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π Mammals are shaped by descent from nocturnal animals
The nocturnal bottleneck hypothesis is a hypothesis to explain several mammalian traits. In 1942, Gordon Lynn Walls described this concept which states that placental mammals were mainly or even exclusively nocturnal through most of their evolutionary story, starting with their origin 225 million years ago, and only ending with the demise of the non-avian dinosaurs 66 million years ago. While some mammal groups have later evolved to fill diurnal niches, the approximately 160 million years spent as nocturnal animals has left a lasting legacy on basal anatomy and physiology, and most mammals are still nocturnal.
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- "Mammals are shaped by descent from nocturnal animals" | 2022-08-17 | 203 Upvotes 76 Comments
π Pantala Flavescens
Pantala flavescens, the globe skimmer, globe wanderer or wandering glider, is a wide-ranging dragonfly of the family Libellulidae. This species and Pantala hymenaea, the "spot-winged glider", are the only members of the genus Pantala. It was first described by Johan Christian Fabricius in 1798. It is considered to be the most widespread dragonfly on the planet with good population on every continent except Antarctica although rare in Europe. Globe skimmers make an annual multigenerational journey of some 18,000Β km (about 11,200 miles); to complete the migration, individual globe skimmers fly more than 6,000Β km (3,730 miles)βone of the farthest known migrations of all insect species.
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- "Pantala Flavescens" | 2022-08-16 | 18 Upvotes 9 Comments
π Floppy Disk Variants
The floppy disk is a data storage and transfer medium that was ubiquitous from the mid-1970s well into the 2000s. Besides the 3Β½-inch and 5ΒΌ-inch formats used in IBM PC compatible systems, or the 8-inch format that preceded them, many proprietary floppy disk formats were developed, either using a different disk design or special layout and encoding methods for the data held on the disk.
π An Instinct for Dragons
An Instinct for Dragons is a book by University of Central Florida anthropologist, David E. Jones, in which he seeks to explain the universality of dragon images in the folklore of human societies. In the introduction, Jones conducts a survey of dragon myths from cultures around the world and argues that certain aspects of dragons or dragon-like mythical creatures are found very widely. He claims that even the Inuit have a reptilian dragon-like monster, even though (living in a frigid environment unsuited for cold-blooded animals) they had never seen an actual reptile.
Jones then argues against the common hypothesis that dragon myths might be motivated by primitive discoveries of dinosaur fossils (he argues that there are widespread traits of dragons in folklore which are not observable from fossils), and claims that the common traits of dragons seem to be an amalgam of the principal predators of our ancestral hominids, which he names as the raptors, great cats (especially leopards) and pythons.
The hypothesis to which Jones conforms is that over millions of years of evolution, members of a species will evolve an instinctive fear of their predators, and he proposes ways in which these fearful images may be merged in artistic or cultural expression to create the dragon image and, perhaps, other kinds of hybrid monster.
Finally he suggests sociological reasons for why such images may be perceived differently at different stages of a culture to try to explain why Chinese dragons are considered basically good and representative of government, but the great majority (although not all) European dragons are evil and often represent chaos.
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- "An Instinct for Dragons" | 2022-08-14 | 40 Upvotes 32 Comments
π BRL-CAD
BRL-CAD is a constructive solid geometry (CSG) solid modeling computer-aided design (CAD) system. It includes an interactive geometry editor, ray tracing support for graphics rendering and geometric analysis, computer network distributed framebuffer support, scripting, image-processing and signal-processing tools. The entire package is distributed in source code and binary form.
Although BRL-CAD can be used for a variety of engineering and graphics applications, the package's primary purpose continues to be the support of ballistic and electromagnetic analyses. In keeping with the Unix philosophy of developing independent tools to perform single, specific tasks and then linking the tools together in a package, BRL-CAD is basically a collection of libraries, tools, and utilities that work together to create, raytrace, and interrogate geometry and manipulate files and data. In contrast to many other 3D modelling applications, BRL-CAD primarily uses CSG rather than boundary representation. This means BRL-CAD can "study physical phenomena such as ballistic penetration and thermal, radiative, neutron, and other types of transport". It does also support boundary representation.
The BRL-CAD libraries are designed primarily for the geometric modeler who also wants to tinker with software and design custom tools. Each library is designed for a specific purpose: creating, editing, and ray tracing geometry, and image handling. The application side of BRL-CAD also offers a number of tools and utilities that are primarily concerned with geometric conversion, interrogation, image format conversion, and command-line-oriented image manipulation.
