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Post-Impressionism

Post-Impressionism (also spelled Postimpressionism) was a predominantly French art movement that developed roughly between 1886 and 1905, from the last Impressionist exhibition to the birth of Fauvism. Post-Impressionism emerged as a reaction against Impressionists' concern for the naturalistic depiction of light and colour. Its broad emphasis on abstract qualities or symbolic content means Post-Impressionism encompasses Les Nabis, Neo-Impressionism, Symbolism, Cloisonnism, the Pont-Aven School, and Synthetism, along with some later Impressionists' work. The movement's principal artists were Paul Cézanne (known as the father of Post-Impressionism), Paul Gauguin, Vincent van Gogh and Georges Seurat.

The term Post-Impressionism was first used by art critic Roger Fry in 1906. Critic Frank Rutter in a review of the Salon d'Automne published in Art News, 15 October 1910, described Othon Friesz as a "post-impressionist leader"; there was also an advert for the show The Post-Impressionists of France. Three weeks later, Roger Fry used the term again when he organised the 1910 exhibition Manet and the Post-Impressionists, defining it as the development of French art since Édouard Manet.

Post-Impressionists extended Impressionism while rejecting its limitations: they continued using vivid colours, sometimes using impasto (thick application of paint) and painting from life, but were more inclined to emphasize geometric forms, distort form for expressive effect, and use unnatural or modified colour.

Overview
The Post-Impressionists were dissatisfied with what they felt was the triviality of subject matter and the loss of structure in Impressionist paintings, though they did not agree on the way forward. Georges Seurat and his followers concerned themselves with pointillism, the systematic use of tiny dots of colour. Paul Cézanne set out to restore a sense of order and structure to painting, to "make of Impressionism something solid and durable, like the art of the museums". He achieved this by reducing objects to their basic shapes while retaining the saturated colours of Impressionism. The Impressionist Camille Pissarro experimented with Neo-Impressionist ideas between the mid-1880s and the early 1890s. Discontented with what he referred to as romantic Impressionism, he investigated pointillism, which he called scientific Impressionism, before returning to a purer Impressionism in the last decade of his life. Vincent van Gogh often used vibrant colour and conspicuous brushstrokes to convey his feelings and his state of mind.

Although they often exhibited together, Post-Impressionist artists were not in agreement concerning a cohesive movement. Yet, the abstract concerns of harmony and structural arrangement, in the work of all these artists, took precedence over naturalism. Artists such as Seurat adopted a meticulously scientific approach to colour and composition.

Defining Post-Impressionism
The term was used in 1906, and again in 1910 by Roger Fry in the title of an exhibition of modern French painters: Manet and the Post-Impressionists, organized by Fry for the Grafton Galleries in London. Three weeks before Fry's show, art critic Frank Rutter had put the term Post-Impressionist in print in Art News of 15 October 1910, during a review of the Salon d'Automne, where he described Othon Friesz as a "post-impressionist leader"; there was also an advert in the journal for the show The Post-Impressionists of France.

Most of the artists in Fry's exhibition were younger than the Impressionists. Fry later explained: "For purposes of convenience, it was necessary to give these artists a name, and I chose, as being the vaguest and most non-committal, the name of Post-Impressionism. This merely stated their position in time relatively to the Impressionist movement." John Rewald limited the scope to the years between 1886 and 1892 in his pioneering publication on Post-Impressionism: From Van Gogh to Gauguin (1956). Rewald considered this a continuation of his 1946 study, History of Impressionism, and pointed out that a "subsequent volume dedicated to the second half of the post-impressionist period": Post-Impressionism: From Gauguin to Matisse, was to follow. This volume would extend the period covered to other artistic movements derived from Impressionism, though confined to the late 19th and early 20th centuries. Rewald focused on such outstanding early Post-Impressionists active in France as van Gogh, Gauguin, Seurat, and Redon. He explored their relationships as well as the artistic circles they frequented (or were in opposition to), including: Furthermore, in his introduction to Post-Impressionism, Rewald opted for a second volume featuring Toulouse-Lautrec, Henri Rousseau "le Douanier", Les Nabis and Cézanne as well as the Fauves, the young Picasso and Gauguin's last trip to the South Seas; it was to expand the period covered at least into the first decade of the 20th century—yet this second volume remained unfinished.
 * Neo-Impressionism: ridiculed by contemporary art critics as well as artists as Pointillism; Seurat and Signac would have preferred other terms: Divisionism for example
 * Cloisonnism: a short-lived term introduced in 1888 by the art critic Édouard Dujardin, was to promote the work of Louis Anquetin, and was later also applied to contemporary works of his friend Émile Bernard
 * Synthetism: another short-lived term coined in 1889 to distinguish recent works of Gauguin and Bernard from that of more traditional Impressionists exhibiting with them at the Café Volpini.
 * Pont-Aven School: implying little more than that the artists involved had been working for a while in Pont-Aven or elsewhere in Brittany.
 * Symbolism: a term highly welcomed by vanguard critics in 1891, when Gauguin dropped Synthetism as soon as he was acclaimed to be the leader of Symbolism in painting.

Reviews and adjustments
Rewald wrote that "the term 'Post-Impressionism' is not a very precise one, though a very convenient one"; convenient, when the term is by definition limited to French visual arts derived from Impressionism since 1886. Rewald's approach to historical data was narrative rather than analytic, and beyond this point he believed it would be sufficient to "let the sources speak for themselves."

Rival terms like Modernism or Symbolism were never as easy to handle, for they covered literature, architecture and other arts as well, and they expanded to other countries.

 * Modernism, thus, is now considered to be the central movement within international western civilization with its original roots in France, going back beyond the French Revolution to the Age of Enlightenment.
 * Symbolism, however, is considered to be a concept which emerged a century later in France, and implied an individual approach. Local national traditions as well as individual settings therefore could stand side by side, and from the very beginning a broad variety of artists practicing some kind of symbolic imagery, ranged between extreme positions: The Nabis for example united to find synthesis of tradition and brand new form, while others kept to traditional, more or less academic forms, when they were looking for fresh contents: Symbolism is therefore often linked to fantastic, esoteric, erotic and other non-realist subject matter.

To meet the recent discussion, the connotations of the term 'Post-Impressionism' were challenged again: Alan Bowness and his collaborators expanded the period covered forward to 1914 and the beginning of World War I, but limited their approach widely on the 1890s to France. Other European countries are pushed back to standard connotations, and Eastern Europe is completely excluded.

So, while a split may be seen between classical 'Impressionism' and 'Post-Impressionism' in 1886, the end and the extent of 'Post-Impressionism' remains under discussion. For Bowness and his contributors as well as for Rewald, 'Cubism' was an absolutely fresh start, and so Cubism has been seen in France since the beginning, and later in England. Meanwhile, Eastern European artists, however, did not care so much for western traditions, and proceeded to manners of painting called abstract and suprematic—terms expanding far into the 20th century.

According to the present state of discussion, Post-Impressionism is a term best used within Rewald's definition in a strictly historical manner, concentrating on French art between 1886 and 1914, and re-considering the altered positions of impressionist painters like Claude Monet, Camille Pissarro, Auguste Renoir, and others—as well as all new schools and movements at the turn of the century: from Cloisonnism to Cubism. The declarations of war, in July/August 1914, indicate probably far more than the beginning of a World War—they signal a major break in European cultural history, too.

Along with general art history information given about "Post-Impressionism" works, there are many museums that offer additional history, information and gallery works, both online and in house, that can help viewers understand a deeper meaning of "Post-Impressionism" in terms of fine art and traditional art applications.

Post-Impression in specific countries
The Advent of Modernism: Post-impressionism and North American Art, 1900-1918 by Peter Morrin, Judith Zilczer, and William C. Agee, the catalogue for an exhibition at the High Museum of Art, Atlanta in 1986, gave a major overview of Post-Impressionism in North America.

Canada
Canadian Post-Impressionism is an offshoot of Post-Impressionism. In 1913, the Art Association of Montreal's Spring show included the work of Randolph Hewton, A. Y. Jackson and John Lyman: it was reviewed with sharp criticism by the Montreal Daily Witness and the Montreal Daily Star. Post-Impressionism was extended to include a painting by Lyman, who had studied with Matisse. Lyman wrote in defence of the term and defined it. He referred to the British show which he described as a great exhibition of modern art.

Canadian artists and exhibitions
A wide and diverse variety of artists are called by this name in Canada. Among them are James Wilson Morrice, John Lyman, David Milne, and Tom Thomson, members of the Group of Seven, and Emily Carr. In 2001, the Robert McLaughlin Gallery in Oshawa organized the travelling exhibition The Birth of the Modern: Post-Impressionism in Canada, 1900-1920.

title: Post-Impressionism


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Efficient-market hypothesis

The efficient-market hypothesis (EMH) is a hypothesis in financial economics that states that asset prices reflect all available information. A direct implication is that it is impossible to "beat the market" consistently on a risk-adjusted basis since market prices should only react to new information.

Because the EMH is formulated in terms of risk adjustment, it only makes testable predictions when coupled with a particular model of risk. As a result, research in financial economics since at least the 1990s has focused on market anomalies, that is, deviations from specific models of risk.

