Have a deep view into what people are curious about.

🔗 Writing systems

Shorthand is an abbreviated symbolic writing method that increases speed and brevity of writing as compared to longhand, a more common method of writing a language. The process of writing in shorthand is called stenography, from the Greek stenos (narrow) and graphein (to write). It has also been called brachygraphy, from Greek brachys (short), and tachygraphy, from Greek tachys (swift, speedy), depending on whether compression or speed of writing is the goal.

Many forms of shorthand exist. A typical shorthand system provides symbols or abbreviations for words and common phrases, which can allow someone well-trained in the system to write as quickly as people speak. Abbreviation methods are alphabet-based and use different abbreviating approaches. Many journalists use shorthand writing to quickly take notes at press conferences or other similar scenarios. In the computerized world, several autocomplete programs, standalone or integrated in text editors, based on word lists, also include a shorthand function for frequently used phrases.

Shorthand was used more widely in the past, before the invention of recording and dictation machines. Shorthand was considered an essential part of secretarial training and police work and was useful for journalists. Although the primary use of shorthand has been to record oral dictation or discourse, some systems are used for compact expression. For example, healthcare professionals may use shorthand notes in medical charts and correspondence. Shorthand notes are typically temporary, intended either for immediate use or for later typing, data entry, or (mainly historically) transcription to longhand. Longer term uses do exist, such as encipherment: diaries (like that of Samuel Pepys) are a common example.

🔗 Computer Security 🔗 Computer Security/Computing

Zombie Zero is an attack vector where a cyber attacker utilized malware that was clandestinely embedded in new barcode readers which were manufactured overseas.

It remains unknown if this attack was promulgated by organized crime or a nation state. Clearly there was significant planning and investment in order to design the malware, and then embed it into the hardware within the barcode scanner. Internet of things (IoT) devices may be similarly preinstalled with malware that can capture the network passwords and then open a backdoor to attackers. Given the high volume of these devices manufactured overseas high caution is to be exercised before placing these devices on corporate or government networks.

The photoacoustic effect or optoacoustic effect is the formation of sound waves following light absorption in a material sample. In order to obtain this effect the light intensity must vary, either periodically (modulated light) or as a single flash (pulsed light). The photoacoustic effect is quantified by measuring the formed sound (pressure changes) with appropriate detectors, such as microphones or piezoelectric sensors. The time variation of the electric output (current or voltage) from these detectors is the photoacoustic signal. These measurements are useful to determine certain properties of the studied sample. For example, in photoacoustic spectroscopy, the photoacoustic signal is used to obtain the actual absorption of light in either opaque or transparent objects. It is useful for substances in extremely low concentrations, because very strong pulses of light from a laser can be used to increase sensitivity and very narrow wavelengths can be used for specificity. Furthermore, photoacoustic measurements serve as a valuable research tool in the study of the heat evolved in photochemical reactions (see: photochemistry), particularly in the study of photosynthesis.

Most generally, electromagnetic radiation of any kind can give rise to a photoacoustic effect. This includes the whole range of electromagnetic frequencies, from gamma radiation and X-rays to microwave and radio. Still, much of the reported research and applications, utilizing the photoacoustic effect, is concerned with the near ultraviolet/visible and infrared spectral regions.

🔗 Technology 🔗 Business 🔗 Marketing & Advertising

The theory of constraints (TOC) is a management paradigm that views any manageable system as being limited in achieving more of its goals by a very small number of constraints. There is always at least one constraint, and TOC uses a focusing process to identify the constraint and restructure the rest of the organization around it. TOC adopts the common idiom "a chain is no stronger than its weakest link". That means that organizations and processes are vulnerable because the weakest person or part can always damage or break them, or at least adversely affect the outcome.

🔗 India 🔗 Board and table games

Ganjifa, Ganjapa or Gânjaphâ, is a card game and type of playing cards that are most associated with Persia and India. After Ganjifa cards fell out of use in Iran before the twentieth century, India became the last country to produce them. The form prevalent in Odisha is Ganjapa.

🔗 Mammals

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.

🔗 United States 🔗 Donald Trump 🔗 Taiwan

The Trump–Tsai call was a telephone conversation between the U.S President-elect Donald Trump and the President of Taiwan Tsai Ing-wen which took place on December 2, 2016. This event marked the first time since 1979 that a U.S. president or President-elect had directly spoken with a ROC President. In the call, Tsai congratulated Trump for his victory in the presidential election. The two leaders spoke for around 10 minutes, focusing on politics, economy, and security in Asia-Pacific. Following the call, Trump publicized this on Twitter and Facebook and said thank you to "the President of Taiwan". After Trump's transition team confirmed the event, the Presidential Office of Taiwan released a statement about the content of the call.

