window.addEvent('domready', function() {

    nav1_on = new Image();nav1_on.src   = "tl_files/disturbanity/layout/topnav_about1.png";
    nav2_on = new Image();nav2_on.src   = "tl_files/disturbanity/layout/topnav_publications1.png";
    nav3_on = new Image();nav3_on.src   = "tl_files/disturbanity/layout/topnav_contact1.png";
    nav4_on = new Image();nav4_on.src   = "tl_files/disturbanity/layout/topnav_new1.jpg";
    
    nav1_off = new Image();nav1_off.src = "tl_files/disturbanity/layout/topnav_about0.png";
    nav2_off = new Image();nav2_off.src = "tl_files/disturbanity/layout/topnav_publications0.png";
    nav3_off = new Image();nav3_off.src = "tl_files/disturbanity/layout/topnav_contact0.png";
    nav4_off = new Image();nav4_off.src = "tl_files/disturbanity/layout/topnav_new0.jpg";

    /* about */
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    var out = function(){$('about').set('src',nav1_off.src);};
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    $('navAbout').addEvent('mouseout', out);
    if ("about" == $$('body').get('class')) {
        $('about').set('src',nav1_on.src);
        $('navAbout').removeEvent('mouseout',out);
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    /* publications */
    var over = function(){$('publications').set('src',nav2_on.src);};
    var out = function(){$('publications').set('src',nav2_off.src);};
    $('navPublications').addEvent('mouseover', over);
    $('navPublications').addEvent('mouseout', out);
    if ("publications" == $$('body').get('class')) {
        $('publications').set('src',nav2_on.src);
        $('navPublications').removeEvent('mouseout',out);
    }

    /* contact */
    var over = function(){$('contact').set('src',nav3_on.src);};
    var out = function(){$('contact').set('src',nav3_off.src);};
    $('navContact').addEvent('mouseover', over);
    $('navContact').addEvent('mouseout', out);
    if ("contact" == $$('body').get('class')) {
        $('contact').set('src',nav3_on.src);
        $('navContact').removeEvent('mouseout',out);
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    /* news */
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    var out = function(){$('new').set('src',nav4_off.src);};
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    $('navNew').addEvent('mouseout', out);
    if ("new" == $$('body').get('class')) {
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        $('navNew').removeEvent('mouseout',out);
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});