title: Hives

text: This type of urticaria is also termed rare and occurs upon contact with water. The response is not temperature-dependent and the skin appears similar to the cholinergic form of the disease. The appearance of hives is within one to 15 minutes of contact with the water and can last from 10 minutes to two hours. This kind of hives does not seem to be stimulated by histamine discharge like the other physical hives. Most researchers believe this condition is actually skin sensitivity to additives in the water, such as chlorine. Water urticaria is diagnosed by dabbing tap water and distilled water to the skin and observing the gradual response. Aquagenic urticaria is treated with capsaicin (Zostrix) administered to the chafed skin. This is the same treatment used for shingles. Antihistamines are of questionable benefit in this instance since histamine is not the causative factor.


title: Hives

text: The condition was first distinguished in 1980. People with exercise urticaria (EU) experience hives, itchiness, shortness of breath and low blood pressure five to 30 minutes after beginning exercise. These symptoms can progress to shock and even sudden death. Jogging is the most common exercise to cause EU, but it is not induced by a hot shower, fever, or with fretfulness. This differentiates EU from cholinergic urticaria.


title: Hives

text: EU sometimes occurs only when someone exercises within 30 minutes of eating particular foods, such as wheat or shellfish. For these individuals, exercising alone or eating the injuring food without exercising produces no symptoms. EU can be diagnosed by having the person exercise and then observing the symptoms. This method must be used with caution and only with the appropriate resuscitative measures at hand. EU can be differentiated from cholinergic urticaria by the hot water immersion test. In this test, the person is immersed in water at 43 °C (109.4 °F). Someone with EU will not develop hives, while a person with cholinergic urticaria will develop the characteristic small hives, especially on the neck and chest.


title: Hives

text: The immediate symptoms of this type are treated with antihistamines, epinephrine and airway support. Taking antihistamines prior to exercise may be effective. Ketotifen is acknowledged to stabilise mast cells and prevent histamine release, and has been effective in treating this hives disorder. Avoiding exercise or foods that cause the mentioned symptoms is very important. In particular circumstances, tolerance can be brought on by regular exercise, but this must be under medical supervision.


title: Hives

text: The skin lesions of urticarial disease are caused by an inflammatory reaction in the skin, causing leakage of capillaries in the dermis, and resulting in an edema which persists until the interstitial fluid is absorbed into the surrounding cells.


title: Hives

text: Hives are caused by the release of histamine and other mediators of inflammation (cytokines) from cells in the skin. This process can be the result of an allergic or nonallergic reaction, differing in the eliciting mechanism of histamine release.


title: Hives

text: Histamine and other proinflammatory substances are released from mast cells in the skin and tissues in response to the binding of allergen-bound IgE antibodies to high-affinity cell surface receptors. Basophils and other inflammatory cells are also seen to release histamine and other mediators, and are thought to play an important role, especially in chronic urticarial diseases.


title: Hives

text: Over half of all cases of chronic idiopathic hives are the result of an autoimmune trigger. Roughly 50% of people with chronic urticaria spontaneously develop autoantibodies directed at the receptor FcεRI located on skin mast cells. Chronic stimulation of this receptor leads to chronic hives. People with hives often have other autoimmune conditions, such as autoimmune thyroiditis, celiac disease, type 1 diabetes, rheumatoid arthritis, Sjögren's syndrome or systemic lupus erythematosus.


title: Hives

text: Hive-like rashes commonly accompany viral illnesses, such as the common cold. They usually appear three to five days after the cold has started, and may even appear a few days after the cold has resolved.


title: Hives

text: Mechanisms other than allergen-antibody interactions are known to cause histamine release from mast cells. Many drugs, for example morphine, can induce direct histamine release not involving any immunoglobulin molecule. Also, a diverse group of signaling substances called neuropeptides, have been found to be involved in emotionally induced hives. Dominantly inherited cutaneous and neurocutaneous porphyrias (porphyria cutanea tarda, hereditary coproporphyria, variegate porphyria and erythropoietic protoporphyria) have been associated with solar urticaria. The occurrence of drug-induced solar urticaria may be associated with porphyrias. This may be caused by IgG binding, not IgE.


title: Hives

text: This is termed scombroid food poisoning. Ingestion of free histamine released by bacterial decay in fish flesh may result in a rapid-onset, allergic-type symptom complex which includes hives. However, the hives produced by scombroid is reported not to include wheals.


title: Hives

text: Chronic idiopathic hives has been anecdotally linked to stress since the 1940s. A large body of evidence demonstrates an association between this condition and both poor emotional well-being and reduced health-related quality of life. A link between stress and this condition has also been shown. A recent study has demonstrated an association between stressful life events (e.g. bereavement, divorce, etc.) and chronic idiopathic urticaria and also an association between post-traumatic stress and chronic idiopathic hives.


title: Hives

text: Diagnosis is typically based on the appearance. The cause of chronic hives can rarely be determined. Patch testing may be useful to determine the allergy. In some cases regular extensive allergy testing over a long period of time is requested in hopes of getting new insight. No evidence shows regular allergy testing results in identification of a problem or relief for people with chronic hives. Regular allergy testing for people with chronic hives is not recommended.


title: Hives

text: Angioedema is similar to hives, but in angioedema, the swelling occurs in a lower layer of the dermis than in hives, as well as in the subcutis. This swelling can occur around the mouth, eyes, in the throat, in the abdomen, or in other locations. Hives and angioedema sometimes occur together in response to an allergen, and is a concern in severe cases, as angioedema of the throat can be fatal.


title: Hives

text: This very rare form of angioedema develops in response to contact with vibration. In vibratory angioedema, symptoms develop within two to five minutes after contact with a vibrating object and abate after about an hour. People with this disorder do not experience dermographism or pressure urticaria. Vibratory angioedema is diagnosed by holding a vibrating device such as a laboratory vortex machine against the forearm for four minutes. Speedy swelling of the whole forearm extending into the upper arm is also noted later. The principal treatment is avoidance of vibratory stimulants. Antihistamines have also been proven helpful.


title: Hives

text: The mainstay of therapy for both acute and chronic hives is education, avoiding triggers and using antihistamines.


title: Hives

text: Chronic hives can be difficult to treat and lead to significant disability. Unlike the acute form, 50–80% of people with chronic hives have no identifiable triggers. But 50% of people with chronic hives will experience remission within 1 year. Overall, treatment is geared towards symptomatic management. Individuals with chronic hives may need other medications in addition to antihistamines to control symptoms. People who experience hives with angioedema require emergency treatment as this is a life-threatening condition.


title: Hives

text: Treatment guidelines for the management of chronic hives have been published. According to the 2014 American practice parameters, treatment involves a stepwise approach. Step 1 consists of second generation, H1 receptor blocking antihistamines. Systemic glucocorticoids can also be used for episodes of severe disease but should not be used for long term due to their long list of side effects. Step 2 consists of increasing the dose of the current antihistamine, adding other antihistamines, or adding a leukotriene receptor antagonist such as montelukast. Step 3 consists of adding or replacing the current treatment with hydroxyzine or doxepin. If the individual doesn't respond to steps 1–3 then they are considered to have refractory symptoms. At this point, anti-inflammatory medications (dapsone, sulfasalazine), immunosuppressants (cyclosporin, sirolimus) or other medications like omalizumab can be used. These options are explained in more detail below.


title: Hives

text: Non-sedating antihistamines that block histamine H1 receptors are the first line of therapy. First-generation antihistamines, such as diphenhydramine or hydroxyzine, block both brain and peripheral H1 receptors, and cause sedation. Second-generation antihistamines, such as loratadine, cetirizine or desloratadine, selectively antagonize peripheral H1 receptors, and are less sedating, less anticholinergic, and generally preferred over the first-generation antihistamines. Fexofenadine, a new-generation antihistamine that blocks histamine H1 receptors, may be less sedating than some second-generation antihistamines.


title: Hives

text: People who do not respond to the maximum dose of H1 antihistamines may benefit from increasing the dose, then to switching to another non-sedating antihistamine, then to adding a leukotriene antagonist, then to using an older antihistamine, then to using systemic steroids and finally to using ciclosporin or omalizumab.


title: Hives

text: H2-receptor antagonists are sometimes used in addition to H1-antagonists to treat urticaria, but there is limited evidence for their efficacy.


title: Hives

text: Oral glucocorticoids are effective in controlling symptoms of chronic hives however they have an extensive list of adverse effects such as adrenal suppression, weight gain, osteoporosis, hyperglycemia, etc. Therefore, their use should be limited to a couple of weeks. In addition, one study found that systemic glucocorticoids combined with antihistamines did not hasten the time to symptom control compared with antihistamines alone.


title: Hives

text: Leukotrienes are released from mast cells along with histamine. The medications, montelukast and zafirlukast block leukotriene receptors and can be used as add on treatment or in isolation for people with CU. It is important to note that these medications may be more beneficial for people with NSAID induced CU.


title: Hives

text: Other options for refractory symptoms of chronic hives include anti-inflammatory medications, omalizumab, and immunosuppressants.


title: Hives

text: Potential anti-inflammatory agents include dapsone, sulfasalazine, and hydroxychloroquine. Dapsone is a sulfone antimicrobial agent and is thought to suppress prostaglandin and leukotriene activity. It is helpful in therapy-refractory cases and is contraindicated in people with G6PD deficiency. Sulfasalazine, a 5-ASA derivative, is thought to alter adenosine release and inhibit IgE mediated mast cell degranulation, Sulfasalazine is a good option for people with anemia who cannot take dapsone. Hydroxychloroquine is an antimalarial agent that suppresses T lymphocytes. It has a low cost however it takes longer than dapsone or sulfasalazine to work.


title: Hives

text: Omalizumab was approved by the FDA in 2014 for people with hives 12 years old and above with chronic hives. It is a monoclonal antibody directed against IgE. Significant improvement in pruritus and quality of life was observed in a phase III, multicenter, randomized control trial.


title: Hives

text: Immunosuppressants used for CU include cyclosporine, tacrolimus, sirolimus, and mycophenolate. Calcineurin inhibitors, such as cyclosporine and tacrolimus, inhibit cell responsiveness to mast cell products and inhibit T cell activity. They are preferred by some experts to treat severe symptoms. Sirolimus and mycophenolate have less evidence for their use in the treatment of chronic hives but reports have shown them to be efficacious. Immunosuppressants are generally reserved as the last line of therapy for severe cases due to their potential for serious adverse effects.


