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Topic Review
Vickrey Auction
A Vickrey auction is a type of sealed-bid auction. Bidders submit written bids without knowing the bid of the other people in the auction. The highest bidder wins but the price paid is the second-highest bid. This type of auction is strategically similar to an English auction and gives bidders an incentive to bid their true value. The auction was first described academically by Columbia University professor William Vickrey in 1961 though it had been used by stamp collectors since 1893. In 1797 Johann Wolfgang von Goethe sold a manuscript using a sealed-bid, second-price auction. Vickrey's original paper mainly considered auctions where only a single, indivisible good is being sold. The terms Vickrey auction and second-price sealed-bid auction are, in this case only, equivalent and used interchangeably. When either a divisible good or multiple identical goods are sold in a single auction, however, these terms are used differently. In the case of multiple identical goods, the bidders submit inverse demand curves and pay the opportunity cost. Vickrey auctions are much studied in economic literature but uncommon in practice. Generalized variants of the Vickrey auction for multiunit auctions exist, such as the generalized second-price auction used in Google's and Yahoo!'s online advertisement programmes (not incentive compatible) and the Vickrey-Clarke-Grove Auction (incentive compatible).
  • 1.1K
  • 04 Nov 2022
Topic Review
Vicious Cycle of Obesity, Inflammation, and Breast Cancer
Epidemiological studies refer to obesity-associated metabolic changes as a critical risk factor behind the progression of breast cancer. The plethora of signals arising due to obesity-induced changes in adipocytes present in breast tumor microenvironment, significantly affect the behavior of adjacent breast cells. Adipocytes from white adipose tissue are currently recognized as an active endocrine organ secreting different bioactive compounds. However, due to excess energy intake and increased fat accumulation, there are morphological followed by secretory changes in adipocytes, which make the breast microenvironment proinflammatory. This proinflammatory milieu not only increases the risk of breast cancer development through hormone conversion, but it also plays a role in breast cancer progression through the activation of effector proteins responsible for the biological phenomenon of metastasis.
  • 427
  • 08 Apr 2022
Topic Review
Vici Syndrome
Vici syndrome is a severe disorder that begins early in life and affects many body systems. It is characterized by abnormalities of the brain, immune system, heart, skin, and eyes. Other organs and tissues are less commonly affected.  
  • 365
  • 23 Dec 2020
Topic Review
Vichy France
Vichy France (French: Régime de Vichy) is the common name of the French State (État français) headed by Marshal Philippe Pétain during World War II. Evacuated from Paris to Vichy in the unoccupied "Free Zone" (zone libre) in the southern part of metropolitan France which included French Algeria, it remained responsible for the civil administration of all France as well as the French colonial empire. From 1940 to 1942, while the Vichy regime was the nominal government of all of France except for Alsace-Lorraine, the Germans militarily occupied northern France. While Paris remained the de jure capital of France, the government chose to relocate to the town of Vichy, 360 km (220 mi) to the south in the zone libre, which thus became the de facto capital of the French State. Following the Allied landings in French North Africa in November 1942, southern France was also militarily occupied by Germany and Italy to protect the Mediterranean coastline. Petain's government remained in Vichy as the nominal government of France, albeit one that was obliged by circumstances to collaborate with Germany from November 1942 onwards. The government at Vichy remained there until late 1944, when it lost its authority due to the Allied invasion of France. After being appointed Premier by President Albert Lebrun, Marshal Pétain's cabinet agreed to end the war and signed an Armistice with Germany on 22 June 1940. On 10 July, the French Third Republic was dissolved, and Pétain established an authoritarian regime when the National Assembly granted him full powers. The Vichy government reversed many liberal policies and began tight supervision of the economy, calling for "National Regeneration", with central planning a key feature. Labour unions came under tight government control. Conservative Catholics became prominent and clerical input in schools resumed. Paris lost its avant-garde status in European art and culture. The media were tightly controlled and stressed virulent anti-Semitism, and, after June 1941, anti-Bolshevism. The French State maintained nominal sovereignty over the whole of French territory, but had effective full sovereignty only in the unoccupied southern zone libre ("free zone"). It had limited and only civil authority in the northern zones under military occupation. The occupation was to be a provisional state of affairs, pending the conclusion of the war, which at the time (1940) appeared imminent. The occupation also presented certain advantages, such as keeping the French Navy and French colonial empire under French control, and avoiding full occupation of the country by Germany, thus maintaining a degree of French independence and neutrality. The French government at Vichy never joined the Axis alliance. Germany kept two million French soldiers prisoner, carrying out forced labour. They were hostages to ensure that Vichy would reduce its military forces and pay a heavy tribute in gold, food, and supplies