In reference to the patent: US 2012/0319859 A1
Would you please tell me why there is a difference in time between the assignment date and publication date? Is it abandoned?
I don't want to conflate the legal status of the application(s) with the time gap between publication and assignment. An assignment can happen during examination of the application or after the patent is granted, so there is not necessarily a link between the assignment of this application and the date of publication.
As is the case for many patents, it is difficult to completely answer the question about the US application without digging in to the related international applications. This US application is based on a PCT application from Israel (PCT/IL2011/000071), which you can find by clicking on the WIPO application number (WO 2011/089606 A1).
Office Entry Date National Number National Status European Patent Office 17.07.2012 2011706029 Published: 28.11.2012 Withdrawn: 20.02.2013 Israel 18.07.2012 221000
In the USPTO Public Pair system, the status of the US application is listed as:
Status: Abandoned -- Failure to Respond to an Office Action 10-21-2014 Mail Abandonment for Failure to Respond to Office Action 10-16-2014 Aband. for Failure to Respond to O. A. 03-24-2014 CTNF Non-Final Rejection
So, to answer part of your question, yes, the European patent (EP) has been withdrawn, and the US application is currently listed as abandoned (although it could potentially be revived).
Now, looking at the PCT application in PatentScope, we can find the information that answers the question:
Applicants: CREATIVE TEAM INSTRUMENTS LTD. [IL/IL] (For All Designated States Except US). TAUB, Ilan [IL/IL]; (IL) (For US Only) REIFMAN, Mark [IL/IL]; (IL) (For US Only) Priority Data: 61/296,643 20.01.2010 US
The PCT application is actually based on a US Provisional Application filed January 20, 2010 by the inventors. The PCT application named the company in Israel as the applicant in all states except the US, so ultimately an assignment would have been necessary for the US application. Indeed, an assignment occurred on December 20, 2012.