title: Hives

text: The term "urticaria" was first used by the Scottish physician William Cullen in 1769. It originates from the Latin word "urtica", meaning stinging hair or nettle, as the classical presentation follows the contact with a perennial flowering plant "Urtica dioica". The history of urticaria dates back to 1000–2000 BC with its reference as a wind-type concealed rash in the book "The Yellow Emperor's Inner Classic" from "Huangdi Neijing". Hippocrates in the 4th century first described urticaria as "knidosis" after the Greek word "knido" for nettle. The discovery of mast cells by Paul Ehrlich in 1879 brought urticaria and similar conditions under a comprehensive idea of allergic conditions.


title: White flag

text: The white flag is an internationally recognized protective sign of truce or ceasefire, and for negotiation. It is also used to symbolize surrender, since it is often the weaker party that requests negotiation. It is also flown on ships serving as cartels. A white flag signifies to all that an approaching negotiator is unarmed, with an intent to surrender or a desire to communicate. Persons carrying or waving a white flag are not to be fired upon, nor are they allowed to open fire. The use of the flag to request parley is included in the Hague Conventions of 1899 and 1907:


title: White flag

text: The improper use of the flag is forbidden by the rules of war and constitutes a war crime of perfidy. There have been numerous reported cases of such behavior in conflicts, such as combatants using white flags as a ruse to approach and attack enemy combatants, or killings of combatants attempting to surrender by carrying white flags.


title: White flag

text: The first mention of the usage of white flags to surrender is made during the Eastern Han dynasty (AD 25–220). In the Roman Empire, the historian Cornelius Tacitus mentions a white flag of surrender in AD 109. Before that time, Roman armies would surrender by holding their shields above their heads. The white flag was widely used in the Middle Ages in Western Europe to indicate an intent to surrender. The color white was used generally to indicate a person was exempt from combat; heralds bore white wands, prisoners or hostages captured in battle would attach a piece of white paper to their hat or helmet, and garrisons that had surrendered and been promised safe passage would carry white batons.


title: White flag

text: Its use may have expanded across continents, e.g. Portuguese chronicler Gaspar Correia (writing in the 1550s), claims that in 1502, an Indian ruler, the Zamorin of Calicut, dispatched negotiators bearing a "white cloth tied to a stick", "as a sign of peace", to his enemy Vasco da Gama. In 1625, Hugo Grotius in "De jure belli ac pacis" (On the Law of War and Peace), one of the foundational texts in international law, recognized the white flag as a "sign, to which use has given a signification"; it was "a tacit sign of demanding a parley, and shall be as obligatory, as if expressed by words".


title: White flag

text: The Umayyad dynasty (661–750) used white as their symbolic color as a reminder of Muhammad's first battle at Badr.


title: White flag

text: The Alids and the Fatimid dynasty also used white in opposition to the Abbasids, who used black as their dynastic color.


title: White flag

text: During the period of the Ancien Régime, starting in the early 17th century, the royal standard of France became a plain white flag as a symbol of purity, sometimes covered in fleur-de-lis when in the presence of the king or bearing the ensigns of the Order of the Holy Spirit.


title: White flag

text: The white color was also used as a symbol of military command, by the commanding officer of a French army. It would be featured on a white scarf attached to the regimental flag as to recognize French units from foreign ones and avoid friendly fire incidents. The French troops fighting in the American Revolutionary War fought under the white flag.


title: White flag

text: The French Navy used a plain white ensign for ships of the line. Smaller ships might have used other standards, such as a fleur-de-lis on white field. Commerce and private ships were authorized to use their own designs to represent France, but were forbidden to fly the white ensign.


title: White flag

text: During the French Revolution, in 1794, the blue, white and red Tricolore was adopted as the official national flag. The white flag quickly became a symbol of French royalists. (The white part of the French Tricolor is itself originally derived from the old Royal flag, the tricolor having been designed when the revolution still aimed at constitutional monarchy rather than a republic; this aspect of the Tricolor was, however, soon forgotten.)


title: White flag

text: During the Bourbon Restoration, the white flag replaced the Tricolore, which by then was seen as a symbol of regicide.


title: White flag

text: It was finally abandoned in 1830, with the July Revolution, with the definitive use of the blue, white and red flag.


title: White flag

text: In 1873, an attempt to reestablish the monarchy failed when Henri of Artois, the Count of Chambord refused to accept the Tricolore. He demanded the return of the white flag before he would accept the throne, a condition that proved unacceptable.


title: White flag

text: In 1863, the Confederate States adopted a new flag that played on the popularity of the Confederate Battle Flag, using a pure white field with the Battle Flag displayed in a canton (in a position equivalent to the stars on the flag of the United States). The white color, according to the Confederates, symbolized "supremacy of the white man over the inferior or colored race", and was dubbed "The White Man's Flag". The design lasted until March 1865, when concerns about its being mistaken for a flag of truce when the flag was not completely flying necessitated the addition of a broad red band on the fly edge.


title: White flag

text: The Christian Flag, designed in the early 20th century to represent all of Christianity and Christendom, has a white field, with a red Latin cross inside a blue canton. In conventional vexillology, a white flag is linked to surrender, a reference to the Biblical description of Jesus's non-violence and surrender to God's will.


title: White flag

text: In FIA sanctioned races, a white flag warns of a slow car ahead. In non-FIA races, a white racing flag is displayed from the starter's tower to indicate that the race leader is running the final lap. The white flag can be pointed at the race leader to avoid confusion of other drivers. Drivers may wave a small white flag after a collision to indicate that they are uninjured.


title: White flag

text: In NASCAR and other racing leagues, a white flag symbolizes one more lap to go. After this, the checkered flag is waved. NASCAR sometimes has finishes that are coined as "green–white–checker finishes" because of the order of the flags waved lap after lap before the finish.


title: White flag

text: In some Buddhist and Confucian countries, white is the colour of mourning, so a white flag is used where other cultures might fly a black flag.


title: White flag

text: During the Afghan Civil War, the Taliban used a plain white flag. When it took over Kabul in 1996, and established the Islamic Emirate of Afghanistan, the white flag became the national flag of the country. After 1997, the Taliban added the Shahadah to the flag.


title: White flag

text: During the Genpei War (1180–1185), the Minamoto clan fought under a white flag while the Taira clan fought under a red flag. As successive shogunates were from the Minamoto clan, this usage continued to the end of Tokugawa shogunate in 1868 when the current international usage was adopted.


title: White flag

text: Flags intending to bring peace to a conflicted territory have been based on a defaced version of a white flag:


title: White flag

text: The conceptual country of Nutopia was created by John Lennon and Yoko Ono in 1973, as a satirical response to Lennon's then-ongoing immigration problems. The Nutopian flag is solid white. Some criticised the association with the white flag of surrender, but Lennon and Ono defended it as representational of compromise and peace.


title: White flag

text: The flag of the Stewards of Gondor in the Middle-earth legendarium of J.R.R. Tolkien was solid white.


title: White flag

text: In March 2020, the Belgian Royal Palace in Brussels raised a white flag to support and express gratitude for caring staff amid coronavirus outbreak. Many Belgians also displayed a white flag in front of their house for the same reason.


title: White flag

text: Malaysian people launched a movement with hashtag #benderaputih (English: #whiteflag) on social media, urging those struggling financially and in need of food and essentials to fly a white flag outside their homes.


title: White flag

text: In November 2022, several widespread protests happened in mainland China against excess government control over Covid restrictions. People fears of government censorship were holding a sheet of white paper to express their fears and angers to the government.


title: White flag

text: “Chinese protesters have turned to blank sheets of paper to express their anger over COVID-19 restrictions in a rare, widespread outpouring of public dissent that has gone beyond social media to some of China's streets and top universities.


title: White flag

text: Images and videos circulated online showed students at universities in cities including Nanjing and Beijing holding up blank sheets of paper in silent protest, a tactic used in part to evade censorship or arrest.”


title: Exchange-traded fund

text: An exchange-traded fund (ETF) is a type of investment fund and exchange-traded product, i.e. they are traded on stock exchanges. ETFs are similar in many ways to mutual funds, except that ETFs are bought and sold from other owners throughout the day on stock exchanges whereas mutual funds are bought and sold from the issuer based on their price at day's end. An ETF holds assets such as stocks, bonds, currencies, futures contracts, and/or commodities such as gold bars, and generally operates with an arbitrage mechanism designed to keep it trading close to its net asset value, although deviations can occasionally occur. Most ETFs are index funds: that is, they hold the same securities in the same proportions as a certain stock market index or bond market index. The most popular ETFs in the U.S. replicate the S&P 500, the total market index, the NASDAQ-100 index, the price of gold, the "growth" stocks in the Russell 1000 Index, or the index of the largest technology companies. With the exception of non-transparent actively managed ETFs, in most cases, the list of stocks that each ETF owns, as well as their weightings, is posted daily on the website of the issuer. The largest ETFs have annual fees of 0.03% of the amount invested, or even lower, although specialty ETFs can have annual fees well in excess of 1% of the amount invested. These fees are paid to the ETF issuer out of dividends received from the underlying holdings or from selling assets.


title: Exchange-traded fund

text: An ETF divides ownership of itself into shares that are held by shareholders. The details of the structure (such as a corporation or trust) will vary by country, and even within one country there may be multiple possible structures. The shareholders indirectly own the assets of the fund, and they will typically get annual reports. Shareholders are entitled to a share of the profits, such as interest or dividends, and they would be entitled to any residual value if the fund undergoes liquidation.


title: Exchange-traded fund

text: As of August 2021, $9 trillion was invested in ETFs globally, including $6.6 trillion invested in the U.S.


title: Exchange-traded fund

text: In the U.S., the largest ETF issuers are BlackRock iShares with a 35% market share, The Vanguard Group with a 28% market share, State Street Global Advisors with a 14% market share, Invesco with a 5% market share, and Charles Schwab Corporation with a 4% market share.


title: Exchange-traded fund

text: Closed-end funds are not considered to be ETFs, even though they are funds and are traded on an exchange. Exchange-traded notes are debt instruments that are not exchange-traded funds.