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- "BRL-CAD" | 2022-08-13 | 74 Upvotes 82 Comments
π Preparedness Paradox
The preparedness paradox is the proposition that if a society or individual acts effectively to mitigate a potential disaster such as a pandemic, natural disaster or other catastrophe so that it causes less harm, the avoided danger will be perceived as having been much less serious because of the limited damage actually caused. The paradox is the incorrect perception that there had been no need for careful preparation as there was little harm, although in reality the limitation of the harm was due to preparation. Several cognitive biases can consequently hamper proper preparation for future risks.
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- "Preparedness Paradox" | 2022-08-15 | 236 Upvotes 124 Comments
π Gravity Probe B
Gravity Probe B (GP-B) was a satellite-based experiment to test two unverified predictions of general relativity: the geodetic effect and frame-dragging. This was to be accomplished by measuring, very precisely, tiny changes in the direction of spin of four gyroscopes contained in an Earth-orbiting satellite at 650Β km (400Β mi) altitude, crossing directly over the poles.
The satellite was launched on 20 April 2004 on a Delta II rocket. The spaceflight phase lasted until ; Its aim was to measure spacetime curvature near Earth, and thereby the stressβenergy tensor (which is related to the distribution and the motion of matter in space) in and near Earth. This provided a test of general relativity, gravitomagnetism and related models. The principal investigator was Francis Everitt.
Initial results confirmed the expected geodetic effect to an accuracy of about 1%. The expected frame-dragging effect was similar in magnitude to the current noise level (the noise being dominated by initially unmodeled effects due to nonuniform coatings on the gyroscopes). Work continued to model and account for these sources of error, thus permitting extraction of the frame-dragging signal. By , the frame-dragging effect had been confirmed to within 15% of the expected result, and the NASA report indicated that the geodetic effect was confirmed to be better than 0.5%.
In an article published in the journal Physical Review Letters in , the authors reported analysis of the data from all four gyroscopes results in a geodetic drift rate of β6601.8Β±18.3Β mas/yr and a frame-dragging drift rate of β37.2Β±7.2Β mas/yr, in good agreement with the general relativity predictions of β6606.1Β±0.28%Β mas/yr and β39.2Β±0.19%Β mas/yr, respectively.
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- "Gravity Probe B" | 2022-08-14 | 70 Upvotes 15 Comments
π Mozart Effect
The Mozart effect is the theory that listening to the music of Mozart may temporarily boost scores on one portion of an IQ test. Popular science versions of the theory make the claim that "listening to Mozart makes you smarter" or that early childhood exposure to classical music has a beneficial effect on mental development.
The original study from 1993 reported a short-term (lasting about 15 minutes) improvement on the performance of certain kinds of mental tasks known as spatial reasoning, such as folding paper and solving mazes. The results were highly exaggerated by the popular press and became "Mozart makes you smart", which was said to apply to children in particular (the original study included 36 college students). These claims led to a commercial fad with Mozart CDs being sold to parents, the U.S. state of Georgia even proposed a budget to provide every child with a CD of classical music.
A meta-analysis of studies that have replicated the original study shows that there is little evidence that listening to Mozart has any particular effect on spatial reasoning. The author of the original study has stressed that listening to Mozart has no effect on general intelligence.
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- "Mozart Effect" | 2022-08-10 | 84 Upvotes 76 Comments
π Spaghetti-Tree Hoax
The spaghetti-tree hoax was a three-minute hoax report broadcast on April Fools' Day 1957 by the BBC current-affairs programme Panorama, purportedly showing a family in southern Switzerland harvesting spaghetti from the family "spaghetti tree". At the time spaghetti was relatively unknown in the UK, so many British people were unaware that it is made from wheat flour and water; a number of viewers afterwards contacted the BBC for advice on growing their own spaghetti trees. Decades later, CNN called this broadcast "the biggest hoax that any reputable news establishment ever pulled".
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- "Spaghetti-Tree Hoax" | 2023-01-29 | 174 Upvotes 93 Comments
π 2022 Oder Environmental Disaster
The 2022 Oder environmental disaster is a mass die-off of fish, beavers and other wildlife in the Oder river in Poland and Germany, causing a health and environmental crisis in large parts of the country and subsequently a political scandal.
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- "2022 Oder Environmental Disaster" | 2022-08-13 | 215 Upvotes 43 Comments