using (KeywordQuery query = new KeywordQuery(site))
                {
                            var fedManager = new FederationManager(application);
                            var owner = new SearchObjectOwner(SearchObjectLevel.SPSite, site.RootWeb);

                            query.SourceId = fedManager.GetSourceByName("NewsRS", owner).Id;
                            query.QueryText = string.Format("WorkflowStatusOWSCHCS:Approved PublishedUntilDate>="{0}" OR NewsNewsPublishedDate<="{0}"", DateTime.Now);
                            query.KeywordInclusion = KeywordInclusion.AllKeywords;
                            query.RowLimit = 5;
                            query.StartRow = 1;
                            query.SelectProperties.Add("NewsFriendlyUrl");
                            query.SelectProperties.Add("NewsNewsTeaser");
                            query.SelectProperties.Add("NewsNewsDate");
                            query.SelectProperties.Add("NewsPublishedUntilDate");
                            query.SelectProperties.Add("NewsNewsContent");
                            query.SelectProperties.Add("NewsNewsPublishedDate");
                            query.SelectProperties.Add("NewsNewsImage");
                            query.SortList.Add("NewsNewsDate", SortDirection.Descending);
                            var searchExecutor = new SearchExecutor();
                            var myResults = searchExecutor.ExecuteQuery(query);
}
}