title: Exchange-traded fund

text: Among the advantages of ETFs are the following, some of which derive from the status of most ETFs as index funds:


title: Exchange-traded fund

text: Since most ETFs are index funds, they incur low expense ratios because they are not actively managed. An index fund is much simpler to run, since it does not require security selection, and can be done largely by computer.


title: Exchange-traded fund

text: Unlike mutual funds, ETFs do not have to buy and sell securities to accommodate shareholder purchases and redemptions. And thus, an ETF does not have to maintain a cash reserve for redemptions and saves on brokerage expenses. ETFs typically have extremely low marketing, distribution and accounting expenses, and most ETFs do not have 12b-1 fees.


title: Exchange-traded fund

text: Over the long term, these cost differences can compound into a noticeable difference. However, some mutual funds are index funds as well and also have very low expense ratios, and some specialty ETFs have high expense ratios.


title: Exchange-traded fund

text: To the extent a stockbroker charges brokerage commissions, because ETFs trade on stock exchanges, each transaction may be subject to a brokerage commission. In addition, sales of ETFs in the United States are subject to transaction fees that the national securities exchanges must pay to the SEC under section 31 of the Securities Exchange Act of 1934, currently 0.00221% of the net proceeds from the transaction. Mutual funds are not subject to commissions and SEC fees; however, some mutual funds charge front-end or back-end loads, while ETFs do not have loads at all.


title: Exchange-traded fund

text: Unless the investment is sold, ETFs generally generate no capital gains taxes, because they typically have low turnover of their portfolio securities. While this is an advantage they share with other index funds, their tax efficiency compared to mutual funds is further enhanced because ETFs do not have to sell securities to meet investor redemptions.


title: Exchange-traded fund

text: In the U.S., whenever a mutual fund realizes a capital gain that is not balanced by a realized loss, the mutual fund must "distribute" the capital gains to its shareholders and the shareholders must pay capital gains taxes on the amount of the gain (unless such investment is held in an individual retirement account), even if the distribution is reinvested. This can happen whenever the mutual fund sells portfolio securities, whether to reallocate its investments or to fund shareholder redemptions. In contrast, ETFs are not redeemed by investors; any investor who wants to liquidate generally would sell the ETF shares on the secondary market, so investors generally only realize capital gains when they sell their own shares for a gain.


title: Exchange-traded fund

text: In most cases, ETFs are more tax-efficient than mutual funds in the same asset classes or categories.


title: Exchange-traded fund

text: An exception is some ETFs offered by The Vanguard Group, which are simply a different share class of their mutual funds. In some cases, this means Vanguard ETFs do not enjoy the same tax advantages.


title: Exchange-traded fund

text: In other cases, Vanguard uses the ETF structure to let the entire fund defer capital gains, benefiting both the ETF holders and mutual fund holders.


title: Exchange-traded fund

text: In the United Kingdom, ETFs can be shielded from capital gains tax by investing in them via an Individual Savings Account (ISA) or Self-Invested Personal Pension (SIPP), in the same manner as many other shares. Because UK-resident ETFs would be liable for UK corporation tax on non-UK dividends, most ETFs which hold non-UK companies sold to UK investors are issued in Ireland or Luxembourg.


title: Exchange-traded fund

text: The tax efficiency of ETFs are of no relevance for investors using tax-deferred accounts or investors who are tax-exempt, such as certain nonprofit organizations.


title: Exchange-traded fund

text: ETFs can be bought and sold at current market prices at any time during the trading day, unlike mutual funds and unit investment trusts, which can only be traded at the end of the trading day. Also unlike mutual funds, since ETFs are publicly traded securities, investors can execute the same types of trades that they can with a stock, such as limit orders, which allow investors to specify the price points at which they are willing to trade, stop-loss orders, margin buying, hedging strategies, and there is no minimum investment requirement. Because ETFs can be cheaply acquired, held, and disposed of, some investors buy and hold ETFs for asset allocation purposes, while other investors trade ETF shares frequently to hedge risk or implement market timing investment strategies.


title: Exchange-traded fund

text: Options, including put options and call options, can be written or purchased on most ETFs – which is not possible with mutual funds. Covered call strategies allow investors and traders to potentially increase their returns on their ETF purchases by collecting premiums (the proceeds of a call sale or write) on call options written against them. There are also ETFs that use the covered call strategy to reduce volatility and simplify the covered call process.


title: Exchange-traded fund

text: If they track a broad index, ETFs can provide some level of diversification. Like many mutual funds, ETFs provide an economical way to rebalance portfolio allocations and to invest cash quickly. An index ETF inherently provides diversification across an entire index, which can include broad-based international and country-specific indices, industry sector-specific indices, bond indices, and commodities.


title: Exchange-traded fund

text: The SEC generally requires ETFs to be transparent and issuers generally are required to publish the composition of the ETF portfolios daily on their websites. However, the SEC does allow certain actively managed ETFs to be non-transparent - i.e. they do not have to disclose exactly what they own.


title: Exchange-traded fund

text: In the United States, most ETFs are structured as open-end management investment companies, the same structure used by mutual funds and money market funds, although a few ETFs, including some of the largest ones, are structured as unit investment trusts. ETFs structured as open-end funds have greater flexibility in constructing a portfolio and are not prohibited from participating in securities lending programs or from using futures and options in achieving their investment objectives.


title: Exchange-traded fund

text: Most ETFs are index funds that attempt to replicate the performance of a specific index. Indexes may be based on the values of stocks, bonds, commodities, or currencies. An index fund seeks to track the performance of an index by holding in its portfolio either the contents of the index or a representative sample of the securities in the index.


title: Exchange-traded fund

text: Many funds track U.S. stock market indexes; for example, Vanguard Total Stock Market ETF () tracks the CRSP U.S. Total Market Index, and ETFs that track the S&P 500 are issued by The Vanguard Group (), iShares (), and State Street Corporation (). Other funds track international stock indexes; for example, Vanguard Total International Stock Index () tracks the MSCI All Country World ex USA Investable Market Index, while the iShares MSCI EAFE Index () tracks the MSCI EAFE Index, both invest solely in companies that are not based in the United States. Many smaller ETFs use unknown, untested indices.


title: Exchange-traded fund

text: ETFs replicate indexes and such indexes have varying investment criteria, such as minimum or maximum market capitalization of each holding. For example, the S&P 500 only contains large- and mid-cap stocks, so any ETF that tracks this index will not contain small-capitalization stocks. Others such as iShares Russell 2000 Index replicate an index composed only of small-cap stocks. There are many style ETFs such as iShares Russell 1000 Growth and iShares Russell 1000 Value. The iShares Select Dividend ETF replicates an index of high dividend paying stocks. Other indexes, on which ETFs are based, focus on a specific industry, such as banks or technology, or specific niche areas, such as sustainable energy or environmental, social and corporate governance. They can also focus on stocks in one country or be global.


title: Exchange-traded fund

text: There are also ETFs, such as Factor ETFs, that use enhanced indexing, which is an attempt to slightly beat the performance of an index using active management.


title: Exchange-traded fund

text: Exchange-traded funds that invest in bonds are known as bond ETFs. Government bond ETFs thrive during economic recessions because investors sell stocks and buy safer treasury bonds.


title: Exchange-traded fund

text: Some index ETFs invest 100% of their assets proportionately in the securities underlying an index, a manner of investing called replication. Other index ETFs such as the Vanguard Total Stock Market Index Fund, use representative sampling, investing 80% to 95% of their assets in the securities of an underlying index and investing the remaining 5% to 20% of their assets in other holdings, such as futures, option and swap contracts, and securities not in the underlying index, that the fund's adviser believes will help the ETF to achieve its investment objective. There are various ways the ETF can be weighted, such as equal weighting or revenue weighting. For index ETFs that invest in indices with thousands of underlying securities, some index ETFs employ "aggressive sampling" and invest in only a tiny percentage of the underlying securities.


title: Exchange-traded fund

text: Some index ETFs, such as leveraged ETFs or inverse ETFs, use investments in derivatives to seek a return that corresponds to a multiple of, or the inverse (opposite) of, the daily performance of the index.


title: Exchange-traded fund

text: Commodity ETFs invest in commodities such as precious metals, agricultural products, or hydrocarbons such as petroleum. They are similar to ETFs that invest in securities, and trade just like shares; however, because they do not invest in securities, commodity ETFs are not regulated as investment companies under the Investment Company Act of 1940 in the United States, although their public offering is subject to review by the U.S. Securities and Exchange Commission (SEC) and they need an SEC no-action letter under the Securities Exchange Act of 1934. They may, however, be subject to regulation by the Commodity Futures Trading Commission.


title: Exchange-traded fund

text: Commodity ETFs are generally structured as exchange-traded grantor trusts, which gives a direct interest in a fixed portfolio. SPDR Gold Shares, a gold exchange-traded fund, is a grantor trust, and each share represents ownership of one-tenth of an ounce of gold.


title: Exchange-traded fund

text: Most commodity ETFs own the physical commodity. SPDR Gold Shares () owns over 40 million ounces of gold in trust, iShares Silver Trust () owns 18,000 tons of silver, Aberdeen Standard Physical Palladium Shares () owns almost 200,000 ounces of palladium, and Aberdeen Standard Physical Platinum Shares ETF () owns over 1.1 million ounces of platinum. However, many ETFs such as the United States Oil Fund by United States Commodity Funds () only own futures contracts, which may produce quite different results from owning the commodity. In these cases, the funds simply roll the delivery month of the contracts forward from month to month. This does give exposure to the commodity, but subjects the investor to risks involved in different prices along the term structure, such as a high cost to roll. They can also be index funds tracking commodity indices.


title: Exchange-traded fund

text: Currency ETFs enable investors to invest in or short any major currency or a basket of currencies. They are issued by Invesco and Deutsche Bank among others. Investors can profit from the foreign exchange spot change, while receiving local institutional interest rates, and a collateral yield.


title: Exchange-traded fund

text: While most ETFs are index funds, some ETFs, particularly bond ETFs, do have active management. Actively managed ETFs are usually fully transparent, publishing their current securities portfolios on their websites daily. But some actively managed ETFs are not fully transparent. A transparent actively managed ETF is at risk from arbitrage activities by people who might engage in front running since the daily portfolio reports can reveal the manager's trading strategy. Some actively managed equity ETFs address this problem by trading only weekly or monthly. Actively managed debt ETFs, which are less susceptible to front-running, trade more frequently.


