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πŸ”— Vancouver Special

πŸ”— Canada πŸ”— Architecture πŸ”— Canada/British Columbia πŸ”— Canada/Vancouver

The Vancouver Special is an architectural style of residential houses developed in Metro Vancouver, Canada. The style was popular in the 1960s to 1980s due to ability to maximize floor space with relatively cheap construction costs.

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πŸ”— Pando (tree)

πŸ”— United States πŸ”— Plants πŸ”— United States/Utah

Pando (Latin for "I spread out"), also known as the trembling giant, is a clonal colony of an individual male quaking aspen (Populus tremuloides) determined to be a single living organism by identical genetic markers and assumed to have one massive underground root system. The plant is located in the Fremont River Ranger District of the Fishlake National Forest at the western edge of the Colorado Plateau in south-central Utah, United States, around 1 mile (1.6Β km) southwest of Fish Lake. Pando occupies 43 hectares (106 acres) and is estimated to weigh collectively 6,000,000 kilograms (6,600 short tons), making it the heaviest known organism. The root system of Pando, at an estimated 80,000 years old, is among the oldest known living organisms.

Pando is currently thought to be dying. Though the exact reasons are not known, it is thought to be a combination of factors including drought, grazing, human development, and fire suppression. The Western Aspen Alliance, a research group at Utah State University’s S.J. & Jessie E. Quinney College of Natural Resources, has been studying the tree in an effort to save it, and the United States Forest Service is currently experimenting with several 5-acre (2Β ha) sections of it in an effort to find a means to save it. Grazing animals have threatened Pando's ability to produce young offsprings to replace trees that are dying. Human development in the area is another threat, these two threats have caused pando trees to shrink in size and decrease over the past 50 years.

A study published in October 2018 concludes that Pando has not been growing for the past 30–40 years. Human interference was named as the primary cause, with the study specifically citing people allowing cattle and deer populations to thrive, their grazing resulting in fewer saplings and dying individual trees.

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πŸ”— TIL: The Data Furnace

πŸ”— Computing πŸ”— Energy πŸ”— Microsoft

The data furnace is a method of heating residential homes or offices by running computers in them, which release considerable amounts of waste heat. Data furnaces can theoretically be cheaper than storing computers in huge data centers because the higher cost of electricity in residential areas (when compared to industrial zones) can be offset by charging the home owner for the heat that the data center gives off. Some large companies that store and process thousands of gigabytes of data believe that data furnaces could be cheaper because there would be little to no overhead costs. The cost of a traditional data storage center is up to around $400 per server, whereas the overhead cost per server of a home data furnace is around $10. Individuals had already begun using computers as a heat source by 2011.

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πŸ”— Hybridogenesis in water frogs

πŸ”— Genetics πŸ”— Amphibians and Reptiles

The fertile hybrids of European water frogs (genus Pelophylax) reproduce by hybridogenesis (hemiclonally). This means that during gametogenesis, they discard the genome of one of the parental species and produce gametes of the other parental species (containing a genome not recombined with the genome of the first parental species). The first parental genome is restored by fertilization of these gametes with gametes from the first species (sexual host). In all-hybrid populations of the edible frog Pelophylax kl. esculentus, however, triploid hybrids provide this missing genome.

Because half of the genome is transmitted to the next generation clonally (not excluded unrecombined intact genome), and only the other half sexually (recombined genome of the sexual host), the hybridogenesis is a hemiclonal mode of reproduction.

For example, the edible frog Pelophylax kl. esculentus (mostly RL genome), which is a hybridogenetic hybrid of the marsh frog P. ridibundus (RR) and the pool frog P. lessonae (LL), usually excludes the lessonae genome (L) and generates gametes of the P. ridibundus (R). In other words, edible frogs produce gametes of marsh frogs.

The hybrid populations are propagated, however, not by the above primary hybridisations, but predominantly by backcrosses with one of the parental species they coexist (live in sympatry) with (see below in the middle).

Since the hybridogenetic hybrids require another taxon as sexual host to reproduce, usually one of the parental species, they are called kleptons (with "kl." in scientific names).

There are three known hybridogenetic hybrids of the European water frogs:

  • edible frog Pelophylax kl. esculentus (usually genotype RL):
    pool frog P. lessonae (LL) Γ— P. ridibundus (RR)
  • Graf's hybrid frog Pelophylax kl. grafi (PR):
    Perez's frog P. perezi (PP) Γ— P. ridibundus (RR) or
    Perez's frog P. perezi (PP) Γ— edible frog P. kl. esculentus (RE)
    (it is unclear which one crossing was the primary hybridisation)
  • Italian edible frog Pelophylax kl. hispanicus (RB):
    Italian pool frog P. bergeri (BB) Γ— P. ridibundus (RR)

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πŸ”— Heathkit

πŸ”— Amateur radio πŸ”— Michigan

Heathkit is the brand name of kits and other electronic products produced and marketed by the Heath Company. The products over the decades have included electronic test equipment, high fidelity home audio equipment, television receivers, amateur radio equipment, robots, electronic ignition conversion modules for early model cars with point style ignitions, and the influential Heath H-8, H-89, and H-11 hobbyist computers, which were sold in kit form for assembly by the purchaser.

