JSONitzan Bartana -violinKerry Startton - conductorJerusalem TheaterApril 15 What came as a surprise at the Jerusalem Symphony Orchestra’s concert last week was not so much its rather standard program, but 21-year-old Nitzan Bartana’s rendition of Paganini’s Violin Concerto No. 2.She tossed off this enormously demanding work with brilliant virtuosity, ease and nonchalance, overcoming the formidable technical hurdles effortlessly, as a matter of course. Her intonation was impeccably pure, her articulation incisive and significant. Melodious themes were well-shaped, with an appealing songful sound. Even for many mature celebrity violinists this technically difficult work is a formidable challenge. Paganini might have been pleased.Something of a surprise was also Canadian conductor Kerry Startton, till now unknown on these shores. In Rossini’s Silk Ladder Overture, and then in Beethoven’s Symphony No. 2, he struck a brisk, invigorating tempo, fast but not over-hurried, with no swallowed notes despite the speed. Into Beethoven’s often-heard symphony he injected refreshing energies, overcoming the contempt that could have been bred by the work’s familiarity.