title: Exchange-traded fund

text: Actively managed bond ETFs are not at much of a disadvantage to bond market index funds since concerns about disclosing bond holdings are less pronounced and there are fewer product choices.


title: Exchange-traded fund

text: The largest actively managed ETFs, each bond ETFs with approximately $14 billion in assets, are the JPMorgan Ultra-Short Income ETF (), which charges 0.18% in annual fees, and the Pimco Enhanced Short Duration ETF (), which charges 0.36% in annual fees.


title: Exchange-traded fund

text: Actively managed ETFs compete with actively managed mutual funds. While both seek to outperform the market or their benchmark and rely on portfolio managers to choose which stocks and bonds the funds will hold, there are four major ways they differ. Unlike actively managed mutual funds, actively managed ETFs trade on a stock exchange, can be sold short, can be purchased on margin and have a tax-efficient structure.


title: Exchange-traded fund

text: Inverse ETFs are constructed by using various derivatives for the purpose of profiting from a decline in the value of the underlying benchmark or index. It is a similar type of investment to holding several short positions or using a combination of advanced investment strategies to profit from falling prices. Many inverse ETFs use daily futures as their underlying benchmark.


title: Exchange-traded fund

text: Leveraged exchange-traded funds (LETFs or leveraged ETFs) attempt to achieve daily returns that are a multiple of the returns of the corresponding index. Leveraged index ETFs are often marketed as bull or bear funds. For example, a leveraged bull ETF fund might attempt to achieve daily returns that are 2x or 3x those of the Dow Jones Industrial Average or the S&P 500. A leveraged inverse exchange-traded fund may attempt to achieve returns that are -2x or -3x the daily index return, meaning that it will gain double or triple the loss of the market. To achieve these results, the issuers use various financial engineering techniques, including equity swaps, derivatives, futures contracts, and rebalancing, and re-indexing.


title: Exchange-traded fund

text: Direxion offers leveraged ETFs that attempt to produce 3x the daily result of either investing in () or shorting () the S&P 500.


title: Exchange-traded fund

text: The rebalancing and re-indexing of leveraged ETFs may have considerable costs when markets are volatile. Leveraged ETFs effectively increase exposure ahead of a losing session and decrease exposure ahead of a winning session. The rebalancing problem is that the fund manager incurs trading losses because he needs to buy when the index goes up and sell when the index goes down in order to maintain a fixed leverage ratio. A 2.5% daily change in the index will for example reduce value of a -2x bear fund by about 0.18% per day, which means that about a third of the fund may be wasted in trading losses within a year (1-(1-0.18%)=36.5%). Investors may however circumvent this problem by buying or writing futures directly, accepting a varying leverage ratio. A more reasonable estimate of daily market changes is 0.5%, which leads to a 2.6% yearly loss of principal in a 3x leveraged fund.


title: Exchange-traded fund

text: The re-indexing problem of leveraged ETFs stems from the arithmetic effect of volatility of the underlying index. Take, for example, an index that begins at 100 and a 2X fund based on that index that also starts at 100. In a first trading period (for example, a day), the index rises 10% to 110. The 2X fund will then rise 20% to 120. The index then drops back to 100 (a drop of 9.09%), so that it is now even. The drop in the 2X fund will be 18.18% (2*9.09). But 18.18% of 120 is 21.82. This puts the value of the 2X fund at 98.18. Even though the index is unchanged after two trading periods, an investor in the 2X fund would have lost 1.82%. This decline in value can be even greater for inverse funds (leveraged funds with negative multipliers such as -1, -2, or -3). It always occurs when the change in value of the underlying index changes direction. And the decay in value increases with volatility of the underlying index.


title: Exchange-traded fund

text: The effect of leverage is also reflected in the pricing of options written on leveraged ETFs. In particular, the terminal payoff of a leveraged ETF European/American put or call depends on the realized variance (hence the path) of the underlying index. The impact of leverage ratio can also be observed from the implied volatility surfaces of leveraged ETF options. For instance, the implied volatility curves of inverse leveraged ETFs (with negative multipliers such as -1, -2, or -3) are commonly observed to be increasing in strike, which is characteristically different from the implied volatility smiles or skews seen for index options or non-leveraged ETF options.


title: Exchange-traded fund

text: In May 2017, the SEC granted approval of two 4x leveraged ETF related to S&P 500 futures, the ForceShares Daily 4X US Market Futures Long Fund, and ForceShares Daily 4X US Market Futures Short Fund, before rescinding the approval a few weeks later.


title: Exchange-traded fund

text: In November 2019, the SEC proposed a rule regarding the use of derivatives that would make it easier for leveraged and inverse ETFs to come to market, including eliminating a liquidity rule to cover obligations of derivatives positions, replacing it with a risk management program overseen by a derivatives risk manager. The SEC also proposed rules requiring investors to answer a series of questions before being permitted to invest in leveraged ETFs.


title: Exchange-traded fund

text: Thematic ETFs typically focus on long-term, societal trends, such as disruptive technologies, climate change, or shifting consumer behaviors. Some of the most popular themes include cloud computing, robotics, and electric vehicles, as well as the gig economy, e-commerce, and clean energy. As of June 2019, 13 U.S.-listed thematic ETFs held more than US$1 billion in assets and another nine held more than US$500 million. In Canada, no Canadian-listed thematic ETF holds more than $500 million, with the fund category holding about $2.5 billion as of January 2020.


title: Exchange-traded fund

text: ETFs had their genesis in 1989 with Index Participation Shares (IPS), an S&P 500 proxy that traded on the American Stock Exchange and the Philadelphia Stock Exchange. This product was short-lived after a lawsuit by the Chicago Mercantile Exchange was successful in stopping sales in the United States. The argument against the IPS approach was that it resembled a futures contract because the investments held an index, rather than holding the actual underlying stocks.


title: Exchange-traded fund

text: In 1990, a similar product, Toronto Index Participation Shares, which tracked the TSE 35 and later the TSE 100 indices, started trading on the Toronto Stock Exchange (TSE) in 1990. The popularity of these products led the American Stock Exchange to try to develop something that would satisfy regulations by the U.S. Securities and Exchange Commission.


title: Exchange-traded fund

text: Nathan Most and Steven Bloom, under the direction of Ivers Riley, designed and developed Standard & Poor's Depositary Receipts (), which were introduced in January 1993. Known as SPDRs or "Spiders", the fund became the largest ETF in the world. In May 1995, State Street Global Advisors introduced the S&P 400 MidCap SPDRs ().


title: Exchange-traded fund

text: Barclays, in conjunction with MSCI and Funds Distributor Inc., entered the market in 1996 with World Equity Benchmark Shares (WEBS), which became iShares MSCI Index Fund Shares. WEBS originally tracked 17 MSCI country indices managed by the funds' index provider, Morgan Stanley. WEBS were particularly innovative because they gave casual investors easy access to foreign markets. While SPDRs were organized as unit investment trusts, WEBS were set up as a mutual fund, the first of their kind.


title: Exchange-traded fund

text: In 1998, State Street Global Advisors introduced "Sector Spiders", separate ETFs for each of the sectors of the S&P 500. Also in 1998, the "Dow Diamonds" () were introduced, tracking the Dow Jones Industrial Average. In 1999, the influential "cubes" was launched, with the goal of replicate the price movement of the NASDAQ-100 – originally "QQQQ" but later .


title: Exchange-traded fund

text: The iShares line was launched in early 2000. By 2005, it had a 44% market share of ETF assets under management. Barclays Global Investors was sold to BlackRock in 2009.


title: Exchange-traded fund

text: In 2001, The Vanguard Group entered the market by launching the Vanguard Total Stock Market ETF (), which owns every publicly traded stock in the United States. Some of Vanguard's ETFs are a share class of an existing mutual fund.


title: Exchange-traded fund

text: iShares issued the first bond funds in July 2002: iShares IBoxx $ Invest Grade Corp Bond Fund (), which owns corporate bonds, and a TIPS fund. In 2007, iShares introduced an ETF that owns high-yield debt and an ETF that owns municipal bonds and State Street Global Advisors and The Vanguard Group also issued bond ETFs.


title: Exchange-traded fund

text: In December 2005, Rydex (now Invesco) launched the first currency ETF, the Euro Currency Trust (), which tracked the value of the Euro. In 2007, Deutsche Bank's db x-trackers launched the EONIA Total Return Index ETF in Frankfurt tracking the Euro. In 2008, it launched the Sterling Money Market ETF () and US Dollar Money Market ETF () in London. In November 2009, ETF Securities launched the world's largest FX platform tracking the MSFX Index covering 18 long or short USD ETC vs. single G10 currencies.


title: Exchange-traded fund

text: In 2008, the SEC authorized the creation of ETFs that use active management strategies. Bear Stearns launched the first actively managed ETF, the Current Yield ETF (), which began trading on the American Stock Exchange on March 25, 2008.


title: Exchange-traded fund

text: In December 2014, assets under management by U.S. ETFs reached $2 trillion. By November 2019, assets under management by U.S. ETFs reached $4 trillion. Assets under management by U.S. ETFs grew to $5.5 trillion by January 2021.


title: Exchange-traded fund

text: The first gold exchange-traded product was Central Fund of Canada, a closed-end fund founded in 1961. It amended its articles of incorporation in 1983 to provide investors with a product for ownership of gold and silver bullion. It has been listed on the Toronto Stock Exchange since 1966 and the American Stock Exchange since 1986.


title: Exchange-traded fund

text: The idea of a gold ETF was first conceptualized by Benchmark Asset Management Company Private Ltd in India, which filed a proposal with the Securities and Exchange Board of India in May 2002. In March 2007 after delays in obtaining regulatory approval. The first gold exchange-traded fund was Gold Bullion Securities launched on the ASX in 2003, and the first silver exchange-traded fund was iShares Silver Trust launched on the NYSE in 2006. SPDR Gold Shares, a commodity ETF, is in the top 10 largest ETFs by assets under management.