Heathkit manufactured electronic kits from 1947 until 1992. After closing that business, the Heath Company continued with its products for education, and motion-sensor lighting controls. The lighting control business was sold around 2000. The company announced in 2011 that they were reentering the kit business after a 20-year hiatus but then filed for bankruptcy in 2012, and under new ownership began restructuring in 2013. As of 2019, the company has a live website with newly-designed products, services, vintage kits, and replacement parts for sale.

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πŸ”— Lambda Cube

πŸ”— Computing πŸ”— Mathematics

In mathematical logic and type theory, the Ξ»-cube is a framework introduced by Henk Barendregt to investigate the different dimensions in which the calculus of constructions is a generalization of the simply typed Ξ»-calculus. Each dimension of the cube corresponds to a new kind of dependency between terms and types. Here, "dependency" refers to the capacity of a term or type to bind a term or type. The respective dimensions of the Ξ»-cube correspond to:

  • y-axis ( ↑ {\displaystyle \uparrow } ): terms that can bind types, corresponding to polymorphism.
  • x-axis ( β†’ {\displaystyle \rightarrow } ): types that can bind terms, corresponding to dependent types.
  • z-axis ( β†— {\displaystyle \nearrow } ): types that can bind types, corresponding to (binding) type operators.

The different ways to combine these three dimension yield the 8 vertices of the cube, each corresponding to a different kind of typed system. The Ξ»-cube can be generalized into the concept of a pure type system.

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πŸ”— Comparison of Afrikaans and Dutch

πŸ”— Languages πŸ”— South Africa

Afrikaans is a daughter language of Dutch andβ€”unlike Netherlands Dutch, Belgian Dutch and Surinamese Dutchβ€”a separate standard language rather than a national variety. As an estimated 90 to 95% of Afrikaans vocabulary is ultimately of Dutch origin, there are few lexical differences between the two languages; however, Afrikaans has a considerably more regular morphology, grammar, and spelling.

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πŸ”— Elixir Sulfanilamide

πŸ”— United States πŸ”— Medicine

Elixir sulfanilamide was an improperly prepared sulfonamide antibiotic that caused mass poisoning in the United States in 1937. It is believed to have killed more than 100 people. The public outcry caused by this incident and other similar disasters led to the passing of the 1938 Federal Food, Drug, and Cosmetic Act, which significantly increased the Food and Drug Administration's powers to regulate drugs.

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πŸ”— X32 ABI

πŸ”— Computing πŸ”— Computing/Software πŸ”— Linux

The x32 ABI is an application binary interface (ABI) and one of the interfaces of the Linux kernel. It allows programs to take advantage of the benefits of x86-64 instruction set (larger number of CPU registers, better floating-point performance, faster position-independent code, shared libraries, function parameters passed via registers, faster syscall instruction) while using 32-bit pointers and thus avoiding the overhead of 64-bit pointers.

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πŸ”— Hyperloop

πŸ”— Technology πŸ”— Physics πŸ”— Transport πŸ”— Trains πŸ”— Engineering

A Hyperloop is a proposed mode of passenger and freight transportation, first used to describe an open-source vactrain design released by a joint team from Tesla and SpaceX. Hyperloop is a sealed tube or system of tubes through which a pod may travel free of air resistance or friction conveying people or objects at high speed while being very efficient, thereby drastically reducing travel times over medium-range distances.

Elon Musk's version of the concept, first publicly mentioned in 2012, incorporates reduced-pressure tubes in which pressurized capsules ride on air bearings driven by linear induction motors and axial compressors.

The Hyperloop Alpha concept was first published in August 2013, proposing and examining a route running from the Los Angeles region to the San Francisco Bay Area, roughly following the Interstate 5 corridor. The Hyperloop Genesis paper conceived of a hyperloop system that would propel passengers along the 350-mile (560Β km) route at a speed of 760Β mph (1,200Β km/h), allowing for a travel time of 35 minutes, which is considerably faster than current rail or air travel times. Preliminary cost estimates for this LA–SF suggested route were included in the white paperβ€”US$6 billion for a passenger-only version, and US$7.5 billion for a somewhat larger-diameter version transporting passengers and vehiclesβ€”although transportation analysts had doubts that the system could be constructed on that budget; some analysts claimed that the Hyperloop would be several billion dollars overbudget, taking into consideration construction, development, and operation costs.

The Hyperloop concept has been explicitly "open-sourced" by Musk and SpaceX, and others have been encouraged to take the ideas and further develop them. To that end, a few companies have been formed, and several interdisciplinary student-led teams are working to advance the technology. SpaceX built an approximately 1-mile-long (1.6Β km) subscale track for its pod design competition at its headquarters in Hawthorne, California.

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