anchor.diff:        .attr("d", arc);
           
       svg.append("path")
  -      .attr("id", "short")
  +      .attr("id", "long")
         .datum({startAngle: scale(0), endAngle: scale(0), innerRadius: radius-80})
  -      .style("fill", "bbb")
  +      .style("fill", "ddd")
         .attr("d", arc)
         .each(function(d) { console.log(d); this._current = d; });
         
  
positive.code: 
      function updateData() {
      
        d3.json("/event?expression=kernel(all.load)&limit=2", function(json) {
  
          console.log(json);
          var data = {};
  
          json.forEach(function(d) {
              
            data.host = d.data.all.load.host;
            data.time = d.time;
          
            d.data.all.load.values.forEach(function(v) {
              switch(v.instance) {
                case 1:
                  data['short'] = v.value;
                  break;
                case 5:
                  data['med'] = v.value;
                  break;
                case 15:
                  data['long'] = v.value;
                  break;
                default:
                  console.log("Invalid instance", v);
                  break;
              }
            });
          });
  
          console.log(data);
          
          host.text(data.host);
  
negative.code:       .each(function(d) { console.log(d); this._current = d; });
        
      svg.append("path")
        .attr("id", "short")
        .datum({startAngle: scale(0), endAngle: scale(0), innerRadius: radius-40})
        .style("fill", "bbb")
        .attr("d", arc)
        .each(function(d) { console.log(d); this._current = d; });
        
  