2000s in the music industry Inc.), who surpassed Wal-Mart to become the US’s largest music retailer in April 2008. Sector leaders include: Many hundreds more stores operate worldwide, often prominent only in particular countries or specialist genres. A third kind of operator never retails directly to the public, instead offering branded whitelabel stores and portals for organisations including bricks-and-mortar music stores, mobile telephony operators and ISPs. Some services which initially only offered streaming of tracks now also offer a-la-carte downloads, either through third parties (e.g. Spotify) or fully integrated (Deezer, Juno Digital, Rhapsody etc.). In 2009 "Rolling Stone" reported a price war between iTunes and
Tidal volume Tidal volume Tidal volume (symbol V or TV) is the lung volume representing the normal volume of air displaced between normal inhalation and exhalation when extra effort is not applied. In a healthy, young human adult, tidal volume is approximately 500 mL per inspiration or 7 mL/kg of body mass. Tidal volume plays a significant role during mechanical ventilation to ensure adequate ventilation without causing trauma to the lungs. Tidal volume is measured in milliliters and ventilation volumes are estimated based on a patient's ideal body mass. Measurement of tidal volume can be affected (usually overestimated) by leaks in the