Sometimes called historical reasoning skills, historical thinking skills are frequently described in contrast to history content such as names, dates, and places. This dichotomous presentation is often misinterpreted as a claim for superiority of one form of knowing over the other. In fact, the distinction is generally made to underscore the importance of developing thinking skills that can be applied when individuals encounter any history content. Most educators agree that together, history content—or facts about the past—and historical thinking skills enable students to interpret, analyze and use information about past events.

A good site to start: historyisaweapon.com

]]>In this episode, physicist Wal Thornhill explores whether consensus science is leading toward or away from a better understanding of climate change.

]]>If crystals have an atomic structure that repeats in space, like the carbon lattice of a diamond, why can’t crystals also have a structure that repeats in time? That is, a time crystal?

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Two groups followed Yao’s blueprint and have already created the first-ever time crystals. The groups at the University of Maryland and Harvard University reported their successes, using two totally different setups, in papers posted online last year, and have submitted the results for publication. Yao is a co-author on both papers.

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Time crystals repeat in time because they are kicked periodically, sort of like tapping Jell-O repeatedly to get it to jiggle, Yao said. The big breakthrough, he argues, is less that these particular crystals repeat in time than that they are the first of a large class of new materials that are intrinsically out of equilibrium, unable to settle down to the motionless equilibrium of, for example, a diamond or ruby.

Read more at phys.org

Symmetry breaking is one of the most profound concepts in physics. It is behind the formation of crystals, but also appears in many other fundamental processes.

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The prediction, realisation and discovery of time crystals opens a new chapter in quantum mechanics, with questions about the properties of this newly found state of matter and whether time crystals might occur in nature.

Read more at phys.org

]]>The United States military focus tends to favor technology, and hence tends to extend into the realms of electronic warfare, cyberwarfare, information assurance and computer network operations, attack and defense.

Most of the rest of the world use the much broader term of “Information Operations” which, although making use of technology, focuses on the more human-related aspects of information use, including (amongst many others) social network analysis, decision analysis and the human aspects of command and control.

]]>Typical application of interferometry can be found in physics and astronomy, for example by using high-resolution observations using the technique of aperture synthesis, mixing signals from a cluster of comparatively small telescopes rather than a single very expensive monolithic telescope.

Also in biology a kind of optical interferometry is used, which provides sensitive metrology capabilities for the measurement of biomolecules, subcellular components, cells and tissues.

]]>Probability is the measure of the likelihood that an event will occur. Probability is quantified as a number between 0 and 1 (where 0 indicates impossibility and 1 indicates certainty). The higher the probability of an event, the more certain that the event will occur. A simple example is the tossing of a fair (unbiased) coin. Since the coin is unbiased, the two outcomes (“head” and “tail”) are both equally probable; the probability of “head” equals the probability of “tail”. Since no other outcomes are possible, the probability is 1/2 (or 50%), of either “head” or “tail”. In other words, the probability of “head” is 1 out of 2 outcomes and the probability of “tail” is also 1 out of 2 outcomes, expressed as 0.5 when converted to decimal, with the above-mentioned quantification system. This type of probability is also called a priori probability.

**Probability theory**

Probability theory is the branch of mathematics concerned with probability, the analysis of random phenomena. The central objects of probability theory are random variables, stochastic processes, and events: mathematical abstractions of non-deterministic events or measured quantities that may either be single occurrences or evolve over time in an apparently random fashion.

It is not possible to predict precisely results of random events. However, if a sequence of individual events, such as coin flipping or the roll of dice, is influenced by other factors, such as friction, it will exhibit certain patterns, which can be studied and predicted. Two representative mathematical results describing such patterns are the law of large numbers and the central limit theorem.

As a mathematical foundation for statistics, probability theory is essential to many human activities that involve quantitative analysis of large sets of data. Methods of probability theory also apply to descriptions of complex systems given only partial knowledge of their state, as in statistical mechanics.

**Probability theory and Quantum mechanics**

Probability theory is required to describe quantum phenomena. A revolutionary discovery of early 20th century physics was the random character of all physical processes that occur at sub-atomic scales and are governed by the laws of quantum mechanics. The objective wave function evolves deterministically but, according to the Copenhagen interpretation, it deals with *probabilities of observing*, the outcome being explained by a *wave function collapse* when an *observation* is made.

**Etymology of the word probability**

The word probability derives from the Latin probabilitas, which can also mean “*probity*“, *a measure of the authority of a witness* in a legal case in Europe, and often correlated with the witness’s nobility.

From the point of view of idealism this makes really sense, because a observer has indeed a certain authority over the observed system, where the probability is changed by the act of observing.

**See also:**

– Quantum Zeno Effect and the Burning Bush

A field is a mathematical entity that exists throughout space and time. A classical field is simply a function that has a numerical value at each point in spacetime. Think, for example, of the temperature in a room: in principle you can define a function T(x,t) that gives the temperature at any point x in the room at any time t. Fields are defined similarly.

A quantum field is what you get when you “quantize” a classical field. In this process, the field becomes a function that gives an operator at each point in spacetime, instead of a numerical value. I won’t get into detail about the mathematics of quantization or what it means to have a operator-valued function.

A particle is an excited state of a field. What this means is (roughly) that a particular system may be in a vacuum state (0 particles) or in various excited states of the field (1 or more particles). The field operators may be used to create or destroy excited states (and thus, particles) at particular points in spacetime.

We call the particle associated with a field the “quantum” (plural “quanta”) of that field. So, the photon is the quantum of the electromagnetic field, the electron and the positron are the quanta of the electron field, and so on.

*Therefore, the field is the more “fundamental” entity;* the field exists *everywhere*, and the particles associated with it are arbitrarily created or destroyed by the field operators whenever they are needed, or even just at random (by “quantum fluctuations”).

**See also:**

– Reality is created in a Consensus Agreement of all Participants

Depending on the regime of measurement, a suppression or enhancement of the decay rate can be observed. This means depending on the frequency of measurements the decay is suppressed or enhanced.

]]>The key to observing the Zeno and Anti-Zeno effects

is the ability to measure the state of the system in order

to repeatedly redefine a new initial state.Source: Observation of the Quantum Zeno and Anti-Zeno effects in an unstable system

For instance, the 72 cancer therapies approved between 2002 and 2014 only bought patients an extra 2.1 months of life compared with older drugs, researchers have found. And there’s no evidence that two-thirds of the drugs approved in the last two years improve survival at all.

Yet, that doesn’t keep some of those drugs from coming with heavy price tags and concerning side-effects. Among cancer drugs approved in 2016, the average cost for a year’s worth of treatment was $171,000. And like survival, side-effects aren’t always improved with the higher prices. For example, among thyroid cancer patients, those taking the most expensive drug, cabozantinib, had the worst reports of side effects, including diarrhea, fatigue, sleep disturbance, distress, and difficulty remembering.

Read more on arstechnica.com.

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