The idea that financial market returns are difficult to predict goes back to Bachelier, Mandelbrot, and Samuelson, but is closely associated with Eugene Fama, in part due to his influential 1970 review of the theoretical and empirical research. The EMH provides the basic logic for modern risk-based theories of asset prices, and frameworks such as consumption-based asset pricing and intermediary asset pricing can be thought of as the combination of a model of risk with the EMH.

Many decades of empirical research on return predictability has found mixed evidence. Research in the 1950s and 1960s often found a lack of predictability (e.g. Ball and Brown 1968; Fama, Fisher, Jensen, and Roll 1969), yet the 1980s-2000s saw an explosion of discovered return predictors (e.g. Rosenberg, Reid, and Lanstein 1985; Campbell and Shiller 1988; Jegadeesh and Titman 1993). Since the 2010s, studies have often found that return predictability has become more elusive, as predictability fails to work out-of-sample (Goyal and Welch 2008), or has been weakened by advances in trading technology and investor learning (Chordia, Subrahmanyam, and Tong 2014; McLean and Pontiff 2016; Martineau 2021).

Theoretical background
Suppose that a piece of information about the value of a stock (say, about a future merger) is widely available to investors. If the price of the stock does not already reflect that information, then investors can trade on it, thereby moving the price until the information is no longer useful for trading.

Note that this thought experiment does not necessarily imply that stock prices are unpredictable. For example, suppose that the piece of information in question says that a financial crisis is likely to come soon. Investors typically do not like to hold stocks during a financial crisis, and thus investors may sell stocks until the price drops enough so that the expected return compensates for this risk.

How efficient markets are (and are not) linked to the random walk theory can be described through the fundamental theorem of asset pricing. This theorem provides mathematical predictions regarding the price of a stock, assuming that there is no arbitrage, that is, assuming that there is no risk-free way to trade profitably. Formally, if arbitrage is impossible, then the theorem predicts that the price of a stock is the discounted value of its future price and dividend:

 * $$P_t = E_t[M_{t+1} (P_{t+1}+D_{t+1})]$$

where $$E_{t}$$ is the expected value given information at time $$t$$, $$M_{t+1}$$ is the stochastic discount factor, and $$D_{t+1}$$is the dividend the stock pays next period.

Note that this equation does not generally imply a random walk. However, if we assume the stochastic discount factor is constant and the time interval is short enough so that no dividend is being paid, we have

 * $$P_t = M E_t[P_{t+1}]$$.

Taking logs and assuming that the Jensen's inequality term is negligible, we have

 * $$\log P_t = \log M + E_t [\log P_{t+1}]$$

which implies that the log of stock prices follows a random walk (with a drift).

Although the concept of an efficient market is similar to the assumption that stock prices follow:

$$E[S_{t+1}|S_{t}]=S_{t}$$

which follows a martingale, the EMH does not always assume that stocks follow a martingale.

Empirical studies
Research by Alfred Cowles in the 1930s and 1940s suggested that professional investors were in general unable to outperform the market. During the 1930s-1950s empirical studies focused on time-series properties, and found that US stock prices and related financial series followed a random walk model in the short-term. While there is some predictability over the long-term, the extent to which this is due to rational time-varying risk premia as opposed to behavioral reasons is a subject of debate. In their seminal paper, Fama, Fisher, Jensen, and Roll (1969) propose the event study methodology and show that stock prices on average react before a stock split, but have no movement afterwards.

Weak, semi-strong, and strong-form tests
In Fama's influential 1970 review paper, he categorized empirical tests of efficiency into "weak-form", "semi-strong-form", and "strong-form" tests.

These categories of tests refer to the information set used in the statement "prices reflect all available information." Weak-form tests study the information contained in historical prices. Semi-strong form tests study information (beyond historical prices) which is publicly available. Strong-form tests regard private information.

Historical background
Benoit Mandelbrot claimed the efficient markets theory was first proposed by the French mathematician Louis Bachelier in 1900 in his PhD thesis "The Theory of Speculation" describing how prices of commodities and stocks varied in markets. It has been speculated that Bachelier drew ideas from the random walk model of Jules Regnault, but Bachelier did not cite him, and Bachelier's thesis is now considered pioneering in the field of financial mathematics. It is commonly thought that Bachelier's work gained little attention and was forgotten for decades until it was rediscovered in the 1950s by Leonard Savage, and then become more popular after Bachelier's thesis was translated into English in 1964. But the work was never forgotten in the mathematical community, as Bachelier published a book in 1912 detailing his ideas, which was cited by mathematicians including Joseph L. Doob, William Feller and Andrey Kolmogorov. The book continued to be cited, but then starting in the 1960s the original thesis by Bachelier began to be cited more than his book when economists started citing Bachelier's work.

The concept of market efficiency had been anticipated at the beginning of the century in the dissertation submitted by Bachelier (1900) to the Sorbonne for his PhD in mathematics. In his opening paragraph, Bachelier recognizes that "past, present and even discounted future events are reflected in market price, but often show no apparent relation to price changes".

The efficient markets theory was not popular until the 1960s when the advent of computers made it possible to compare calculations and prices of hundreds of stocks more quickly and effortlessly. In 1945, F.A. Hayek argued in his article The Use of Knowledge in Society that markets were the most effective way of aggregating the pieces of information dispersed among individuals within a society. Given the ability to profit from private information, self-interested traders are motivated to acquire and act on their private information. In doing so, traders contribute to more and more efficient market prices. In the competitive limit, market prices reflect all available information and prices can only move in response to news. Thus there is a very close link between EMH and the random walk hypothesis.

Early theories posited that predicting stock prices is unfeasible, as they depend on fresh information or news rather than existing or historical prices. Therefore, stock prices are thought to fluctuate randomly, and their predictability is believed to be no better than a 50% accuracy rate.

The efficient-market hypothesis emerged as a prominent theory in the mid-1960s. Paul Samuelson had begun to circulate Bachelier's work among economists. In 1964 Bachelier's dissertation along with the empirical studies mentioned above were published in an anthology edited by Paul Cootner. In 1965, Eugene Fama published his dissertation arguing for the random walk hypothesis. Also, Samuelson published a proof showing that if the market is efficient, prices will exhibit random-walk behavior. This is often cited in support of the efficient-market theory, by the method of affirming the consequent, however in that same paper, Samuelson warns against such backward reasoning, saying "From a nonempirical base of axioms you never get empirical results." In 1970, Fama published a review of both the theory and the evidence for the hypothesis. The paper extended and refined the theory, included the definitions for three forms of financial market efficiency: weak, semi-strong and strong (see above).

Criticism

Investors, including the likes of Warren Buffett, George Soros, and researchers have disputed the efficient-market hypothesis both empirically and theoretically. Behavioral economists attribute the imperfections in financial markets to a combination of cognitive biases such as overconfidence, overreaction, representative bias, information bias, and various other predictable human errors in reasoning and information processing. These have been researched by psychologists such as Daniel Kahneman, Amos Tversky and Paul Slovic and economist Richard Thaler.

Empirical evidence has been mixed, but has generally not supported strong forms of the efficient-market hypothesis. According to Dreman and Berry, in a 1995 paper, low P/E (price-to-earnings) stocks have greater returns. In an earlier paper, Dreman also refuted the assertion by Ray Ball that these higher returns could be attributed to higher beta leading to a failure to correctly risk-adjust returns; Dreman's research had been accepted by efficient market theorists as explaining the anomaly in neat accordance with modern portfolio theory.

Behavioral psychology
Behavioral psychology approaches to stock market trading are among some of the alternatives to EMH (investment strategies such as momentum trading seek to exploit exactly such inefficiencies). However, Nobel Laureate co-founder of the programme Daniel Kahneman —announced his skepticism of investors beating the market: "They're just not going to do it. It's just not going to happen." Indeed, defenders of EMH maintain that behavioral finance strengthens the case for EMH in that it highlights biases in individuals and committees and not competitive markets. For example, one prominent finding in behavioral finance is that individuals employ hyperbolic discounting. It is demonstrably true that bonds, mortgages, annuities and other similar obligations subject to competitive market forces do not. Any manifestation of hyperbolic discounting in the pricing of these obligations would invite arbitrage thereby quickly eliminating any vestige of individual biases. Similarly, diversification, derivative securities and other hedging strategies assuage if not eliminate potential mispricings from the severe risk-intolerance (loss aversion) of individuals underscored by behavioral finance. On the other hand, economists, behavioral psychologists and mutual fund managers are drawn from the human population and are therefore subject to the biases that behavioralists showcase. By contrast, the price signals in markets are far less subject to individual biases highlighted by the Behavioral Finance programme. Richard Thaler has started a fund based on his research on cognitive biases. In a 2008 report he identified complexity and herd behavior as central to the global financial crisis of 2008.

