Abstract: Methods, systems, apparatuses, devices, and computer program products are described. A group-based communication system may determine timing for sending notifications to users of the group-based communication system to improve the likelihood of the users interacting with the notifications, interacting with other users in the system, or both. For example, the group-based communication system may identify a notification to send to a user, where the user is associated with a user identifier and a workspace identifier in the group-based communication system. The system may dynamically determine a time for sending the notification based on activity data for the user corresponding to the user identifier and activity data for multiple other users corresponding to the workspace identifier (e.g., members of a team with the user). The system may send the notification for display in a user interface of a user device operated by the user at the determined time.

Abstract: Porous silicon and methods for preparation and use of the same are disclosed. The porous silicon materials have utility either alone or in combination with other materials, for example, combined with carbon particles for energy storage applications.

Abstract: Method and apparatus for evaluating user movement in a fulfillment center. A plurality of sub-tasks for performing a fulfillment operation are determined. Embodiments retrieve a training set of motion data that includes a plurality of training motion data samples, each specifying motion data over a respective window of time, and train a first data model to classify instances of motion data into portions, based on the plurality of sub-tasks. At least one data model is trained to assess performance of the fulfillment operation, using the training set of motion data. An instance of motion data describing motion performed during the fulfillment operation is received, the instance of motion data is divided into a plurality of portions, using the first data model, and a measure of quality is generated, by analyzing the plurality of portions of the instance of motion data using the trained at least one data model.