, pollution, and unauthorized fishing in protected areas. At the time being, there is no available information on the surveillance capabilities or functions of Hywind Tampen.
References
Floating wind turbines
Renewable energy in Norway
Equinor
Offshore wind farms in the North Sea | Hywind Tampen | [
"Engineering"
] | 4,249 | [
"Floating wind turbines",
"Offshore engineering"
] |
69,389,162 | https://en.wikipedia.org/wiki/Common%20graph | In graph theory, an area of mathematics, common graphs belong to a branch of extremal graph theory concerning inequalities in homomorphism densities. Roughly speaking, is a common graph if it "commonly" appears as a subgraph, in a sense that the total number of copies of in any graph and its complement is a large fraction of all possible copies of on the same vertices. Intuitively, if contains few copies of , then its complement must contain lots of copies of in order to compensate for it.
Common graphs are closely related to other graph notions dealing with homomorphism density inequalities. For example, common graphs are a more general case of Sidorenko graphs.
Definition
A graph is common if the inequality:
holds for any graphon , where is the number of edges of and is the homomorphism density.
The inequality is tight because the lower bound is always reached when is the constant graphon .
Interpretations of definition
For a graph , we have and for the associated graphon , since graphon associated to the complement is . Hence, this formula provides us with the very informal intuition to take a close enough approximation, whatever that means, to , and see as roughly the fraction of labeled copies of graph in "approximate" graph . Then, we can assume the quantity is roughly and interpret the latter as the combined number of copies of in and . Hence, we see that holds. This, in turn, means that common graph commonly appears as subgraph.
In other words, if we think of edges and non-edges as 2-coloring of edges of complete graph on the same vertices, then at least fraction of all possible copies of are monochromatic. Note that in a Erdős–Rényi random graph with each edge drawn with probability , each graph homomorphism from to have probability of being monochromatic. So, common graph is a graph where it attains its minimum number of appearance as a monochromatic subgraph of graph at the graph with
. The above definition using the generalized homomorphism density can be understood in this way.
Examples
As stated above, all Sidorenko graphs are common graphs. Hence, any known Sidorenko graph is an example of a common graph, and, most notably, cycles of even length are common. However, these are limited examples since all Sidorenko graphs are bipartite graphs while there exist non-bipartite common graphs, as demonstrated below.
The triangle graph is one simple example of non-bipartite common graph.
, the graph obtained by removing an edge of the complete graph on 4 vertices , is common.
Non-example: It was believed for a time that all graphs are common. However, it turns out that is not common for . In particular, is not common even though is common.
Proofs
Sidorenko graphs are common
A graph is a Sidorenko graph if it satisfies for all graphons .
In that case, . Furthermore, , which follows from the definition of homomorphism density. Combining this with Jensen's inequality for the function :
Thus, the conditions for common graph is met.
The triangle graph is common
Expand the integral expression for and take into account the symmetry between the variables:
Each term in the expression can be written in terms of homomorphism densities of smaller graphs. By the definition of homomorphism densities:
where denotes the complete bipartite graph on vertex on one part and vertices on the other. It follows:
.
can be related to thanks to the symmetry between the variables and :
where the last step follows from the integral Cauchy–Schwarz inequality. Finally:
.
This proof can be obtained from taking the continuous analog of Theorem 1 in "On Sets Of Acquaintances And Strangers At Any Party"
See also
Sidorenko's conjecture
References
Graph families
Extremal graph theory | Common graph | [
"Mathematics"
] | 774 | [
"Mathematical relations",
"Graph theory",
"Extremal graph theory"
] |
69,389,829 | https://en.wikipedia.org/wiki/Age-1 | The age-1 gene is located on chromosome 2 in C.elegans. It gained attention in 1983 for its ability to induce long-lived C. elegans mutants. The age-1 mutant, first identified by Michael Klass, was reported to extend mean lifespan by over 50% at 25 °C when compared to the wild type worm (N2) in 1987 by Johnson et al. Development, metabolism, lifespan, among other processes have been associated with age-1 expression. The age-1 gene is known to share a genetic pathway with daf-2 gene that regulates lifespan in worms. Additionally, both age-1 and daf-2 mutants are dependent on daf-16 and daf-18 genes to promote lifespan extension.