Several prominent Republicans praised the call between the two leaders, saying that the United States needs no more pressure from the government of the People's Republic of China (commonly called "China"), which does not recognize the ROC government and claims Taiwan is part of its territory. Some commentators from U.S. media outlets said that the call humiliated Beijing as it seemed a violation of a diplomatic practice. Other media and comments criticized the One-China policy, saying that Trump's move was morally right and strategically correct for American interests. Wang Yi, the Foreign Minister of the People's Republic of China subsequently responded that this event is only a "small trick" played by Taiwan and will not change the One-China Policy. A spokesperson for the Presidential Office in Taipei expressed that there is no conflict between the Cross-Strait relations and the Taiwan–U.S. relations. The Obama administration stated that the U.S. would uphold the One-China Policy. Trump later responded by saying that the U.S. did not have to follow that policy.

🔗 Physics

In quantum field theory, a false vacuum is a hypothetical vacuum that is relatively stable, but not in the most stable state possible. In this condition it is called metastable. It may last for a very long time in this state, but could eventually decay to the more stable one, an event known as false vacuum decay. The most common suggestion of how such a decay might happen in our universe is called bubble nucleation – if a small region of the universe by chance reached a more stable vacuum, this "bubble" (also called "bounce") would spread.

A false vacuum exists at a local minimum of energy and is therefore not completely stable, in contrast to a true vacuum, which exists at a global minimum and is stable.

🔗 United States 🔗 Trains 🔗 United States/Ohio 🔗 Trains/Rapid transit 🔗 United States/Cincinnati

The Cincinnati Subway is a set of incomplete, derelict tunnels and stations for a rapid transit system beneath the streets of Cincinnati, Ohio. Although it is only a little over 2 miles in length, it is the largest abandoned subway tunnel system in the United States. Construction began in the early 1900s as an upgrade to the Cincinnati streetcar system, but was abandoned due to escalating costs, the collapse of funding amidst political bickering, and the Great Depression during the 1920s and 1930s.

In 1928, the construction of the subway system in Cincinnati was indefinitely canceled. There are no plans to revive the project.

🔗 Mathematics 🔗 Statistics

Itô calculus, named after Kiyosi Itô, extends the methods of calculus to stochastic processes such as Brownian motion (see Wiener process). It has important applications in mathematical finance and stochastic differential equations.

The central concept is the Itô stochastic integral, a stochastic generalization of the Riemann–Stieltjes integral in analysis. The integrands and the integrators are now stochastic processes:

${\displaystyle Y_{t}=\int _{0}^{t}H_{s}\,dX_{s},}$

where H is a locally square-integrable process adapted to the filtration generated by X (Revuz & Yor 1999, Chapter IV), which is a Brownian motion or, more generally, a semimartingale. The result of the integration is then another stochastic process. Concretely, the integral from 0 to any particular t is a random variable, defined as a limit of a certain sequence of random variables. The paths of Brownian motion fail to satisfy the requirements to be able to apply the standard techniques of calculus. So with the integrand a stochastic process, the Itô stochastic integral amounts to an integral with respect to a function which is not differentiable at any point and has infinite variation over every time interval. The main insight is that the integral can be defined as long as the integrand H is adapted, which loosely speaking means that its value at time t can only depend on information available up until this time. Roughly speaking, one chooses a sequence of partitions of the interval from 0 to t and constructs Riemann sums. Every time we are computing a Riemann sum, we are using a particular instantiation of the integrator. It is crucial which point in each of the small intervals is used to compute the value of the function. The limit then is taken in probability as the mesh of the partition is going to zero. Numerous technical details have to be taken care of to show that this limit exists and is independent of the particular sequence of partitions. Typically, the left end of the interval is used.

Important results of Itô calculus include the integration by parts formula and Itô's lemma, which is a change of variables formula. These differ from the formulas of standard calculus, due to quadratic variation terms.

In mathematical finance, the described evaluation strategy of the integral is conceptualized as that we are first deciding what to do, then observing the change in the prices. The integrand is how much stock we hold, the integrator represents the movement of the prices, and the integral is how much money we have in total including what our stock is worth, at any given moment. The prices of stocks and other traded financial assets can be modeled by stochastic processes such as Brownian motion or, more often, geometric Brownian motion (see Black–Scholes). Then, the Itô stochastic integral represents the payoff of a continuous-time trading strategy consisting of holding an amount H_t of the stock at time t. In this situation, the condition that H is adapted corresponds to the necessary restriction that the trading strategy can only make use of the available information at any time. This prevents the possibility of unlimited gains through clairvoyance: buying the stock just before each uptick in the market and selling before each downtick. Similarly, the condition that H is adapted implies that the stochastic integral will not diverge when calculated as a limit of Riemann sums (Revuz & Yor 1999, Chapter IV).