Further empirical work has highlighted the impact transaction costs have on the concept of market efficiency, with much evidence suggesting that any anomalies pertaining to market inefficiencies are the result of a cost benefit analysis made by those willing to incur the cost of acquiring the valuable information in order to trade on it. Additionally, the concept of liquidity is a critical component to capturing "inefficiencies" in tests for abnormal returns. Any test of this proposition faces the joint hypothesis problem, where it is impossible to ever test for market efficiency, since to do so requires the use of a measuring stick against which abnormal returns are compared —one cannot know if the market is efficient if one does not know if a model correctly stipulates the required rate of return. Consequently, a situation arises where either the asset pricing model is incorrect or the market is inefficient, but one has no way of knowing which is the case.

The performance of stock markets is correlated with the amount of sunshine in the city where the main exchange is located.

EMH anomalies and rejection of the Capital Asset Pricing Model (CAPM)
While event studies of stock splits are consistent with the EMH (Fama, Fisher, Jensen, and Roll, 1969), other empirical analyses have found problems with the efficient-market hypothesis. Early examples include the observation that small neglected stocks and stocks with high book-to-market (low price-to-book) ratios (value stocks) tended to achieve abnormally high returns relative to what could be explained by the CAPM. Further tests of portfolio efficiency by Gibbons, Ross and Shanken (1989) (GJR) led to rejections of the CAPM, although tests of efficiency inevitably run into the joint hypothesis problem (see Roll's critique).

Following GJR's results and mounting empirical evidence of EMH anomalies, academics began to move away from the CAPM towards risk factor models such as the Fama-French 3 factor model. These risk factor models are not properly founded on economic theory (whereas CAPM is founded on Modern Portfolio Theory), but rather, constructed with long-short portfolios in response to the observed empirical EMH anomalies. For instance, the "small-minus-big" (SMB) factor in the FF3 factor model is simply a portfolio that holds long positions on small stocks and short positions on large stocks to mimic the risks small stocks face. These risk factors are said to represent some aspect or dimension of undiversifiable systematic risk which should be compensated with higher expected returns. Additional popular risk factors include the "HML" value factor (Fama and French, 1993); "MOM" momentum factor (Carhart, 1997); "ILLIQ" liquidity factors (Amihud et al. 2002). See also Robert Haugen.

View of some journalists, economists, and investors
Economists Matthew Bishop and Michael Green claim that full acceptance of the hypothesis goes against the thinking of Adam Smith and John Maynard Keynes, who both believed irrational behavior had a real impact on the markets.

Economist John Quiggin has claimed that "Bitcoin is perhaps the finest example of a pure bubble", and that it provides a conclusive refutation of EMH. While other assets that have been used as currency (such as gold, tobacco) have value or utility independent of people's willingness to accept them as payment, Quiggin argues that "in the case of Bitcoin there is no source of value whatsoever" and thus Bitcoin should be priced at zero or worthless.

Tshilidzi Marwala surmised that artificial intelligence (AI) influences the applicability of the efficient market hypothesis in that the greater amount of AI-based market participants, the more efficient the markets become.

Warren Buffett has also argued against EMH, most notably in his 1984 presentation "The Superinvestors of Graham-and-Doddsville". He says preponderance of value investors among the world's money managers with the highest rates of performance rebuts the claim of EMH proponents that luck is the reason some investors appear more successful than others. Nonetheless, Buffett has recommended index funds that aim to track average market returns for most investors. Buffett's business partner Charlie Munger has stated the EMH is "obviously roughly correct", in that a hypothetical average investor will tend towards average results "and it's quite hard for anybody to [consistently] beat the market by significant margins". However, Munger also believes "extreme" commitment to the EMH is "bonkers", as the theory's originators were seduced by an "intellectually consistent theory that allowed them to do pretty mathematics [yet] the fundamentals did not properly tie to reality."

Burton Malkiel in his A Random Walk Down Wall Street (1973) argues that "the preponderance of statistical evidence" supports EMH, but admits there are enough "gremlins lurking about" in the data to prevent EMH from being conclusively proved.

In his book The Reformation in Economics, economist and financial analyst Philip Pilkington has argued that the EMH is actually a tautology masquerading as a theory. He argues that, taken at face value, the theory makes the banal claim that the average investor will not beat the market average—which is a tautology. When pressed on this point, Pinkington argues that EMH proponents will usually say that any actual investor will converge with the average investor given enough time and so no investor will beat the market average. But Pilkington points out that when proponents of the theory are presented with evidence that a small minority of investors do, in fact, beat the market over the long-run, these proponents then say that these investors were simply 'lucky'. Pilkington argues that introducing the idea that anyone who diverges from the theory is simply 'lucky' insulates the theory from falsification and so, drawing on the philosopher of science and critic of neoclassical economics Hans Albert, Pilkington argues that the theory falls back into being a tautology or a pseudoscientific construct.

Nobel Prize-winning economist Paul Samuelson argued that the stock market is "micro efficient" but not "macro efficient": the EMH is much better suited for individual stocks than it is for the aggregate stock market as a whole. Research based on regression and scatter diagrams, published in 2005, has strongly supported Samuelson's dictum.

Peter Lynch, a mutual fund manager at Fidelity Investments who consistently more than doubled market averages while managing the Magellan Fund, has argued that the EMH is contradictory to the random walk hypothesis—though both concepts are widely taught in business schools without seeming awareness of a contradiction. If asset prices are rational and based on all available data as the efficient market hypothesis proposes, then fluctuations in asset price are not random. But if the random walk hypothesis is valid, then asset prices are not rational.

Joel Tillinghast, also a fund manager at Fidelity with a long history of outperforming a benchmark, has written that the core arguments of the EMH are "more true than not" and he accepts a "sloppy" version of the theory allowing for a margin of error. But he also contends the EMH is not completely accurate or accurate in all cases, given the recurrent existence of economic bubbles (when some assets are dramatically overpriced) and the fact that value investors (who focus on underpriced assets) have tended to outperform the broader market over long periods. Tillinghast also asserts that even staunch EMH proponents will admit weaknesses to the theory when assets are significantly over- or under-priced, such as double or half their value according to fundamental analysis.

In a 2012 book, investor Jack Schwager argues the EMH is "right for the wrong reasons". He agrees it is "very difficult" to consistently beat average market returns, but contends it's not due to how information is distributed more or less instantly to all market participants. Information may be distributed more or less instantly, but Schwager proposes information may not be interpreted or applied in the same way by different people and skill may play a factor in how information is used. Schwager argues markets are difficult to beat because of the unpredictable and sometimes irrational behavior of humans who buy and sell assets in the stock market. Schwager also cites several instances of mispricing that he contends are impossible according to a strict or strong interpretation of the EMH.

Late 2000s financial crisis
The financial crisis of 2007–08 led to renewed scrutiny and criticism of the hypothesis. Market strategist Jeremy Grantham said the EMH was responsible for the current financial crisis, claiming that belief in the hypothesis caused financial leaders to have a "chronic underestimation of the dangers of asset bubbles breaking". Financial journalist Roger Lowenstein said "The upside of the current Great Recession is that it could drive a stake through the heart of the academic nostrum known as the efficient-market hypothesis." Former Federal Reserve chairman Paul Volcker said "It should be clear that among the causes of the recent financial crisis was an unjustified faith in rational expectations, market efficiencies, and the techniques of modern finance." One financial analyst said "By 2007–2009, you had to be a fanatic to believe in the literal truth of the EMH."

At the International Organization of Securities Commissions annual conference, held in June 2009, the hypothesis took center stage. Martin Wolf, the chief economics commentator for the Financial Times, dismissed the hypothesis as being a useless way to examine how markets function in reality. Economist Paul McCulley said the hypothesis had not failed, but was "seriously flawed" in its neglect of human nature.

The financial crisis led economics scholar Richard Posner to back away from the hypothesis. Posner accused some of his Chicago School colleagues of being "asleep at the switch", saying that "the movement to deregulate the financial industry went too far by exaggerating the resilience—the self healing powers—of laissez-faire capitalism." Others, such as economist and Nobel laurete Eugene Fama, said that the hypothesis held up well during the crisis: "Stock prices typically decline prior to a recession and in a state of recession. This was a particularly severe recession. Prices started to decline in advance of when people recognized that it was a recession and then continued to decline. That was exactly what you would expect if markets are efficient." Despite this, Fama said that "poorly informed investors could theoretically lead the market astray" and that stock prices could become "somewhat irrational" as a result.

Efficient markets applied in securities class action litigation
The theory of efficient markets has been practically applied in the field of Securities Class Action Litigation. Efficient market theory, in conjunction with "fraud-on-the-market theory", has been used in Securities Class Action Litigation to both justify and as mechanism for the calculation of damages. In the Supreme Court Case, Halliburton v. Erica P. John Fund, U.S. Supreme Court, No. 13-317, the use of efficient market theory in supporting securities class action litigation was affirmed. Supreme Court Justice Roberts wrote that "the court's ruling was consistent with the ruling in 'Basic' because it allows 'direct evidence when such evidence is available' instead of relying exclusively on the efficient markets theory."

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Efficient-market hypothesis


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Martti Ahtisaari

Martti Oiva Kalevi Ahtisaari (23 June 1937 – 16 October 2023) was a Finnish politician, the tenth president of Finland, from 1994 to 2000, a Nobel Peace Prize laureate, and a United Nations diplomat and mediator noted for his international peace work.