to Germany. French police were ordered to round up Jews and other "undesirables" such as communists and political refugees. Much of the French public initially supported the government, despite its undemocratic nature and its difficult position vis-à-vis the Germans, often seeing it as necessary to maintain a degree of French autonomy and territorial integrity. In November 1942, however, the zone libre was also occupied by Axis forces, leading to the disbandment of the remaining army and the sinking of France's remaining fleet and ending any semblance of independence, with Germany now closely supervising all French officials. Most of the overseas French colonies were originally under Vichy control, but with the Allied invasion of North Africa it lost one colony after another to Charles de Gaulle's Allied-oriented Free France. Public opinion in some quarters turned against the French government and the occupying German forces over time, when it became clear that Germany was losing the war, and resistance to them increased. Following the Allied invasion of France in June 1944 and the liberation of France later that year, the Free French Provisional government of the French Republic (GPRF) was installed by the Allies as France's government, led by de Gaulle. Under a "national unanimity" cabinet uniting the many factions of the French Resistance, the GPRF re-established a provisional French Republic, thus apparently restoring continuity with the Third Republic. Most of the legal French government's leaders at Vichy fled or were subject to show trials by the GPRF, and a number were quickly executed for "treason" in a series of purges (épuration légale). Thousands of collaborators were summarily executed by local communists and the Resistance in so-called "savage purges" (épuration sauvage). The last of the French state exiles were captured in the Sigmaringen enclave by de Gaulle's French 1st Armoured Division in April 1945. Pétain, who had voluntarily made his way back to France via Switzerland, was also put on trial for treason by the new Provisional government, and received a death sentence, but this was commuted to life imprisonment by de Gaulle. Only four senior Vichy officials were tried for crimes against humanity, although many more had participated in the deportation of Jews for extermination in Nazi concentration camps, abuses of prisoners, and severe acts against members of the Resistance.
  • 6.3K
  • 09 Nov 2022
Topic Review
Vice News
Vice News (stylized as VICE News) is Vice Media's current affairs channel, producing daily documentary essays and video through its website and YouTube channel. It promotes itself on its coverage of "under-reported stories". Vice News was created in December 2013 and is based in New York City , though it has bureaus worldwide.
  • 888
  • 14 Oct 2022
Topic Review
Vicara
Vicara (Sanskrit( विचार) and Pali, also vicāra; Tibetan phonetic: chöpa) is a Sanskrit term that is translated as "discernment", "sustained thinking", etc. It is an essential element of dhyana, meditation, both in the Buddhist and the Hindu traditions. In the Theravada tradition, it is defined as the sustained application of the mind on an object. In the Mahayana tradition, vicara is defined as a mental factor that scrutinizes finely to discern the specific details. In Hinduism, it is part of Patanjali's Samprajatna samadhi, and also well known as atma-vichara or self-inquiry.
  • 1.0K
  • 14 Nov 2022
Topic Review
Vicar Apostolic
An apostolic vicariate is a form of territorial jurisdiction of the Catholic Church centered in missionary regions and countries where a diocese has not yet been established. It is essentially provisional, though it may last for a century or more. The hope is that the region will generate sufficient numbers of Catholics for the Church to create a diocese. In turn, the status of Apostolic vicariate is often a promotion for a former apostolic prefecture, while either may have started out as a mission sui iuris.
  • 763
  • 26 Oct 2022
Topic Review
Vibrotactile Feedback in Virtual Reality
While substantial progress in computer graphics and sound rendering has resulted in highly realistic visual and auditory experiences in virtual reality (VR), achieving genuine immersion, interactivity, and the stimulation of imagination necessitates the integration of realistic tactile experiences, often facilitated through haptic feedback. The incorporation of vibrotactile feedback in VR allows users to fully engage their sense of touch, enabling them to explore, grasp, and manipulate virtual objects as if they were interacting with them in the physical world.
  • 612
  • 22 Jan 2024
Topic Review Peer Reviewed
Vibroacoustic Pollution in the Neonatal Ward
Excessive noise pollution is often a problem for neonatal nurseries. Noise pollution involves not only noise but also vibrations. The main difference between them is that noise can be heard, and vibrations are felt. The human ear cannot detect waves outside the range of 20 Hz–20 KHz. Waves from 0 Hz to 80–100 Hz should be considered vibrations. Both can be transmitted to the neonate through the incubator’s operational mechanisms and other noise sources. Neonatal units’ noise is well studied but very little is known about vibration. This entry focuses on the importance of vibrations reaching the inside of incubators in neonatal nurseries.
  • 567
  • 25 Dec 2023
Topic Review
Vibratory Urticaria
Vibratory urticaria is a condition in which exposing the skin to vibration, repetitive stretching, or friction results in allergy symptoms such as hives (urticaria), swelling (angioedema), redness (erythema), and itching (pruritus) in the affected area.
  • 498
  • 23 Dec 2020
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