Have a deep view into what people are curious about.

🔗 Germany 🔗 Bridges and Tunnels

The Magdeburg Water Bridge (German: Kanalbrücke Magdeburg) is a large navigable aqueduct in central Germany, located near Magdeburg. The largest canal underbridge in Europe, it spans the river Elbe and directly connects the Mittellandkanal to the west and Elbe-Havel Canal to the east of the river, allowing large commercial ships to pass between the Rhineland and Berlin without having to descend into and then climb out of the Elbe itself.

🔗 Food and drink 🔗 Birds

A chicken can be hypnotized, or put into a trance, by holding its head down against the ground, and drawing a line along the ground with a stick or a finger, starting at the beak and extending straight outward in front of the chicken. If the chicken is hypnotized in this manner, it will continue to stare at the line, remaining immobile for as long as 30 minutes. Other methods of inducing this state are also known. Ethologists refer to this state as 'tonic immobility' i.e. a natural state of semi-paralysis that some animals enter when presented with a threat, which is probably a defensive mechanism intended to feign death, albeit rather poorly.

The first known written reference for this method came in 1646, in Mirabele Experimentum de Imaginatione Gallinae by Athanasius Kircher in Rome.

The Stigler diet is an optimization problem named for George Stigler, a 1982 Nobel Laureate in economics, who posed the following problem:

For a moderately active man weighing 154 pounds, how much of each of 77 foods should be eaten on a daily basis so that the man’s intake of nine nutrients will be at least equal to the recommended dietary allowances (RDAs) suggested by the National Research Council in 1943, with the cost of the diet being minimal?

The nutrient RDAs required to be met in Stigler’s experiment were calories, protein, calcium, iron, as well as vitamins A, B₁, B₂, B₃, and C. The result was an annual budget allocated to foods such as evaporated milk, cabbage, dried navy beans, and beef liver at a cost of approximately $0.11 a day in 1939 U.S. dollars.

While the name “Stigler Diet” was applied after the experiment by outsiders, according to Stigler, “No one recommends these diets for anyone, let alone everyone.” The Stigler diet has been much ridiculed for its lack of variety and palatability; however, his methodology has received praise and is considered to be some of the earliest work in linear programming.

🔗 Medicine 🔗 Sociology 🔗 Physiology 🔗 Medicine/Cardiology 🔗 Medicine/Society and Medicine

The Roseto effect is the phenomenon by which a close-knit community experiences a reduced rate of heart disease. The effect is named for Roseto, Pennsylvania. The Roseto effect was first noticed in 1961 when the local Roseto doctor encountered Dr. Stewart Wolf, then head of Medicine of the University of Oklahoma, and they discussed, over a couple of beers, the unusually low rate of myocardial infarction in the Italian American community of Roseto compared with other locations. Many studies followed, including a 50-year study comparing Roseto to nearby Bangor. As the original authors had predicted, as the Roseto cohort shed their Italian social structure and became more Americanized in the years following the initial study, heart disease rates increased, becoming similar to those of neighboring towns.

From 1954 to 1961, Roseto had nearly no heart attacks for the otherwise high-risk group of men 55 to 64, and men over 65 had a death rate of 1% while the national average was 2%. Widowers outnumbered widows, as well.

These statistics were at odds with a number of other factors observed in the community. They smoked unfiltered stogies, drank wine "with seeming abandon" in lieu of milk and soft drinks, skipped the Mediterranean diet in favor of meatballs and sausages fried in lard with hard and soft cheeses. The men worked in the slate quarries where they contracted illnesses from gases and dust. Roseto also had no crime, and very few applications for public assistance.

Wolf attributed Rosetans' lower heart disease rate to lower stress. "'The community,' Wolf says, 'was very cohesive. There was no keeping up with the Joneses. Houses were very close together, and everyone lived more or less alike.'" Elders were revered and incorporated into community life. Housewives were respected, and fathers ran the families.

🔗 Germany

The Nazi book burnings were a campaign conducted by the German Student Union (the "DSt") to ceremonially burn books in Nazi Germany and Austria in the 1930s. The books targeted for burning were those viewed as being subversive or as representing ideologies opposed to Nazism. These included books written by Jewish, pacifist, religious, liberal, anarchist, socialist, communist, and sexologist authors among others. The first books burned were those of Karl Marx and Karl Kautsky.

"Pierre Menard, Author of the Quixote" (original Spanish title: "Pierre Menard, autor del Quijote") is a short story by Argentine writer Jorge Luis Borges.

It originally appeared in Spanish in the Argentine journal Sur in May 1939. The Spanish-language original was first published in book form in Borges's 1941 collection El jardín de senderos que se bifurcan (The Garden of Forking Paths), which was included in his much-reprinted Ficciones (1944).