Ahtisaari was a United Nations special envoy for Kosovo, charged with organizing the Kosovo status process negotiations. These negotiations aimed to resolve a long-running dispute in Kosovo, which later declared its independence from Serbia in 2008. In October 2008, he was awarded the Nobel Peace Prize "for his important efforts, on several continents and over more than three decades, to resolve international conflicts". The Nobel statement said that Ahtisaari had played a prominent role in resolving serious and long-lasting conflicts, including ones in Namibia, Aceh (Indonesia), Kosovo and Serbia, and Iraq.

Youth and early career
Martti Ahtisaari was born in Viipuri, Finland (now Vyborg, Russia) on 23 June 1937. His father, Oiva Ahtisaari, whose grandfather Julius Marenius Adolfsen had emigrated with his parents to Kotka, Finland in 1872 from Tistedalen in Southern Norway, took Finnish citizenship in 1929 and Finnicized his surname from Adolfsen in 1935. Oiva was working as a NCO in the supply troops in Vyborg when Martti was born.

The Continuation War (World War II) took Oiva Ahtisaari to the front as a non-commissioned officer army mechanic, while Martti's mother, Tyyne, moved to Kuopio with her son to escape immediate danger from the war in 1940. Kuopio was where Ahtisaari spent most of his childhood, eventually attending Kuopion Lyseo high school.

In 1952, Martti Ahtisaari moved to Oulu with his family. There he continued his education in high school, graduating in 1956. He also joined the local YMCA. After completing his military service (Ahtisaari held the rank of captain in the Finnish Army Reserve), he began to study at Oulu teachers' college, attending the two-year course which enabled him to qualify as a primary-school teacher in 1959.

In the summer of 1960, Ahtisaari signed the contract for the position of director of the Swedish Agency for International Development physical education boarding school in Karachi, Pakistan, after interviewing in Sweden and hearing about the offer announced by the YMCA in April of that year. There, he also trained as a teacher.

He returned to Finland in 1963 and began his studies in the Helsinki School of Economics and soon became the Executive Director of the Helsinki International Student Club and Student International Aid, where he made friends with Namibian Nickey Iyambo. He also joined the international students' organisation AIESEC. In 1965, he joined the Ministry for Foreign Affairs in its Bureau for International Development Aid, to set up the International Development Assistance Office together with Jaakko Iloniemi, which was a pioneering office, as the Finnish presence in international cooperation in the Third World was non-existent. Ahtisaari remained in that office until 1972, where he served from 1971 as assistant to the director, a position he combined with his presence on the Government's Advisory Committee for Trade and Industry Affairs of Developing Countries.

In the Namibian independence transition
Ahtisaari began his diplomatic career in 1973 when he became Finland's Ambassador to Tanzania, Zambia, Somalia and Mozambique, an office he held until 1977. This new mission allowed him to get closer to East African affairs, monitoring from Dar es Salaam the independence process of Namibia and maintaining close contacts with South West Africa People's Organisation (SWAPO). In 1977 he was recalled by the United Nations to succeed Seán MacBride as United Nations Commissioner for Namibia, a post he held until 1981, and as representative of Secretary-General Kurt Waldheim from 1978.

Following the death of a later UN Commissioner for Namibia, Bernt Carlsson, on Pan Am Flight 103 on 21 December 1988 – on the eve of the signing of the Tripartite Accord at UN Headquarters – Ahtisaari was sent to Namibia in April 1989 as the UN Special Representative to head the United Nations Transition Assistance Group (UNTAG). Because of the illegal incursion of SWAPO troops from Angola, the South African appointed Administrator-General (AG), Louis Pienaar, sought Ahtisaari's agreement to the deployment of SADF troops to stabilize the situation. Ahtisaari took advice from British prime minister Margaret Thatcher, who was visiting the region at the time, and approved the SADF deployment. A period of intense fighting ensued when at least 375 SWAPO insurgents were killed. In July 1989, Glenys Kinnock and Tessa Blackstone of the British Council of Churches visited Namibia and reported: "There is a widespread feeling that too many concessions were made to South African personnel and preferences and that Martti Ahtisaari was not forceful enough in his dealings with the South Africans."

Perhaps because of his reluctance to authorise this SADF deployment, Ahtisaari was alleged to have been targeted by the South African Civil Cooperation Bureau (CCB). According to a hearing in September 2000 of the South African Truth and Reconciliation Commission, two CCB operatives (Kobus le Roux and Ferdinand Barnard) were tasked not to kill Ahtisaari, but to give him "a good hiding". To carry out the assault, Barnard had planned to use the grip handle of a metal saw as a knuckleduster. In the event, Ahtisaari did not attend the meeting at the Keetmanshoop Hotel, where Le Roux and Barnard lay in wait for him, and thus Ahtisaari escaped injury.

After the independence elections of 1989, Ahtisaari and his wife were made honorary Namibian citizens in 1992. South Africa gave him the O R Tambo award for "his outstanding achievement as a diplomat and commitment to the cause of freedom in Africa and peace in the world".

Ahtisaari served as UN undersecretary-general for administration and management from 1987 to 1991 causing mixed feelings inside the organisation during an internal investigation of massive fraud. When Ahtisaari revealed in 1990 that he had secretly lengthened the grace period allowing UN officials to return misappropriated taxpayer money from the original three months to three years, the investigators were furious. The 340 officials found guilty of fraud were able to return money even after their crime had been proven. The harshest punishment was the firing of twenty corrupt officials.

Other roles
On 31 July 1991, he was appointed Secretary of State at the Ministry for Foreign Affairs of Finland in the Esko Aho's government. After the Gulf War, Ahtisaari headed a team tasked with reporting to the UN on changes in the situation and humanitarian needs. The report did not meet these expectations and was believed to have eroded American support for Ahtisaari's candidacy for the UN Secretary-General.

Between 1992 and 1993, Ahtisaari chaired the UN Conference on Yugoslavia's Working Group on Bosnia and Herzegovina and became the special assistant to Cyrus Vance, the Special Envoy of the Secretary-General of the United Nations for Croatia.

President of Finland (1994–2000)

Finland's ongoing recession caused established political figures to lose public support, and the presidential elections were now direct instead of being conducted through an electoral college. The Social Democratic Party of Finland's candidate to succeed Mauno Koivisto as President of Finland was decided in a primary between Ahtisaari and former Prime Minister and diplomat Kalevi Sorsa. Ahtisaari led in the polls against Sorsa, who was already a popular and experienced politician and won the primaries on 16 May 1993 with 61% of the votes.

After the primaries, Ahtisaari returned to his work in Geneva, and did not start his presidential campaign until the end of October. Ahtisaari narrowly won over his second round opponent, Elisabeth Rehn of the Swedish People's Party. During the campaign, there were rumours spread by some political opponents of Ahtisaari that he had a drinking problem or that he had knowingly accepted a double salary from the Finnish Foreign Ministry and from the United Nations while trying to negotiate an end to the Bosnian War. Ahtisaari denied both allegations and no firm proof of them has emerged. During the three-week campaign between the two rounds of presidential elections, Ahtisaari was praised by his supporters for being more compassionate towards the many unemployed Finns than Rehn, who as Defence Minister had to officially support the Aho government's strict economic policies. A minor controversy arose during a town hall-style presidential debate in Lappeenranta, southeastern Finland when an apparently born-again Christian woman in the audience asked Rehn what her relationship with Jesus was. Rehn replied that she had personally no proof that Jesus had been a historical person. Ahtisaari ducked a precise answer by stating that he trusted the Lutheran confession even on this issue. He was sworn in on 1 March 1994.

His term as president began with a schism within the Centre Party government led by prime minister Esko Aho, who did not approve of Ahtisaari's being actively involved in foreign policy. There was also some controversy over Ahtisaari's speaking out on domestic issues such as unemployment. He travelled extensively in Finland and abroad, and was nicknamed "Matka-Mara" ("Travel-Mara", Mara being a common diminutive form of Martti). His monthly travels throughout the country and his meetings with ordinary citizens (the so-called maakuntamatkat or "provincial trips") nonetheless greatly enhanced his political popularity. Ahtisaari kept his campaign promise to visit one Finnish historical province every month during his presidency. He also donated some thousands of Finnish marks per month to the unemployed people's organisations, and a few thousand Finnish marks to the Christian social organisation of the late lay preacher and social worker Veikko Hursti.

Ahtisaari favoured pluralism and religious tolerance publicly. Privately, he and his wife practised their Christian faith. Contrary to some of his predecessors and his successor as the Finnish President, Ahtisaari ended all of his New Year's speeches by wishing the Finnish people God's blessing.

In January 1998 Ahtisaari was criticized by some NGOs, politicians and notable cultural figures because he awarded Commander of the Order of the Lion of Finland to the Forest Minister of Indonesia and to the main owner of the Indonesian RGM Company, a parent company of the April Company. The April Company was criticized by non-governmental organisations for destroying rain forests, and Indonesia itself was criticized heavily for human rights violations, especially in East Timor. Ahtisaari's party chairman Erkki Tuomioja said that giving medals was questionable since he feared the act may tarnish the public image of Finnish human rights policy. Students of the arts had demonstrations in Helsinki against the decision to give medals.

