Problem: Data compression:

Lossless audio compression produces a representation of digital data that decompress to an exact digital duplicate of the original audio stream, unlike playback from lossy compression techniques such as Vorbis and MP3. Compression ratios are around 5060% of original size, which is similar to those for generic lossless data compression. Lossless compression is unable to attain high compression ratios due to the complexity of waveforms and the rapid changes in sound forms. Codecs like FLAC, Shorten and TTA use linear prediction to estimate the spectrum of the signal. Many of these algorithms use convolution with the filter [-1 1] to slightly whiten or flatten the spectrum, thereby allowing traditional lossless compression to work more efficiently. The process is reversed upon decompression.

What compression cannot attain high work efficiently?
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A: unanswerable

Problem: The problem of the flow of time, as it has been treated in analytic philosophy, owes its beginning to a paper written by J. M. E. McTaggart. In this paper McTaggart proposes two "temporal series". The first series, which means to account for our intuitions about temporal becoming, or the moving Now, is called the A-series. The A-series orders events according to their being in the past, present or future, simpliciter and in comparison to each other. The B-series eliminates all reference to the present, and the associated temporal modalities of past and future, and orders all events by the temporal relations earlier than and later than.
What was McTaggart's first series called?
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Answer: the A-series

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The Paris Region had 5.4 million salaried employees in 2010, of whom 2.2 million were concentrated in 39 poles d'emplois or business districts. The largest of these, in terms of number of employees, is known in French as the QCA, or quartier central des affaires; it is in the western part of the City of Paris, in the 2nd, 8th, 9th, 16th and 18th arrondissements. In 2010 it was the workplace of 500,000 salaried employees, about thirty percent of the salaried employees in Paris and ten percent of those in the Ile-de-France. The largest sectors of activity in the central business district were finance and insurance (16 percent of employees in the district) and business services (15 percent). The district also includes a large concentration of department stores, shopping areas, hotels and restaurants, as well a government offices and ministries.
How many salaried employees lived in the Paris Region in 2010?
A: 5.4 million

Context and question: Studies conducted on both animals and humans show major bidirectional relationships between the circadian system and abusive drugs. It is indicated that these abusive drugs affect the central circadian pacemaker. Individuals suffering from substance abuse display disrupted rhythms. These disrupted rhythms can increase the risk for substance abuse and relapse. It is possible that genetic and/or environmental disturbances to the normal sleep and wake cycle can increase the susceptibility to addiction.
What can disruption to genetics and environment in the sleep cycle cause?
Answer: susceptibility to addiction

Question: Boston has been called the "Athens of America" for its literary culture, earning a reputation as "the intellectual capital of the United States." In the nineteenth century, Ralph Waldo Emerson, Henry David Thoreau, Nathaniel Hawthorne, Margaret Fuller, James Russell Lowell, and Henry Wadsworth Longfellow wrote in Boston. Some consider the Old Corner Bookstore, where these writers met and where The Atlantic Monthly was first published, to be "cradle of American literature. In 1852, the Boston Public Library was founded as the first free library in the United States. Boston's literary culture continues today thanks to the city's many universities and the Boston Book Festival.
Is there an answer to this question: What century did Ralph Waldo Emerson write in?

Answer: the nineteenth century

Question: Originally much of the valley laid beneath the waters of Lake Texcoco, a system of interconnected salt and freshwater lakes. The Aztecs built dikes to separate the fresh water used to raise crops in chinampas and to prevent recurrent floods. These dikes were destroyed during the siege of Tenochtitlan, and during colonial times the Spanish regularly drained the lake to prevent floods. Only a small section of the original lake remains, located outside the Federal District, in the municipality of Atenco, State of Mexico.
Is there an answer to this question: What made up Lake Texcoco?

Answer:
a system of interconnected salt and freshwater lakes