In machine learning, the kernel embedding of distributions (also called the kernel mean or mean map) comprises a class of nonparametric methods in which a probability distribution is represented as an element of a reproducing kernel Hilbert space (RKHS). A generalization of the individual data-point feature mapping done in classical kernel methods, the embedding of distributions into infinite-dimensional feature spaces can preserve all of the statistical features of arbitrary distributions, while allowing one to compare and manipulate distributions using Hilbert space operations such as inner products, distances, projections, linear transformations, and spectral analysis. This learning framework is very general and can be applied to distributions over any space ${\displaystyle \Omega }$ on which a sensible kernel function (measuring similarity between elements of ${\displaystyle \Omega }$) may be defined. For example, various kernels have been proposed for learning from data which are: vectors in ${\displaystyle \mathbb {R} ^{d}}$, discrete classes/categories, strings, graphs/networks, images, time series, manifolds, dynamical systems, and other structured objects. The theory behind kernel embeddings of distributions has been primarily developed by Alex Smola, Le Song , Arthur Gretton, and Bernhard Schölkopf. A review of recent works on kernel embedding of distributions can be found in.

The analysis of distributions is fundamental in machine learning and statistics, and many algorithms in these fields rely on information theoretic approaches such as entropy, mutual information, or Kullback–Leibler divergence. However, to estimate these quantities, one must first either perform density estimation, or employ sophisticated space-partitioning/bias-correction strategies which are typically infeasible for high-dimensional data. Commonly, methods for modeling complex distributions rely on parametric assumptions that may be unfounded or computationally challenging (e.g. Gaussian mixture models), while nonparametric methods like kernel density estimation (Note: the smoothing kernels in this context have a different interpretation than the kernels discussed here) or characteristic function representation (via the Fourier transform of the distribution) break down in high-dimensional settings.

Methods based on the kernel embedding of distributions sidestep these problems and also possess the following advantages:

1. Data may be modeled without restrictive assumptions about the form of the distributions and relationships between variables
2. Intermediate density estimation is not needed
3. Practitioners may specify the properties of a distribution most relevant for their problem (incorporating prior knowledge via choice of the kernel)
4. If a characteristic kernel is used, then the embedding can uniquely preserve all information about a distribution, while thanks to the kernel trick, computations on the potentially infinite-dimensional RKHS can be implemented in practice as simple Gram matrix operations
5. Dimensionality-independent rates of convergence for the empirical kernel mean (estimated using samples from the distribution) to the kernel embedding of the true underlying distribution can be proven.
6. Learning algorithms based on this framework exhibit good generalization ability and finite sample convergence, while often being simpler and more effective than information theoretic methods

Thus, learning via the kernel embedding of distributions offers a principled drop-in replacement for information theoretic approaches and is a framework which not only subsumes many popular methods in machine learning and statistics as special cases, but also can lead to entirely new learning algorithms.

🔗 Psychology

Bedtime procrastination or revenge bedtime procrastination is a psychological phenomenon in which people stay up later than they desire in an attempt to have control over the night because they perceive themselves (perhaps subconsciously) to lack influence over events during the day.

🔗 Architecture 🔗 Classical Greece and Rome

The Roman architectural revolution, also known as the concrete revolution, is the name sometimes given to the widespread use in Roman architecture of the previously little-used architectural forms of the arch, vault, and dome. For the first time in history, their potential was fully exploited in the construction of a wide range of civil engineering structures, public buildings, and military facilities. These included amphitheatres, aqueducts, baths, bridges, circuses, dams, roads, and temples.

A crucial factor in this development that saw a trend to monumental architecture was the invention of Roman concrete (also called opus caementicium), which led to the liberation of the shape from the dictate of the traditional materials of stone and brick.

For the first time in recorded history we find evidence of an interest in the shapes of the space contained strong enough to outweigh the functional logic of the masonry masses that contained it. There was nothing new in the employment of curvilinear or polygonal forms, as such...But in so far as such buildings incorporated curvilinear or polygonal rooms and corridors, the shapes of these were determined by the form of the building as a whole, not by any aesthetic principle.

The development of Roman architecture, however, did not remain limited to these new forms and materials. An unrelated process of architectural innovation continued unabated, which, although less conspicuous, proved their usefulness for solving structural problems and found their way permanently into Western architecture, such as the lintel arch, the independent corbel, and the metal-tie.

During the Age of Augustus, almost the entire city of Rome was rebuilt causing an influx of craftsman and architects from all across Europe. Emperor Augustus aimed to develop new ideas in the construction of his buildings that would forever defy the limits that were ever thought possible. The Mausoleum in Campus Martius was one of the major monuments built by Augustus during his reign that was made almost entirely of concrete using updated construction techniques. The concrete is used in concentric rings that support the structure of the building like walls. The Theatre of Marcellus was another concrete triumph completed during the Age of Augustus, dedicated to the nephew of the emperor. The brick-faced concrete structure construction started under Julius Caesar but was completed under Augustus. It was this building that shows the integration of new concrete building techniques of Augustus's architects as opposed to those of Caesar. The Theatre of Marcellus uses a variety of materials that aid in the growth of the concrete revolution using readily available volcanic stones such as Tuscolo tuff and Tufo Lionato as aggregates in pozzolanic concretes.

These newly concocted recipes for concrete provided durability to walls and barrelled vaults as well as a unique aesthetic appeal. The integrated stone and masonry design illustrate a refinement that came with the concrete revolution as a result of the new techniques and styles developed under Augustus. The craftsmanship of the Theatre Marcellus demonstrated a skilled employment as well as rigorous technical supervision.