Long-lived age-1 mutants are resistant to oxidative stress and UV light. Age-1 mutants also have a higher DNA repair capability than wild-type C. elegans. Knockdown of the nucleotide excision repair gene Xpa-1 increases sensitivity to UV and reduces the life span of the long-lived mutants. These findings support the hypothesis that DNA repair capability underlies longevity.
Insulin/IGF-1 signaling (IIS) pathway
The age-1 gene is said to encode for AGE-1, the catalytic subunit ortholog to phosphoinositide 3-kinase in C.elegans, which plays an important role in the insulin/IGF-1(IIS) signaling pathway. This pathway gets activated upon binding of an insulin-like peptide to the DAF-2/IGF1R receptor. Binding causes dimerization and phosphorylation of the receptor, which induces recruitment of the DAF-2 receptor substrate IST-1. Subsequently, IST-1 promotes activation of both AGE-1/PI3K and its adaptor subunit AAP-1. AGE-1 then induces conversion of phosphatidylinositol- 4,5-biphosphate (PIP2) to phosphatidylinositol-3,4,5-triphosphate (PIP3). This conversion can be reversed by DAF-18 (PTEN in humans). PIP3, causes activation of its major effector PDK-1, which in turn promotes phosphorylation of AKT 1/2, and SGK-1. This phosphorylation causes inhibition of the transcription factor DAF-16/FoXO and glucocorticoid-inducible kinase-1(SKN-1), preventing the expression of downstream genes involved in longevity. In other words, activation of the IIS pathway blocks expression of genes known to extend lifespan by preventing DAF-16 from translocating to the nucleus and activating them.
History
The age-1 gene was first characterized by Thomas Johnson as a follow up study to Michael Klass's findings on the isolation of long-lived C. elegans mutants. Johnson demonstrated that long-lived age-1 (hx546) mutants did not have significant differences in growth rate or development. Additionally, all age-1 isolates were also fer-15 (mutants sensitive to temperature), suggesting that both genes were inherited together. This result suggested that the age phenotype was caused by a single mutation. Johnson proposed a negative pleiotropy theory, in which the age-1 gene is beneficial early in life but harmful at a later stage, on the basis that the long-lived mutants had decreased self-fertility compared to controls. This theory was contradicted in 1993 by Johnson himself when he ablated the fertility defect on the mutant, and the animals still lived long. After the age-1 gene was discovered, Cynthia Kenyon published groundbreaking research on doubling the lifespan of C. elegans by the insulin/IGF-1 pathway. The age-1 gene plays a pivotal role in the IGF-1 pathway and encodes the homolog of phosphatidylinositol-3-OH kinase (PI3K) catalytic subunits in mammals.
See also
Unfolded protein response
Genetics of aging
References
Aging-related genes
Caenorhabditis elegans genes | Age-1 | [
"Biology"
] | 875 | [
"Senescence",
"Aging-related genes"
] |
69,390,258 | https://en.wikipedia.org/wiki/Thia-crown%20ether | In organic chemistry, thia-crown ethers are organosulfur compounds which are the thia analogues of crown ethers (cyclic polyethers). That is, they have a sulfur atom (sulfide linkage, ) in place of each oxygen atom (ether linkage, ) around the ring. While the parent crown ethers have the formulae , the parent thia-crown ethers have the formulae , where n = 3, 4, 5, 6. They have trivial names "x-ane-Sy", where x and y are the number of atoms in the ring and the number of those atoms that are sulfur, respectively. Thia-crown ethers exhibit affinities for transition metals.
1,4,7-Trithiacyclononane (9-ane-S3) is a tridentate ligand and forms complexes with many metal ions, including those considered hard, such as copper(II) and iron(II).
Tetradentate 14-ane-S4 and the hexadentate 18-ane-S6 are also known. Evaluation of antibacterial activities of some thia crown ethers indicated that they can be considered as inhibitors for S. aureus methicillin resistance and P. aeruginosa. In addition, some of these compounds were screened for their antibacterial and antifungal activity on Klebsiella pneumoniae, Staphilococcus aureus, Pseudomanas aeruginosa and Candida albicans .
