$(document).ready(function() { 
    $("#seminars").tablesorter({ 
        // pass the headers argument and assing a object 
        headers: { 
            // assign the secound column (we start counting zero) 
            4: { 
                // disable it by setting the property sorter to false 
                sorter: false 
            }
		
        } 
    }); 
});

/*$(document).ready(function() { 
    // call the tablesorter plugin 
    $("#seminars").tablesorter({ 
        // sort on the first column and third column, order asc 
        sortList: [[0,0]] 
    }); 
});*/