title: Exchange-traded fund

text: Unlike mutual funds, ETFs do not sell or redeem their individual shares at net asset value. Instead, financial institutions purchase and redeem ETF shares directly from the ETF, but only in large blocks (such as 50,000 shares), called creation units. Purchases and redemptions of the creation units generally are in kind, with the institutional investor contributing or receiving a basket of securities of the same type and proportion held by the ETF, although some ETFs may require or permit a purchasing or redeeming shareholder to substitute cash for some or all of the securities in the basket of assets.


title: Exchange-traded fund

text: The ability to purchase and redeem creation units gives ETFs an arbitrage mechanism intended to minimize the potential deviation between the market price and the net asset value of ETF shares. ETFs generally have transparent portfolios, so institutional investors know exactly what portfolio assets they must assemble if they wish to purchase a creation unit, and the exchange disseminates the updated net asset value of the shares throughout the trading day, typically at 15-second intervals. ETF distributors only buy or sell ETFs directly from or to authorized participants, which are large broker-dealers with whom they have entered into agreements—and then, only in creation units, which are large blocks of tens of thousands of ETF shares, usually exchanged in-kind with baskets of the underlying securities. Authorized participants may wish to invest in the ETF shares for the long term, but they usually act as market makers on the open market, using their ability to exchange creation units with their underlying securities to provide market liquidity of the ETF shares and help ensure that their intraday market price approximates the net asset value of the underlying assets. Other investors, such as individuals using a retail broker, trade ETF shares on this secondary market.


title: Exchange-traded fund

text: If there is strong investor demand for an ETF, its share price will temporarily rise above its net asset value per share, giving arbitrageurs an incentive to purchase additional creation units from the ETF and sell the component ETF shares in the open market. The additional supply of ETF shares reduces the market price per share, generally eliminating the premium over net asset value. A similar process applies when there is weak demand for an ETF: its shares trade at a discount from net asset value.


title: Exchange-traded fund

text: When new shares of an ETF are created due to increased demand, this is referred to as ETF inflows. When ETF shares are converted into the component securities, this is referred to as ETF outflows.


title: Exchange-traded fund

text: ETFs are dependent on the efficacy of the arbitrage mechanism in order for their share price to track net asset value.


title: Exchange-traded fund

text: The ETF tracking error is the difference between the returns of the ETF and its reference index or asset. A non-zero tracking error therefore represents a failure to replicate the reference as stated in the ETF prospectus. The tracking error is computed based on the prevailing price of the ETF and its reference. It is different from the premium/discount which is the difference between the ETF's NAV (updated only once a day) and its market price. Tracking errors are more significant when the ETF provider uses strategies other than full replication of the underlying index. Some of the most liquid equity ETFs tend to have better tracking performance because the underlying index is also sufficiently liquid, allowing for full replication. In contrast, some ETFs, such as commodities ETFs and their leveraged ETFs, do not necessarily employ full replication because the physical assets cannot be stored easily or used to create a leveraged exposure, or the reference asset or index is illiquid. Futures-based ETFs may also suffer from negative roll yields, as seen in the VIX futures market.


title: Exchange-traded fund

text: While tracking errors are generally non-existent for the most popular ETFs, they have existed during periods of market turbulence such as in late 2008 and 2009 and during flash crashes, particularly for ETFs that invest in foreign or emerging-market stocks, future-contracts based commodity indices, and high-yield debt. In November 2008, during a period of market turbulence, some lightly traded ETFs frequently had deviations of 5% or more, exceeding 10% in a handful of cases, although even for these niche ETFs, the average deviation was only a little more than 1%. The trades with the greatest deviations tended to be made immediately after the market opened. Per Morgan Stanley, in 2009, ETFs missed their targets by an average of 1.25 percentage points, a gap more than twice as wide as the 0.52-percentage-point average they posted in 2008.


title: Exchange-traded fund

text: ETFs have a wide range of liquidity. The most popular ETFs (such as those tracking the S&P 500) are constantly traded, with tens of millions of shares per day changing hands, while others trade in much lower numbers. There are many ETFs that do not trade very often, and thus might be difficult to sell compared to more liquid ETFs. The most active ETFs are "very" liquid, with high regular trading volume and tight bid-ask spreads (the gap between buyer and seller's prices), and the price thus fluctuates throughout the day. This is in contrast with mutual funds, where all purchases or sales on a given day are executed at the same price at the end of the trading day.


title: Exchange-traded fund

text: New regulations to force ETFs to be able to manage systemic stresses were put in place following the 2010 flash crash, when prices of ETFs and other stocks and options became volatile, with trading markets spiking and bids falling as low as a penny a share in what the Commodity Futures Trading Commission (CFTC) investigation described as one of the most turbulent periods in the history of financial markets.


title: Exchange-traded fund

text: These regulations proved to be inadequate to protect investors in the August 24, 2015, flash crash, "when the price of many ETFs appeared to come unhinged from their underlying value." ETFs were consequently put under even greater scrutiny by regulators and investors. Analysts at Morningstar, Inc. claimed in December 2015 that "ETFs are a 'digital-age technology' governed by 'Depression-era legislation".


title: Exchange-traded fund

text: Synthetic ETFs, which do not own securities but track indexes using derivatives and swaps, have raised concern due to lack of transparency in products and increasing complexity; conflicts of interest; and lack of regulatory compliance.


title: Exchange-traded fund

text: A synthetic ETF has counterparty risk, because the counterparty is contractually obligated to match the return on the index. The deal is arranged with collateral posted by the swap counterparty. A potential hazard is that the investment bank offering the ETF might post its own collateral, and that collateral could be of dubious quality. Furthermore, the investment bank could use its own trading desk as counterparty. These types of set-ups are not allowed under the European guidelines, Undertakings for Collective Investment in Transferable Securities Directive 2009 (UCITS).


title: Exchange-traded fund

text: Per the International Monetary Fund, "Some market participants believe the growing popularity of exchange-traded funds (ETFs) may have contributed to equity price appreciation in some emerging economies, and warn that leverage embedded in ETFs could pose financial stability risks if equity prices were to decline for a protracted period."


title: Exchange-traded fund

text: Some critics claim that ETFs can be, and have been, used to manipulate market prices, such as in conjunction with short selling that contributed to the United States bear market of 2007–2009.


title: Exchange-traded fund

text: The first European ETF came on the market in 2000 and the European ETF market has seen tremendous growth since. At the end of March 2019, the asset under management in the European industry stood at €760bn, compared with an amount of €100bn at the end of 2008. The market share of ETFs has increased significantly in recent years. At the end of March 2019, ETFs account for 8.6% of total AUM in investment funds in Europe, up from 5.5% five years earlier.


title: Exchange-traded fund

text: The use of ETFs has also evolved over time, as shown by regular observations of investment professionals’ practices in Europe. EDHEC surveys show an increasing propagation of ETF adoption over the years, especially for traditional asset classes. While ETFs are now used across a wide spectrum of asset classes, in 2019 the main use is currently in the area of equities and sectors, for 91% (45% in 2006) and 83% of the survey respondents, respectively. This is likely to be linked to the popularity of indexing in these asset classes, as well as to the fact that equity indices and sector indices are based on highly liquid instruments, which makes it straightforward to create ETFs on such underlying securities. The other asset classes for which a large share of investors declare using ETFs are commodities and corporate bonds (68% for them both, to be compared with 6% and 15% in 2006, respectively), smart beta-factor investing and government bonds (66% for them both, to be compared with 13% for government bonds in 2006).


title: Exchange-traded fund

text: Investors have a high rate of satisfaction with ETFs, especially for traditional asset classes. In 2019, we observe 95% satisfaction for both equities and government bond asset.


title: Exchange-traded fund

text: Over the years, EDHEC survey results have consistently indicated that ETFs were used as part of a truly passive investment approach, mainly for long-term buy-and-hold investment, rather than tactical allocation. However, over the past three years, the two approaches have gradually become more balanced and, in 2019, European investment professionals declare that their use of ETFs for tactical allocation is actually greater than for long term positions (53% and 51% respectively).


title: Exchange-traded fund

text: ETFs, which originally replicated broad market indices, are now available in a wide variety of asset classes and a multitude of market sub-segments (sectors, styles, etc.) If gaining broad market exposure remains the main focus of ETFs for 73% of users in 2019, 52% of respondents declare using ETFs to obtain specific sub-segment exposure. The diversity of ETFs increases the possibilities of using ETFs for tactical allocation. Investors can easily increase or decrease their portfolio exposure to a specific style, sector, or factor at lower cost with ETFs. The more volatile the markets are, the more interesting it is to use low cost instruments for tactical allocation, especially that cost is a major criterion for selecting an ETF provider for 88% of respondents.


title: Exchange-traded fund

text: Despite a high current adoption rate of ETFs and the already high maturity of this market, a high percentage of investors (46%) still plan to increase their use of ETFs in the future, according to the EDHEC 2019 survey responses. Investors are planning to increase their ETF allocation to replace active managers (71% of respondents in 2019), but are also seeking to replace other passive investing products through ETFs (42% of respondents in 2019). Lowering costs is the main motivation for increasing the use of ETFs for 74% of investors.


title: Exchange-traded fund

text: Investors are especially demanding for further developments of ETF products in the area of Ethical/SRI and smart beta equity / factor indices. In 2018, ESG ETFs enjoyed growth of 50%, reaching €9.95bn, with the launch of 36 new products, against just 15 in 2017. However, 31% of the EDHEC 2019 survey respondents still require additional ETF products based on sustainable investment, which appears to be their top concern.


title: Exchange-traded fund

text: Investors are also demanding for ETFs related to advanced forms of equity indices, namely those based on multi-factor and smart beta indices (30% and 28% of respondents, respectively), and 45% of respondents would like to see further developments in at least one category related to smart beta equity or factor indices (smart beta indices, single-factor indices and multi-factor indices).


title: Exchange-traded fund

text: Consistent with the desire to use ETFs for passive exposure to broad market indices, only 19% of respondents show any interest in future development of actively managed equity ETFs.


title: Mouse

text: A mouse (: mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse ("Mus musculus"). Mice are also popular as pets. In some places, certain kinds of field mice are locally common. They are known to invade homes for food and shelter.


