eScience Group, Microsoft Research, Los Angeles, CA 90024, USA. jennl@microsoft.com|eScience Group, Microsoft Research, Los Angeles, CA 90024, USA. jennl@microsoft.com|eScience Group, Microsoft Research, Los Angeles, CA 90024, USA. jennl@microsoft.com|eScience Group, Microsoft Research, Los Angeles, CA 90024, USA. jennl@microsoft.com|eScience Group, Microsoft Research, Los Angeles, CA 90024, USA. jennl@microsoft.com|eScience Group, Microsoft Research, Los Angeles, CA 90024, USA. jennl@microsoft.com