A slew of updates from publishers has sent the media sector higher.Specialist publisher and events organiser United Business Media (UBM) pleased the market by announcing that is to acquire Canon Communications, a trade show organiser specialising in the medical devices sector, for £185m.Dods is benefiting from political anoraks' thirst for knowledge about the new coalition but feeling the pinch from public sector cuts, the publisher of The House Magazine and several political almanacs said as it posted bigger losses. The shares crept slightly higher.Not all stocks in the sector are in demand though.Centaur Media, the publishing and events group behind titles such as Marketing Week, fell back a little after it hailed a recovery in advertising markets as it returned to profit.And Vitesse Media, the publisher behind business titles such as Growth Company Investor, crashed even after saying it moved into profit in the half year to July 31, helped by growth in its online business.Pre-tax profits for the period totalled £33,000, against a loss of £90,000 the previous year. Revenues fell to £1.56m from £1.86, partly because the company's big event the Growth Company Investor Show is being held later this month rather than in June.The defence sector is under attack.Among the fallers is Chemring, the military decoy flares and mine detection firm despite strong results. The company has kept up the good work during the second half, firing a 23% increase in revenue for the four months since May 1.The group, still clearing up after a fire at one of its assembly facilities in Tennessee, said sales for the period jumped to £176m from £143m and had risen 15% to £432m over the ten months.Top performing sectors so far todayOil & Gas Producers 7,251.44 +0.96%Construction & Materials 3,391.04 +0.81%Personal Goods 16,309.62 +0.07%Media 3,856.70 +0.03%Bottom performing sectors so far todayAerospace and Defence 3,178.83 -1.73%Fixed Line Telecommunications 1,975.06 -1.53%Alternative Energy 3,501.87 -1.22%Real Estate Investment & Services 1,450.49 -1.12%Automobiles & Parts 3,701.16 -1.00%