title: Mouse

text: Mice are typically distinguished from rats by their size. Generally, when a muroid rodent is discovered, its common name includes the term "mouse" if it is smaller, or "rat" if it is larger. The common terms "rat" and "mouse" are not taxonomically specific. Typical mice are classified in the genus "Mus", but the term "mouse" is not confined to members of "Mus" and can also apply to species from other genera such as the deer mouse, "Peromyscus".


title: Mouse

text: Domestic mice sold as pets often differ substantially in size from the common house mouse. This is attributable to breeding and different conditions in the wild. The best-known strain of mouse is the white lab mouse. It has more uniform traits that are appropriate to its use in research.


title: Mouse

text: Cats, wild dogs, foxes, birds of prey, snakes and even certain kinds of arthropods have been known to prey heavily upon mice. Despite this, mice populations remain plentiful. Due to its remarkable adaptability to almost any environment, the mouse is one of the most successful mammalian genera living on Earth today.


title: Mouse

text: In certain contexts, mice can be considered vermin. Vermin are a major source of crop damage, as they are known to cause structural damage and spread disease. Mice spread disease through their feces and are often carriers of parasites. In North America, breathing dust that has come in contact with mouse excrement has been linked to hantavirus, which may lead to hantavirus pulmonary syndrome (HPS).


title: Mouse

text: Primarily nocturnal animals, mice compensate for their poor eyesight with a keen sense of hearing. They depend on their sense of smell to locate food and avoid predators.


title: Mouse

text: In the wild, mice are known to build intricate burrows. These burrows have long entrances and are equipped with escape tunnels. In at least one species, the architectural design of a burrow is a genetic trait.


title: Mouse

text: The most common mice are murines, in the same clade as common rats. They are murids, along with gerbils and other close relatives.


title: Mouse

text: Researchers at the Max Planck Institute of Neurobiology have confirmed that mice have a range of facial expressions. They used machine vision to spot familiar human emotions like pleasure, disgust, nausea, pain, and fear.


title: Mouse

text: In nature, mice are largely herbivores, consuming any kind of fruit or grain from plants. However, mice adapt well to urban areas and are known for eating almost all types of food scraps. In captivity, mice are commonly fed commercial pelleted mouse diet. These diets are nutritionally complete, but they still need a large variety of vegetables.


title: Mouse

text: Despite popular belief, most mice do not have a special appetite for cheese. They will only eat cheese for lack of better options.


title: Mouse

text: Mice are common experimental animals in laboratory research of biology and psychology fields primarily because they are mammals, and also because they share a high degree of homology with humans. They are the most commonly used mammalian model organism, more common than rats. The mouse genome has been sequenced, and virtually all mouse genes have human homologs. The mouse has approximately 2.7 billion base pairs and 20 pairs of chromosomes.


title: Mouse

text: They can also be manipulated in ways that are illegal with humans, although animal rights activists often object. A knockout mouse is a genetically modified mouse that has had one or more of its genes made inoperable through a gene knockout.


title: Mouse

text: Reasons for common selection of mice are that they are small and inexpensive, have a widely varied diet, are easily maintained, and can reproduce quickly. Several generations of mice can be observed in a relatively short time. Mice are generally very docile if raised from birth and given sufficient human contact. However, certain strains have been known to be quite temperamental.


title: Mouse

text: Many people buy mice as companion pets. They can be playful, loving and can grow used to being handled. Like pet rats, pet mice should not be left unsupervised outside as they have many natural predators, including (but not limited to) birds, snakes, lizards, cats, and dogs. Male mice tend to have a stronger odor than the females. However, mice are careful groomers and as pets they never need bathing. Well looked-after mice can make ideal pets. Some common mouse care products are:


title: Mouse

text: Mice are a staple in the diet of many small carnivores. In various countries mice are used as feed for pets such as snakes, lizards, frogs, tarantulas, and birds of prey, and many pet stores carry mice for this purpose.


title: Mouse

text: Common terms used to refer to different ages/sizes of mice when sold for pet food are "pinkies", "fuzzies", "crawlers", "hoppers", and "adults". Pinkies are newborn mice that have not yet grown fur; fuzzies have some fur but are not very mobile; and hoppers have a full coat of hair and are fully mobile but are smaller than adult mice. Mice without fur are easier for the animal to consume; however, mice with fur may be more convincing as animal feed. These terms are also used to refer to the various growth stages of rats (see Fancy rat).


title: Mouse

text: Humans have eaten mice since prehistoric times. In Victorian Britain, fried mice were still given to children as a folk remedy for bed-wetting; while Jared Diamond reports creamed mice being used in England as a dietary supplement during WW II rationing. Mice are a delicacy throughout eastern Zambia and northern Malawi, where they are a seasonal source of protein. Field rat is a popular food in Vietnam and neighboring countries. In many countries, however, mouse is no longer a food item.


title: Mouse

text: Prescribed cures in Ancient Egypt included mice as medicine. In Ancient Egypt, when infants were ill, mice were eaten as treatment by their mothers. It was believed that mouse eating by the mother would help heal the baby who was ill.


title: Florence Cathedral

text: Florence Cathedral, formally the (; in English Cathedral of Saint Mary of the Flower), is the cathedral of Florence, Italy (). It was begun in 1296 in the Gothic style to a design of Arnolfo di Cambio and was structurally completed by 1436, with the dome engineered by Filippo Brunelleschi. The exterior of the basilica is faced with polychrome marble panels in various shades of green and pink, bordered by white, and has an elaborate 19th-century Gothic Revival façade by Emilio De Fabris.


title: Florence Cathedral

text: The cathedral complex, in Piazza del Duomo, includes the Baptistery and Giotto's Campanile. These three buildings are part of the UNESCO World Heritage Site covering the historic centre of Florence and are a major tourist attraction of Tuscany. The basilica is one of Italy's largest churches, and until the development of new structural materials in the modern era, the dome was the largest in the world. It remains the largest brick dome ever constructed.


title: Florence Cathedral

text: The cathedral is the mother church of the Archdiocese of Florence, whose archbishop is Giuseppe Betori.


title: Florence Cathedral

text: Santa Maria del Fiore was built on the site of Florence's second cathedral dedicated to Saint Reparata; the first was the Basilica di San Lorenzo di Firenze, the first building of which was consecrated as a church in 393 by St. Ambrose of Milan. The ancient structure, founded in the early 5th century and having undergone many repairs, was crumbling with age, according to the 14th-century "Nuova Cronica" of Giovanni Villani, and was no longer large enough to serve the growing population of the city. Other major Tuscan cities had undertaken ambitious reconstructions of their cathedrals during the Late Medieval period, such as Pisa and particularly Siena where the enormous proposed extensions were never completed.


title: Florence Cathedral

text: City council approved the design of Arnolfo di Cambio for the new church in 1294. Di Cambio was also architect of the church of Santa Croce and the Palazzo Vecchio. He designed three wide naves ending under the octagonal dome, with the middle nave covering the area of Santa Reparata. The first stone was laid on 9 September 1296, by Cardinal Valeriana, the first papal legate ever sent to Florence. The building of this vast project was to last 140 years; Arnolfo's plan for the eastern end, although maintained in concept, was greatly expanded in size.


title: Florence Cathedral

text: After Arnolfo died in 1302, work on the cathedral slowed for almost 50 years. When the relics of Saint Zenobius were discovered in 1330 in Santa Reparata, the project gained a new impetus. In 1331, the Arte della Lana, the guild of wool merchants, took over patronage for the construction of the cathedral and in 1334 appointed Giotto to oversee the work. Assisted by Andrea Pisano, Giotto continued di Cambio's design. His major accomplishment was the building of the campanile. When Giotto died on 8 January 1337, Andrea Pisano continued the building until work was halted due to the Black Death in 1348.


title: Florence Cathedral

text: In 1349, work resumed on the cathedral under a series of architects, starting with Francesco Talenti, who finished the campanile and enlarged the overall project to include the apse and the side chapels. In 1359, Talenti was succeeded by Giovanni di Lapo Ghini (1360–1369) who divided the centre nave in four square bays. Other architects were Alberto Arnoldi, Giovanni d'Ambrogio, Neri di Fioravanti and Andrea Orcagna. By 1375, the old church Santa Reparata was pulled down. The nave was finished by 1380, and only the dome remained incomplete until 1418.


title: Florence Cathedral

text: On 19 August 1418, the Arte della Lana announced an architectural design competition for erecting Neri's dome. The two main competitors were two master goldsmiths, Lorenzo Ghiberti and Filippo Brunelleschi, the latter of whom was supported by Cosimo de Medici. Ghiberti had been the winner of a competition for a pair of bronze doors for the Baptistery in 1401 and lifelong competition between the two remained sharp. Brunelleschi won and received the commission.


title: Florence Cathedral

text: Ghiberti, appointed coadjutor, drew a salary equal to Brunelleschi's and, though neither was awarded the announced prize of 200 florins, was promised equal credit, although he spent most of his time on other projects. When Brunelleschi became ill, or feigned illness, the project was briefly in the hands of Ghiberti. But Ghiberti soon had to admit that the whole project was beyond him. In 1423, Brunelleschi was back in charge and took over sole responsibility.


title: Florence Cathedral

text: Work on the dome began in 1420 and finished in 1436. The cathedral was consecrated by Pope Eugene IV on 25 March 1436, (the first day of the year according to the Florentine calendar). It was the first 'octagonal' dome in history to be built without a temporary wooden supporting frame. It was one of the most impressive projects of the Renaissance. During the consecration in 1436, Guillaume Dufay's motet "Nuper rosarum flores" was performed.


title: Florence Cathedral

text: The decoration of the exterior of the cathedral, begun in the 14th century, was not completed until 1887, when the polychrome marble façade was completed with the design of Emilio De Fabris. The floor of the church was relaid in marble tiles in the 16th century.


title: Florence Cathedral

text: The exterior walls are faced in alternate vertical and horizontal bands of polychrome marble from Carrara (white), Prato (green), Siena (red), Lavenza and a few other places. These marble bands had to repeat the already existing bands on the walls of the earlier adjacent baptistery the Battistero di San Giovanni and Giotto's Bell Tower. There are two side doors: the "Doors of the Canonici" (south side) and the "Door of the Mandorla" (north side) with sculptures by Nanni di Banco, Donatello, and Jacopo della Quercia. The six side windows, notable for their delicate tracery and ornaments, are separated by pilasters. Only the four windows closest to the transept admit light; the other two are merely ornamental. The clerestory windows are round, a common feature in Italian Gothic.


