Possessive (nominal) and indirect object (clausal) clitics are homophonous within the Balkan Slavic languages and Romanian. Pancheva (2004) shows that this syncretism is not just morphophonological but that the two types of clitics constitute identical feature bundles bearing dative case. Yet, these dative clitics seem to exhibit distinct behavior in the nominal and clausal domains: in Bulgarian the nominal clitics appear in second position within the nominal phrase while the clausal clitics are verb-adjacent and non-initial within the clause. It is puzzling that the same syntactic objects exhibit such different distributional patterns. I argue that in Bulgarian this seemingly distinct behavior follows from the interaction of a distributional constraint on dative clitics, NonInitiality within Spell-Out domains, and the different structural properties of the syntactic domains they are associated with. In particular, a number of constituents can be pre-clitic in clauses because various structural positions are available above the clitic, while in nominal phrases no comparable positions are available. Besides the direct consequences of this approach for the treatment of cliticization, it also provides an insight into the nature of Spell-Out domains, nominal and clausal structure, and the nature of syntax/PF interactions.

At Hanford, Savannah River, Oak Ridge, Idaho National Engineering and Environmental Laboratory (INEEL), and other DOE sites, field vadose zone observations have shown complex water seepage and mass transport behavior in a highly heterogeneous, thick vadose zone on a variety of scales. Recent investigation showed that severe contamination of soils and groundwater by organic contaminant and nuclear waste occurred because of water seepage and contaminant transport along localized, preferential, fast flow within the heterogeneous vadose zone. However, most of the existing characterization and monitoring methods are not able to locate these localized and persistent preferential pathways associated with specific heterogeneous geologic features, such as clastic dikes, caliche layers, or fractures. In addition, changes in the chemical composition of moving and indigenous solutes, particularly sodium concentration, redox conditions, biological transformation of organic materials, and high temperature, may significantly alter water, chemicals, and bio-transformation exchange between the zones of fast flow and the rest of the media. In this paper, using the data from Hanford and INEEL sites, we will (1) present evidence that central problems of the vadose zone investigations are associated with preferential, fast flow phenomena and accelerated migration of organic and radioactive elements, (2) identify gaps in current characterization and monitoring technologies, and (3) recommend actions for the development of advanced vadose zone characterization and monitoring methods using a combination of hydrologic, geochemical, and geophysical techniques.