References
Sulfur heterocycles
Thioethers
Chelating agents
Macrocycles | Thia-crown ether | [
"Chemistry"
] | 341 | [
"Organic compounds",
"Chelating agents",
"Macrocycles",
"Process chemicals"
] |
69,390,480 | https://en.wikipedia.org/wiki/Samsung%20Galaxy%20A03 | The Samsung Galaxy A03 is a series of budget Android smartphones manufactured by Samsung Electronics that includes the A03, A03s and A03 Core. They have a 6.5-inch FHD+ Infinity-V display, a 5000 mAh Li-Po battery, and ship with Android 11 (can be upgraded to Android 13).
The A03 has a dual-camera setup with a 48 MP main camera.
Specifications
Hardware
The Samsung Galaxy A03 is equipped with a 6.5-inch PLS TFT capacitive touchscreen with a resolution of 1600×720 pixels. The phone itself measures 164.2 mm × 75.9 mm × 9.1 mm (6.46 x 2.99 x 0.36 inches) and weighs 196 grams (6.91 oz). The A03 is constructed with a glass front and a plastic back and frame.
Camera
The Samsung Galaxy A03 has a dual-camera setup arranged vertically on the left side of the rear of the phone along with the flash. The main camera is a 48 MP wide lens and the second is a 2 MP depth sensor. The main camera can record video up at 1080p @ 30 fps. A single 5 MP front-facing camera is present in a notch.The Samsung Galaxy A03 Core does have the same as a regular A03, but it only has one camera that is 8 MP on the back and 5 MP on the front.
Processor
The Unisoc T606 is an SoC designed by Chinese semiconductor company Unisoc, featuring an octa-core CPU (2x Cortex-A75 cores clocked at 2 GHz and 6x Cortex-A55 cores clocked at 1.6 GHz) and a Mali-G57 MP1 GPU.
Memory
The Samsung Galaxy A03s has varying storage configurations from 32 GB to 128 GB of internal storage and 3 GB to 4 GB of RAM. Both storage and RAM play an important role in the device's performance and usability. eMMC 5.1 technology is used for its internal storage, providing faster read and write speeds than previous versions. Additionally, the device includes a microSDXC slot, allowing users to expand their storage capacity up to 1 TB.
Battery
The Galaxy A03 has a Li-Po 5000 mAh non-removable battery. With a power-efficient processor and optimized software, the Galaxy A03 can provide up to 15 hours of internet browsing, up to 34 hours of talk time, and up to 19 hours of video playback on a single charge.
Software
The Samsung Galaxy A03 originally came with One UI Core 3.1 over Android 11 but it can be updated to One UI Core 5.1 over Android 13.
References
Samsung Galaxy
Mobile phones introduced in 2021
Android (operating system) devices
Samsung smartphones
Mobile phones with multiple rear cameras
Discontinued Samsung Galaxy smartphones | Samsung Galaxy A03 | [
"Technology"
] | 600 | [
"Crossover devices",
"Phablets"
] |
69,391,314 | https://en.wikipedia.org/wiki/Architecture%20of%20Israel%20%28magazine%29 | Architecture of Israel (AI) is a Hebrew & English bilingual quarterly magazine dealing with architecture, interior design and the environment.
Published since January 1988, the aims of the magazine, as stated on its website www.aiq.co.il, are to "promote climate and environmental awareness, creative and feasible architecture". AI provides a stage for Israeli architecture in an international context and conducts each year an international competition together with the European Union, titled "Project of the Year". The judges are worldwide known academics and architects.
Permanent sections:
"Food for Thought", deals with how other fields of life impact architecture
"Curiosity", covering events, competitions and exhibitions
Interviews with Israeli and international architects
"House of the Season", presents a different perspective on the residential issue
"Guest of the Season", the professional profile of a selected architect
"Architects Telling", behind-the-scenes stories about well-known buildings
References
Architecture
Architecture
Architecture magazines
Magazines established in 1988
Magazines published in Israel
1988 establishments in Israel
Design magazines
Hebrew-language magazines
English-language magazines
Bilingual magazines | Architecture of Israel (magazine) | [
"Engineering"
] | 215 | [
"Design magazines",
"Design"
] |
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