Abstract: Techniques for multi-stream transactional event processing under ACID semantics in a distributed log-based append-only datastore are described. A transaction coordinator writes events that are part of a transaction to a transaction buffer, where the events can be made visible to clients involved in the transaction while other clients are not aware. Upon committing the transaction, an optimistic concurrency control based technique is utilized to attempt to obtain locks on all events involved in the transaction across one or multiple shards by one or multiple designated writer nodes. When all involved writer nodes indicate that they are able to commit their events, the transaction can be committed.

Abstract: A respiratory mask for use in relatively cold environments configured to fit over the nose and mouth of the wearer. The mask is constructed of an insulating material with a flow-through opening therein in spaced alignment with at least the mouth of the wearer. The flow-through opening is filled with a thermally conductive mesh material wherein all of the fluids flowing into the interior of the mask and all of the fluids flowing out of the mask must flow through said thermally conductive material.