President Ahtisaari publicly supported Finland's entry into the European Union, and in a 1994 referendum, 57 percent of Finnish voters were in favour of EU membership. He later stated that if Finland had not voted to join the EU he would have resigned. The promotion of a European collective security system and Nordic cooperation, as well as a security policy without membership of NATO, were central to Ahtisaari's foreign policy.

During Ahtisaari's term as president, Boris Yeltsin and Bill Clinton met in Helsinki. He also negotiated alongside Viktor Chernomyrdin with Slobodan Milošević to end the fighting in the Yugoslav province of Kosovo in 1999.

Ahtisaari's lack of restrained involvement in public affairs and his pronouncements on domestic and economic policy provoked reservations both in Parliament itself and in the Social Democratic Party of Finland, and led Ahtisaari not to stand for re-election in 2000, which was announced in April 1999, and also alleged that two members of the SDP also ran as candidates. Ahtisaari was the last "strong president", before the 2000 constitution reduced the president's powers. He was succeeded by Tarja Halonen on 1 March 2000.

Post-presidential life
In Finnish politics, Ahtisaari long stressed how important it is for Finland to join NATO. Ahtisaari argued that Finland should be a full member of NATO and the EU in order "to shrug off once and for all the burden of Finlandization". He believed politicians should file application and make Finland a member. He said that the way Finnish politicians avoided expressing their opinions was disturbing. He also noted that the so-called "NATO option" (acquiring membership if Finland were to be threatened) was an illusion, making an analogy to trying to obtain fire insurance when the fire has already started. Finland joined NATO on 4 April 2023, while Ahtisaari was still alive.

After leaving office, Ahtisaari held positions in various international organisations. In 2000, he became Chairman of the Brussels-based International Crisis Group, an NGO to which he committed $100,000 in government funding in 1994 one month after becoming elected President of Finland. He remained Chairman Emeritus.

Ahtisaari also founded the independent Crisis Management Initiative (CMI) with the goal of developing and sustaining peace in troubled areas. On 1 December 2000, Ahtisaari was awarded the J. William Fulbright Prize for International Understanding by the Fulbright Association in recognition of his work as a peacemaker in some of the world's most troubled areas. In May 2017 Ahtisaari suggested as new CMI leader Alexander Stubb a Finnish politician representing Finnish conservatives i.e. the National Coalition Party.

In 2000–01, Ahtisaari and Cyril Ramaphosa inspected IRA weapons dumps for the Independent International Commission on Decommissioning, as part of the Northern Ireland peace process.

In 2003 Ahtisaari defended George W. Bush's attack to Iraq, describing it as humanitarian intervention, which incited criticism from professor of history Juha Sihvola.

In November 2005, UN Secretary-General Kofi Annan appointed Ahtisaari as Special Envoy for the Kosovo status process which was to determine whether Kosovo, having been administered by the United Nations since 1999, should become independent or remain a province of Serbia. In early 2006, Ahtisaari opened the UN Office of the Special Envoy for Kosovo (UNOSEK) in Vienna, Austria, from where he conducted the Kosovo status negotiations. Those opposed to Ahtisaari's settlement proposal, which involved an internationally monitored independence for Kosovo, sought to discredit him. Allegations made by Balkan media sources of corruption and improper conduct by Ahtisaari were described by US State Department spokesman Tom Casey as "spurious", adding that Ahtisaari's plan is the "best solution possible" and has the "full endorsement of the United States". The New York Times suggested that this criticism of Ahtisaari on the part of the Serbs had led to the "bogging down" of the Kosovo status talks. In November 2008, Serbian media reported Pierre Mirel, director of the EU enlargement commission's western Balkans division as saying: "The EU has accepted that the deployment of EULEX has to be approved by the United Nations Security Council, and that the mission has to be neutral and will not be related to the Ahtisaari plan," Mirel said, following his meeting with Serbia's vice-president Bozidar Djelic.

In July 2007, however, when the EU, Russia and the United States agreed to find a new format for the talks, Ahtisaari announced that he regarded his mission as over. Since neither the UN nor the troika had asked him to continue mediations in the face of Russia's persistent refusal to support independence for Kosovo, he said he would nonetheless be willing to take on "a role as consultant", if requested. After a period of uncertainty and mounting tension, Kosovo unilaterally declared its independence from Serbia in February 2008.

In his work, he emphasised the importance of the United States in the peace process, stating that "There can be no peace without America."

Ahtisaari was chairman of the Interpeace Governing Council from 2000 to 2009. Beginning in 2009, Ahtisaari was Chairman Emeritus and a Special Advisor.

Ahtisaari was board director of the ImagineNations Group.

That same year he received the 2007 UNESCO Félix Houphouët-Boigny Peace Prize, for "his lifetime contribution to world peace".

In September 2009 Ahtisaari joined The Elders, a group of independent global leaders who work together on peace and human rights issues. He travelled to the Korean Peninsula with fellow Elders Gro Harlem Brundtland, Jimmy Carter and Mary Robinson in April 2011, and to South Sudan with Robinson and Archbishop Desmond Tutu in July 2012.

He was also a member of the board of the European Council on Foreign Relations.

Syria conflict
In August 2012, Ahtisaari opined on the sectarian violence in Syria and was mentioned as a possible replacement as Joint Envoy there to succeed former Secretary-General Kofi Annan. However, Ahtisaari then told the Finnish state broadcaster YLE that "he wished the mission would fall on someone else" which it ultimately did in the person of Lakhdar Brahimi, a former Algerian foreign minister and longtime U.N. diplomat.

In late 2015, Martti Ahtisaari reiterated charges he already had made in an interview with German broadcaster Deutsche Welle in early 2013 against members of the UN security council on the obstruction of a political solution to the escalating conflict in Syria. Ahtisaari said in an interview in September 2015 that he held talks about Syria with envoys from the five permanent members of the UN security council in February 2012. According to Ahtisaari, Vitaly Churkin, Russian ambassador to the United Nations, laid out three points during a meeting with him, which included not arming the Syrian opposition, commencing talks between Syrian president Assad and the opposition and finding "an elegant way for Assad to step aside". But the US, Britain and France subsequently ignored the proposal. Ahtisaari said in the interview: "Nothing happened because I think all these, and many others, were convinced that Assad would be thrown out of office in a few weeks so there was no need to do anything."

Personal life, health and death
In 1968, he married Eeva Irmeli Hyvärinen, who was studying history at the University of Helsinki and whom he met as a child at the Lyceum in Kuopio. They had one son, Marko Ahtisaari, who was born in 1969.

On 24 March 2020, amid the large-scale outbreak of COVID-19, it was announced that Ahtisaari had tested positive for the disease. His spouse, Eeva Ahtisaari, was diagnosed with the same virus on 21 March. Eeva Ahtisaari had attended the International Women's Day concert on 8 March at the Helsinki Music Centre while infected. On 14 April 2020 it was announced that Martti and Eeva Ahtisaari were recovering from the coronavirus infection.

On 2 September 2021, it was announced that Ahtisaari had Alzheimer's disease and had retired from public life.

Ahtisaari died from complications of Alzheimer's disease in Helsinki, on 16 October 2023, at age 86. His state funeral was held on 10 November 2023 in Helsinki Cathedral at 1 p.m., after which he was buried at the Hietaniemi Cemetery in Helsinki.

Nobel Peace Prize
On 10 October 2008, Ahtisaari was announced as that year's recipient of the Nobel Peace Prize. Ahtisaari received the prize on 10 December 2008 at Oslo City Hall in Norway. Ahtisaari twice worked to find a solution in Kosovo – first in 1999 and again between 2005 and 2007. The committee said he also worked with others this year to find a peaceful solution to the problems in Iraq. According to the committee, Ahtisaari and his group, Crisis Management Initiative (CMI), also contributed to resolving other conflicts in Northern Ireland, Central Asia, and the Horn of Africa. Ahtisaari invited Prime Minister Matti Vanhanen, Foreign Affairs Minister Alexander Stubb and others to his Nobel event, but not President Halonen.

According to the memoir of the former secretary of the Norwegian Nobel Committee, Geir Lundestad, former Foreign Minister and UN ambassador Keijo Korhonen, who was strongly against awarding the 2008 Nobel Peace Prize to Ahtisaari, wrote a letter to the committee which negatively portrayed Ahtisaari as a person and his merits in international conflict zones.