title: Florence Cathedral

text: The cathedral of Florence is built as a basilica, having a wide central nave of four square bays, with an aisle on either side. The chancel and transepts are of identical polygonal plan, separated by two smaller polygonal chapels. The whole plan forms a Latin cross. The nave and aisles are separated by wide pointed Gothic arches resting on composite piers.


title: Florence Cathedral

text: The dimensions of the building are enormous: building area , length , width , width at the crossing . The height of the arches in the aisles is . The height of the dome is . It has the fifth tallest dome in the world.


title: Florence Cathedral

text: The Overseers of the Office of Works of Florence Cathedral the Arte della Lana, had plans to commission a series of twelve large Old Testament sculptures for the buttresses of the cathedral. Donatello, then in his early twenties, was commissioned to carve a statue of David in 1408, to top one of the buttresses of Florence Cathedral, though it was never placed there. Nanni di Banco was commissioned to carve a marble statue of Isaiah, at the same scale, in the same year. One of the statues was lifted into place in 1409, but was found to be too small to be easily visible from the ground and was taken down; both statues then languished in the workshop of the "opera" for several years. In 1410 Donatello made the first of the statues, a figure of Joshua in terracotta. In 1409-1411 Donatello made a statue of "Saint John the Evangelist" which until 1588 was in a niche of the old cathedral façade. Between 1415 and 1426, Donatello created five statues for the campanile of Santa Maria del Fiore in Florence, also known as the Duomo. These works are the "Beardless Prophet"; "Bearded Prophet" (both from 1415); the "Sacrifice of Isaac" (1421); "Habbakuk" (1423–25); and "Jeremiah" (1423–26); which follow the classical models for orators and are characterized by strong portrait details. A figure of Hercules, also in terracotta, was commissioned from the Florentine sculptor Agostino di Duccio in 1463 and was made perhaps under Donatello's direction. A statue of David by Michelangelo was completed 1501-1504 although it could not be placed on the buttress because of its six-ton weight. In 2010 a fiberglass replica of "David" was placed for one day on the Florence cathedral.


title: Florence Cathedral

text: After a hundred years of construction and by the beginning of the 15th century, the structure was still missing its dome. The basic features of the dome had been designed by Arnolfo di Cambio in 1296. His brick model, high, long, was standing in a side aisle of the unfinished building, and had long been sacrosanct. It called for an octagonal dome higher and wider than any that had ever been built, with no external buttresses to keep it from spreading and falling under its own weight.


title: Florence Cathedral

text: The commitment to reject traditional Gothic buttresses had been made when Neri di Fioravanti's model was chosen over a competing one by Giovanni di Lapo Ghini. That architectural choice, in 1367, was one of the first events of the Italian Renaissance, marking a break with the Medieval Gothic style and a return to the classic Mediterranean dome. Italian architects regarded Gothic flying buttresses as ugly makeshifts. Furthermore, the use of buttresses was forbidden in Florence, as the style was favored by central Italy's traditional enemies to the north. Neri's model depicted a massive inner dome, open at the top to admit light, like Rome's Pantheon, partly supported by the inner dome, but enclosed in a thinner outer shell, to keep out the weather. It was to stand on an unbuttressed octagonal drum. Neri's dome would need an internal defense against spreading (hoop stress), but none had yet been designed.


title: Florence Cathedral

text: The building of such a masonry dome posed many technical problems. Brunelleschi looked to the great dome of the Pantheon in Rome for solutions. The dome of the Pantheon is a single shell of concrete, the formula for which had long since been forgotten. The Pantheon had employed structural centring to support the concrete dome while it cured. This could not be the solution in the case of a dome this size and would put the church out of use. For the height and breadth of the dome designed by Neri, starting above the floor and spanning , there was not enough timber in Tuscany to build the scaffolding and forms. Brunelleschi chose to follow such design and employed a double shell, made of sandstone and marble. Brunelleschi would have to build the dome out of brick, due to its light weight compared to stone and being easier to form, and with nothing under it during construction. To illustrate his proposed structural plan, he constructed a wooden and brick model with the help of Donatello and Nanni di Banco, a model which is still displayed in the Museo dell'Opera del Duomo. The model served as a guide for the craftsmen, but was intentionally incomplete, so as to ensure Brunelleschi's control over the construction.


title: Florence Cathedral

text: Brunelleschi's solutions were ingenious. The spreading problem was solved by a set of four internal horizontal stone and iron chains, serving as barrel hoops, embedded within the inner dome: one at the top, one at the bottom, with the remaining two evenly spaced between them. A fifth chain, made of wood, was placed between the first and second of the stone chains. Since the dome was octagonal rather than round, a simple chain, squeezing the dome like a barrel hoop, would have put all its pressure on the eight corners of the dome. The chains needed to be rigid octagons, stiff enough to hold their shape, so as not to deform the dome as they held it together.


title: Florence Cathedral

text: Each of Brunelleschi's stone chains was built like an octagonal railroad track with parallel rails and cross ties, all made of sandstone beams in diameter and no more than long. The rails were connected end-to-end with lead-glazed iron splices. The cross ties and rails were notched together and then covered with the bricks and mortar of the inner dome. The cross ties of the bottom chain can be seen protruding from the drum at the base of the dome. The others are hidden. Each stone chain was supposed to be reinforced with a standard iron chain made of interlocking links, but a magnetic survey conducted in the 1970s failed to detect any evidence of iron chains, which if they exist are deeply embedded in the thick masonry walls. Brunelleschi also included vertical "ribs" set on the corners of the octagon, curving towards the center point. The ribs, deep, are supported by 16 concealed ribs radiating from center. The ribs had slits to take beams that supported platforms, thus allowing the work to progress upward without the need for scaffolding.


title: Florence Cathedral

text: A circular masonry dome can be built without supports, called centering, because each course of bricks is a horizontal arch that resists compression. In Florence, the octagonal inner dome was thick enough for an imaginary circle to be embedded in it at each level, a feature that would hold the dome up eventually, but could not hold the bricks in place while the mortar was still wet. Brunelleschi used a herringbone brick pattern to transfer the weight of the freshly laid bricks to the nearest vertical ribs of the non-circular dome.


title: Florence Cathedral

text: The outer dome was not thick enough to contain embedded horizontal circles, being only thick at the base and thick at the top. To create such circles, Brunelleschi thickened the outer dome at the inside of its corners at nine different elevations, creating nine masonry rings, which can be observed today from the space between the two domes. To counteract hoop stress, the outer dome relies entirely on its attachment to the inner dome and has no embedded chains.


title: Florence Cathedral

text: A modern understanding of physical laws and the mathematical tools for calculating stresses were centuries in the future. Brunelleschi, like all cathedral builders, had to rely on intuition and whatever he could learn from the large scale models he built. To lift 37,000 tons of material, including over 4 million bricks, he invented hoisting machines and lewissons for hoisting large stones. These specially designed machines and his structural innovations were Brunelleschi's chief contribution to architecture. Although he was executing an aesthetic plan made half a century earlier, it is his name, rather than Neri's, that is commonly associated with the dome.


title: Florence Cathedral

text: Brunelleschi's ability to crown the dome with a lantern was questioned and he had to undergo another competition, even though there had been evidence that Brunelleschi had been working on a design for a lantern for the upper part of the dome. The evidence is shown in the curvature, which was made steeper than the original model. He was declared the winner over his competitors Lorenzo Ghiberti and Antonio Ciaccheri. His design (now on display in the Museum Opera del Duomo) was for an octagonal lantern with eight radiating buttresses and eight high arched windows. Construction of the lantern was begun a few months before his death in 1446. Then, for 15 years, little progress was possible, due to alterations by several architects. The lantern was finally completed by Brunelleschi's friend Michelozzo in 1461. The conical roof was crowned with a gilt copper ball and cross, containing holy relics, by Verrocchio in 1469. This brings the total height of the dome and lantern to . This copper ball was struck by lightning on 17 July 1600 and fell down. It was replaced by an even larger one two years later.


title: Florence Cathedral

text: The commission for this gilt copper ball [atop the lantern] went to the sculptor Andrea del Verrocchio, in whose workshop there was at this time a young apprentice named Leonardo da Vinci. Fascinated by Filippo's [Brunelleschi's] machines, which Verrocchio used to hoist the ball, Leonardo made a series of sketches of them and, as a result, is often given credit for their invention.


title: Florence Cathedral

text: Leonardo might have also participated in the design of the bronze ball, as stated in the G manuscript of Paris "Remember the way we soldered the ball of Santa Maria del Fiore".


title: Florence Cathedral

text: The decorations of the drum gallery by Baccio d'Agnolo were never finished after being disapproved by no one less than Michelangelo.


title: Florence Cathedral

text: A huge statue of Brunelleschi now sits outside the Palazzo dei Canonici in the Piazza del Duomo, looking thoughtfully up towards his greatest achievement, the dome that would forever dominate the panorama of Florence. It is still the largest masonry dome in the world.


title: Florence Cathedral

text: The building of the cathedral had started in 1296 with the design of Arnolfo di Cambio and was completed in 1469 with the placing of Verrochio's copper ball atop the lantern. But the façade was still unfinished and would remain so until the 19th century.


title: Florence Cathedral

text: The original façade, designed by Arnolfo di Cambio and usually attributed to Giotto, was actually begun twenty years after Giotto's death. A mid-15th-century pen-and-ink drawing of this so-called Giotto's façade is visible in the Codex Rustici, and in the drawing of Bernardino Poccetti in 1587, both on display in the Museum of the Opera del Duomo. This façade was the collective work of several artists, among them Andrea Orcagna and Taddeo Gaddi. This original façade was completed in only its lower portion and then left unfinished. It was dismantled in 1587–1588 by the Medici court architect Bernardo Buontalenti, ordered by Grand Duke Francesco I de' Medici, as it appeared totally outmoded in Renaissance times. Some of the original sculptures are on display in the Museum Opera del Duomo, behind the cathedral. Others are now in the Berlin Museum and in the Louvre.