National honours

 * 🇫🇮 Finland:
 * FIN Order of the White Rose Grand Cross BAR.svg Grand Cross with Collar of the Order of the White Rose of Finland (1999)
 * JPN Hokan-sho blank BAR.svg Grand Cross of the Order of the Cross of Liberty
 * FIN Order of the Lion of Finland 1Class BAR.svg Grand Cross of the Order of the Lion of Finland
 * FIN Saint Henry Cross BAR.svg Saint Henry Cross
 * FIN Order of the Holy Lamb BAR.svg Grand Cross of the Order of the Holy Lamb

Foreign honours

 * 🇦🇱 Albania:
 * ALB National Flag Order.png National Flag Decoration (12 September 2016)
 * 🇦🇺 Australia:
 * AUS Order of Australia (civil) BAR.svg Honorary Officer of the Order of Australia (2002)
 * 🇦🇷 Argentina:
 * ARG Order of the Liberator San Martin - Grand Cross BAR.svg Grand Cross with Collar of the Order of the Liberator General San Martín (3 March 1997)
 * 🇧🇪 Belgium:
 * BEL - Order of Leopold - Grand Cordon bar.svg Grand Cordon of the Order of Leopold
 * 🇧🇷 Brazil:
 * BRA - Order of the Southern Cross - Grand Cross BAR.svg Grand Cross of the Order of the Southern Cross
 * 🇨🇱 Chile:
 * CHL Order of Merit of Chile - Grand Cross BAR.svg Collar of the Order of Merit
 * 🇩🇰 Denmark:
 * Order of the Elephant Ribbon bar.svg Knight of the Order of the Elephant (1994)
 * Order of the Dannebrog R.svg Knight of the Order of the Dannebrog
 * 🇪🇪 Estonia:
 * EST Order of the Cross of Terra Mariana - 1st Class BAR.svg Collar of the Order of the Cross of Terra Mariana
 * 🇫🇷 France:
 * Legion Honneur GC ribbon.svg Grand Cross of the Order of Legion of Honour
 * 🇩🇪 Germany:
 * GER Bundesverdienstkreuz 9 Sond des Grosskreuzes.svg Grand Cross Special Class of the Order of Merit of the Federal Republic of Germany
 * 🇬🇷 Greece:
 * GRE Order Redeemer 1Class.svg Grand Cross of the Order of the Redeemer
 * 🇭🇺 Hungary:
 * HUN Order of Merit of the Hungarian Rep (civil) 1class BAR.svg Grand Cross of the Order of Merit of the Republic of Hungary
 * 🇮🇸 Iceland:
 * ISL Icelandic Order of the Falcon - Grand Cross BAR.png Collar with Grand Cross of the Order of the Falcon (26 September 1995)
 * 🇮🇩 Indonesia:
 * Bintang Republik Indonesia Utama Ribbon1.gif Third Class of the Star of the Republic of Indonesia
 * 🇮🇹 Italy:
 * Cordone di gran Croce di Gran Cordone OMRI BAR.svg Knight Grand Cross with Collar of the Order of Merit of the Italian Republic (1997)
 * 🇰🇼 Kuwait:
 * Order of Mubarak the Great (Kuwait) - ribbon bar.gif Grand Cordon of the Order of Mubarak the Great
 * 🇱🇻 Latvia:
 * LVA Order of the Three Stars - Commander BAR.png Commander Grand Cross of the Order of the Three Stars:
 * 🇱🇹 Lithuania
 * LTU Order of Vytautas the Great - Grand Cross BAR.svg Grand Cross of the Order of Vytautas the Great (1996)
 * 🇲🇾 Malaysia:
 * MY Darjah Utama Seri Mahkota Negara (Crown of the Realm) - DMN.svg Honorary Recipient of the Most Exalted Order of the Crown of the Realm (1995)
 * 🇲🇽 Mexico:
 * MEX Order of the Aztec Eagle 1Class BAR.png Collar of the Order of the Aztec Eagle (1999)
 * 🇳🇱 Netherlands:
 * Order of the Netherlands Lion ribbon - Knight Grand Cross.svg Knight Grand Cross of the Order of the Netherlands Lion
 * 🇳🇴 Norway:
 * St Olavs Orden storkors stripe.svg Grand Cross with Collar of the Order of St. Olav (1994)
 * 🇵🇱 Poland:
 * POL Order Orła Białego BAR.svg Knight of the Order of the White Eagle (1997)
 * 🇷🇴 Romania:
 * Order of the Star of Romania - Ribbon bar.svg Grand Cross of the Order of the Star of Romania
 * 🇿🇦 South Africa:
 * Order of the Companions of O.R. Tambo (ribbon bar).gif Supreme Companion of the Order of the Companions of O. R. Tambo (16 June 2004)
 * Ord.GoodHope-ribbon.gif Grand Cross of the Order of Good Hope (1997)
 * 🇪🇸 Spain:
 * Order of Isabella the Catholic - Sash of Collar.svg Knight of the Collar of the Order of Isabella the Catholic
 * 🇸🇪 Sweden:
 * Order of the Seraphim - Ribbon bar.svg Knight with Collar (1996) of the Royal Order of the Seraphim (1994)
 * 🇹🇷 Turkey:
 * Order of the State of Republic of Turkey.png First Class of the Order of the State of the Republic of Turkey (1999)
 * 🇺🇦 Ukraine:
 * Order of Prince Yaroslav the Wise 1st 2nd and 3rd Class of Ukraine.png First Class of the Order of Yaroslav the Wise
 * 🇦🇪 United Arab Emirates:
 * Order of the Union. Sash ribbon or First Class.gif First Class of the Order of Federation
 * 🇬🇧 United Kingdom:
 * Order of the Bath UK ribbon.svg Honorary Knight Grand Cross of the Order of the Bath (1995)

Awards

 * 1995: Zamenhof Prize for International Understanding, of the World Esperanto Association
 * 1998: Honorary doctorate from Helsinki University of Technology, and from National University of Kyiv-Mohyla Academy
 * 2000: J. William Fulbright Prize for International Understanding
 * 2000: Freedom medal
 * 2000: 🇩🇪 Germany: Hessian Peace Prize
 * 2004: OR Tambo Award
 * 2006: Gold Medal of The American-Scandinavian Foundation
 * 2007: 🇩🇪 Germany: Manfred Wörner Medal of the German Ministry of Defense
 * 2007: Honorary degree, University of St. Gallen, Switzerland
 * 2008: Delta Prize for Global Understanding
 * 2008: Félix Houphouët-Boigny Peace Prize
 * 2008: Nobel Peace Prize
 * 2008: 🇳🇱 Netherlands: Geuzenpenning
 * 2011: Honorary degree, University of Calgary, Canada

title: Martti Ahtisaari


text:
Geopotential height

Geopotential height or geopotential altitude is a vertical coordinate referenced to Earth's mean sea level (assumed zero geopotential) that represents the work involved in lifting one unit of mass over one unit of length through a hypothetical space in which the acceleration of gravity is assumed constant. In SI units, a geopotential height difference of one meter implies the vertical transport of a parcel of one kilogram; adopting the standard gravity value (9.80665 m/s2), it corresponds to a constant work or potential energy difference of 9.80665 joules.

Geopotential height differs from geometric height (as given by a tape measure) because Earth's gravity is not constant, varying markedly with altitude and latitude; thus, a 1-m geopotential height difference implies a different vertical distance in physical space: "the unit-mass must be lifted higher at the equator than at the pole, if the same amount of work is to be performed". It is a useful concept in meteorology, climatology, and oceanography; it also remains a historical convention in aeronautics as the altitude used for calibration of aircraft barometric altimeters.

Definition
Geopotential is the gravitational potential energy per unit mass at elevation $$Z$$:
 * $$\Phi(Z) = \int_0^Z\ g(\phi,Z)\,dZ$$

where $$g(\phi,Z)$$ is the acceleration due to gravity, $$\phi$$ is latitude, and $$Z$$ is the geometric elevation.

Geopotential height may be obtained from normalizing geopotential by the acceleration of gravity:
 * $${H} = \frac{\Phi}{g_{0}}\ = \frac{1}{g_{0}}\int_0^Z\ g(\phi,Z)\,dZ$$

where $$g_0$$ = 9.80665 m/s2, the standard gravity at mean sea level. Expressed in differential form,
 * $${g_0}\ {dH} = {g}\ {dZ}$$

Role in planetary fluids
Geopotential height plays an important role in atmospheric and oceanographic studies. The differential form above may be substituted into the hydrostatic equation and ideal gas law in order to relate pressure to ambient temperature and geopotential height for measurement by barometric altimeters regardless of latitude or geometric elevation:
 * $${dP} = {-g}\ {\rho}\ {dZ} = {-g_0}\ {\rho}\ {dH} = \frac{-g_0\ P}{R\ T}\ {dH}$$
 * $$\frac{dP}{P} = -\frac{g_0}{R\ T}\ {dH}$$

where $$P$$ and $$T$$ are ambient pressure and temperature, respectively, as functions of geopotential height, and $$R$$ is the specific gas constant. For the subsequent definite integral, the simplification obtained by assuming a constant value of gravitational acceleration is the sole reason for defining the geopotential altitude.

Usage
Geophysical sciences such as meteorology often prefer to express the horizontal pressure gradient force as the gradient of geopotential along a constant-pressure surface, because then it has the properties of a conservative force. For example, the primitive equations that weather forecast models solve use hydrostatic pressure as a vertical coordinate, and express the slopes of those pressure surfaces in terms of geopotential height.

A plot of geopotential height for a single pressure level in the atmosphere shows the troughs and ridges (highs and lows) which are typically seen on upper air charts. The geopotential thickness between pressure levels – difference of the 850 hPa and 1000 hPa geopotential heights for example – is proportional to mean virtual temperature in that layer. Geopotential height contours can be used to calculate the geostrophic wind, which is faster where the contours are more closely spaced and tangential to the geopotential height contours.