title: Florence Cathedral

text: The competition for a new façade turned into a huge corruption scandal. The wooden model for the façade of Buontalenti is on display in the Museum Opera del Duomo. A few new designs had been proposed in later years, but the models (of Giovanni Antonio Dosio, Giovanni de' Medici with Alessandro Pieroni and Giambologna) were not accepted. The façade was then left bare until the 19th century.


title: Florence Cathedral

text: In 1864, a competition held to design a new façade was won by Emilio De Fabris (1808–1883) in 1871. Work began in 1876 and was completed in 1887. This neo-gothic façade in white, green and red marble forms a harmonious entity with the cathedral, Giotto's bell tower and the Baptistery, but some think it is excessively decorated.


title: Florence Cathedral

text: The three huge bronze doors date from 1899 to 1903. They are adorned with scenes from the life of the Madonna. The mosaics in the lunettes above the doors were designed by Niccolò Barabino. They represent (from left to right): "Charity among the founders of Florentine philanthropic institutions"; "Christ enthroned with Mary and John the Baptist"; and "Florentine artisans, merchants and humanists". The pediment above the central portal contains a half-relief by Tito Sarrocchi of "Mary enthroned holding a flowered scepter". Giuseppe Cassioli sculpted the right-hand door.


title: Florence Cathedral

text: On top of the façade is a series of niches with the twelve Apostles with, in the middle, the Madonna with Child. Between the rose window and the tympanum, there is a gallery with busts of great Florentine artists.


title: Florence Cathedral

text: The Gothic interior is vast and gives an empty impression. The relative bareness of the church corresponds with the austerity of religious life, as preached by Girolamo Savonarola.


title: Florence Cathedral

text: Many decorations in the church have been lost in the course of time, or have been transferred to the Museum Opera del Duomo, such as the magnificent cantorial pulpits (the singing galleries for the choristers) of Luca della Robbia and Donatello.


title: Florence Cathedral

text: As this cathedral was built with funds from the public, some important works of art in this church honour illustrious men and military leaders of Florence:


title: Florence Cathedral

text: Lorenzo Ghiberti had a large artistic impact on the cathedral. Ghiberti worked with Filippo Brunelleschi on the cathedral for eighteen years and had a large number of projects on almost the whole east end. Some of his works were the stained glass designs, the bronze shrine of Saint Zenobius and marble revetments on the outside of the cathedral.


title: Florence Cathedral

text: Above the main door is the colossal clock face with fresco portraits of four Prophets or Evangelists by Paolo Uccello (1443). This one-handed liturgical clock shows the 24 hours of the "hora italica" (Italian time), a period of time ending with sunset at 24 hours. This timetable was used until the 18th century. This is one of the few clocks from that time that still exist and are in working order.


title: Florence Cathedral

text: The church is particularly notable for its 44 stained glass windows, the largest undertaking of this kind in Italy in the 14th and 15th century. The windows in the aisles and in the transept depict saints from the Old and the New Testament, while the circular windows in the drum of the dome or above the entrance depict Christ and Mary. They are the work of the greatest Florentine artists of their times, such as Donatello, Lorenzo Ghiberti, Paolo Uccello and Andrea del Castagno.


title: Florence Cathedral

text: "Christ crowning Mary as Queen", the stained-glass circular window above the clock, with a rich range of coloring, was designed by Gaddo Gaddi in the early 14th century.


title: Florence Cathedral

text: Donatello designed the stained-glass window ("Coronation of the Virgin") in the drum of the dome (the only one that can be seen from the nave).


title: Florence Cathedral

text: The beautiful funeral monument of Antonio d'Orso (1323), bishop of Florence, was made by Tino da Camaino, the most important funeral sculptor of his time.


title: Florence Cathedral

text: The monumental crucifix, behind the Bishop's Chair at the high altar, is by Benedetto da Maiano (1495–1497). The choir enclosure is the work of the famous Bartolommeo Bandinelli. The ten-paneled bronze doors of the sacristy were made by Luca della Robbia, who has also two glazed terracotta works inside the sacristy: "Angel with Candlestick" and "Resurrection of Christ".


title: Florence Cathedral

text: In the back of the middle of the three apses is the altar of Saint Zanobius, first bishop of Florence. Its silver shrine, a masterpiece of Ghiberti, contains the urn with his relics. The central compartment shows us one of his miracles, the reviving of a dead child. Above this shrine is the painting "Last Supper" by the lesser-known Giovanni Balducci. There was also a glass-paste mosaic panel "The Bust of Saint Zanobius" by the 16th-century miniaturist Monte di Giovanni, but it is now on display in the Museum Opera del Duomo.


title: Florence Cathedral

text: Many decorations date from the 16th-century patronage of the Grand Dukes, such as the pavement in colored marble, attributed to Baccio d'Agnolo and Francesco da Sangallo (1520–26). Some pieces of marble from the façade were used, topside down, in the flooring (as was shown by the restoration of the floor after the 1966 flooding).


title: Florence Cathedral

text: The ceiling of the dome is decorated with a representation of "The Last Judgment". Originally left whitewashed following its completion it was the Grand Duke Cosimo I de' Medici who decided to have the ceiling of the dome painted. This enormous work, 3,600 metres² (38 750 ft²) of painted surface, was started in 1572 by Giorgio Vasari and would not be completed until 1579. The upper portion, near the lantern, representing "The 24 Elders of Apocalypse" was finished by Vasari before his death in 1574. Federico Zuccari with the assistance of Bartolomeo Carducci, Domenico Passignano and Stefano Pieri finished the other portions: (from top to bottom) "Choirs of Angels"; "Christ, Mary and Saints"; "Virtues, Gifts of the Holy Spirit and Beatitudes"; and at the bottom of the cupola: "Capital Sins and Hell". These frescoes are considered Zuccari's greatest work. But the quality of the work is uneven because of the input of different artists and the different techniques. Vasari had used "true fresco", while Zuccari had painted "in secco". During the restoration work, which ended in 1995, the entire pictorial cycle of "The Last Judgment" was photographed with specially designed equipment and all the information collected in a catalogue. All the restoration information along with reconstructed images of the frescos were stored and managed in the Thesaurus Florentinus computer system.


title: Florence Cathedral

text: In 1475 the Italian astronomer Paolo dal Pozzo Toscanelli (who was also a mathematical tutor of Brunelleschi) pierced a hole in the dome at above the pavement to create a meridian line. The height precluded the installation of a complete meridian line on the floor of the cathedral, but allowed a short section of approximately to run between the main altar and the north wall of the transept. This allows for observation for around 35 days either side of the summer solstice .


title: Florence Cathedral

text: Due to settlement in the building and also movements due to the outside temperature changes, the meridian line had limited astronomical value and fell into disuse until it was restored in 1755 by Leonardo Ximenes.


title: Florence Cathedral

text: The meridian line was covered over by the "fabbricieri" in 1894 and unveiled again in 1997. A yearly re-enacement of the observation takes place on 21 June each year at 12.00 UT.


title: Florence Cathedral

text: The cathedral underwent difficult excavations between 1965 and 1974. The archaeological history of this huge area was reconstructed through the work of Dr. Franklin Toker: remains of Roman houses, an early Christian pavement, ruins of the former cathedral of Santa Reparata and successive enlargements of this church. Close to the entrance, in the part of the crypt open to the public, is the tomb of Brunelleschi. While its location is prominent, the actual tomb is simple and humble. That the architect was permitted such a prestigious burial place is proof of the high esteem he was held in by the Florentines.


title: Florence Cathedral

text: The unreinforced masonry that Brunelleschi used to construct the dome is weak in tension which leads to cracking when tensile stresses exceed the limited masonry tensile strength. The material is especially susceptible to damage from seismic loading due to its heterogeneity and many surfaces between different materials (stones to mortar connection).


title: Florence Cathedral

text: Cracking of the dome was observed even before its construction was completed. It is possible that the first cracks were caused by a strong earthquake in 1453.


title: Florence Cathedral

text: The first written evidence about the presence of cracks appears in a report by Gherardo Silvani report dated 18 September 1639 which refers to “peli” (“hairs”). In 1694 Gianbattista Nelli and Vincenzo Viviani surveyed the cracks with Nelli recording that there were two major cracks with a maximum width of . They believed that the cracks were caused by the weight of the dome, and the resulting the horizontal thrusts on the pillars.


title: Florence Cathedral

text: A commission, headed by Vincenzo Viviani carried out investigations in 1695 and came to the conclusion that the cracking was due to the dead weight of the buildings, it was proposed that the dome be strengthened by installing four large iron belts; three on the outside of the dome between the bugling area of the dome and the circular windows, while the fourth would be installed internally in the second walkway between the two shells. This was similar to what had been done on the dome of St. Peter's in Rome. After a long debate, a decision was made to leave the dome as it was.


title: Florence Cathedral

text: The first most complete survey of the cracks was published in 1757 by the Jesuit Leonardo Ximenes (1716–1786). In his document he described 13 different crack typologies.


title: Florence Cathedral

text: In 1934, Pier Luigi Nervi, who was head of a special commission established by the Opera del Duomo to study the cracking observed that the cracks opened and closed with the seasons. In the winter, the dome's stone and bricks would contract causing the cracks to widen while over the summer the materials would expand and the cracks would close up.


title: Florence Cathedral

text: While modern buildings by design incorporate expansion joints, the cathedral's dome does not include any and so subsequently developed its own expansion joints in the form of these cracks which allowed the structure to “breathe”. To date they have not caused any catastrophic damage to the dome.


title: Florence Cathedral

text: In 1955 the Opera del Duomo installed 22 mechanical deformometers, which were read four times a year to record the variations in the width of the major cracks in the inner dome. At the same time the dome's internal and external temperatures were also recorded. This remained in service until 2009.


title: Florence Cathedral

text: In 1978 a government culture agency decided to restore the frescoes. Brunelleschi left forty eight holes in the base of the dome. They are open on the inside and covered by the outer skin of the dome. It has long been assumed that the holes simply served as mounts for the scaffold used when frescoes were painted on the inside of the dome. While the holes had been able to support the scaffolding used for the creation of the frescos on the interior of the dome they were not strong enough for the network of modern metal scaffolding necessary to provide access for the restoration work undertaken on the frescos between 1979 and 1995. To strengthen the scaffolding, the private company contracted to build scaffolding for the work was allowed in 1982 to fill the holes with concrete so that steel beams could be anchored in them.