The National Weather Service defines geopotential height as:

title: Geopotential height


text:
Aksel Airo

Aksel Fredrik Airo (14 February 1898 – 9 May 1985) was a Finnish lieutenant general and main strategic planner during the Winter War and the Continuation War. He was the virtual second-in-command of the Finnish army under Field Marshal C.G.E. Mannerheim.

He was born in Turku. As a young man he became a supporter of Finnish independence. His father changed the original, Swedish, family name Johansson to Airo (lit. "oar").

During the Civil War in Finland (1918), Airo served in the artillery on the White side, taking part in battles near Viipuri. At the end of the war he was a lieutenant. Afterwards he was trained as an officer in Lappeenranta artillery school and was sponsored to the French military academy, École militaire in St.-Cyr in 1920. In 1921 he was accepted into École Supérieure de Guerre, the French officer training academy, from which he graduated as a captain in 1923, at the age of 27. Mannerheim invited him to join Finland's Defense Council as a secretary.

Airo rose swiftly in rank, mainly because newly independent Finland needed suitable officers for the fledgling army. He had, however, some professional challenges because he was neither a Germany-trained Jaeger officer, nor one of the officers trained in the Tsar's army during Russian rule. Still, by 1930 he had become a colonel.

In the beginning of the Winter War, Mannerheim appointed Airo as Quartermaster-General, and he was promoted to major general, and two years later to lieutenant general. On November 18, 1944, Marshal Mannerheim made him a Knight of the Mannerheim Cross in Order of the Cross of Liberty.

Airo was in the Mikkeli headquarters during the war and rarely went to the field. He was responsible for operational planning and the presentation of operations, or, as he allegedly said, "The Marshal leads the war, but I lead the battles". They had many differences in opinion but still managed to work well together.

After the Continuation War, the now Communist-dominated Valpo (the Finnish State Police) arrested him for his alleged involvement in the so-called Weapons Cache Case. He was imprisoned for nearly three years, 1945 to 1948 without being sentenced, until president Juho Kusti Paasikivi released him. He said almost nothing about the affair afterwards and earned the moniker "the silent general". The President relieved him of his duties with special permission to wear a military uniform.

In his later life Airo was a member of the parliament for the National Coalition Party and a presidential elector. Unlike many of his contemporaries, he never wrote memoirs about his war experiences. In 1982 President Mauno Koivisto awarded Airo with the Grand Cross of the Finnish Order of the White Rose with swords, which was a very rare honour in Finland. He died in 1985 at his home farm in Heinola.

title: Aksel Airo


text:
Sensible heat

Sensible heat is heat exchanged by a body or thermodynamic system in which the exchange of heat changes the temperature of the body or system, and some macroscopic variables of the body or system, but leaves unchanged certain other macroscopic variables of the body or system, such as volume or pressure.

Usage
The term is used in contrast to a latent heat, which is the amount of heat exchanged that is hidden, meaning it occurs without change of temperature. For example, during a phase change such as the melting of ice, the temperature of the system containing the ice and the liquid is constant until all ice has melted. The terms latent and sensible are correlative.

The sensible heat of a thermodynamic process may be calculated as the product of the body's mass (m) with its specific heat capacity (c) and the change in temperature ($$\Delta T$$):
 * $$ Q_{sensible} = m c \Delta T \, .$$

Sensible heat and latent heat are not special forms of energy. Rather, they describe exchanges of heat under conditions specified in terms of their effect on a material or a thermodynamic system.

In the writings of the early scientists who provided the foundations of thermodynamics, sensible heat had a clear meaning in calorimetry. James Prescott Joule characterized it in 1847 as an energy that was indicated by the thermometer.

Both sensible and latent heats are observed in many processes while transporting energy in nature. Latent heat is associated with changes of state, measured at constant temperature, especially the phase changes of atmospheric water vapor, mostly vaporization and condensation, whereas sensible heat directly affects the temperature of the atmosphere.

In meteorology, the term 'sensible heat flux' means the conductive heat flux from the Earth's surface to the atmosphere. It is an important component of Earth's surface energy budget. Sensible heat flux is commonly measured with the eddy covariance method.

title: Sensible heat


text:
Kyösti Kallio

Kyösti Kallio (10 April 1873 – 19 December 1940) was a Finnish politician who served as the fourth president of Finland from 1937 to 1940. His presidency included leading the country through the Winter War; while he relinquished the post of commander-in-chief to Carl Gustaf Emil Mannerheim, he played a role as a spiritual leader. After the war, he became both the first President of Finland to resign and the only one to die in office, dying of a heart attack while returning home after submitting his resignation.

Kallio was the only president of Finland who did not have an academic or similar degree. He was a prominent leader of the Agrarian League party, and served as Prime Minister four times and Speaker of the Parliament six times. During his political career, he also served as a five-time Minister of Agriculture for most of the period between 1917 and 1922, including in the Independence Senate and the Civil War-era White cabinet, led a 1922 land reform to aid tenant farmers in acquiring their own land, and was a candidate in the 1931 presidential election before defeating incumbent president Pehr Evind Svinhufvud in the subsequent elections of 1937.

Early life
Kyösti Kallio, originally Gustaf Kalliokangas ( forename's, surname's ), was born in Ylivieska, Grand Duchy of Finland, which was an autonomous region of the Russian Empire at the time. His father Mikko Kalliokangas was a farmer and prominent local politician. Young Kyösti's life also included his father's unmarried and childless cousin, Anttuuna Kangas, or aunt Anttuuna, who arranged for the boy to go to Raahe's junior high school in 1886. After that, he was educated in Oulu where he became acquainted with Santeri Alkio, author and future ideologue of the Agrarian League.

Start of career
Kallio entered politics during the first Russification campaign of Finland as a member of the Young Finnish Party. He served in the Diet of Finland from 1904 to 1906 as a member of the Estate of the Peasantry. He joined the newly founded Agrarian League in 1906 and became one of its most prominent leaders.

Finland gains independence
After the February Revolution of 1917 dethroned Tsar Nicholas II, the Russian provisional government tasked Vice Admiral Adrian Nepenin with overseeing the change of government in Finland. Nepenin started by inviting a handful of Finnish politicians to discuss the situation on March 17. Kallio represented the Agrarian League; and when the Finnish politicians the next day sent a delegation to Saint Petersburg to negotiate a cessation to the Russification campaign, Kallio was again a member. The delegation was successful, and Finland was permitted to assemble a fully parliamentary Senate. Kallio came to serve as Agrarian minister in the Senate of Oskari Tokoi, which took office March 26. Most of his time was spent trying to mediate the agrarian strikes and finding foodstuffs for the country, while the First World War raised the prices in Europe.

After the Tsar had been dethroned, the Finnish Parliament had to decide whether the highest authority in the country had passed on to the Russian Provisional Government, the Finnish Parliament, or the Finnish Senate. The question led to serious strife between the right-wing and left-wing elements of the Parliament. Kallio initially supported the socialists in demanding that power transfer to the Parliament, but disapproved of their cooperation with Russian Bolsheviks and Mensheviks; and Kallio ultimately voted against the bill they had drafted. Nonetheless, the socialist proposal passed, which the Russian Provisional Government saw as an affront to their power; and Alexander Kerensky consequently dissolved the Finnish Parliament on September 8. Kallio and the Socialist senators resigned from the senate, which continued to operate under the leadership of E. N. Setälä.

After the October Revolution, the Finnish bourgeoisie were willing to compromise and give parliament the highest authority fearing Bolshevik rule would spread to Finland. Setälä's Senate resigned immediately after the question was settled. Kallio was again named Agrarian Minister in the Senate of P. E. Svinhufvud whose first priority was to declare Finland independent. On December 4 the Senate introduced a declaration of independence to the Parliament; and the next day Kallio wrote a resolution, which the Parliament passed with votes 100–88.

Civil war
During the Civil War in Finland, Kallio hid in red-dominated Helsinki, because he was at least nominally on the white side and therefore a "class enemy"; he formed a new senate (government) in Helsinki after German troops had defeated the reds in the city. Afterwards he became a moderate peace-maker and disapproved of retaliation against the reds. In his reconciliation speech in Nivala, Kallio said the following:"We have to create a Finland where there are no reds or whites, but only Finns who love their country, citizens of the Republic of Finland, who all feel like members of society and enjoy themselves here."

Formation of the republic
During the debates over the form of the new state in 1918, Kallio resigned from the senate because he supported a republic instead of constitutional monarchy. Eventually, the monarchist stand lost, and he returned to the Cabinet to become prime minister. He was a reformist who emphasized education, settlement, and land reform. His greatest achievement was "Lex Kallio" in 1922, legislation allowing the state to buy land to encourage new settlements, and to let the former tenant farmers and other landless rural people buy small farms (see, for example, Seppo Zetterberg et al., ed., "Suomen historian pikkujättiläinen").

Supported prohibition
He supported Prohibition in Finland, and was dismayed when it was repealed in 1932.

Non-violent anti-communist
Kallio was an anti-communist, suppressing the Finnish Communist Party (SKP) in 1923, but he resorted to legislative methods. When the violent right-wing Lapua Movement asked him to become their leader, he refused and was then instead subjected to their death threats.

President
Kallio was elected president with the votes of a centrist (Agrarian and Progressive) and social democratic coalition, which wanted to ensure that President Svinhufvud would not be re-elected. Kallio took the role of a parliamentarian president and avoided use of his personal power.

On the eve of the Winter War, when Marshal Mannerheim once again threatened to resign from his post as chairman of Finland's Defence Council due to a schism with the cabinet, Kallio convinced him to stay. During the war Kallio resisted the idea of giving up any territory to the Soviet Union, but was forced to agree to sign the Moscow Peace Treaty in 1940. His health began to fail – and his right arm was paralyzed – He was not active in the dealings with Germany leading to the Continuation War. On 27 August Kallio suffered a serious stroke. Prime Minister Risto Ryti took over his duties. Kallio's heart became weak while he knowingly took risks by agreeing to the formal farewell ceremonies.

Resignation and death
Kallio left a notice of resignation on 27 November 1940. He was planning to leave the capital and retire to his farm at Nivala after the farewell ceremonies on the evening of 19 December 1940; but he collapsed and died that night at the Helsinki Central Railway Station in the arms of his adjutant before a guard of honour while a band played the patriotic Finnish march Porilaisten marssi. One story tells that Kallio died in the arms of Marshal Mannerheim, but this is most likely part of the construction of Mannerheim's personal cult. In reality, Kallio died in the arms of his adjutant Aladár Paasonen and colonel A. F. Airo.

Religious views
A significant part of Kallio's personality and a motive for the social reforms which he supported and promoted was his deep Christian faith, which he had adopted already at home, and which was deepened during his marriage to Kaisa Nivala, who was also a devout Christian. Although Kallio was often too busy to go to church, he prayed often when encountering difficulties in making political decisions, and some of these prayers he recorded in his diary. He also read Christian books with his wife and often discussed them by exchanging letters. He often referred to God in his speeches, and during the Winter War he asked the Finns who were serving their country to read the Bible. When he was forced to sign the harsh Moscow Peace Treaty in March 1940, Kallio quoted freely from the Book of Zechariah, saying: "'May my hand, which is forced to sign such a paper, wither.'" His right arm was paralysed the following summer, and he was forced to switch his writing hand. In the Presidential Palace, shortly before leaving for Helsinki Central Railway Station for the last time, Kallio sang a hymn with his family.

In popular culture
Kallio was played by Ossi Ahlapuro in the 2001 television film Valtapeliä elokuussa 1940, directed by Veli-Matti Saikkonen.

Cabinets

 * Kallio I Cabinet
 * Kallio II Cabinet
 * Kallio III Cabinet
 * Kallio IV Cabinet

Awards and decorations

 * Grand Cross of the Order of the White Rose (Finland)
 * Grand Cross of the Order of the Cross of Liberty
 * Knight of the Order of the Seraphim (Sweden)
 * Order of the Polar Star (Sweden)
 * Order of the Falcon (Iceland)
 * Collar of the Order of the White Star
 * Cross of Liberty Military Leadership (Estonia)
 * Cross of Liberty Civilian Service (Estonia)
 * Order of the Cross of the Eagle
 * Order of the Estonian Red Cross
 * Order of the Three Stars (Latvia)
 * Order of Merit (Hungary)
 * Order of Polonia Restituta

title: Kyösti Kallio


text:
Latent heat

Latent heat (also known as latent energy or heat of transformation) is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process—usually a first-order phase transition, like melting or condensation.

Latent heat can be understood as hidden energy which is supplied or extracted to change the state of a substance without changing its temperature or pressure. This includes the latent heat of fusion (solid to liquid), the latent heat of vaporization (liquid to gas) and the latent heat of sublimation (solid to gas).

The term was introduced around 1762 by Scottish chemist Joseph Black. Black used the term in the context of calorimetry where a heat transfer caused a volume change in a body while its temperature was constant.

In contrast to latent heat, sensible heat is energy transferred as heat, with a resultant temperature change in a body.

Usage
The terms sensible heat and latent heat refer to energy transferred between a body and its surroundings, defined by the occurrence or non-occurrence of temperature change; they depend on the properties of the body. Sensible heat is sensed or felt in a process as a change in the body's temperature. Latent heat is energy transferred in a process without change of the body's temperature, for example, in a phase change (solid/liquid/gas).

Both sensible and latent heats are observed in many processes of transfer of energy in nature. Latent heat is associated with the change of phase of atmospheric or ocean water, vaporization, condensation, freezing or melting, whereas sensible heat is energy transferred that is evident in change of the temperature of the atmosphere or ocean, or ice, without those phase changes, though it is associated with changes of pressure and volume.

The original usage of the term, as introduced by Black, was applied to systems that were intentionally held at constant temperature. Such usage referred to latent heat of expansion and several other related latent heats. These latent heats are defined independently of the conceptual framework of thermodynamics.

When a body is heated at constant temperature by thermal radiation in a microwave field for example, it may expand by an amount described by its latent heat with respect to volume or latent heat of expansion, or increase its pressure by an amount described by its latent heat with respect to pressure.

Latent heat is energy released or absorbed by a body or a thermodynamic system during a constant-temperature process. Two common forms of latent heat are latent heat of fusion (melting) and latent heat of vaporization (boiling). These names describe the direction of energy flow when changing from one phase to the next: from solid to liquid, and liquid to gas.

In both cases the change is endothermic, meaning that the system absorbs energy. For example, when water evaporates, an input of energy is required for the water molecules to overcome the forces of attraction between them and make the transition from water to vapor.

If the vapor then condenses to a liquid on a surface, then the vapor's latent energy absorbed during evaporation is released as the liquid's sensible heat onto the surface.

The large value of the enthalpy of condensation of water vapor is the reason that steam is a far more effective heating medium than boiling water, and is more hazardous.

Meteorology
In meteorology, latent heat flux is the flux of energy from the Earth's surface to the atmosphere that is associated with evaporation or transpiration of water at the surface and subsequent condensation of water vapor in the troposphere. It is an important component of Earth's surface energy budget. Latent heat flux has been commonly measured with the Bowen ratio technique, or more recently since the mid-1900s by the eddy covariance method.

History
The English word latent comes from Latin latēns, meaning lying hidden. The term latent heat was introduced into calorimetry around 1750 by Joseph Black—commissioned by producers of Scotch whisky in search of ideal quantities of fuel and water for their distilling process—to studying system changes, such as of volume and pressure, when the thermodynamic system was held at constant temperature in a thermal bath. Black would compare the change in temperature of two identical quantities of water, heated by identical means, one of which was, say, melted from ice, whereas the other was heated from merely cold liquid state. By comparing the resulting temperatures, he could conclude that, for instance, the temperature of the sample melted from ice was 140 °F lower than the other sample, thus melting the ice absorbed 140 "degrees of heat" that could not be measured by the thermometer, yet needed to be supplied, thus it was "latent" (hidden). Black also deduced that as much latent heat as was supplied into boiling the distillate (thus giving the quantity of fuel needed) also had to be absorbed to condense it again (thus giving the cooling water required).

Later, James Prescott Joule characterised latent energy as the energy of interaction in a given configuration of particles, i.e. a form of potential energy, and the sensible heat as an energy that was indicated by the thermometer, relating the latter to thermal energy.

Specific latent heat
A specific latent heat (L) expresses the amount of energy in the form of heat (Q) required to completely effect a phase change of a unit of mass (m), usually 1 kg, of a substance as an intensive property:
 * $$L = \frac {Q}{m}.$$

Intensive properties are material characteristics and are not dependent on the size or extent of the sample. Commonly quoted and tabulated in the literature are the specific latent heat of fusion and the specific latent heat of vaporization for many substances.

From this definition, the latent heat for a given mass of a substance is calculated by
 * $$Q = {m} {L}$$

where:
 * Q is the amount of energy released or absorbed during the change of phase of the substance (in kJ or in BTU),
 * m is the mass of the substance (in kg or in lb), and
 * L is the specific latent heat for a particular substance (in kJ kg−1 or in BTU lb−1), either Lf for fusion, or Lv for vaporization.

Table of specific latent heats
The following table shows the specific latent heats and change of phase temperatures (at standard pressure) of some common fluids and gases.

Specific latent heat for condensation of water in clouds
The specific latent heat of condensation of water in the temperature range from −25 °C to 40 °C is approximated by the following empirical cubic function:
 * $$L_\text{water}(T) \approx \left(2500.8 - 2.36 T + 0.0016 T^2 - 0.00006 T^3\right)~\text{J/g},$$

where the temperature $$T$$ is taken to be the numerical value in °C.

For sublimation and deposition from and into ice, the specific latent heat is almost constant in the temperature range from −40 °C to 0 °C and can be approximated by the following empirical quadratic function:
 * $$L_\text{ice}(T) \approx \left(2834.1 - 0.29 T - 0.004 T^2\right)~\text{J/g}.$$

Variation with temperature (or pressure)
As the temperature (or pressure) rises to the critical point, the latent heat of vaporization falls to zero.

title: Latent heat